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Matlaga D, Lammerant R, Hogan JA, Uriarte M, Rodriguez‐Valle C, Zimmerman JK, Muscarella R. Survival, growth, and functional traits of tropical wet forest tree seedlings across an experimental soil moisture gradient in Puerto Rico. Ecol Evol 2024; 14:e11095. [PMID: 38505185 PMCID: PMC10950389 DOI: 10.1002/ece3.11095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 01/29/2024] [Accepted: 02/19/2024] [Indexed: 03/21/2024] Open
Abstract
Droughts are predicted to become more frequent and intense in many tropical regions, which may cause shifts in plant community composition. Especially in diverse tropical communities, understanding how traits mediate demographic responses to drought can help provide insight into the effects of climate change on these ecosystems. To understand tropical tree responses to reduced soil moisture, we grew seedlings of eight species across an experimental soil moisture gradient at the Luquillo Experimental Forest, Puerto Rico. We quantified survival and growth over an 8-month period and characterized demographic responses in terms of tolerance to low soil moisture-defined as survival and growth rates under low soil moisture conditions-and sensitivity to variation in soil moisture-defined as more pronounced changes in demographic rates across the observed range of soil moisture. We then compared demographic responses with interspecific variation in a suite of 11 (root, stem, and leaf) functional traits, measured on individuals that survived the experiment. Lower soil moisture was associated with reduced survival and growth but traits mediated species-specific responses. Species with relatively conservative traits (e.g., high leaf mass per area), had higher survival at low soil moisture whereas species with more extensive root systems were more sensitive to soil moisture, in that they exhibited more pronounced changes in growth across the experimental soil moisture gradient. Our results suggest that increasing drought will favor species with more conservative traits that confer greater survival in low soil moisture conditions.
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Affiliation(s)
- David Matlaga
- Department of BiologySusquehanna UniversitySelinsgrovePennsylvaniaUSA
| | - Roel Lammerant
- Plant Ecology and EvolutionUppsala UniversityUppsalaSweden
- Tvärminne Zoological StationUniversity of HelsinkiHankoFinland
| | - J. Aaron Hogan
- Department of BiologyUniversity of FloridaGainesvilleFloridaUSA
| | - María Uriarte
- Department of Ecology, Evolution and Environmental BiologyColumbia UniversityNew YorkNew YorkUSA
| | - Celimar Rodriguez‐Valle
- Department of Environmental SciencesUniversity of Puerto Rico‐Rio PiedrasSan JuanPuerto RicoUSA
| | - Jess K. Zimmerman
- Department of Environmental SciencesUniversity of Puerto Rico‐Rio PiedrasSan JuanPuerto RicoUSA
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Ostrowski A, Connolly RM, Brown CJ, Sievers M. Stressor fluctuations alter mechanisms of seagrass community responses relative to static stressors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 900:165865. [PMID: 37516181 DOI: 10.1016/j.scitotenv.2023.165865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/17/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Ecosystems are increasingly affected by multiple anthropogenic stressors that contribute to habitat degradation and loss. Natural ecosystems are highly dynamic, yet multiple stressor experiments often ignore variability in stressor intensity and do not consider how effects could be mediated across trophic levels, with implications for models that underpin stressor management. Here, we investigated the in situ effects of changes in stressor intensity (i.e., fluctuations) and synchronicity (i.e., timing of fluctuations) on a seagrass community, applying the stressors reduced light and physical disturbance to the sediment. We used structural equation models (SEMs) to identify causal effects of dynamic multiple stressors on seagrass shoot density and leaf surface area, and abundance of associated crustaceans. Responses depended on whether stressor intensities fluctuated or remained static. Relative to static stressor exposure at the end of the experiment, shoot density, leaf surface area, and crustacean abundance all declined under in-phase (synchronous; 17, 33, and 30 % less, respectively) and out-of-phase (asynchronous; 11, 28, and 39 % less, respectively) fluctuating treatments. Static treatment increased seagrass leaf surface area and crustacean abundance relative to the control group. We hypothesised that crustacean responses are mediated by changes in seagrass; however, causal analysis found only weak evidence for a mediation effect via leaf surface area. Changes in crustacean abundance, therefore, were primarily a direct response to stressors. Our results suggest that the mechanisms underpinning stress responses change when stressors fluctuate. For instance, increased leaf surface area under static stress could be caused by seagrass acclimating to low light, whereas no response under fluctuating stressors suggests an acclimation response was not triggered. The SEMs also revealed that community responses to the stressors can be independent of one another. Therefore, models based on static experiments may be representing ecological mechanisms not observed in natural ecosystems, and underestimating the impacts of stressors on ecosystems.
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Affiliation(s)
- Andria Ostrowski
- Coastal and Marine Research Centre, Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, QLD 4222, Australia.
| | - Rod M Connolly
- Coastal and Marine Research Centre, Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, QLD 4222, Australia
| | - Christopher J Brown
- Coastal and Marine Research Centre, Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, QLD 4222, Australia
| | - Michael Sievers
- Coastal and Marine Research Centre, Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, QLD 4222, Australia
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Umaña MN, Needham J, Forero-Montaña J, Nytch CJ, Swenson NG, Thompson J, Uriarte M, Zimmerman JK. Demographic trade-offs and functional shifts in a hurricane-impacted tropical forest. ANNALS OF BOTANY 2023; 131:1051-1060. [PMID: 36702550 PMCID: PMC10457028 DOI: 10.1093/aob/mcad004] [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: 07/21/2022] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND AND AIMS Understanding shifts in the demographic and functional composition of forests after major natural disturbances has become increasingly relevant given the accelerating rates of climate change and elevated frequency of natural disturbances. Although plant demographic strategies are often described across a slow-fast continuum, severe and frequent disturbance events influencing demographic processes may alter the demographic trade-offs and the functional composition of forests. We examined demographic trade-offs and the shifts in functional traits in a hurricane-disturbed forest using long-term data from the Luquillo Forest Dynamics Plot (LFPD) in Puerto Rico. METHODS We analysed information on growth, survival, seed rain and seedling recruitment for 30 woody species in the LFDP. In addition, we compiled data on leaf, seed and wood functional traits that capture the main ecological strategies for plants. We used this information to identify the main axes of demographic variation for this forest community and evaluate shifts in community-weighted means for traits from 2000 to 2016. KEY RESULTS The previously identified growth-survival trade-off was not observed. Instead, we identified a fecundity-growth trade-off and an axis representing seedling-to-adult survival. Both axes formed dimensions independent of resprouting ability. Also, changes in tree species composition during the post-hurricane period reflected a directional shift from seedling and tree communities dominated by acquisitive towards conservative leaf economics traits and large seed mass. Wood specific gravity, however, did not show significant directional changes over time. CONCLUSIONS Our study demonstrates that tree demographic strategies coping with frequent storms and hurricane disturbances deviate from strategies typically observed in undisturbed forests, yet the shifts in functional composition still conform to the expected changes from acquisitive to conservative resource-uptake strategies expected over succession. In the face of increased rates of natural and anthropogenic disturbance in tropical regions, our results anticipate shifts in species demographic trade-offs and different functional dimensions.
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Affiliation(s)
- María Natalia Umaña
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48103, USA
| | - Jessica Needham
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Christopher J Nytch
- Department of Environmental Sciences, University of Puerto Rico, Río Piedras, PR 00936, USA
| | - Nathan G Swenson
- Department of Biological Sciences, University of Notre Dame, South Bend, IN 46556, USA
| | - Jill Thompson
- UK Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB, UK
| | - María Uriarte
- Department of Ecology, Evolution & Environmental Biology, Columbia University, New York, NY 10027, USA
| | - Jess K Zimmerman
- Department of Biology, University of Puerto Rico, Río Piedras, PR 00931, USA
- Department of Environmental Sciences, University of Puerto Rico, Río Piedras, PR 00936, USA
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Ramage BS, Johnson DJ, Chan DM. Effects of drought, disturbance, and biotic neighborhood on experimental tree seedling performance. Ecol Evol 2023; 13:e10413. [PMID: 37593754 PMCID: PMC10427772 DOI: 10.1002/ece3.10413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 08/19/2023] Open
Abstract
Forest biodiversity is likely maintained by a complex suite of interacting drivers that vary in importance across both space and time. Contributing factors include disturbance, interannual variation in abiotic variables, and biotic neighborhood effects. To probe ongoing uncertainties and potential interactions, we investigated tree seedling performance in a temperate mid-Atlantic forest ecosystem. We planted seedlings of five native tree species in mapped study plots, half of which were subjected to disturbance, and then monitored seedling survival, height growth, and foliar condition. The final year of data collection encompassed a drought, enabling comparison between intervals varying in water availability. Seedling performance was analyzed as a function of canopy cover and biotic neighborhood (conspecific and heterospecific abundance), including interactions, with separate generalized linear mixed models fit for each interval. All species exhibited: (a) pronounced declines in height growth during the drought year, (b) detrimental effects of adult conspecifics, and (c) beneficial effects of canopy openness. However, despite these consistencies, there was considerable variation across species in terms of the relevant predictors for each response variable in each interval. Our results suggest that drought may strengthen or reveal conspecific inhibition in some instances while weakening it or obscuring it in others, and that some forms of conspecific inhibition may manifest only under particular canopy conditions (although given the inconsistency of our findings, we are not convinced that conspecific inhibition is critical for diversity maintenance in our study system). Overall, our work reveals a complex forest ecosystem that appears simultaneously and interactively governed by biotic neighborhood structure (e.g., conspecific and/or heterospecific abundance), local habitat conditions (e.g., canopy cover), and interannual variability (e.g., drought).
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Affiliation(s)
| | - Daniel J. Johnson
- School of Forest, Fisheries, & Geomatics sciencesUniversity of FloridaGainesvilleFloridaUSA
| | - David M. Chan
- Department of Mathematics and Applied MathematicsVirginia Commonwealth UniversityRichmondVirginiaUSA
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Mensah S, Lokossou CJ, Assogbadjo AE, Kakaï RG. Seasonal variation of environment and conspecific density-dependence effects on early seedling growth of a tropical tree in semi-arid savannahs. Glob Ecol Conserv 2023. [DOI: 10.1016/j.gecco.2023.e02455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
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Gomes AS, Callaway RM, Rabelo BS, Petry GL, Barbosa EM, Borghetti F. Competition for water and rapid exclusion of an island endemic by a pantropical species in a tropical climate. Oecologia 2023; 201:901-914. [PMID: 36973609 DOI: 10.1007/s00442-023-05352-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 03/02/2023] [Indexed: 03/29/2023]
Abstract
Water availability has major effects on community structure and dynamics globally, yet our understanding of competition for water in the tropics is limited. On the tropical Trindade Island, we explored competition for water in the context of the rapid exclusion of an endemic sedge, Cyperus atlanticus (Cyperaceae), by a pantropical, N-fixing shrub, Guilandina bonduc (Fabaceae). Guilandina patches were generally surrounded by rings of bare soil, and dead Cyperus halos commonly surrounded these bare zones. With geo-referenced measurements, we showed that Guilandina patches and bare soil zones rapidly expanded and replaced adjacent Cyperus populations. We found that soil water potentials were much lower in bare soils than soils under Guilandina or Cyperus, and that leaf water potentials of Cyperus plants were lower when co-occurring with Guilandina than when alone. When Guilandina was removed experimentally, Cyperus populations expanded and largely covered the bare soil zones. Our results indicate that when Guilandina establishes, its root systems expand beyond its canopies and these roots pull water from soils beneath Cyperus and kill it, creating bare zone halos, and then Guilandina expands and repeats the process. This scenario indicates rapid competitive exclusion and displacement of an endemic by a common pantropical species, at least in part through competition for water.
