Effects of past and present-day landscape structure on forest soil microorganisms

Principles of landscape ecology have been built on birds and plant species distribution, but the number of clues is now growing on below-ground organisms, whose dispersal may also be affected by above-ground landscape structure. For communities of microorganisms, the question remains if and how they answer to landscape structure, with or without time lag, and if some groups of microorganisms may react more than others. Here, we investigated if fungi or bacteria diversity is driven by the amount of forest cover in the current or the past landscape. We tested the Habitat Amount Hypothesis (HAH) on ancient forests of Cevennes national park, that were particularly fragmented 150 years ago, and are today surrounded by recent forests. As ancient forests are often more diverse in plant species, we hypothesized that the higher quantity of ancient forests in the landscape, the richer fungal and bacterial communities would be locally. More precisely, we expected that ectomycorrhizal fungi, and pa...