DOI: 10.5061/dryad.np5hqbzv6
title: Metapopulation-level associations in positively interacting stream fishes

description: Positive biotic interactions are recognized as important factors
 determining species distributions. Although effects of positive
 interactions have often been observed at local scales, much less is known
 about consequences at larger spatial scales. Here, we study nest
 associations of stream fishes - widespread reproductive facilitation
 between host (nest-builder) and beneficiary (nest associate) species in
 North America - as a model system to examine the role of positive
 interactions in determining the metapopulation-level relationship between
 host and beneficiary species. Using regional data of fish distribution in
 the Midwestern US, we found that watershed-level occupancy of host species
 (i.e., metapopulation occupancy) remarkably increased that of nest
 associates. Our results illustrated that the effects of positive biotic
 interactions at the metapopulation level were comparable or even stronger
 than environmental drivers, i.e., factors that have been studied most
 extensively in metapopulation studies. Further, our model supported the
 hypothesis that the metapopulation-level relationship between hosts and
 nest associates was mediated by a gradient of environmental conditions:
 strong associations occurred under stressful habitats. This study provides
 insightful evidence that positive biotic interactions have larger scale
 consequences for distributions of organisms than previously thought.
 Successful biodiversity conservation may need a broader framework that
 appreciates the role of positive biotic interactions at larger spatial
 scales.
description: 1. Dataset was obtained from five state agencies:
 (1) Iowa Department of Natural Resources (Wilton, 2004)
 (2) Illinois Environmental Protection Agency and Illinois
 Department of Natural Resources (ILEPA, 2014) (3)
 Minnesota Pollution Control Agency (MPCA, 2014) (4)
 Wisconsin Department of Natural Resources (WIDNR, 2018)
 <strong>Note that the raw data are not available due to
 licensing issues.</strong>  
 2. GIS layers adapted from the following materials are licensed
 under: (1)  US National Land Cover Database:
 (https://doi.org/10.5066/P96HHBIE) (2) Climatologies at
 high resolution for the earth’s land surface areas:
 (https://doi.org/10.1038/s41597-020-00587-y) (3) MERIT
 Hydro (high-resolution global hydrography map based on latest topography
 datasets): (https://doi.org/10.1029/2019WR024873)
 (4) Global 1-second water body map version 1.0
 (https://doi.org/10.1016/j.rse.2015.10.014)  
 <strong>References</strong> Wilton, T. F. 2004. Biological assessment of Iowa's wadeable streams. Iowa Department of Natural Resources, Environmental Protection Division, TMDL and Water Quality Assessment Section. Des Moines, Iowa. https://www.iowadnr.gov/Portals/idnr/uploads/watermonitoring/biological/IA_Stream_Bioassessment.pdf ILEPA. 2014. Illinois water monitoring strategy 2015-2020, Illinois Environmental Protection Agency, Bureau of Water, Springfield, Illinois. https://www2.illinois.gov/epa/Documents/epa.state.il.us/water/water-quality/monitoring-strategy/monitoring-strategy-2015-2020.pdf MPCA. 2014. Development of a fish-based index of biological integrity for Minnesota’s rivers and streams. Document number wq-bsm2-03. Minnesota Pollution Control Agency, Environmental Analysis and Outcomes Division, St. Paul, Minnesota. https://www.pca.state.mn.us/sites/default/files/wq-bsm2-03.pdf WIDNR. 2018. Guidelines for assessing fish communities of wadeable streams in Wisconsin version 2.0. Wisconsin Department of Natural Resources. https://www.nemi.gov/methods/method_summary/12960