Ursus Americanus Floridanus Research Articles

Black Bear Behavior and Movements Are Not Definitive Measures of Anthropogenic Food Use

Increasing human-bear conflicts are a growing concern, and managers often assume bears in developed areas are food-conditioned. We examined the relationship between human-bear conflicts and food conditioning by analyzing isotopic values of hair from black bears (Ursus americanus floridanus) involved in research (n = 34) and conflicts (n = 45). We separated research bears into wild and developed subgroups based on the impervious surface within their home ranges and separated conflict bears based on observations of human food consumption (anthropogenic = observations; management = no observations). We initially assumed wild bears were not food conditioned and anthropogenic bears were. However, using isotopic values, we classified 79% of anthropogenic bears and 8% of wild bears as food conditioned. Next, we assigned these bears to the appropriate food conditioned category and used the categorizations as a training set to classify developed and management bears. We estimated that 53% of management bears and 20% of developed bears were food conditioned. Only 60% of bears captured within or using developed areas showed evidence of food conditioning. We also found that δ13C values were a better predictor of anthropogenic foods in a bear's diet than δ15N values. Our results indicate that bears in developed areas are not necessarily food conditioned and caution against management actions based on limited observations of bear behavior.

Native Mammalian Predators Can Depredate Adult Burmese Pythons in Florida

Invasive predators are of conservation concern because they contribute to species declines and extinctions worldwide. Interactions of native fauna and invasive predators can be complex, but understanding these relationships can guide management and restoration. Observations of these interactions are especially important for invaders with low detectability like Python bivittatus (Burmese Python) where data are sparse. Here, we provide the first detailed documentation of mammalian attacks on Burmese Pythons in Florida: 1 Lynx rufus (Bobcat) predation of an adult male python and 1 Ursus americanus floridanus (Florida Black Bear) non-lethal attack on an adult female python.

Multiscale consensus habitat modeling for landscape level conservation prioritization

Globally, wide-ranging carnivore populations are imperiled due to human-caused habitat fragmentation. Where populations are fragmented, habitat quantification is often the first step in conservation. Presence-only species distribution models can provide robust results when proper scales and data are considered. We aimed to identify habitat for a fragmented carnivore population at two scales and aid conservation prioritization by identifying potential future habitat fragmentation. We used location data and environmental variables to develop a consensus model using Maxent and Mahalanobis distance to identify black bear (Ursus americanus floridanus) habitat across Florida, USA. We compared areas of habitat to areas of predicted sea level rise, development, and protected areas. Local-scale models performed better than state-scale models. We identified 23,798 km2 of habitat at the local-scale and 45,703 km2 at the state-scale. Approximately 10% of state- and 14% of local-scale habitat may be inundated by 2100, 16% of state- and 7% of local-scale habitat may be developed, and 54% of state- and 15% of local-scale habitat is unprotected. Results suggest habitat is at risk of fragmentation. Lack of focused conservation and connectivity among bear subpopulations could further fragmentation, and ultimately threaten population stability as seen in other fragmented carnivore populations globally.

Fire and land cover drive predator abundances in a pyric landscape

Understanding the link between environmental factors such as disturbance events, land cover, and soil productivity to spatial variation in animal abundance is fundamental to population ecology and wildlife management. The Longleaf pine (Pinus palustris) ecosystem is an archetypal fire-mediated ecosystem, which has seen drastic reductions in land area due to fire suppression. Current restoration utilizes prescribed fire and hardwood removal, but little is known regarding how these restoration efforts influence predator spatial distributions and predator-prey interactions. We conducted a study to investigate how fire, land cover, and soil productivity influence spatial distributions of predators in a fire-mediated ecosystem. We conducted a 34-camera survey across Camp Blanding Joint Training Center, a military installation in northern Florida, and utilized N-mixture models to estimate relative abundances of mammalian predators. To conceptualize our results relative to managed prey species, we categorized predators into white-tailed deer fawn predators [i.e. coyote (Canis latrans), bobcat (Felis rufus), and Florida black bear (Ursus americanus floridanus)] and nest predators [i.e. raccoon (Procyon lotor), Virginia opossum (Didelphis virginiana), and nine-banded armadillo (Dasypus novemcinctus)]. Coyote (P = <0.001) and bobcat (P = 0.01), increased relative abundance with decreasing pyrodiversity, the number of unique time since fire values. Raccoon relative abundance increased with distance from recent burns (P = 0.02). Coyote (P = <0.001) and bobcat (P = <0.001) relative abundance also increased with proximity to hardwoods, while raccoon relative abundance decreased with proximity to pine (P = 0.02). Interestingly, there was a lack of detections of mesopredators [i.e. red fox (Vulpes Vulpes), grey fox (Urocyon cinereoargenteus), spotted skunk (Mephitis mephitis) and striped skunk (Spilogale putorius)] that were historically considered common throughout the Southeastern United States and longleaf pine ecosystems. Our results indicate that predator space use was altered by fire conditions and distances to pine and hardwood stands, which supports a predator management strategy that utilizes management tools commonly used in restoration and conservation of the LLP ecosystem to indirectly alter predator distributions, which has the potential to positively affect the management of important species within this ecosystem.

