Rocky Mountain bark beetle infestation

rdf:langString Rocky Mountain bark beetle infestation

rdf:langString The current bark beetle infestation in the Rocky Mountain region of the United States was first detected in 1996. It involved the Mountain pine beetle, which has since spread across millions of acres of dense forest land. In addition, Spruce beetle populations have also been growing in the area in recent years and are further contributing to the existing outbreak. One of the main factors limiting bark beetle population growth is the temperature they can survive at and climate change has raised the average temperature in the region resulting in warmer winters and hotter, drier summers. This not only sped up the bark beetle reproduction process by providing more time per year for them to complete their developmental stages (at lower elevations they now often complete generations in one year instead of two), moisture stressing due to hotter temperatures also weakens the trees’ defense against attacks by reducing resin production. Furthermore, forest management has also played a significant role as many forests in the region have very dense tree populations which facilitates faster spreading from tree to tree, as well as weakening tree defenses further by stressing them through excessive competition. While the culling of the region's trees brings significant economic ramifications, ecosystems are also being profoundly impacted: affected watersheds are experiencing changes to storage and flow, and such high rates of tree mortality alters the exchange of gases between the biosphere and atmosphere. Forest disturbances such as fires usually have nebulous and far-ranging ecological impacts, and bark beetle infestations are no exception. Though many species are benefiting from the infestation and are showing higher rates of occurrence in affected forests, many show the opposite effect. Most notably, elk are avoiding beetle-killed forests even though they traditionally adapt well to many disturbances and capitalize on them, representing significant decrease in elk habitat. The loss of transpiration from beetle-killed trees has also increase groundwater contributions to affected watersheds, which may affect riverine ecosystems, as well as human water usage, by altering factors like water supply and quality. Finally, though forests act as carbon sinks that absorb atmospheric carbon, the high rate of tree mortality not only reduces forests’ capacity to absorb carbon, the large amounts of carbon already stored in beetle-killed trees is being released back into the atmosphere as they decompose.