HISTORICAL LANDSCAPE CONNECTIVITY AFFECTS PRESENT PLANT SPECIES DIVERSITY

Abstract

Transformation of landscapes is considered to be one of the main drivers behind species loss, regionally and globally. Theory and empirical studies suggest that landscape structure influences species diversity in many habitats. These effects may be manifested at different spatial scales depending on species response to landscape heterogeneity. A similar, but often neglected, scaling issue concerns the temporal scale of species response to landscape change. In this study, we found time lags of 50–100 years in the response of plant species diversity to changing configuration of habitats in the landscape. When analyzing remnants of traditionally managed seminatural grasslands in Sweden, we found that species diversity was not related to present-day connectivity of the investigated sites, irrespective of spatial scale (3.1–12.5 km2). However, when using maps depicting landscapes 50 and 100 years ago, respectively, strong positive effects of habitat connectivity appeared, at increasing spatial scale for the older landscapes. Thus, analyses of how species diversity relates to present-day landscapes may be misleading, and future species loss may be expected even if the present landscape is maintained.