Disturbance disrupts the relation between community similarity and environmental distance at small spatial scale

DÍAZ VILLANUEVA, VERÓNICA; MARILUAN, GUSTAVO; ALBARIÑO, RICARDO

ECOLOGICAL RESEARCH

SPRINGER TOKYO

Año: 2017 vol. 33 p. 225 - 236

0912-3814

Aquatic invertebrate distribution within a flu-vial network is affected both by dispersal capabilities ofthe species and changes in the environment along spatialgradients. Disturbance that affects part of the networkmay represent an abrupt change in environmental gra-dients, which should be reflected on its communities. Weanalysed whether the composition of benthic insectcommunities is associated to environmental and geo-graphic distances in a small catchment, partially dis-turbed by a wildfire (non burned forest-control: C,moderate impacted: I and burned zones: B). We postu-lated that changes in main resource availability differ-ently affect certain functional feeding groups. We foundthat taxonomic differences were related to the distur-bance condition but not to the distance among streamsand that the effect of disturbance targeted mostly onshredders. Environmental differences were larger amongC sites than among B sites, but community taxonomiccomposition was more similar among C than B sites. Asa result, neither environmental nor geographic distancesexplained community similarity. When the analysis wasscaled up by incorporating new data from a larger area,community similarity was explained both by environ-mental and geographic distance, independently (i.e.geographic and environmental distances did not corre-late). Our results highlight the influence of a disturbanceon the riparian vegetation on the benthic communitycomposition and functional structure of forestedstreams, and showed the effect of scale in habitat asso-ciation, as environmental and geographic distance to-gether explained community similarity when the spatialscale was enlarged.