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Wall CB, Swift SOI, D’Antonio CM, Gebauer G, Hynson NA. Isoscapes of remnant and restored Hawaiian montane forests reveal differences in biological nitrogen fixation and carbon inputs. PeerJ 2023; 11:e15468. [PMID: 37304880 PMCID: PMC10252893 DOI: 10.7717/peerj.15468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 05/05/2023] [Indexed: 06/13/2023] Open
Abstract
Deforestation and subsequent land-use conversion has altered ecosystems and led to negative effects on biodiversity. To ameliorate these effects, nitrogen-fixing (N2-fixing) trees are frequently used in the reforestation of degraded landscapes, especially in the tropics; however, their influence on ecosystem properties such as nitrogen (N) availability and carbon (C) stocks are understudied. Here, we use a 30-y old reforestation site of outplanted native N2-fixing trees (Acacia koa) dominated by exotic grass understory, and a neighboring remnant forest dominated by A. koa canopy trees and native understory, to assess whether restoration is leading to similar N and C biogeochemical landscapes and soil and plant properties as a target remnant forest ecosystem. We measured nutrient contents and isotope values (δ15N, δ13C) in soils, A. koa, and non-N2-fixing understory plants (Rubus spp.) and generated δ15N and δ13C isoscapes of the two forests to test for (1) different levels of biological nitrogen fixation (BNF) and its contribution to non-N2-fixing understory plants, and (2) the influence of historic land conversion and more recent afforestation on plant and soil δ13C. In the plantation, A. koa densities were higher and foliar δ15N values for A. koa and Rubus spp. were lower than in the remnant forest. Foliar and soil isoscapes also showed a more homogeneous distribution of low δ15N values in the plantation and greater influence of A. koa on neighboring plants and soil, suggesting greater BNF. Foliar δ13C also indicated higher water use efficiency (WUEi) in the plantation, indicative of differences in plant-water relations or soil water status between the two forest types. Plantation soil δ13C was higher than the remnant forest, consistent with greater contributions of exotic C4-pasture grasses to soil C pools, possibly due to facilitation of non-native grasses by the dense A. koa canopy. These findings are consequential for forest restoration, as they contribute to the mounting evidence that outplanting N2-fixing trees produces different biogeochemical landscapes than those observed in reference ecosystems, thereby influencing plant-soil interactions which can influence restoration outcomes.
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Affiliation(s)
- Christopher B. Wall
- University of California, San Diego, San Diego, CA, United States
- University of Hawaii at Manoa, Honolulu, HI, United States
| | | | - Carla M. D’Antonio
- University of California, Santa Barbara, Santa Barbara, CA, United States
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2
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Reade H, Tripp JA, Frémondeau D, Sayle KL, Higham TFG, Street M, Stevens RE. Nitrogen palaeo-isoscapes: Changing spatial gradients of faunal δ15N in late Pleistocene and early Holocene Europe. PLoS One 2023; 18:e0268607. [PMID: 36745587 PMCID: PMC9901814 DOI: 10.1371/journal.pone.0268607] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 01/22/2023] [Indexed: 02/07/2023] Open
Abstract
Nitrogen isotope ratio analysis (δ15N) of animal tissue is widely used in archaeology and palaeoecology to investigate diet and ecological niche. Data interpretations require an understanding of nitrogen isotope compositions at the base of the food web (baseline δ15N). Significant variation in animal δ15N has been recognised at various spatiotemporal scales and related to changes both in baseline δ15N, linked to environmental and climatic influence on the terrestrial nitrogen cycle, and animal ecology. Isoscapes (models of isotope spatial variation) have proved a useful tool for investigating spatial variability in biogeochemical cycles in present-day marine and terrestrial ecosystems, but so far, their application to palaeo-data has been more limited. Here, we present time-sliced nitrogen isoscapes for late Pleistocene and early Holocene Europe (c. 50,000 to 10,000 years BP) using herbivore collagen δ15N data. This period covers the Last Glacial-Interglacial Transition, during which significant variation in the terrestrial nitrogen cycle occurred. We use generalized linear mixed modelling approaches for interpolation and test models which both include and exclude climate covariate data. Our results show clear changes in spatial gradients of δ15N through time. Prediction of the lowest faunal δ15N values in northern latitudes after, rather than during, the Last Glacial Maximum is consistent with the Late Glacial Nitrogen Excursion (LGNE). We find that including climatic covariate data does not significantly improve model performance. These findings have implications for investigating the drivers of the LGNE, which has been linked to increased landscape moisture and permafrost thaw, and for understanding changing isotopic baselines, which are fundamental for studies investigating diets, niche partitioning, and migration of higher trophic level animals.
