Plant response to habitat amount and configuration in Swedish forests

Aim: There is an intense debate about whether habitat fragmentation has a negative or positive effect on biodiversity. We examined whether species richness and
incidence of forest plants were negatively or positively associated with fragmented forest configuration. We also analysed whether the results support the fragmentation
threshold hypothesis with fragmentation effects only in landscapes with small habitat amount.
Location: Södermanland province, south-eastern Sweden (8,388 km2).
Methods: Data consisted of plant distribution maps and landscape data on forest amount and configuration in 2.5 km × 2.5 km quadrats. We carried out models including
forest area together with clumpiness index (CL models) or edge density (ED models) as the measure of habitat configuration. We focused on plant taxa with positive association between incidence and forest area (163 taxa in CL models; 119 taxa in ED models).
Results: Responses to fragmented configuration were negative more often than by ra...