6/08/2017  |   14:00 - 14:15   |  302B

ASSESSING ANTHROPOGENIC PRESSURES ON STREAM COMMUNITIES: NEW MODELLING APPROACHES BASED ON MACROINVERTEBRATE AND DIATOM ASSEMBLAGES Identifying the anthropogenic pressures impairing ecosystems is a challenging task, especially in streams that integrate multiple pressures (related to water quality, land use and hydromorphology) acting at scales from reach to catchment. Such pressure impacts can be assessed investigating local biotic communities. However, biomonitoring methods such as biological indexes mostly aim at assessing the global impairment magnitude, not the identity and respective importance of involved pressures. Stream organisms are Biological Quality Elements with various combinations of attributes related to mobility, physiology and integration time. This variety allows contrasted responses to different types of pressures. Moreover, habitats act as a templet on which species attributes are selected. In this context, trait combinations can help assessing the ecological impact of specific pressures. We analyzed combinations of taxonomy- and trait-based descriptors of macroinvertebrate and diatom communities using random forest algorithms. Most of these models have demonstrated a good efficiency to identify specific pressure at large spatial scale and on a wide range of environmental conditions. These results represent a further step in stream ecological diagnostic and can support decision-making processes.

Cédric Mondy (Primary Presenter/Author), Interdisciplinary Laboratory of Continental Environments (LIEC), CNRS UMR 7360, University of Lorraine, France, cedric.mondy@gmail.com;


Floriane Larras ( Co-Presenter/Co-Author), Department of Bioanalytical Ecotoxicology, UFZ Helmholtz-Centre for Environmental Research, Leipzig, Germany, floriane.larras@ufz.de;


Philippe Usseglio-Polatera ( Co-Presenter/Co-Author), Interdisciplinary Laboratory of Continental Environments (LIEC), CNRS UMR 7360, University of Lorraine, France, philippe.usseglio-polatera@univ-lorraine.fr;


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6/08/2017  |   14:15 - 14:30   |  302B

TRAIT-BASED DISTURBANCE ANALYSIS: DISPERSAL STRATEGIES AND STREAM COLONIZATION BY AQUATIC MACROINVERTEBRATES Lowland streams are highly dynamic water bodies that are exposed to a variety of environmental stressors. When conditions become unfavourable, aquatic macroinvertebrates disperse to other stretches of stream. The dispersal capacity of macroinvertebrates depends on possession and expression of specific traits. However, it remains unknown which key traits or combination of traits leads to successful dispersal and subsequent colonization of streams by macroinvertebrates. We hypothesize that species 1) do not necessarily use all of their potentially useful traits and 2) traits tend to act in combinations. These hypotheses were tested by monitoring three restored stretches of stream for two years. All dispersed species were identified and compared to the upstream source population to determine which trait combinations lead to successful dispersal and which traits have a negative impact on dispersal capacity. Results show that a combination of feeding strategy, larval locomotion type and number of life cycles per year determines if new habitat is reached and colonized. The outcome of this study will contribute to our knowledge of specific life-history strategies and can improve stream restoration efficiency.

Judith Westveer (Primary Presenter/Author), University of Amsterdam, j.j.westveer@uva.nl;


Piet F.M. Verdonschot ( Co-Presenter/Co-Author), University of Amsterdam / Wageningen Environmental Research , piet.verdonschot@wur.nl;


Harm Van der Geest ( Co-Presenter/Co-Author), University of Amsterdam, Institute for Biodiversity and Ecosystem Dynamics, H.G.vandergeest@uva.nl;


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6/08/2017  |   14:30 - 14:45   |  302B

ECOLOGICAL TRAITS EXPLAIN REGIONAL DISTRIBUTION PATTERNS IN LOWLAND STREAM INVERTEBRATES Large scale degradation of lowland stream ecosystems has resulted in macroinvertebrate diversity loss, but which stressors were ultimately responsible for this decline is often unclear. Using ecological traits we investigated if there were differences in the trait profiles of species groups with a different occurrence pattern in the Campine region, the Netherlands. Macroinvertebrates have been studied here since the beginning of the twentieth century, with routine sampling for bioassessment purposes spanning almost four decades, as well as many observations of adult insects made by volunteer entomologists. Based on this data we reconstructed the regional species pool and assessed the status of each species, being classified as: 1. regionally extinct, 2. no records during the last 10 years, 3. present, but rare, 4. present and common, and 5. cryptic, not in sampling but larvae or adults observed. Trait profiles of these five groups were compared based on their sensitivity to flow intermittency, drought, salinization, organic load, eutrophication and acidification, as well as their substrate and water type preferences. Especially flow related traits appeared to be important predictors.