Growth Rate and Body Size at Maturity of Florida Black Bears

Abstract Growth rate and body size at maturity are important life-history traits of interest because they represent a potential source of fitness variance within a species and provide information for understanding the nutritional condition, fecundity, and dynamics of populations. My objective here was to examine the growth rate and body size at maturity of Florida black bears Ursus americanus floridanus using body length, chest girth, and body weight measurements fitted to the nonlinear von Bertalanffy, Gompertz, and logistic size-at-age growth functions. The von Bertalanffy model had the largest Akaike weight, indicating the best fit for all measurements of both sexes. Growth models showed that females grew more slowly, with a younger age at maximum growth, faster rate at which maturity was reached, and attained significantly smaller asymptotic body length, chest girth, and weight than males. A more conservative growth strategy by females to invest available energy resources to costs of reproduction, together with intrasexual selection among males for larger body size to enhance intimidating and fighting ability to increase reproductive and survival success, are implicated as determinants of the male-biased direction and degree of sexual size dimorphism. In both sexes, the presence of human food in the diet increased the asymptotic body weight from the estimate for bears consuming a natural diet, but differences were insignificant. Females consuming human food had a slightly younger age at maximum growth and continued growth in body weight for a somewhat longer duration than did conspecifics that consumed a natural diet. In contrast, males that consumed human food had a slightly older age at maximum growth and decreased body weight growth somewhat earlier than did conspecifics consuming a natural diet. Florida black bears exhibited a larger asymptotic body size, faster growth rate, and younger age at maximum growth and maturity when compared with conspecifics in other mainland populations. Recognition of Florida black bear growth rate and adult body size provides wildlife managers a foundation for implementing measurable criteria to assess trends in population health.

Securing Pet Food from Florida Black Bears and Coyotes

The Florida black bear and the coyote are both prevalent throughout the state of Florida. The number one cause of human-wildlife conflict for these two species are food attractants, including pet food. This 2-page fact sheet written by Kelley C. Anderson and Elizabeth F. Pienaar and published by the UF/IFAS Department of Wildlife Ecology and Conservation explains how to secure pets and pet food against both the Florida black bear and the coyote and keep people, pets, and wildlife safe. edis.ifas.ufl.edu/uw437

Microhabitat features influencing habitat use by Florida black bears

Understanding fine-scale habitat needs of species and the factors influencing heterogeneous use of habitat within home range would help identify limiting resources and inform habitat management practices. This information is especially important for large mammals living in fragmented habitats where resources may be scarcer and more patchily distributed than in contiguous habitats. Using bihourly Global Position System (GPS) location data collected from 10 individuals during 2011–2014, we investigated microhabitat features of areas within home ranges that received high vs. low intensity of use by Florida black bears (Ursus americanus floridanus) in north-central, Florida. We identified areas receiving high and low levels of use by bears based on their utilization distributions estimated with the dynamic Brownian bridge movement model, and performed vegetation sampling at bear locations within high- and low-use areas. Using univariate analyses and generalized linear mixed models, we found that (1) canopy cover, visual obstruction, and hardwood density were important in defining high-use sites; (2) the probability of high use was positively associated with principal components that represented habitat closer to creeks and with high canopy and shrub cover and higher hardwood densities, likely characteristic of forested wetlands; and (3) the probability of high use was, to a lesser extent, associated with principal components that represented habitat with high canopy cover, high pine density, and low visual obstruction and hardwood density; likely representing sand pine and pine plantations. Our results indicate that the high bear-use sites were in forested wetlands, where cover and food resources for bears are likely to occur in higher abundance. Habitat management plans whereby bears are a focal species should aim to increase the availability and quality of forested wetlands.

Consequences of severe habitat fragmentation on density, genetics, and spatial capture-recapture analysis of a small bear population.

