Monday, May 23, 2016
15:30 - 17:00

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15:30 - 15:45: / 308 THE BIODIVERSITY AND ECOHYDROLOGY OF INTERMITTENT AND EPHEMERAL RIVERS: INTRODUCING THE IRBAS DATABASE AND AN ANALYTICAL EXAMPLE

5/23/2016  |   15:30 - 15:45   |  308

THE BIODIVERSITY AND ECOHYDROLOGY OF INTERMITTENT AND EPHEMERAL RIVERS: INTRODUCING THE IRBAS DATABASE AND AN ANALYTICAL EXAMPLE Determining relationships between biodiversity and hydrology is a critical goal in ecology, particularly given the crisis in freshwater biodiversity and increasing prevalence of flow intermittence under current and future climate. The new IRBAS (Intermittent River Biodiversity Analysis and Synthesis) database provides a free service to scientists and managers to store, standardise and access biodiversity, hydrological and environmental data collected from intermittent and ephemeral rivers and their perennial counterparts, worldwide. We demonstrate the database—how to contribute and access data—and provide an example of a large-scale ecohydrological analysis using long-term data collated by the IRBAS project. We found that flow intermittence was a strong environmental filter and primary hydrological determinant of macroinvertebrate alpha-diversity; taxonomic richness declined with increasing durations of intermittence, both over the long-term and recent history of river discharge. Our predictive models improve understanding of ecohydrology and biodiversity of intermittent and ephemeral rivers in the context of climate change and future challenges. Research and management of rivers will continue to benefit from ‘big data’ collations, syntheses and analyses facilitated by the IRBAS database, as demonstrated in this presentation.

Catherine Leigh (Primary Presenter/Author), IRSTEA and CESAB, France, c.leigh@griffith.edu.au;


Thibault Datry ( Co-Presenter/Co-Author), IRSTEA/IRD, France, Thibault.datry@irstea.fr;


Working Group of IRBAS ( Co-Presenter/Co-Author), IRBAS, irbas@cesab.org;


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15:45 - 16:00: / 308 RISE UP LAZARUS! LIFE HISTORY AND DISTRIBUTION OF AN INTERMITTENT STREAM SPECIALIST (MESOCAPNIA ARIZONENSIS)

5/23/2016  |   15:45 - 16:00   |  308

RISE UP LAZARUS! LIFE HISTORY AND DISTRIBUTION OF AN INTERMITTENT STREAM SPECIALIST (MESOCAPNIA ARIZONENSIS) Though intermittent streams are common in many regions, little is known about their fauna, including the life history traits that allow this fauna to persist in streams that dry regularly. The Arizona snowfly (Mesocapnia arizonensis) was first described in 1969 and was only know from a few streams. Recently, however, I collected the species from > 40 streams across Arizona and California. The species appears to have been overlooked because it prefers short flow duration (<4 months/year) streams. To learn more about this species, I documented the life cycle of Mesocapnia arizonensis in an intermittent desert stream (Bear Canyon, Arizona). Mesocapnia arizonensis emerged from dormancy within two weeks of flow resumption and completed nymphal development, emergence, oviposition, and egg hatching in as few as seven weeks. The species appears to only have one generation per year and abruptly stopped development in early to mid-April, despite water quality conditions that allowed for a longer growth period. Though widely distributed, the future of Mesocapnia arizonensis is intimately tied to winter rains, which are forecast to decline under regional climate models.

Michael Bogan (Primary Presenter/Author), School of Natural Resources and the Environment, The University of Arizona, mbogan@email.arizona.edu;


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16:00 - 16:15: / 308 SPATIAL HABITAT DYNAMICS AND POPULATION PERSISTENCE IN INTERMITTENT STREAMS

5/23/2016  |   16:00 - 16:15   |  308

SPATIAL HABITAT DYNAMICS AND POPULATION PERSISTENCE IN INTERMITTENT STREAMS Climate change and human water use pose significant threats to the persistence of aquatic biota in intermittent streams, especially species that depend on permanent aquatic refuges for survival. Here we outline the application of a spatially explicit demographic model to explore interactions between waterhole persistence and fish population viability in an Australian dryland river. The model brings together empirical data on waterhole persistence and future hydrologic scenarios to explore landscape dynamics of habitat persistence and connectivity. We couple this with demographic information derived from repeat field surveys of population structure and dispersal to create a stochastic population model. We modeled plausible future scenarios of climate change and water extraction. Increased local habitat loss greatly increased the risk of population decline, while scenarios of increasing aridity and drought frequency were less detrimental. Our results highlight the importance of spatial connectivity and multiple refuges in maintaining regional population persistence, but also the potential for population variability over the short-term to mask longer-term declines. A landscape perspective is clearly critical to understanding persistence of biota in intermittent streams subjected to increased human disturbances.