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Lebrija-Trejos E, Hernández A, Wright SJ. Effects of moisture and density-dependent interactions on tropical tree diversity. Nature 2023; 615:100-104. [PMID: 36792827 DOI: 10.1038/s41586-023-05717-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 01/08/2023] [Indexed: 02/17/2023]
Abstract
Tropical tree diversity increases with rainfall1,2. Direct physiological effects of moisture availability and indirect effects mediated by biotic interactions are hypothesized to contribute to this pantropical increase in diversity with rainfall2-6. Previous studies have demonstrated direct physiological effects of variation in moisture availability on tree survival and diversity5,7-10, but the indirect effects of variation in moisture availability on diversity mediated by biotic interactions have not been shown11. Here we evaluate the relationships between interannual variation in moisture availability, the strength of density-dependent interactions, and seedling diversity in central Panama. Diversity increased with soil moisture over the first year of life across 20 annual cohorts. These first-year changes in diversity persisted for at least 15 years. Differential survival of moisture-sensitive species did not contribute to the observed changes in diversity. Rather, negative density-dependent interactions among conspecifics were stronger and increased diversity in wetter years. This suggests that moisture availability enhances diversity indirectly through moisture-sensitive, density-dependent conspecific interactions. Pathogens and phytophagous insects mediate interactions among seedlings in tropical forests12-18, and many of these plant enemies are themselves moisture-sensitive19-27. Changes in moisture availability caused by climate change and habitat degradation may alter these interactions and tropical tree diversity.
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Affiliation(s)
- Edwin Lebrija-Trejos
- Department of Biology and Environment, University of Haifa-Oranim, Kiryat Tiv'on, Israel.
| | | | - S Joseph Wright
- Smithsonian Tropical Research Institute, Balboa Ancón, Panama
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He Q, Queenborough SA, Zhang Y, Wang W, Li B, Zhao K, Luo W, Tang H, Lin W, Chu C. Effects of tree sex, maturity, local abiotic, and biotic neighborhoods on the growth of a subtropical dioecious tree species Diospyros morrisiana. AMERICAN JOURNAL OF BOTANY 2023; 110:e16124. [PMID: 36652334 DOI: 10.1002/ajb2.16124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
PREMISE Understanding the drivers of the growth in long-lived woody trees is the key to predicting their responses to and maintaining their populations under global change. However, the role of tree sex and differential investment to reproduction are often not considered in models of individual tree growth, despite many gymnosperm and angiosperm species having separate male and female sexes. Thus, better models of tree growth should include tree sex and life stage along with the abiotic and biotic neighborhoods. METHODS We used a sex-specific molecular marker to determine the sex of 2188 individual trees >1 cm DBH of the dioecious tree species Diospyros morrisiana in a 50-ha subtropical forest plot in China. We used long-term census data from about 300,000 trees, together with 625 soil samples and 2352 hemispherical photographs to characterize the spatially explicit biotic and abiotic neighborhoods. RESULTS We found a male-biased effective sex ratio and a female-biased overall population sex ratio of D. morrisiana. No sex spatial segregation was detected for the overall population, mature, or immature trees. Immature trees grew faster than mature trees and females grew slower than males. Further, conspecific neighbors significantly decreased tree growth, while the abiotic neighborhood showed no significant effect. CONCLUSIONS Our findings suggest that variation in resource allocation patterns within and across individual trees of different sexes and life-history stages should be more widely accounted for in models of tree growth. In addition, our study highlights the importance of sex-specific molecular markers for studying populations of long-lived dioecious tree species.
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Affiliation(s)
- Qing He
- State Key Laboratory of Biocontrol, School of Life Sciences and School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Simon A Queenborough
- Yale School of the Environment, Yale University, New Haven, Connecticut, 06511, USA
| | - Yonghua Zhang
- College of Life and Environmental Sciences, Wenzhou University, Wenzhou, 325000, China
| | - Weitao Wang
- State Key Laboratory of Biocontrol, School of Life Sciences and School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Buhang Li
- State Key Laboratory of Biocontrol, School of Life Sciences and School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Kangning Zhao
- School of Architecture, University of South China, Hengyang, 421001, Hunan, China
| | - Wenqi Luo
- State Key Laboratory of Biocontrol, School of Life Sciences and School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Hui Tang
- State Key Laboratory of Biocontrol, School of Life Sciences and School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Wei Lin
- State Key Laboratory of Biocontrol, School of Life Sciences and School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Chengjin Chu
- State Key Laboratory of Biocontrol, School of Life Sciences and School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
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Kulikowski AJ, Zahawi RA, Werden LK, Zhu K, Holl KD. Restoration interventions mediate tropical tree recruitment dynamics over time. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210077. [PMID: 36373915 PMCID: PMC9661957 DOI: 10.1098/rstb.2021.0077] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/03/2021] [Indexed: 11/16/2022] Open
Abstract
Forest restoration is increasingly heralded as a global strategy to conserve biodiversity and mitigate climate change, yet long-term studies that compare the effects of different restoration strategies on tree recruit demographics are lacking. We measured tree recruit survival and growth annually in three restoration treatments-natural regeneration, applied nucleation and tree plantations-replicated at 13 sites in southern Costa Rica-and evaluated the changes over a decade. Early-successional seedlings had 14% higher survival probability in the applied nucleation than natural regeneration treatments. Early-successional sapling growth rates were initially 227% faster in natural regeneration and 127% faster in applied nucleation than plantation plots but converged across restoration treatments over time. Later-successional seedling and sapling survival were similar across treatments but later-successional sapling growth rates were 39% faster in applied nucleation than in plantation treatments. Results indicate that applied nucleation was equally or more effective in enhancing survival and growth of naturally recruited trees than the more resource-intensive plantation treatment, highlighting its promise as a restoration strategy. Finally, tree recruit dynamics changed quickly over the 10-year period, underscoring the importance of multi-year studies to compare restoration interventions and guide ambitious forest restoration efforts planned for the coming decades. This article is part of the theme issue 'Understanding forest landscape restoration: reinforcing scientific foundations for the UN Decade on Ecosystem Restoration'.
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Affiliation(s)
- Andy J. Kulikowski
- Environmental Studies Department, University of California, Santa Cruz, CA 95064, USA
| | - Rakan A. Zahawi
- Environmental Studies Department, University of California, Santa Cruz, CA 95064, USA
- Lyon Arboretum and School of Life Sciences, University of Hawaii, Honolulu, HI 96822, USA
| | - Leland K. Werden
- Lyon Arboretum and School of Life Sciences, University of Hawaii, Honolulu, HI 96822, USA
| | - Kai Zhu
- Environmental Studies Department, University of California, Santa Cruz, CA 95064, USA
| | - Karen D. Holl
- Environmental Studies Department, University of California, Santa Cruz, CA 95064, USA
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Zhang C, Khan A, Duan CY, Cao Y, Wu DD, Hao GY. Xylem hydraulics strongly influence the niche differentiation of tree species along the slope of a river valley in a water-limited area. PLANT, CELL & ENVIRONMENT 2023; 46:106-118. [PMID: 36253806 DOI: 10.1111/pce.14467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/03/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
Xylem hydraulic characteristics govern plant water transport, affecting both drought resistance and photosynthetic gas exchange. Therefore, they play critical roles in determining the adaptation of different species to environments with various water regimes. Here, we tested the hypothesis that variation in xylem traits associated with a trade-off between hydraulic efficiency and safety against drought-induced embolism contributes to niche differentiation of tree species along a sharp water availability gradient on the slope of a unique river valley located in a semi-humid area. We found that tree species showed clear niche differentiation with decreasing water availability from the bottom towards the top of the valley. Tree species occupying different positions, in terms of vertical distribution distance from the bottom of the valley, showed a strong trade-off between xylem water transport efficiency and safety, as evidenced by variations in xylem structural traits at both the tissue and pit levels. This optimized their xylem hydraulics in their respective water regimes. Thus, the trade-off between hydraulic efficiency and safety contributes to clear niche differentiation and, thereby, to the coexistence of tree species in the valley with heterogeneous water availability.
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Affiliation(s)
- Chi Zhang
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
- Daqinggou Ecological Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Attaullah Khan
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
- Daqinggou Ecological Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Chun-Yang Duan
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
- Daqinggou Ecological Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yu Cao
- Institute of Sand Land Control and Utilization, Liaoning Province, Fuxin, China
| | - De-Dong Wu
- Institute of Sand Land Control and Utilization, Liaoning Province, Fuxin, China
| | - Guang-You Hao
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
- Daqinggou Ecological Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
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11
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A Severe Hurricane Increases Carbon Dioxide and Methane Fluxes and Triples Nitrous Oxide Emissions in a Tropical Forest. Ecosystems 2022. [DOI: 10.1007/s10021-022-00794-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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12
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Lyu Q, Luo Y, Liu S, Zhang Y, Li X, Hou G, Chen G, Zhao K, Fan C, Li X. Forest gaps alter the soil bacterial community of weeping cypress plantations by modulating the understory plant diversity. FRONTIERS IN PLANT SCIENCE 2022; 13:920905. [PMID: 36061809 PMCID: PMC9437579 DOI: 10.3389/fpls.2022.920905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
Weeping cypress is an endemic tree species that is widely planted in China, and the simple stand structure and fragile ecosystem of its plantation are common issues. Exploring the effect of different gap sizes on the soil bacterial community structure of weeping cypress plantations can provide a theoretical basis for the near-natural management of forest plantations. We, therefore, constructed three kinds of forest gaps with different sizes in weeping cypress plantations, namely, small (50-100 m2), medium (100-200 m2), and large gaps (400-667 m2), for identifying the key factors that affect soil bacterial communities following the construction of forest gaps. The results suggested that the herb layer was more sensitive than the shrub layer, while the Simpson, Shannon, and richness indices of the herb layer in plots with gaps were significantly higher than those of designated sampling plots without any gaps (CK). The presence of large gaps significantly increased the understory plant diversity and the Shannon and Simpson indices of the soil bacterial alpha diversity. There were obvious changes in the community composition of soil bacteria following the construction of forest gaps. The dominant bacterial phyla, orders, and functions were similar across the plots with different gap sizes. Of the indicator bacterial species, the abundance of the nitrogen-fixing bacteria, Lysobacter_ yangpyeongensis, and Ensifer_meliloti, was significantly different across plots with different gap sizes and accounted for a large proportion of the bacterial population of plots with medium and large gaps. The understory plant diversity was mostly related to the soil bacterial community than to other soil factors. The results of structural equation modeling indicated that the understory plant diversity was the most important environmental factor in driving the composition and diversity of bacterial communities. The construction of forest gaps significantly improved the understory plant diversity, physicochemical properties of the soil, and bacterial diversity in weeping cypress plantations, and the results of the comprehensive evaluation were in the order: large gaps > small gaps > medium gaps > CK. Our results suggested that large gaps are beneficial for the diversity of above-ground plant communities and underground soil bacterial communities.
