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Jonathan A. Jenks

Publications and source records attributed to Jonathan A. Jenks.

33 records · Page 2Linked to original sources
USGS2013

Influence of landscape characteristics on retention of expandable radiocollars on young ungulates

One tool used for wildlife management is the deployment of radiocollars to gain knowledge of animal populations. Understanding the influence of individual factors (e.g., species, collar characteristics) and landscape characteristics (e.g., forested cover, shrubs, and fencing) on retention of expandable radiocollars for ungulates is important for obtaining empirical data on factors influencing ecology of young-of-the-year ungulates. During 2001–2009, we captured and radiocollared 198 white-tailed deer (Odocoileus virginianus) fawns, 142 pronghorn (Antilocapra americana) fawns, and 73 mule deer (O. hemionus) fawns in South Dakota, Minnesota, and California, USA. We documented 72 (36.4%), 8 (5.6%), and 7 (9.6%) premature (2, SE = 0.1, n = 75) compared with areas where fawns shed collars (x = 3.24 km/km 2 , SE = 0.1, n = 56) prior to 270 days. Researchers of fawns should consider that radiocollars can be shed prematurely when estimating desired sample size to yield a suitable strength of inference about some natural process of interest.

California;Minnesota;South Dakota↗
USGS2013

Techniques for capturing bighorn sheep lambs

Low lamb recruitment is a major challenge facing managers attempting to mitigate the decline of bighorn sheep ( Ovis canadensis ), and investigations into the underlying mechanisms are limited because of the inability to readily capture and monitor bighorn sheep lambs. We evaluated 4 capture techniques for bighorn sheep lambs: 1) hand-capture of lambs from radiocollared adult females fitted with vaginal implant transmitters (VITs), 2) hand-capture of lambs of intensively monitored radiocollared adult females, 3) helicopter net-gunning, and 4) hand-capture of lambs from helicopters. During 2010–2012, we successfully captured 90% of lambs from females that retained VITs to ≤1 day of parturition, although we noted differences in capture rates between an area of high road density in the Black Hills (92–100%) of South Dakota, USA, and less accessible areas of New Mexico (71%), USA. Retention of VITs was 78% with pre-partum expulsion the main cause of failure. We were less likely to capture lambs from females that expelled VITs ≥1 day of parturition (range = 80–83%) or females that were collared without VITs (range = 60–78%). We used helicopter net-gunning at several sites in 1999, 2001–2002, and 2011, and it proved a useful technique; however, at one site, attempts to capture lambs led to lamb predation by golden eagles ( Aquila chrysaetos ). We attempted helicopter hand-captures at one site in 1999, and they also were successful in certain circumstances and avoided risk of physical trauma from net-gunning; however, application was limited. In areas of low accessibility or if personnel lack the ability to monitor females and/or VITs for extended periods, helicopter capture may provide a viable option for lamb capture.

Colorado;New Mexico;South Dakota↗
USGS2013

Effects of plant phenology and vertical height on accuracy of radio-telemetry locations

The use of very high frequency (VHF) radio-telemetry remains wide-spread in studies of wildlife ecology and management. However, few studies have evaluated the influence of vegetative obstruction on accuracy in differing habitats with varying transmitter types and heights. Using adult and fawn collars at varying heights above the ground (0, 33, 66 and 100 cm) to simulate activities (bedded, feeding and standing) and ages (neonate, juvenile and adult) of deer Odocoileus spp., we collected 5,767 bearings and estimated 1,424 locations (28-30 for each of 48 subsamples) in three habitat types (pasture, grassland and forest), during two stages of vegetative growth (spring and late summer). Bearing error was approximately twice as large at a distance of 900 m for fawn (9.9°) than for adult deer collars (4.9°). Of 12 models developed to explain the variation in location error, the analysis of covariance model (HT*D + C*D + HT*TBA + C*TBA) containing interactions of height of collar above ground (HT), collar type (C), vertical height of understory vegetation (D) and tree basal area (TBA) was the best model (w i = 0.92) and explained ∼ 71% of the variation in location error. Location error was greater for both collar types at 0 and 33 cm above the ground compared to 66 and 100 cm above the ground; however, location error was less for adult than fawn collars. Vegetation metrics influenced location error, which increased with greater vertical height of understory vegetation and tree basal area. Further, interaction of vegetation metrics and categorical variables indicated significant effects on location error. Our results indicate that researchers need to consider study objectives, life history of the study animal, signal strength of collar (collar type), distance from transmitter to receiver, topographical changes in elevation, habitat composition and season when designing telemetry protocols. Bearing distances in forested habitat should be decreased (approximately 23% in our study) compared to bearing distances in open habitat to maintain a consistent bearing error across habitats. Additionally, we believe that field biologists monitoring neonate ungulates for habitat selection should rely on visual locations rather than using VHF-collars and triangulation.

