DOI: 10.5061/dryad.62v6r
title: Data from: Community structure influences species’ abundance along environmental gradients

description: Species response to abiotic environmental variation can be influenced by
 local community structure and interspecific interactions, particularly in
 restricted habitats such as islands and lakes. In temperate lakes, future
 increase in water temperature and runoff of terrestrial (allochthonous)
 dissolved organic carbon (DOC) are predicted to alter community
 composition and the overall ecosystem productivity. However, little is
 known about how the present community structure and abiotic environmental
 variation interact to affect the abundance of native fish populations. We
 used a space-for-time approach to study how local community structure
 interact with lake morphometric and climatic characteristics (i.e.,
 temperature and catchment productivity) to affect brown trout (Salmo
 trutta L.) yield in 283 Norwegian lakes located in different
 biogeographical regions. Brown trout yield (based on data from
 standardized survey gill net fishing; g 100 m−2 gill net night−1) was
 generally lower in lakes where other fish species were present than in
 lakes with brown trout only. It showed an overall negative relationship
 with increasing temperature and a positive relationship with lake
 shoreline complexity. Brown trout yield was also negatively correlated
 with DOC load (measured using Normalized Difference Vegetation Index as a
 proxy) and lake size and depth (measured using terrain slope as a proxy),
 but only in lakes where other fish species were present. The observed
 negative response of brown trout yield to increasing DOC load and
 proportion of the pelagic open-water area is likely due to restricted
 (littoral) niche availability and competitive dominance of more pelagic
 fishes such as Arctic charr (Salvelinus alpinus (L.)). Our study
 highlights that, through competitive interactions, the local community
 structure can influence the response of a species’ abundance to variation
 in abiotic conditions. Changes in biomass and niche use of top predators
 (such as the brown trout), associated with predicted changes in direct and
 indirect climatic factors, may have further influences on the structure
 and function of temperate lake ecosystems.
description: Characteristics of 425
 Norwegian study lakesMorphometric and
 climatic as well as trout yield data (i.e., grams of brown trout per 100
 m2 of survey net per night) from 425 lakes in Norway, Northern Europe.
 "LakeNumber" refers to individual lake numbering by the
 Norwegian Water Resources and Energy Directorate (NVE; www.nve.no). Lake
 morphometry data (area, shoreline development, altitude, coordinates in
 UTM33) is obtained from NVE database. The lake climatic and catchment data
 (mean July air temperature, NDVI = Normalized Difference Vegetation Index,
 and terrain slope) is obtained and measured as described by Finstad et al.
 (2014; DOI: 10.1111/ele.12201). "Stocking" and
 "Regulation" refer to presence/absence of brown trout stocking
 and water level regulation for hydropower, respectively.
 "GillnetSeries" refer to type of gillnet series used for
 catching brown trout, whereas "FishRichness" and
 "FishCommunity" refer to total number of recorded fish species
 and fish community type present in the lake (see the main article for
 description of the latter). The remaining binary data indicates
 presence/absence of different fish species coexisting with brown trout at
 the time of the survey fishing.Norwegian_trout_lakes.csv