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Affiliation(s)
- Qian Lyu
- College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Yan Luo
- College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Size Liu
- Sichuan Academy of Forestry, Chengdu, China
| | - Yan Zhang
- College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Xiangjun Li
- College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Guirong Hou
- College of Forestry, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of National Forestry and Prairie Bureau on Forest Resources Conservation and Ecological Security in the Upper Reaches of Yangtze River, Sichuan Agricultural University, Chengdu, China
- Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Gang Chen
- College of Forestry, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of National Forestry and Prairie Bureau on Forest Resources Conservation and Ecological Security in the Upper Reaches of Yangtze River, Sichuan Agricultural University, Chengdu, China
- Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Kuangji Zhao
- College of Forestry, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of National Forestry and Prairie Bureau on Forest Resources Conservation and Ecological Security in the Upper Reaches of Yangtze River, Sichuan Agricultural University, Chengdu, China
- Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Chuan Fan
- College of Forestry, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of National Forestry and Prairie Bureau on Forest Resources Conservation and Ecological Security in the Upper Reaches of Yangtze River, Sichuan Agricultural University, Chengdu, China
- Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Xianwei Li
- College of Forestry, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of National Forestry and Prairie Bureau on Forest Resources Conservation and Ecological Security in the Upper Reaches of Yangtze River, Sichuan Agricultural University, Chengdu, China
- Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
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Hogan JA, Sharpe JM, Van Beusekom A, Stankavich S, Matta Carmona S, Bithorn JE, Torres‐Díaz J, González G, Zimmerman JK, Shiels AB. Solar radiation and soil moisture drive tropical forest understory responses to experimental and natural hurricanes. Ecosphere 2022. [DOI: 10.1002/ecs2.4150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- J. Aaron Hogan
- Department of Biological Sciences Florida International University Miami Florida USA
- Department of Biology University of Florida Gainesville Florida USA
| | | | - Ashley Van Beusekom
- USDA Forest Service International Institute of Tropical Forestry Río Piedras Puerto Rico USA
| | | | - Samuel Matta Carmona
- Department of Environmental Sciences University of Puerto Rico‐Río Piedras San Juan Puerto Rico USA
| | - John E. Bithorn
- Department of Environmental Sciences University of Puerto Rico‐Río Piedras San Juan Puerto Rico USA
| | - Jamarys Torres‐Díaz
- USDA Forest Service International Institute of Tropical Forestry Río Piedras Puerto Rico USA
- Graduate School of Planning University of Puerto Rico‐Río Piedras San Juan Puerto Rico USA
| | - Grizelle González
- USDA Forest Service International Institute of Tropical Forestry Río Piedras Puerto Rico USA
| | - Jess K. Zimmerman
- Department of Environmental Sciences University of Puerto Rico‐Río Piedras San Juan Puerto Rico USA
| | - Aaron B. Shiels
- USDA APHIS National Wildlife Research Center Fort Collins Colorado USA
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14
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Barber C, Graves SJ, Hall JS, Zuidema PA, Brandt J, Bohlman SA, Asner GP, Bailón M, Caughlin TT. Species-level tree crown maps improve predictions of tree recruit abundance in a tropical landscape. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2585. [PMID: 35333420 DOI: 10.1002/eap.2585] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 10/26/2021] [Accepted: 11/04/2021] [Indexed: 06/14/2023]
Abstract
Predicting forest recovery at landscape scales will aid forest restoration efforts. The first step in successful forest recovery is tree recruitment. Forecasts of tree recruit abundance, derived from the landscape-scale distribution of seed sources (i.e., adult trees), could assist efforts to identify sites with high potential for natural regeneration. However, previous work revealed wide variation in the effect of seed sources on seedling abundance, from positive to no effect. We quantified the relationship between adult tree seed sources and tree recruits and predicted where natural recruitment would occur in a fragmented, tropical, agricultural landscape. We integrated species-specific tree crown maps generated from hyperspectral imagery and property ownership data with field data on the spatial distribution of tree recruits from five species. We then developed hierarchical Bayesian models to predict landscape-scale recruit abundance. Our models revealed that species-specific maps of tree crowns improved recruit abundance predictions. Conspecific crown area had a much stronger impact on recruitment abundance (8.00% increase in recruit abundance when conspecific tree density increases from zero to one tree; 95% credible interval (CI): 0.80% to 11.57%) than heterospecific crown area (0.03% increase with the addition of a single heterospecific tree, 95% CI: -0.60% to 0.68%). Individual property ownership was also an important predictor of recruit abundance: The best performing model had varying effects of conspecific and heterospecific crown area on recruit abundance, depending on individual property ownership. We demonstrate how novel remote sensing approaches and cadastral data can be used to generate high-resolution and landscape-level maps of tree recruit abundance. Spatial models parameterized with field, cadastral, and remote sensing data are poised to assist decision support for forest landscape restoration.
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Affiliation(s)
- Cristina Barber
- Biological Sciences, Boise State University, Boise, Idaho, USA
| | - Sarah J Graves
- Nelson Institute for Environmental Studies, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jefferson S Hall
- Smithsonian Tropical Research Institute, ForestGEO, Panama City, Panama
| | - Pieter A Zuidema
- Forest Ecology and Forest Management group, Wageningen University, Wageningen, The Netherlands
| | - Jodi Brandt
- Human-Environment Systems, Boise State University, Boise, Idaho, USA
| | - Stephanie A Bohlman
- School of Forest Resources and Conservation, University of Florida, Gainesville, Florida, USA
- Smithsonian Tropical Research Institute, Panama City, Panama
| | - Gregory P Asner
- Center for Global Discovery and Conservation Science, Arizona State University, Tempe, Arizona, USA
| | - Mario Bailón
- Smithsonian Tropical Research Institute, Panama City, Panama
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15
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Singh C, van der Ent R, Wang‐Erlandsson L, Fetzer I. Hydroclimatic adaptation critical to the resilience of tropical forests. GLOBAL CHANGE BIOLOGY 2022; 28:2930-2939. [PMID: 35100483 PMCID: PMC9306811 DOI: 10.1111/gcb.16115] [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: 10/26/2021] [Accepted: 01/28/2022] [Indexed: 06/06/2023]
Abstract
Forest and savanna ecosystems naturally exist as alternative stable states. The maximum capacity of these ecosystems to absorb perturbations without transitioning to the other alternative stable state is referred to as 'resilience'. Previous studies have determined the resilience of terrestrial ecosystems to hydroclimatic changes predominantly based on space-for-time substitution. This substitution assumes that the contemporary spatial frequency distribution of ecosystems' tree cover structure holds across time. However, this assumption is problematic since ecosystem adaptation over time is ignored. Here we empirically study tropical forests' stability and hydroclimatic adaptation dynamics by examining remotely sensed tree cover change (ΔTC; aboveground ecosystem structural change) and root zone storage capacity (Sr ; buffer capacity towards water-stress) over the last two decades. We find that ecosystems at high (>75%) and low (<10%) tree cover adapt by instigating considerable subsoil investment, and therefore experience limited ΔTC-signifying stability. In contrast, unstable ecosystems at intermediate (30%-60%) tree cover are unable to exploit the same level of adaptation as stable ecosystems, thus showing considerable ΔTC. Ignoring this adaptive mechanism can underestimate the resilience of the forest ecosystems, which we find is largely underestimated in the case of the Congo rainforests. The results from this study emphasise the importance of the ecosystem's temporal dynamics and adaptation in inferring and assessing the risk of forest-savannah transitions under rapid hydroclimatic change.
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Affiliation(s)
- Chandrakant Singh
- Stockholm Resilience CentreStockholm UniversityStockholmSweden
- Bolin Centre for Climate ResearchStockholm UniversityStockholmSweden
| | - Ruud van der Ent
- Department of Water ManagementFaculty of Civil Engineering and GeosciencesDelft University of TechnologyDelftThe Netherlands
- Department of Physical GeographyFaculty of GeosciencesUtrecht UniversityUtrechtThe Netherlands
| | - Lan Wang‐Erlandsson
- Stockholm Resilience CentreStockholm UniversityStockholmSweden
- Bolin Centre for Climate ResearchStockholm UniversityStockholmSweden
| | - Ingo Fetzer
- Stockholm Resilience CentreStockholm UniversityStockholmSweden
- Bolin Centre for Climate ResearchStockholm UniversityStockholmSweden
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16
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A Study of the Distribution of Forest Density in Inner Mongolia Based on Environmental Factors. FORESTS 2022. [DOI: 10.3390/f13020313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
With the intensification of global climate change, exploring the impact of environmental factors on tree density can provide technical support for sustainable forest management. In this paper, the random forest parameters nTree and mtry were optimized using a particle swarm optimization algorithm. The density, average temperature, soil thickness, forest water consumption, slope, slope direction, slope position, soil type, and diameter at breast height (DBH) of the dominant tree species in Inner Mongolia were fitted using random forest regression with a satisfactory fitting effect (R2 > 0.60). The results show that the average temperature, soil thickness, and forest water consumption were the main factors restricting tree density, and the influence of each factor changed depending on the stage of tree growth. Based on 2018 forest resource data of the Inner Mongolia Autonomous Region, four diameter class models were used to calculate tree density, and Kriging interpolation was used to form a density distribution grid map of the main tree species according to diameter class toward providing a theoretical basis and data support for afforestation and forest management strategies that are justified according to the available environmental resources.
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17
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Effect of Aspect-Slope on the Growth of Conifers in a Harsh Boreal Climate of Northwest Sweden. FORESTS 2022. [DOI: 10.3390/f13020301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tree development is affected by different factors including topographic features. The effect could be even more complex in harsh environments such as in the northwest of Sweden. In this study, we analyzed the effect of aspect-slope on the development up to the age of 34 years of five species: black spruce, lodgepole pine, Norway spruce, Siberian larch and Scots pine. The species were planted in a field experiment on the southwest slope, mountaintop, and northeast slope in a randomized complete block design in the northwest of Sweden (latitude 67°) with 2 m × 2 m spacing. No re-measurement data were available and, as such, retrospective diameters and heights were derived from sample discs and measurement of length to every branch whorl, respectively. Variations in tree survival rate, height and diameter were analyzed using a linear mixed-effect model. The results showed that there were significant (p < 0.05) differences between species in survival rate, diameter and height growth; in some cases, differences were found between contrasting aspect-slope. Black spruce and Siberian larch had the best survival rate under this harsh boreal climate. However, Siberian larch had the best growth and developed well on the mountaintop and northeast slope. Lodgepole pine developed well on the southwest slope. Scots pine also grew well on the southwest slope and mountaintop. Norway spruce had the slowest growth. Based on this study, Siberian larch and lodgepole pine can serve as alternatives to the two traditional conifer species, Norway spruce and Scots pine, used in Sweden. Siberian larch is particularly suitable because it is able to withstand the harshness of the boreal environment.
