Effect on disturbance type (fire and harvesting) on the ecological diversity of carabid beetles (Coleoptera: Carabidae) in black spruce (Picea mariana (Mill.) BSP.) forests of eastern Manitoba

Abstract

Disturbance, especially fire, is a crucial part of boreal forest succession, returning the forest to return to an early successional stage. In the boreal forest, fire had been the main disturbance type on the landscape until advances in mechanical harvesting methods allowed for large scale harvesting. At the same time as these advances in harvesting, there has been an increase in fire suppression by active firefighting (Smith et al. 2000). Large-scale harvests are becoming the main disturbance type on the landscape, causing fire-initiated succession to become a threatened process (Kimmins 1997, Niemela 1999). With harvesting now becoming a significant disturbance, forest health must be quantified to determine whether harvesting has the same impact on the forest as fires. Forest health can be assessed using bioindicators. Bioindicators are a group of organisms (that can be from various taxonomic levels) used to represent the diversity patterns of all other organisms in an ecosystem (National Research Council 2000). Choosing the most suitable indicator is based on a combination of the following three criteria: how representative the indicator is of the ecosystem, ease of identification of the indicator, and the time and cost of sampling (Anderson 1999). Carabid beetles (Coleoptera: Carabidae) ecophysiological adaptations (Thiele 1977) and their ability to cope with disturbances in forests make them ideal bioindicators of forest health (Rainio and Niemela 2003). Carabid fauna in several parts of the world, has been investigated in forested systems, including Poland (Fedorenko 1999), Finland (Niemela et al. 1994b), the United Kingdom (Jukes et al.2001), and Canada (Holliday 1991, Niemela et al. 1993)...