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Zhang P, Huang M, Chen C, Hu K, Ke J, Liu M, Xiao Y, Liu X. Contrasting roles of fungal and oomycete pathogens in mediating nitrogen addition and winter grazing effects on biomass. Ecology 2024; 105:e4254. [PMID: 38272568 DOI: 10.1002/ecy.4254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 10/26/2023] [Accepted: 12/21/2023] [Indexed: 01/27/2024]
Abstract
Both bottom-up and top-down processes modulate plant communities. Fungal and oomycete pathogens are most common in global grasslands, and due to differences in their physiology, function, host range, and life cycles, they may differentially affect plants (in both intensity and direction). However, how fungal and oomycete pathogens regulate bottom-up and top-down effects on plant community biomass remains unclear. To this end, we conducted a 3-year field experiment in an alpine meadow incorporating mammalian herbivore exclosure, fungicide/oomyceticide application, and nitrogen addition treatments. We arranged 12 blocks with half randomly assigned to be mammalian herbivore exclosures (fenced to exclude grazing sheep), and the other half were fenced most of the year but not in winter (winter grazing control). Six 2.5 × 2.5 m square plots were established in each block, with each of the six plots assigned as control, nitrogen addition, fungicide application, oomyceticide application, nitrogen addition + fungicide application, and nitrogen addition + oomyceticide application. We found that fungicide application significantly increased plant community biomass (mainly Poaceae species) under nitrogen addition and promoted the bottom-up effect of nitrogen addition on plant community biomass by altering the community-weighted mean of plant height (via species turnover). Meanwhile, oomyceticide application significantly increased plant community biomass (mainly Poaceae species) when mammalian herbivores were excluded and weakened the top-down effect of winter grazing on plant community biomass by driving intraspecific variation in plant height. Our results highlight that fungal and oomycete pathogens play important (but differing) roles in mediating the effects of nutrient availability and higher trophic levels on plant community biomass. Mechanistically, we demonstrated that plant pathogen-related modulation of plant community biomass is achieved by alterations to plant height. Overall, this study combines both community and disease ecology to reveal complex interactions among higher trophic levels and their potential impacts on terrestrial ecosystem functioning under human disturbance.
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Affiliation(s)
- Peng Zhang
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, P. R. China
| | - Mengjiao Huang
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, P. R. China
| | - Chaorui Chen
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, P. R. China
| | - Kui Hu
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, P. R. China
| | - Junsheng Ke
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, P. R. China
| | - Mu Liu
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, P. R. China
| | - Yao Xiao
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, P. R. China
| | - Xiang Liu
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, P. R. China
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2
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Carroll EW, Freestone AL. Habitat isolation interacts with top-down and bottom-up processes in a seagrass ecosystem. PLoS One 2023; 18:e0289174. [PMID: 37494351 PMCID: PMC10370773 DOI: 10.1371/journal.pone.0289174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 07/12/2023] [Indexed: 07/28/2023] Open
Abstract
Habitat loss is accelerating at unprecedented rates, leading to the emergence of smaller, more isolated habitat remnants. Habitat isolation adversely affects many ecological processes independently, but little is known about how habitat isolation may interact with ecosystem processes such as top-down (consumer-driven) and bottom-up (resource-driven) effects. To investigate the interactive influence of habitat isolation, resource availability and consumer distribution and impact on community structure, we tested two hypotheses using invertebrate and algal epibionts on temperate seagrasses, an ecosystem of ecological and conservation importance. First, we hypothesized that habitat isolation will change the structure of the seagrass epibiont community, and isolated patches of seagrass will have lower epibiont biomass and different epibiont community composition than contiguous meadows. Second, we hypothesized that habitat isolation would mediate top-down (i.e., herbivory) and bottom-up (i.e., nutrient enrichment) control for algal epibionts. We used observational studies in natural seagrass patches and experimental artificial seagrass to examine three levels of habitat isolation. We further manipulated top-down and bottom-up processes in artificial seagrass through consumer reductions and nutrient additions, respectively. We indeed found that habitat isolation of seagrass patches decreased epibiont biomass and modified epibiont community composition. This pattern was largely due to dispersal limitation of invertebrate epibionts that resulted in a decline in their abundance and richness in isolated patches. Further, habitat isolation reduced consumer abundances, weakening top-down control of algal epibionts in isolated seagrass patches. Nutrient additions, however, reversed this pattern, and allowed a top-down effect on algal richness to emerge in isolated habitats, demonstrating a complex interaction between patch isolation and top-down and bottom-up processes. Habitat isolation may therefore shape the relative importance of central processes in ecosystems, leading to changes in community composition and food web structure in marine habitats.
