At which spatial and temporal scales does landscape context affect local density of Red Data Book and Indicator species?

Abstract

The landscape context is crucial for forest conservation in regions where the natural forest is fragmented. The focus of practical conservation is currently shifting from local stands to a landscape perspective, but few studies have tested the relative effect of different spatial and temporal scales for occurrence and persistence of species of conservation concern. We studied Red Data Book and Indicator species (the latter proposed to indicate presence of Red Data Book species) of vascular plants, lichens, bryophytes and wood-inhabiting fungi in 22 old temperate broadleaved forests in southern Sweden. We analysed at which scales these species respond to habitat proportion in surrounding landscape. The proportion of suitable habitat was measured at two temporal scales (present-day and historic) and at two spatial scales (about 0–1 km and 1–5 km of study sites). Local density of Red Data Book species increased with increasing proportion of suitable habitat in the current landscape (within 1–5 km of study sites) while Indicator species were unaffected. The response to landscape differed between organism groups. Vascular plants (near significantly) and wood-inhabiting fungi showed a time delay of 120 years in their response, indicating a possible regional extinction debt. An appropriate minimum landscape scale for conservation of Red Data Book species in temperate broadleaved forests in Sweden seems to be about 5 km (radius), but smaller landscapes may be important for vascular plants and wood-inhabiting fungi of conservation concern. In addition, restoration is urgent to counteract the effect of time delays in species responses to recent habitat loss.