Evaluating the Impact of Invasive Species in Forest Landscapes: the Southern Pine Beetle and the Hemlock Woolly Adelgid
The southern pine beetle, Dendroctonus frontalis (Zimmerman) (Coleoptera: Curculionidae: Scolytinae) (SPB) is an indigenous invasive species that infests and causes mortality to pines (Pinus spp.) throughout the Southern United States. The hemlock woolly adelgid, Adelges tsugae (Annand) (Homoptera: Adelgidae) (HWA), is a nonindigenous invasive species that infests and causes mortality to Eastern hemlock (Tsuga canadensis) and Carolina hemlock (T. caroliniana) throughout their range in Eastern North America. Both of these insect species occur in the Southern Appalachians, and both have recently caused tree mortality exceeding historical records. Herbivory by both species is of concern to forest managers, but for different reasons. In the case of the SPB, emphasis centers on forest restoration strategies, and in the case of the HWA, the concern is on predicting the impact of removing hemlock from the forest environment. Both of these issues can be investigated using a landscape simulation modeling approach. LANDIS is a simulation modeling environment developed to predict forest landscape change over time. It is a spatially explicit, landscape-scale ecological simulation model that incorporates disturbance by fire, wind, biological disturbance (insects and pathogens) and harvesting. Herein, we present a case study using LANDIS to evaluate the impact of herbivory by the SPB and HWA on forest landscapes in the Southern Appalachians.
- Introduction : In 2003, 5 general areas were identified as concerns to healthy forests in the United States—wildfires, non-native invasive insects and pathogens, invasive plant species, outbreaks of native insects, and changing ecological processes.
- Background : SPB and HWA are two very different forest-damaging insects that inhabit host tree species, which exploit opposite ends of the moisture gradient found in the Southern Appalachian Mountains, although they occasionally occur together at either end of their natural range.
- Methods : This section describes the study area, model, and simulation methods.
- Results and Discussion : Southern Pine Beetle and Hemlock Woolly Adelgid study results are summarized and discussed in the following sections.
- Directions for Future Research : Recently, LANDIS II has been released.
Encyclopedia ID: p3313
