Session Information
| Session | Poster Session | | Date | Monday (2008-04-07) | | Time | 5:00 PM - 7:00 PM | | Room | Grand Terrace |
Presentation Information
| Presenter | Vanessa Quinn | | Title | Landscape factors influence population connectivity in the forest insect Choristoneura fumiferana | | Affiliation | Purdue University North Central | | Authors | Vanessa Quinn, Gladys Andino, Dean Anderson, Brian Sturtevant | | Keywords | AFLP, Balsam fir, Population connectivity, Spruce budworm | | Presentation Type | Poster | Abstract:
Insects are a major agent of forest disturbance and affect an estimated 50 million acres of forest habitat in the United States. One such important pest in spruce and balsam fir forests throughout boreal and sub-boreal systems of North America is the eastern spruce budworm (Choristoneura fumiferana). This insect exhibits an outbreak pattern thought to be regionally synchronized. However, aerial surveys beginning in the 1950s and continuing to the present suggest that a repeated, expanding and contracting pattern of defoliation shifts to different zones of the landscape. It is unclear how, or if, population connectivity of spruce budworm is related to this outbreak pattern. Although dispersal distances in this insect average 80-km the affect of landscape factors on dispersal and population connectivity has not been addressed. To examine the effect of host plant distribution on spruce budworm population connectivity we analyzed amplified fragment length polymorphisms in three different landscape types in an experimental landscape within a 2-million ha Laurentian mixed forest ecoregion along the U.S.-Canadian border of Minnesota and Ontario. The first landscape type occurs in Minnesota where forest harvest regimes include a fine-scale cutting unit that averages about 14-ha. In contrast, harvest units in Ontario are an order of magnitude larger. Between these two regions lies a 1-million ha unmanaged wilderness area. Therefore, we can evaluate the effect of host plant distribution on the spruce budworm population connectivity. To investigate the influence of insect dispersal and population connectivity on the outbreak dynamics we used amplified fragment length polymorphisms from twelve primer pairs. We analyzed data from 140 individuals from seven different sampling locations. Three hypothetical populations exist from individuals in the seven sampling sites. Our data indicate that spruce budworm dispersal may contribute to the spatial pattern of forest disturbance. |
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