LE3 .A278 1997

1997

Taylor, Phil

Acadia University

Master of Science

Masters

Biology

Biology

I examine the responses of two species of damselfly, Calopteryx maculata and Calopteryx aequabilis, to differences in landscape structure. I performed surveys to determine patterns of stream occupancy in relation to habitat characteristics measured at small spatial scales, and the medium-scale characteristic of distance to forest. I show that the relative importance of these habitat characteristics differs among species and between survey years. The changes over time are consistent with weather patterns. I then examine the relative abilities of these two species to move through forest and pasture landscapes. Previous work had suggested that C. maculata uses forest as a resource more consistently than C. aequabilis. Results from manipulative experiments show that the connectivity of pasture landscapes is higher than forest landscapes for C. maculata. There was no detectable difference in connectivities for C. aequabilis. These results have implications regarding the relative propensities of individuals to disperse within the structurally different landscapes. I examine the wing morphologies of C. maculata and C. aequabilis individuals collected from landscapes of differing structure. I show that the fore and hindwings of C. maculata individuals are consistent in their asymmetric distributions (left-right) across landscapes. The forewings of C. aequabilis individuals inhabiting a highly fragmented landscape exhibited a significantly higher degree of asymmetry, and were significantly shorter overall, than those inhabiting a moderately fragmented landscape. Forewings of female C. maculata individuals collected from high connectivity (pasture) landscapes were slightly longer than those from low connectivity (forest) landscapes.

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