tailieunhanh - Báo cáo lâm nghiệp: " Predator/prey ratios: a measure of bark-beetle population status influenced by stand composition in different French stands after the 1999 storms"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài:" Predator/prey ratios: a measure of bark-beetle population status influenced by stand composition in different French stands after the 1999 storms" | Ann. For. Sci. 63 2006 301- 308 301 INRA EDP Sciences 2006 DOI forest 2006009 Original article Predator prey ratios a measure of bark-beetle population status influenced by stand composition in different French stands after the 1999 storms Nathalie Warzée Marius Gilbert Jean-Claude Grégoire Lutte biologique et Écologie spatiale CP 160 12 Université Libre de Bruxelles 50 av. FD Roosevelt 1050 Bruxelles Belgium Received 25 January 2005 accepted 12 October 2005 Abstract - This study presents the results of a four-year trapping experiment in stands heavily infested by Ips typographus following the 1999 storms in north-eastern France. Ten bottle-traps were stapled on dead spruces or on broad-leaves in five spruce stands among which two comprised pines a species particularly favourable for the pupation of the predator Thanasimus formicarius. The phenology of T. formicarius closely reflected that of its prey in all stands. We show that the proportion of pines within a 500 m radius is the main variable influencing predator prey ratios and that this variable alone outperforms other forest composition indices such as the Shannon diversity index estimated using all tree categories or reduced to integrate only three categories spruce pine others . These results are discussed with regard to the possible role of host trees and host-tree diversity in both insects life-cycles and how the T. formicarius Ips typographus ratios could be used to describe the status of Ips typographus infestations. biodiversity index biological control Ips typographus Scolytidae Shannon index Thanasimus formicarius Cleridae Résumé - Les ratios prédateur proies une mesure des populations de scolytes influencee par la composition du peuplement dans differents sites franẹais après les tempêtes de 1999. Cette étude présente les résultats de quatre années de piégeage dans des peuplements fortement infestés par Ips typographus suite aux tempêtes de 1999 dans le nord-est de la France. Dix .