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Suding KN, Collins CG, Hallett LM, Larios L, Brigham LM, Dudney J, Farrer EC, Larson JE, Shackelford N, Spasojevic MJ. Biodiversity in changing environments: An external-driver internal-topology framework to guide intervention. Ecology 2024; 105:e4322. [PMID: 39014865 DOI: 10.1002/ecy.4322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 01/15/2024] [Accepted: 03/08/2024] [Indexed: 07/18/2024]
Abstract
Accompanying the climate crisis is the more enigmatic biodiversity crisis. Rapid reorganization of biodiversity due to global environmental change has defied prediction and tested the basic tenets of conservation and restoration. Conceptual and practical innovation is needed to support decision making in the face of these unprecedented shifts. Critical questions include: How can we generalize biodiversity change at the community level? When are systems able to reorganize and maintain integrity, and when does abiotic change result in collapse or restructuring? How does this understanding provide a template to guide when and how to intervene in conservation and restoration? To this end, we frame changes in community organization as the modulation of external abiotic drivers on the internal topology of species interactions, using plant-plant interactions in terrestrial communities as a starting point. We then explore how this framing can help translate available data on species abundance and trait distributions to corresponding decisions in management. Given the expectation that community response and reorganization are highly complex, the external-driver internal-topology (EDIT) framework offers a way to capture general patterns of biodiversity that can help guide resilience and adaptation in changing environments.
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Affiliation(s)
- Katharine N Suding
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado, USA
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA
| | - Courtney G Collins
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA
- Biodiversity Research Centre, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Lauren M Hallett
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA
- Department of Biology and Environmental Studies Program, University of Oregon, Eugene, Oregon, USA
| | - Loralee Larios
- Department of Botany & Plant Sciences, University of California Riverside, Riverside, California, USA
| | - Laurel M Brigham
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado, USA
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
| | - Joan Dudney
- Environmental Studies Program, Santa Barbara, California, USA
- Bren School of Environmental Science & Management, UC Santa Barbara, Santa Barbara, California, USA
| | - Emily C Farrer
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, Louisiana, USA
| | - Julie E Larson
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, Colorado, USA
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA
- USDA Agricultural Research Service, Eastern Oregon Agricultural Research Center, Burns, Oregon, USA
| | - Nancy Shackelford
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA
- School of Environmental Studies, University of Victoria, Victoria, British Columbia, Canada
| | - Marko J Spasojevic
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, Colorado, USA
- Department of Evolution, Ecology, and Organismal Biology, University of California Riverside, Riverside, California, USA
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Valliere JM, Irvine IC, Allen EB. Nitrogen deposition suppresses ephemeral post-fire plant diversity. GLOBAL CHANGE BIOLOGY 2024; 30:e17117. [PMID: 38273574 DOI: 10.1111/gcb.17117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 01/27/2024]
Abstract
Fire is a dominant force shaping patterns of plant diversity in Mediterranean-type ecosystems. In these biodiversity hotspots, including California's endangered coastal scrub, many species remain hidden belowground as seeds and bulbs, only to emerge and flower when sufficient rainfall occurs after wildfire. The unique adaptations possessed by these species enable survival during prolonged periods of unfavorable conditions, but their continued persistence could be threatened by nonnative plant invasion and environmental change. Furthermore, their fleeting presence aboveground makes evaluating these threats in situ a challenge. For example, nitrogen (N) deposition resulting from air pollution is a well-recognized threat to plant diversity worldwide but impacts on fire-following species are not well understood. We experimentally evaluated the impact of N deposition on post-fire vegetation cover and richness for three years in stands of coastal sage scrub that had recently burned in a large wildfire in southern California. We installed plots receiving four levels of N addition that corresponded to the range of N deposition rates in the region. We assessed the impact of pre-fire invasion status on vegetation dynamics by including plots in areas that had previously been invaded by nonnative grasses, as well as adjacent uninvaded areas. We found that N addition reduced native forb cover in the second year post-fire while increasing the abundance of nonnative forbs. As is typical in fire-prone ecosystems, species richness declined over the three years of the study. However, N addition hastened this process, and native forb richness was severely reduced under high N availability, especially in previously invaded shrublands. An indicator species analysis also revealed that six functionally and taxonomically diverse forb species were especially sensitive to N addition. Our results highlight a new potential mechanism for the depletion of native species through the suppression of ephemeral post-fire bloom events.
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Affiliation(s)
- Justin M Valliere
- Department of Plant Sciences, University of California Davis, Davis, California, USA
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, California, USA
| | | | - Edith B Allen
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, California, USA
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3
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Zhang Z, Tang G, Chai X, Liu B, Gao X, Zeng F, Wang Y, Zhang B. Different Responses of Soil Bacterial and Fungal Communities in Three Typical Vegetations following Nitrogen Deposition in an Arid Desert. Microorganisms 2023; 11:2471. [PMID: 37894130 PMCID: PMC10609353 DOI: 10.3390/microorganisms11102471] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/22/2023] [Accepted: 09/29/2023] [Indexed: 10/29/2023] Open
Abstract
The effects of increased nitrogen (N) deposition on desert ecosystems have been extensively studied from a plant community perspective. However, the response of soil microbial communities, which play a crucial role in nutrient cycling, to N inputs and plant community types remains poorly understood. In this study, we conducted a two-year N-addition experiment with five gradients (0, 10, 30, 60, and 120 kg N ha-1 year-1) to evaluate the effect of increased N deposition on soil bacterial and fungal communities in three plant community types, namely, Alhagi sparsifolia Shap., Karelinia caspia (Pall.) Less. monocultures and their mixed community in a desert steppe located on the southern edge of the Taklimakan Desert, Northwest China. Our results indicate that N deposition and plant community types exerted an independent and significant influence on the soil microbial community. Bacterial α-diversity and community dissimilarity showed a unimodal pattern with peaks at 30 and 60 kg N ha-1 year-1, respectively. By contrast, fungal α-diversity and community dissimilarity did not vary significantly with increased N inputs. Furthermore, plant community type significantly altered microbial community dissimilarity. The Mantel test and redundancy analysis indicated that soil pH and total and inorganic N (NH4+ and NO3-) levels were the most critical factors regulating soil microbial communities. Similar to the patterns observed in taxonomic composition, fungi exhibit stronger resistance to N addition compared to bacteria in terms of their functionality. Overall, our findings suggest that the response of soil microbial communities to N deposition is domain-specific and independent of desert plant community diversity, and the bacterial community has a critical threshold under N enrichment in arid deserts.
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Affiliation(s)
- Zhihao Zhang
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; (Z.Z.)
- State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele 848300, China
| | - Gangliang Tang
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; (Z.Z.)
- State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele 848300, China
| | - Xutian Chai
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; (Z.Z.)
- State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele 848300, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bo Liu
- School of Resources and Environment, Linyi University, Linyi 276000, China
| | - Xiaopeng Gao
- Department of Soil Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Fanjiang Zeng
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; (Z.Z.)
- State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele 848300, China
| | - Yun Wang
- Life Science and Technology School, Linnan Normal University, Zhanjiang 524048, China
| | - Bo Zhang
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; (Z.Z.)
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele 848300, China
- National Engineering Technology Research Center for Desert-Oasis Ecological Construction, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
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Andrews HM, Krichels AH, Homyak PM, Piper S, Aronson EL, Botthoff J, Greene AC, Jenerette GD. Wetting-induced soil CO 2 emission pulses are driven by interactions among soil temperature, carbon, and nitrogen limitation in the Colorado Desert. GLOBAL CHANGE BIOLOGY 2023; 29:3205-3220. [PMID: 36907979 DOI: 10.1111/gcb.16669] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 01/20/2023] [Indexed: 05/03/2023]
Abstract
Warming-induced changes in precipitation regimes, coupled with anthropogenically enhanced nitrogen (N) deposition, are likely to increase the prevalence, duration, and magnitude of soil respiration pulses following wetting via interactions among temperature and carbon (C) and N availability. Quantifying the importance of these interactive controls on soil respiration is a key challenge as pulses can be large terrestrial sources of atmospheric carbon dioxide (CO2 ) over comparatively short timescales. Using an automated sensor system, we measured soil CO2 flux dynamics in the Colorado Desert-a system characterized by pronounced transitions from dry-to-wet soil conditions-through a multi-year series of experimental wetting campaigns. Experimental manipulations included combinations of C and N additions across a range of ambient temperatures and across five sites varying in atmospheric N deposition. We found soil CO2 pulses following wetting were highly predictable from peak instantaneous CO2 flux measurements. CO2 pulses consistently increased with temperature, and temperature at time of wetting positively correlated to CO2 pulse magnitude. Experimentally adding N along the N deposition gradient generated contrasting pulse responses: adding N increased CO2 pulses in low N deposition sites, whereas adding N decreased CO2 pulses in high N deposition sites. At a low N deposition site, simultaneous additions of C and N during wetting led to the highest observed soil CO2 fluxes reported globally at 299.5 μmol CO2 m-2 s-1 . Our results suggest that soils have the capacity to emit high amounts of CO2 within small timeframes following infrequent wetting, and pulse sizes reflect a non-linear combination of soil resource and temperature interactions. Importantly, the largest soil CO2 emissions occurred when multiple resources were amended simultaneously in historically resource-limited desert soils, pointing to regions experiencing simultaneous effects of desertification and urbanization as key locations in future global C balance.
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Affiliation(s)
- Holly M Andrews
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, California, USA
| | - Alexander H Krichels
- Department of Environmental Sciences, University of California, Riverside, California, USA
- Center for Conservation Biology, University of California, Riverside, California, USA
| | - Peter M Homyak
- Department of Environmental Sciences, University of California, Riverside, California, USA
| | - Stephanie Piper
- Department of Botany and Plant Sciences, University of California, Riverside, California, USA
| | - Emma L Aronson
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, USA
| | - Jon Botthoff
- Center for Conservation Biology, University of California, Riverside, California, USA
| | - Aral C Greene
- Department of Environmental Sciences, University of California, Riverside, California, USA
| | - G Darrel Jenerette
- Center for Conservation Biology, University of California, Riverside, California, USA
- Department of Botany and Plant Sciences, University of California, Riverside, California, USA
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5
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Püspök JF, Zhao S, Calma AD, Vourlitis GL, Allison SD, Aronson EL, Schimel JP, Hanan EJ, Homyak PM. Effects of experimental nitrogen deposition on soil organic carbon storage in Southern California drylands. GLOBAL CHANGE BIOLOGY 2023; 29:1660-1679. [PMID: 36527334 DOI: 10.1111/gcb.16563] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 11/18/2022] [Indexed: 05/28/2023]
Abstract
Atmospheric nitrogen (N) deposition is enriching soils with N across biomes. Soil N enrichment can increase plant productivity and affect microbial activity, thereby increasing soil organic carbon (SOC), but such responses vary across biomes. Drylands cover ~45% of Earth's land area and store ~33% of global SOC contained in the top 1 m of soil. Nitrogen fertilization could, therefore, disproportionately impact carbon (C) cycling, yet whether dryland SOC storage increases with N remains unclear. To understand how N enrichment may change SOC storage, we separated SOC into plant-derived, particulate organic C (POC), and largely microbially derived, mineral-associated organic C (MAOC) at four N deposition experimental sites in Southern California. Theory suggests that N enrichment increases the efficiency by which microbes build MAOC (C stabilization efficiency) if soil pH stays constant. But if soils acidify, a common response to N enrichment, then microbial biomass and enzymatic organic matter decay may decrease, increasing POC but not MAOC. We found that N enrichment had no effect on C fractions except for a decrease in MAOC at one site. Specifically, despite reported increases in plant biomass in three sites and decreases in microbial biomass and extracellular enzyme activities in two sites that acidified, POC did not increase. Furthermore, microbial C use and stabilization efficiency increased in a non-acidified site, but without increasing MAOC. Instead, MAOC decreased by 16% at one of the sites that acidified, likely because it lost 47% of the exchangeable calcium (Ca) relative to controls. Indeed, MAOC was strongly and positively affected by Ca, which directly and, through its positive effect on microbial biomass, explained 58% of variation in MAOC. Long-term effects of N fertilization on dryland SOC storage appear abiotic in nature, such that drylands where Ca-stabilization of SOC is prevalent and soils acidify, are most at risk for significant C loss.
