The Nine‐banded Armadillo (Dasypus novemcinctus) is a widespread burrowing species with an expanding geographic range across the southeastern and midwestern United States. Armadillos dig numerous, large burrows within their home ranges and these burrows are likely used by a diverse suite of wildlife species as has been reported for other burrowing ecosystem engineers such as Gopher Tortoises (Gopherus polyphemus), Desert Tortoises (Gopherus agassizi), and Black‐tailed Prairie Dogs (Cynomys ludovicianus). We used motion‐triggered game cameras at 35 armadillo burrows in 4 ecoregions of Arkansas and documented 19 species of mammals, 4 species of reptile, 1 species of amphibian, and 40 species of bird interacting with burrows. Bobcat (Lynx rufus), Coyote (Canis latrans), Eastern Cottontail (Sylvilagus floridanus), Gray Fox (Urocyon cinereoargenteus), Gray Squirrel (Sciurus carolinensis), Northern Raccoon (Procyon lotor), Virginia Opossum (Didelphis virginiana), and unidentified rodents (mice and rats) were documented using burrows in all four ecoregions. We documented wildlife hunting, seeking shelter, rearing young in, and taking over and modifying armadillo burrows. The rate of use was highest in the Mississippi Alluvial Valley, a landscape dominated by agriculture, where natural refugia may be limited and rodents are abundant. Armadillo burrows are clearly visited and used by numerous wildlife species to fulfill various life stage requirements, and this list will likely expand if more attention is devoted to understanding the role of armadillos burrows. Armadillos are important ecosystem engineers, and their ecological role warrants more investigation and attention as opposed to only being viewed and managed as agricultural and garden pests.
As the human footprint upon the landscape expands, wildlife seeking to avoid human contact are losing the option of altering their spatial distribution and instead are shifting their daily activity patterns to be active at different times than humans. In this study, we used game cameras to evaluate how human development and activity were related to the daily activity patterns of the nine‐banded armadillo (Dasypus novemcinctus) along an urban to rural gradient in Arkansas, USA during the winter of 2020–2021. We found that armadillos had substantial behavioral plasticity in regard to the timing of their activity patterns; >95% of armadillo activity was nocturnal at six of the study sites, whereas between 30% and 60% of activity occurred during the day at three other sites. The likelihood of diurnal armadillo activity was best explained by the distance to downtown Fayetteville (the nearest population center) and estimated ambient sound level (both indices of human activity) with armadillos being most active during the day at quiet sites far from Fayetteville. Furthermore, armadillo activity occurred later during the night period (minutes after sunset) at sites near downtown and with higher anthropogenic sound. Anecdotal evidence suggests that the observed activity shift may be in response to not only human activity but also the presence of domestic dogs. Our results provide further evidence that human activity has subtle nonlethal impacts on even common, widespread wildlife species. Because armadillos have low body temperatures and basal metabolism, being active during cold winter nights likely has measurable fitness costs. Nature reserves near human population centers may not serve as safe harbors for wildlife as we intend, and managers could benefit from considering these nonlethal responses in how they manage recreation and visitation in these natural areas.
Although it is widely accepted that juvenile turtles experience high levels of predation, such events are rarely observed, providing limited evidence regarding predator identities and how juvenile habitat selection and availability of sensory cues to predators affects predation risk. We placed three-dimensional printed models resembling juvenile box turtles (Terrapene carolina) across habitats commonly utilized by the species at three sites within their geographical range and monitored models with motion-triggered cameras. To explore how the presence or absence of visual and olfactory cues affected predator interactions with models, we employed a factorial design where models were either exposed or concealed and either did or did not have juvenile box turtle scent applied on them. Predators interacted with 18% of models during field trials. Nearly all interactions were by mesopredators (57%) and rodents (37%). Mesopredators were more likely to attack models than rodents; most (76%) attacks occurred by raccoons (Procyon lotor). Interactions by mesopredators were more likely to occur in wetlands than edges, and greater in edges than grasslands. Mesopredators were less likely to interact with models as surrounding vegetation height increased. Rodents were more likely to interact with models that were closer to woody structure and interacted with exposed models more than concealed ones, but model exposure had no effect on interactions by mesopredators. Scent treatment appeared to have no influence on interactions by either predator group. Our results suggest raccoons can pose high predation risk for juvenile turtles (although rodents could also be important predators) and habitat features at multiple spatial scales affect predator-specific predation risk. Factors affecting predation risk for juveniles are important to consider in management actions such as habitat alteration, translocation, or predator control.
