DOI: 10.5061/dryad.41ns1rnrx
title: Data from: Habitat heterogeneity overrides local processes to drive the species-area relationship of benthic macroinvertebrates in shallow floodplain lakes

description: The species–area relationship (SAR) on islands describes how the numbers
 of species increase with increasing island size (or island-like habitat,
 such as lakes). Despite its conceptual importance, there is considerable
 uncertainty surrounding its shape in freshwater lakes, as well as the
 potential mechanisms that underlie the SAR. Here, we used
 standardized sampling data of benthic macroinvertebrates
 from 81 shallow lakes in the Yangtze-Huai floodplain
 of China to evaluate its shape and disentangle several
 mechanisms (e.g., passive sampling, colonization-extinction
 dynamics and heterogeneity) underlying the SAR. At the
 whole-lake level, we found an increase in the total species
 richness with increasing lake area, as well as an increase in
 rarefied richness controlling for sampling
 effort. However, within single samples, diversity was
 negatively related to lake area. This scale-dependence is because
 within-lake β-diversity increased with lake area,
 suggesting that heterogeneity overrides local processes to
 generate the positive SAR. These patterns were only
 evident for measures of diversity that equally weigh common and rare
 species (i.e., species richness), and disappeared when diversity measures
 that weigh common species more heavily were used. This
 suggests that the influence of heterogeneity on the
 SAR was largely via its influence on rarer species and
 their turnover in larger lakes. Overall, our result that heterogeneity was
 the primary driver of the positive SAR in this system provides an
 important baseline for making predictions about biodiversity changes with
 ongoing habitat loss.
description: # Habitat heterogeneity overrides local processes to drive the
 species-area relationship of benthic macroinvertebrates in shallow
 floodplain lakes Dataset DOI:
 [10.5061/dryad.41ns1rnrx](10.5061/dryad.41ns1rnrx) ## Description of the
 data and file structure In this study, we used standardized sampling data
 of benthic macroinvertebrates from 81 shallow lakes in the Yangtze-Huai
 floodplain of China to evaluate their shape and disentangle several
 mechanisms (e.g., passive sampling, colonization-extinction dynamics and
 heterogeneity) underlying the SAR. The files contains two kinds of data:
 Macroinvertebrate community (comm_dyrad.csv) and Environment
 (env_dyrad.csv).   The community data showed species density at each
 sampling site of each lake. The unit is individuals per square meter (ind.
 / m2).   The environment data contains:  sampling time, lake name, lake
 location (latitute °N and longnitute °E), lake area (km2), lake mean depth
 (m), total nitrogen (mg/L), total phosphorus (mg/L). ### Files and
 variables #### File: comm\_dyrad.csv **Description:**  ##### Variables *
 date: Sampling date * lake: Lake name * site: Sampling site * sp1 - sp82 :
 density of species 1 to species 82. unit: ind / m2 #### File:
 env\_dyrad.csv **Description:**  ##### Variables * date: Sampling date *
 lake: Lake name * site: Sampling site * latitude: °N * longitute: °E *
 area: Lake surface area (km2) * depth: Lake mean depth (m) * tn: Total
 nitrogen concentration (mg/L) * tp: Total phosphorus concentration (mg/L)
 ## Code/software We used R software for analysis of this work. The
 biodiversity metrics were calculated via "mobr" package. The
 relationship between biodiversity metrics and lake area were analysised
 via "glmmTMB" package.