Loss and fragmentation of natural habitats caused by human land uses have subdivided several formerly contiguous large carnivore populations into multiple small and often isolated subpopulations, which can reduce genetic variation and lead to precipitous population declines. Substantial habitat loss and fragmentation from urban development and agriculture expansion relegated the Highlands-Glades subpopulation (HGS) of Florida, USA, black bears (Ursus americanus floridanus) to prolonged isolation; increasing human land development is projected to cause ≥ 50% loss of remaining natural habitats occupied by the HGS in coming decades. We conducted a noninvasive genetic spatial capture-recapture study to quantitatively describe the degree of contemporary habitat fragmentation and investigate the consequences of habitat fragmentation on population density and genetics of the HGS. Remaining natural habitats sustaining the HGS were significantly more fragmented and patchier than those supporting Florida’s largest black bear subpopulation. Genetic diversity was low (AR = 3.57; HE = 0.49) and effective population size was small (NE = 25 bears), both of which remained unchanged over a period spanning one bear generation despite evidence of some immigration. Subpopulation density (0.054 bear/km2) was among the lowest reported for black bears, was significantly female-biased, and corresponded to a subpopulation size of 98 bears in available habitat. Conserving remaining natural habitats in the area occupied by the small, genetically depauperate HGS, possibly through conservation easements and government land acquisition, is likely the most important immediate step to ensuring continued persistence of bears in this area. Our study also provides evidence that preferentially placing detectors (e.g., hair traps or cameras) primarily in quality habitat across fragmented landscapes poses a challenge to estimating density-habitat covariate relationships using spatial capture-recapture models. Because habitat fragmentation and loss are likely to increase in severity globally, further investigation of the influence of habitat fragmentation and detector placement on estimation of this relationship is warranted.

Reducing Human-Bear Conflicts: Bear-Resistant Trash Cans

The Florida black bear (Ursus americanus floridanus) is the only species of bear in Florida, with an estimated population of approximately 4,030 bears. Bears that eat garbage put themselves in danger. This 3-page fact sheet written by Ethan T. Noel, Elizabeth F. Pienaar, and and Mike Orlando and published by the Wildlife Ecology and Conservation Department explains how to secure human garbage from bears so that they don’t become reliant on human food sources, a condition that puts them at great risk of being killed from vehicle collisions, illegal shooting, or euthanasia.­http://edis.ifas.ufl.edu/uw429

Securing Garbage from Florida Black Bears: Why are the Appropriate Measures Not Implemented at the Municipal Level?

ABSTRACTAnthropogenic food conditioning of bears has resulted in recent increases in human–bear conflicts (HBCs) in Florida. Garbage is the leading cause of food conditioning of bears. Despite increased HBCs and related human safety concerns, municipal governments in Florida have generally not taken independent steps to prevent HBCs through altered garbage management. Rather, governments have relied on the Florida Fish and Wildlife Conservation Commission to manage garbage-related HBCs. We used semi-structured interviews to identify obstacles to securing garbage from bears at the municipal level. Respondents included local government administrations and waste service providers. Political and economic costs of implementing bear-resistant garbage management practices were the major obstacles to securing garbage. Respondents argued that households will not pay for, or support, the implementation of bear-resistant trash cans. Recent adoption by four counties of ordinances requiring residents to secure their garbage from bears suggests that objections to adopting bear-resistant garbage management were overstated.

Effects of environmental factors and landscape features on movement patterns of Florida black bears

AbstractA greater understanding of how environmental factors and anthropogenic landscape features influence animal movements can inform management and potentially aid in mitigating human–wildlife conflicts. We investigated the movement patterns of 16 Florida black bears (Ursus americanus floridanus; 6 females, 10 males) in north-central Florida at multiple temporal scales using GPS data collected from 2011 to 2014. We calculated bi-hourly step-lengths and directional persistence, as well as daily and weekly observed displacements and expected displacements. We used those movement metrics as response variables in linear mixed models and tested for effects of sex, season, and landscape features. We found that step-lengths of males were generally longer than step-lengths of females, and both sexes had the shortest step-lengths during the daytime. Bears moved more slowly (shorter step-lengths) and exhibited less directed movement when near creeks, in forested wetlands, and in marsh habitats, possibly indicating foraging behavior. In urban areas, bears moved more quickly (longer step-lengths) and along more directed paths. The results were similar across all temporal scales. Major roads tended to act as a semipermeable barrier to bear movement. Males crossed major roads more frequently than females but both sexes crossed major roads much less frequently than minor roads. Our findings regarding the influence of landscape and habitat features on movement patterns of Florida black bears could be useful for planning effective wildlife corridors and understanding how future residential or commercial development and road expansions may affect animal movement.