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Affiliation(s)
- Johann F Püspök
- Department of Environmental Sciences, University of California, Riverside, California, USA
| | - Sharon Zhao
- Department of Environmental Sciences, University of California, Riverside, California, USA
| | - Anthony D Calma
- Department of Environmental Sciences, University of California, Riverside, California, USA
| | - George L Vourlitis
- Department of Biological Sciences, California State University, San Marcos, California, USA
| | - Steven D Allison
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
- Department of Earth System Science, University of California, Irvine, California, USA
| | - Emma L Aronson
- Department of Microbiology and Plant Pathology, University of California, Riverside, California, USA
| | - Joshua P Schimel
- Department of Ecology, Evolution, and Marine Biology and Earth Research Institute, University of California, Santa Barbara, California, USA
| | - Erin J Hanan
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, Nevada, USA
| | - Peter M Homyak
- Department of Environmental Sciences, University of California, Riverside, California, USA
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6
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Wu Z, Jiang X, Chen J, Wang S, Yao C. Geochemistry and release risk for nutrients in lake sediments based on diffusive gradients in thin films. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:40588-40607. [PMID: 36622617 DOI: 10.1007/s11356-022-24961-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 12/20/2022] [Indexed: 01/10/2023]
Abstract
A comprehensive understanding of the mobility of both nitrogen (N) and phosphorus (P) and the inter-relationships between P, N, and iron (Fe) in sediments is important for controlling the "internal loadings" of nutrients in lakes. In this research, diffusive gradients in thin film (DGT) assemblies with binding layers (ZrO-AT, chelex, and ZrO) were designed for PO4-P, Fe, ammonium (NH4-N), and nitrate (NO3-N) at sediment/water interface (SWI) in Western Lake Taihu (China). The biogeochemical processes of N and P related to the physicochemical properties, the dynamic P transfer, the distribution characteristics of P microniches, and the estimation of the release risks in sediments in Western Lake Taihu were simultaneously revealed by the passive sampling technique-DGT with the high spatial resolutions (millimeter and sub-millimeter). Based on DGT concentration (CDGT) related to physicochemical properties in sediments, (1) P biogeochemical reactions included P release from Fe-bound P during Fe reduction, algae biomass decomposition, and phosphatase enzyme activity increased by NH4-N; (2) denitrification and dissimilatory nitrate reduction to ammonium (DNRA) led to exchangeable ammonium (NH4ex) enrichment and NH4-N release; anammox depleted NH4-N transfer; organic matter (OM) mineralization favored NH4-N release; and (3) aerobic nitrification led to NO3-N remobilization; denitrification and DNRA reduced NO3-N release. Redox status, OM, Fe, aluminum, or calcium influenced mobilization of nutrients. The numerical model of DGT-induced fluxes in sediments was used for dynamic P transfers with resupply types ("slow" ~ "fast") controlled by labile P pool, resupply constant, response time, and Dspt rate. The formation of P microniches in two dimensions was revealed. Sediment P release risk index (0.49 ~ 36.85 [lg (nmol cm-3 d-1)]) with "light" ~ "high" risks and diffusive fluxes across SWI (µg m-2 d-1) of 15.0 ~ 639 (PO4-P), - 1403 ~ 5010 (NH4-N), and - 1395 ~ 149 (NO3-N) were derived and lake management strategies were provided. The DGT technique provides the characterization of the mobilization of nutrients and evidence for biogeochemical processes at the fine spatial scales for control of internal loadings in sediments.
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Affiliation(s)
- Zhihao Wu
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China.,State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China
| | - Xia Jiang
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China.,State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China
| | - Junyi Chen
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China.,State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China
| | - Shuhang Wang
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China. .,State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China.
| | - Cheng Yao
- State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China.,College of Water Science, Beijing Normal University, Beijing, 100875, China
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Leaving more than footprints: Anthropogenic nutrient subsidies to a protected area. Ecosphere 2022. [DOI: 10.1002/ecs2.4371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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8
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Zhang X, Song X, Wang T, Huang L, Ma H, Wang M, Tan D. The responses to long-term nitrogen addition of soil bacterial, fungal, and archaeal communities in a desert ecosystem. Front Microbiol 2022; 13:1015588. [PMID: 36312972 PMCID: PMC9606763 DOI: 10.3389/fmicb.2022.1015588] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 09/26/2022] [Indexed: 10/29/2023] Open
Abstract
Nitrogen (N) deposition is a worldwide issue caused by human activity. Long-term deposition of N strongly influences plant productivity and community composition. However, it is still unclear how the microbial community responds to long-term N addition in a desert ecosystem. Therefore, a long-term experiment was conducted in the Gurbantonggut Desert in northwestern China in 2015. Four N addition rates, 0 (CK), 5 (N1), 20 (N2), and 80 (N3) kg N ha-1 yr.-1, were tested and the soil was sampled after 6 years of N addition. High-throughput sequencing (HTS) was used to analyze the soil microbial composition. The HTS results showed that N addition had no significant effect on the bacterial α-diversity and β-diversity (p > 0.05) but significantly reduced the archaeal β-diversity (p < 0.05). The fungal Chao1 and ACE indexes in the N2 treatment increased by 24.10 and 26.07%, respectively. In addition, N addition affected the bacterial and fungal community structures. For example, compared to CK, the relative abundance of Actinobacteria increased by 17.80%, and the relative abundance of Bacteroidetes was reduced by 44.46% under N3 treatment. Additionally, N addition also changed the bacterial and fungal community functions. The N3 treatment showed increased relative abundance of nitrate-reducing bacteria (27.06% higher than CK). The relative abundance of symbiotrophic fungi was increased in the N1 treatment (253.11% higher than CK). SOC and NH4 +-N could explain 62% of the changes in the fungal community function. N addition can directly affect the bacterial community function or indirectly through NO3 --N. These results suggest that different microbial groups may have various responses to N addition. Compared with bacteria and fungi, the effect of N addition was less on the archaeal community. Meanwhile, N-mediated changes of the soil properties play an essential role in changes in the microbial community. The results in the present study provided a reliable basis for an understanding of how the microbial community in a desert ecosystem adapts to long-term N deposition.
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Affiliation(s)
- Xuan Zhang
- College of Life Sciences, Xinjiang Agricultural University, Ürümqi, China
| | - Xin Song
- State Key Laboratory of Grassland Agro-Ecosystems, Institute of Arid Agroecology, College of Ecology, Lanzhou University, Lanzhou, China
| | - Taotao Wang
- College of Life Sciences, Xinjiang Agricultural University, Ürümqi, China
| | - Lei Huang
- College of Life Sciences, Xinjiang Agricultural University, Ürümqi, China
| | - Haiyang Ma
- College of Life Sciences, Xinjiang Agricultural University, Ürümqi, China
| | - Mao Wang
- College of Life Sciences, Xinjiang Agricultural University, Ürümqi, China
| | - Dunyan Tan
- College of Life Sciences, Xinjiang Agricultural University, Ürümqi, China
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Campbell PC, Tong D, Saylor R, Li Y, Ma S, Zhang X, Kondragunta S, Li F. Pronounced increases in nitrogen emissions and deposition due to the historic 2020 wildfires in the western U.S. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 839:156130. [PMID: 35609700 DOI: 10.1016/j.scitotenv.2022.156130] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/16/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
Wildfire outbreaks can lead to extreme biomass burning (BB) emissions of both oxidized (e.g., nitrogen oxides; NOx = NO+NO2) and reduced form (e.g., ammonia; NH3) nitrogen (N) compounds. High N emissions are major concerns for air quality, atmospheric deposition, and consequential human and ecosystem health impacts. In this study, we use both satellite-based observations and modeling results to quantify the contribution of BB to the total emissions, and approximate the impact on total N deposition in the western U.S. Our results show that during the 2020 wildfire season of August-October, BB contributes significantly to the total emissions, with a satellite-derived fraction of NH3 to the total reactive N emissions (median ~ 40%) in the range of aircraft observations. During the peak of the western August Complex Fires in September, BB contributed to ~55% (for the contiguous U.S.) and ~ 83% (for the western U.S.) of the monthly total NOx and NH3 emissions. Overall, there is good model performance of the George Mason University-Wildfire Forecasting System (GMU-WFS) used in this work. The extreme BB emissions lead to significant contributions to the total N deposition for different ecosystems in California, with an average August - October 2020 relative increase of ~78% (from 7.1 to 12.6 kg ha-1 year-1) in deposition rate to major vegetation types (mixed forests + grasslands/shrublands/savanna) compared to the GMU-WFS simulations without BB emissions. For mixed forest types only, the average N deposition rate increases (from 6.2 to 16.9 kg ha-1 year-1) are even larger at ~173%. Such large N deposition due to extreme BB emissions are much (~6-12 times) larger than low-end critical load thresholds for major vegetation types (e.g., forests at 1.5-3 kg ha-1 year-1), and thus may result in adverse N deposition effects across larger areas of lichen communities found in California's mixed conifer forests.
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Affiliation(s)
- Patrick C Campbell
- Center for Spatial Information Science and Systems/Cooperative Institute for Satellite Earth System Studies, George Mason University, Fairfax, VA, USA; Office of Air and Radiation, Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD, USA.
| | - Daniel Tong
- Center for Spatial Information Science and Systems/Cooperative Institute for Satellite Earth System Studies, George Mason University, Fairfax, VA, USA; Department of Atmospheric, Oceanic and Earth Sciences, George Mason University, Fairfax, VA, USA
| | - Rick Saylor
- Office of Air and Radiation, Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, MD, USA
| | - Yunyao Li
- Department of Atmospheric, Oceanic and Earth Sciences, George Mason University, Fairfax, VA, USA
| | - Siqi Ma
- Department of Atmospheric, Oceanic and Earth Sciences, George Mason University, Fairfax, VA, USA
| | - Xiaoyang Zhang
- Geospatial Sciences Center of Excellence, Department of Geography & Geospatial Sciences, South Dakota State University, Brookings, SD, USA
| | - Shobha Kondragunta
- NOAA Satellite Meteorology and Climatology Division, NOAA Air Resources Laboratory, College Park, MD, USA
| | - Fangjun Li
- Geospatial Sciences Center of Excellence, Department of Geography & Geospatial Sciences, South Dakota State University, Brookings, SD, USA
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10
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Syphard AD, Brennan TJ, Rustigian-Romsos H, Keeley JE. Fire-driven vegetation type conversion in Southern California. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2626. [PMID: 35397185 DOI: 10.1002/eap.2626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 01/26/2022] [Accepted: 02/02/2022] [Indexed: 06/14/2023]
Abstract
One consequence of global change causing widespread concern is the possibility of ecosystem conversions from one type to another. A classic example of this is vegetation type conversion (VTC) from native woody shrublands to invasive annual grasslands in the biodiversity hotspot of Southern California. Although the significance of this problem is well recognized, understanding where, how much, and why this change is occurring remains elusive owing to differences in results from studies conducted using different methods, spatial extents, and scales. Disagreement has arisen particularly over the relative importance of short-interval fires in driving these changes. Chronosequence approaches that use space for time to estimate changes have produced different results than studies of changes at a site over time. Here we calculated the percentage woody and herbaceous cover across Southern California using air photos from ~1950 to 2019. We assessed the extent of woody cover change and the relative importance of fire history, topography, soil moisture, and distance to human infrastructure in explaining change across a hierarchy of spatial extents and regions. We found substantial net decline in woody cover and expansion of herbaceous vegetation across all regions, but the most dramatic changes occurred in the northern interior and southern coastal areas. Variables related to frequent, short-interval fire were consistently top ranked as the explanation for shrub to grassland type conversion, but low soil moisture and topographic complexity were also strong correlates. Despite the consistent importance of fire, there was substantial geographical variation in the relative importance of drivers, and these differences resulted in different mapped predictions of VTC. This geographical variation is important to recognize for management decision-making and, in addition to differences in methodological design, may also partly explain differences in previous study results. The overwhelming importance of short-interval fire has management implications. It suggests that actions should be directed away from imposing fires to preventing fires. Prevention can be controlled through management actions that limit ignitions, fire spread, and the damage sustained in areas that do burn. This study also demonstrates significant potential for changing fire regimes to drive large-scale, abrupt ecological change.
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Affiliation(s)
- Alexandra D Syphard
- Conservation Biology Institute, Corvallis, Oregon, USA
- Department of Geography, San Diego State University, San Diego, California, USA
| | - Teresa J Brennan
- USGS Western Ecological Research Center, Three Rivers, California, USA
| | | | - Jon E Keeley
- USGS Western Ecological Research Center, Three Rivers, California, USA
- Department of Ecology & Evolutionary Biology, University of California, Los Angeles, California, USA
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11
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Rong X, Zhou X, Li X, Yao M, Lu Y, Xu P, Yin B, Li Y, Aanderud ZT, Zhang Y. Biocrust diazotrophs and bacteria rather than fungi are sensitive to chronic low N deposition. Environ Microbiol 2022; 24:5450-5466. [PMID: 35844197 DOI: 10.1111/1462-2920.16095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 06/03/2022] [Indexed: 11/03/2022]
Abstract
Anthropogenic long-term nitrogen (N) deposition may dramatically impact biocrusts due to the overarching N limitation of soil biota in deserts. Even low levels of N may reach a critical loading threshold altering biocrust constituents and function. To identify the impact of chronic and continuous low levels of N deposition on biocrusts, we created a realistic gradient mirroring anthropogenic N addition rate (2:1 NH4 + : NO3 - rates: 0.3, 0.5, 1.0, 1.5, 3 g N m-2 yr-1 ) and measured the response of bacteria and fungi within cyanobacterial-dominated biocrusts over 8 years in a temperate desert, the Gurbantunggut Desert, China. We found that once N deposition reached 1.5 g N m-2 yr-1 biocrust bacterial communities, including diazotrophs, were altered while no such tipping point existed for fungi. Above the threshold, bacterial richness was enhanced, the relative abundance of Chloroflexi, FBP and Gemmatimonadetes was elevated, and diazotrophs shifted from being dominated by Nostocaceae and Scytonemataceae (Cyanobacteria) to free-living Bradyrhizobiaceae (Alphaproteobacteria). Alternatively, the relative recovery of a few fungal species within the Lecanorales, Pleosporales and Verrucariales became either enriched or diminished due to N deposition. The chronic addition of N resulted in a dense and interconnected bacterial co-occurrence network that accentuated a functional shift from networks dominated by phototrophic species within the Nostocaceae, Xenococcaceae, Phormidiaceae and Scytonemataceae (Cyanobacteria) to ammonia-oxidizing species within the Nitrosomonadaceae (Betaproteobacteria) and nitrifying bacteria [i.e. Nitrospiraceae (Nitrospirae)]. Based on structural equation models, the effects of N additions on biocrust constituents were imposed through indirect effects on pH, soil electrical conductivity and ammonium concentrations. In summary, biocrust constituents are generally insensitive to chronic low levels of N depositions until rates reach above 1.5 g N m-2 yr-1 with diazotrophs being the most sensitive biocrust constituents followed by bacteria and finally fungi. Ultimately once the threshold is reached N deposition favours biocrust constituents utilizing inorganic N and other C sources over relying on phototrophic and/or N-fixing cyanobacteria for C and N.
