SFS Annual Meeting

5/23/2019  |   11:00 - 11:15   |  151 G

DISTANCE DECAY OF SIMILARITY IN STREAM INVERTEBRATE COMMUNITIES: CLIMATIC INFLUENCES OVER SPACE AND TIME A fundamental concept in metacommunity ecology is the distance decay of similarity (DDS). DDS occurs because local communities from distant habitats tend to be more compositionally dissimilar due to the combined effects of environmental gradients, dispersal barriers, and ecological drift. Research on the topic has largely assessed DDS across geographic gradients. Although time-varying environmental forcing could drive temporal variation in DDS, this idea remains untested. Here we used stream macroinvertebrate data from the California Surface Water Ambient Monitoring Program (SWAMP) to analyze the DDS within different hydrologic regions of California, and for a period of eight years (2008-2015). This time span includes periods of drought and average precipitation. We observed that DDS in reference sites varied across years and hydrologic regions, with slopes being steeper in northern areas and particularly during drought. We also tested whether anthropogenic hydrologic alteration could dampen the effects of hydroclimatic fluctuations by comparing patterns obtained from reference and non-reference sites. Our work advances the notion that invertebrate metacommunity structure in streams is time-varying, and may respond to periodic fluctuations in environmental conditions and habitat connectivity.

Guillermo de Mendoza (Primary Presenter/Author), Institute of Geography, Faculty of Oceanography and Geography, University of Gdansk, gdemendoza.eco@gmail.com;


David B. Herbst (Co-Presenter/Co-Author), Institute of Marine Sciences, University of California Santa Cruz, and Sierra Nevada Aquatic Research Laboratory, University of California Santa Barbara, herbst@lifesci.ucsb.edu;


Albert Ruhi (Co-Presenter/Co-Author), Department of Environmental Science, Policy, and Management, University of California, Berkeley, albert.ruhi@berkeley.edu;


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5/23/2019  |   11:15 - 11:30   |  151 G

ACROSS ECOSYSTEM INFLUENCES ON AQUATIC BIODIVERSITY IN HIGH ELEVATION LAKE STREAM NETWORKS Aquatic biodiversity is hypothesized to be differentially structured across habitat types. However, our understanding of how ecosystem linkages and the extent of spatial scale influence ecological processes structuring biodiversity remains largely unresolved. In this study, I investigate how stream macroinvertebrate diversity is structured across aquatic ecosystems in high elevation lake-stream networks throughout the Sierra Nevada. Lake-stream networks have unique environmental conditions and the differences among catchments explains a large proportion of environmental variation. Within networks, the strong effect of landscape position suggests that environments are changing along a gradient from headwater sites moving down the catchment. Lakes have two primary effects on stream macroinvertebrate communities. Lakes have a homogenizing effect on community and functional diversity at the stream outlets and this influence is reduced moving downstream from the lake. Secondly, lakes are barriers to dispersal for some macroinvertebrate species. Despite connectivity across lakes and streams, the spatial and environmental gradients presented by lakes may influence species dispersal. This research should provide important insights into how biodiversity is structured across connected ecosystems and across spatial scales, especially in light of climate driven hydrological changes to high elevation aquatic ecosystems.

Kurt Anderson (Co-Presenter/Co-Author), University of California, Riverside, kurt.anderson@ucr.edu;


Matthew Green (Primary Presenter/Author), University of California Riverside, mgree013@ucr.edu;


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5/23/2019  |   11:30 - 11:45   |  151 G