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18
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Xu Z, Johnson DJ, Zhu K, Lin F, Ye J, Yuan Z, Mao Z, Fang S, Hao Z, Wang X. Interannual climate variability has predominant effects on seedling survival in a temperate forest. Ecology 2022; 103:e3643. [DOI: 10.1002/ecy.3643] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/27/2021] [Accepted: 11/10/2021] [Indexed: 11/10/2022]
Affiliation(s)
- Zhichao Xu
- CAS Key Laboratory of Forest Ecology and Management Institute of Applied Ecology, Chinese Academy of Sciences Shenyang China
- University of Chinese Academy of Sciences Beijing China
| | - Daniel J. Johnson
- School of Forest, Fisheries, and Geomatics Sciences University of Florida Gainesville Florida USA
| | - Kai Zhu
- Department of Environmental Studies University of California Santa Cruz California USA
| | - Fei Lin
- CAS Key Laboratory of Forest Ecology and Management Institute of Applied Ecology, Chinese Academy of Sciences Shenyang China
| | - Ji Ye
- CAS Key Laboratory of Forest Ecology and Management Institute of Applied Ecology, Chinese Academy of Sciences Shenyang China
| | - Zuoqiang Yuan
- CAS Key Laboratory of Forest Ecology and Management Institute of Applied Ecology, Chinese Academy of Sciences Shenyang China
| | - Zikun Mao
- CAS Key Laboratory of Forest Ecology and Management Institute of Applied Ecology, Chinese Academy of Sciences Shenyang China
- University of Chinese Academy of Sciences Beijing China
| | - Shuai Fang
- CAS Key Laboratory of Forest Ecology and Management Institute of Applied Ecology, Chinese Academy of Sciences Shenyang China
| | - Zhanqing Hao
- School of Ecology and Environment Northwestern Polytechnical University Xi'an China
| | - Xugao Wang
- CAS Key Laboratory of Forest Ecology and Management Institute of Applied Ecology, Chinese Academy of Sciences Shenyang China
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19
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Pham VV, Ammer C, Annighöfer P, Heinrichs S. Tree regeneration characteristics in limestone forests of the Cat Ba National Park, Vietnam. BMC Ecol Evol 2022; 22:6. [PMID: 35033001 PMCID: PMC8761296 DOI: 10.1186/s12862-021-01957-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 12/24/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The ability of overstory tree species to regenerate successfully is important for the preservation of tree species diversity and its associated flora and fauna. This study investigated forest regeneration dynamics in the Cat Ba National Park, a biodiversity hotspot in Vietnam. Data was collected from 90 sample plots (500 m2) and 450 sub-sample plots (25 m2) in regional limestone forests. We evaluated the regeneration status of tree species by developing five ratios relating overstory and regeneration richness and diversity. By examining the effect of environmental factors on these ratios, we aimed to identify the main drivers for maintaining tree species diversity or for potential diversity gaps between the regeneration and the overstory layer. Our results can help to increase the understanding of regeneration patterns in tropical forests of Southeast Asia and to develop successful conservation strategies. RESULTS We found 97 tree species in the regeneration layer compared to 136 species in the overstory layer. The average regeneration density was 3764 ± 1601 per ha. Around 70% of the overstory tree species generated offspring. According to the International Union for Conservation of Nature's Red List, only 36% of threatened tree species were found in the regeneration layer. A principal component analysis provided evidence that the regeneration of tree species was slightly negatively correlated to terrain factors (percentage of rock surface, slope) and soil properties (cation exchange capacity, pH, humus content, soil moisture, soil depth). Contrary to our expectations, traces of human impact and the prevailing light conditions (total site factor, gap fraction, openness, indirect site factor, direct site factor) had no influence on regeneration density and composition, probably due to the small gradient in light availability. CONCLUSION We conclude that the tree species richness in Cat Ba National Park appears to be declining at present. We suggest similar investigations in other biodiversity hotspots to learn whether the observed trend is a global phenomenon. In any case, a conservation strategy for the threatened tree species in the Cat Ba National Park needs to be developed if tree species diversity is to be maintained.
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Affiliation(s)
- Van Vien Pham
- Forestry Faculty, Northeast College of Forest and Agriculture, 207657, Quangninh, Vietnam. .,Silviculture and Forest Ecology of the Temperate Zones, Georg-August-University Göttingen, Büsgenweg 1, 37077, Göttingen, Germany.
| | - Christian Ammer
- Silviculture and Forest Ecology of the Temperate Zones, Georg-August-University Göttingen, Büsgenweg 1, 37077, Göttingen, Germany
| | - Peter Annighöfer
- Forest and Agroforest Systems, Technical University of Munich, Hans-Carl-v.-Carlowitz-Platz 2, 85354, Freising, Germany
| | - Steffi Heinrichs
- Silviculture and Forest Ecology of the Temperate Zones, Georg-August-University Göttingen, Büsgenweg 1, 37077, Göttingen, Germany
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20
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Scott ER, Uriarte M, Bruna EM. Delayed effects of climate on vital rates lead to demographic divergence in Amazonian forest fragments. GLOBAL CHANGE BIOLOGY 2022; 28:463-479. [PMID: 34697872 DOI: 10.1111/gcb.15900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/08/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Deforestation often results in landscapes where remaining forest habitat is highly fragmented, with remnants of different sizes embedded in an often highly contrasting matrix. Local extinction of species from individual fragments is common, but the demographic mechanisms underlying these extinctions are poorly understood. It is often hypothesized that altered environmental conditions in fragments drive declines in reproduction, recruitment, or survivorship. The Amazon basin, in addition to experiencing continuing fragmentation, is experiencing climate change-related increases in the frequency and intensity of droughts and unusually wet periods. Whether plant populations in tropical forest fragments are particularly susceptible to extremes in precipitation remains unclear. Most studies of plants in fragments are relatively short (1-6 years), focus on a single life-history stage, and often do not compare to populations in continuous forest. Even fewer studies consider delayed effects of climate on demographic vital rates despite the importance of delayed effects in studies that consider them. Using a decade of demographic and climate data from an experimentally fragmented landscape in the Central Amazon, we assess the effects of climate on populations of an understory herb (Heliconia acuminata, Heliconiaceae). We used distributed lag nonlinear models to understand the delayed effects of climate (measured as standardized precipitation evapotranspiration index, SPEI) on survival, growth, and flowering. We detected delayed effects of climate up to 36 months. Extremes in SPEI in the previous year reduced survival, drought in the wet season 8-11 months prior to the February census increased growth, and drought two dry seasons prior increased flowering probability. Effects of extremes in precipitation on survival and growth were more pronounced in forest fragments compared to continuous forest. The complex delayed effects of climate and habitat fragmentation in our study point to the importance of long-term demography experiments in understanding the effects of anthropogenic change on plant populations.
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Affiliation(s)
- Eric R Scott
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, Florida, USA
| | - María Uriarte
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, New York, USA
| | - Emilio M Bruna
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, Florida, USA
- Center for Latin American Studies, University of Florida, Gainesville, Florida, USA
- Biological Dynamics of Forest Fragments Project, INPA-PDBFF, Manaus, Amazonas, Brazil
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21
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Fang C, Chen H, Castillo-Díaz D, Wen B, Cao KF, Goodale UM. Regeneration and Endogenous Phytohormone Responses to High-Temperature Stress Drive Recruitment Success in Hemiepiphytic Fig Species. FRONTIERS IN PLANT SCIENCE 2021; 12:754207. [PMID: 34912356 PMCID: PMC8666629 DOI: 10.3389/fpls.2021.754207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/25/2021] [Indexed: 06/14/2023]
Abstract
Exposure to high-temperature stress (HTS) during early regeneration in plants can profoundly shape seed germination, seedling growth, and development, thereby providing stress resilience. In this study, we assessed how the timing of HTS, which was implemented as 8 h in 40°C, could affect the early regeneration stages and phytohormone concentration of four hemiepiphytic (Hs) and four non-hemiepiphytic (NHs) Ficus species. Their seed germination, seedling emergence, and seedling survival probabilities and the concentrations of three endogenous phytohormones, abscisic acid (ABA), indole-3-acetic acid (IAA), and salicylic acid (SA) were assessed after HTS imposed during imbibition, germination, and emergence. In both groups, seeds were more sensitive to HTS in the early regeneration process; stress experienced during imbibition affected emergence and survival, and stress experienced during germination affected subsequent emergence. There was no effect from HTS when received after emergence. Survival was highest in hemiepiphytes regardless of the HTS treatment. The phytohormones showed growth form- and regeneration stage-specific responses to HTS. Due to the HTS treatment, both SA and ABA levels decreased in non-hemiepiphytes during imbibition and germination; during germination, IAA increased in hemiepiphytes but was reduced in non-hemiepiphytes. Due to the HTS treatment experienced during emergence ABA and IAA concentrations were greater for hemiepiphytes but an opposite effect was seen in the two growth forms for the SA concentration. Our study showed that the two growth forms have different strategies for regulating their growth and development in the early regeneration stages in order to respond to HTS. The ability to respond to HTS is an ecologically important functional trait that allows plant species to appropriately time their seed germination and seedling development. Flexibility in modulating species regeneration in response to HTS in these subtropical and tropical Ficus species could provide greater community resilience under climate change.
