SFS Annual Meeting

5/21/2018  |   11:00 - 11:15   |  310 B

DROUGHT-INDUCED SYNCHRONY IN DESERT FISH METACOMMUNITIES: AN EXAMINATION OF THE MORAN EFFECT Investigating metacommunity dynamics in the face of hydrologic alteration is important because anomalous floods and droughts can prevent thriving populations and communities from subsidizing those that are declining. Moreover, disturbances can have a synchronizing effect on spatially-structured populations and communities, a phenomenon known as the Moran effect. Here we used spectral methods to study long-term (1976-2015) change in streamflow regimes across the American Southwest, and reveal that yearly streamflow periodicity has been decreasing due to an increased frequency and duration of supraseasonal droughts. We then analyzed the response of desert fish metacommunities to variation in supraseasonal drought intensity. To this end, we used dynamic linear models on multidecadal fish time series, and we quantified drought-induced covariation in abundance at the metapopulation (intraspecific) and metacommunity (interspecific) levels. Anomalous low flows synchronized the metacommunity via strong effects on some—but not all—species. We discuss patterns in responses in the light of species life history adaptations that are disfavored (or favored) under the novel flow regimes. Because spatial synchrony increases system-wide extirpation risk, it is critical to understand how ongoing and future droughts may disrupt compensatory dynamics in riverine networks.

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


Julian Olden (Co-Presenter/Co-Author), University of Washington, olden@uw.edu;


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5/21/2018  |   11:15 - 11:30   |  310 B

USING METACOMMUNITY SIMULATIONS TO UNDERSTAND HOW STREAM NETWORK CHARACTERISTICS CAN AFFECT MACROINVERTEBRATE COMMUNITY STABILITY AT LOCAL AND REGIONAL SCALES Empirical investigations of stream macroinvertebrate community stability have generally focused on the reach scale, and demonstrated that a site’s location within a dendritic network can influence both the biodiversity and stability of its resident assemblage. However, the underpinning of contemporary metacommunity theory is that regional-scale processes set the context for local community assembly. Current theory suggests that (a) asynchronous spatial fluctuations should lead to enhanced local and regional stability and (b) intermediate levels of dispersal connectivity are most likely to exhibit asynchronous dynamics. Here, we used a metacommunity simulation package for R (MCSim) to create numerical models representing stream macroinvertebrate communities with different dispersal rates in a variety of stream network configurations. Simulation outcomes suggest both position in the network and dispersal rate affect stability of the local community in stream networks with low branch frequency. In low-branch-frequency networks, dispersal limited metacommunities exhibit higher stability at main-stem sites, whereas metacommunities with high immigration rates show increased stability at headwater sites. However, these dynamics are not observed in high-branch-frequency networks. Overall, these results suggest the dynamics that influence both local and catchment-wide stability can be influenced by network topology.

Eric Sokol (Primary Presenter/Author), Battelle, National Ecological Observatory Network (NEON), sokole@gmail.com;
NEON Ecologist and Data Scientist

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


Bryan Brown (Co-Presenter/Co-Author), Virginia Tech, stonefly@vt.edu;


Christopher Swan (Co-Presenter/Co-Author), University of Maryland Baltimore County, cmswan@umbc.edu;


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5/21/2018  |   11:30 - 11:45   |  310 B

METAPOPULATION STABILITY IN BRANCHING RIVER NETWORKS Metapopulation stability is a critical ecological property. Although ecosystem size has been considered as a fundamental driver of metapopulation stability, current theories ignore emergent properties of branching ecosystems, such as rivers. Here, we show that a scale-independent characteristic of fractal river networks, branching complexity, stabilizes the dynamics of watershed metapopulations. We theoretically revealed that a strong association between branching complexity and metapopulation stability is a consequence of purely probabilistic processes. Furthermore, the stabilizing effect of branching complexity was consistently observed in metapopulations of four ecologically distinct riverine fishes. Hence, branching complexity may be a ubiquitous agent of metapopulation stability in branching ecosystems. The loss of such complexity may undermine resilience of metapopulations.

Akira Terui (Primary Presenter/Author), Department of Biology, University of North Carolina at Greensboro, hanabi0111@gmail.com;


Nobuo Ishiyama (Co-Presenter/Co-Author), Hokkaido University, night7mare@gmail.com;


Hirokazu Urabe (Co-Presenter/Co-Author), Hokkaido Research Institute, urabe-hirokazu@hro.or.jp;


Satoshi Ono (Co-Presenter/Co-Author), Hokkaido Research Institute, ono@hro.or.jp;


Jacques Finlay (Co-Presenter/Co-Author), University of Minnesota, jfinlay@umn.edu;


Futoshi Nakamura (Co-Presenter/Co-Author), Hokkaido University, nakaf@for.agr.hokudai.ac.jp;


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5/21/2018  |   11:45 - 12:00   |  310 B

