Reduced ground beetle activity following ice damage in maple stands of southwestern Quebec

The 1998 ice storm led to significant tree crown loss in the deciduous forests of southwestern Quebec. Increased irradiation in the understory may alter edaphic parameters of affected forests, such as temperature and humidity. We examined effects such a disturbance might have on the epigeal fauna of sugar maple stands during the summers of 1998 and 1999. Dry pitfall traps were set in the deciduous forest of Mont-Saint-Bruno Provincial Park, 20 km southeast of Montreal, Quebec under three different post-ice storm conditions (light tree crown loss, severe loss, and gaps) from mid-July to mid-August. We captured significantly fewer total Coleoptera and Carabidae at sites damaged by the ice storm. Species diversity of Coleoptera was also lower at damaged sites. However, the daily activity cycle of the insects did not change following heavy crown loss. Synuchus impunctatus (Say), the dominant forest species, proved to be very sensitive to the disturbance, Observed decreases in insect abundance may be related to environmental changes resulting from heavy crown loss; these effects were probably both direct (on metabolism) and indirect (on nutritional resources).