John H. Young

Genetic diversity, population structure, and movements of mountain lions (Puma concolor) in Texas

Abstract Knowledge of population boundaries and long-distance movements is important for wildlife conservation. We used genetic tools to investigate genetic diversity, population structure, and movements of mountain lions (Puma concolor) in Texas. We amplified 11 microsatellite loci for 245 individuals collected during 1985–2010 from Texas and New Mexico. Bayesian clustering and values of FST suggested a partitioning of mountain lions into 3 genetically differentiated groups, New Mexico, western Texas, and southern Texas. New Mexico and western Texas exhibited moderate levels of genetic diversity (expected heterozygosity [HE] = 0.61 and 0.58, respectively), whereas diversity in southern Texas was lower (HE = 0.47). Southern Texas displayed elevated genetic structure when compared to western Texas and New Mexico (FST = 0.102–0.148), whereas the comparison between New Mexico and western Texas revealed less subdivision (FST = 0.056). We documented long-distance movement among regions, and New Mexico and western Texas were sources for putative dispersers we sampled outside known populations. Differences in genetic structure and diversity between southern and western Texas support the designation of separate management units. Southern Texas appears isolated and further investigation is needed to determine the current population status. Mountain lion populations in New Mexico and western Texas may be important for future recolonization into portions of the southern United States.

Activity Patterns of Two Sympatric Species of Skunks (Mephitis mephitis and Spilogale gracilis) in Texas

Abstract We used radiotelemetry to document and compare activity and movement between the western spotted skunk Spilogale gracilis, and the striped skunk Mephitis mephitis in Texas. Mephitis mephitis had a higher rate of movement than S. gracilis. Both species had highest rates of movement during autumn, coinciding with dispersal of young. With the exception of summer, M. mephitis was significantly more active than S. gracilis and generally took shorter breaks during nightly activity. We documented statistical differences in activity between species for all seasons. Highest activity of one species occurred during lowest activity of the other species, which may indicate avoidance of the larger more-dominant species, M. mephitis, by S. gracilis.

Demographic history of an elusive carnivore: using museums to inform management

Elusive carnivores present a challenge to managers because traditional survey methods are not suitable. We applied a genetic approach using museum specimens to examine how historical and recent conditions influenced the demographic history of Puma concolor in western and southern Texas, USA. We used 10 microsatellite loci and indexed population trends by estimating historical and recent genetic diversity, genetic differentiation and effective population size. Mountain lions in southern Texas exhibited a 9% decline in genetic diversity, whereas diversity remained stable in western Texas. Genetic differentiation between western and southern Texas was minimal historically (FST = 0.04, P < 0.01), but increased 2–2.5 times in our recent sample. An index of genetic drift for southern Texas was seven to eight times that of western Texas, presumably contributing to the current differentiation between western and southern Texas. Furthermore, southern Texas exhibited a >50% temporal decline in effective population size, whereas western Texas showed no change. Our results illustrate that population declines and genetic drift have occurred in southern Texas, likely because of contemporary habitat loss and predator control. Population monitoring may be needed to ensure the persistence of mountain lions in the southern Texas region. This study highlights the utility of sampling museum collections to examine demographic histories and inform wildlife management.

SURVIVAL AND MORTALITY OF COUGARS IN THE TRANS-PECOS REGION

Abstract We analyzed data from studies of cougars (Puma concolor) completed during 1982–1997 in Big Bend, Carlsbad Caverns, and Guadalupe Mountains national parks, and Big Bend Ranch State Park. We estimated annual and seasonal (hunting and non-hunting periods) rates of survival and rates of cause-specific mortality for 31 males and 29 females. In the three studies, annual rates of survival for females were higher than those for males. Seasonal rates of survival were variable between sexes and among studies; however, pooling males and females revealed that rates of survival at Carlsbad Caverns and Guadalupe Mountains national parks and Big Bend Ranch State Park were lower during hunting periods (1 September–31 March) compared to non-hunting periods (1 April–31 August). However, pooled rates of survival for males and females at Big Bend National Park were equal during hunting and non-hunting periods. Trapping was the greatest annual source of cause-specific mortality in all study areas. Shooting and unknown sources were the next greatest sources of mortality. Mortalities from intraspecific strife and natural causes were documented only in Big Bend National Park. Rates of survival for cougars in Texas and the Guadalupe Mountains of New Mexico are among the lowest in the United States. Low rate of survival should be considered when developing management plans; however, we caution against extrapolating results from limited study areas to the entire region.

Hog-Nosed Skunks (Conepatus leuconotus) Along the Gulf of Mexico: Population Status and Genetic Diversity

Abstract We examined 12 hog-nosed skunks (Conepatus leuconotus) from southern Texas and central Tamaulipas, Mexico, during 2004–2009. We amplified the entire mitochondrial-DNA control region (D-loop) from three individuals. Results indicated that these sequences were from distinct maternal lineages with 15 variable sites. However, when reduced and compared to previously published sequences, we observed a low overall pairwise difference of 0.1% (SE = 0.1%). Our results suggest that hog-nosed skunks are persisting along the Gulf Coast region of southern Texas and northern Mexico. Resumen Examinamos 12 zorrillos de lomo blanco (Conepatus leuconotus) del sur de Texas y de la región central de Tamaulipas, México, durante 2004–2009. Amplificamos en su totalidad la región control de ADN mitocondrial (D-loop) de tres individuos. Los resultados indicaron que estas secuencias fueron de linajes maternos distintos con 15 sitios variables. Sin embargo, cuando se redujeron y se compararon con las secuencias previamente publicadas, se observó una diferencia general baja de 0.1% (EE = 0.1%). Nuestros resultados sugieren que el zorrillo de lomo blanco persiste en la región costera del golfo de México del sur de Texas y del norte de México.