Ecological Impacts of Southern Pine BeetleThis article is part of a larger document. View the larger document here.
The southern pine beetle (SPB) is the most important biotic disturbance in southern pine forests and causes extensive changes to the forest environment. In this chapter we provide an overview of the ecological impacts of the SPB on forest conditions (the state of the forest) and on forest resources (uses and values associated with the forest). We define ecological impact as the effects—positive or negative—of SPB activities on the forest ecosystem. The impact on forest conditions is the result of widespread tree mortality, which affects ecological processes such as: primary production, nutrient cycling, forest succession, and forest composition and configuration. We discuss how the SPB affects these ecological processes through modification of the physical environment and the temporal distribution of resources. For the ecological impact on forest resources, we emphasize the impacts of SPB on resources that are affected from an ecological point of view (e.g., hydrology and wildlife). Changes in forest structure resulting from SPB herbivory can modify key hydrologic processes that control the quantity and quality of water reaching a stream. The ecological impacts of the SPB on wildlife are the result of changes in the distribution and abundance of plant species and insect populations. Increases in SPB densities directly affect the food available for insectivore birds, mainly bark-foraging woodpeckers. The impacts on wildlife have been deduced from changes in wildlife habitat as a result of SPB infestations. An approach to estimate the impacts of SPB herbivory on wildlife habitat in a forest landscape is introduced.