SPATIAL HOMOGENIZATION OF MAYFLY, STONEFLY AND CADDISFLY ASSEMBLAGES IN SWISS RUNNING WATERS IN THE FACE OF GLOBAL WARMING Several studies assessed stream macroinvertebrates in the Swiss Alps but few focused on lower regions and none on beta-diversity at the countrywide scale. Our main goals were to predict the pattern of mayfly, stonefly and caddisfly (EPT) diversity across Switzerland and to assess the impact of warming temperatures on compositional heterogeneity. We used Generalized Dissimilarity Modeling to analyze the spatial turnover of EPT assemblages from samples covering the entire country. Climatic, topographic, geologic and land use variables were used as predictors. Contrasted climate change scenarios were used for future predictions. Results showed the largest amount of EPT turnover occurred along the air temperature and slope gradients. These variables represented good proxies for water temperature and hydrologic constraints, usually regarded as main drivers of aquatic macroinvertebrate diversity. We predicted a biotic homogenization with increasing temperatures due to the upstream expansion of assemblages from the sub-montane level. This study allowed the first countrywide prediction of EPT composition patterns and provided insights into the vulnerability to warming temperatures of assemblages occurring at high elevations. Our results support the urgency of immediate and significant reductions of greenhouse gases to limit compositional homogenization in the long term.

Pablo Timoner (Primary Presenter/Author), University of Geneva, pablo.timoner@unige.ch;


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5/23/2019  |   11:45 - 12:00   |  151 G

METACOMMUNITY STRUCTURING OF STREAM MACROINVERTEBRATES IN THE HENGDUAN MOUNTAINS (CHINA) Metacommunity structures are controlled by the interaction of the local environment and the spatial characteristics of the region. The role that local and spatial factors play in structuring the metacommunity in high mountain streams remains unclear. We aim to investigate the contribution of river connectivity in structuring high mountain stream metacommunities between 1623m and 2904m a.s.l. in the Hengduan Mountains, a global biodiversity hotspot. The streams on the west aspect of the mountain are connected by a river, while streams on the east aspect flow into a large lake. We compared the elements and types of metacommunity structure on both aspects and determined the importance of spatial distances (i.e. Euclidean distance, topographic distance, and network distance) on metacommunity structure. Additionally, we compared community dissimilarity between upstream and downstream sites, between niche groups (generalists and specialists), and between dispersal abilities (strong and weak). Understanding the metacommunity structures that underlie high mountain streams and how river connectivity impacts them may support conservation biologists and catchment managers, helping them properly predict and combat the effects of expanding human influence and climate change the Hengduan Mountains.

Angelika Kurthen (Primary Presenter/Author), Freie Universität Berlin, Berlin Germany, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany, kurthea95@zedat.fu-berlin.de;


Fengzhi He (Co-Presenter/Co-Author), Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany & Institute of Biology, Freie Universität Berlin, Berlin, Germany & School of Geography, Queen Mary University of London, London, United Kingdom, fengzhi.he@igb-berlin.de;


Qinghua Cai (Co-Presenter/Co-Author), State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China, qhcai@ihb.ac.cn;


Sonja Jähnig (Co-Presenter/Co-Author), Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany, sonja.jaehnig@igb-berlin.de;


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5/23/2019  |   12:15 - 12:30   |  151 G

THE ECOLOGY OF ENDANGERED BRANCHIOPODA IN ROCK POOL METACOMMUNITIES Metacommunity ecology is a framework addressing interacting species that occur in a set of local communities linked by dispersal. Few studies have assessed endangered species distribution and abundance in this context. Endangered branchiopods, Branchinecta longiantenna and Branchinecta lynchi, are found throughout California in temporary ponds and wetlands, including rock pools. Little is known of their ecology and especially as it relates to their interactions with habitat features, water chemistry, and other species. We evaluated species’ patterns using three years of abiotic and biotic survey data of rock pools in Contra Costa and Alameda Counties, CA. Branchinecta lynchi was ubiquitous after inundation, while Branchinecta longiantenna emerged later and in fewer pools. Both populations were associated with pool volume, biodiversity (competitors and predators), and various water variables, and the relationships changed with time. Distribution patterns suggested B. lynchi was not limited by dispersal, while B. longiantenna was more limited by dispersal and environmental factors. These results highlight the importance of local and metacommunity dynamics for endangered species ecology.

Jamie Kneitel (Primary Presenter/Author), California State University, Sacramento, kneitel@csus.edu;


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