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Affiliation(s)
- Xiaoying Rong
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Xiaobing Zhou
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Xiangzhen Li
- Key Laboratory of Environmental and Applied Microbiology, Chinese Academy of Sciences, and Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Minjie Yao
- College of Resources and Environment, Fujian Agriculture and Forest University, Fuzhou, China
| | - Yongxing Lu
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.,University of the Chinese Academy of Sciences, Beijing, China
| | - Peng Xu
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.,University of the Chinese Academy of Sciences, Beijing, China
| | - Benfeng Yin
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Yonggang Li
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Zachary T Aanderud
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah, USA
| | - Yuanming Zhang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
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12
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Wilkins K, Clark C, Aherne J. Ecological thresholds under atmospheric nitrogen deposition for 1200 herbaceous species and 24 communities across the United States. GLOBAL CHANGE BIOLOGY 2022; 28:2381-2395. [PMID: 34986509 PMCID: PMC9770646 DOI: 10.1111/gcb.16076] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 11/26/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
Nitrogen (N) emissions and atmospheric deposition have increased significantly during the last century and become a stressor for many N-sensitive plant species. Understanding individual and community herbaceous plant species thresholds to atmospheric N deposition can inform emissions reduction policy. Here, we present results using Threshold Indicator Taxa Analysis (TITAN) applied to more than 1200 unique plant species and 24 vegetation communities (i.e., alliances) across the United States (US) to assess vulnerability to N deposition. Alliance-level thresholds (change points) for species decreasing in abundance along the gradient ranged from 1.8 to 14.3 kg N ha─1 year─1 and tended to be lower in the west than the east, which suggests that eastern communities, where N deposition has been historically higher, may have already lost many sensitive species. For the species that were present in more than one alliance, over half had a variable response to the N deposition gradient, suggesting that local factors affect vulnerability. Significant progress has been made during the past 30 years to reduce N emissions, which has reduced the percentage of plots at risk to N deposition from 72% to 35%. Nevertheless, over a third of plots remain at risk, and an average reduction of N deposition of 20% would protect half of the plots where N deposition exceeds community thresholds. Furthermore, the alliance- and species-level change points determined in this study may be used to inform N critical loads.
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Affiliation(s)
- Kayla Wilkins
- School of the Environment, Trent University, Peterborough, Ontario, Canada
| | - Christopher Clark
- Integrated Environmental Assessment Branch, US Environmental Protection Agency, Washington, DC, USA
| | - Julian Aherne
- School of the Environment, Trent University, Peterborough, Ontario, Canada
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13
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Tropospheric and Surface Nitrogen Dioxide Changes in the Greater Toronto Area during the First Two Years of the COVID-19 Pandemic. REMOTE SENSING 2022. [DOI: 10.3390/rs14071625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We present tropospheric nitrogen dioxide (NO2) changes observed by the Canadian Pandora measurement program in the Greater Toronto Area (GTA), Canada, and compare the results with surface NO2 concentrations measured via in situ instruments to assess the local emission changes during the first two years of the COVID-19 pandemic. In the City of Toronto, the first lockdown period started on 15 March 2020, and continued until 24 June 2020. ECMWF Reanalysis v5 (ERA-5) wind information was used to facilitate the data analysis and reveal detailed local emission changes from different areas of the City of Toronto. Evaluating seven years of Pandora observations, a clear NO2 reduction was found, especially from the more polluted downtown Toronto and airport areas (e.g., declined by 35% to 40% in 2020 compared to the 5-year mean value from these areas) during the first two years of the pandemic. Compared to the sharp decline in NO2 emissions in 2020, the atmospheric NO2 levels in 2021 started to recover, but are still below the mean values in pre-pandemic time. For some sites, the pre-pandemic NO2 local morning rush hour peak has still not returned in 2021, indicating a change in local traffic and commuter patterns. The long-term (12 years) surface air quality record shows a statistically significant decline in NO2 with and without April to September 2020 observations (trend of −4.1%/yr and −3.9%/yr, respectively). Even considering this long-term negative trend in NO2, the observed NO2 reduction (from both Pandora and in situ) in the early stage of the pandemic is still statistically significant. By implementing the new wind-based validation method, the high-resolution satellite instrument (TROPOMI) can also capture the local NO2 emission pattern changes to a good level of agreement with the ground-based observations. The bias between ground-based and satellite observations during the pandemic was found to have a positive shift (5–12%) than the bias during the pre-pandemic period.
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14
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Wendlandt CE, Gano-Cohen KA, Stokes PJN, Jonnala BNR, Zomorrodian AJ, Al-Moussawi K, Sachs JL. Wild legumes maintain beneficial soil rhizobia populations despite decades of nitrogen deposition. Oecologia 2022; 198:419-430. [PMID: 35067801 DOI: 10.1007/s00442-022-05116-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 01/10/2022] [Indexed: 10/19/2022]
Abstract
Natural landscapes are increasingly impacted by nitrogen enrichment from aquatic and airborne pollution sources. Nitrogen enrichment in the environment can eliminate the net benefits that plants gain from nitrogen-fixing microbes such as rhizobia, potentially altering host-mediated selection on nitrogen fixation. However, we know little about the long-term effects of nitrogen enrichment on this critical microbial service. Here, we sampled populations of the legume Acmispon strigosus and its associated soil microbial communities from sites spanning an anthropogenic nitrogen deposition gradient. We measured the net growth benefits plants obtained from their local soil microbial communities and quantified plant investment into nodules that house nitrogen-fixing rhizobia. We found that plant growth benefits from sympatric soil microbes did not vary in response to local soil nitrogen levels, and instead varied mainly among plant lines. Soil nitrogen levels positively predicted the number of nodules formed on sympatric plant hosts, although this was likely due to plant genotypic variation in nodule formation, rather than variation among soil microbial communities. The capacity of all the tested soil microbial communities to improve plant growth is consistent with plant populations imposing strong selection on rhizobial nitrogen fixation despite elevated soil nitrogen levels, suggesting that host control traits in A. strigosus are stable under long-term nutrient enrichment.
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Affiliation(s)
- Camille E Wendlandt
- Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA
| | - Kelsey A Gano-Cohen
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, 92521, USA
| | - Peter J N Stokes
- Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA
| | - Basava N R Jonnala
- Department of Evolution, Ecology and Organismal Biology, University of California, Riverside, CA, 92521, USA
| | - Avissa J Zomorrodian
- Department of Evolution, Ecology and Organismal Biology, University of California, Riverside, CA, 92521, USA
| | - Khadija Al-Moussawi
- Department of Evolution, Ecology and Organismal Biology, University of California, Riverside, CA, 92521, USA
| | - Joel L Sachs
- Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA. .,Department of Microbiology and Plant Pathology, University of California, Riverside, CA, 92521, USA. .,Department of Evolution, Ecology and Organismal Biology, University of California, Riverside, CA, 92521, USA.
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15
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Geiser LH, Root H, Smith RJ, Jovan SE, St Clair L, Dillman KL. Lichen-based critical loads for deposition of nitrogen and sulfur in US forests. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 291:118187. [PMID: 34563846 DOI: 10.1016/j.envpol.2021.118187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/08/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Critical loads are thresholds of atmospheric deposition below which harmful ecological effects do not occur. Because lichens are sensitive to atmospheric deposition, lichen-based critical loads can foreshadow changes of other forest processes. Here, we derive critical loads of nitrogen (N) and sulfur (S) deposition for continental US and coastal Alaskan forests, based on nationally consistent lichen community surveys at 8855 sites. Across the eastern and western US ranges of 459 lichen species, each species' realized optimum was the N or S atmospheric deposition value at which it most frequently occurred. The mean of optima for all species at a site, weighted by their abundances, was defined as a community "airscore" indicative of species' collective responses to atmospheric deposition. To determine critical loads for adverse community compositional shifts, we then modeled changes in airscores as a function of deposition, climate and forest habitat predictors in nonparametric multiplicative regression. Critical loads, indicative of initial shifts from pollution-sensitive toward pollution-tolerant species, occurred at 1.5 kg N ha-1 y-1 and 2.7 kg S ha-1 y-1. Importantly, these critical loads remain constant under any climate regime nationwide, suggesting both simplicity and nationwide applicability. Our models predict that preventing excess N deposition of just 0.2-2.0 kg ha-1 y-1 in the next century could offset the detrimental effects of predicted climate warming on lichen communities. Because excess deposition and climate warming both harm the most ecologically influential species, keeping conditions below critical loads would sustain both forest ecosystem functioning and climate resilience.
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Affiliation(s)
- Linda H Geiser
- USDA Forest Service, Biological and Physical Resources, Washington, DC, USA
| | | | - Robert J Smith
- USDA Forest Service, Biological and Physical Resources, Washington, DC, USA.
| | - Sarah E Jovan
- USDA Forest Service, Pacific Northwest Research Station, Portland, OR, USA
| | - Larry St Clair
- M.L. Bean Life Science Museum and Department of Biology, Brigham Young University, Provo, UT, USA
| | - Karen L Dillman
- USDA Forest Service, Biological and Physical Resources, Washington, DC, USA
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16
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Questad EJ, Fitch RL, Paolini J, Hernández E, Suding KN. Nitrogen addition, not heterogeneity, alters the relationship between invasion and native decline in California grasslands. Oecologia 2021; 197:651-660. [PMID: 34642816 DOI: 10.1007/s00442-021-05049-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 09/26/2021] [Indexed: 11/29/2022]
Abstract
The presence of invasive species reduces the growth and performance of native species; however, the linear or non-linear relationships between invasive abundance and native population declines are less often studied. We examine how the amount and spatial distribution of experimental N deposition influences the relationship between non-native, invasive annual grass abundance (Bromus hordeaceus and Bromus diandrus) and a dominant, native perennial grass species (Stipa pulchra) in California. We hypothesized that native populations would decline as invasion increased, and that high nitrogen availability would cause native species to decline at lower invasion levels. We predicted that the rate of population decline would be slower in heterogeneous, compared to homogeneous, environments. We employed a field experiment that manipulated the amount and spatial heterogeneity of N addition across a range of invasive/native-dominated communities. There were strong negative and non-linear associations between level of invasion and S. pulchra proportional change (PC). Stipa pulchra PC was more negative and seedling survival was lower when N was added, and the negative effects of N addition on PC became larger in the final year of the study when S. pulchra had the largest declines. There was not strong evidence showing reduced competition in heterogeneous, compared to homogeneous, N treatments. Soil moisture was similar between S. pulchra and B. hordeaceus plots under ambient N, but B. hordeaceus under added N reduced soil moisture. Under N addition, Bromus spp. take up N earlier, reduce soil moisture, and create dry conditions in which S. pulchra declines.
