Geometric theory on large-scale and local determination of density dependence of a recovering large carnivore population

Density-dependent population growth is a feature of large carnivores like wolves ($\textit{Canis lupus}$), with mechanisms typically attributed to resource (e.g. prey) limitation. Such mechanisms are local phenomena and rely on individuals having access to information, such as prey availability at their location. Using over four decades of wolf population and range expansion data from Wisconsin (USA) wolves, we found that the population not only exhibited density dependence locally but also at landscape scale. Superficially, one may consider space as yet another limiting resource to explain landscape-scale density dependence. However, this view poses an information puzzle: most individuals do not have access to global information such as range-wide habitat availability as they would for local prey availability. How would the population "know" when to slow their range expansion? To understand observed large-scale spatial density dependence, we propose a reaction-diffusion model, first introduced by Fisher and Kolmogorov, with a "travelling wave" solution, wherein the population expands from a core range that quickly achieves local carrying capacity. Early-stage acceleration and later-stage deceleration of population growth can be explained by early elongation of an expanding frontier and a later collision of the expanding frontier with a habitat boundary. Such a process does not require individuals to have global density information. We illustrate our proposal with simulations and spatial visualizations of wolf recolonization in the western Great Lakes region over time relative to habitat suitability. We further synthesize previous studies on wolf habitat selection in the western Great Lakes region and argue that the habitat boundary appeared to be driven by spatial variation in mortality, likely associated with human use of the landscape

Regulated Commercial Harvest to Manage Overabundant White-Tailed Deer: An Idea to Consider?

Dramatic growth in numbers of white-tailed deer (Odocoileus virginianus) and declines in hunter recruitment have challenged our ability to manage deer populations through traditional methods. We surveyed all state wildlife agencies and estimate the current abundance of white-tailed deer in North America exceeds 30 million. States currently are issuing record numbers of permits to hunters to increase harvest of white-tailed deer. Unfortunately, hunter participation has been declining in North America during the past two decades. Traditional methods of population management have been ineffective in reducing numbers of deer sufficiently in some environments. Regulated commercial harvest would help state wildlife agencies manage overabundant populations of white-tailed deer and allow licensed hunters to sell all or parts of harvested deer. We anticipate that many will criticize regulated commercial harvest of deer and claim that it is contrary to the North American Model of Wildlife Conservation (NAMWC). We feel, however, that regulated commercial harvest meets all seven of the pillars of the NAMWC: 1) Wildlife is a natural resource of the public trust (state wildlife agencies will manage deer and deer would continue to be a public resource). 2) No commercial use of wildlife [a direct reaction to exploitive and unsustainable market hunting in the 18th and 19th Centuries; commercial markets currently exist for other natural resources (e.g., furbearers, fish, timber); contemporary conservation values would not allow overexploitation; a framework for regulations, monitoring, and enforcement already is in place in every state]. 3) Democratic rule of law to regulate use of wildlife (commercial harvest of white-tailed deer would be highly regulated by wildlife agencies through public processes). 4) Hunting opportunity for all (anyone legally able to hold a deer hunting license would be eligible to apply for a Commercial Deer Harvest License (CDHL), CDHL programs would be implemented only where recreational hunting is inefficient or inappropriate). 5) No frivolous use of wildlife (CDHLs will be used to generate food and other products, management would address risks to human health and safety and losses of agricultural resources to deer). 6) Wildlife is an international resource [has little to do with our proposed idea of managing overabundant resident populations of white-tailed deer, but a CDHL program may be applicable to any overabundant species, including internationally migratory species, such as snow geese (Chen caerulescens)]. 7) Science-based wildlife policy (a CDHL program would rely on science and research-based data to estimate densities before, during, and after commercial harvest). A CDHL program should be managed and distributed by state wildlife agencies, issue permits only to qualified individuals, enable harvest of an allotment of deer in areas targeted for population reduction, and permit the sale of whole carcasses and parts of harvested deer. Administration of a CDHL program will be taxing. State agencies are understaffed, but administrative and enforcement frameworks already exist for commercial harvest of publicly owned natural resources (e.g. furbearers, fish, timber) and the processing and handling of meat (e.g., USDA inspections). Revenue generated by CDHL programs could be directed back to agencies and personnel that administer and oversee programs. We anticipate several issues that must be addressed for regulated commercial harvest of deer to be accepted by agencies, hunters, and the public. State laws and regulations will need to be reviewed and some will have to be changed. Some will argue that we do not have the strength, stamina, or political will necessary to implement such broad sweeping changes. On the other hand, many wildlife managers will appreciate having an alternative tool for managing overabundant populations of white-tailed deer. Several benefits (reduce overabundant populations of deer; source of healthy, natural, green, locally-produced protein; economic growth, entrepreneurship, and market expansion; and public engagement and appreciation) and concerns (privatization of wildlife; overexploitation; food safety; competition with existing commodities; law enforcement; challenges of changing laws, regulations, and attitudes) are associated with this concept. We encourage a professional discussion of regulated commercial harvest to address the issue of overabundant white-tailed deer

