title: The birch tube-maker Acrobasis betulella in a fragmented habitat: the importance of patch isolation and edges.
abstract: We examined the response of the birch tube-maker Acrobasis betulella Hulst (Lepidoptera: Pyralidae) to habitat patch isolation and edges. Density of A.␣betulella larva was higher on distant islands than on islands close to the shore. Following experimental removal of all larvae from the islands, adults were able to recolonize even the most distant islands, and larval density was again positively correlated with the degree of isolation. Larval density was not correlated with island size or the amount of birch present on the islands. Larvae on more distant islands did not have lower mortality than those in less isolated sites. Larvae were found more often on edges than in the interior of birch stands and developed faster on edges. This positive edge effect, coupled with the ability of the adults to disperse to even our most distant islands, suggests that A. betulella would be favored in an environment fragmented at the same scale as our island system.
authors.affiliation: Groupe de recherche en écologie forestière, Université du Québec à Montréal, CP 8888, succ. Centre-ville, Montréal, Québec, H3C 3P8, Canada, , , , , , CA.
authors.forename: N
authors.initials: N
authors.lastname: Cappuccino
authors.affiliation: Groupe de recherche en écologie forestière, Université du Québec à Montréal, CP 8888, succ. Centre-ville, Montréal, Québec, H3C 3P8, Canada, , , , , , CA.
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Martin
keywords: Key words Colonization ;   Habitat fragmentation ;  Acrobasis betulella;  Dispersal ;  Edge effects 