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Affiliation(s)
- Hazel Reade
- UCL Institute of Archaeology, University College London, London, United Kingdom
- * E-mail:
| | - Jennifer A. Tripp
- UCL Institute of Archaeology, University College London, London, United Kingdom
| | - Delphine Frémondeau
- UCL Institute of Archaeology, University College London, London, United Kingdom
| | - Kerry L. Sayle
- Scottish Universities Environmental Research Centre, Glasgow, United Kingdom
| | - Thomas F. G. Higham
- Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford, United Kingdom
| | - Martin Street
- Römisch-Germanisches Zentralmuseum, Forschungsinstitut für Archäologie Kompetenzbereich Pleistozäne und Frühholozäne Archäologie, Neuwied, Germany
| | - Rhiannon E. Stevens
- UCL Institute of Archaeology, University College London, London, United Kingdom
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3
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Bindewald A, Brundu G, Schueler S, Starfinger U, Bauhus J, Lapin K. Site-specific risk assessment enables trade-off analysis of non-native tree species in European forests. Ecol Evol 2021; 11:18089-18110. [PMID: 35003660 PMCID: PMC8717284 DOI: 10.1002/ece3.8407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/27/2021] [Accepted: 11/12/2021] [Indexed: 12/23/2022] Open
Abstract
Non-native tree species (NNT) are used in European forestry for many purposes including their growth performance, valuable timber, and resistance to drought and pest or pathogen damage. Yet, cultivating NNT may pose risks to biodiversity, ecosystem functioning, and the provisioning of ecosystem services, and several NNT have been classified as invasive in Europe. Typically, such classifications are based on risk assessments, which do not adequately consider site-specific variations in impacts of the NNT or the extent of affected areas. Here, we present a new methodological framework that facilitates both mitigating risks associated with NNT and taking advantage of their ecosystem services. The framework is based on a stratified assessment of risks posed by NNT which distinguishes between different sites and considers effectiveness of available management strategies to control negative effects. The method can be applied to NNT that already occur in a given area or those NNT that may establish in future. The framework consists of eight steps and is partly based on existing knowledge. If adequate site-specific knowledge on NNT does not yet exist, new evidence on the risks should be obtained, for example, by collecting and analyzing monitoring data or modeling the potential distribution of NNT. However, limitations remain in the application of this method, and we propose several policy and management recommendations which are required to improve the responsible use of NNT.
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Affiliation(s)
- Anja Bindewald
- Department of Forest ConservationForest Research Institute of Baden‐Württemberg (FVA)FreiburgGermany
- Chair of SilvicultureUniversity of FreiburgFreiburgGermany
| | - Giuseppe Brundu
- Department of Agricultural SciencesUniversity of SassariSassariItaly
| | | | - Uwe Starfinger
- Julius Kühn‐Institut (JKI)Federal Research Centre for Cultivated PlantsBraunschweigGermany
| | - Jürgen Bauhus
- Chair of SilvicultureUniversity of FreiburgFreiburgGermany
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4
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Pellegrini E, Boscutti F, Alberti G, Casolo V, Contin M, De Nobili M. Stand age, degree of encroachment and soil characteristics modulate changes of C and N cycles in dry grassland soils invaded by the N 2-fixing shrub Amorpha fruticosa. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 792:148295. [PMID: 34147804 DOI: 10.1016/j.scitotenv.2021.148295] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 06/12/2023]
Abstract
The N2-fixing shrub Amorpha fruticosa L. is rapidly spreading in the dry riparian natural grasslands of Europe, altering ecosystem functions and depleting plant diversity. Alteration of the N cycle represents the key factor involved in invasions by N2-fixing plants with cascading effects on plant species richness. We hypothesized that A. fruticosa encroachment strongly impacts not only the N but also the C cycle and that the magnitude of such alterations may be modulated by soil characteristics. To test these hypotheses, we selected four river floodplains in North East of Italy and compared natural uninvaded grasslands with half invaded and completely invaded sites, based on A. fruticosa stand characteristic and relevant leaf traits and on soil properties related to soil texture and to C and N cycles. Soil organic matter mineralisation, ammonification and nitrification rates were determined. Soil nitrification increased remarkably with plant invasion while ammonification was significantly higher only in half invaded sites. Soil organic matter mineralisation, microbial biomass C sustained per soil organic C unit and nitrification positively correlated with stand age, regardless to the stage of the encroachment. Mineralisation and nitrification increased with soil organic C and total N in uninvaded and completely invaded sites, but decreased in half invaded sites. At the half invasion stage, trends in nitrification and CO2 mineralisation were transitionally reverted and remediation may be facilitated by less pronounced changes in soil properties compared to completely invaded sites. Direct effects of plant invasion are modulated by the action of soil characteristics such as soil organic C and clay contents, with soils rich in organic C showing larger nitrification and mineralisation rates.
