Spatial genetic structure in American black bears (Ursus americanus): female philopatry is variable and related to population history.

Previously, American black bears (Ursus americanus) were thought to follow the pattern of female philopatry and male-biased dispersal. However, recent studies have identified deviations from this pattern. Such flexibility in dispersal patterns can allow individuals greater ability to acclimate to changing environments. We explored dispersal and spatial genetic relatedness patterns across ten black bear populations-including long established (historic), with known reproduction >50 years ago, and newly established (recent) populations, with reproduction recorded <50 years ago-in the Interior Highlands and Southern Appalachian Mountains, United States. We used spatially explicit, individual-based genetic simulations to model gene flow under scenarios with varying levels of population density, genetic diversity, and female philopatry. Using measures of genetic distance and spatial autocorrelation, we compared metrics between sexes, between population types (historic and recent), and among simulated scenarios which varied in density, genetic diversity, and sex-biased philopatry. In empirical populations, females in recent populations exhibited stronger patterns of isolation-by-distance (IBD) than females and males in historic populations. In simulated populations, low-density populations had a stronger indication of IBD than medium- to high-density populations; however, this effect varied in empirical populations. Condition-dependent dispersal strategies may permit species to cope with novel conditions and rapidly expand populations. Pattern-process modeling can provide qualitative and quantitative means to explore variable dispersal patterns, and could be employed in other species, particularly to anticipate range shifts in response to changing climate and habitat conditions.

High seroprevalence of Toxoplasma gondii in elk (Cervus canadensis) of the central Appalachians, USA.

Toxoplasma gondii is an important protozoan parasite of mammals that impacts animal health and behavior. Although this parasite has been documented in several cervid species, including red deer (Cervus elaphus) in Europe, little is known about T. gondii impacts on the closely related North American counterpart, the elk (wapiti, Cervus canadensis), which has increased in number and expanded in range during the past century. We assessed seroprevalence of T. gondii antibodies using a modified agglutination test (MAT) (1:25 titer) and blood collected from 142 free-ranging elk in Kentucky, USA, where the species was reintroduced during 1997-2002 after over a century of absence. Eighty of 142 (56.3%) elks were seropositive for T. gondii, but we found no infection or titer differences between sexes (U = 2146, P = 0.128). However, odds of T. gondii infection significantly increased with elk age (ß = 0.429, P = 0.001) by a factor of 1.54 (95% CI 1.19-1.99), and titer increased commensurate with age (JT = 3071, P < 0.001). High prevalence of T. gondii infection in elk of this region may be explained by sympatry with two primary hosts, the bobcat and domestic cat, as well as shed oocysts in the soil of this relatively wet and humid region. We suggest that wildlife agency personnel incorporate warnings about proper elk meat preparation into their hunter education outreach programs and literature to reduce the chances for human infection from consuming contaminated venison.

Congenital Vertebral Malformation in a Neonatal Elk (Cervus canadensis) in Kentucky, USA.

We captured a <1-d-old male elk calf (Cervus canadensis) with a shortened neck. Postmortem examination revealed trauma, meconium aspiration syndrome, and cervical vertebral malformation (partial fusion and narrowed disc spaces). This observation is novel in a wild elk calf, although the gross lesions resembled complex vertebral malformation in neonatal cattle.

Seroprevalence of Toxoplasma gondii in American Black Bears ( Ursus americanus ) of the Central Appalachians, USA.

We assessed Toxoplasma gondii seroprevalence in 53 free-ranging American black bears ( Ursus americanus ) in the Central Appalachian Mountains, US. Seroprevalence was 62% with no difference between males and females or between juvenile and adult bears. Wildlife agencies should consider warnings in hunter education programs to reduce the chances for human infection from this source.