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Affiliation(s)
- Erin J Questad
- Biological Sciences Department, California State Polytechnic University, Pomona, 3801 W Temple Ave, Pomona, CA, 91768, USA.
| | - Robert L Fitch
- Biological Sciences Department, California State Polytechnic University, Pomona, 3801 W Temple Ave, Pomona, CA, 91768, USA.,Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, 5221 Cheadle Hall, Santa Barbara, CA, 93106, USA
| | - Joshua Paolini
- Biological Sciences Department, California State Polytechnic University, Pomona, 3801 W Temple Ave, Pomona, CA, 91768, USA
| | - Eliza Hernández
- Biological Sciences Department, California State Polytechnic University, Pomona, 3801 W Temple Ave, Pomona, CA, 91768, USA.,Environmental Studies Program, University of Oregon, 1585 E 13th Ave, Eugene, OR, 97403, USA
| | - Katharine N Suding
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80303, USA
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17
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Zhihao W, Xia J, Shuhang W, Li Z, Lixin J, Junyi C, Qing C, Kun W, Cheng Y. Mobilization and geochemistry of nutrients in sediment evaluated by diffusive gradients in thin films: Significance for lake management. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 292:112770. [PMID: 34020304 DOI: 10.1016/j.jenvman.2021.112770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 04/29/2021] [Accepted: 05/04/2021] [Indexed: 06/12/2023]
Abstract
Investigation of in-situ mobilization of both nitrogen (N) and phosphate (PO43-) in sediment is important for lake management strategy. In this paper, diffusion gradients in thin films (DGT) and DGT induced flux in sediments (DIFS) model are newly designed for in-situ measurement of iron (Fe), PO43-, nitrate (NO3-N) and ammonium (NH4-N), and nutrients' mobility in sediment in Lake Nanhu (China). According to DGT profiles together with physicochemical properties in sediment, (I) PO43- is released from (i) Fe-bound P plus loosely sorbed P in anoxic sediment and (ii) the loosely sorbed P in oxic sediment; (II) anoxic sediment inhibits nitrification and NO3-N release, but it favors denitrification and dissimilatory nitrate reduction to ammonium (DNRA), leading to NH4-N release; (III) Eh and organic matter are two key influence factors on mobility of PO43-, NO3-N and NH4-N. According to DIFS calculation, the dynamics of desorption and diffusion at two sites belong to (i) slow rate of resupply and (ii) fast resupply cases, respectively. Internal loadings are estimated to be 92.74 (PO43-), 268.1 (NH4-N) and -2466 kg a-1 (NO3-N), which reflects sediment mainly acts as a source for PO43- and NH4-N, and a sink for NO3-N in water. Based on sediment P release risk index (SPRRI), P release risks in lake sediments are estimated, ranging from light to relative high level. DGT and SPRRI aid choice of restoration methods for sediment, including sediment dredging, phytoremediation and in-situ inactivation.
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Affiliation(s)
- Wu Zhihao
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China; State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China
| | - Jiang Xia
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China; State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China
| | - Wang Shuhang
- National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China; State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China.
| | - Zhao Li
- State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China
| | - Jiao Lixin
- State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China
| | - Chen Junyi
- State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China
| | - Cai Qing
- State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China
| | - Wang Kun
- State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China
| | - Yao Cheng
- State Environmental Protection Key Laboratory for Lake Pollution Control, Institute of Lake Environment, Chinese Research Academy of Environmental Sciences (CRAES), Beijing, 100012, China; College of Water Science, Beijing Normal University, Beijing, 100875, China
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18
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Davies KW, Leger EA, Boyd CS, Hallett LM. Living with exotic annual grasses in the sagebrush ecosystem. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 288:112417. [PMID: 33765575 DOI: 10.1016/j.jenvman.2021.112417] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
Exotic annual grasses dominate millions of hectares and increase fire frequency in the sagebrush ecosystem of North America. This devastating invasion is so costly and challenging to revegetate with perennial vegetation that restoration efforts need to be prioritized and strategically implemented. Management needs to break the annual grass-fire cycle and prevent invasion of new areas, while research is needed to improve restoration success. Under current land management and climate regimes, extensive areas will remain annual grasslands, because of their expansiveness and the low probability of transition to perennial dominance. We propose referring to these communities as Intermountain West Annual Grasslands, recognizing that they are a stable state and require different management goals and objectives than perennial-dominated systems. We need to learn to live with annual grasslands, reducing their costs and increasing benefits derived from them, at the same time maintaining landscape-level plant diversity that could allow transition to perennial dominance under future scenarios. To accomplish this task, we propose a framework and research to improve our ability to live with exotic annual grasses in the sagebrush biome.
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Affiliation(s)
- Kirk W Davies
- Eastern Oregon Agricultural Research Center, USDA-Agricultural Research Service, 67826-A Hwy 205, Burns, OR, 97720, USA.
| | - Elizabeth A Leger
- Department of Biology, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV, 89557, USA
| | - Chad S Boyd
- Eastern Oregon Agricultural Research Center, USDA-Agricultural Research Service, 67826-A Hwy 205, Burns, OR, 97720, USA
| | - Lauren M Hallett
- Department of Biology and Environmental Studies Program, University of Oregon, 12010 University of Oregon, Eugene, OR, 97405, USA
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19
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Klimczyk M, Siczek A, Schimmelpfennig L. Improving the efficiency of urea-based fertilization leading to reduction in ammonia emission. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 771:145483. [PMID: 33736136 DOI: 10.1016/j.scitotenv.2021.145483] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/15/2021] [Accepted: 01/24/2021] [Indexed: 06/12/2023]
Abstract
A problematic issue in agriculture is the high quantity of ammonia being released resulting in a partial loss of the nitrogen which is contained in urea fertilizers. Alignment with European Union legislation on the regulation of ammonia emission from mineral fertilizers after 2030, urea fertilizers with reduced ammonia emissions by at least 30% will be allowed to remain in use. Currently, laboratory and field tests are carried out to assess the effectiveness of inhibiting nitrogen losses from urea fertilizers. Both urease and nitrification inhibitors are tested. The best results were noticed for the urease inhibitor - NBPT (N-(n-Butyl) thiophosphoric triamide) that can reduce ammonia emissions from urea fertilizers by 30-70% in both laboratory and field tests. The addition of NBPT to the UAN (urea ammonium nitrate solution) fertilizer allowed for the reduction of ammonia emission by 50%. Combining nitrification inhibitors with urease inhibitors may lead to an increase in ammonia emission because they prolong the retention time of ammonium ions in soil, which are the precursors in the process of ammonia emission. In order to meet the imposed requirements under field conditions, in addition factors such as: dose and date of application, method of application, type of soil cultivation, its type and pH and atmospheric conditions should be considered. This review gives an overview of the factors influencing the efficiency of nitrogen use from urea-based fertilizers, taking into account the effectiveness of modified fertilizers (with urease and nitrification inhibitors) in reduction of ammonia emissions.
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Affiliation(s)
- Marta Klimczyk
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland; Grupa Azoty Zakłady Azotowe "Puławy" S.A., Tysiąclecia Państwa Polskiego 13, 24-110 Puławy, Poland
| | - Anna Siczek
- Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland.
| | - Lech Schimmelpfennig
- Grupa Azoty Zakłady Azotowe "Puławy" S.A., Tysiąclecia Państwa Polskiego 13, 24-110 Puławy, Poland
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20
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Green L, Magel C, Brown C. Management pathways for the successful reduction of nonpoint source nutrients in coastal ecosystems. REGIONAL STUDIES IN MARINE SCIENCE 2021; 45:1-15. [PMID: 35800159 PMCID: PMC9257601 DOI: 10.1016/j.rsma.2021.101851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Eutrophication remains a threat to coastal habitats and water quality worldwide. The U.S. Clean Water Act resulted in reductions of nutrient loading from point sources but management of nonpoint sources (NPS) of nutrients remains challenging despite efforts over at least three decades. The hydrological factors, best management practices (BMPs) and regulatory mechanisms that target nutrient NPS and improve coastal ecosystem function are poorly understood. We identified three case study sites in the U.S. with sufficient NPS management and monitoring history to quantify changes in estuarine habitat and water quality following BMP implementation and regulation targeting nutrient NPS. Utilizing publicly available data, we compared sites that are geographically distant and hydrologically distinct. We found that BMPs targeting NPS loads from surface waters into Roberts Bay (Florida) and Newport Bay (California) significantly reduced nutrient concentrations and harmful algal blooms within ~20 years. Improvements occurred despite concurrent human population growth within both watersheds. Conversely, we found that the majority of BMPs implemented within the Peconic Estuary (New York) watershed targeted surface waters despite a dominance of nitrogen inputs (97%) from groundwater and atmospheric sources. Declines in habitat and water quality in Peconic Estuary may be due to a failure to control the dominant nutrient sources and the long residence time of nitrogen in groundwater. Compared to surface water, reducing groundwater and atmospheric nutrients face greater technical and financial challenges. Improvements to Peconic Estuary may occur with further reductions in surface water inputs and as nutrients leach out of the groundwater. Although the effectiveness of specific NPS BMPs has been examined at small spatial scales, our study is the first to quantify improvements at a watershed scale. We showed that successful NPS management pathways are those which targeted the dominant sources of nutrients to coastal ecosystems and applied multiple BMPs within watersheds.
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Affiliation(s)
- Lauri Green
- Current Address: Bloomsburg University, 400 East Second Street, Bloomsburg, PA, 17815
- U.S. Environmental Protection Agency 2111 SE Marine Science Center Drive, Newport, OR, 97366
| | - Caitlin Magel
- Current Address: Puget Sound Institute, University of Washington Tacoma, 326 East D Street, Tacoma, WA 98421
- U.S. Environmental Protection Agency 2111 SE Marine Science Center Drive, Newport, OR, 97366
| | - Cheryl Brown
- U.S. Environmental Protection Agency 2111 SE Marine Science Center Drive, Newport, OR, 97366
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21
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Rangeland Land-Sharing, Livestock Grazing’s Role in the Conservation of Imperiled Species. SUSTAINABILITY 2021. [DOI: 10.3390/su13084466] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Land sharing, conserving biodiversity on productive lands, is globally promoted. Much of the land highest in California’s biodiversity is used for livestock production, providing an opportunity to understand land sharing and species conservation. A review of United States Fish and Wildlife Service listing documents for 282 threatened and endangered species in California reveals a complex and varied relationship between grazing and conservation. According to these documents, 51% or 143 of the federally listed animal and plant species are found in habitats with grazing. While livestock grazing is a stated threat to 73% (104) of the species sharing habitat with livestock, 59% (85) of the species are said to be positively influenced, with considerable overlap between species both threatened and benefitting from grazing. Grazing is credited with benefiting flowering plants, mammals, insects, reptiles, amphibians, fish, crustaceans, and bird species by managing the state’s novel vegetation and providing and maintaining habitat structure and ecosystem functions. Benefits are noted for species across all of California’s terrestrial habitats, except alpine, and for some aquatic habitats, including riparian, wetlands, and temporary pools. Managed grazing can combat anthropomorphic threats, such as invasive species and nitrogen deposition, supporting conservation-reliant species as part of land sharing.
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22
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Wheeler MM, Collins SL, Grimm NB, Cook EM, Clark C, Sponseller RA, Hall SJ. Water and nitrogen shape winter annual plant diversity and community composition in near‐urban Sonoran Desert preserves. ECOL MONOGR 2021; 91:1-19. [DOI: 10.1002/ecm.1450] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Megan M. Wheeler
- School of Life Sciences Arizona State University P.O. Box 874501 Tempe Arizona 85287‐4501 USA
| | - Scott L. Collins
- Department of Biology University of New Mexico 1 University of New Mexico MSC03 2020 Albuquerque New Mexico 87131‐0001 USA
| | - Nancy B. Grimm
- School of Life Sciences Arizona State University P.O. Box 874501 Tempe Arizona 85287‐4501 USA
| | - Elizabeth M. Cook
- Department of Environmental Science Barnard College 3009 Broadway New York City New York 10027 USA
| | - Christopher Clark
- U.S. Environmental Protection Agency Office of Research and Development 1200 Pennsylvania Avenue Washington D.C. 20004 USA
| | - Ryan A. Sponseller
- Department of Ecology and Environmental Sciences Umeå University SE‐ 901 87 Umeå Sweden
| | - Sharon J. Hall
- School of Life Sciences Arizona State University P.O. Box 874501 Tempe Arizona 85287‐4501 USA
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23
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Vourlitis GL, Jaureguy J, Marin L, Rodriguez C. Shoot and root biomass production in semi-arid shrublands exposed to long-term experimental N input. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 754:142204. [PMID: 33254913 DOI: 10.1016/j.scitotenv.2020.142204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/28/2020] [Accepted: 09/02/2020] [Indexed: 06/12/2023]
Abstract
Anthropogenic nitrogen (N) deposition has affected the primary production of terrestrial ecosystems worldwide; however, ecosystem responses often vary over time because of transient responses, interactions between N, precipitation, and/or other nutrients, and changes in plant species composition. Here we report N-induced changes in above- and below-ground standing crop and production over an 11-year period for two semi-arid shrublands, chaparral and coastal sage scrub (CSS), of Southern California. Shrubs were exposed to 50 kgN ha-1 in the fall of each year to simulate the accumulation of dry N deposition, and shoot and root biomass and leaf area index (LAI) were measured every 3 months to assess how biomass production responded to chronic, dry N inputs. N inputs significantly altered above- and below-ground standing crop, production, and LAI; however, N impacts varied over time. For chaparral, N inputs initially increased root production but suppressed shoot production; however, over time biomass partitioning reversed and plants exposed to N had significantly more shoot biomass. In CSS, N inputs caused aboveground production to increase only during wet years, and this interaction between added N and precipitation was due in part to a highly flexible growth response of CSS shrubs to increases in N and water availability and to a shift from slower-growing native shrubs to fast-growing introduced annuals. Together, these results indicate that long-term N inputs will lead to complex, spatially and temporally variable growth responses for these, and similar, Mediterranean-type shrublands.
