title: Rapid Increases in forest understory diversity and productivity following a mountain pine beetle (Dendroctonus ponderosae) outbreak in pine forests.
abstract: The current unprecedented outbreak of mountain pine beetle (Dendroctonus ponderosae) in lodgepole pine (Pinus contorta) forests of western Canada has resulted in a landscape consisting of a mosaic of forest stands at different stages of mortality. Within forest stands, understory communities are the reservoir of the majority of plant species diversity and influence the composition of future forests in response to disturbance. Although changes to stand composition following beetle outbreaks are well documented, information on immediate responses of forest understory plant communities is limited. The objective of this study was to examine the effects of D. ponderosae-induced tree mortality on initial changes in diversity and productivity of understory plant communities. We established a total of 110 1-m2 plots across eleven mature lodgepole pine forests to measure changes in understory diversity and productivity as a function of tree mortality and below ground resource availability across multiple years. Overall, understory community diversity and productivity increased across the gradient of increased tree mortality. Richness of herbaceous perennials increased with tree mortality as well as soil moisture and nutrient levels. In contrast, the diversity of woody perennials did not change across the gradient of tree mortality. Understory vegetation, namely herbaceous perennials, showed an immediate response to improved growing conditions caused by increases in tree mortality. How this increased pulse in understory richness and productivity affects future forest trajectories in a novel system is unknown.
authors: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors: Gregory J
authors: GJ
authors: Pec
authors: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada; Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada.
authors: Justine
authors: J
authors: Karst
authors: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors: Alexandra N
authors: AN
authors: Sywenky
authors: Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada.
authors: Paul W
authors: PW
authors: Cigan
authors: Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada.
authors: Nadir
authors: N
authors: Erbilgin
authors: Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors: Suzanne W
authors: SW
authors: Simard
authors: Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors: James F
authors: JF
authors: Cahill
mesh_terms: D000416:Alberta; D000818:Animals; D044822:Biodiversity; D001517:Coleoptera / Q000472:pathogenicity*; D017753:Ecosystem; D065928:Forests; D028223:Pinus / Q000469:parasitology*; D010935:Plant Diseases / Q000469:parasitology*; D013045:Species Specificity