Nick Bond (Primary Presenter/Author), La Trobe University, n.bond@latrobe.edu.au;


Stephen Balcombe ( Co-Presenter/Co-Author), Australian Rivers Institute, Griffith University, s.balcombe@griffith.edu.au;


David Crook ( Co-Presenter/Co-Author), La Trobe University, David.Crook@latrobe.edu.au;


Jon Marshall ( Co-Presenter/Co-Author), Department of Science, Information Technology, Innovation and the Arts, jonathan.marshall@dsiti.qld.gov.au;


Jaye Lobegeiger ( Co-Presenter/Co-Author), Department of Science, Information Technology, Innovation and the Arts, j.lobegeiger@dsiti.qld.gov.au;


Norbert Menke ( Co-Presenter/Co-Author), Department of Science, Information Technology, Innovation and the Arts, n.menke@dsiti.qld.gov.au;


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16:15 - 16:30: / 308 FISH LIFE-HISTORY STRATEGIES DEFINE META-POPULATION DYNAMICS IN A DRYLAND STREAM

5/23/2016  |   16:15 - 16:30   |  308

FISH LIFE-HISTORY STRATEGIES DEFINE META-POPULATION DYNAMICS IN A DRYLAND STREAM Dryland rivers are among the most threatened freshwater ecosystems by virtue of significant alterations to the hydrologic regime (dams, land development) and rapidly changing climate leading to more frequent and severe droughts. Fish species with different life history strategies and nativity status (native vs. non-native) are hypothesized to respond differently to future flow conditions, yet empirical evidence exploring this question remains limited. Using the Verde River (Arizona) as a case study, we used spatially explicit patch occupancy models and a hierarchical Bayesian approach to model native and non-native species persistence under the future climate scenarios of increasing drought and loss of hydrologic connectivity. This information theoretic approach accounts for imperfect detection and the spatial effects of dispersal and connectivity to model colonization-extinction dynamics using long-term data sets (1986 – 2013) collected in the Verde basin. Probabilities of species persistence under decreasing water availability varied according to species life-history strategy and nativity, and were used to generalize potential fish responses to changing climate regimes for other intermittent rivers in the western United States.

Jane Rogosch (Primary Presenter/Author), University of Washington, jfencl@uw.edu;


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


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16:30 - 16:45: / 308 TO WHAT EXTENT INVERTEBRATE BIODIVERSITY OF INTERMITTENT STREAMS IN MEDITERRANEAN-CLIMATE REGION IS THREATENED BY CLIMATE CHANGE?

5/23/2016  |   16:30 - 16:45   |  308

TO WHAT EXTENT INVERTEBRATE BIODIVERSITY OF INTERMITTENT STREAMS IN MEDITERRANEAN-CLIMATE REGION IS THREATENED BY CLIMATE CHANGE? Invertebrates inhabiting streams in mediterranean-climate regions (med-rivers) are attuned to relatively short and mild winters followed by hot and dry summers. They are also adjusted to stream hydrology that is influenced by relatively high inter-annual variability in precipitation (high predictability – low constancy). They are therefore naturally exposed to a wide range and variation of environmental conditions, including extreme temperatures, and are expected to be eurythermal. The greatest environmental threat to aquatic ecosystems is drying out, however wetting and dry is the natural hydrologic regime in intermittent streams. Invertebrates inhabiting such ecosystems demonstrate high resistance and resilience to hydrologic variations. Often their community mostly consists of aquatic insects, coping with flooding and drying by timely escaping the site, dispersing to nearby refugia. The rest of the community is mostly represented by invertebrates having dormant stages, resistant to drying. The information on the response of invertebrates in intermittent med-rivers to climate change is mostly circumstantial; it is likely that warming up alone would not have detrimental effect on this community but consecutive drying, will. Refugia are vital for these intermittent ecosystems.

Avital Gasith (Primary Presenter/Author), Tel-Aviv University, avitalg@tauex.tau.ac.il;


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