Geophysical templates modulate the structure of stream food webs dominated by omnivory
Abstract Food webs show the architecture of trophic relationships, revealing the biodiversity and species interactions in an ecosystem. Understanding which factors modulate the structure of food webs offers us the ability to predict how they will change when influential factors are altered. To date,...
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Online Access: | https://doi.org/10.1002/ecs2.3444 |
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doaj-9f24d8d5a9634c2fa8c589d5a28bdd712021-04-18T21:00:39ZengWileyEcosphere2150-89252021-03-01123n/an/a10.1002/ecs2.3444Geophysical templates modulate the structure of stream food webs dominated by omnivoryLauren Zatkos0Ivan Arismendi1Sherri L. Johnson2Brooke E. Penaluna3Department of Fisheries and Wildlife Oregon State University 2820 SW Campus Way Corvallis Oregon97331USADepartment of Fisheries and Wildlife Oregon State University 2820 SW Campus Way Corvallis Oregon97331USAUSDA Forest ServicePacific Northwest Research Station 3200 Southwest Jefferson Way Corvallis Oregon97331USAUSDA Forest ServicePacific Northwest Research Station 3200 Southwest Jefferson Way Corvallis Oregon97331USAAbstract Food webs show the architecture of trophic relationships, revealing the biodiversity and species interactions in an ecosystem. Understanding which factors modulate the structure of food webs offers us the ability to predict how they will change when influential factors are altered. To date, most of the research about food webs has focused on species interactions whereas the influences of surrounding environments have been overlooked. Here, using network analysis, we identified how the structure of aquatic food webs varied across a range of geophysical conditions within a whole stream system. Within a headwater basin in the Cascade Mountain Range, Oregon, USA, macroinvertebrate and vertebrate composition was investigated at 18 sites. Predator–prey interactions were compiled based on existing literature and dietary analysis. Several structural network metrics were calculated for each food web. We show that the structure of food webs was predictable based on geophysical features at both local (i.e., slope) and broader (i.e., basin size) spatial extents. Increased omnivory, greater connectance, shorter path lengths, and ultimately greater complexity and resilience existed downstream compared to upstream in the stream network. Surprisingly, the variation in food web structure was not associated with geographic proximity. Structural metric values and abundance of omnivory suggest high levels of stability for these food webs. There is a predictable variation in the structure of food webs across the network that is influenced by both longitudinal position within streams and patchy discontinuities in habitat. Hence, findings illustrate that the slightly differing perspectives from the River Continuum Concept, Discontinuity Patch Dynamics, and Process Domains can be integrated and unified using food web networks. Our analyses extend ecologists’ understanding of the stability of food webs and are a vital step toward predicting how webs and communities may respond to both natural disturbances and current global environmental change.https://doi.org/10.1002/ecs2.3444community complexityconnectancefood web theoryheadwater streamsnetwork analysisomnivory |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Lauren Zatkos Ivan Arismendi Sherri L. Johnson Brooke E. Penaluna |
spellingShingle |
Lauren Zatkos Ivan Arismendi Sherri L. Johnson Brooke E. Penaluna Geophysical templates modulate the structure of stream food webs dominated by omnivory Ecosphere community complexity connectance food web theory headwater streams network analysis omnivory |
author_facet |
Lauren Zatkos Ivan Arismendi Sherri L. Johnson Brooke E. Penaluna |
author_sort |
Lauren Zatkos |
title |
Geophysical templates modulate the structure of stream food webs dominated by omnivory |
title_short |
Geophysical templates modulate the structure of stream food webs dominated by omnivory |
title_full |
Geophysical templates modulate the structure of stream food webs dominated by omnivory |
title_fullStr |
Geophysical templates modulate the structure of stream food webs dominated by omnivory |
title_full_unstemmed |
Geophysical templates modulate the structure of stream food webs dominated by omnivory |
title_sort |
geophysical templates modulate the structure of stream food webs dominated by omnivory |
publisher |
Wiley |
series |
Ecosphere |
issn |
2150-8925 |
publishDate |
2021-03-01 |
description |
Abstract Food webs show the architecture of trophic relationships, revealing the biodiversity and species interactions in an ecosystem. Understanding which factors modulate the structure of food webs offers us the ability to predict how they will change when influential factors are altered. To date, most of the research about food webs has focused on species interactions whereas the influences of surrounding environments have been overlooked. Here, using network analysis, we identified how the structure of aquatic food webs varied across a range of geophysical conditions within a whole stream system. Within a headwater basin in the Cascade Mountain Range, Oregon, USA, macroinvertebrate and vertebrate composition was investigated at 18 sites. Predator–prey interactions were compiled based on existing literature and dietary analysis. Several structural network metrics were calculated for each food web. We show that the structure of food webs was predictable based on geophysical features at both local (i.e., slope) and broader (i.e., basin size) spatial extents. Increased omnivory, greater connectance, shorter path lengths, and ultimately greater complexity and resilience existed downstream compared to upstream in the stream network. Surprisingly, the variation in food web structure was not associated with geographic proximity. Structural metric values and abundance of omnivory suggest high levels of stability for these food webs. There is a predictable variation in the structure of food webs across the network that is influenced by both longitudinal position within streams and patchy discontinuities in habitat. Hence, findings illustrate that the slightly differing perspectives from the River Continuum Concept, Discontinuity Patch Dynamics, and Process Domains can be integrated and unified using food web networks. Our analyses extend ecologists’ understanding of the stability of food webs and are a vital step toward predicting how webs and communities may respond to both natural disturbances and current global environmental change. |
topic |
community complexity connectance food web theory headwater streams network analysis omnivory |
url |
https://doi.org/10.1002/ecs2.3444 |
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