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Affiliation(s)
- Chuangwei Fang
- Guangxi Key Laboratory of Forestry Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Huayang Chen
- Guangxi Key Laboratory of Forestry Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Nanning, China
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- Seed Conservation Specialist Group, Species Survival Commission, International Union for Conservation of Nature, Gland, Switzerland
| | - Diana Castillo-Díaz
- Guangxi Key Laboratory of Forestry Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Nanning, China
- Seed Conservation Specialist Group, Species Survival Commission, International Union for Conservation of Nature, Gland, Switzerland
| | - Bin Wen
- Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Beijing, China
| | - Kun-Fang Cao
- Guangxi Key Laboratory of Forestry Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Nanning, China
| | - Uromi Manage Goodale
- Guangxi Key Laboratory of Forestry Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Nanning, China
- Seed Conservation Specialist Group, Species Survival Commission, International Union for Conservation of Nature, Gland, Switzerland
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22
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Quebbeman A, Davis R, Thompson J, Zimmerman JK, Uriarte M. Percolation threshold analyses can detect community assembly processes in simulated and natural tree communities. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andrew Quebbeman
- Department of Ecology Evolution & Environmental Biology Columbia University New York NY USA
| | - Richard Davis
- Department of Statistics Columbia University New York NY USA
| | | | - Jess K. Zimmerman
- Department of Environmental Sciences University of Puerto Rico San Juan PR USA
| | - María Uriarte
- Department of Ecology Evolution & Environmental Biology Columbia University New York NY USA
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23
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Rammer W, Braziunas KH, Hansen WD, Ratajczak Z, Westerling AL, Turner MG, Seidl R. Widespread regeneration failure in forests of Greater Yellowstone under scenarios of future climate and fire. GLOBAL CHANGE BIOLOGY 2021; 27:4339-4351. [PMID: 34213047 DOI: 10.1111/gcb.15726] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 05/18/2021] [Accepted: 05/22/2021] [Indexed: 06/13/2023]
Abstract
Changing climate and disturbance regimes are increasingly challenging the resilience of forest ecosystems around the globe. A powerful indicator for the loss of resilience is regeneration failure, that is, the inability of the prevailing tree species to regenerate after disturbance. Regeneration failure can result from the interplay among disturbance changes (e.g., larger and more frequent fires), altered climate conditions (e.g., increased drought), and functional traits (e.g., method of seed dispersal). This complexity makes projections of regeneration failure challenging. Here we applied a novel simulation approach assimilating data-driven fire projections with vegetation responses from process modeling by means of deep neural networks. We (i) quantified the future probability of regeneration failure; (ii) identified spatial hotspots of regeneration failure; and (iii) assessed how current forest types differ in their ability to regenerate under future climate and fire. We focused on the Greater Yellowstone Ecosystem (2.9 × 106 ha of forest) in the Rocky Mountains of the USA, which has experienced large wildfires in the past and is expected to undergo drastic changes in climate and fire in the future. We simulated four climate scenarios until 2100 at a fine spatial grain (100 m). Both wildfire activity and unstocked forest area increased substantially throughout the 21st century in all simulated scenarios. By 2100, between 28% and 59% of the forested area failed to regenerate, indicating considerable loss of resilience. Areas disproportionally at risk occurred where fires are not constrained by topography and in valleys aligned with predominant winds. High-elevation forest types not adapted to fire (i.e., Picea engelmannii-Abies lasiocarpa as well as non-serotinous Pinus contorta var. latifolia forests) were especially vulnerable to regeneration failure. We conclude that changing climate and fire could exceed the resilience of forests in a substantial portion of Greater Yellowstone, with profound implications for carbon, biodiversity, and recreation.
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Affiliation(s)
- Werner Rammer
- Ecosystem Dynamics and Forest Management Group, Technical University of Munich, Freising, Germany
| | - Kristin H Braziunas
- Department of Integrative Biology, University of Wisconsin, Madison, WI, USA
| | - Winslow D Hansen
- Earth Institute, Columbia University, New York City, NY, USA
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
| | - Zak Ratajczak
- Department of Integrative Biology, University of Wisconsin, Madison, WI, USA
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | | | - Monica G Turner
- Department of Integrative Biology, University of Wisconsin, Madison, WI, USA
| | - Rupert Seidl
- Ecosystem Dynamics and Forest Management Group, Technical University of Munich, Freising, Germany
- Berchtesgaden National Park, Berchtesgaden, Germany
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24
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Matsuo T, Martínez‐Ramos M, Bongers F, van der Sande MT, Poorter L. Forest structure drives changes in light heterogeneity during tropical secondary forest succession. THE JOURNAL OF ECOLOGY 2021; 109:2871-2884. [PMID: 34588706 PMCID: PMC8453511 DOI: 10.1111/1365-2745.13680] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 04/16/2021] [Indexed: 06/07/2023]
Abstract
Light is a key resource for tree performance and hence, tree species partition spatial and temporal gradients in light availability. Although light distribution drives tree performance and species replacement during secondary forest succession, we yet lack understanding how light distribution changes with tropical forest development.This study aims to evaluate how changes in forest structure lead to changes in vertical and horizontal light heterogeneity during tropical forest succession.We described successional patterns in light using a chronosequence approach in which we compared 14 Mexican secondary forest stands that differ in age (8-32 years) since agricultural abandonment. For each stand, we measured vertical light profiles in 16 grid cells, and structural parameters (diameter at breast height, height and crown dimensions) for each tree.During succession, we found a rapid increase in stand size (basal area, crown area and length) and stand differentiation (i.e. a gradual leaf distribution along the forest profile), which leads to fast changes in light conditions and more light heterogeneity. The inflection points of the vertical light gradient (i.e. the absolute height at which 50% relative light intensity is attained) rapidly moved towards higher heights in the first 20 years, indicating that larger amounts of light are intercepted by canopy trees. Light attenuation rate (i.e. the rate of light extinction) decreased during succession due to slower accumulation of the crown area with height. Understorey light intensity and heterogeneity slightly decreased during succession because of an increase in crown size and a decrease in lateral gap frequency. Understorey relative light intensity was 1.56% at 32 years after abandonment.Synthesis. During succession, light conditions changed linearly, which should lead to a continuous and constant replacement of species. Especially in later successional stages, stronger vertical light gradients can limit the regeneration of light-demanding pioneer species and increase the proportion of shade-tolerant late-successional species under the canopy. These changes in light conditions were largely driven by the successional changes in forest structure, as basal area strongly determined the height where most light is absorbed, whereas crown area, and to a lesser extent crown length, determined light distribution.
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Affiliation(s)
- Tomonari Matsuo
- Forest Ecology and Forest Management GroupWageningen UniversityWageningenThe Netherlands
| | - Miguel Martínez‐Ramos
- Instituto de Investigaciones en Ecosistemas y SustentabilidadUniversidad Nacional Autónoma de MéxicoMoreliaMichoacánMéxico
| | - Frans Bongers
- Forest Ecology and Forest Management GroupWageningen UniversityWageningenThe Netherlands
| | - Masha T. van der Sande
- Forest Ecology and Forest Management GroupWageningen UniversityWageningenThe Netherlands
| | - Lourens Poorter
- Forest Ecology and Forest Management GroupWageningen UniversityWageningenThe Netherlands
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25
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Quebbeman AW, Menge DNL, Zimmerman J, Uriarte M. Topography and Tree Species Improve Estimates of Spatial Variation in Soil Greenhouse Gas Fluxes in a Subtropical Forest. Ecosystems 2021. [DOI: 10.1007/s10021-021-00677-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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26
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Worthy SJ, Rubio VE, Staiger K, Ngouajio B, Yang J, Swenson NG. Site‐specific impacts of a major hurricane on alpha and beta diversity in tropical forest seedling communities. Ecosphere 2021. [DOI: 10.1002/ecs2.3651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Samantha J. Worthy
- Department of Biology University of Maryland College Park Maryland 20742 USA
| | - Vanessa E. Rubio
- Department of Biological Sciences University of Notre Dame South Bend Indiana 46556 USA
| | - Kirstin Staiger
- Department of Biology University of Maryland College Park Maryland 20742 USA
| | - Boris Ngouajio
- Department of Biology University of Maryland College Park Maryland 20742 USA
| | - Jie Yang
- CAS Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Mengla 666303 China
- Center of Plant Ecology Core Botanical Gardens Chinese Academy of Sciences Mengla 666303 China
| | - Nathan G. Swenson
- Department of Biological Sciences University of Notre Dame South Bend Indiana 46556 USA
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Thomas E, Jansen M, Chiriboga-Arroyo F, Wadt LHO, Corvera-Gomringer R, Atkinson RJ, Bonser SP, Velasquez-Ramirez MG, Ladd B. Habitat Quality Differentiation and Consequences for Ecosystem Service Provision of an Amazonian Hyperdominant Tree Species. FRONTIERS IN PLANT SCIENCE 2021; 12:621064. [PMID: 33868327 PMCID: PMC8044455 DOI: 10.3389/fpls.2021.621064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 03/03/2021] [Indexed: 06/12/2023]
Abstract
Ecosystem services of Amazonian forests are disproportionally produced by a limited set of hyperdominant tree species. Yet the spatial variation in the delivery of ecosystem services by individual hyperdominant species across their distribution ranges and corresponding environmental gradients is poorly understood. Here, we use the concept of habitat quality to unravel the effect of environmental gradients on seed production and aboveground biomass (AGB) of the Brazil nut, one of Amazonia's largest and most long-lived hyperdominants. We find that a range of climate and soil gradients create trade-offs between density and fitness of Brazil nut trees. Density responses to environmental gradients were in line with predictions under the Janzen-Connell and Herms-Mattson hypotheses, whereas tree fitness responses were in line with resource requirements of trees over their life cycle. These trade-offs resulted in divergent responses in area-based seed production and AGB. While seed production and AGB of individual trees (i.e., fitness) responded similarly to most environmental gradients, they showed opposite tendencies to tree density for almost half of the gradients. However, for gradients creating opposite fitness-density responses, area-based seed production was invariable, while trends in area-based AGB tended to mirror the response of tree density. We conclude that while the relation between environmental gradients and tree density is generally indicative of the response of AGB accumulation in a given area of forest, this is not necessarily the case for fruit production.
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Affiliation(s)
| | - Merel Jansen
- Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, Ecosystem Management, ETH Zürich, Zurich, Switzerland
- Center for International Forestry Research -CIFOR, Lima, Peru
| | - Fidel Chiriboga-Arroyo
- Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, Ecosystem Management, ETH Zürich, Zurich, Switzerland
| | | | | | | | - Stephen P. Bonser
- School of Biological, Earth and Environmental Science, Ecology & Evolution Research Centre, University of New South Wales, Sydney, NSW, Australia
| | | | - Brenton Ladd
- Escuela de Agroforestería, Universidad Científica del Sur, Lima, Peru
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Factors affecting survival of seedling of Afzelia africana, a threatened tropical timber species in West Africa. Trop Ecol 2021. [DOI: 10.1007/s42965-021-00160-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Ribeiro KFO, Martins VF, Wiegand T, Santos FAM. Habitat filtering drives the local distribution of congeneric species in a Brazilian white-sand flooded tropical forest. Ecol Evol 2021; 11:1797-1813. [PMID: 33614004 PMCID: PMC7882942 DOI: 10.1002/ece3.7169] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 01/29/2023] Open
Abstract
The investigation of ecological processes that maintain species coexistence is revealing in naturally disturbed environments such as the white-sand tropical forest, which is subject to periodic flooding that might pose strong habitat filtering to tree species. Congeneric species are a good model to investigate the relative importance of ecological processes that maintain high species diversity because they tend to exploit the same limiting resources and/or have similar tolerance limits to the same environmental conditions due to their close phylogenetic relationship. We aim to find evidence for the action and relative importance of different processes hypothesized to maintain species coexistence in a white-sand flooded forest in Brazil, taking advantage of data on the detailed spatial structure of populations of congeneric species. Individuals of three Myrcia species were tagged, mapped, and measured for diameter at soil height in a 1-ha plot. We also sampled seven environmental variables in the plot. We employed several spatial point process models to investigate the possible action of habitat filtering, interspecific competition, and dispersal limitation. Habitat filtering was the most important process driving the local distribution of the three Myrcia species, as they showed associations, albeit of different strength, to environmental variables related to flooding. We did not detect spatial patterns, such as spatial segregation and smaller size of nearby neighbors, that would be consistent with interspecific competition among the three congeneric species and other co-occurring species. Even though congeners were spatially independent, they responded to differences in the environment. Last, dispersal limitation only led to spatial associations of different size classes for one of the species. Given that white-sand flooded forests are highly threatened in Brazil, the preservation of their different habitats is of utmost importance to the maintenance of high species richness, as flooding drives the distribution of species in the community.
