Mesopredators dominate competition for carrion in an agricultural landscape

Abstract

The role of carrion in food webs is governed by complex competitive interactions among a wide range of taxa. Although this competition is known to be influenced by several biotic and abiotic factors, relatively few data are available from highly altered landscapes. We investigated the fate of mouse carcasses in an intensively farmed region in Indiana, USA, using remote cameras. Vertebrates removed 234 of 266 (88%) carcasses within two weeks after placement. Raccoons (Procyon lotor) and Virginia opossums (Didelphis virginiana) were the predominant scavengers, removing 184 of 197 (93%) carcasses for which a scavenger could be identified. Air temperature influenced carcass removal by vertebrates only at higher temperatures, with fewer carcasses removed as temperatures increased over ∼22 • C. Elevated densities of mesopredators, coupled with the reduced search area for carrion due to the sparse distribution of forested habitat, likely were responsible for the rapid discovery and high level of carcass removal by vertebrates compared to previous investigations. Our data suggest that in agricultural landscapes, the competitive balance for carrion can differ substantially from that found in more pristine habitats. Moreover, the monopolization of carrion resources by abundant mesopredators may have negative consequences for other species that use carrion. 269 entdeckt und zu einem hohen Prozentsatz von Wirbeltieren entfernt wurden. Unsere Daten legen nahe, dass in Agrarlandschaften das Konkurrenzgleichgewicht der Aasnutzer erheblich von dem in eher ursprünglichen Habitaten abweicht. Darüberhinaus könnte die Monopolisierung des Aases durch häufige Mesoprädatoren negative Konsequenzen für andere Arten, die Aas nutzen, haben. Gesellschaft für Ökologie.

Ecological Potential for Rabies Virus Transmission via Scavenging of Dead Bats by Mesocarnivores

“…Although Ravens (Corvus corax) and American Crows (Corvus brachyrhynchos) are common in Flagstaff, we recorded a crow taking a bat only once. Finally, squirrels have been reported scavenging at low levels in other studies (DeVault and Rhodes 2002;DeVault et al 2011), but in our study rock squirrels (Otospermophilus variegatus), the most common ground squirrel in urban Flagstaff, took more bat carcasses than raccoons, domestic cats, or gray foxes. These comparisons underscore that the ecologic potential for disease transmission via scavenging is likely to vary depending upon scavenger community composition and relative abundance.…”

“…More comparable to our study are studies that examined scavenging of mouse and rat carcasses. Two of these studies, in rural Indiana, found raccoons were the most important scavenger of rodent carcasses, followed by opossums (Didelphis virginianus) and gray foxes, with striped skunks taking rodent carcasses only once at each site (DeVault and Rhodes 2002;DeVault et al 2011), the opposite of the pattern we documented. Another study using rodent carcasses in the UK, found Common Crows (Corvus corax) and Eurasian Magpies (Pica pica) were important scavengers of mouse carcasses (Inger et al 2016).…”

“…Many scavenging studies done elsewhere (e.g., DeVault et al 2011;Inger et al 2016) relied on rodent carcasses because they are more readily available than bat carcasses, but whether mesocarnivores respond differently to bat versus rodent carcasses has not been tested. Within bats, species may also differ in relative attractiveness to mesocarnivores.…”

Carcasses provide resources not exclusively to scavengers: patterns of carrion exploitation by passerine birds

“…Thus, scavengers perform mutualistic-facilitatory processes for finding carrion (Jackson et al 2008) such as intra-and inter-specific exclusion and dominance phenomena, depending on the specific hierarchical position and trophic requirements thereof (Wilmers et al 2003b, DeVault et al 2011, Kendall et al 2012). Obligate scavengers with higher energy requirements, usually the larger species, monopolize the greater amount of biomass by displacing and preventing other smaller species from accessing the carrion (Shivik 2006, Blázquez et al 2009.…”

Does Grey Wolf Presence Affect Habitat Selection of Wolverines?

“…Heinrich 1988, Wilmers et al 2003, Wilmers & Post 2006, Baglione & Canestrari 2009, DeVault et al 2011. One foraging strategy that scavengers can employ to discover unpredictable food sources is to associate with predators that provide food (Stahler et al 2002).…”