Geology topics

Mark A. Ternent

Publications and source records attributed to Mark A. Ternent.

3 recordsLinked to original sources

USGS2020

Resource use by American black bear in suburbia: A landholder step selection approach

Range expansion of American black bear ( Ursus americanus ; bear) and residential development has resulted in a growing presence of bear in suburbia. Suburban landscapes exhibiting patchworks of variable-sized parcels and habitats and owned by landowners with diverse values, can create large areas of suitable habitats with limited public access. These landscapes thereby may limit the effectiveness of hunting as a traditional bear population management tool. Managers require better information regarding suburban landowner attitudes regarding hunting before implementing changes intended to increase bear harvest to management populations. To address this need, in 2013, we surveyed landowners to identify properties that allowed bear hunting in three suburban areas of Pennsylvania where bear sightings have increased. We then used location data obtained for 29 bears equipped with global positioning system (GPS) transmitters from 2010 to 2012 to model their resource selection in the study area. We assessed the influence of hunting access, housing density, land cover, and topographic variables on radio-marked black bear monitored 10 days before, during, and after the bear hunting season. We found that resource selection of radio-marked bear was similar for all three periods and bears selected for forested land in all three seasons and herbaceous cover in the pre- and hunting periods. Resource selection by bears was not influenced by whether land was open or closed to hunting in the pre-hunting and hunting periods, but in the post-hunting period lands not open to hunting had support as the second-best model. All radio-marked bears in our study were vulnerable to harvest. However, they did not change resource selection during the hunting season nor did they avoid areas open to hunting. Integrating human dimension data with bear habitat use studies, especially in suburban landscapes, has the potential to address bear space use and population management needs often overlooked in traditional research designs.

Pennsylvania↗

USGS2014

Hidden Markov model for dependent mark loss and survival estimation

Mark-recapture estimators assume no loss of marks to provide unbiased estimates of population parameters. We describe a hidden Markov model (HMM) framework that integrates a mark loss model with a Cormack–Jolly–Seber model for survival estimation. Mark loss can be estimated with single-marked animals as long as a sub-sample of animals has a permanent mark. Double-marking provides an estimate of mark loss assuming independence but dependence can be modeled with a permanently marked sub-sample. We use a log-linear approach to include covariates for mark loss and dependence which is more flexible than existing published methods for integrated models. The HMM approach is demonstrated with a dataset of black bears ( Ursus americanus ) with two ear tags and a subset of which were permanently marked with tattoos. The data were analyzed with and without the tattoo. Dropping the tattoos resulted in estimates of survival that were reduced by 0.005–0.035 due to tag loss dependence that could not be modeled. We also analyzed the data with and without the tattoo using a single tag. By not using.

Journal of Agricultural, Biological, and Environme↗

USGS2002

Grizzly bear denning chronology and movements in the Greater Yellowstone Ecosystem

Den entrance and emergence dates of grizzly bears ( Ursus arctos ) in the Greater Yellowstone Ecosystem are important to management agencies that wish to minimize impacts of human activities on bears. Current estimates for grizzly bear denning events use data that were collected from 1975–80. We update these estimates by including data obtained from 1981–99. We used aerial telemetry data to estimate week of den entry and emergence by determining the midpoint between the last known active date and the first known date denned, as well as the last known date denned and the first known active date. We also investigated post emergence movement patterns relative to den locations. Mean earliest and latest week of den entry and emergence were also determined. Den entry for females began during the fourth week in September, with 90% denned by the fourth week of November. Earliest den entry for males occurred during the second week of October, with 90% denned by the second week of December. Mean week of den entry for known pregnant females was earlier than males. Earliest week of den entry for known pregnant females was earlier than other females and males. Earliest den emergence for males occurred during the first week of February, with 90% of males out of dens by the fourth week of April. Earliest den emergence for females occurred during the third week of March; by the first week of May, 90% of females had emerged. Male bears emerged from dens earlier than females. Denning period differed among classes and averaged 171 days for females that emerged from dens with cubs, 151 days for other females, and 131 days for males. Known pregnant females tended to den at higher elevations and, following emergence, remained at higher elevation until late May. Females with cubs remained relatively close (<3 km) to den sites until the last 2 weeks in May. Timing of denning events was similar to previous estimates for this and other grizzly bear populations in the southern Rocky Mountains.

Wyoming↗