No description available.

A new subspecies of the plains pocket gopher (Geomys bursarius ozarkensis), located in the Ozark Mountains of north central Arkansas, was recently described by Elrod et al. (2000). Current range for G. b. ozarkensis was established, habitat preference was assessed by analyzing soil samples, vegetation and distance to stream and potential pocket gopher habitat within the current range was identified. A census technique was used to estimate a total density of 3, 564 pocket gophers. Through automobile and aerial survey 51 known fields of inhabitance were located extending the range slightly. Soil analyses indicated loamy sand as the most common texture with a slightly acidic pH and a broad range of values for other measured soil parameters and 21 families of vegetation were identified. All inhabited fields were located within an average of 107.2m from waterways and over 1,600 hectares of possible suitable habitat was identified.

No description available.

No description available.

This research utilized population genetic analyses (protein starch-gel electrophoresis and DNA sequencing of the cytochrome b mtDNA gene), host-parasite specificity (lice coevolution), remote sensing of satellite data, and geographic information systems (GIS) to characterize newly discovered populations of pocket gophers (genus: Geomys) in Arkansas. These populations are isolated and occur in seemingly unsuitable habitat in the Ozark Mountains of Arkansas. Analyses of electrophoretic and ectoparasite data suggested the populations in the Ozark Mountains represented isolates allied to Geomys bursarius, a species not known to occur in Arkansas. Comparison of mitochondrial DNA sequence data of the cytochrome b gene with that of other taxa and morphometric analyses confirmed that these populations are most closely allied to G. bursarius occurring to the north in Missouri. Moreover, these mtDNA sequence analyses indicated a degree of differentiation typical of that between other subspecies of pocket gophers. Therefore, these populations represent a distinct genetic entity in an intermediate stage of speciation and should be designated as a new subspecies, Geomys bursarius ozarkensis. Molecular clock analysis revealed a time of lineage divergence for this new subspecies as approximately 511,000 YBP. Due to the isolated nature and limited distribution of this subspecies, an evaluation of critical habitat needs was initiated. Remote sensing and GIS technologies were used to identify and describe suitable habitat Computerized classification of satellite imagery of suitable vegetation, integrated with ancillary digital information on soil associations, roads, and water systems, revealed that human activity had played a positive role in the establishment and dispersal of pocket gophers in this area. This research represents an initial combination of classical systematic tools with remote sensing and GIS to investigate biogeographic patterns and evolution. This project establishes a framework for using an interdisciplinary approach to studying organisms with limited distributions, determining evolutionary status, and providing recommendations for conservation.

No description available.

Thesis--University of Florida. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 145-152).

The Northern Pocket Gopher (Thomomyst alpoides) is common on open range lands at high altitudes, and range management personnel have long been confronted with the problem of controlling gopher populations. Although some studies indicate that pocket gophers have little or no injurious effects on range in good condition, other studies show that large populations of these animals can seriously damage seeded ranges and ranges in poor condition (Colorado State University Exp, Stat., 1960). Julander, Low, and Morris (1969) indicate that in areas where gophers have reached populations of 27-39 gophers per acre, forage removal by gophers may be from 4.75 to 7 pounds of fresh weight vegetation per acre per day. This converts to 435-670 pounds of airdry plant material per acre per year. On depleted ranges this represents a large percentage of the total annual growth. Hansen (1965) reported that in 1961 gophers numbered 52 per acre on Black Mesa, Colorado, Such a high density of gophers could have drastic effects on range soils and vegetation.

The purpose of this study was to determine the morphological differences in the osteology and musculature of the thoracic limb of the pocket gopher and kangaroo rat. This was accomplished by first, collection of specimens, second, the preservation and preparation of bones and muscles tor study and illustration, third, sketching and photograph­ing the sketches, fourth, noting and recording origins and insertions as well as any differences in the modification of anatomy with relation to habitat requirements. These two closely related families, Geomyide and Heteromyidae, show great morphological differences. Comparative volumetric measurements show that the forelimb of the pocket gopher is approximately twice the size of the fore­limb of the kangaroo rat. Differences in the myology were found in relative length, thickness, shape, overall size, and in origin and insertion. Variations were also found in the osteology of the two forms. These differences were gen­eral outline, locations of the tuberosities for muscle attach­ment and in the length and placement of the various bone processes.

Genic data from two chromosomal races of Geomys bursarius from a contact zone in central Texas indicated that the two races possessed distinct gene pools which would define them as separate species. Data from proteins encoded from 21 loci in this study substantiated this hypothesis. A pattern of alternately fixed alleles at the ADH-l, MDH-2, LDH-l, and IDH-1 loci with no apparent gene flow in zones of contact strongly suggested that these two races should be designated as separate species. Levels of heterozygosity and high FST values indicate that genomic structuring within Geomys is most heavily influenced by high levels of inbreeding and low migration rates. Fossorial rodents were suggested to undergo speciation primarily through parapatric means.