The impact of pinyon mortality on ground-dwelling arthropod communities

Abstract

We documented the indirect impact of drought-induced mortality of pinyon pine (Pinus edulis) on ground-dwelling arthropod communities. Tree mortality alters microhabitats utilized by ground-dwelling arthropods through increased solar radiation, dead woody debris, and understory vegetation. Our major objectives were to determine if there were differences in species composition, richness and abundance of ground dwelling-arthropods associated with environments experiencing high or low pinyon mortality and whether specific microhabitats could account for differences. We predicted significant impacts on arthropod community dynamics due to the increased complexity of micro-habitats from both standing and fallen trees. Despite only moderate increases in the amount of area that experienced new microhabitats, there were significant differences in arthropod community composition between high and low pinyon mortality environments. Overall, 22% (51 taxa) of the arthropod community were identified as being indicators of high or low pinyon mortality. Thus, our study supported the notion that arthropods are responsive to disturbance events that lead to even moderate changes in the environment. However, areas of high tree mortality also contained lower tree densities, allowing for the possibility that intrinsic differences in woodlands that vary in susceptibility to drought-induced mortality plays a significant role in structuring ground-dwelling arthropod communities.

Citation

Delph, Robert J. 2008. The impact of pinyon mortality on ground-dwelling arthropod communities. Flagstaff, AZ: Northern Arizona University. 56 p. Thesis