South Dakota↗
USGS2012

Greater sage-grouse winter habitat use on the eastern edge of their range

Greater sage-grouse (Centrocercus urophasianus) at the western edge of the Dakotas occur in the transition zone between sagebrush and grassland communities. These mixed sagebrush (Artemisia sp.) and grasslands differ from those habitats that comprise the central portions of the sage-grouse range; yet, no information is available on winter habitat selection within this region of their distribution. We evaluated factors influencing greater sage-grouse winter habitat use in North Dakota during 2005–2006 and 2006–2007 and in South Dakota during 2006–2007 and 2007–2008. We captured and radio-marked 97 breeding-age females and 54 breeding-age males from 2005 to 2007 and quantified habitat selection for 98 of these birds that were alive during winter. We collected habitat measurements at 340 (177 ND, 163 SD) sage-grouse use sites and 680 random (340 each at 250 m and 500 m from locations) dependent sites. Use sites differed from random sites with greater percent sagebrush cover (14.75% use vs. 7.29% random; P < 0.001), percent total vegetation cover (36.76% use vs. 32.96% random; P ≤ 0.001), and sagebrush density (2.12 plants/m 2 use vs. 0.94 plants/m 2 random; P ≤ 0.001), but lesser percent grass cover (11.76% use vs. 16.01% random; P ≤ 0.001) and litter cover (4.34% use vs. 5.55% random; P = 0.001) and lower sagebrush height (20.02 cm use vs. 21.35 cm random; P = 0.13) and grass height (21.47 cm use vs. 23.21 cm random; P = 0.15). We used conditional logistic regression to estimate winter habitat selection by sage-grouse on continuous scales. The model sagebrush cover + sagebrush height + sagebrush cover × sagebrush height (w i = 0.60) was the most supported of the 13 models we considered, indicating that percent sagebrush cover strongly influenced selection. Logistic odds ratios indicated that the probability of selection by sage-grouse increased by 1.867 for every 1% increase in sagebrush cover (95% CI = 1.627–2.141) and by 1.041 for every 1 cm increase in sagebrush height (95% CI = 1.002–1.082). The interaction between percent sagebrush canopy cover and sagebrush height (β = −0.01, SE ≤ 0.01; odds ratio = 0.987 [95% CI = 0.983–0.992]) also was significant. Management could focus on avoiding additional loss of sagebrush habitat, identifying areas of critical winter habitat, and implementing management actions based on causal mechanisms (e.g., soil moisture, precipitation) that affect sagebrush community structure in this region.

Journal of Wildlife Management↗
USGS2012

Predator evasion by white-tailed deer fawns

Despite their importance for understanding predator–prey interactions, factors that affect predator evasion behaviours of offspring of large ungulates are poorly understood. Our objective was to characterize the influence of selection and availability of escape cover and maternal presence on predator evasion by white-tailed deer, Odocoileus virginianus, fawns in the northern Great Plains, U.S.A. We observed 45 coyote, Canis latrans, chases of fawns, and we participated in 83 human chases of fawns during 2007–2009, of which, 19 and 42 chases, respectively, ended with capture of the fawn. Evasive techniques used by fawns were similar for human and coyote chases. Likelihood of a white-tailed deer fawn escaping capture, however, was influenced by deer group size and a number of antipredator behaviours, including aggressive defence by females, initial habitat and selection of escape cover, all of which were modified by the presence of parturient females. At the initiation of a chase, fawns in grasslands were more likely to escape, whereas fawns in forested cover, cultivated land or wheat were more likely to be captured by a coyote or human. Fawns fleeing to wetlands and grasslands also were less likely to be captured compared with those choosing forested cover, wheat and cultivated land. Increased probability of capture was associated with greater distance to wetland and grassland habitats and decreased distance to wheat. Use of wetland habitat as a successful antipredator strategy highlights the need for a greater understanding of the importance of habitat complexity in predator avoidance.