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Affiliation(s)
- E Pellegrini
- Department of Biology, University of Copenhagen, Universitetsparken 4, 3rd floor, 2100, København Ø, Denmark; Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze 206, 33100, Udine, Italy.
| | - F Boscutti
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze 206, 33100, Udine, Italy
| | - G Alberti
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze 206, 33100, Udine, Italy
| | - V Casolo
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze 206, 33100, Udine, Italy
| | - M Contin
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze 206, 33100, Udine, Italy
| | - M De Nobili
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze 206, 33100, Udine, Italy
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5
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McCue MD, Javal M, Clusella‐Trullas S, Le Roux JJ, Jackson MC, Ellis AG, Richardson DM, Valentine AJ, Terblanche JS. Using stable isotope analysis to answer fundamental questions in invasion ecology: Progress and prospects. Methods Ecol Evol 2019. [DOI: 10.1111/2041-210x.13327] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Marshall D. McCue
- Sable Systems International Las Vegas NV USA
- Department of Conservation Ecology and Entomology Centre for Invasion Biology Stellenbosch University Stellenbosch South Africa
| | - Marion Javal
- Department of Conservation Ecology and Entomology Centre for Invasion Biology Stellenbosch University Stellenbosch South Africa
| | - Susana Clusella‐Trullas
- Centre for Invasion Biology Department of Botany and Zoology Stellenbosch University Stellenbosch South Africa
| | - Johannes J. Le Roux
- Centre for Invasion Biology Department of Botany and Zoology Stellenbosch University Stellenbosch South Africa
- Department of Biological Sciences Macquarie University NSW Australia
| | - Michelle C. Jackson
- Centre for Invasion Biology Department of Botany and Zoology Stellenbosch University Stellenbosch South Africa
- Department of Life Sciences Imperial College London Ascot UK
- Department of Zoology Oxford University Oxford UK
| | - Allan G. Ellis
- Department of Botany and Zoology Stellenbosch University Stellenbosch South Africa
| | - David M. Richardson
- Centre for Invasion Biology Department of Botany and Zoology Stellenbosch University Stellenbosch South Africa
| | - Alex J. Valentine
- Department of Botany and Zoology Stellenbosch University Stellenbosch South Africa
| | - John S. Terblanche
- Department of Conservation Ecology and Entomology Centre for Invasion Biology Stellenbosch University Stellenbosch South Africa
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6
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Gilbert JA, Corbin JD. Biological soil crusts inhibit seed germination in a temperate pine barren ecosystem. PLoS One 2019; 14:e0212466. [PMID: 30785942 PMCID: PMC6382267 DOI: 10.1371/journal.pone.0212466] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/01/2019] [Indexed: 11/18/2022] Open
Abstract
Biological soil crusts (BSCs) are known to affect plants’ germination and seedling establishment in arid ecosystems, but their ecological role in more mesic climates is not so well-known. We tested the effects of moss-crusted versus uncrusted soils on seed germination dynamics in a temperate pine barren ecosystem. We conducted a 35-day laboratory assay of seed germination on moss-crusted soils versus uncrusted soils from the Albany (NY) Pine Bush Preserve. We compared total seed germination and the number of days to 50% of total germination of two herbaceous perennial forb species in each soil type. Three and five times more seeds germinated on uncrusted soil than on crusted soil for bush clover (Lespedeza capitata) and wild lupine (Lupinus perennis), respectively. Seeds of both species also germinated approximately 10 days earlier on uncrusted soil than on crusted soil. This study, and others in similar habitats, show that BSCs in mesic climates can influence germination and other early life-history stages of plants. We hope that further study of the interactions between BSCs and vascular plants in mesic climates will contribute to our understanding of the ecology of BSCs outside the arid and semiarid climates where they are more extensively studied.
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Affiliation(s)
- Jessica A. Gilbert
- Department of Biological Sciences, Union College, Schenectady, New York, United States of America
| | - Jeffrey D. Corbin
- Department of Biological Sciences, Union College, Schenectady, New York, United States of America
- * E-mail:
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7
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McLoughlin PD, Lysak K, Debeffe L, Perry T, Hobson KA. Density-dependent resource selection by a terrestrial herbivore in response to sea-to-land nutrient transfer by seals. Ecology 2018; 97:1929-1937. [PMID: 27859192 DOI: 10.1002/ecy.1451] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/12/2016] [Accepted: 03/14/2016] [Indexed: 11/07/2022]
Abstract
Sea-to-land nutrient transfers can connect marine food webs to those on land, creating a dependence on marine webs by opportunistic species. We show how nitrogen, imported by gray seals, Halichoerus grypus, and traced through stable isotope (δ15 N) measurements in marram grass, Ammophila breviligulata, significantly alters foraging behavior of a free-roaming megaherbivore (feral horses, Equus ferus caballus) on Sable Island, Canada. Values of δ15 N correlated with protein content of marram and strongly related to pupping-seal densities, and positively influenced selective foraging by horses. The latter was density dependent, consistent with optimal foraging theory. We present the first demonstration of how sea-to-land nutrient transfers can affect the behavioral process of resource selection (resource use relative to availability) of terrestrial consumers. We hypothesize that persistence of horses on Sable Island is being facilitated by N subsidies. Our results have relevance to advancing theory on trophic dynamics in island biogeography and metaecosystem ecology.
