Danielle Walkup

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• Doctor of Philosophy
• Research Assistant Professor at Texas A&M University

Translocated herpetofauna can exhibit irregular space use and movement patterns when compared with resident conspecifics. In Florida, USA, Gopher Tortoises (Gopherus polyphemus) are translocated throughout the state to mitigate habitat loss due to development. The postrelease space use of translocated Gopher Tortoises within soft-release pens can a...

Texas Alligator Lizards (Gerrhonotus infernalis) range from Central Texas into adjacent northeastern Mexico, and published ecological studies on their terrestrial and arboreal movement patterns are lacking. We used radiotelemetry to assess movements, annual home range, and arboreal activity of G. infernalis at Bamberger Ranch Preserve, Blanco Count...

Simple Summary The disappearance of many reptiles and amphibian species is directly and indirectly connected with habitat modification, introducing invasive species, disease, pollution, and climate change. Monitoring endangered species is essential for conservation action to mitigate the predominant threats to endangered species. According to wildl...

The behaviors and activity season of Deirochelys reticularia miaria (Western Chicken Turtle) are poorly understood in Texas. Though distribution of D. r. miaria in the eastern portion of the state is widespread, turtle assemblage studies conducted within the range of the species in Texas have seldom documented its presence. There is a lack of forma...

Novel technologies, such as camera traps, have expanded the opportunities for species detection, especially for rare species. Corresponding changes in data processing must occur to handle the large volume of data gathered from technology like camera traps. Automated image data processing, usually by running images through different types of compute...

The reproductive lifespans of turtles are consistently long, but reproductive cycles are under environmental control and thus can vary within species, populations, and individuals over time and space. Knowledge of turtle species' reproductive traits and their associated variances over time and space are critical to understanding the dynamics of tur...

Mapping species distributions and habitat suitability guides policy decisions and conservation. Over the last few decades, multiple expert-derived, qualitative species occurrence and habitat availability maps have been developed in response to increasing conservation attention on the Dunes Sagebrush Lizard (Sceloporus arenicolus). Management and co...

The Dunes Sagebrush Lizard (Sceloporus arenicolus) is endemic to the Mescalero-Monahans Sandhills, in southeastern New Mexico and west Texas. It only lives in dunes with bowl-shaped depressions (blowouts) that are semi-stabilized by shinnery oak (Quercus havardii). Meticulous studies reveal population dynamics in these lizards scale from local neig...

The Western Massasauga (Sistrurus tergeminus) is a small North American rattlesnake found west of the Mississippi River. Sistrurus tergeminus has previously been divided into two putative subspecies, Desert (S. t. edwardsii) and Prairie Massasaugas (S. t. tergeminus) based upon qualitative variation in morphology, coloration, and habitat. The Deser...

The western massasauga (Sistrurus tergeminus) is a small pit viper with an extensive geographic range, yet observations of this species are relatively rare. They persist in patchy and isolated populations, threatened by habitat destruction and fragmentation, mortality from vehicle collisions, and deliberate extermination. Changing climates may pose...

The conservation of rarely encountered species is notoriously difficult mainly because of the lack of information about their natural history. This is definitely the case for the spot-tailed earless lizards (Holbrookia lacerata and H. subcaudalis). Sparse distributional records and infrequent observations at known sites were used as evidence to pet...

Phylogeographic divergence and population genetic diversity within species reflect the impacts of habitat connectivity, demographics, and landscape level processes in both the recent and distant past. Characterizing patterns of differentiation across the geographic range of a species provides insight on the roles of organismal and environmental tra...

Context Advancements in camera-trap technology have provided wildlife researchers with a new technique to better understand their study species. This improved method may be especially useful for many conservation-reliant snake species that can be difficult to detect because of rarity and life histories with secretive behaviours. Aims Here, we repo...

Phylogeographic divergence and population genetic diversity within species reflect the impacts of habitat connectivity, demographics, and landscape level processes in both the recent and distant past. Characterizing patterns of differentiation across the geographic range of a species provides insight on the roles of organismal and environmental tra...

Context Understanding how species are distributed throughout landscapes requires knowledge of the hierarchy of habitat selection made by individuals, the resulting spatiotemporal structure of demography, and the consequent dynamics of localized populations. Objectives We examined how patterns of habitat use, settlement, and vacancy in an endemic h...

Several habitats may be required for an animal's persistence, and movements within and among these habitats characterise an ani-mal's home range. For species of lizards, variation in home range size is typically best explained by either sit-and-wait or active foraging styles. In this study, we explore movements, home range size, and territoriality...

We estimated occupancy and extinction probabilities for the Dunes Sagebrush Lizard (Sceloporus arenicolus) for part of its range in Texas, to increase our understanding of the distribution of this species and to evaluate the map that identifies areas according to Very High, High, Low, and Very Low categories of likelihood-of-occurrence. This map, d...

The future for the Reptilia will be one of continued discovery of the extant diversity of species in every group and continued challenges for their conservation. Most species will persist, albeit in smaller and increasingly fragmented geographic ranges, and highly vulnerable species will require active conservation measures to ensure their survival...

Context Research has shown many negative effects of roads and traffic on wildlife and other biodiversity. The direct and indirect mechanisms through which roads and traffic harm animal populations vary across taxa, making mitigation of road effects a great challenge for conservation. As such, a large toolkit of species-specific management technique...

Landscape fragmentation alters biotic and abiotic characteristics of landscapes, variously affecting the size and demographic structure of species' populations. Fragmentation is predicted to negatively impact habitat specialists because of perturbations to their habitat, whereas generalists should be less sensitive to fragmentation. Differences in...