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Joint species distribution models quantify drivers of aquatic macroinvertebrate assemblage composition
Citation:
Kopp, D., J. Stoddard, Ryan A Hill, J. Doyle, Phil Kaufmann, A. Herlihy, AND Steve Paulsen. Joint species distribution models quantify drivers of aquatic macroinvertebrate assemblage composition. Joint Aquatic Sciences, Grand Rapids, Michigan, May 14 - 20, 2022.
Impact/Purpose:
Benthic macroinvertebrates are important components of biological integrity in aquatic ecosystems. Quantifying how these assemblages respond to environmental factors is often accomplished by aggregating the responses of each taxon. However, this approach neglects biotic interactions and could therefore over- or under-estimate the effects of an environmental variable. We used joint species distribution models to account for biotic interactions and included taxonomic relatedness and traits information to quantify the effect of several environmental gradients on benthic macroinvertebrate assemblages in streams throughout the contiguous U.S. We found these models can sufficiently differentiate between presence and absence locations for most taxa and reveal meaningful insights into environmental factors that could shape aquatic macroinvertebrate assemblages. This study supports the development of novel biological assessment techniques for aquatic ecosystems by demonstrating a relatively new, multivariate extension of single species distribution models with the National Rivers and Streams Assessment dataset.
Description:
Quantifying drivers of biotic assemblage composition is critical for sound ecological assessment. Potential drivers of composition are often evaluated by aggregating taxon-level responses along environmental gradients. Because this approach neglects biotic interactions, the effects of an environmental variable could be over- or under-estimated. Here, we use joint species distribution models (jSDM) to account for biotic interactions and include taxonomic relatedness and traits information to quantify the effect of several environmental gradients on benthic macroinvertebrate assemblages in streams throughout the contiguous U.S. We fit separate jSDMs to nine major ecoregions using data collected by the U.S. Environmental Protection Agency’s National Rivers and Streams Assessment program. We then evaluated how benthic macroinvertebrate assemblages vary along nutrient, salinity, climate, and physical habitat gradients and whether specific traits facilitate or exclude a taxon from a location. We found that jSDMs sufficiently differentiate between presence and absence locations for most genera and that the relative importance of the environmental gradients varies among ecoregions. However, in many ecoregions a relatively large proportion of genera responded to mean summer temperature and substrate diameter. Further, we found evidence that the expression of some traits by a genus is related to how they respond along an environmental gradient. Generally, genus richness increased with increasing mean substrate diameter but declined with increasing total phosphorous and sulfate concentrations. Our results showcase a new approach to modeling biotic assemblages in aquatic ecosystems and provide insights into how they might change under anthropogenic disturbances.