Pennsylvania’s white-tailed deer populations have experienced considerable shifts in abundance over the past centuries, due to the combination of exploitation (e.g., hunting) followed by protections (e.g., establishment of game lands, relocation efforts). Currently, populations are estimated to be 3x the density (30 deer per square mile) of pre-industrial settlement (8 to 10 deer per square mile) [1]. The effects of ungulate herbivory on vegetation dynamics have been studied extensively, but studies are less prevalent on how ungulates affect below-ground processes [2]. One area that deserves specific attention is the effect of deer herbivory on soil microbial processes. Herbivores can increase or decrease spatial patchiness of vegetation [3], which in turn controls patchiness of soil conditions [4]. Changes in the spatial configuration and patchiness of soil properties could alter the balances between microbial processes such as methane oxidation and methanogenesis, and coupled nitrification-denitrification, altering ecosystem-level fluxes of greenhouse gases.

Our pilot study uses two 24-year-old deer exclosures on Lacawac Sanctuary, in Wayne County. Changes in vegetation structure and small mammal populations have been documented at these sites. We seek to understand whether spatial patchiness of soil conditions differs inside and outside these exclosures and whether any differences are predictive of methane and nitrous oxide (production at the stand level.