Spatial dynamics of the invasive defoliator amber-marked birch leafminer across the Anchorage landscape.

The amber-marked birch leafminer (Profenusa thomsoni [Konow]) (Hymenoptera: Tenthredinidae) has caused severe infestations of birch species in Anchorage, AK, since 2002. Its spatial distribution has been monitored since 2006 and summarized using interpolated surfaces based on simple kriging. Results indicate that this insect pest is unevenly distributed, occurring in multineighborhood sized patches that migrate from year to year. Patches showing heavy infestation one year are followed by light infestations the following year. In this study, we developed methods of assessing and describing spatial distributions of P. thomsoni as they vary from year to year, and speculate on potential causes of these trends in landscape patterns.