Changes in the distribution of carabid beetles in Belgium revisited: Have we halted the diversity loss?

Twenty years ago, Desender and Turin (1989) analysed the changes in the composition of carabid beetles in four NW European countries between the periods <1950 and 1950-1985. Recently, a new distribution atlas of carabid beetles in Belgium was compiled using data collected during the period 1986-2008. In the light of the Countdown2010 target of halting the loss of biodiversity, we used these new data to test whether or not previously observed trends were altered. Since 1950, 46 species were no longer recorded in Belgium and seven species were added to the Belgian fauna. By relating the changes in distribution area to ecological and life history traits as well as to conservation priorities of the species, we examined which species characteristics were associated with the strongest changes in distribution. Comparing the period before 1950 with the period 1950-1985 showed that species from nutrient-poor dry biotopes and heathlands, threatened, rare and big species declined. Generalists, non-threatened species, species with a pan-European distribution range, species in the centre of their distribution range and common species, on the other hand, increased. From the period 1950-1985 to 1986-2008, mainly macropterous species, both rare and very common species and big species decreased, while generalists, dimorphic species, species with a pan-European distribution range and species that were already common in the second period increased. For the conservation of carabid beetles in a strongly industrialised and highly fragmented NW European landscape, we propose actions on two levels: first, the protection and adequate management of high quality biotopes, especially nutrient-poor grasslands and heathlands, in large core areas for specialist species and second, the creation and/or restoration of a ‘matrix’ that facilitates the exchange of individuals between core areas for the conservation of both generalist and specialist species.     

A culture filtrate of Phytophthora infestans primes defense reaction in potato cell suspensions

Priming of defense reactions by an elicitor results in an enhanced ability of the plant to respond to subsequent pathogen challenges. We previously showed that application of lipopolysaccharides (LPS) to potato cell suspensions causes apoplastic acidification, but does not stimulate lipoxygenase (LOX) activity. Here, we tested the ability of various elicitors to prime and elicit defense reactions in potato cell suspensions. Adding 20 microg ml(1) LPS, laminarin, harpin N, or a concentrated culture filtrate (CCF) of Phytophthora infestans to cell cultures 18 h before a second elicitation with LPS did not alter the intensity of apoplastic acidification compared with a single LPS application. Conversely, high concentrations (200 or 400 microg ml(1)) of LPS, laminarin, and harpin N activated LOX in cells pretreated with 1 microg ml(1) CCF, but not in cells pretreated with LPS, laminarin, or harpin N. LOX response was maximal in pretreated cells of potato cv. Bintje when the second elicitation occurred 18 to 24 h after CCF application. These results showed that LOX activation is primed in potato cells by CCF, but not by LPS, harpin N, or laminarin. Finally, bioassays showed a slightly greater reduction of rot weight in half tubers treated with CCF followed by LPS before inoculation with Pectobacterium atrosepticum than in half tubers treated with either preparation alone, indicating a priming effect of CCF on both LOX induction and disease suppression.