Animal Behaviour↗
USGS2012

Microhabitat selection by bobcats in the badlands and Black Hills of South Dakota, USA: a comparison of Prairie and forested habitats

An understanding of habitat selection is important for management of wildlife species. Although bobcat (Lynx rufus) resource selection has been addressed in many regions of the United States, little work has been conducted in the Northern Great Plains. From 2006–2008 we captured and radiocollared 20 bobcats in the Badlands (n = 10) and Black Hills (n = 10) regions of South Dakota. During the summers of 2008 and 2009 we collected habitat measurements at 349 (176 Badlands, 176 Black Hills) bobcat locations and 321 (148 Badlands, 173 Black Hills) random sites. Microhabitat characteristics at bobcat use sites varied with region (P < 0.001) and sex of bobcat (P < 0.001). Percent slope, shrub, low cover, medium cover, and total cover were greater (P ≤ 0.017) at bobcat locations in the Black Hills than in the Badlands whereas distance to drainage was greater (P < 0.001) at locations in the Badlands than in the Black Hills. In the Badlands, male bobcat locations were closer (P ≤ 0.002) to prairie dog towns and drainages and had greater (P < 0.05) percent forbs and forb height than random sites, whereas females were closer to badland formations (P < 0.001) than random sites. In the Black Hills, male locations were at greater elevation (P < 0.001) and female locations were characterized by greater (P ≤ 0.02) grass height, shrub height, low cover, and total cover than random sites. Logistic regression indicated that microhabitat selection was similar between study areas; odds ratios indicated that odds of bobcat use increased by 0.998 (95% CI = 0.997–0.999) per 1 m increase in distance to drainage, 0.986 (95% CI = 0.978–0.993) per 1.0% increase in grass cover, by 1.024 (95% CI = 1.011–1.036) per 1 cm increase in grass height, by 1.013 (95% CI = 1.003–1.024) per 1% increase in forb cover, and by 1.028 (95% CI = 1.017–1.039) per 1% increase in medium cover. Our results were similar to other bobcat microhabitat selection studies, where bobcat relocations were associated with understory vegetation, drainages, and rugged terrain. These results identify the adaptability of the species to meet life history requirements in a variety of landscapes, and provide insight to how land use requirements vary within regional and management boundaries.

South Dakota↗
USGS2011

Spatial ecology of white-tailed deer fawns in the northern Great Plains: implications of loss of conservation reserve program grasslands

Few studies have evaluated how wildlife, and white-tailed deer ( Odocoileus virginianus ) in particular, respond to Conservation Reserve Program (CRP) grasslands. We conducted a 3-year study (2007&ndash;2009) to determine the influence of CRP on fawn ecology during a time of declining CRP enrollment. We captured and radiocollared 81 fawn white-tailed deer during 15 May to 15 June 2007&ndash;2009 in north-central South Dakota, collected 6,505 locations, and documented 70 summer home ranges. Mean summer home ranges increased temporally during 2007&ndash;2009 ( P < 0.001) and corresponded to a 41% loss of CRP grasslands in the area (2.3% loss in land cover and approx. 21% loss in cover habitat in the study area) over the duration of the study. Additionally, mean movement between daily locations increased ( P < 0.001) from 2007 to 2009. Analysis of covariance models indicated that change in CRP influenced home-range size, and change in CRP and wheat influenced daily movement. Smaller home ranges and reduced movements were associated with greater quantity of CRP available to fawns, and increased movements were associated with more acreage of wheat available to fawns. Fawns shifted resource selection during the summer at a mean age ranging from 48.8 days to 58.6 days, and this shift was associated with height of corn (83&ndash;87 cm). During early summer, fawns consistently selected for CRP; selection of wheat progressed temporally from avoidance in 2007 to selection in 2009. During late summer, fawns consistently selected for corn habitat and used CRP at least in proportion to its availability. Reduction in CRP-grasslands seemed to increase fawn home-range size and daily movements and, influenced change in resource selection to wheat. Current legislation mandates continued decrease in CRP enrollment and concomitant increase in the planting of corn for ethanol production. Management of habitat throughout the grasslands of the Northern Great Plains that maximizes cover habitats would provide neonates with adequate cover for protection from predators.

