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Understanding connectivity among populations in fragmented landscapes is of paramount importance in species conservation because it determines their long-term viability and helps to identify and prioritize populations to conserve. Rare and sedentary species are particularly vulnerable to habitat fragmentation as they occupy narrow niches or restricted habitat ranges. Here, we assess contemporary interpopulation connectedness of the threatened, myrmecophilous butterfly, Maculinea alcon, in a highly fragmented landscape. We inferred dispersal, effective population sizes, genetic diversity and structure based on 14 locations of M. alcon in Belgium and the Netherlands using data from 12 microsatellite loci. Despite the reported sedentary behaviour of M. alcon, we observed moderate levels of contemporary dispersal between patches, but only in landscapes where populations were located within a distance of 3 km from neighbouring populations. Estimates of effective population sizes (Ne) were very low(ranging from1.6 to 17.6) and bottleneck events occurred in most of the studied populations. We discuss the functional conservation units delineated based on a former mark-release-recapture study, and formulate appropriate conservation strategies to maintain viable (meta)populations in highly fragmented, anthropogenic landscapes.

Red Lists are used to assess the extinction risk of species based on quantitative IUCN criteria. For the compilation of a new Red List of butterflies in Flanders (north Belgium), we collated ca 800,000 distribution records and applied the IUCN Red List criteria to this small region (ca 135,00 km2). We also explored the effect of spatial resolution on the outcome of the Red List assessment by alternatively using 1 × 1 km2 and 5 × 5 km2 grid cells for geographic range size and trend calculations. We determined conservation hot spots in Flanders based on the Red List status of the species composition in each grid cell. The new Red List classified 20 butterflies (out of 68 resident species) as Regionally Extinct, six as Critically Endangered, five as Endangered, seven as Vulnerable and seven as Near Threatened. The remaining 23 species were classified as Least Concern. Using coarse instead of fine grain grid cells would have classified ten species in a lower Red List category. Compared with the previous Red List, nine species were classified in a lower and 12 in a higher threat category. In total, 218 1 × 1 km2 grid cells were considered as (very) high butterfly conservation priority sites. The application of the new IUCN criteria in a small region such as Flanders resulted in a Red List that offered challenging opportunities for the conservation of butterflies in particular and biodiversity in general.

Twenty years ago, Desender and Turin (1989) analysed the changes in the composition of carabid beetles in four NW European countries between the periods

ABSTR AC T Woodpastures (open, grazed woodlands with a mosaic of grassland, shrub and tree patches) are of high biological and cultural value and have become a threatened ecosystem in Europe. Spontaneous tree regeneration in the presence of large herbivores, is an essential process for management and restoration of this structurally diverse habitat. We examined the suitability of five vegetation types (grasslands, ruderal vegetations, tall sedges, rush tussocks and bramble thickets), grazed by large herbivores, for tree regeneration. We hypothesized that bramble thickets and tall herb communities operate as safe sites for palatable tree species through the mechanism of associational resistance. We set up a field experiment with tree seedlings in grazed and ungrazed conditions and recorded mortality and growth of seedlings of two palatable tree species (Quercus robur and Fraxinus excelsior) during three growing seasons. In the same experiment, we studied the effect of a two year’s initial time gap before grazing. Bramble thickets were suitable safe sites for survival and growth of seedlings of both species. Tall sedges, soft rush tussocks and ruderal vegetations with unpalatable or spiny species provided temporal protection, allowing seedlings to survive. Tree regeneration in livestock grazed grassland was highly constrained. Rabbits may undo the nursing effects of bramble thickets. The first year’s survival is of major importance for the establishment of trees. Subsequent grazing affects growth rather than survival. A two year’s initial time gap before grazing, had positive effects on survival, but did not enhance outgrowth of unprotected trees.

We illustrate the strong decrease in the number of butterfly species in Flanders (north Belgium) in the 20th century using data from a national butterfly mapping scheme. Nineteen of the 64 indigenous species went extinct and half of the remaining species are threatened at present. Flanders is shown to be the region with the highest number of extinct butterflies in Europe. More intensive agriculture practices and expansion of house and road building increased the extinction rate more than eightfold in the second half of the 20th century. The number of hot spots decreased considerably and the present-day hot spots are almost exclusively in the northeast of Flanders. Species with low dispersal capacities and species from oligotrophic habitats decreased significantly more than mobile species or species from eutrophic habitats. We discuss these results in a northwest European context and focus on concrete measures to preserve threatened butterfly populations in Flanders.