DOI: 10.5061/dryad.8mv11
title: Data from: Disentangling biotic interactions, environmental filters, and dispersal limitation as drivers of species co-occurrence

description: A key focus in ecology is to search for community assembly rules. Here we
 compare two community modelling frameworks that integrate a combination of
 environmental and spatial data to identify positive and negative species
 associations from presence-absence matrices, and incorporate an additional
 comparison using joint species distribution models (JSDM). The frameworks
 use a dichotomous logic tree that distinguishes dispersal limitation,
 environmental requirements, and interspecific interactions as causes of
 segregated or aggregated species pairs. The first framework is based on a
 classical null model analysis complemented by tests of spatial arrangement
 and environmental characteristics of the sites occupied by the members of
 each species pair (Classic framework). The second framework, (SDM
 framework) implemented here for the first time, builds on the application
 of environmentally-constrained null models (or JSDMs) to partial out the
 influence of the environment, and includes an analysis of the geographical
 configuration of species ranges to account for dispersal effects. We
 applied these approaches to examine plot-level species co-occurrence in
 plant communities sampled along a wide elevation gradient in the Swiss
 Alps. According to the frameworks, the majority of species pairs were
 randomly associated, and most of the non-random positive and negative
 species associations could be attributed to environmental filtering and/or
 dispersal limitation. These patterns were partly detected also with JSDM.
 Biotic interactions were detected more frequently in the SDM framework,
 and by JSDM, than in the Classic framework. All approaches detected
 species aggregation more often than segregation, perhaps reflecting the
 important role of facilitation in stressful high-elevation environments.
 Differences between the frameworks may reflect the explicit incorporation
 of elevational segregation in the SDM framework and the sensitivity of
 JSDM to the environmental data. Nevertheless, all methods have the
 potential to reveal general patterns of species co-occurrence for
 different taxa, spatial scales, and environmental conditions.
description: Environmental data and
 presence-absence information of 175 species in 912 plots in western Swiss
 AlpsThe file contains data
 on 5 environmental predictors (ddeg0=growding degree days with threshold
 of 0 degree, SLOPE=slope angle in degrees, MIND=moisture index as the
 difference between precipitation and evapotranspiration summed over the
 growing season, SOLRAD=summed annual solar radiation, TPI=topographic
 position index describing exposure of exposure of a location in space
 compared to the surrounding terrain) and species presence-absence
 information on 912 plots (4x4m) collected in Swiss western Alps (46°23’ N,
 7°5’ E). Additionally, geographic coordinates of the plots are provided in
 Swiss coordinate system. Subsets and parts of the data have been used in
 other publications of the related research group, ECOSPAT, University of
 Lausanne. For the complete list of publications related to the dataset,
 see https://www.unil.ch/ecospat/home/menuinst/publications.html. In
 addition, "Randin, C. F., et al. (2006). Journal of Biogeography 33:
 10" provides the description of how ddeg0, SLOPE, MIND and SOLRAD
 were derived using meteorological data and 25-m resolution digital
 elevation model (DEM). TPI was calculated from the same 25-m DEM using 3x3
 moving window implementing the method of "Zimmermann, N.E. &
 Roberts, D.W. (2001) Final report of the MLP climate and biophysical
 mapping project. Swiss Federal Research Institute WSL, Birmensdorf,
 Switzerland."Data_Ecospat_Env_PresAbsPlants_912plots.txt