Arthropod assemblages on longleaf pines: a possible link between the red-cockaded woodpecker and groundcover vegetation

Little is known about arthropod communities inhabiting longleaf pines in the southeastern United States. This information is of particular importance because arthropods serve as the food base for the federally endangered red-cockaded woodpecker (RCW). In a recent study, this arthropod community has been suggested to be the mechanism by which RCW reproductive success is linked to the groundcover composition of the forest (which is a reflection of the forest's fire history). This is possible because it has been shown that much of the arthropod community found on longleaf pines originates from the forest floor. If the arthropod community is the link between the ground cover and the RCWs' reproductive success then higher amounts of arthropods should be found in areas with groundcover that is indicative of frequent burning. I conducted a one year study at three sites containing RCWs to determine whether the ground cover of the forest influences the abundance and mass of the arthropod communities on longleaf pines. I focused on impacts of groundcover on arthropods by controlling for tree species, tree age, soil type, hardwood midstory density, and overstory basal area. My results show that arthropod biomass was positively and significantly correlated to the percent coverage of herbaceous and graminoid vegetation and was negatively and significantly correlated to the percent coverage of woody vegetation. Arthropod biomass and abundance was also observed to vary seasonally with a peak occurring during spring and summer. Additionally, prescribed fire was not found to have a negative short-term impact on arthropod biomass.