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Affiliation(s)
- Kelly F. O. Ribeiro
- Programa de Pós‐Graduação em EcologiaInstitute of BiologyUniversity of Campinas ‐ UNICAMPCampinasBrazil
| | - Valéria F. Martins
- Department of Natural Sciences, Maths and EducationFederal University of São Carlos ‐ UFSCarArarasBrazil
- Department of Plant BiologyInstitute of BiologyUniversity of Campinas ‐ UNICAMPCampinasBrazil
| | - Thorsten Wiegand
- Department of Ecological ModellingHelmholtz Centre for Environmental Research – UFZLeipzigGermany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐LeipzigLeipzigGermany
| | - Flavio A. M. Santos
- Department of Plant BiologyInstitute of BiologyUniversity of Campinas ‐ UNICAMPCampinasBrazil
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Umaña MN, Arellano G, Swenson NG, Zambrano J. Tree seedling trait optimization and growth in response to local-scale soil and light variability. Ecology 2021; 102:e03252. [PMID: 33219522 DOI: 10.1002/ecy.3252] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/31/2020] [Accepted: 09/14/2020] [Indexed: 11/09/2022]
Abstract
At local scales, it has been suggested that high levels of resources lead to increased tree growth via trait optimization (highly peaked trait distribution). However, this contrasts with (1) theories that suggest that trait optimization and high growth occur in the most common resource level and (2) empirical evidence showing that high trait optimization can be also found at low resource levels. This raises the question of how are traits and growth optimized in highly diverse plant communities. Here, we propose a series of hypotheses about how traits and growth are expected to be maximized under different resource levels (low, the most common, and high) in tree seedling communities from a subtropical forest in Puerto Rico, USA. We studied the variation in the distribution of biomass allocation and leaf traits and seedlings growth rate along four resource gradients: light availability (canopy openness) and soil K, Mg, and N content. Our analyses consisted of comparing trait kurtosis (a measurement of trait optimization), community trait means, and relative growth rates at three resource levels (low, common, and high). Trait optimization varied across the three resource levels depending on the type of resource and trait, with leaf traits being optimized under high N and in the most common K and Mg conditions, but not at any of the light levels. Also, seedling growth increased at high-light conditions and high N and K but was not related to trait kurtosis. Our results indicate that local-scale variability of soil fertility and understory light conditions result in shifts in species ecological strategies that increase growth despite a weak trait optimization, suggesting the existence of alternative phenotypes that achieve similar high performance. Uncovering the links between abiotic factors, functional trait diversity and performance is necessary to better predict tree responses to future changes in abiotic conditions.
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Affiliation(s)
- María Natalia Umaña
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Gabriel Arellano
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Nathan G Swenson
- Department of Biology, University of Maryland, College Park, Maryland, 20742, USA
| | - Jenny Zambrano
- The School of Biological Sciences, Washington State University, Pullman, Washington, 99164, USA
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31
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Fu H, Yuan G, Özkan K, Johansson LS, Søndergaard M, Lauridsen TL, Jeppesen E. Seasonal and long-term trends in the spatial heterogeneity of lake phytoplankton communities over two decades of restoration and climate change. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 748:141106. [PMID: 32814284 DOI: 10.1016/j.scitotenv.2020.141106] [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: 04/26/2020] [Revised: 06/24/2020] [Accepted: 07/18/2020] [Indexed: 06/11/2023]
Abstract
World-wide, reducing the external nutrient loading to lakes has been the primary priority of lake management in the restoration of eutrophic lakes over the past decades, and as expected this has resulted in an increase in the local environmental heterogeneity, and thus biotic heterogeneity, within lakes. However, little is known about how the regional spatial heterogeneity of lake biotic communities changes with restoration across a landscape. Using a long-term monitoring dataset from 20 Danish lakes, we elucidated the seasonal and long-term trends in the spatial heterogeneity of climate, local abiotic variables and phytoplankton communities over two decades of restoration and climate change at landscape level. We found significant seasonality in the spatial heterogeneity of most climatic and local drivers as well as in the total beta diversity (Sørensen coefficient) and its turnover components (Simpson coefficient) of phytoplankton communities among the lakes. The seasonality tended to be less marked in deep than in shallow lakes. We found significant spatial homogenisation of most local drivers (except for alkalinity) and phytoplankton communities after two decades of restoration and that turnover dominated the temporal responses of the total beta diversity of phytoplankton communities. Path analyses showed that the homogenisation of phytoplankton communities was mainly due to a decrease in spatial heterogeneity of total phosphorus and Schmidt stability in shallow lakes and to a decrease in spatial total phosphorus and total nitrogen heterogeneity in deep lakes. However, albeit weakly, the spatial heterogeneity of the phytoplankton communities was affected indirectly by climatic warming in both shallow and deep lakes and directly by wind speed in shallow lakes. We conclude that restoration of eutrophic lakes may lead to an increase in the local heterogeneity of phytoplankton communities at lake scale and an increase in homogeneity at landscape scale.
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Affiliation(s)
- Hui Fu
- Ecology Department, College of Resources & Environments, Hunan Provincial Key Laboratory of Rural Ecosystem Health in Dongting Lake Area, Hunan Agricultural University, Changsha 410128, PR China.
| | - Guixiang Yuan
- Ecology Department, College of Resources & Environments, Hunan Provincial Key Laboratory of Rural Ecosystem Health in Dongting Lake Area, Hunan Agricultural University, Changsha 410128, PR China
| | - Korhan Özkan
- Institute of Marine Sciences, Middle East Technical University, Mersin, Turkey
| | | | - Martin Søndergaard
- Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark; Sino-Danish Centre for Education and Research (SDC), University of Chinese Academy of Sciences, Beijing, China
| | - Torben L Lauridsen
- Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark; Sino-Danish Centre for Education and Research (SDC), University of Chinese Academy of Sciences, Beijing, China
| | - Erik Jeppesen
- Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark; Sino-Danish Centre for Education and Research (SDC), University of Chinese Academy of Sciences, Beijing, China; Limnology Laboratory, Department of Biological Sciences, Centre for Ecosystem Research and Implementation, Middle East Technical University, Ankara, Turkey
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32
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Mensah S, Noulèkoun F, Dimobe K, Atanasso J, Salako VK, Assogbadjo A, Glèlè Kakaï R. Revisiting biotic and abiotic drivers of seedling establishment, natural enemies and survival in a tropical tree species in a West Africa semi-arid biosphere reserve. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 276:111268. [PMID: 32889500 DOI: 10.1016/j.jenvman.2020.111268] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 07/09/2020] [Accepted: 08/18/2020] [Indexed: 06/11/2023]
Abstract
Biotic and abiotic drivers of seedling establishment and survival are fundamental not only for elucidating processes occurring at plant early life stages, but also for assisting species natural regeneration. Keystone, multipurpose and economically important tree species such as Afzelia africana Sm. are reportedly facing recruitment constraints, yet little is known about how abiotic and biotic factors shape the species seedling dynamics. Here, we monitored the species seedlings over one year across three seasons in West Africa savannahs to determine how conspecific and heterospecific biotic neighborhood and habitat heterogeneity correlate with initial seedling density, leaves' fungal infection and herbivory and how all these factors combined, influence the species seedling survival. Seedling densities increased with increasing conspecific adult densities, and were highest in tree savannahs and on sandy-silt soils. Leaves' fungal infection and herbivory were also positively associated with conspecific adult density, but were more abundantly observed in tree savannahs than in shrub savannahs. Seedling survival was constrained on higher slope, and negatively affected by conspecific adult density, especially in shrub savannahs. There was a strong evidence for negative density-dependence effects of conspecific adults on seedling survival, which operated through negative effects of herbivory and fungal infection. Habitat heterogeneity was also an important driver, which modulated biotic factors' effects on seedling survival: tree savannahs promote positive conspecific density-dependence of seedling fungal infection and herbivory more than shrub savannahs. Nonetheless, seedlings were more sensitive to natural enemies in shrub savannahs, suggesting increased negative conspecific density-dependence effects on seedling survival in less dense vegetation, possibly as a result of enhanced specialization of predators and pathogens on a limited set of species. The study brings important insights into the mechanisms that drive the establishment and survival of the species seedling, which should be considered in the design of management activities aiming at the conservation of this endangered species.
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Affiliation(s)
- Sylvanus Mensah
- Laboratoire de Biomathématiques et d'Estimations Forestières, Université d'Abomey Calavi, 04 BP 1525, Cotonou, Benin.
| | - Florent Noulèkoun
- Department of Environmental Science and Ecological Engineering, Korea University, 145 Anamro, Seongbukgu, Seoul, 02841, South Korea
| | - Kangbéni Dimobe
- Laboratory of Plant Biology and Ecology, University Joseph Ki-Zerbo, 03 B.P. 7021, Ouagadougou 03, Burkina Faso; Institut des Sciences de l'Environnement et du Développement Rural, Université de Dédougou, BP 176, Dédougou, Burkina Faso
| | - Justin Atanasso
- Laboratoire de Biomathématiques et d'Estimations Forestières, Université d'Abomey Calavi, 04 BP 1525, Cotonou, Benin
| | - Valère K Salako
- Laboratoire de Biomathématiques et d'Estimations Forestières, Université d'Abomey Calavi, 04 BP 1525, Cotonou, Benin; Evolution Biologique et Ecologie, Université Libre de Bruxelles, Faculté des Sciences, CP160/12, Av. F. D. Roosevelt 50, BE-1050, Brussels, Belgium
| | - Achille Assogbadjo
- Laboratoire d'Ecologie Appliquée, Université d'Abomey Calavi, 03 BP 526, Cotonou, Benin
| | - Romain Glèlè Kakaï
- Laboratoire de Biomathématiques et d'Estimations Forestières, Université d'Abomey Calavi, 04 BP 1525, Cotonou, Benin
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33
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Ibáñez I, Rodríguez A. Understanding neighborhood effects to increase restoration success of woody plant communities. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2020; 30:e02098. [PMID: 32083369 DOI: 10.1002/eap.2098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 12/02/2019] [Accepted: 01/06/2020] [Indexed: 06/10/2023]
Abstract
Revegetation is the most common procedure in the restoration of disturbed areas; this practice usually aims at reconstructing plant communities that can last without further management. A low-cost strategy to assist these efforts is the application of ecological knowledge in the design of the restoration. Promoting ecological processes that enhance the functioning of the restored community could result in higher restoration success. Among these processes, plant-plant interactions, e.g., facilitation and competition, can play an important role, both facilitating and impeding the development of a self-sustaining plant community. Although these processes have been well-studied in nature, we rarely have sufficient knowledge about the whole plant community. To develop that knowledge, we leverage on a restoration experiment that took place after a mine toxic spill, where ~15,000 woody plants from 13 species were planted and geolocated. Species were planted in three mixtures mimicking natural communities found along soil moisture gradients (xerophyte, intermediate, and hydrophyte). Plantings also varied in density. Approximately 2,600 plants were monitored for damage status, survival, and growth, for 4 yr. We analyzed growth performance of six targeted species as a function of their damage status, planted mixture, and density. Growth was also assessed on the basis of neighboring plants, accounting for the species identity and distance to the focal plant. Results show that survival among planted species was relatively high and was mostly unaffected by mixture or density of the plantings. Only very damaged plants in one species experienced a decrease in survival with increasing density. Neighborhood effects on growth show positive, neutral, and negative interactions among the tested species; these also varied depending on the type of growth performance considered (height, crown area, diameter). The species-specific results ranged from positive to negative, varying between pair of species and growth performance metric. Results gathered from our neighborhood analyses on plant growth provide valuable information for the design of planting schemes that could enhance the performance of the target species. The methods developed can be applied to other systems and species. Given the potential impacts that facilitation and competition may have during revegetation, these interactions could be considered in restoration operations.