Great Plains↗
USGS2011

Habitat selection by female swift foxes (Vulpes velox) during the pup-rearing season

The swift fox (Vulpes velox) was historically distributed in western South Dakota including the region surrounding Badlands National Park (BNP). The species declined during the mid-1800s, largely due to habitat loss and poisoning targeted at wolves (Canis lupis) and coyotes (C. latrans). Only a small population of swift foxes near Ardmore, South Dakota persisted. In 2003, an introduction program was initiated at BNP with swift foxes translocated from Colorado and Wyoming. We report on habitat use by female swift foxes during the pup-rearing season (May&ndash;July) in 2009. Analyses of location data from 13 radiomarked female foxes indicated disproportional use ( P < 0.001) of some habitats relative to their availability within swift fox home ranges. Swift foxes used grassland ( &#374 = 1.01), sparse vegetation ( &#374 = 1.43) and prairie dog towns ( &#374 = 1.18) in proportion to their availability, whereas they were less likely to use woodland ( &#374 = 0.00), shrubland ( &#374 = 0.14), pasture/agricultural-land ( &#374 = 0.25) and development ( &#374 = 0.16) relative to availability. Swift foxes typically are located in habitats that provide greater visibility, such as shortgrass prairie and areas with sparse vegetation; which allow detection of approaching coyotes (e.g., primary predator of swift foxes).

South Dakota↗
USGS2010

Evaluating detection probabilities for American marten in the Black Hills, South Dakota

Assessing the effectiveness of monitoring techniques designed to determine presence of forest carnivores, such as American marten (Martes americana), is crucial for validation of survey results. Although comparisons between techniques have been made, little attention has been paid to the issue of detection probabilities (p). Thus, the underlying assumption has been that detection probabilities equal 1.0. We used presence-absence data obtained from a track-plate survey in conjunction with results from a saturation-trapping study to derive detection probabilities when marten occurred at high (>2 marten/10.2 km2) and low (???1 marten/10.2 km2) densities within 8 10.2-km2 quadrats. Estimated probability of detecting marten in high-density quadrats was p = 0.952 (SE = 0.047), whereas the detection probability for low-density quadrats was considerably lower (p = 0.333, SE = 0.136). Our results indicated that failure to account for imperfect detection could lead to an underestimation of marten presence in 15-52% of low-density quadrats in the Black Hills, South Dakota, USA. We recommend that repeated site-survey data be analyzed to assess detection probabilities when documenting carnivore survey results.

Journal of Wildlife Management↗
USGS2008

Factors affecting road mortality of white-tailed deer in eastern South Dakota

White-tailed deer ( Odocoileus virginianus ) mortalities (n = 4,433) caused by collisions with automobiles during 2003 were modeled in 35 counties in eastern South Dakota. Seventeen independent variables and 5 independent variable interactions were evaluated to explain deer mortalities. A negative binomial regression model (Ln Y = 1.25 &ndash; 0.12 [percentage tree coverage] + 0.0002 [county area] + 5.39 [county hunter success rate] + 0.0023 [vehicle proxy 96&ndash;104 km/hr roads], model deviance = 33.43, &chi; 2 = 27.53, df = 27) was chosen using a combination of a priori model selection and AICc. Management options include use of the model to predict road mortalities and to increase the number of hunting licenses, which could result in fewer DVCs.

South Dakota↗
USGS2007

Determinants of elephant distribution at Nazinga Game Ranch, Burkina Faso

We used seasonal ground total counts and remote sensing and GIS technology to relate elephant (Loxodonta africana africana) distribution at Nazinga Game Ranch to environmental and anthropogenic factors. Variables used in analyses were normalized difference vegetation index, elevation, stream density, density of poaching and human illegal activities, distance to dams, distance to rivers, distance to roads, and distance to poaching risk. Contrary to our expectation, road traffic did not disturb elephants. Strong negative relationships were documented between elephant abundance and stream density, distance to dams, and poaching density. Density of poaching and other human illegal activities explained 81%, vegetation greenness 6%, and stream density 3% of the variation in elephant density. Elephant distribution represented a survival strategy affected by poaching, food quality and abundance, and water availability.

