Modern extirpation of the Texas kangaroo rat, Dipodomys elator, in Oklahoma: changing land use and climate over a century of time as the road to eventual extinction (original) (raw)
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Conservation of the Stephens' kangaroo rat(Dipodomys stephensi): Planning for persistence
Bulletin of the …, 1991
The Stephens' kangaroo rat (Dipodomys stephensi, Family Heteromyidac) is an endangered desert rodent of southern California. The historic range of D. stephensi has been severely reduced by urban and agricultural development, and remaining habitat is considerably fragmented. We estimated the minimum viable population size of D. stephensi from a demographic model that incorporated information about survivorship and fecundity in relation to stochastic variation in rainfall. According to the model, a population of 13,210 individuals has a 95% probability of persisting for 100 years. At a density of 10 individuals/ha, this value corresponds to a reserve size of 1321 ha. Based on this estimate and maps of current distribution, land use, and soil type, we suggested nine potential reserve sites and recommended that at least three reserves be established to secure persistence.
Distribution of Ord's kangaroo rats in southeastern Alberta /
2003
Ord's kangaroo rat (Dipodomys ordii) occurrence in Alberta is well documented for the Middle Sand Hills; however, there was sufficient uncertainty regarding this endangered species' distribution in the province to warrant specialized surveys in other sand hill areas. We conducted surveys for kangaroo rats during 2001 in the vicinities of Hilda, Manyberries, and Purple Springs because each of these areas appeared to have the sandy soils and sand hill landforms that kangaroo rats require. Discovery of kangaroo rat populations in any of these areas would be significant because it could potentially reduce or refute the apparent geographic isolation of the northern population. Surveys consisted of searching at night for kangaroo rats, their conspicuous tracks, and burrows, on foot with bright flashlights and from a 4WD vehicle with spotlights. From May through August 2001 we conducted 88 nights of field surveys, during which we searched 31 subjectively selected sites and 95 random transects for kangaroo rat presence. We discovered one small population of kangaroo rats in a new vicinity near the Middle Sand Hills, on the south side of the South Saskatchewan River in Townships 20 and 21, Range 1, W4 (approximately 16 km north of the Hilda sand hills). Kangaroo rats were not discovered inhabiting any other locales that were previously undocumented. We consider the likelihood that Hilda, Manyberries, and Purple Springs sand hills harbour undetected populations of kangaroo rats is negligible. Although we discovered one small population on the south side of the South Saskatchewan River, our surveys reaffirmed that kangaroo rats have a limited geographic distribution in Alberta and are presumably genetically isolated from more southern conspecifics. vi
2016
ABSTRACTBurrows of the endangered giant kangaroorat, Dipodomys ingens, were found on the U.S. Department of Energy’s Naval Petroleum Reserves in Kern County, California. The majority of burrows (63%) were found in areas of low relief (4.3 ± 0.5°, n=32) on valley floors but 28% were unexpectedly found on low relief areas (6.4 ± 0.8°, n=39) in the uplands. Burrows were not distributed in proportion to the arealextend of the soil series, but were concentrated in deep alluvial sandy loams. Well pads were the most frequently observed (73% of 211) humandisturbance in the vicinity of burrows, but they were the most distant (150± 61m, n=150). Dirt roads were observed closer to burrows (50 ± 10 m, n=28) but less frequently (4%). Only 8 burrows were found in the vicinity of proposed petroleum developments but no projects had to me modified to avoid negatively affecting the species.RESUMEN.—Madrigueras de las ratas canguro, Dipodomys ingens, a riesgo de extinsioń, fueron localizadas en el Depa...
An evaluation of monitoring methods for the endangered giant kangaroo rat
2012
Accurate, reliable, and efficient monitoring methods for detecting changes in the distribution and abundance of wildlife populations are the cornerstone of effective management. Aerial surveys of active burrow sites and ground counts of open burrows have been used to estimate distribution and abundance, respectively, of a number of rodent species. We compared the efficacy of these and other methods for estimating distribution, abundance, and population growth of the endangered giant kangaroo rat (Dipodomys ingens) to determine the best practices for monitoring. Specifically, we compared aerial surveys, rapid expert assessments, and live-trapping for estimating giant kangaroo rat range, and burrow counts and live-trapping for estimating abundance and growth. We carried out the study in the Carrizo Plain National Monument, California, USA, from 2007 to 2011. Expert rapid assessment of sites performed nearly as well as trapping in determining range extent, while aerial surveys provided estimates of total range extent but with less precision. Active burrow counts were adequate to determine relative abundance averaged over multiple years, but were not reliable as an estimate of annual population size or growth. ß 2012 The Wildlife Society.
