Joint species distribution models reveal taxon-specific sensitivities to potential anthropogenic alteration

Taxon-environment relationships elucidate a taxon’s tolerances and preferences for specific environmental conditions. We use a joint species distribution modeling framework, Hierarchical Modeling of Species Communities, to quantify relationships between approximately 1,700 benthic macroinvertebrate assemblages across the contiguous United States and several environmental gradients that are susceptible to human alteration. We then compared how these relationships varied among nine large ecoregions. We found that the models adequately explain the probability of occurrence for most genera (Median Tjur R2 = 0.15-0.24) and a relatively large percentage of genera (32-58%) had positive or negative relationships with the environmental gradients. We detected relatively few unimodal genus-environment relationships. We also investigated whether a suite of traits is related to a genus’ response to an environmental gradient. Our results indicate that a single trait can be positively related to an organism’s occurrence along one environmental gradient but negatively related to its occurrence along another. For example, thermal preference was positively related to mean summer air temperature but negatively related to nutrient concentrations in several ecoregions. At the assemblage level, genus richness was typically lower in the presence of elevated anthropogenic impacts for all ecoregions. Collectively, our results showcase a new approach for modeling biotic assemblages in aquatic ecosystems that can assist in the interpretation and prediction of ecological change.

Impact/Purpose

Quantifying taxon-specific tolerances or sensitivities to anthropogenic activities can assist in the interpretation and prediction of ecological change. Benthic macroinvertebrates are important components of biological integrity in aquatic ecosystems but efforts to quantify how these taxa respond to changes in environmental conditions often exclude rare taxa to avoid statistical overfitting and do not use information that about which taxa co-occur with one another to improve predictions. We overcome these challenges using a relatively new joint species distribution modeling framework to quantify how macroinvertebrate assemblages respond to environmental gradients that are commonly altered by anthropogenic activities and how taxonomic relatedness and traits influences these responses. We found that a relatively large percentage of genera (32-58%) had either positive or negative relationships with the environmental gradients and that a single trait can be positively related to an organism's occurrence along one environmental gradient but negatively related to its occurrence along another. Collectively, our results showcase a new approach for modeling biotic assemblages that can elucidate taxon-specific sensitivities and tolerances to human alterations.

Citation

Kopp, D., J. Stoddard, R. Hill, J. Doyle, P. Kaufmann, A. Herlihy, AND S. Paulsen. Joint species distribution models reveal taxon-specific sensitivities to potential anthropogenic alteration. The Society for Freshwater Science, Springfield, IL, 42(3):215-336, (2023). [DOI: 10.1086/726283]

DOI: Joint species distribution models reveal taxon-specific sensitivities to potential anthropogenic alteration