Movement and habitat selection of the western spadefoot (Spea hammondii) in southern California

PLoS One. 2019 Oct 3;14(10):e0222532. doi: 10.1371/journal.pone.0222532. eCollection 2019.

Abstract

Agricultural activity, urban development and habitat alteration have caused the disappearance of the western spadefoot (Spea hammondii) from 80% of its geographic range in southern California. Despite the western spadefoot's continuing decline, little research has been conducted on its natural history. The home range of adult spadefoots is unknown, and their use of upland habitat is poorly understood. Both factors are important for the long-term conservation of the species because adult spadefoots spend the majority of their lives away from breeding pools in self-excavated burrows. Between January 2012 and January 2013, we surgically implanted radio transmitters in 15 spadefoots at two locations and recorded their movements and habitat use. The mean distance moved between burrow locations was 18 m (SD ± 24.1 m, range1-204 m). The mean distance of burrows from the breeding pools was 40 m (SD ± 37.42 m, range 1-262 m). Rain was a significant predictor of spadefoot movement, with more rain predicting higher probability of movement and larger distances moved. At remote sensing scale (1 m) spadefoots selected grassland habitat for their burrow locations. At the microsite scale (< 1 m) spadefoots strongly selected duff over grass or shrub cover. Spadefoots burrowed in friable, sandy/loam soil with significantly less clay than random pseudoabsence points. This research enhances our understanding of a little-studied species and will contribute to the development of effective management plans for the western spadefoot.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anura / physiology*
  • Breeding
  • California
  • Ecosystem*
  • Geography
  • Homing Behavior
  • Models, Theoretical
  • Movement*
  • Rain
  • Soil

Substances

  • Soil

Associated data

  • Dryad/10.5061/dryad.8359820

Grants and funding

K. B. received funding from the Laguna Canyon Foundation (https://lagunacanyon.org/), the Association of Zoos and Aquariums Amphibian Taxon Advisory Group Conservation Fund (https://www.aza.org/amphibian-conservation), and the Natural Communities Coalition (formally the Nature Reserve of Orange County) (https://occonservation.org/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.