Forest density and edge effects on soil microbial communities in deciduous forests across Europe
Résumé
Forest fragmentation increases the proportion of edge area and this, in
turn, induces changes in forest structure, species composition and
microclimate. These factors are also strongly determined by the forest
management regime. Although the interactive effects of edges and density
on forest plant communities have been extensively studied, little is
known about the response of the belowground communities. Here we
investigated the variation of soil microbiota in 45 deciduous
broadleaved forests along a latitudinal gradient from Italy to Norway at
a continental scale across Europe. Phospholipid fatty acid (PLFA) and
neutral lipid fatty acid (NLFA) were used to map the microbial community
in the forest edge and interior across three forest densities (dense,
intermediate, open forest). Microbial community composition was only
affected by forest edge effects and not by forest density. We did not
find any interaction effects between forest density and
distance-to-edge. Arbuscular mycorrhizal fungi (AMF) were significantly
more abundant in edges and Gram-negative bacteria more abundant in
interiors, respectively. The microbial community composition was closely
related to soil pH, soil potassium and nitrogen, texture (percent sand)
and soil temperature. Soil pH was positively correlated with the
saprotrophic fungi and potassium was positively correlated with
Gram-negative bacteria but negatively correlated with Actinobacteria. In
sum, we reveal the notable effects of forest edges on the soil AMF
abundance. This result indicated that AMF could possess a stronger
affinity with species growing in the edges, which may help to improve
plant perfor-mance under hostile conditions herein.