Abstract
Some sites in Southern Sweden hold a high proportion of temperate deciduous trees, e.g. oak and beech, which host many red-listed species. It is suggested that the hotspots are too few and fragmented for these species to survive in the long run – that there is a so called ‘extinction debt’. The empirical evidences for the existence of an extinction debt are however weak, probably because data of the long term historical occurrence of threatened species are scarce. In this project we will study two temperate deciduous forest hotspots in southern Sweden, and the surrounding ‘normal production forest’ (the matrix). We will combine fossil beetle analysis with pollen analysis to get data both on the historical beetle populations and on the historical forest composition. A pilot study from one of the hotspots, Siggaboda, gives an indication of the potential of the palaeoentomological technique. In a single core covering the last 1000 years, as much as 23 red-listed wood-dependant beetle species were found. Of these, no fewer than 16 are now extinct from the area. We will test the following hypotheses: 1. The forest and beetle composition was similar in the matrix and in the hotspots before large scale anthropogenic induced changes began 200-500 years ago. 2. The hotspots, although still diverse compared to the matrix, have experienced a continued species loss for many years, i.e. indication of the existence of an extinction debt.
Sweden