Conservation Genetics

, Volume 19, Issue 4, pp 937–946 | Cite as

Genetic structure and environmental niche modeling confirm two evolutionary and conservation units within the western spadefoot (Spea hammondii)

  • Kevin M. Neal
  • Benjamin B. Johnson
  • H. Bradley Shaffer
Research Article


The western spadefoot (Spea hammondii) is a Species of Special Concern in California and is now under review by the U.S. Fish and Wildlife Service for listing under the Endangered Species Act. We delineated potential conservation units within S. hammondii by analyzing spatial genetic structure across the species’ range using five nuclear and one mitochondrial loci. For both nuclear and mitochondrial markers we found that S. hammondii consists of two genetically distinct, allopatric clusters divided by the Transverse Ranges. To corroborate the northern and southern genetic clusters as conservation units from an ecological perspective, we applied a niche identity test to environmental niche models of the two groups. We found that the niche models of the northern and southern clusters were significantly different, suggesting they may be ecologically non-exchangeable. Given our demonstration of significant genetic and ecological differentiation between allopatric clusters of S. hammondii, we recommend that ongoing conservation efforts consider each as a separate unit with potentially unique management needs.


Spea Spadefoot Phylogeography Environmental niche modeling Species delimitation Amphibian conservation 



We thank Robert Fisher, Phil Spinks, and past and present members of the Shaffer Lab for help with field collections and analysis, and the California Department of Fish and Wildlife for permits. Grants from the National Science Foundation (DEB 1257648), US Fish and Wildlife Service (F16PX02290), the Natural Communities Coalition of Orange County (16-12), UCLA Department of Ecology and Evolutionary Biology, UCLA La Kretz Center for California Conservation Science, and Sea and Sage Audubon provided support to KMN and HBS.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflicts of interest.

Supplementary material

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Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Ecology and Evolutionary Biology, La Kretz Center for California Conservation Science, and Institute of the Environment and SustainabilityUniversity of CaliforniaLos AngelesUSA
  2. 2.Department of Ecology and Evolutionary BiologyCornell UniversityIthacaUSA

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