The geographic range of the nine-banded armadillo (Dasypus novemcinctus) has rapidly been expanding within the United States for the last 150 years. One of the factors contributing to this astounding range expansion is the species’ ability to survive in and colonize human-dominated areas. Despite the fact that armadillos live alongside humans in numerous towns and cities across the Southeastern, Southcentral, and now Midwestern United States, we know relatively little about the behavior and ecology of armadillos in human-developed areas. Here, we used motion-triggered game cameras in over 115 residential yards in the rapidly developing Northwest corner of Arkansas to survey armadillos in a largely suburban environment. Our objectives were to explore trends in armadillo occupancy and daily activity patterns in a suburban setting. We documented armadillos in approximately 84% of the yards surveyed indicating that the species was widespread throughout the environment. We found that the species was more likely to occupy yards surrounded by a high proportion of forest cover. We found no relationship between armadillo occupancy and other land cover or development covariates. Only 2% of nearly 2000 armadillo detections occurred during the day indicating that the species is almost exclusively nocturnal during the summer months when living near humans in the suburban environment, which we suggest is likely an adaptation to avoid contact with humans and their dogs. As the armadillo continues to expand its geographic range to areas where it has not previously occurred, understanding how human development supports and facilitates the spread of this species can elucidate areas where conflict between humans and armadillos might occur allowing for preemptive management or education to mitigate conflict.
Aim: The assembly of species into communities and ecoregions is the result of interacting factors that affect plant and animal distribution and abundance at biogeographic scales. Here, we empirically derive ecoregions for mammals to test whether human disturbance has become more important than climate and habitat resources in structuring communities.Location: Conterminous United States.Time Period: 2010–2021.Major Taxa Studied: Twenty‐five species of mammals.Methods: We analysed data from 25 mammal species recorded by camera traps at 6645 locations across the conterminous United States in a joint modelling framework to estimate relative abundance of each species. We then used a clustering analysis to describe 8 broad and 16 narrow mammal communities.Results: Climate was the most important predictor of mammal abundance overall, while human population density and agriculture were less important, with mixed effects across species. Seed production by forests also predicted mammal abundance, especially hard‐mast tree species. The mammal community maps are similar to those of plants, with an east–west split driven by different dominant species of deer and squirrels. Communities vary along gradients of temperature in the east and precipitation in the west. Most fine‐scale mammal community boundaries aligned with established plant ecoregions and were distinguished by the presence of regional specialists or shifts in relative abundance of widespread species. Maps of potential ecosystem services provided by these communities suggest high herbivory in the Rocky Mountains and eastern forests, high invertebrate predation in the subtropical south and greater predation pressure on large vertebrates in the west.Main Conclusions: Our results highlight the importance of climate to modern mammals and suggest that climate change will have strong impacts on these communities. Our new empirical approach to recognizing ecoregions has potential to be applied to expanded communities of mammals or other taxa.
Wildlife translocation is an often-used technique to augment populations or remove animals from harm’s way. Unfortunately, many translocation efforts fail to meet their goals for myriad reasons, particularly because translocated animals make large, erratic movements after release, which can result in high mortality rates. Soft release, holding animals in acclimation pens for some period of time at the recipient site before release, has been proposed as a technique to reduce these large movements and increase the survival of translocated animals. Here, we compared the survival and movement patterns of soft-released Texas horned lizards (Phrynosoma cornutum) with resident lizards, as well as hard-released lizards from a prior study. Juvenile lizards that were soft-released had high survival rates similar to resident lizards, despite still moving more frequently and occupying larger home ranges than residents. Conversely, soft-released adult lizards had survival rates similar to those that were hard-released, and much lower rates than resident adults. Curiously, soft-released adults did not have significantly higher movement rates or home range sizes than residents. Our results suggest that caution should be used before adult Texas horned lizards are translocated. However, juveniles responded well to soft release, and future research should explore whether they are more resilient to translocation in general, or if soft release provided a specific survival advantage. Contrary to our predictions, the survival of translocated animals was not related to their post-release movement patterns, and the mechanism underlying the observed survival patterns is unclear.