Outside Influences

Loss of old-growth forest habitat on a landscape scale
Loss of the majority of low elevation old-growth forest habitat to development and other uses such as short-rotation timber production has greatly reduced the habitat for forest bats. This has likely led to a reduction in forest bat populations from historical levels.

Insecticides and environmental contaminants
Widespread use of insecticides that reduce insect populations may affect bat populations by reducing their prey base. Although bats would not be exposed to pesticides within the watershed, it is possible that migrating individuals could be exposed. Because bats are very long-lived (individuals up to 30 years old have been documented), they have the potential to accumulate toxins that can adversely affect their health and productivity.

Climate change
The effect of global climate change on forest bats and their prey populations is unknown. In the Pacific Northwest, global climate change models indicate that winter and summer temperatures in the region are likely to be warmer. Increased summer temperatures could result in a higher risk of forest fire, which could lead to loss of existing or developing old-growth forest habitat. More information on the status of global climate change can be found on the US Global Change Research Program website.