Effectiveness of a Simulated Pack to Manipulate Wolf Movements

Bioboundaries, also called biofences, are deterrents that attempt to exploit certain innate behaviors to exclude wildlife from target areas. We hypothesized that human-deployed scent marks and playbacks of foreign howls could simulate a territorial gray wolf (Canis lupus) pack impinging on a resident pack, thereby causing the resident pack to move. During summer 2010, we deployed a simulated-pack bioboundary near 3 wolf packs in northern Wisconsin and monitored their movements relative to 3 wolf packs experiencing a sham treatment, to control for effects of human presence. We analyzed wolves’ locations (≥1 location per week) and used linear models with mixed effects to examine distance from the rendezvous site as a function of treatment (sham or experimental) and phase of treatment (before or after treatment was initiated), while accounting for variations in individual wolves. We found little evidence that biofences, as configured and deployed in this study, caused wolves to change use of their territory

A Late Born White-tailed Deer, Odocoileus virginianus, Fawn in Southcentral Wisconsin

Published reports of peak breeding and parturition dates for White-tailed Deer (Odocoileus virginianus) indicate that deer in northern regions typically breed during November and give birth during late May and early June. However, we report a late-born White-tailed Deer fawn killed by a vehicle between 12-13 March 2007 in south central Wisconsin. Morphology measurements and body weight indicated the individual was 63-76 days old, was born between 26 December 2006 and 8 January 2007, and was conceived between 14-27 June 2006. To our knowledge, this observation represents the latest documented breeding activity in northern deer populations

Contraceptive Efficacy of a Novel Intrauterine Device (IUD) in White-Tailed Deer

Overabundant white-tailed deer (Odocoileus virginianus) pose risks to property, health, and safety of human beings. Public concerns about lethal management can impair efforts to address these issues, particularly in urban settings. Several techniques developed for reducing reproductive output of deer have limited utility because they require repeated dosing to achieve permanent effect and face uncertain regulatory approval for use beyond experimentation. From 10 August 2006 through 30 December 2007, we evaluated the contraceptive efficacy of copper-containing intrauterine devices (IUDs) implanted trans-cervically in white-tailed deer at the E.S. George Reserve in Pinckney, Michigan. Intrauterine devices were implanted before (n = 9) and shortly after (n = 10) the breeding season. Post-breeding season IUD treatment was in conjunction with a 5 cm3 dose of 5 mg/ml prostaglandin F2α (PGF2α), delivered subcutaneously. Intrauterine devices reduced pregnancy rates when administered prior to breeding (P \u3c 0.001) and prevented pregnancy for up to 2 years (the duration of the study). Two of 8 does that received IUDs prior to the breeding season and survived to the end of the study became pregnant (due to loss of the implant) during the second year while all (n = 16) does without implants conceived. Cervical changes associated with early pregnancy made trans-cervical implantation after the breeding season challenging, and resulted in improperly placed IUDs in 2 treated does. The apparent expulsion of IUDs by pregnant does that received the combined treatment after breeding suggests IUD treatment should be limited to the pre-breeding season. Intrauterine devices show potential as a tool for small-scale deer population management via non-steroidal reproductive inhibition

Using Bayesian state-space models with Age-At-Harvest data to estimate black bear abundance and demographic parameters.

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Increased stress in Asiatic black bears relates to food limitation, crop raiding, and foraging beyond nature reserve boundaries in China

AbstractAsiatic black bears (Ursus thibetanus) are declining throughout much of their range. In China they are partially protected by a nature reserve system and rely heavily on hard mast as a food source prior to winter denning. Bears may compensate for mast shortages by raiding agricultural crops and killing livestock, mainly outside reserves where they are exposed to increased threats of poaching. We hypothesized that stress would vary with availability of high-quality refugia and fluctuations in mast abundance. We collected fecal samples from free-ranging bears in and around nature reserves in southwestern China, recorded habitat characteristics at each fecal sample location, and quantified abundance of hard mast. We used feces for genetic and endocrine analysis and identified 106 individuals. Feces collected outside reserves, or in agricultural fields within reserves, contained elevated concentrations of glucocorticoid metabolites compared to samples collected in intact, mast-producing forests within reserves. Relationships with habitat variables indicated that the hypothalamic–pituitary–adrenal (HPA) axis of the Asiatic black bear is responsive to human activity, abundance of hard mast, extent of forest cover, and quality of diet. Our findings demonstrate biological reactions of a large mammal to variable forest quality, human threats, and foraging relative to boundaries of protected areas