Carrion use by terrestrial vertebrates is much more prevalent than conventional theory implies, and, rather than a curiosity of animal behavior, is a key ecological process that must be accounted for. Human aversion to rotted substances and difficulties associated with identifying scavenged material in studies of food habits have contributed to the relative lack of information concerning scavenging behavior in vertebrates. Several lines of evidence, however, suggest that carrion resources are more extensively used by vertebrates than has been widely assumed: 1) a substantial number of animals die from causes other than predation and become available to scavengers, 2) a wide variety of vertebrate scavengers, rather than microbes or arthropods, consume most available carcasses, and 3) intense competition exists between vertebrate scavengers and decomposers, especially in warm climates. Although vultures are best adapted to use carrion, nearly all vertebrate predators are also scavengers to some extent. The costs and benefits associated with carrion use influences the evolution of scavenging behavior in vertebrates, resulting in a continuum of facultative scavengers that use carrion to varying degrees. The realized usage of carrion by a vertebrate species is influenced by the speed and efficiency with which it forages, its visual and olfactory abilities, and its capacity for detoxifying products of decomposition. A deeper understanding of carrion use by facultative scavengers will improve our knowledge of community and ecosystem processes, especially the flow of energy through food webs.

a b s t r a c tA growing literature in the field of road ecology suggests that vehicle/wildlife collisions are important to biologists and transportation officials alike. Roads can affect the quality and quantity of available wildlife habitat, most notably through fragmentation. Likewise, vehicular traffic on roads can be direct sources of wildlife mortality and in some instances, can be catastrophic to populations. Thus, connectivity of habitat and permeability of road systems are important factors to consider when developing road mortality mitigation systems. There are a variety of approaches that can be used to reduce the effects of roads and road mortality on wildlife populations. Here, we briefly review wildlife-crossing structures, summarize previous wildlife road mortality mitigation studies, describe common mitigation measures, and discuss factors that influence the overall effectiveness of mitigation strategies. Because there are very few road mortality studies "before" and "after" the installation of wildlife-crossing structures, their efficiency is nearly impossible to evaluate. However, simple and relatively inexpensive measures reviewed herein can almost certainly reduce the number of collisions between wildlife and automobiles.Published by Elsevier B.V.

Vertebrate scavengers and decomposers compete for animal carcasses in all temperate and tropical ecosystems. We examined the influence of carcass size, forest type, and air temperature on the fate of rodent carcasses at the Savannah River Site, South Carolina, USA. Three hundred rodent carcasses were placed at random locations in forested habitats and scavengers were identified using remote photography. Seventeen species of vertebrates removed 104 of 300 (35%) rodent carcasses over a year. Raccoons (Procyon lotor (Linnaeus, 1758)) and Virginia opossums (Didelphis virginiana Kerr, 1792) scavenged most frequently. For scavenged carcasses, the mean time to carcass removal was 2.58 days after placement. Carcass acquisition by scavengers and decomposers was influenced moderately by forest type and carcass size, although ambient air temperature considerably influenced the fate of carcasses. Vertebrates removed fewer carcasses as temperatures increased: only 28 of 144 (19%) carcasses were scavenged when temperatures exceeded 17 °C. The temporal pattern of carcass removal by vertebrates, however, did not vary with temperature. Consistent rates of carcass removal by vertebrates across the year and increased activity by insects during warm weather led to elevated levels of decomposition during summer months. This study confirms the complexity and dynamic nature of competitive relationships among scavengers and decomposers.

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Decomposition contributes to global ecosystem function by contributing to nutrient recycling, energy flow, and limiting biomass accumulation. The decomposer organisms influencing this process form diverse, complex, and highly dynamic communities that often specialize on different plant or animal resources. Despite performing the same net role, there is a need to conceptually synthesize information on the structure and function of decomposer communities across the spectrum of dead plant and animal resources. A lack of synthesis has limited cross‐disciplinary learning and research in important areas of ecosystem and community ecology. Here we expound on the “necrobiome” concept and develop a framework describing the decomposer communities and their interactions associated with plant and animal resource types within multiple ecosystems. We outline the biotic structure and ecological functions of the necrobiome, along with how the necrobiome fits into a broader landscape and ecosystem context. The expanded necrobiome model provides a set of perspectives on decomposer communities across resource types, and conceptually unifies plant and animal decomposer communities into the same framework, while acknowledging key differences in processes and mechanisms. This framework is intended to raise awareness among researchers, and advance the construction of explicit, mechanistic hypotheses that further our understanding of decomposer community contributions to biodiversity, the structure and function of ecosystems, global nutrient recycling and energy flow.

Understanding the relative hazards of wildlife to aircraft is important for developing effective management programs. We used Federal Aviation Administration National Wildlife Strike Database records from 1990 to 2009 in the United States to rank the relative hazard of wildlife to aircraft. We summarized data for 77 species or species groups with !20 records where collisions occurred 500 ft (152 m) above ground level. We also assessed the effects of avian body mass, body density, and group size on relative hazard scores. The 3 most hazardous species or species groups were mule deer (Odocoileus hemionus), white-tailed deer (O. virginianus), and domestic dogs. ''Other geese'' (snow goose [Chen caerulescens], brant [Branta bernicla], and greater white-fronted goose [Anser albifrons]) was the most hazardous bird group. Ten of the 15 most hazardous bird species or species groups are strongly associated with water. Avian body mass was strongly associated with percentage of all strikes that caused damage, but not for species exceeding median body mass (1,125 g) of birds in damaging strikes. In contrast, percentage of damaging strikes increased when multiple birds were involved, but only for those species with body mass !1,125 g. Managers should prioritize efforts that will reduce habitat suitability for those species most hazardous to aircraft. We recommend use of exclusion (e.g., fences) for managing large mammals and habitat modifications (e.g., reductions in standing water) accompanied by hazing for reducing bird use of airports. We also recommend that evaluations of jet turbine engine performance following bird ingestions consider using multiple birds with body mass >1,000 g. ß 2011 The Wildlife Society.

Animal-vehicle collisions cause high levels of vertebrate mortality worldwide, and what goes wrong when animals fail to escape and ultimately collide with vehicles is not well understood. We investigated alert and escape behaviours of captive brown-headed cowbirds (Molothrus ater) in response to virtual vehicle approaches of different sizes and at speeds ranging from 60 to 360 km h 21 . Alert and flight initiation distances remained similar across vehicle speeds, and accordingly, alert and flight initiation times decreased at higher vehicle speeds. Thus, avoidance behaviours in cowbirds appeared to be based on distance rather than time available for escape, particularly at 60-150 km h 21 ; however, at higher speeds (more than or equal to 180 km h 21 ) no trend in response behaviour was discernible. As vehicle speed increased, cowbirds did not have enough time to assess the approaching vehicle, and cowbirds generally did not initiate flight with enough time to avoid collision when vehicle speed exceeded 120 km h 21 . Although potentially effective for evading predators, the decision-making process used by cowbirds in our study appears maladaptive in the context of avoiding fast-moving vehicles. Our methodological approach and findings provide a framework to assess how novel management strategies could affect escape rules, and the sensory and cognitive abilities animals use to avoid vehicle collisions.

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.