MULTI-SCALE BIODIVERSITY DRIVES STABILITY IN MACROSYSTEMS Although it is understood that local ecosystems are embedded within larger interconnected macrosystems (e.g. riverine networks), with processes and functions interacting at multiple scales, relatively little work has empirically investigated these phenomenon. Additionally, it is of great economic importance to understand what regulates temporal stability in ecosystem services (e.g. fisheries) and disservices (e.g. disease-vectors). Here we present results from four macrosystems: mid-Atlantic stream fish, freshwater macrophytes in upper Chesapeake Bay, seagrass in lower Chesapeake Bay, and ground beetles in Phoenix, AZ. Across case studies, we found support for our hypothesis that within site stability and asynchrony combine to influence macrosystem stability, but among systems, within site stability tended to explain more temporal variation than asynchrony. Importantly, gamma-richness, mean alpha-richness, beta-diversity, and environmental heterogeneity were key underlying drivers that increased macrosystem stability. Differences among systems suggested that environmental gradients within a system may alter the relationship between regional biodiversity and macrosystem stability. Overall, this work suggests that maintaining regional biodiversity is important for promoting macrosystem stability. However, more work is needed to better understand the mechanisms driving differences among systems.

Kevin McCluney (Primary Presenter/Author), Bowling Green State University, kmcclun@bgsu.edu;


Christopher Patrick (Co-Presenter/Co-Author), Virginia Institute of Marine Science (VIMS), cpatrick@vims.edu;


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


John Sabo (Co-Presenter/Co-Author), Arizona State University, John.L.Sabo@asu.edu;


James H. Thorp (Co-Presenter/Co-Author), University of Kansas/Kansas Biological Survey, thorp@ku.edu;


Andrew Gregory (Co-Presenter/Co-Author), Bowling Green State University, agregor@bgsu.edu;


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5/21/2018  |   12:00 - 12:15   |  310 B

SPATIAL VARIATION AND ASYNCHRONY ON BRANCHING RIVER NETWORKS River geometry influences processes such as population persistence, genetic structure, and species diversity. Recent research has linked branching river geometry with asynchrony in population fluctuations across sites which, in turn, promote regional persistence and stability. However, river networks are overlain with a template of spatial environmental variation whose effects on synchrony and stability are not well characterized. Using spatially-explicit models, I explore how consumer-resource dynamics are jointly influenced by the branching nature of river networks and spatial environmental variation. A number of case studies are considered, including those where spatial variation is random as well as those where model parameters vary with respect to network position. In the absence of spatial variation, consumer-resource fluctuations synchronize across clusters of linked local habitats; the size of these clusters and degree of asynchrony among them strongly influences regional stability. Random spatial variation tends to interrupt clustering among local habitats, while spatial variation linked to network position typically enhances it. However, the effects on regional stability can be somewhat idiosyncratic in both cases. Spatial shifts in parameter values can lead to local stability at certain sites without necessarily greatly contributing to stability regionally.

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


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5/21/2018  |   12:15 - 12:30   |  310 B

ANALYZING NEOTROPICAL DIATOM METACOMMUNITIES ACROSS SPACE AND TIME Determining mechanisms of community assembly in high-elevation lakes is key to anticipating global change impacts in these sentinel ecosystems. However, such mechanisms are difficult to study using environmental and/or spatial variables from only snapshot sampling, given the complex spatial-temporal mechanisms of community assembly, as well as differential functional traits of target species. This study focuses on tropical lakes of South America, which are key systems in fulfilling important ecological and economic functions for Andean societies over the millennia. Our overarching question is: what insights do historical changes in the paleolimnological record provide on present diatom metacommunities? This question is being addressed using complementary approaches that span a range of spatial and temporal scales. First, a diatom-guild metacommunity model is used to examine niche- and dispersal-based assembly processes that structure diatom communities across the tropical Andes. Second, single-species distributions are modelled incorporating historical legacies of diatom communities in lakes of Ecuador to aid interpretations of mechanisms driving recent limnological change. This novel framework should advance the applicability of metacommunity theory to evaluate the resilience of complex natural systems and also provide tools for well-informed management and conservation strategies for tropical lakes.

Xavier Benito (Primary Presenter/Author), University of Nebraska-Lincoln, xbenitogranell2@unl.edu;


Sherilyn Fritz (Co-Presenter/Co-Author), University of Nebraska-Lincoln, sfritz2@unl.edu;


Miriam Steinitz-Kannan (Co-Presenter/Co-Author), Northern Kentucky University, kannan@nku.edu;


Maria Vélez (Co-Presenter/Co-Author), University of Regina, maria.velez@uregina.ca;


Michael McGlue (Co-Presenter/Co-Author), University of Kentucky, mmmc234@g.uky.edu;


Melina Feitl (Co-Presenter/Co-Author), University of Nebraska, mfeitl@huskers.unl.edu;


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