Research article - Peer-reviewed, 2022
Interactive effects of drought and edge exposure on old-growth forest understory speciesKoelemeijer, Irena A.; Ehrlen, Johan; Jonsson, Mari; De Frenne, Pieter; Berg, Peter; Andersson, Jenny; Weibull, Henrik; Hylander, Kristoffer
AbstractContext Both climatic extremes and land-use change constitute severe threats to biodiversity, but their interactive effects remain poorly understood. In forest ecosystems, the effects of climatic extremes can be exacerbated at forest edges. Objectives We explored the hypothesis that an extreme summer drought reduced the richness and coverage of old-growth forest species, particularly in forest patches with high edge exposure. Methods Using a high-resolution spatially explicit precipitation dataset, we could detect variability in drought intensity during the summer drought of 2018. We selected 60 old-growth boreal forest patches in central Sweden that differed in their level of drought intensity and amount of edge exposure. The year after the drought, we surveyed red-listed and old-growth forest indicator species of vascular plants, lichens and bryophytes. We assessed if species richness, composition, and coverage were related to drought intensity, edge exposure, and their interaction. Results Species richness was negatively related to drought intensity in forest patches with a high edge exposure, but not in patches with less edge exposure. Patterns differed among organism groups and were strongest for cyanolichens, epiphytes associated with high-pH bark, and species occurring on convex substrates such as trees and logs. Conclusions Our results show that the effects of an extreme climatic event on forest species can vary strongly across a landscape. Edge exposed old-growth forest patches are more at risk under extreme climatic events than those in continuous forests. This suggest that maintaining buffer zones around forest patches with high conservation values should be an important conservation measure.
KeywordsEdge effects; Extreme weather; Fragmentation; Land-use; Microclimate; Woodland key habitats
Published inLandscape Ecology
2022, volume: 37, number: 7, pages: 1839-1853
Koelemeijer, Irena A.
Swedish University of Agricultural Sciences, Swedish Species Information Centre
De Frenne, Pieter
Swedish Meteorological and Hydrological Institute
Sustainable Development Goals
SDG15 Life on land
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