Geology topics

C.P. Qualls

Publications and source records attributed to C.P. Qualls.

3 recordsLinked to original sources

USGS2011

Distribution and habitat utilization of the gopher tortoise tick (Amblyomma tuberculatum) in southern Mississippi

The distribution of the gopher tortoise tick ( Amblyomma tuberculatum ) has been considered intrinsically linked to the distribution of its primary host, gopher tortoises ( Gopherus polyphemus ). However, the presence of G. polyphemus does not always equate to the presence of A. tuberculatum . There is a paucity of data on the ecology, habitat preferences, and distribution of A. tuberculatum . The goals of this study were to assess the distribution of A. tuberculatum in southern Mississippi and to determine which, if any, habitat parameters explain the distribution pattern of A. tuberculatum . During 2006–2007, we examined 13 G. polyphemus populations in southern Mississippi for the presence of A. tuberculatum , and we measured a suite of habitat parameters at each site. Only 23% of the G. polyphemus populations supported A. tuberculatum , suggesting a more restricted distribution than its host. The results of our multivariate analyses identified several habitat variables, e.g., depth of sand and percentage of sand in the topsoil and burrow apron, as being important in discriminating between sites with, and without, A. tuberculatum . Amblyomma tuberculatum was only found at sites with a mean sand depth of >100 cm and a mean percentage of topsoil and burrow apron sand composition >94.0 and 92.4, respectively. Thus, environmental factors, and not just its host's range, seem to influence the distribution of A. tuberculatum .

Mississippi↗

USGS2011

The effects of isolation on the demography and genetic diversity of long-lived species: Implications for conservation and management of the gopher tortoise (Gopherus polyphemus)

In the southeastern United States, habitat loss has fragmented the landscape and isolated many populations of this region's flora and fauna, which has presumably resulted in smaller population sizes and reduced levels of genetic diversity. For example, forestry practices and anthropogenic disturbances are both cited as factors fragmenting the once extensive range of Gopherus polyphemus. One localized, but extreme, source of fragmentation was the impoundment of the Chattahoochee River in 1963 to form Walter F. George Reservoir along the border of Georgia and Alabama. The formation of this reservoir isolated populations of G. polyphemus on two newly created islands providing a natural laboratory to explore the demographics and genetic effects of fragmentation on a long-lived species. These populations were first surveyed in 1984 and, 21 years later, we revisited them to collect demographic data and tissue samples for genetic analysis. We genotyped all individuals for 10 microsatellite loci, and we tested these data for bottlenecks and compared them to levels of genetic diversity for populations from other portions of the range. We found 45 and two individuals on the larger and smaller islands, respectively. On the large island, however, the population size was identical to the 1984 survey. Only the population structure based on estimated age differed between the 1984 and 2004 surveys, while population size structure based on carapace length, sex ratio, and sex-specific growth rates did not differ. The population of the large island showed genetic evidence of a past bottleneck. The genetic diversity indices from the population of the large island, however, were comparable to or greater than those found at mainland sites, in particular from western populations.

Herpetological Conservation and Biology↗

USGS2010

Morphological and molecular reassessment of graptemys oculifera and Graptemys flavimaculata (Testudines: Emydidae)

The turtle genus Graptemys consists of 15 recognized taxa, distinguished largely on the basis of pigmentation pattern (i.e., soft tissue and shell), head size, and shell morphology. However, phylogenetic studies have shown limited sequence divergence within the genus and between Graptemys oculifera and Graptemys flavimaculata relative to most other members of the Emydidae. Graptemys oculifera of the Pearl River drainage and G. flavimaculata of the Pascagoula River drainage have been recognized as species since 1890 and 1954, respectively. However, the description of G. flavimaculata was based on a limited number of morphological characters. Several of these characters overlap between G. flavimaculata and G. oculifera, and no attempt was made to test for significant morphological differentiation. In this study, we reevaluated the morphological and genetic distinctiveness of G. flavimaculata and G. oculifera with (1) multivariate statistical analyses of 44 morphological characters and (2) 1,560 bp of sequence data from two mitochondrial genes (control region and ND4). The morphological and molecular analyses produced incongruent results. The principal components analysis ordinations separated the two species along a pigmentation gradient with G. flavimaculata having more yellow pigmentation than G. oculifera. Likewise, clustering analyses separated the specimens into two distinct groups with little overlap between the species. Our mitochondrial data supported previous findings of limited genetic differentiation between the two species. However, the results of our morphological analyses, in conjunction with recently published nuclear gene sequence data, support the continued recognition of the two species. Copyright 2010 Society for the Study of Amphibians and Reptiles.

Conference Paper↗