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Affiliation(s)
- Philip D McLoughlin
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
| | - Kenton Lysak
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
| | - Lucie Debeffe
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
| | - Thomas Perry
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
| | - Keith A Hobson
- Environment Canada, 11 Innovation Boulevard, Saskatoon, Saskatchewan, S7N 3H5, Canada.,Department of Biology, University of Western Ontario, London, Ontario, N6A 5B7, Canada
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8
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Early Acacia invasion in a sandy ecosystem enables shading mediated by soil, leaf nitrogen and facilitation. Biol Invasions 2017. [DOI: 10.1007/s10530-017-1647-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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Epihov DZ, Batterman SA, Hedin LO, Leake JR, Smith LM, Beerling DJ. N 2-fixing tropical legume evolution: a contributor to enhanced weathering through the Cenozoic? Proc Biol Sci 2017; 284:20170370. [PMID: 28814651 PMCID: PMC5563791 DOI: 10.1098/rspb.2017.0370] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 07/12/2017] [Indexed: 11/30/2022] Open
Abstract
Fossil and phylogenetic evidence indicates legume-rich modern tropical forests replaced Late Cretaceous palm-dominated tropical forests across four continents during the early Cenozoic (58-42 Ma). Tropical legume trees can transform ecosystems via their ability to fix dinitrogen (N2) and higher leaf N compared with non-legumes (35-65%), but it is unclear how their evolutionary rise contributed to silicate weathering, the long-term sink for atmospheric carbon dioxide (CO2). Here we hypothesize that the increasing abundance of N2-fixing legumes in tropical forests amplified silicate weathering rates by increased input of fixed nitrogen (N) to terrestrial ecosystems via interrelated mechanisms including increasing microbial respiration and soil acidification, and stimulating forest net primary productivity. We suggest the high CO2 early Cenozoic atmosphere further amplified legume weathering. Evolution of legumes with high weathering rates was probably driven by their high demand for phosphorus and micronutrients required for N2-fixation and nodule formation.
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Affiliation(s)
- Dimitar Z Epihov
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Sarah A Batterman
- School of Geography and Priestley International Centre for Climate, University of Leeds, Leeds LS2 9JT, UK
- Smithsonian Tropical Research Institute, Balboa, Ancon, Panama
| | - Lars O Hedin
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Jonathan R Leake
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Lisa M Smith
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
| | - David J Beerling
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK
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10
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Hellmann C, Große-Stoltenberg A, Thiele J, Oldeland J, Werner C. Heterogeneous environments shape invader impacts: integrating environmental, structural and functional effects by isoscapes and remote sensing. Sci Rep 2017; 7:4118. [PMID: 28646189 PMCID: PMC5482842 DOI: 10.1038/s41598-017-04480-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 05/22/2017] [Indexed: 11/19/2022] Open
Abstract
Spatial heterogeneity of ecosystems crucially influences plant performance, while in return plant feedbacks on their environment may increase heterogeneous patterns. This is of particular relevance for exotic plant invaders that transform native ecosystems, yet, approaches integrating geospatial information of environmental heterogeneity and plant-plant interaction are lacking. Here, we combined remotely sensed information of site topography and vegetation cover with a functional tracer of the N cycle, δ15N. Based on the case study of the invasion of an N2-fixing acacia in a nutrient-poor dune ecosystem, we present the first model that can successfully predict (R 2 = 0.6) small-scale spatial variation of foliar δ15N in a non-fixing native species from observed geospatial data. Thereby, the generalized additive mixed model revealed modulating effects of heterogeneous environments on invader impacts. Hence, linking remote sensing techniques with tracers of biological processes will advance our understanding of the dynamics and functioning of spatially structured heterogeneous systems from small to large spatial scales.
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Affiliation(s)
- Christine Hellmann
- Ecosystem Physiology, University of Freiburg, Georges-Köhler-Allee 53/54, 79110, Freiburg, Germany
- Experimental and Systems Ecology, University of Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - André Große-Stoltenberg
- Institute of Landscape Ecology, University of Münster, Heisenbergstraße 2, 48149, Münster, Germany
| | - Jan Thiele
- Institute of Landscape Ecology, University of Münster, Heisenbergstraße 2, 48149, Münster, Germany
| | - Jens Oldeland
- Biodiversity, Ecology and Evolution of Plants, Biocentre Klein Flottbek and Botanical Garden, University of Hamburg, Ohnhorststraße 18, 22609, Hamburg, Germany
| | - Christiane Werner
- Ecosystem Physiology, University of Freiburg, Georges-Köhler-Allee 53/54, 79110, Freiburg, Germany.