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Affiliation(s)
- George L Vourlitis
- Department of Biological Sciences, California State University, San Marcos, CA 92064, United States of America.
| | - Jeff Jaureguy
- Department of Biological Sciences, California State University, San Marcos, CA 92064, United States of America
| | - Leticia Marin
- Department of Biological Sciences, California State University, San Marcos, CA 92064, United States of America
| | - Charlton Rodriguez
- Department of Biological Sciences, California State University, San Marcos, CA 92064, United States of America
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Phillips ML, Winkler DE, Reibold RH, Osborne BB, Reed SC. Muted responses to chronic experimental nitrogen deposition on the Colorado Plateau. Oecologia 2021; 195:513-524. [PMID: 33415421 DOI: 10.1007/s00442-020-04841-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/17/2020] [Indexed: 10/22/2022]
Abstract
Anthropogenic nitrogen (N) deposition is significantly altering both community structure and ecosystem processes in terrestrial ecosystems across the globe. However, our understanding of the consequences of N deposition in dryland systems remains relatively poor, despite evidence that drylands may be particularly vulnerable to increasing N inputs. In this study, we investigated the influence of 7 years of multiple levels of simulated N deposition (0, 2, 5, and 8 kg N ha-1 year-1) on plant community structure and biological soil crust (biocrust) cover at three semi-arid grassland sites spanning a soil texture gradient. Biocrusts are a surface community of mosses, lichens, cyanobacteria, and/or algae, and have been shown to be sensitive to N inputs. We hypothesized that N additions would decrease plant diversity, increase abundance of the invasive annual grass Bromus tectorum, and decrease biocrust cover. Contrary to our expectations, we found that N additions did not affect plant diversity or B. tectorum abundance. In partial support of our hypotheses, N additions negatively affected biocrust cover in some years, perhaps driven in part by inter-annual differences in precipitation. Soil inorganic N concentrations showed rapid but ephemeral responses to N additions and plant foliar N concentrations showed no response, indicating that the magnitude of plant and biocrust responses to N fertilization may be buffered by endogenous N cycling. More work is needed to determine N critical load thresholds for plant community and biocrust dynamics in semi-arid systems and the factors that determine the fate of N inputs.
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Affiliation(s)
- Michala L Phillips
- Southwest Biological Science Center, U.S. Geological Survey, Moab, UT, USA.
| | - Daniel E Winkler
- Southwest Biological Science Center, U.S. Geological Survey, Moab, UT, USA
| | - Robin H Reibold
- Southwest Biological Science Center, U.S. Geological Survey, Moab, UT, USA
| | - Brooke B Osborne
- Southwest Biological Science Center, U.S. Geological Survey, Moab, UT, USA
| | - Sasha C Reed
- Southwest Biological Science Center, U.S. Geological Survey, Moab, UT, USA
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25
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Valliere JM, Bucciarelli GM, Bytnerowicz A, Fenn ME, Irvine IC, Johnson RF, Allen EB. Declines in native forb richness of an imperiled plant community across an anthropogenic nitrogen deposition gradient. Ecosphere 2020. [DOI: 10.1002/ecs2.3032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Justin M. Valliere
- Department of Botany and Plant Sciences University of California Riverside Riverside California 92521 USA
| | - Gary M. Bucciarelli
- Department of Ecology and Evolutionary Biology University of California Los Angeles Los Angeles California 90095 USA
| | - Andrzej Bytnerowicz
- Pacific Southwest Research Station United States Forest Service Riverside California 92507 USA
| | - Mark E. Fenn
- Pacific Southwest Research Station United States Forest Service Riverside California 92507 USA
| | - Irina C. Irvine
- Santa Monica Mountains National Recreation Area National Park Service Thousand Oaks California 91360 USA
| | - Robert F. Johnson
- Center for Conservation Biology University of California Riverside Riverside California92521USA
| | - Edith B. Allen
- Department of Botany and Plant Sciences University of California Riverside Riverside California 92521 USA
- Center for Conservation Biology University of California Riverside Riverside California92521USA
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26
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Walker JT, Beachley G, Zhang L, Benedict KB, Sive BC, Schwede DB. A review of measurements of air-surface exchange of reactive nitrogen in natural ecosystems across North America. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 698:133975. [PMID: 31499348 PMCID: PMC7032654 DOI: 10.1016/j.scitotenv.2019.133975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 08/16/2019] [Accepted: 08/17/2019] [Indexed: 04/13/2023]
Abstract
This review summarizes the state of the science of measurements of dry deposition of reactive nitrogen (Nr) compounds in North America, beginning with current understanding of the importance of dry deposition at the U.S. continental scale followed by a review of micrometeorological flux measurement methods. Measurements of Nr air-surface exchange in natural ecosystems of North America are then summarized, focusing on the U.S. and Canada. Drawing on this synthesis, research needed to address the incompleteness of dry deposition budgets, more fully characterize temporal and geographical variability of fluxes, and better understand air-surface exchange processes is identified. Our assessment points to several data and knowledge gaps that must be addressed to advance dry deposition budgets and air-surface exchange modeling for North American ecosystems. For example, recent studies of particulate (NO3-) and gaseous (NOx, HONO, peroxy nitrates) oxidized N fluxes challenge the fundamental framework of unidirectional flux from the atmosphere to the surface employed in most deposition models. Measurements in forest ecosystems document the importance of in-canopy chemical processes in regulating the net flux between the atmosphere and biosphere, which can result in net loss from the canopy. These results emphasize the need for studies to quantify within- and near-canopy sources and sinks of the full suite of components of the Nr chemical system under study (e.g., NOy or HNO3-NH3-NH4NO3). With respect to specific ecosystems and geographical locations, additional flux measurements are needed particularly in agricultural regions (NH3), coastal zones (NO3- and organic N), and arid ecosystems and along urban to rural gradients (NO2). Measurements that investigate non-stomatal exchange processes (e.g., deposition to wet surfaces) and the biogeochemical drivers of bidirectional exchange (e.g., NH3) are considered high priority. Establishment of long-term sites for process level measurements of reactive chemical fluxes should be viewed as a high priority long-term endeavor of the atmospheric chemistry and ecological communities.
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Affiliation(s)
- John T Walker
- U.S. EPA, Office of Research and Development, Durham, NC, USA.
| | | | - Leiming Zhang
- Environment and Climate Change Canada, Toronto, Ontario, Canada
| | - Katherine B Benedict
- Colorado State University, Department of Atmospheric Science, Fort Collins, CO, USA
| | - Barkley C Sive
- National Park Service, Air Resources Division, Lakewood, CO, USA
| | - Donna B Schwede
- U.S. EPA, Office of Research and Development, Durham, NC, USA
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27
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Phillips ML, McNellis BE, Allen MF, Allen EB. Differences in root phenology and water depletion by an invasive grass explains persistence in a Mediterranean ecosystem. AMERICAN JOURNAL OF BOTANY 2019; 106:1210-1218. [PMID: 31502242 DOI: 10.1002/ajb2.1344] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 07/15/2019] [Indexed: 06/10/2023]
Abstract
PREMISE Flexible phenological responses of invasive plants under climate change may increase their ability to establish and persist. A key aspect of plant phenology is the timing of root production, how it coincides with canopy development and subsequent water-use. The timing of these events within species and across communities could influence the invasion process. We examined above- and belowground phenology of two species in southern California, the native shrub, Adenostoma fasciculatum, and the invasive perennial grass, Ehrharta calycina to investigate relative differences in phenology and water use. METHODS We used normalized difference vegetation index (NDVI) to track whole-canopy activity across the landscape and sap flux sensors on individual chaparral shrubs to assess differences in aboveground phenology of both species. To determine differences in belowground activity, we used soil moisture sensors, minirhizotron imagery, and stable isotopes. RESULTS The invasive grass depleted soil moisture earlier in the spring and produced longer roots at multiple depths earlier in the growing season than the native shrub. However, Adenostoma fasciculatum produced longer roots in the top 10 cm of soil profile in May. Aboveground activity of the two species peaked at the same time. CONCLUSIONS The fact that Ehrharta calycina possessed longer roots earlier in the season suggests that invasive plants may gain a competitive edge over native plants through early activity, while also depleting soil moisture earlier in the season. Depletion of soil moisture earlier by E. calycina suggests that invasive grasses could accelerate the onset of the summer drought in chaparral systems, assuring their persistence following invasion.
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Affiliation(s)
- Michala L Phillips
- Department of Botany and Plant Sciences, University of California Riverside, 900 University Ave., Riverside, California, 92521, USA
| | - Brandon E McNellis
- Department of Forest, Rangeland and Fire Sciences, University of Idaho, Moscow, Idaho, 83844, USA
| | - Michael F Allen
- Department of Microbiology and Plant Pathology, University of California Riverside, 900 University Ave., Riverside, California, 92521, USA
| | - Edith B Allen
- Department of Botany and Plant Sciences, University of California Riverside, 900 University Ave., Riverside, California, 92521, USA
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28
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Weiss SB. Dead flowers. NATURE PLANTS 2019; 5:654-655. [PMID: 31263242 DOI: 10.1038/s41477-019-0424-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- Stuart B Weiss
- Creekside Center for Earth Observation, Menlo Park, CA, USA.
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29
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Syphard AD, Brennan TJ, Keeley JE. Extent and drivers of vegetation type conversion in Southern California chaparral. Ecosphere 2019. [DOI: 10.1002/ecs2.2796] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
- Alexandra D. Syphard
- Conservation Biology Institute 136 SW Washington Avenue, Suite 202 Corvallis Oregon 97333 USA
- Sage Underwriters 4250 Executive Square, Suite 900 La Jolla California 92037 USA
| | | | - Jon E. Keeley
- USGS Western Ecological Research Center Three Rivers California USA
- Department of Ecology & Evolutionary Biology University of California Los Angeles California USA
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30
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Nielsen RL, James JJ, Drenovsky RE. Functional Traits Explain Variation in Chaparral Shrub Sensitivity to Altered Water and Nutrient Availability. FRONTIERS IN PLANT SCIENCE 2019; 10:505. [PMID: 31057595 PMCID: PMC6482203 DOI: 10.3389/fpls.2019.00505] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
Worldwide drylands are threatened by changes in resource availability associated with global environmental change. Functional traits may help predict which species will be most responsive to these alterations in nutrient and water availability. Current functional trait work focuses on tissue construction and nutrient concentrations, but plant performance in low resource environments also may be strongly influenced by traits related to nutrient budgets and allocation. Our overall objective was to compare trait responses in a suite of serpentine and nonserpentine congener pairs from the California chaparral, a biodiverse region facing nutrient deposition and future changes in precipitation. In a common garden greenhouse environment, we grew small plants of Arctostaphylos manzanita, A. viscida, Ceanothus cuneatus, C. jepsonii, Quercus berberidifolia, and Q. durata in contrasting soil nutrient and moisture treatments. We measured a suite of traits representing physiological, growth, and mineral nutrient responses to these treatments. Overall, plant growth rate and leaf-level phosphorus use efficiency were greatest in the low water, high nutrient treatment, and lowest in the high water, low nutrient treatment. Variation in growth rate and plasticity among species and treatments was primarily associated with differences in mineral nutrition-based traits as opposed to differences in biomass allocation or specific leaf area. Namely, faster growing species and species with greater plasticity allocated more nitrogen and phosphorous to leaves and demonstrated greater photosynthetic phosphorus use efficiency. Overall, nonserpentine species had greater plasticity and biomass response to resource addition than serpentine species, and congener pairs responded to these resource additions more similarly to each other than species across congener pairs. This study extends our general understanding of how functional traits may influence species responses to environmental change and highlights the need to integrate mineral nutrition-based traits, including allocation of nutrient pools and nutrient use efficiency into this larger trait framework. Ultimately, this insight can help identify, in part, why coexisting species may vary in sensitivity to anthropogenic driven changes in soil resource availability.
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Affiliation(s)
- Reina L. Nielsen
- Biology Department, John Carroll University, University Heights, OH, United States
| | - Jeremy J. James
- Sierra Foothills Research and Extension Center, Browns Valley, CA, United States
| | - Rebecca E. Drenovsky
- Biology Department, John Carroll University, University Heights, OH, United States
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31
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Cui X, Yue P, Wu W, Gong Y, Li K, Misselbrook T, Goulding K, Liu X. The Growth and N Retention of Two Annual Desert Plants Varied Under Different Nitrogen Deposition Rates. FRONTIERS IN PLANT SCIENCE 2019; 10:356. [PMID: 30972090 PMCID: PMC6443888 DOI: 10.3389/fpls.2019.00356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 03/07/2019] [Indexed: 06/09/2023]
Abstract
Nitrogen (N) partitioning between plant and soil pools is closely related to biomass accumulation and allocation, and is of great importance for quantifying the biomass dynamics and N fluxes of ecosystems, especially in low N-availability desert ecosystems. However, partitioning can differ among species even when growing in the same habitat. To better understand the variation of plant biomass allocation and N retention within ephemeral and annual species we studied the responses of Malcolmia Africana (an ephemeral) and Salsola affinis (an annual) to N addition, including plant growth, N retention by the plant and soil, and N lost to the environment using 15N (double-labeled 15NH4 15NO3 (5.16% abundance) added at 0, 0.8, 1.6, 3.2, and 6.4 g pot-1, equivalent to 0, 15, 30, 60, and 120 kg N ha-1) in a pot experiment. Higher N addition (N120) inhibited plant growth and biomass accumulation of the ephemeral but not the annual. In addition, the aboveground:belowground partitioning of N (the R:S ratio) of the ephemeral decreased with increasing N addition, but that of the annual increased. The N input corresponding to maximum biomass and 15N retention of the ephemeral was significantly less than that of the annual. The aboveground and belowground retention of N in the ephemeral were significantly less than those of the annual, except at low N rates. The average plant-soil system recovery of added 15N by the ephemeral was 70%, significantly higher than that of the annual with an average of 50%. Although the whole plant-soil 15N recovery of this desert ecosystem decreased with increasing N deposition, our results suggested that it may vary with species composition and community change under future climate and elevated N deposition.
