Impacts of wild pigs on acorn availability as a food source for native wildlife

Abstract

Context. Wild pigs (Sus scrofa) are a non-native invasive species that causes millions of dollars in damage each year to agriculture in the United States of America, destroys native plant communities, and competes with native wildlife for seasonally available pulse resources such as acorns. Despite many anecdotal observations and diet studies suggesting wild pigs reduce acorn availability for other wildlife species, no studies have comparatively examined acorn consumption among species in a natural environment (i.e. competition). Aims. Our objective was to estimate the consumption of acorns by wild pigs relative to that of other native wildlife species. Methods. We established 40 monitoring stations beneath acorn-producing trees in a 3406-ha study area in eastern Alabama with an approximate density of 9 pigs/km 2 . At each monitoring station, we placed five acorns on a 1-m × 1-m sand pad and positioned a game camera to record acorn fate during 2-week intervals once a month from September to February 2018-2019 and 2019-2020. Cameras were set to capture images once every minute continuously during the survey period. Additionally, we constructed acorn traps from 18.9-L plastic buckets to estimate the timing and relative amounts of acorns that were potentially available for consumption at each monitoring station. Key results. From approximately 7.3 million camera images, we observed 15 wildlife species consuming 707 acorns over the 2 years. Aside from animal consumption, acorn fate was categorised as lost due to flooding (n = 153), remaining on the sand pad at time of camera failure (n = 720), or not consumed during the sampling period (n = 536). Key conclusions. Top acorn consumers were squirrel (Sciurus spp.), white-tailed deer (Odocoileus virginianus), raccoon (Procyon lotor), and wild pig. In the 2018-2019 sampling period, wild pigs consumption accounted for 23.4% (n = 87) of the total consumed acorns. After wild pig removal efforts were initiated in the summer and autumn of 2019, wild pigs consumed only 7.2% (n = 24) of consumed acorns. Implications. Wild pigs consume a significant number of acorns and likely reduce the availability of this pulse resource for other native wildlife species and may potentially influence oak regeneration.

Anthropogenic meadows provide foraging subsidies for white-tailed deer in fragmented forest ecosystems

“…In regions that experience harsh winters with cold temperatures and regular snowfall, such as northeast Ohio where this study took place, high-quality foraging opportunities for deer are scarce across all patch types because herbaceous food items have fully senesced and are of poor nutritional quality(Schmitz 1992; Van Soest 2018). Moreover, masting crops that were available during autumn have mostly been consumed by other wildlife or cached by small mammals, and are not a reliable food source(Wolff 1996;Fay et al 2023). When there is a lack of food present on the landscape, deer employ a broad foraging strategy in which they decrease selectivity to meet their dietary needs(Berteaux et al 1998;Dumont et al 2005).…”