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11
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López-Núñez FA, Heleno RH, Ribeiro S, Marchante H, Marchante E. Four-trophic level food webs reveal the cascading impacts of an invasive plant targeted for biocontrol. Ecology 2017; 98:782-793. [DOI: 10.1002/ecy.1701] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 10/21/2016] [Accepted: 11/29/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Francisco A. López-Núñez
- Centre for Functional Ecology; Department of Life Sciences; University of Coimbra; Calçada Martim de Freitas 3000-456 Coimbra Portugal
| | - Ruben H. Heleno
- Centre for Functional Ecology; Department of Life Sciences; University of Coimbra; Calçada Martim de Freitas 3000-456 Coimbra Portugal
| | - Sérgio Ribeiro
- Centre for Functional Ecology; Department of Life Sciences; University of Coimbra; Calçada Martim de Freitas 3000-456 Coimbra Portugal
| | - Hélia Marchante
- Centre for Functional Ecology; Department of Life Sciences; University of Coimbra; Calçada Martim de Freitas 3000-456 Coimbra Portugal
- Department of Environment; Coimbra Polytechnic Institute, Higher School of Agriculture; Bencanta 3045-601 Coimbra Portugal
| | - Elizabete Marchante
- Centre for Functional Ecology; Department of Life Sciences; University of Coimbra; Calçada Martim de Freitas 3000-456 Coimbra Portugal
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12
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13
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Hellmann C, Rascher KG, Oldeland J, Werner C. Isoscapes resolve species-specific spatial patterns in plant-plant interactions in an invaded Mediterranean dune ecosystem. TREE PHYSIOLOGY 2016; 36:1460-1470. [PMID: 27587484 DOI: 10.1093/treephys/tpw075] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 07/02/2016] [Accepted: 07/12/2016] [Indexed: 06/06/2023]
Abstract
Environmental heterogeneity and plant-plant interactions are key factors shaping plant communities. However, the spatial dimension of plant-plant interactions has seldom been addressed in field studies. This is at least partially rooted in a lack of methods that can accurately resolve functional processes in a spatially explicit manner. Isoscapes, that is, spatially explicit representations of stable isotope data, provide a versatile means to trace functional changes on spatial scales, for example, related to N-cycling (foliar δ15N) and water use efficiency (WUEi, foliar δ13C). In a case study in a nutrient-depleted Mediterranean dune ecosystem, we analysed the spatial impact of the invasive N2-fixing Acacia longifolia on three native species of different functional types using δ15N and δ13C isoscapes and spatial autocorrelation analyses. Isoscapes revealed strong spatial patterns in δ15N and δ13C with pronounced species-specific differences, demonstrating distinct spatial ranges of plant-plant interactions. A coniferous tree and an ericaceous dwarf shrub showed significant enrichment in δ15N within a range of 5-8 m surrounding the canopy of A. longifolia, indicating input of N originating from symbiotic N2-fixation by the invader. In the dwarf shrub, which was most responsive to invader influence, enrichment in δ13C additionally demonstrated spatially explicit changes to WUEi, while a native N2-fixer was unresponsive to the presence of the invader. Furthermore, δ15N and δ13C isoscapes yielded different patterns, indicating that plant-plant interactions can have distinct spatial distributions and ranges based on the process measured. Additionally, the magnitude of the effect differed between field situations with high and low invasion pressure. This study highlights that the spatial scale must be accounted for when assessing the effects and outcome of species interactions. Functional tracers such as stable isotopes enable us to quantify spatial ranges of plant-plant interactions, providing empirical data that can help to better understand and predict complex species interactions in multifaceted natural environments.