Ralf C.M. Verdonschot (Primary Presenter/Author), Wageningen Environmental Research, ralf.verdonschot@wur.nl;


Piet F.M. Verdonschot ( Co-Presenter/Co-Author), University of Amsterdam / Wageningen Environmental Research , piet.verdonschot@wur.nl;


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6/08/2017  |   14:45 - 15:00   |  302B

PROGRESS IN USING TRAITS IN CLIMATE CHANGE VULNERABILITY ASSESSMENT Vulnerability assessment is a practical tool supporting development and prioritization of adaptations to climate change, for which the value of integrating the use of species traits has been recognized. Traits are characterized to reflect functional relationships, enabling inference on linkages between trait group patterns and processes potentially driving those patterns. If hypotheses regarding trait responses to climate change effects prove accurate, insights can be derived regarding why vulnerability patterns are observed, and potentially support comparisons across geographic regions that may have differing species pools. Recent traits work show meaningful outcomes using traits can depend on complex considerations. Context and scale may be important; some responses apparent at local (habitat) scales may not be demonstrable at larger (regional) scales. Confounding factors potentially affecting assessment outcomes include intra-specific trait variability, acclimation, and interactions with other stressors. Many traits are inter-correlated (e.g., trait syndromes), potentially leading to miss-interpretation of univariate relationships. And taxa can occupy non-preferred habitats. Simultaneous consideration of multiple traits, quantitative estimation of environmental traits, evaluation of trait diversity/redundancy, and conjunctive methods such as rarity may strengthen the classic traits-based approach.

Anna Hamilton (Primary Presenter/Author), Tetra Tech Center for Ecological Sciences, Anna.Hamilton@tetratech.com;


Britta Bierwagen ( Co-Presenter/Co-Author), US EPA, bierwagen.britta@epa.gov;


Jen Stamp ( Co-Presenter/Co-Author), Tetra Tech, jen.stamp@tetratech.com;


Jonathan Witt ( Co-Presenter/Co-Author), Fairfax County Division of Stormwater Planning, jonathan.witt@fairfaxcounty.gov;


Lei Zheng ( Co-Presenter/Co-Author), previously with Tetra Tech, Inc., lei.zheng@hotmail.com;


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6/08/2017  |   15:00 - 15:15   |  302B

EXPLORING THE ISOTOPIC NICHE OF ROCKY MOUNTAIN-GREAT PLAINS FISH COMMUNITIES Just as the increase in species richness from the poles to the equator is one of the most consistent biogeographical patterns of species distributions, so too is the longitudinal increase in fish species richness from headwaters to lowland rivers. In these ecosystems, we hypothesize that community expansion in fish communities occurs mainly through niche expansion rather than niche packing, whereby the expanded community occupies a large niche space, has low niche overlap among species, and high individual diet specialization. To test this hypothesis, we use carbon (d13C) and nitrogen isotope (d15N) analysis to measure niche widths and individual specialization in fish communities found along the longitudinal gradient in the North Platte River Basin, USA. In this talk, we address the following questions: 1) How is isotopic variability (i.e. niche position and breadth) within local fish communities structured across a river basin, i.e., are species’ niches conserved along the longitudinal gradient? And, 2) how does inter-individual diet variation (i.e. individual specialization) contribute to the isotopic niche breath and overlap of fish communities?

Bryan Maitland (Primary Presenter/Author), University of Wyoming, bmaitlan@uwyo.edu;


Frank Rahel ( Co-Presenter/Co-Author), University of Wyoming, frahel@uwyo.edu;


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6/08/2017  |   15:15 - 15:30   |  302B

THE FUTURE OF TRAIT-BASED APPROACHES IN RESEARCH AND MANAGEMENT The combination of species functional traits provides insight into the environmental conditions to which species have adapted in space and time. These trait combinations are the result of evolutionary adaptations to the prevailing conditions of its habitat. Trait adaptations have phylogenetic constraints, similar to the constraints imposed by the body plan. Thus, species do not necessarily use all of their potential traits, traits will not have equal importance, and traits will always act in combinations. We hypothesise that two major filters decide on the occurrence of a species. First, speciation occurs along the evolutionary time scale. Here major environmental conditions, at the level of water type and within ecoregions, determined, together with phylogenetic constraints, the species’ distribution. Further speciation took place within water bodies, at the habitat scale. Habitat refers e.g., to oxygen, substrate and food. Using a Trichoptera database of >20,000 samples and a Trichoptera trait-database of 69 traits (471 categories) this hypothesis was tested for the Netherlands. Knowledge on the major filters provides the basis to predict future species occurrences and will support both restoration managers and scientists.

Piet F.M. Verdonschot (Primary Presenter/Author), University of Amsterdam / Wageningen Environmental Research , piet.verdonschot@wur.nl;


Ralf C.M. Verdonschot ( Co-Presenter/Co-Author), Wageningen Environmental Research, ralf.verdonschot@wur.nl;


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