Securing Bird Feeders from Florida Black Bears

The Florida black bear (Ursus americanus floridanus) is the only species of bear in Florida, with an estimated population of approximately 4,030 bears. Bears are excellent climbers and can access bird feeders that are suspended from trees. This 3-page fact sheet explains how to secure bird seed from bears so that they don’t become reliant on human food sources, a condition that puts them at greater risk of being killed from vehicle collisions, illegal shooting, or euthanasia. Written by Ethan T. Noel and Elizabeth F. Pienaar, and published by the Wildlife Ecology and Conservation Department, March 2017.

Food habits of a small Florida black bear population in an endangered ecosystem

Abstract The Highlands–Glades subpopulation (HGS) of Florida, USA, black bears (Ursus americanus floridanus) is small, genetically depauperate, and resides primarily within the endangered Lake Wales Ridge ecosystem, which has lost >85% of native habitat to land development. Habitat loss can reduce availability of critical natural foods and cause bears to increase reliance on anthropogenic foods (i.e., human-sourced); lands supporting the HGS are expected to lose >50% of remaining Florida black bear habitat in coming decades. We used scat analysis to describe seasonal food habits, investigate potential dietary responses to food shortages, and inform habitat conservation and human–bear conflict management. Florida black bears in the HGS mostly relied on native soft and hard mast and invertebrates, which are all available in endangered scrub habitat communities. Corn dispensed at hunter-operated feeding stations was a dominant food item in scats; and other alternative foods, such as citrus fruit and white-ta...

Estimating the Live Body Weight of American Black Bears in Florida

Abstract Measuring the live body weight of large-bodied animals can be impractical when equipment needed to weigh individuals is inadequate or unavailable. My objective here was to develop a model to accurately estimate the live body weight of black bears Ursus americanus floridanus in Florida based on the relationship between scale weight and sex, morphometric measurements, and age predictor variables obtainable in the field. I used an information-theoretic approach to evaluate simple and multiple linear regression models with 70% of the data, and evaluated the best model in the set using the remaining 30%. A sex-specific model was sustained because the intercept and coefficient of age variable in female and male modeled relationships differed significantly. Chest girth2 was the best single predictor of body weight in each sex. A model including age, age2, and body length variables was better supported than chest girth2 alone. I also created a reduced model to estimate body weight when personnel may not have an opportunity to determine a bear's age. Even though there was decreasing support for the reduced model, differences between the observed and estimated body weight of all models applied to the validation data set were not significant. The 95% confidence interval on the bias of the best model ranged from −1.9 to 1.6 kg in females and −1.4 to 2.1 kg in males. The 95% confidence interval of the reduced model ranged from −1.8 to 2.3 kg in females and −2.5 to 0.5 kg in males. The body weight estimation models can be used to provide more live body weight data from handled black bears in Florida that are not weighed with a scale.

Home Ranges and Habitat Selection by Black Bears in a Newly Colonized Population in Florida

Understanding how animals use space and resources in newly colonized, anthropogenically altered habitats is important for species management because animals in fragmented habitats may use the landscape differently than conspecifics in contiguous habitats. We collected GPS-location data for 16 individuals (6 females, ages 1–9 y; 10 males, ages 2–8 y) from the summer of 2011 to the summer of 2013 to study space and habitat use by a recently established population of Ursus americanus floridanus (Florida Black Bear) in a fragmented landscape of north-central Florida. Average (± 1 SE) female and male homerange sizes estimated using the kernel density method were 31.16 ± 8.23 km2 and 220.93 ± 28.48 km2, respectively. Average 95% minimum convex polygon estimates were 34.49 ± 12.76 km2 for females and 226.04 ± 45.32 km2 for males. Home ranges in our study area were generally larger than those reported for Black Bears inhabiting the nearby contiguous forested habitat of Ocala National Forest, indicating that fragmentation may influence home-range size. Compositional analysis and generalized linear mixed models revealed that Black Bears selected most strongly for riparian forests; urban areas were generally avoided. These results suggest that large carnivores that inhabit fragmented landscapes may require more space than conspecifics in habitats with better connectivity, and highlight the importance of riparian forests for Black Bears.