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Affiliation(s)
- Christine Hellmann
- Experimental and Systems Ecology, University of Bielefeld, Universitätsstraße 25, 33615 Bielefeld, Germany
- Department of Ecosystem Physiology, University of Freiburg, Georges-Köhler-Allee 53/54, 79110, Freiburg, Germany
| | - Katherine G Rascher
- Department of Ecosystem Physiology, University of Freiburg, Georges-Köhler-Allee 53/54, 79110, Freiburg, Germany
| | - Jens Oldeland
- Biodiversity, Evolution and Ecology of Plants, Biocentre Klein Flottbek and Botanical Garden, University of Hamburg, Ohnhorststraße 18, 22609, Hamburg, Germany
| | - Christiane Werner
- Department of Ecosystem Physiology, University of Freiburg, Georges-Köhler-Allee 53/54, 79110, Freiburg, Germany
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14
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Cheesman AW, Cernusak LA. Isoscapes: a new dimension in community ecology. TREE PHYSIOLOGY 2016; 36:1456-1459. [PMID: 27756872 DOI: 10.1093/treephys/tpw099] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 09/09/2016] [Accepted: 09/22/2016] [Indexed: 06/06/2023]
Affiliation(s)
- Alexander W Cheesman
- Terrestrial Ecology Group, College of Science and Engineering, James Cook University, Cairns, Queensland 4870, Australia
| | - Lucas A Cernusak
- Terrestrial Ecology Group, College of Science and Engineering, James Cook University, Cairns, Queensland 4870, Australia
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15
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Ulm F, Hellmann C, Cruz C, Máguas C. N/P imbalance as a key driver for the invasion of oligotrophic dune systems by a woody legume. OIKOS 2016. [DOI: 10.1111/oik.03810] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Florian Ulm
- Faculdade de Ciencias da Universidade de Lisboa, Centre for Ecology, Evolution and Environmental Changes; Campo Grande, C2 PT-1749-016 Lisbon Portugal
| | - Christine Hellmann
- Experimental and Systems Ecology; Univ. of Bielefeld; Bielefeld Germany
- Dept of Ecosystem Physiology; Univ. of Freiburg; Freiburg Germany
| | - Cristina Cruz
- Faculdade de Ciencias da Universidade de Lisboa, Centre for Ecology, Evolution and Environmental Changes; Campo Grande, C2 PT-1749-016 Lisbon Portugal
| | - Cristina Máguas
- Faculdade de Ciencias da Universidade de Lisboa, Centre for Ecology, Evolution and Environmental Changes; Campo Grande, C2 PT-1749-016 Lisbon Portugal
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16
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Hellmann C, Werner C, Oldeland J. A Spatially Explicit Dual-Isotope Approach to Map Regions of Plant-Plant Interaction after Exotic Plant Invasion. PLoS One 2016; 11:e0159403. [PMID: 27462988 PMCID: PMC4963087 DOI: 10.1371/journal.pone.0159403] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 07/02/2016] [Indexed: 11/19/2022] Open
Abstract
Understanding interactions between native and invasive plant species in field settings and quantifying the impact of invaders in heterogeneous native ecosystems requires resolving the spatial scale on which these processes take place. Therefore, functional tracers are needed that enable resolving the alterations induced by exotic plant invasion in contrast to natural variation in a spatially explicit way. 15N isoscapes, i.e., spatially referenced representations of stable nitrogen isotopic signatures, have recently provided such a tracer. However, different processes, e.g. water, nitrogen or carbon cycles, may be affected at different spatial scales. Thus multi-isotope studies, by using different functional tracers, can potentially return a more integrated picture of invader impact. This is particularly true when isoscapes are submitted to statistical methods suitable to find homogeneous subgroups in multivariate data such as cluster analysis. Here, we used model-based clustering of spatially explicit foliar δ15N and δ13C isoscapes together with N concentration of a native indicator species, Corema album, to map regions of influence in a Portuguese dune ecosystem invaded by the N2-fixing Acacia longifolia. Cluster analysis identified regions with pronounced alterations in N budget and water use efficiency in the native species, with a more than twofold increase in foliar N, and δ13C and δ15N enrichment of up to 2‰ and 8‰ closer to the invader, respectively. Furthermore, clusters of multiple functional tracers indicated a spatial shift from facilitation through N addition in the proximity of the invader to competition for resources other than N in close contact. Finding homogeneous subgroups in multi-isotope data by means of model-based cluster analysis provided an effective tool for detecting spatial structure in processes affecting plant physiology and performance. The proposed method can give an objective measure of the spatial extent of influence of plant-plant interactions, thus improving our understanding of spatial pattern and interactions in plant communities.
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Affiliation(s)
- Christine Hellmann
- Experimental and Systems Ecology, University of Bielefeld, Bielefeld, Germany
- Ecosystem Physiology, University of Freiburg, Freiburg im Breisgau, Germany
| | - Christiane Werner
- Ecosystem Physiology, University of Freiburg, Freiburg im Breisgau, Germany
| | - Jens Oldeland
- Biodiversity, Evolution and Ecology of Plants, Biocentre Klein Flottbek and Botanical Garden, University of Hamburg, Hamburg, Germany
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Nitzsche KN, Verch G, Premke K, Gessler A, Kayler ZE. Visualizing land‐use and management complexity within biogeochemical cycles of an agricultural landscape. Ecosphere 2016. [DOI: 10.1002/ecs2.1282] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Kai Nils Nitzsche
- Institute for Landscape Biogeochemistry Leibniz Center for Agricultural Landscape Research (ZALF) Eberswalder Str. 84 Muencheberg 15374 Germany
| | - Gernot Verch
- Research Station Dedelow Leibniz Center for Agricultural Landscape Research (ZALF) Steinfurther Str. 14 17291 Prenzlau Germany
| | - Katrin Premke
- Institute for Landscape Biogeochemistry Leibniz Center for Agricultural Landscape Research (ZALF) Eberswalder Str. 84 Muencheberg 15374 Germany
- Leibniz‐Institute of Freshwater Ecology and Inland Fisheries Mueggelseedamm 310 12587 Berlin Germany
| | - Arthur Gessler
- Institute for Landscape Biogeochemistry Leibniz Center for Agricultural Landscape Research (ZALF) Eberswalder Str. 84 Muencheberg 15374 Germany