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Affiliation(s)
- Inés Ibáñez
- School for Environment and Sustainability, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Alejandro Rodríguez
- Department of Conservation Biology, Estación Biológica de Doñana - CSIC, Sevilla, Spain
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34
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Bachelot B, Alonso-Rodríguez AM, Aldrich-Wolfe L, Cavaleri MA, Reed SC, Wood TE. Altered climate leads to positive density-dependent feedbacks in a tropical wet forest. GLOBAL CHANGE BIOLOGY 2020; 26:3417-3428. [PMID: 32196863 DOI: 10.1111/gcb.15087] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/02/2020] [Indexed: 05/12/2023]
Abstract
Climate change is predicted to result in warmer and drier Neotropical forests relative to current conditions. Negative density-dependent feedbacks, mediated by natural enemies, are key to maintaining the high diversity of tree species found in the tropics, yet we have little understanding of how projected changes in climate are likely to affect these critical controls. Over 3 years, we evaluated the effects of a natural drought and in situ experimental warming on density-dependent feedbacks on seedling demography in a wet tropical forest in Puerto Rico. In the +4°C warming treatment, we found that seedling survival increased with increasing density of the same species (conspecific). These positive density-dependent feedbacks were not associated with a decrease in aboveground natural enemy pressure. If positive density-dependent feedbacks are not transient, the diversity of tropical wet forests, which may rely on negative density dependence to drive diversity, could decline in a future warmer, drier world.
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Affiliation(s)
| | - Aura M Alonso-Rodríguez
- USDA Forest Service International Institute of Tropical Forestry, Jardín Botánico Sur, Río Piedras, Puerto Rico
| | - Laura Aldrich-Wolfe
- Department of Biological Sciences, North Dakota State University, Fargo, ND, USA
| | - Molly A Cavaleri
- School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI, USA
| | - Sasha C Reed
- Southwest Biological Science Center, US Geological Survey, Moab, UT, USA
| | - Tana E Wood
- USDA Forest Service International Institute of Tropical Forestry, Jardín Botánico Sur, Río Piedras, Puerto Rico
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35
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Denney DA, Jameel MI, Bemmels JB, Rochford ME, Anderson JT. Small spaces, big impacts: contributions of micro-environmental variation to population persistence under climate change. AOB PLANTS 2020; 12:plaa005. [PMID: 32211145 PMCID: PMC7082537 DOI: 10.1093/aobpla/plaa005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 02/06/2020] [Indexed: 05/05/2023]
Abstract
Individuals within natural populations can experience very different abiotic and biotic conditions across small spatial scales owing to microtopography and other micro-environmental gradients. Ecological and evolutionary studies often ignore the effects of micro-environment on plant population and community dynamics. Here, we explore the extent to which fine-grained variation in abiotic and biotic conditions contributes to within-population variation in trait expression and genetic diversity in natural plant populations. Furthermore, we consider whether benign microhabitats could buffer local populations of some plant species from abiotic stresses imposed by rapid anthropogenic climate change. If microrefugia sustain local populations and communities in the short term, other eco-evolutionary processes, such as gene flow and adaptation, could enhance population stability in the longer term. We caution, however, that local populations may still decline in size as they contract into rare microhabitats and microrefugia. We encourage future research that explicitly examines the role of the micro-environment in maintaining genetic variation within local populations, favouring the evolution of phenotypic plasticity at local scales and enhancing population persistence under global change.
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Affiliation(s)
- Derek A Denney
- Department of Plant Biology, University of Georgia, Athens, GA, USA
| | - M Inam Jameel
- Department of Genetics, University of Georgia, Athens, GA, USA
| | - Jordan B Bemmels
- Department of Genetics, University of Georgia, Athens, GA, USA
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Mia E Rochford
- Department of Plant Biology, University of Georgia, Athens, GA, USA
| | - Jill T Anderson
- Department of Genetics, University of Georgia, Athens, GA, USA
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36
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Fortunel C, Stahl C, Heuret P, Nicolini E, Baraloto C. Disentangling the effects of environment and ontogeny on tree functional dimensions for congeneric species in tropical forests. THE NEW PHYTOLOGIST 2020; 226:385-395. [PMID: 31872884 DOI: 10.1111/nph.16393] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 12/06/2019] [Indexed: 06/10/2023]
Abstract
Soil water and nutrient availability are key drivers of tree species distribution and forest ecosystem functioning, with strong species differences in water and nutrient use. Despite growing evidence for intraspecific trait differences, it remains unclear under which circumstances the effects of environmental gradients trump those of ontogeny and taxonomy on important functional dimensions related to resource use, particularly in tropical forests. Here, we explore how physiological, chemical, and morphological traits related to resource use vary between life stages in four species within the genus Micropholis that is widespread in lowland Amazonia. Specifically, we evaluate how environment, developmental stage, and taxonomy contribute to single-trait variation and multidimensional functional strategies. We find that environment, developmental stage, and taxonomy differentially contribute to functional dimensions. Habitats and seasons shape physiological and chemical traits related to water and nutrient use, whereas developmental stage and taxonomic identity impact morphological traits -especially those related to the leaf economics spectrum. Our findings suggest that combining environment, ontogeny, and taxonomy allows for a better understanding of important functional dimensions in tropical trees and highlights the need for integrating tree physiological and chemical traits with classically used morphological traits to improve predictions of tropical forests' responses to environmental change.
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Affiliation(s)
- Claire Fortunel
- AMAP (Botanique et Modélisation de l'Architecture des Plantes et des Végétations), Université de Montpellier, CIRAD, CNRS, INRA, IRD, Montpellier, France
| | - Clément Stahl
- UMR EcoFoG (Ecology of Guiana Forests), INRA, AgroParisTech, CIRAD, CNRS, Université de Guyane, Université des Antilles, 97379, Kourou, France
| | - Patrick Heuret
- AMAP (Botanique et Modélisation de l'Architecture des Plantes et des Végétations), Université de Montpellier, CIRAD, CNRS, INRA, IRD, Montpellier, France
| | - Eric Nicolini
- AMAP (Botanique et Modélisation de l'Architecture des Plantes et des Végétations), Université de Montpellier, CIRAD, CNRS, INRA, IRD, Montpellier, France
| | - Christopher Baraloto
- UMR EcoFoG (Ecology of Guiana Forests), INRA, AgroParisTech, CIRAD, CNRS, Université de Guyane, Université des Antilles, 97379, Kourou, France
- Department of Biological Sciences, Florida International University, Miami, FL, 33133, USA
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37
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Umaña MN, Arellano G, Forero‐Montaña J, Nytch CJ, Swenson NG, Thompson J, Uriarte M, Zimmerman JK. Large‐ and small‐seeded species have contrasting functional neighborhoods in a subtropical forest. Ecosphere 2020. [DOI: 10.1002/ecs2.3016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- María Natalia Umaña
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109 USA
| | - Gabriel Arellano
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109 USA
- ForestGEO Smithsonian Tropical Research Institute Washington D.C. 20013 USA
| | | | - Christopher J. Nytch
- Department of Biology University of Puerto Rico Río Piedras Puerto Rico 00931 USA
| | - Nathan G. Swenson
- Department of Biology University of Maryland College Park Maryland 20742 USA
| | - Jill Thompson
- Centre for Ecology & Hydrology Bush Estate Penicuik Midlothian EH26 0QB UK
| | - María Uriarte
- Department of Ecology, Evolution& Environmental Biology Columbia University New York New York 10027 USA
| | - Jess K. Zimmerman
- Department of Biology University of Puerto Rico Río Piedras Puerto Rico 00931 USA
- Department of Environmental Science University of Puerto Rico Río Piedras Puerto Rico 00936 USA
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38
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Kupers SJ, Wirth C, Engelbrecht BMJ, Hernández A, Condit R, Wright SJ, Rüger N. Performance of tropical forest seedlings under shade and drought: an interspecific trade-off in demographic responses. Sci Rep 2019; 9:18784. [PMID: 31827158 PMCID: PMC6906455 DOI: 10.1038/s41598-019-55256-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 11/23/2019] [Indexed: 11/09/2022] Open
Abstract
Seedlings in moist tropical forests must cope with deep shade and seasonal drought. However, the interspecific relationship between seedling performance in shade and drought remains unsettled. We quantified spatiotemporal variation in shade and drought in the seasonal moist tropical forest on Barro Colorado Island (BCI), Panama, and estimated responses of naturally regenerating seedlings as the slope of the relationship between performance and shade or drought intensity. Our performance metrics were relative height growth and first-year survival. We investigated the relationship between shade and drought responses for up to 63 species. There was an interspecific trade-off in species responses to shade versus species responses to dry season intensity; species that performed worse in the shade did not suffer during severe dry seasons and vice versa. This trade-off emerged in part from the absence of species that performed particularly well or poorly in both drought and shade. If drought stress in tropical forests increases with climate change and as solar radiation is higher during droughts, the trade-off may reinforce a shift towards species that resist drought but perform poorly in the shade by releasing them from deep shade.