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Affiliation(s)
- Elizabeth W Carroll
- Department of Biology, Holy Family University, Philadelphia, Pennsylvania, United States of America
| | - Amy L Freestone
- Department of Biology, Temple University, Philadelphia, Pennsylvania, United States of America
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3
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Dolezal AJ, Esch EH, MacDougall AS. Restored marginal farmland benefits arthropod diversity at multiple scales. Restor Ecol 2021. [DOI: 10.1111/rec.13485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Aleksandra J. Dolezal
- University of Guelph, Department of Integrative Biology, 50 Stone Road East Guelph Ontario Canada N1G 2W1
| | - Ellen H. Esch
- University of Guelph, Department of Integrative Biology, 50 Stone Road East Guelph Ontario Canada N1G 2W1
| | - Andrew S. MacDougall
- University of Guelph, Department of Integrative Biology, 50 Stone Road East Guelph Ontario Canada N1G 2W1
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4
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Morimoto J, Pietras Z. Strong foraging preferences for Ribes alpinum (Saxifragales: Grossulariaceae) in the polyphagous caterpillars of Buff-tip moth Phalera bucephala (Lepidoptera: Notodontidae). Ecol Evol 2020; 10:13583-13592. [PMID: 33391664 PMCID: PMC7771136 DOI: 10.1002/ece3.6981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/28/2020] [Accepted: 10/13/2020] [Indexed: 11/26/2022] Open
Abstract
Herbivorous insects such as butterflies and moths are essential to natural and agricultural systems due to pollination and pest outbreaks. However, our knowledge of butterflies' and moths' nutrition is fragmented and limited to few common, charismatic, or problematic species.This gap precludes our complete understanding of herbivorous insects' natural history, physiological and behavioral adaptations that drive how species interact with their environment, the consequences of habitat fragmentation and climate change to invertebrate biodiversity, and pest outbreak dynamics.Here, we first report a population of the Buff-tip moth Phalera bucephala (Lepidoptera: Notodontidae) feeding on a previously unknown family of host plants, the mountain currant Ribes alpinum (Saxifragales: Grossulariaceae). This is the first report of a Notodontid moth feeding on Grossulariaceae hosts.Using no-choice and choice assays, we showed that P. bucephala has strong foraging preferences for a previously unknown hosts, the R. alpinum but also, although to a smaller extent, R. uva-crispa compared with a previously known host (the Norway maple Acer sp.).These findings demonstrate that P. bucephala feed on-and show strong preference for Grossulariaceae host plants, indicating flexible physiological mechanisms to accommodate hosts plants from various families. This makes this species a potential model organism to study the behavioral and physiological mechanisms underpinning insect-plant interactions and diet breadth evolution.We discuss the broad ecological implications of these observations to the biology of the species, the potential negative effects of interspecific competition with endemic specialist moths, and highlight questions for future research.
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Affiliation(s)
| | - Zuzanna Pietras
- Department of Physics, Chemistry and Biology (IFM)Linköping UniversityLinköpingSweden
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Wang R, Zhang X, Shi YS, Li YY, Wu J, He F, Chen XY. Habitat fragmentation changes top-down and bottom-up controls of food webs. Ecology 2020; 101:e03062. [PMID: 32239497 DOI: 10.1002/ecy.3062] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/25/2020] [Indexed: 11/07/2022]
Abstract
Top-down and bottom-up controls regulate the structure and stability of ecosystems, but their relative roles in terrestrial systems have been debated. Here we studied a hydro-inundated land-bridge system in subtropical China and tested the relative importance of these two controls in determining the rodent-mediated regeneration of a locally dominant tree species. Our results showed that both controls operated in terrestrial habitats and that their relative importance switched as habitat size changed. Habitat loss initially removed predators of rodents that released rodent populations and triggered massive seed predation (top-down control), leading to reduced seedling establishment. A further reduction in habitat size led to decrease in rodent population that was supposed to increase seedling survival of the tree species, but the decline in habitat size deteriorated the abiotic environments (bottom-up control) that severely prevented seedling recruitment. As the ongoing global land use change is creating increasing number of small-sized forest fragments, our findings provide novel insights into the restoration of seriously fragmented forests.