- Swiss Federal Institute for Forest Snow and Landscape Research (WSL) Zuercherstrasse 111 8903 Birmensdorf Switzerland
- Berlin‐Brandenburg Institute of Advanced Biodiversity Research (BBIB) 14195 Berlin Germany
| | - Zachary E. Kayler
- Institute for Landscape Biogeochemistry Leibniz Center for Agricultural Landscape Research (ZALF) Eberswalder Str. 84 Muencheberg 15374 Germany
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18
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Evaluation of Continuous VNIR-SWIR Spectra versus Narrowband Hyperspectral Indices to Discriminate the Invasive Acacia longifolia within a Mediterranean Dune Ecosystem. REMOTE SENSING 2016. [DOI: 10.3390/rs8040334] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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19
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Zhang HY, Yu Q, Lü XT, Trumbore SE, Yang JJ, Han XG. Impacts of leguminous shrub encroachment on neighboring grasses include transfer of fixed nitrogen. Oecologia 2016; 180:1213-22. [PMID: 26747268 PMCID: PMC4819502 DOI: 10.1007/s00442-015-3538-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 12/21/2015] [Indexed: 10/31/2022]
Abstract
Shrub encroachment induced by global change and human disturbance strongly affects ecosystem structure and function. In this study, we explore the degree to which invading leguminous shrubs affected neighboring grasses, including via the transfer of fixed nitrogen (N). We measured N concentrations and natural abundance (15)N of shoot tissues from three dominant grasses from different plant functional groups across seven distances along a local transect (up to 500 cm) to the leguminous shrub, Caragana microphylla. C. microphylla did transfer fixed N to neighboring grasses, but the amount and distance of N transferred were strongly species-specific. Shoot N concentrations decreased significantly with distance from C. microphylla, for a rhizomatous grass, Leymus chinensis, and a bunchgrass, Achnatherum sibiricum. However, N concentrations of another bunchgrass, Stipa grandis, were higher only directly underneath the shrub canopy. Shoot δ(15)N values of L. chinensis were enriched up to 500 cm from the shrub, but for S. grandis were enriched only below the shrub canopy. In contrast, δ(15)N of A. sibiricum did not change along the 500-cm transect. Our results indicated the rhizomatous grass transferred fixed N over long distances while bunchgrasses did not. The presence of C. microphylla increased the shoot biomass of L. chinensis but decreased that of S. grandis and A. sibiricum. These findings highlight the potential role of nutrient-acquisition strategies of neighboring grasses in moderating the interspecific variation of fixed N transfer from the leguminous shrub. Overall, leguminous shrubs have either positive or negative effects on the neighboring grasses and dramatically affect plant community composition and structure.
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Affiliation(s)
- Hai-Yang Zhang
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China.
- Max Planck Institute for Biogeochemistry, 07745, Jena, Germany.
| | - Qiang Yu
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China.
- Department of Biology, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Xiao-Tao Lü
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China
| | | | - Jun-Jie Yang
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China
| | - Xing-Guo Han
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110164, China.
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20
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Nielsen JA, Frew RD, Whigham PA, Callaway RM, Dickinson KJM. Thyme travels:15N isoscapes ofThymus vulgaris L. invasion in lightly grazed pastoral communities. AUSTRAL ECOL 2015. [DOI: 10.1111/aec.12284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- J. A. Nielsen
- Department of Botany; University of Otago; Dunedin New Zealand
- 16975 Colony Lakes Blvd Fort Myers Florida 33908
| | - R. D. Frew
- Department of Chemistry; University of Otago; Dunedin New Zealand
| | - P. A. Whigham
- Department of Information Science; University of Otago; Dunedin New Zealand
| | - R. M. Callaway
- Division of Biological Sciences; University of Montana; Missoula Montana USA
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Hellmann C, Große-Stoltenberg A, Lauströ V, Oldeland J, Werner C. Retrieving nitrogen isotopic signatures from fresh leaf reflectance spectra: disentangling δ(15)N from biochemical and structural leaf properties. FRONTIERS IN PLANT SCIENCE 2015; 6:307. [PMID: 25983740 PMCID: PMC4416452 DOI: 10.3389/fpls.2015.00307] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 04/17/2015] [Indexed: 06/04/2023]
Abstract
Linking remote sensing methodology to stable isotope ecology provides a promising approach to study ecological processes from small to large spatial scales. Here, we show that δ(15)N can be detected in fresh leaf reflectance spectra of field samples along a spatial gradient of increasing nitrogen input from an N2-fixing invasive species. However, in field data it is unclear whether δ(15)N directly influences leaf reflectance spectra or if the relationship is based on covariation between δ(15)N and foliar nitrogen content or other leaf properties. Using a (15)N-labeling approach, we experimentally varied δ(15)N independently of any other leaf properties in three plant species across different leaf developmental and physiological states. δ(15)N could successfully be modeled by means of partial least squares (PLSs) regressions, using leaf reflectance spectra as predictor variables. PLS models explained 53-73% of the variation in δ(15)N within species. Several wavelength regions important for predicting δ(15)N were consistent across species and could furthermore be related to known absorption features of N-containing molecular bonds. By eliminating covariation with other leaf properties as an explanation for the relationship between reflectance and δ(15)N, our results demonstrate that (15)N itself has an inherent effect on leaf reflectance spectra. Thus, our study substantiates the use of spectroscopic measurements to retrieve isotopic signatures for ecological studies and encourages future development. Furthermore, our results highlight the great potential of optical measurements for up-scaling isotope ecology to larger spatial scales.