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Affiliation(s)
- Xiaoqing Cui
- Key Laboratory of Plant-Soil Interactions of the Ministry of Education, Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
- Sino-France Institute of Earth Systems Science, Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Ping Yue
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi, China
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Wenchao Wu
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
| | - Yanming Gong
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi, China
| | - Kaihui Li
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi, China
| | - Tom Misselbrook
- Department of Sustainable Soils and Grassland Systems, Rothamsted Research, Devon, United Kingdom
| | - Keith Goulding
- Department of Sustainable Soils and Grassland Systems, Rothamsted Research, Harpenden, United Kingdom
| | - Xuejun Liu
- Key Laboratory of Plant-Soil Interactions of the Ministry of Education, Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
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32
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Gravuer K, Gennet S, Throop HL. Organic amendment additions to rangelands: A meta-analysis of multiple ecosystem outcomes. GLOBAL CHANGE BIOLOGY 2019; 25:1152-1170. [PMID: 30604474 PMCID: PMC6849820 DOI: 10.1111/gcb.14535] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/03/2018] [Accepted: 11/01/2018] [Indexed: 05/06/2023]
Abstract
Interest in land application of organic amendments-such as biosolids, composts, and manures-is growing due to their potential to increase soil carbon and help mitigate climate change, as well as to support soil health and regenerative agriculture. While organic amendments are predominantly applied to croplands, their application is increasingly proposed on relatively arid rangelands that do not typically receive fertilizers or other inputs, creating unique concerns for outcomes such as native plant diversity and water quality. To maximize environmental benefits and minimize potential harms, we must understand how soil, water, and plant communities respond to particular amendments and site conditions. We conducted a global meta-analysis of 92 studies in which organic amendments had been added to arid, semiarid, or Mediterranean rangelands. We found that organic amendments, on average, provide some environmental benefits (increased soil carbon, soil water holding capacity, aboveground net primary productivity, and plant tissue nitrogen; decreased runoff quantity), as well as some environmental harms (increased concentrations of soil lead, runoff nitrate, and runoff phosphorus; increased soil CO2 emissions). Published data were inadequate to fully assess impacts to native plant communities. In our models, adding higher amounts of amendment benefitted four outcomes and harmed two outcomes, whereas adding amendments with higher nitrogen concentrations benefitted two outcomes and harmed four outcomes. This suggests that trade-offs among outcomes are inevitable; however, applying low-N amendments was consistent with both maximizing benefits and minimizing harms. Short study time frames (median 1-2 years), limited geographic scope, and, for some outcomes, few published studies limit longer-term inferences from these models. Nevertheless, they provide a starting point to develop site-specific amendment application strategies aimed toward realizing the potential of this practice to contribute to climate change mitigation while minimizing negative impacts on other environmental goals.
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Affiliation(s)
- Kelly Gravuer
- Center for Biodiversity OutcomesArizona State UniversityTempeArizona
- The Nature ConservancyArlingtonVirginia
| | | | - Heather L. Throop
- School of Earth and Space ExplorationArizona State UniversityTempeArizona
- School of Life SciencesArizona State UniversityTempeArizona
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33
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Bytnerowicz A, Fenn ME, Cisneros R, Schweizer D, Burley J, Schilling SL. Nitrogenous air pollutants and ozone exposure in the central Sierra Nevada and White Mountains of California - Distribution and evaluation of ecological risks. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 654:604-615. [PMID: 30447599 DOI: 10.1016/j.scitotenv.2018.11.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/30/2018] [Accepted: 11/01/2018] [Indexed: 06/09/2023]
Abstract
Ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2), nitric acid (HNO3), and ozone (O3) were measured in summers of 2012 and 2013 with passive samplers. Nine monitoring sites were on W-E transect (511 to 3490 m) across central Sierra Nevada Mountains (SNM), and five sites on elevational gradient (1237 to 4346 m) in White Mountains (WM) of California. Levels of pollutants were similar in 2012 and 2013 in all sites. NH3, NO2, and HNO3 were highest near highly polluted Central Valley of California (CVC): maximum summer season means 7.8 μg m-3, 3.0 ppb, and 3.0 μg m-3, respectively. Regional background for NH3, NO2, and HNO3 in SNM occurred >20 km from CVC and >1500 m with seasonal averages: 2.1-4.8 μg m-3; 0.8-1.7 ppb; 1.0-1.8 μg m-3, respectively, during two seasons. Levels of NH3, NO2, and HNO3 in WM remote locations were similar: 1.2-3.3 μg m-3, 0.6-1.1 ppb, and 1.0-1.3 μg m-3, respectively. Seasonal mean O3 (38-60 ppb) in SNM did not change with distance from CVC nor elevation. In WM, O3 and NO mixing ratios were 41-61 ppb and 2.3-4.1 ppb, respectively, increasing with elevation. Even the lowest NH3 concentrations determined in this study were higher than NH3 continental background. This fact, as well as high values of Nreduced/Noxidized near CVC of 1.9 in 2012 and 2.0 in 2013, decreasing with distance to 0.7 in 2012 and 0.8 in 2013, show importance of NH3 emissions from CVC as a contributor to N deposition and ecological impacts in SNM. The phytotoxic O3 indices, AOT40 and W126, for selected sites on SNM and WM transects, showed high potential for negative O3 impacts on vegetation, including forest trees. CAPSULE: Elevated NH3, NO2, and HNO3 on the western slopes of the Sierra Nevada Mountains (SNM) near the Central Valley of California (CVC) decreased with distance from CVC and elevation to regional background levels also recorded at high elevation sites of the White Mountains (WM).
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Affiliation(s)
- Andrzej Bytnerowicz
- USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA
| | - Mark E Fenn
- USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA.
| | | | - Donald Schweizer
- USDA Forest Service, Inyo National Forest, 351 Pacu Lane, Suite 200, Bishop, CA 93514, USA
| | - Joel Burley
- Saint Mary's College of California, Moraga, CA, USA
| | - Susan L Schilling
- USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA
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Stewart JAE, Butterfield HS, Richmond JQ, Germano DJ, Westphal MF, Tennant EN, Sinervo B. Habitat restoration opportunities, climatic niche contraction, and conservation biogeography in California's San Joaquin Desert. PLoS One 2019; 14:e0210766. [PMID: 30645624 PMCID: PMC6333358 DOI: 10.1371/journal.pone.0210766] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 12/31/2018] [Indexed: 12/03/2022] Open
Abstract
A recent global trend toward retirement of farmland presents opportunities to reclaim habitat for threatened and endangered species. We examine habitat restoration opportunities in one of the world's most converted landscapes, California's San Joaquin Desert (SJD). Despite the presence of 35 threatened and endangered species, agricultural expansion continues to drive habitat loss in the SJD, even as marginal farmland is retired. Over the next decades a combination of factors, including salinization, climate change, and historical groundwater overdraft, are projected to lead to the retirement of more than 2,000 km2 of farmland in the SJD. To promote strategic habitat protection and restoration, we conducted a quantitative assessment of habitat loss and fragmentation, habitat suitability, climatic niche stability, climate change impacts, habitat protection, and reintroduction opportunities for an umbrella species of the SJD, the endangered blunt-nosed leopard lizard (Gambelia sila). We use our suitability models, in conjunction with modern and historical land use maps, to estimate the historical and modern rate of habitat loss to development. The estimated amount of habitat lost since the species became protected under endangered species law in 1967 is greater than the total amount of habitat currently protected through public ownership and conservation easement. We document climatic niche contraction and associated range contraction away from the more mesic margins of the species' historical distribution, driven by the anthropogenic introduction of exotic grasses and forbs. The impact of exotic species on G. sila range dynamics appears to be still unfolding. Finally, we use NASA fallowed area maps to identify 610 km2 of fallowed or retired agricultural land with high potential to again serve as habitat. We discuss conservation strategies in light of the potential for habitat restoration and multiple drivers of ongoing and historical habitat loss.
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Affiliation(s)
- Joseph A. E. Stewart
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, United States of America
- Institute for the Study of Ecological and Evolutionary Climate Impacts, University of California, Santa Cruz, CA, United States of America
| | | | | | - David J. Germano
- Department of Biology, California State University Bakersfield, Bakersfield, CA, United States of America
| | | | - Erin N. Tennant
- Lands Unit, Central Region, California Department of Fish and Wildlife, Fresno, CA, United States of America
| | - Barry Sinervo
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, United States of America
- Institute for the Study of Ecological and Evolutionary Climate Impacts, University of California, Santa Cruz, CA, United States of America
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Sickman JO, James AE, Fenn ME, Bytnerowicz A, Lucero DM, Homyak PM. Quantifying atmospheric N deposition in dryland ecosystems: A test of the Integrated Total Nitrogen Input (ITNI) method. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 646:1253-1264. [PMID: 30235611 DOI: 10.1016/j.scitotenv.2018.07.320] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 07/21/2018] [Accepted: 07/23/2018] [Indexed: 06/08/2023]
Abstract
Estimating nitrogen (N) deposition to terrestrial ecosystems is complicated by the multiple forms and routes of N loading from the atmosphere. We used the integrated total nitrogen input (ITNI) method, which is based on the principle of isotope dilution within a plant-liquid-sand system, to quantify N inputs to coastal sage scrub ecosystems in Riverside, California. Using the ITNI method, we measured atmospheric N deposition of 29.3 kg N ha-1 yr-1 over a range of aboveground plant biomass of 228 to 424 g m-2. From 85 to 96% of the atmospheric N inputs were taken up by plants in the ITNI modules with most of the assimilation mediated by, and stored in, aboveground biomass. Parallel measurements using conventional approaches yielded deposition rates of 25.2 kg N ha-1 yr-1 when using the inferential method and 4.8 kg N ha-1 yr-1 using throughfall collectors. The relatively low throughfall estimates were attributed to canopy retention of inorganic N, low rainfall, and to the fact that the throughfall flux data did not include organic N and stomatal uptake of N gases. Also, during dry periods, frequent watering of ITNI modules may have increased stomatal conductance and led to overestimates of N deposition. Across published studies that used the ITNI method, areal N deposition rates varied by ~40-fold, were positively correlated with plant biomass and 90% of the variability in measured deposition rates can be explained by plant biomass production. The ITNI method offers a holistic approach to measuring atmospheric N deposition in arid ecosystems, although more study is needed to understand how watering rates effect N deposition measurements.
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Affiliation(s)
- James O Sickman
- Department of Environmental Sciences, University of California, Riverside, CA 92521, USA.
| | - Amanda E James
- Department of Environmental Sciences, University of California, Riverside, CA 92521, USA
| | - Mark E Fenn
- Pacific Southwest Research Station, USFS, 4955 Canyon Crest Dr., Riverside, CA 92507, USA
| | - Andrzej Bytnerowicz
- Pacific Southwest Research Station, USFS, 4955 Canyon Crest Dr., Riverside, CA 92507, USA
| | - Delores M Lucero
- Department of Environmental Sciences, University of California, Riverside, CA 92521, USA
| | - Peter M Homyak
- Department of Environmental Sciences, University of California, Riverside, CA 92521, USA
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Pinho P, Dias T, Cordovil CMDS, Dragosits U, Dise NB, Sutton MA, Branquinho C. Mapping Portuguese Natura 2000 sites in risk of biodiversity change caused by atmospheric nitrogen pollution. PLoS One 2018; 13:e0198955. [PMID: 29927996 PMCID: PMC6013174 DOI: 10.1371/journal.pone.0198955] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 05/28/2018] [Indexed: 11/17/2022] Open
Abstract
In this paper, we assess and map the risk that atmospheric nitrogen (atN) pollution poses to biodiversity in Natura 2000 sites in mainland Portugal. We first review the ecological impacts of atN pollution on terrestrial ecosystems, focusing on the biodiversity of Natura 2000 sites. These nature protection sites, especially those located within the Mediterranean Basin, are under-characterized regarding the risk posed by atN pollution. We focus on ammonia (NH3) because this N form is mostly associated with agriculture, which co-occurs at or in the immediate vicinity of most areas of conservation interest in Portugal. We produce a risk map integrating NH3 emissions and the susceptibility of Natura 2000 sites to atN pollution, ranking habitat sensitivity to atN pollution using expert knowledge from a panel of Portuguese ecological and habitat experts. Peats, mires, bogs, and similar acidic and oligotrophic habitats within Natura 2000 sites (most located in the northern mountains) were assessed to have the highest relative risk of biodiversity change due to atN pollution, whereas Natura 2000 sites in the Atlantic and Mediterranean climate zone (coastal, tidal, and scrubland habitats) were deemed the least sensitive. Overall, results allowed us to rank all Natura 2000 sites in mainland Portugal in order of evaluated risk posed by atN pollution. The approach is of great relevance for stakeholders in different countries to help prioritize site protection and to define research priorities. This is especially relevant in countries with a lack of expertise to assess the impacts of nitrogen on biodiversity and can represent an important step up from current knowledge in such countries.
