Development of species distribution models (SDMs) and application of them has been expanding very rapidly over the past few years. Often based on simple occurrence data like that provided by the Fishes of Texas project, they summarize and make these data sets useful in new ways and across large spatial extents. They have proven useful in diverse applications such as conservation planning, climate change studies, disease ecology, invasive species research, and community ecology.As a first step toward many future landscape-scale geospatial analyses using Fishes of Texas data, we developed powerful predictive computer models of species’ distributions using commonly accepted practices and modeling algorithms and provide them here so that others may use them in their own research and applications. Our models provide continuous coverages of probabilities of species occurrences across all cells of a fine-scale grid extending across all of Texas, thus effectively “filling in the blanks” between the actual occurrences that we know to be distributed in non-random ways as a result of diverse historic factors such as collectors' interests, gears, landowner permission, etc.
We developed these models using only the most precisely located recent occurrence records in the Fishes of Texas database together with recent climate and physical environmental data. These models have now been thoroughly tested and demonstrated to be powerful predictors of actual occurrences under current conditions. They were constructed in such a way that the probability values in the models can be interpreted as indicators of suitability of habitat that are mostly independent of large scale land and water development influences such as diversions or dams.
Mapped modeled probabilities of species occurrences can be viewed and model outputs formatted for analysis may be downloaded via the model class table below. At this time only Model Class 01 are available for download.
When using models, please cite as suggested in the How to cite models section of the Fishes of Texas documentation.
Terrapene coahuila is one of four extant species of North American box turtles. It is restricted in distribution to the Cuatro Ciénegas Basin in Coahuila, México. Results of previous examinations of extant T. carolina and T. ornata revealed relatively high levels of morphological variation, but morphological studies of T. coahuila are rare, and data on skeletal morphology are limited. We examined 214 skeletal specimens of T. coahuila and documented variation in 51 mensurative and discrete characters of the carapace and plastron. Overall levels of variation are low, as predicted by previously documented levels of gene flow between the sub-populations of the species. However, significant polymorphism is present in the positions of the anterior and posterior sulci of the fourth vertebral scute and the configuration of neural bones 2, 3, and 7. Additionally, co-ossification of the carapacial bones varies substantially within the sample, but independently of carapace length. Genetic, epigenetic, and environmental controls for those features are not known. In addition to documenting skeletal morphology within T. coahuila, we provide new perspectives on patterns of variation within Terrapene, and contribute data that should help paleontologists to establish more rigorous criteria for the identification of fossil specimens of North American box turtles. Those data will be especially important for critical evaluation of recently discovered early and middle Tertiary fossils that are yielding new insights into the evolution of box turtles and the modernization of the turtle biota.