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Affiliation(s)
- Stefan J Kupers
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany.
| | - Christian Wirth
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany
- Systematic Botany and Functional Biodiversity, Institute of Biology, Leipzig University, Johannisallee 21-23, 04103, Leipzig, Germany
- Max-Planck-Institute for Biogeochemistry, Hans-Knöll Str. 10, 07745, Jena, Germany
| | - Bettina M J Engelbrecht
- Department of Plant Ecology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, 95447, Bayreuth, Germany
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama
| | - Andrés Hernández
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama
| | - Richard Condit
- Field Museum of Natural History, 1400 S Lake Shore Dr., Chicago, IL, 60605, USA
- Morton Arboretum, Lisle, IL, 60532-1293, USA
| | - S Joseph Wright
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama
| | - Nadja Rüger
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Panama
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39
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Chen L, Wang Y, Mi X, Liu X, Ren H, Chen J, Ma K, Kraft NJB. Neighborhood effects explain increasing asynchronous seedling survival in a subtropical forest. Ecology 2019; 100:e02821. [PMID: 31310665 DOI: 10.1002/ecy.2821] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 05/07/2019] [Accepted: 06/13/2019] [Indexed: 01/30/2023]
Abstract
Biotic interactions play a critical role in mediating community responses to temporal environmental variation, but the importance of these effects relative to the direct effects of environmental change remains poorly understood, particularly in diverse forest communities. Here we combine a neighborhood modeling approach with insights from coexistence theory to assess the effects of temporal variation in species interactions and environmental conditions (e.g., precipitation, temperature, and understory light availability) on seedling survival over nine census years in a subtropical forest. We find significant temporal shifts in the magnitude of neighborhood effects on both community-wide and species-level seedling survival (statistically significant random effects of neighborhood × year and neighborhood × species × year interactions). These results are consistent with the idea that environmental change will play a fundamental role on forest regeneration dynamics by altering biotic interactions at the neighborhood scale. Moreover, differences among species in response to neighbors over time contribute to a pattern of temporal decoupling of seedling survival between species, which can help to promote diversity in certain contexts. In separate analyses of multiple regression on distance matrices (MRM), altered interactions with neighbors are much stronger predictors of asynchronous seedling survival among species than the pure effects of climate and plant functional traits, explaining twice as much variation (43.9% vs. 22.2%). In sum, these results reveal that divergent species responses to interannual environmental variability detected are driven primarily by indirect effects mediated by changing biotic environments. This highlights the importance of including indirect effects from local biotic (neighborhood) interactions in forecasts of forest community responses to global change.
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Affiliation(s)
- Lei Chen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, 90095, USA
| | - Yunquan Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.,Key Laboratory for Biodiversity Science and Ecological Engineering of Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Xiangcheng Mi
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Xiaojuan Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Haibao Ren
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Jianhua Chen
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China
| | - Keping Ma
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Nathan J B Kraft
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, 90095, USA
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40
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Dry season soil water potential maps of a 50 hectare tropical forest plot on Barro Colorado Island, Panama. Sci Data 2019; 6:63. [PMID: 31101819 PMCID: PMC6525163 DOI: 10.1038/s41597-019-0072-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 04/12/2019] [Indexed: 11/23/2022] Open
Abstract
Fine scale spatial variation in soil moisture influences plant performance, species distributions and diversity. However, detailed information on local soil moisture variation is scarce, particularly in species-rich tropical forests. We measured soil water potential and soil water content in the 50-ha Forest Dynamics Plot on Barro Colorado Island (BCI), Panama, one of the best-studied tropical forests in the world. We present maps of soil water potential for several dry season stages during a regular year and during an El Niño drought. Additionally, we provide code that allows users to create maps for specific dates. The maps can be combined with other freely available datasets such as long-term vegetation censuses (ranging from seeds to adult trees), data on other resources (e.g. light and nutrients) and remote sensing data (e.g. LiDAR and imaging spectroscopy). Users can study questions in various disciplines such as population and community ecology, plant physiology and hydrology under current and future climate conditions. Design Type(s) | modeling and simulation objective • data collection and processing objective | Measurement Type(s) | wetness of soil | Technology Type(s) | computational modeling technique | Factor Type(s) | season | Sample Characteristic(s) | Barro Colorado Island • primary forest |
Machine-accessible metadata file describing the reported data (ISA-Tab format)
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41
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Liu Y, He F. Incorporating the disease triangle framework for testing the effect of soil‐borne pathogens on tree species diversity. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13345] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Yu Liu
- ECNU‐Alberta Joint Lab for Biodiversity Study, Tiantong Forest Ecosystem National Observation and Research Station, School of Ecology and Environmental Sciences East China Normal University Shanghai China
- Shanghai Institute of Pollution Control and Ecological Security Shanghai China
| | - Fangliang He
- ECNU‐Alberta Joint Lab for Biodiversity Study, Tiantong Forest Ecosystem National Observation and Research Station, School of Ecology and Environmental Sciences East China Normal University Shanghai China
- Department of Renewable Resources University of Alberta Edmonton Alberta Canada
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42
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Schwartz NB, Budsock AM, Uriarte M. Fragmentation, forest structure, and topography modulate impacts of drought in a tropical forest landscape. Ecology 2019; 100:e02677. [PMID: 30825323 DOI: 10.1002/ecy.2677] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 01/23/2019] [Accepted: 02/04/2019] [Indexed: 02/02/2023]
Abstract
Climate models predict increases in drought conditions in many parts of the tropics. Yet the response of tropical forests to drought remains highly uncertain, especially with regards to the factors that generate spatial heterogeneity in drought response across landscapes. In this study, we used Landsat imagery to assess the impacts of a severe drought in 2015 across an ~80,000-ha landscape in Puerto Rico. Specifically, we asked whether drought effects varied systematically with topography and with forest age, height, and fragmentation. We quantified drought impacts using anomalies of two vegetation indices, the enhanced vegetation index (EVI) and normalized difference water index (NDWI), and fit random forest models of these metrics including slope, aspect, forest age, canopy height, and two indices of fragmentation as predictors. Drought effects were more severe on drier topographic positions, that is, steeper slopes and southwest-facing aspects, and in second-growth forests. Shorter and more fragmented forests were also more strongly affected by drought. We also assessed which factors were associated with stronger recovery from drought. Factors associated with more negative drought anomalies were also associated with more positive postdrought anomalies, suggesting that increased light availability as a result of drought led to high rates of recovery in forests more severely affected by drought. In general, recovery from drought was rapid across the landscape, with postdrought anomalies at or above average across the study area. This suggests that forests in Puerto Rico might be resilient to a single-year drought, though vulnerability to drought varies depending on forest characteristics and landscape position.
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Affiliation(s)
- Naomi B Schwartz
- Department of Geography, University of British Columbia, 1984 West Mall, Vancouver, British Columbia, V6T 1Z2, Canada.,Department of Ecology, Evolution, and Behavior, University of Minnesota, 1479 Gortner Avenue, St. Paul, Minnesota, 55108, USA.,Department of Ecology Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, New York, 10027, USA
| | - Andrew M Budsock
- Department of Ecology Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, New York, 10027, USA
| | - María Uriarte
- Department of Ecology Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, New York, 10027, USA
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43
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Ramseyer CA, Miller PW, Mote TL. Future precipitation variability during the early rainfall season in the El Yunque National Forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 661:326-336. [PMID: 30677680 DOI: 10.1016/j.scitotenv.2019.01.167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 01/11/2019] [Accepted: 01/13/2019] [Indexed: 06/09/2023]
Abstract
El Yunque National Forest, situated in the Luquillo Mountains of northeast Puerto Rico, is home to a wide range of climate-sensitive ecosystems and forest types. In particular, these ecosystems are highly sensitive to changes in the hydroclimate, even on short time scales. Current global climate models (GCMs) predict coarse-scale reductions in precipitation across the Caribbean prompting the need to investigate future fine-scale hydroclimate variability in the Luquillo Mountains. This research downscales coarse-resolution GCM RCP8.5 predictions from the IPCC CMIP5 project to the local scale to better assess future rainfall variability during the most critical period of the annual hydroclimate cycle, the early rainfall season (ERS). An artificial neural network (ANN) is developed using five field variables (1000-, 850-, 700-, and 500-hPa specific humidity and 1000-700-hPa bulk wind shear) and four derived precipitation forecasting parameters from the ERA-Interim reanalysis. During the historical period (1985-2016), the ANN predicts a binary dry (<5 mm) versus wet (≥5 mm) day outcome with 92% percent accuracy. When the historical inputs are replaced with bias-corrected data from four CMIP5 GCMs, the downscaled ensemble mean indicates a 7.2% increase in ERS dry-day frequency by mid-century (2041-2060), yielding an ERS dry-day percentage of 70% by mid-century. The results presented here show that the decrease in precipitation and wet-days is, at least in part, due to an increase in 1000-700 hPa bulk wind shear and a less favorable thermodynamic environment driven by increased mid-tropospheric warming and a stronger trade wind inversion. By regressing ERS total precipitation against dry-day frequency (R2 = 0.95), the predicted mid-century dry-day proportion corresponds to a ~200-mm decrease in seasonal precipitation. In contrast, the ensemble predicts a dry-day frequency recovery back towards the historical climatological mean by end-century (2081-2100).
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Affiliation(s)
- Craig A Ramseyer
- Department of Geography and Geosciences, Salisbury University, Salisbury, MD, United States of America.
| | - Paul W Miller
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA
| | - Thomas L Mote
- Department of Geography, University of Georgia, Athens, Georgia
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44
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Umaña MN, Forero‐Montaña J, Nytch CJ, Thompson J, Uriarte M, Zimmerman J, Swenson NG. Dry conditions and disturbance promote liana seedling survival and abundance. Ecology 2019; 100:e02556. [DOI: 10.1002/ecy.2556] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 09/07/2018] [Accepted: 10/11/2018] [Indexed: 01/08/2023]
Affiliation(s)
- María Natalia Umaña
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109 USA
- Department of Biology University of Maryland College Park Maryland 20742 USA
| | | | - Christopher J. Nytch
- Department of Biology University of Puerto Rico Río Piedras Puerto Rico 00931 USA
| | - Jill Thompson
- Centre for Ecology & Hydrology Bush Estate, Penicuik Midlothian EH26 0QB United Kingdom
| | - María Uriarte
- Department of Ecology, Evolution & Environmental Biology Columbia University New York New York 10027 USA
| | - Jess Zimmerman
- Department of Biology University of Puerto Rico Río Piedras Puerto Rico 00931 USA
- Department of Environmental Sciences University of Puerto Rico Río Piedras Puerto Rico 00936 USA
| | - Nathan G. Swenson
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109 USA
- Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Kunming China
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45
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Changes in Phylogenetic Community Structure of the Seedling Layer Following Hurricane Disturbance in a Human-Impacted Tropical Forest. FORESTS 2018. [DOI: 10.3390/f9090556] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Disturbance plays a key role in shaping forest composition and diversity. We used a community phylogeny and long-term forest dynamics data to investigate biotic and abiotic factors shaping tropical forest regeneration following both human and natural disturbance. Specifically, we examined shifts in seedling phylogenetic and functional (i.e., seed mass) community structure over a decade following a major hurricane in a human-impacted forest in Puerto Rico. Phylogenetic relatedness of the seedling community decreased in the first five years post-hurricane and then increased, largely driven by changes in the abundance of a common palm species. Functional structure (based on seed mass) became increasingly clustered through time, due to canopy closure causing small-seeded, light-demanding species to decline in abundance. Seedling neighbor density and phylogenetic relatedness negatively affected seedling survival, which likely acted to reduce phylogenetic relatedness within seedling plots. Across the study site, areas impacted in the past by high-intensity land use had lower or similar phylogenetic relatedness of seedling communities than low-intensity past land use areas, reflecting interactive effects of human and natural disturbance. Our study demonstrates how phylogenetic and functional information offer insights into the role of biotic and abiotic factors structuring forest recovery following disturbance.
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46
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Seed Dispersal, Microsites or Competition—What Drives Gap Regeneration in an Old-Growth Forest? An Application of Spatial Point Process Modelling. FORESTS 2018. [DOI: 10.3390/f9050230] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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