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Affiliation(s)
- Pedro Pinho
- cE3c, Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
- CERENA, Centro de Recursos Naturais e Ambiente, Instituto Superior Técnico, Universidade de Lisboa, Portugal
| | - Teresa Dias
- cE3c, Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | | | - Ulrike Dragosits
- NERC Centre for Ecology & Hydrology (CEH), Edinburgh Research Station, Bush Estate, Penicuik, Midlothian, United Kingdom
| | - Nancy B. Dise
- NERC Centre for Ecology & Hydrology (CEH), Edinburgh Research Station, Bush Estate, Penicuik, Midlothian, United Kingdom
| | - Mark A. Sutton
- NERC Centre for Ecology & Hydrology (CEH), Edinburgh Research Station, Bush Estate, Penicuik, Midlothian, United Kingdom
| | - Cristina Branquinho
- cE3c, Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
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Zhou X, Bowker MA, Tao Y, Wu L, Zhang Y. Chronic nitrogen addition induces a cascade of plant community responses with both seasonal and progressive dynamics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 626:99-108. [PMID: 29335179 DOI: 10.1016/j.scitotenv.2018.01.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 01/03/2018] [Accepted: 01/04/2018] [Indexed: 05/22/2023]
Abstract
Short-lived herbaceous plants provide a useful model to rapidly reveal how multiple generations of plants in natural plant communities of sensitive desert ecosystems will be affected by N deposition. We monitored dynamic responses of community structure, richness, evenness, density and biomass of herbaceous plants to experimental N addition (2:1 NH4+:NO3- added at 0, 0.5, 1, 3, 6 and 24gNm-2a-1) in three seasons in each of three years in the Gurbantunggut desert, a typical temperate desert of central Asia. We found clear rate-dependent and season-dependent effects of N deposition on each of these variables, in most cases becoming more obvious through time. N addition reduced plant richness, leading to a loss of about half of the species after three generations in the highest N application level. Evenness and density were relatively insensitive to all but the greatest levels of N addition for two generations, but negative effects emerged in the third generation. Biomass, both above and below ground, was non-linearly affected by N deposition. Low and intermediate levels of N deposition often increased biomass, whereas the highest level suppressed biomass. Stimulatory effects of intermediate N addition disappeared in the third generation. All of these responses are strongly interrelated in a cascade of changes. Notably, changes in biomass due to N deposition were mediated by declines in richness and evenness, and other changes in community structure, rather than solely being the direct outcome of release from limitation. The interrelationships between N deposition and the different plant community attributes change not only seasonally, but also progressively change through time. These temporal changes appear to be largely independent of interannual or seasonal climatic conditions.
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Affiliation(s)
- Xiaobing Zhou
- Xinjiang Institute of Ecology and Geography, Key Laboratory of Biogeography and Bioresources in Arid Land, Chinese Academy of Sciences, Urumqi 830011, China.
| | - Matthew A Bowker
- School of Forestry, Northern Arizona University, Flagstaff, AZ 86011, USA.
| | - Ye Tao
- Xinjiang Institute of Ecology and Geography, Key Laboratory of Biogeography and Bioresources in Arid Land, Chinese Academy of Sciences, Urumqi 830011, China
| | - Lin Wu
- Xinjiang Institute of Ecology and Geography, Key Laboratory of Biogeography and Bioresources in Arid Land, Chinese Academy of Sciences, Urumqi 830011, China
| | - Yuanming Zhang
- Xinjiang Institute of Ecology and Geography, Key Laboratory of Biogeography and Bioresources in Arid Land, Chinese Academy of Sciences, Urumqi 830011, China.
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Fenn ME, Bytnerowicz A, Schilling SL, Vallano DM, Zavaleta ES, Weiss SB, Morozumi C, Geiser LH, Hanks K. On-road emissions of ammonia: An underappreciated source of atmospheric nitrogen deposition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 625:909-919. [PMID: 29996462 DOI: 10.1016/j.scitotenv.2017.12.313] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/26/2017] [Accepted: 12/27/2017] [Indexed: 05/26/2023]
Abstract
UNLABELLED We provide updated spatial distribution and inventory data for on-road NH3 emissions for the continental United States (U.S.) On-road NH3 emissions were determined from on-road CO2 emissions data and empirical NH3:CO2 vehicle emissions ratios. Emissions of NH3 from on-road sources in urbanized regions are typically 0.1-1.3tkm-2yr-1 while NH3 emissions in agricultural regions generally range from 0.4-5.5tkm-2yr-1, with a few hotspots as high as 5.5-11.2tkm-2yr-1. Counties with higher vehicle NH3 emissions than from agriculture include 40% of the U.S. POPULATION The amount of wet inorganic N deposition as NH4+ from the National Atmospheric Deposition Program (NADP) network ranged from 37 to 83% with a mean of 58.7%. Only 4% of the NADP sites across the U.S. had <45% of the N deposition as NH4+ based on data from 2014 to 2016, illustrating the near-universal elevated proportions of NH4+ in deposition across the U.S. Case studies of on-road NH3 emissions in relation to N deposition include four urban sites in Oregon and Washington where the average NH4-N:NO3-N ratio in bulk deposition was 2.3. At urban sites in the greater Los Angeles Basin, bulk deposition of NH4-N and NO3-N were equivalent, while NH4-N:NO3-N in throughfall under shrubs ranged from 0.6 to 1.7. The NH4-N:NO3-N ratio at 7-10 sites in the Lake Tahoe Basin averaged 1.4 and 1.6 in bulk deposition and throughfall, and deposition of NH4-N was strongly correlated with summertime NH3 concentrations. On-road emissions of NH3 should not be ignored as an important source of atmospheric NH3, as a major contributor to particulate air pollution, and as a driver of N deposition in urban and urban-affected regions.
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Affiliation(s)
- Mark E Fenn
- USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA.
| | - Andrzej Bytnerowicz
- USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA
| | - Susan L Schilling
- USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA
| | - Dena M Vallano
- Environmental Studies Department, University of California, Santa Cruz, CA 95064, USA
| | - Erika S Zavaleta
- Environmental Studies Department, University of California, Santa Cruz, CA 95064, USA
| | - Stuart B Weiss
- Creekside Center for Earth Observations, Menlo Park, CA 94025, USA
| | - Connor Morozumi
- Environmental Studies Department, University of California, Santa Cruz, CA 95064, USA
| | - Linda H Geiser
- U.S. Forest Service, Watershed, Fish, Wildlife, Air & Rare Plants, 201 14th Street SW, Washington, DC 20250, USA
| | - Kenneth Hanks
- USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA
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CLARK CHRISTOPHERM, PHELAN JENNIFER, DORAISWAMY PRAKASH, BUCKLEY JOHN, CAJKA JAMESC, DENNIS ROBINL, LYNCH JASON, NOLTE CHRISTOPHERG, SPERO TANYAL. Atmospheric deposition and exceedances of critical loads from 1800-2025 for the conterminous United States. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:978-1002. [PMID: 29714821 PMCID: PMC8637495 DOI: 10.1002/eap.1703] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 12/09/2017] [Accepted: 12/21/2017] [Indexed: 05/26/2023]
Abstract
Atmospheric deposition of nitrogen (N) and sulfur (S) has increased dramatically over pre-industrial levels, with many potential impacts on terrestrial and aquatic ecosystems. Quantitative thresholds, termed "critical loads" (CLs), have been developed to estimate the deposition rate above which damage is thought to occur. However, there remains no comprehensive comparison of when, where, and over what time periods individual CLs have been exceeded. We addressed this knowledge gap by combining several published data sources for historical and contemporary deposition, and overlaying these on six CL types from the National Critical Loads Database (NCLDv2.5; terrestrial acidification, aquatic acidification, lichen, nitrate leaching, plant community composition, and forest-tree health) to examine exceedances from 1800 to 2011. We expressed CLs as the minimum, 10th, and 50th percentiles within 12-km grid cells. Minimum CLs were relatively uniform across the country (200-400 eq·ha-1 ·yr-1 ), and have been exceeded for decades beginning in the early 20th century. The area exceeding minimum CLs peaked in the 1970s and 1980s, exposing 300,000 to 3 million km2 (depending on the CL type) to harmful levels of deposition, with a total area exceeded of 5.8 million km2 (~70% of the conterminous United States). Since then, deposition levels have dropped, especially for S, with modest reductions in exceedance by 2011 for all CL types, totaling 5.2 million km2 in exceedance. The 10th and 50th percentile CLs followed similar trends, but were not consistently available at the 12-km grid scale. We also examined near-term future deposition and exceedances in 2025 under current air quality regulations, and under various scenarios of climate change and additional nitrogen management controls. Current regulations were projected to reduce exceedances of any CL from 5.2 million km2 in 2011 to 4.8 million km2 in 2025. None of the additional N management or climate scenarios significantly affected areal exceedances, although exceedance severity declined. In total, it is clear that many CLs have been exceeded for decades, and are likely to remain so in the short term under current policies. Additionally, we suggest many areas for improvement to enhance our understanding of deposition and its effects to support informed decision making.
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Affiliation(s)
- CHRISTOPHER M. CLARK
- U.S. Environmental Protection Agency (8623-P), Office of Research and Development, National Center for Environmental Assessment, 1200 Pennsylvania Ave NW, Washington DC 20460 USA
| | - JENNIFER PHELAN
- RTI International, 3040 East Cornwallis Rd., P.O. Box 12194, Research Triangle Park, NC 27709 USA
| | - PRAKASH DORAISWAMY
- RTI International, 3040 East Cornwallis Rd., P.O. Box 12194, Research Triangle Park, NC 27709 USA
| | - JOHN BUCKLEY
- RTI International, 3040 East Cornwallis Rd., P.O. Box 12194, Research Triangle Park, NC 27709 USA
| | - JAMES C. CAJKA
- RTI International, 3040 East Cornwallis Rd., P.O. Box 12194, Research Triangle Park, NC 27709 USA
| | - ROBIN L. DENNIS
- Retired. U.S. Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, NC 27709 USA
| | - JASON LYNCH
- U.S. Environmental Protection Agency, Office of Atmospheric Programs, 1200 Pennsylvania Ave NW, Washington DC 20460 USA
| | - CHRISTOPHER G. NOLTE
- U.S. Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, NC 27709 USA
| | - TANYA L. SPERO
- U.S. Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, NC 27709 USA
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40
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Kimball S, Principe Z, Deutschman D, Strahm S, Huxman TE, Lulow M, Balazs K. Resistance and resilience: ten years of monitoring shrub and prairie communities in Orange County,
CA
,
USA. Ecosphere 2018. [DOI: 10.1002/ecs2.2212] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Sarah Kimball
- Center for Environmental Biology UC Irvine Irvine California 92697 USA
| | - Zachary Principe
- The Nature Conservancy 402 W Broadway #1350 San Diego California 92101 USA
| | - Douglas Deutschman
- San Diego State University 5500 Campanile Dr San Diego California 92182 USA
| | - Spring Strahm
- San Diego State University 5500 Campanile Dr San Diego California 92182 USA
| | - Travis E. Huxman
- Center for Environmental Biology UC Irvine Irvine California 92697 USA
| | - Megan Lulow
- UCI NATURE UC Irvine Irvine California 92697 USA
| | - Kathleen Balazs
- Center for Environmental Biology UC Irvine Irvine California 92697 USA
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41
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Meza-Lopez MM, Mooney KA, Thompson AL, Ho NK, Pratt JD. A test for clinal variation in Artemisia californica and associated arthropod responses to nitrogen addition. PLoS One 2018; 13:e0191997. [PMID: 29390030 PMCID: PMC5794083 DOI: 10.1371/journal.pone.0191997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 01/15/2018] [Indexed: 11/18/2022] Open
Abstract
The response of plant traits to global change is of fundamental importance to understanding anthropogenic impacts on natural systems. Nevertheless, little is known about plant genetic variation in such responses or the indirect effect of environmental change on higher trophic levels. In a three-year common garden experiment, we grew the shrub Artemisia californica from five populations sourced along a 700 km latitudinal gradient under ambient and nitrogen (N) addition (20 kg N ha-1) and measured plant traits and associated arthropods. N addition increased plant biomass to a similar extent among all populations. In contrast, N addition effects on most other plant traits varied among plant populations; N addition reduced specific leaf area and leaf percent N and increased carbon to nitrogen ratios in the two northern populations, but had the opposite or no effect on the three southern populations. N addition increased arthropod abundance to a similar extent among all populations in parallel with an increase in plant biomass, suggesting that N addition did not alter plant resistance to herbivores. N addition had no effect on arthropod diversity, richness, or evenness. In summary, genetic variation among A. californica populations mediated leaf-trait responses to N addition, but positive direct effects of N addition on plant biomass and indirect effects on arthropod abundance were consistent among all populations.