Microhabitat use and population decline in banner-tailed kangaroo rats
Journal of Mammalogy, 2003
Numbers of banner-tailed kangaroo rats, Dipodomys spectabilis, have declined sharply in some but not all populations monitored in southeastern Arizona over the past 20 years. We describe concurrent changes in vegetation and report the results of microhabitat manipulation experiments in which we removed broom snakeweed, Gutierrezia sarothrae, from 1.00-ha (pilot) or 0.56-ha (replicate follow-up) plots. D. spectabilis became extinct on control plots, but populations remained stable on plots where snakeweed was removed. On a larger scale, declines in numbers of kangaroo rats coincided with increases in density of woody plants. The data substantiate the preferences of this species for structurally open microhabitats and document that survival rates are higher in areas that are more open. Large kangaroo rat species like D. spectabilis are often regarded as keystone species, and our results indicate that they are vulnerable to grassland degradation.
Banner-tailed kangaroo rat burrow mounds and desert grassland habitats
Journal of arid environments, 1999
In this study, the density of banner-tailed kangaroo rat Dipodomys spectabilis mounds across a range of habitat types near Las Cruces, New Mexico was determined. Mound density varied four-fold between sites. Mound, vegetation and soil characteristics that might explain mound density variation were examined. Mounds influenced vegetation and soil characteristics by altering plant cover, and this effect varied between sites. Mound density, and soil and vegetation characteristics varied substantially between sites, but the two types of variation were not strongly related. Soil particles )2 mm diameter tended to correlate positively with mound density. Banner-tailed kangaroo rat density, measured as mound density, may be positively associated with abundance of annual grasses and forbs.
MAMMALS OF RED SLOUGH WILDLIFE MANAGEMENT AREA, WITH COMMENTS ON MCCURTAIN COUNTY, OKLAHOMA
nsrl.ttu.edu
Red Slough Wildlife Management Area (RSWMA) is located in the southeastern corner of Oklahoma, McCurtain County, and represents the extreme northwestern extent of the South Central Plains (SCP) ecoregion. Previous mammal research in southeastern Oklahoma has focused mostly on the Ouachita Mountains to the north of RSWMA. As a result, of the 69 species of mammals potentially occurring in McCurtain County, only 48 species represented by 599 voucher specimens reside in natural history collections. We present results from a mammal survey of RSWMA conducted from December 2009 to August 2010. We captured 574 non-volant small mammals in 9,115 trap-nights, 11 bats in 17 net-nights, and seven salvaged meso-mammals resulting in 157 voucher specimens of 22 mammal species, including the first specimen of Castor canadensis for McCurtain County, and photographic vouchers for eight additional species from RSWMA. These results provide a baseline for future studies on RSWMA and substantially increase our natural history knowledge for many relatively under-studied mammals in southeastern Oklahoma.
Annotated Checklist of the Mammals of the Four Canyon Preserve, Ellis County, Oklahoma
A survey of The Nature Conservancy's Four Canyon Preserve in Ellis County, Oklahoma, was conducted from June 2005 to April 2006 to determine what species of mammals occur in the preserve. Sherman live traps were used to trap small mammals and reliable sight records documented large mammals. Mist nets and gopher traps were set to sample for bats and gophers, respectively. A literature search identified historical accounts of mam-mals and those species that might eventually be found to occur in the preserve. Compiled in this inventory is an annotated list of the 33 extant species of mammals that presently occur on the Four Canyon Preserve. Also listed are 4 introduced species, 9 species that probably occurred in the preserve historically and 24 species that might be found to oc-cur. © 2010 Oklahoma Academy of Science.