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Affiliation(s)
- Rong Wang
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China.,Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Xin Zhang
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China
| | - Yi-Su Shi
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China
| | - Yuan-Yuan Li
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China
| | - Jianguo Wu
- School of Life Sciences & Global Institute of Sustainability, Arizona State University, Tempe, Arizona, 85287-4501, USA
| | - Fangliang He
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China.,Department of Renewable Resources, University of Alberta, Edmonton, Alberta, T6G 2H1, Canada
| | - Xiao-Yong Chen
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China.,Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
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6
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Godschalx AL, Rodríguez-Castañeda G, Rasmann S. Contribution of different predator guilds to tritrophic interactions along ecological clines. CURRENT OPINION IN INSECT SCIENCE 2019; 32:104-109. [PMID: 31113621 DOI: 10.1016/j.cois.2019.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 12/19/2018] [Accepted: 01/07/2019] [Indexed: 06/09/2023]
Abstract
The strengths of interactions between plants, herbivores, and predators are predicted to relax with elevation. Despite the fundamental role predators play in tritrophic interactions, high-resolution experimental evidence describing predation across habitat gradients is still scarce in the literature and varies by predator. With this opinion paper, we look at how tritrophic strength of systems including different vertebrate and invertebrate predator guilds changes with elevation. Specifically, we focus on how birds, ants, parasitoids, and nematodes exert top-down pressure as predators and propose ways, in which each group could be better understood through elevational gradient studies. We hope to enrich future perspectives for disentangling the different biotic and abiotic factors underlying predator-mediated trophic interactions in a diversity of habitats.
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Affiliation(s)
- Adrienne L Godschalx
- Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
| | | | - Sergio Rasmann
- Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland.
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7
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Stireman JO, Singer MS. Tritrophic niches of insect herbivores in an era of rapid environmental change. CURRENT OPINION IN INSECT SCIENCE 2018; 29:117-125. [PMID: 30551817 DOI: 10.1016/j.cois.2018.07.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/09/2018] [Accepted: 07/16/2018] [Indexed: 06/09/2023]
Abstract
A multi-trophic perspective improves understanding of the ecological and evolutionary consequences of rapid environmental change on insect herbivores. Loss of specialized enemies due to human impacts is predicted to dramatically reduce the number of tritrophic niches of herbivores compared to a bitrophic niche perspective. Habitat fragmentation and climate change promote the loss of both specialist enemies and herbivores, favoring ecological generalism across trophic levels. Species invasion can fundamentally alter trophic interactions toward various outcomes and contributes to ecological homogenization. Adaptive evolution on ecological timescales is expected to dampen tritrophic instabilities and diversify niches, yet its ability to compensate for tritrophic niche losses in the short term is unclear.
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Affiliation(s)
- John O Stireman
- Department of Biological Sciences, Wright State University, Dayton, OH 45435, USA.
| | - Michael S Singer
- Department of Biology, Wesleyan University, Middletown, CT 06459, USA
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8
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Harvey E, MacDougall AS. Non-interacting impacts of fertilization and habitat area on plant diversity via contrasting assembly mechanisms. DIVERS DISTRIB 2017. [DOI: 10.1111/ddi.12697] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Eric Harvey
- Department of Integrative Biology; University of Guelph; Guelph ON Canada
- Department of Ecology and Evolutionary Biology; University of Toronto; Toronto ON Canada
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Harvey E, Gounand I, Ganesanandamoorthy P, Altermatt F. Spatially cascading effect of perturbations in experimental meta-ecosystems. Proc Biol Sci 2017; 283:rspb.2016.1496. [PMID: 27629038 DOI: 10.1098/rspb.2016.1496] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 08/24/2016] [Indexed: 11/12/2022] Open
Abstract
Ecosystems are linked to neighbouring ecosystems not only by dispersal, but also by the movement of subsidy. Such subsidy couplings between ecosystems have important landscape-scale implications because perturbations in one ecosystem may affect community structure and functioning in neighbouring ecosystems via increased/decreased subsidies. Here, we combine a general theoretical approach based on harvesting theory and a two-patch protist meta-ecosystem experiment to test the effect of regional perturbations on local community dynamics. We first characterized the relationship between the perturbation regime and local population demography on detritus production using a mathematical model. We then experimentally simulated a perturbation gradient affecting connected ecosystems simultaneously, thus altering cross-ecosystem subsidy exchanges. We demonstrate that the perturbation regime can interact with local population dynamics to trigger unexpected temporal variations in subsidy pulses from one ecosystem to another. High perturbation intensity initially led to the highest level of subsidy flows; however, the level of perturbation interacted with population dynamics to generate a crash in subsidy exchange over time. Both theoretical and experimental results show that a perturbation regime interacting with local community dynamics can induce a collapse in population levels for recipient ecosystems. These results call for integrative management of human-altered landscapes that takes into account regional dynamics of both species and resource flows.
