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Local ecological niche models, genotype associations and environmental data for desert tortoises.


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Inman, R.D., and Esque, T.C., 2019, Local ecological niche models, genotype associations and environmental data for desert tortoises: U.S. Geological Survey data release,


These data include environmental covariates used to develop species distribution models for Gopherus agassizii and Gopherus morafkai, along with PCA-reduced environmental covariates used to explore local species-environment relationships within a subregion of the ectone between the two species. We also provide the genotype association used to test the mapped clusters of multiscale geographically weighted regression coefficients against models of (i) a geographically-based taxonomic designation these two sister species, and (ii) an environmental ecoregion designation. These data support the following publication: Inman et al. 2019. Local niche differences predict genotype associations in sister taxa of desert tortoise. Diversity and [...]

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Point of Contact :
Rich D Inman
Originator :
Rich D Inman, Todd C Esque
Metadata Contact :
Rich D Inman
USGS Mission Area :
SDC Data Owner :
Western Ecological Research Center
Distributor :
U.S. Geological Survey - ScienceBase

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Local ecological niche models, genotype associations and environmental data for desert tortoises.xml
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To investigate spatial congruence between ecological niches and genotype in two allopatric species of desert tortoise that are species of conservation concern. The relationships between the distributions of species and their ecological properties has long been central to biogeographical inquiry. Here we develop a case study of two sister taxa to explore geographic patterns of niche differences between them, with focus on their differing conservation status. We use species distribution modelling (SDM) and multiscale geographically weighted regression (MGWR) in a coupled modeling approach to identify differences in the ecological niches of G. agassizii and G. morafkai, and explore spatially varying species-environment relationships in the recent secondary contact zone. We 1) formally test for differences in their ecological niches, 2) identify boundaries represented by differences in their niches, and 3) determine which of three spatial delineations better describes landscape patterns of genotypic variation. These delineations include A) the Colorado River (the current geographic boundary defining each species), B) the Mojave and Sonoran Basin and Range ecotone, and C) geographic patterns in local niche differences identified in this study. The results of this study will inform conservation planning across the transition zone of these two species.


The authors of these data require that data users contact them regarding intended use and to assist with understanding limitations and interpretation. Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.


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  • USGS Data Release Products
  • USGS Western Ecological Research Center



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Type Scheme Key
DOI doi:10.5066/P91V2S8C

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