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Affiliation(s)
- Maria M. Meza-Lopez
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, United States of America
| | - Kailen A. Mooney
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, United States of America
| | - Amanda L. Thompson
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, United States of America
| | - Nicole K. Ho
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, United States of America
| | - Jessica D. Pratt
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, United States of America
- * E-mail:
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Park IW, Hooper J, Flegal JM, Jenerette GD. Impacts of climate, disturbance and topography on distribution of herbaceous cover in Southern California chaparral: Insights from a remote‐sensing method. DIVERS DISTRIB 2018. [DOI: 10.1111/ddi.12693] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- Isaac W. Park
- Department of Botany & Plant Sciences University of California at Riverside Riverside CA USA
- Center for Conservation Biology University of California at Riverside Riverside CA USA
| | | | - James M. Flegal
- Department of Statistics University of California at Riverside Riverside CA USA
| | - G. Darrel Jenerette
- Department of Botany & Plant Sciences University of California at Riverside Riverside CA USA
- Center for Conservation Biology University of California at Riverside Riverside CA USA
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43
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Chaparral Landscape Conversion in Southern California. SPRINGER SERIES ON ENVIRONMENTAL MANAGEMENT 2018. [DOI: 10.1007/978-3-319-68303-4_12] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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44
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Fusaro L, Palma A, Salvatori E, Basile A, Maresca V, Asadi Karam E, Manes F. Functional indicators of response mechanisms to nitrogen deposition, ozone, and their interaction in two Mediterranean tree species. PLoS One 2017; 12:e0185836. [PMID: 28973038 PMCID: PMC5626521 DOI: 10.1371/journal.pone.0185836] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 09/20/2017] [Indexed: 11/18/2022] Open
Abstract
The effects of nitrogen (N) deposition, tropospheric ozone (O3) and their interaction were investigated in two Mediterranean tree species, Fraxinus ornus L. (deciduous) and Quercus ilex L. (evergreen), having different leaf habits and resource use strategies. An experiment was conducted under controlled condition to analyse how nitrogen deposition affects the ecophysiological and biochemical traits, and to explore how the nitrogen-induced changes influence the response to O3. For both factors we selected realistic exposures (20 kg N ha-1 yr-1 and 80 ppb h for nitrogen and O3, respectively), in order to elucidate the mechanisms implemented by the plants. Nitrogen addition resulted in higher nitrogen concentration at the leaf level in F. ornus, whereas a slight increase was detected in Q. ilex. Nitrogen enhanced the maximum rate of assimilation and ribulose 1,5-bisphosphate regeneration in both species, whereas it influenced the light harvesting complex only in the deciduous F. ornus that was also affected by O3 (reduced assimilation rate and accelerated senescence-related processes). Conversely, Q. ilex developed an avoidance mechanism to cope with O3, confirming a substantial O3 tolerance of this species. Nitrogen seemed to ameliorate the harmful effects of O3 in F. ornus: the hypothesized mechanism of action involved the production of nitrogen oxide as the first antioxidant barrier, followed by enzymatic antioxidant response. In Q. ilex, the interaction was not detected on gas exchange and photosystem functionality; however, in this species, nitrogen might stimulate an alternative antioxidant response such as the emission of volatile organic compounds. Antioxidant enzyme activity was lower in plants treated with both O3 and nitrogen even though reactive oxygen species production did not differ between the treatments.
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Affiliation(s)
- Lina Fusaro
- Sapienza University of Rome, Department of Environmental Biology, Rome, Italy
| | - Adriano Palma
- Sapienza University of Rome, Department of Environmental Biology, Rome, Italy
| | | | - Adriana Basile
- University of Naples “Federico II”, Biology Department, Naples, Italy
| | - Viviana Maresca
- University of Naples “Federico II”, Biology Department, Naples, Italy
| | - Elham Asadi Karam
- Shahid Bahonar University of Kerman, Biology Department, Kerman, Iran
| | - Fausto Manes
- Sapienza University of Rome, Department of Environmental Biology, Rome, Italy
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Valliere JM, Irvine IC, Santiago L, Allen EB. High N, dry: Experimental nitrogen deposition exacerbates native shrub loss and nonnative plant invasion during extreme drought. GLOBAL CHANGE BIOLOGY 2017; 23:4333-4345. [PMID: 28319292 DOI: 10.1111/gcb.13694] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 02/13/2017] [Indexed: 05/21/2023]
Abstract
Hotter, longer, and more frequent global change-type drought events may profoundly impact terrestrial ecosystems by triggering widespread vegetation mortality. However, severe drought is only one component of global change, and ecological effects of drought may be compounded by other drivers, such as anthropogenic nitrogen (N) deposition and nonnative plant invasion. Elevated N deposition, for example, may reduce drought tolerance through increased plant productivity, thereby contributing to drought-induced mortality. High N availability also often favors invasive, nonnative plant species, and the loss of woody vegetation due to drought may create a window of opportunity for these invaders. We investigated the effects of multiple levels of simulated N deposition on a Mediterranean-type shrubland plant community in southern California from 2011 to 2016, a period coinciding with an extreme, multiyear drought in the region. We hypothesized that N addition would increase native shrub productivity, but that this would increase susceptibility to drought and result in increased shrub loss over time. We also predicted that N addition would favor nonnatives, especially annual grasses, leading to higher biomass and cover of these species. Consistent with these hypotheses, we found that high N availability increased native shrub canopy loss and mortality, likely due to the higher productivity and leaf area and reduced water-use efficiency we observed in shrubs subject to N addition. As native shrub cover declined, we also observed a concomitant increase in cover and biomass of nonnative annuals, particularly under high levels of experimental N deposition. Together, these results suggest that the impacts of extended drought on shrubland ecosystems may be more severe under elevated N deposition, potentially contributing to the widespread loss of native woody species and vegetation-type conversion.
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Affiliation(s)
- Justin M Valliere
- Department of Botany and Plant Sciences and Center for Conservation Biology, University of California Riverside, Riverside, CA, USA
| | - Irina C Irvine
- Santa Monica Mountains National Recreation Area, U.S. National Park Service, Thousand Oaks, CA, USA
| | - Louis Santiago
- Department of Botany and Plant Sciences and Center for Conservation Biology, University of California Riverside, Riverside, CA, USA
| | - Edith B Allen
- Department of Botany and Plant Sciences and Center for Conservation Biology, University of California Riverside, Riverside, CA, USA
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Clark CM, Bell MD, Boyd JW, Compton JE, Davidson EA, Davis C, Fenn ME, Geiser L, Jones L, Blett TF. Nitrogen‐induced terrestrial eutrophication: cascading effects and impacts on ecosystem services. Ecosphere 2017. [DOI: 10.1002/ecs2.1877] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Christopher M. Clark
- National Center for Environmental Assessment Office of Research and Development U.S. EPA Washington D.C. 20460 USA
| | - Michael D. Bell
- Air Resources Division National Park Service Lakewood Colorado 80225 USA
| | | | - Jana E. Compton
- Western Ecology Division Office of Research and Development U.S. EPA Corvallis Oregon 97333 USA
| | - Eric A. Davidson
- Appalachian Laboratory University of Maryland Center for Environmental Science Frostburg Maryland 21532 USA
| | - Christine Davis
- Office of Air and Radiation, Office of Air Quality Planning and Standards U.S. EPA Research Triangle Park North Carolina 27709 USA
| | - Mark E. Fenn
- Pacific Southwest Research Station USDA Forest Service Riverside California 92607 USA
| | - Linda Geiser
- Washington Office‐Water Wildlife Fish Air and Rare Plants USDA Forest Service Washington D.C. 20250 USA
| | - Laurence Jones
- Environment Centre Wales Centre for Ecology and Hydrology Deiniol Road Bangor LL57 2UW United Kingdom
| | - Tamara F. Blett
- Air Resources Division National Park Service Lakewood Colorado 80225 USA
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48
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Larios L, Hallett LM, Suding KN. Where and how to restore in a changing world: a demographic‐based assessment of resilience. J Appl Ecol 2017. [DOI: 10.1111/1365-2664.12946] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Loralee Larios
- Division of Biological Sciences University of Montana Missoula MT USA
- Department of Botany and Plant Sciences University of California Riverside CA USA
| | - Lauren M. Hallett
- Department of Ecology and Evolutionary Biology Institute of Arctic and Alpine Research University of Colorado Boulder CO USA
- Environmental Studies Program Department of Biology University of Oregon Eugene OR USA
| | - Katharine N. Suding
- Department of Ecology and Evolutionary Biology Institute of Arctic and Alpine Research University of Colorado Boulder CO USA
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49
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Bell MD, Phelan J, Blett TF, Landers D, Nahlik AM, Van Houtven G, Davis C, Clark CM, Hewitt J. A framework to quantify the strength of ecological links between an environmental stressor and final ecosystem services. Ecosphere 2017; 8:e01806. [PMID: 30221018 PMCID: PMC6134850 DOI: 10.1002/ecs2.1806] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Anthropogenic stressors such as climate change, increased fire frequency, and pollution drive shifts in ecosystem function and resilience. Scientists generally rely on biological indicators of these stressors to signal that ecosystem conditions have been altered. However, these biological indicators are not always capable of being directly related to ecosystem components that provide benefits to humans and/or can be used to evaluate the cost-benefit of a change in health of the component (ecosystem services). Therefore, we developed the STEPS (STressor - Ecological Production function - final ecosystem Services) Framework to link changes in a biological indicator of a stressor to final ecosystem services. The STEPS framework produces "chains" of ecological components that explore the breadth of impacts resulting from the change of a stressor. Chains are comprised of the biological indicator, the ecological production function (EPF; which uses ecological components to link the biological indicator to a final ecosystem service), and the user group who directly uses, appreciates, or values the component. The framework uses a qualitative score (High, Medium, Low) to describe the Strength of Science (SOS) for the relationship between each component in the EPF. We tested the STEPS Framework within a workshop setting using the exceedance of critical loads of air pollution as a model stressor and the Final Ecosystem Goods and Services Classification System (FEGS-CS) to describe final ecosystem services. We identified chains for four modes of ecological response to deposition: aquatic acidification, aquatic eutrophication, terrestrial acidification, and terrestrial eutrophication. The workshop participants identified 183 unique EPFs linking a change in a biological indicator to a FEGS; and when accounting for the multiple beneficiaries, we ended with 1104 chains. The SOS scores were effective in identifying chains with the highest confidence ranking as well as those where more research is needed. The STEPS framework could be adapted to any system in which a stressor is modifying a biological component. The results of the analysis can be used by the social science community to apply valuation measures to multiple or selected chains, providing a comprehensive analysis of the effects of anthropogenic stressors on measures of human well-being.
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Affiliation(s)
- Michael D. Bell
- Air Resources Division, National Park Service, Lakewood, Colorado 80225, USA
| | - Jennifer Phelan
- RTI International, 3040 Cornwallis Rd., Research Triangle Park, North Carolina 27709, USA
| | - Tamara F. Blett
- Air Resources Division, National Park Service, Lakewood, Colorado 80225, USA
| | - Dixon Landers
- US Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, Oregon 97333, USA
| | | | - George Van Houtven
- RTI International, 3040 Cornwallis Rd., Research Triangle Park, North Carolina 27709, USA
| | - Christine Davis
- US Environmental Protection Agency, Office of Air and Radiation, Office of Air Quality Planning and Standards, 109 TW Alexander Dr., Research Triangle Park, NC, 27709, USA
| | - Christopher M. Clark
- US Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, 1200 Pennsylvania Ave NW, Washington, DC 20004, USA
| | - Julie Hewitt
- US Environmental Protection Agency, Office of Water, 1200 Pennsylvania Ave. NW, Washington, DC 20004, USA
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50
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Vourlitis GL. Chronic N enrichment and drought alter plant cover and community composition in a Mediterranean-type semi-arid shrubland. Oecologia 2017; 184:267-277. [PMID: 28393274 DOI: 10.1007/s00442-017-3860-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 03/29/2017] [Indexed: 10/19/2022]
Abstract
Anthropogenic nitrogen (N) deposition has caused a decline in native plant species and an increase in exotic plant species in many terrestrial ecosystems; however, vegetation change depends on the rate and/or duration of N input, individual species responses, interactions with other resources, and ecosystem properties such as species richness and canopy cover, soil texture, pH, and/or disturbance regime. Native shrub and exotic forb responses to N enrichment were evaluated over a 13-year field experiment in a mature coastal sage scrub (CSS) shrubland of southern California to test the hypothesis that dry-season N input will cause a decline in native shrubs and an increase in exotic annuals. Nitrogen enrichment caused the dominant native shrubs, Artemisia californica and Salvia mellifera, to respond differently, with A. californica initially increasing with N input but declining thereafter and S. mellifera declining consistently over the 13-year-period. Both species exhibited higher canopy dieback during drought conditions, especially in N plots. Brassica nigra, an exotic annual, invaded N plots significantly more than control plots, but only after 10 years of N addition and a prolonged drought, which increased native shrub canopy dieback. These results indicate a possible synergism between N enrichment and drought on native shrub and exotic forb abundance, which would have important implications for plant diversity in semi-arid shrublands of southwest US that are anticipated to experience an increase in anthropogenic N enrichment and the frequency and duration of drought.
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