Nazinga Game Ranch↗
USGS2006

Evaluating genetic viability of pronghorn in Wind Cave National Park

The pronghorn (Antilocapra americana) was reintroduced into Wind Cave National Park, South Dakota, in 1914 and thus, has inhabited the Park for almost a century. A decline in the population has raised concern for the continued existence of pronghorn inside Wind Cave National Park. Historically, pronghorn numbers reached greater than 300 individuals in the 1960&rsquo;s but declined to about 30 individuals by 2002. The primary objective of our study was to evaluate genetic characteristics of pronghorn to determine if reduced heterozygosity contributed to the decline of pronghorn in Wind Cave National Park. Microsatellite DNA was collected from 75 pronghorn inhabiting Wind Cave National Park in western South Dakota (n = 11), northwestern South Dakota (n = 33), and southwestern South Dakota (n = 31). Pronghorn in Wind Cave National Park had similar levels of observed heterozygosity (0.473 to 0.594) and low inbreeding coefficients (-0.168 to 0.037) when compared with other populations in western South Dakota. Furthermore, indices of population structure indicated no differentiation occurred among pronghorn populations. Results indicated that genetic variability was not a primary factor in the decline of pronghorn in Wind Cave National Park.

Prairie Naturalist↗
USGS2001

Use of the USDA Forest Service Geographic Information System for determining cover type use by white-tailed deer

Cover type use by white-tailed deer (Odocoileus virginianus dacotensis) in the central Black Hills of South Dakota was compared to the United States Department of Agriculture (USDA) Forest Service digital data using a Geographic Information System (GIS). Cover types were determined from observations of radiocollared deer and random locations and from corresponding point locations in the Forest Service digital data. Cover type information was collected at 3,145 white-tailed deer locations and 1,044 random locations. On winter range, cover types determined from observations of radiocollared deer included pine (Pinus ponderosa), pine-deciduous, aspen (Populus tremuloides), aspen-coniferous, burned pine, and meadows; cover types determined from Forest Service data included pine, aspen, grasslands, and private land. On summer range, cover types determined from observations of radiocollared deer included pine, pine-deciduous, aspen, aspen-coniferous, white spruce (Picea glauca), white spruce-deciduous, and meadows; cover types determined from Forest Service digital map data included pine, aspen, grasslands, and private land. Cover types used by white-tailed deer compared to the Forest Service data resulted in 42% agreement on summer range and 62% agreement on winter range. On winter and summer range, Forest Service data tended to overestimate ponderosa pine and aspen habitats used by white-tailed deer, while failing to account for mixed (secondary) cover types. To improve the accuracy of habitat management decisions relative to white-tailed deer, the Forest Service GIS would be strengthened if mixed (secondary) cover type classifications were included in the database.

South Dakota, Wyoming↗
USGS1995

Characteristics of mineral licks used by white-tailed deer (Odocoileus virginianus)

Characteristics of mineral licks used by white-tailed deer ( Odocoileus virginianus ) were examined in the northern Black Hills of South Dakota in May 1992. Concentrations of sodium, nitrogen, phosphorus, potassium, calcium, chloride and magnesium, and soil texture, organic matter and pH for licks and nonlick soils were compared. Black Hills lick and nonlick samples also were compared to 67 other North American licks characterized by Jones and Hanson (1985). Degree of use (high or low), and vegetative and topographic characteristics also were determined. Use of mineral licks by deer was highest in spring and early summer; mineral licks were not used by deer in winter. Mostly adult females, and on a few occasions fawns visited licks. Soil texture was finer and organic matter was lower (P < 0.05) in lick than nonlick soils. Soil pH, soluble salts, sodium and nitrate nitrogen were higher (P < 0.05) in lick than in nonlick soils. Chloride was the only mineral that differed (P = 0.03) between high-use and low-use licks but was not considered important in lick selection. Sodium was the primary mineral sought by white-tailed deer using mineral licks.

American Midland Naturalist↗