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Affiliation(s)
- Christine Hellmann
- Experimental and Systems Ecology, University of Bielefeld, BielefeldGermany
- AgroEcosystem Research, Bayreuth Center of Ecology and Ecosystem Research, University of Bayreuth, BayreuthGermany
| | | | - Verena Lauströ
- Experimental and Systems Ecology, University of Bielefeld, BielefeldGermany
- Plant Ecology and Conservation, Institute of Botany, Geisenheim University, GeisenheimGermany
| | - Jens Oldeland
- Biodiversity, Evolution and Ecology of Plants, Biocentre Klein Flottbek and Botanical Garden, University of Hamburg, HamburgGermany
| | - Christiane Werner
- AgroEcosystem Research, Bayreuth Center of Ecology and Ecosystem Research, University of Bayreuth, BayreuthGermany
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Risk to plant health in the EU territory of the intentional release of the bud‐galling wasp Trichilogaster acaciaelongifoliae for the control of the invasive alien plant Acacia longifolia. EFSA J 2015. [DOI: 10.2903/j.efsa.2015.4079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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23
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Pfister CA, Altabet MA, Post D. Animal regeneration and microbial retention of nitrogen along coastal rocky shores. Ecology 2014. [DOI: 10.1890/13-1825.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Dudley BD, Hughes RF, Ostertag R. Groundwater availability mediates the ecosystem effects of an invasion of Prosopis pallida. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2014; 24:1954-1971. [PMID: 29185665 DOI: 10.1890/13-1262.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Groundwater levels in arid environments are dropping worldwide due to human extraction, and precipitation events are predicted to become rarer and more intense in many arid areas with global climate change. These changes will likely alter both primary productivity and plant–soil nutrient cycles. To better understand the nature of such alterations, we examined effects of groundwater availability on plant–soil nitrogen (N) cycling in areas invaded by the N-fixing phreatophyte, Prosopis pallida, on the dry leeward coast of Hawai‘i Island. Our aims were to quantify effects of groundwater availability to P. pallida on rates of litterfall N inputs and accretion in soils and to quantify effects of groundwater availability on N mineralization and leaching rates of inorganic N under natural rainfall conditions and simulated rain events. Stem water δ18O values indicate that P. pallida trees in lowland plots accessed shallow groundwater, while in upland plots they relied solely on rainfall. During drought periods, P. pallida at upland plots experienced water stress, evidenced by lower stem water potentials, higher water-use efficiency, and lower predawn photosynthetic performance than at lowland plots. Prosopis pallida basal area was 5.3 times greater at lowland plots, and these plots exhibited 17 times higher carbon (C), 24 times higher N, and 35 times higher phosphorus (P) additions via litterfall, indicating that productivity of this phreatophyte was decoupled from rainfall where groundwater was present. Total N mass in soils was 4.7 times greater where groundwater was accessible, supporting the case that groundwater access increased N2 fixation at a stand level. In contrast, N mineralization and leaching losses from soils, though substantially greater in lowland relative to upland areas, were strongly controlled by rainfall. Results provide clear examples of how invasive species with particular functional attributes (i.e., N-fixing phreatophytes) exploit otherwise inaccessible resources to dramatically alter the functioning of the systems they invade and how anthropogenic changes to hydrological processes can also alter ecosystem-level impacts of biological invasions. Results also illustrate a mechanism by which regional groundwater drawdown may reduce soil nutrient accretion and availability in arid regions.
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Rejmánek M, Richardson DM. Trees and shrubs as invasive alien species - 2013 update of the global database. DIVERS DISTRIB 2013. [DOI: 10.1111/ddi.12075] [Citation(s) in RCA: 232] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- Marcel Rejmánek
- Department of Ecology and Evolution; University of California; Davis; CA; 95616; USA
| | - David M. Richardson
- Centre for Invasion Biology; Department of Botany and Zoology; Stellenbosch University; Matieland; 7602; South Africa
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Bai E, Boutton TW, Liu F, Wu XB, Archer SR. 15N isoscapes in a subtropical savanna parkland: spatial-temporal perspectives. Ecosphere 2013. [DOI: 10.1890/es12-00187.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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