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Affiliation(s)
- Eric Harvey
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland Department of Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Isabelle Gounand
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland Department of Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Pravin Ganesanandamoorthy
- Department of Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Florian Altermatt
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland Department of Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
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10
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Ord TJ, Emblen J, Hagman M, Shofner R, Unruh S. Manipulation of habitat isolation and area implicates deterministic factors and limited neutrality in community assembly. Ecol Evol 2017; 7:5845-5860. [PMID: 28811885 PMCID: PMC5552957 DOI: 10.1002/ece3.3126] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/03/2017] [Accepted: 05/08/2017] [Indexed: 11/12/2022] Open
Abstract
Theory predicts deterministic and stochastic factors will contribute to community assembly in different ways: Environmental filters should regulate those species that establish in a particular area resulting in the ecological requirements of species being the primary driver of species distributions, while chance and dispersal limitation should dictate the likelihood of species reaching certain areas with the ecology of species being largely neutral. These factors are specifically relevant for understanding how the area and isolation of different habitats or islands interact to affect community composition. Our review of the literature found few experimental studies have examined the interactive effect of habitat area and isolation on community assembly, and the results of those experiments have been mixed. We manipulated the area and isolation of rock “islands” created de novo in a grassland matrix to experimentally test how deterministic and stochastic factors shape colonizing animal communities. Over 64 weeks, the experiment revealed the primacy of deterministic factors in community assembly, with habitat islands of the same size exhibiting remarkable consistency in community composition and diversity, irrespective of isolation. Nevertheless, tangible differences still existed in abundance inequality among taxa: Large, near islands had consistently higher numbers of common taxa compared to all other island types. Dispersal limitation is often assumed to be negligible at small spatial scales, but our data shows this not to be the case. Furthermore, the dispersal limitation of a subset of species has potentially complex flow‐on effects for dictating the type of deterministic factors affecting other colonizing species.
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Affiliation(s)
- Terry J Ord
- Evolution and Ecology Research Centre and the School of Biological Earth and Environmental Sciences University of New South Wales Kensington NSW Australia
| | - Jack Emblen
- Evolution and Ecology Research Centre and the School of Biological Earth and Environmental Sciences University of New South Wales Kensington NSW Australia
| | - Mattias Hagman
- Evolution and Ecology Research Centre and the School of Biological Earth and Environmental Sciences University of New South Wales Kensington NSW Australia
| | - Ryan Shofner
- Evolution and Ecology Research Centre and the School of Biological Earth and Environmental Sciences University of New South Wales Kensington NSW Australia
| | - Sara Unruh
- Evolution and Ecology Research Centre and the School of Biological Earth and Environmental Sciences University of New South Wales Kensington NSW Australia
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Affiliation(s)
- Lucy Genua
- Dept of Ecology and Evolutionary Biology, Univ. of Toronto; Toronto ON, M5S 3B3 Canada
| | - Denon Start
- Dept of Ecology and Evolutionary Biology, Univ. of Toronto; Toronto ON, M5S 3B3 Canada
| | - Benjamin Gilbert
- Dept of Ecology and Evolutionary Biology, Univ. of Toronto; Toronto ON, M5S 3B3 Canada
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12
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Harvey E, Gounand I, Ward CL, Altermatt F. Bridging ecology and conservation: from ecological networks to ecosystem function. J Appl Ecol 2016. [DOI: 10.1111/1365-2664.12769] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Eric Harvey
- Department of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190 CH-8057 Zürich Switzerland
- Department of Aquatic Ecology; Eawag: Swiss Federal Institute of Aquatic Science and Technology; Überlandstrasse 133 CH-8600 Dübendorf Switzerland
| | - Isabelle Gounand
- Department of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190 CH-8057 Zürich Switzerland
- Department of Aquatic Ecology; Eawag: Swiss Federal Institute of Aquatic Science and Technology; Überlandstrasse 133 CH-8600 Dübendorf Switzerland
| | - Colette L. Ward
- National Center for Ecological Analysis and Synthesis; University of California, Santa Barbara; 735 State Street, Suite 300 Santa Barbara CA 93101-5504 USA
| | - Florian Altermatt
- Department of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190 CH-8057 Zürich Switzerland
- Department of Aquatic Ecology; Eawag: Swiss Federal Institute of Aquatic Science and Technology; Überlandstrasse 133 CH-8600 Dübendorf Switzerland
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