Conflicts between People and the Florida Black Bear

An adult black bear may eat up to the equivalent calorie content of 38 Big Mac sandwiches a day, and can smell food from one to two miles away. Garbage is the main attractant, but bears are also attracted by bee hives, pet food, barbeque grills, fruit trees, and bird (or wildlife) feeders. Conflicts between people and black bears arise when people fail to remove or secure potential food sources. In their search for food, black bears may damage property and threaten, injure, or kill pets and livestock in order to gain access to their feed. This 5-page fact sheet provides tips for preventing human-bear conflicts and tells how to report conflicts if they happen. Written by Elizabeth F. Pienaar and published by the UF Department of Wildlife Ecology and Conservation, September 2014.

Testing Bear-Resistant Trash Cans in Residential Areas of Florida

Abstract Human—bear interactions in Florida are becoming more common as human populations grow and as the range of Ursus americanus floridanus (Florida Black Bear) increases and bears adapt to finding food in a human-modified environment. The number of calls to the Florida Fish and Wildlife Conservation Commission (FWC) concerning human—bear interactions increased from approximately 1000 calls in 2000 to more than 4000 in 2010. Almost 70% of the calls received in 2010 were related to bears consuming garbage or other unnatural foods (e.g., pet food) in residential areas. Therefore, the FWC used telephone surveys in 2 Florida communities to evaluate the effectiveness of using 2 types of bear-resistant trash cans. Surveys revealed a significant reduction in the number of bears consuming garbage and of other human—bear interactions over a 1-year period and, consequently, a positive attitude from residents toward using these trash cans. Apportioning the cost of issuing bear-resistant trash cans, however, remai...

Florida Bears and Beekeeping

The Florida black bear (Ursus americanus floridanus) is a minor predator of beehives in Florida with the potential to cause major destruction. Large-scale urban and agricultural development inexorably reduces prime bear habitat each year. This habitat also contains excellent bee forage, and so bears and bees will sometimes come in contact, thus resulting in bear predation. This revised 2-page fact sheet was written by Malcolm T. Sanford and James D. Ellis, and published by the UF Department of Entomology and Nematology, August 2012. ENY-105/AA133: Florida Bears and Beekeeping (ufl.edu)

Denning Ecology of Florida Black Bears in North-Central Florida

We studied the denning chronology, den type, and den-site characteristics of Ursus americanus floridanus (Florida Black Bear) in Ocala National Forest (ONF) and the adjacent residential area of Lynne, FL. We monitored 35 radio-collared females for 62 den years from 1999 through 2003. Den entry dates did not differ between parturient females (females that gave birth to cubs during the winter) and nonparturient (solitary females or females with yearlings) (P = 0.139). Females with cubs exited dens later (P < 0.001), and denned longer (mean =113 ± 3.3 days) than females without cubs (mean = 54 ± 6.0 days; P < 0.001). Among females with cubs, primiparous females entered dens on average 28 days later than multiparous females (P = 0.003); however, exit date and duration of denning did not differ between the two groups. Female bears denned in ground nests most frequently (n = 45), followed by excavated dens (n = 7); one female used a tree den. Compositional analysis revealed that denning habitat selection occurred in ONF, with sand pine as the preferred denning habitat, followed by swamp and pine flatwoods habitats. Denning habitat selection was not evident in Lynne, although the majority of females denned in swamp habitats. Parturient females often denned in ecotones with dense vegetation, due perhaps to the fact that such ecotones offer better protection to the female and her cubs from potential predators and weather elements. Habitat management activities should be limited during peak denning of parturient females, from late December to mid-April, particularly in Sand Pine - xeric oak and pine flatwood - swamp ecotones.

Black Bears, Palms, and Giant Palm Weevils: An Intraguild Mutualism

In peninsular Florida, USA, the palm-feeding guild is dominated by the black bear (Ursus americanus floridanus, Pallas) and the giant palm weevil (Rhynchophorus cruentatus, Fabricius). Bears damage palms by consuming their hearts, allowing the weevil to reproduce within the exposed palm tissue. The giant palm weevil reproductively benefits from bear-damaged palms, and bears gain a valuable fat-rich food supply from consuming the insects, an apparent intraguild mutualism. We analyzed a natural experiment across widely distributed sites based on presence or absence of bear populations to test the hypothesis that the presence of bears increases the abundance of the giant palm weevil. Results support the hypothesis; data also show greater attraction of females than males to pheromone traps and indicate a predominance of activity by the insect during the day and at lower summer temperatures. This interaction closely resembles one previously documented involving indigenous humans in Amazonia.