Nicole Hoyt and Dr' John Cossel Jr' Department of Biology

1
Nicole Hoyt and Dr. John Cossel Jr. -
Department of Biology
Assessing the Impact of Surface Mining on a
Sensitive Species of Lizard (Crotaphytus
bicinctores) Using Measures of Home Range and
Population Density
Abstract
Materials Methods

• Density was determined using areas from MCPs
  generated for all spatial points of lizards at
  particular sites.

• Our study area was located in Owyhee county,
  Idaho and consisted of 275 hectares. The area
  has scattered ridges and buttes with rock
  outcroppings and a desert shrub community.
• We acquired spatial data using radio telemetry.
  Transmitters were manufactured by Holohil Systems
  Ltd. and weighed 2g. Transmitters were
  attached using thin elastic cording looped over
  each hind limb and crisscrossed on the ventral
  surface. The cording was knotted and super
  glued.
• A 150 -151 MHz receiver (Wildlife Materials
  Inc.) and a folding 3 element hand-held antennae
  were used to locate lizards.
• When acquiring spatial data, individuals were
  located 1-3 times per day.
• A global positioning positing system (GPS) with
  submeter accuracy (GeoExplorer XT) was used to
  obtain universal transmercator (UTM) coordinates.
• Spatial data were imported into a geographical
  information system (GIS). Using Arcview 3.2 and
  the Animal Movement Module v. 2.04 (Hooge and
  Eichenlaub, 1997)), we determined lizard home
  ranges.
• Home range was modeled by determining 95
  minimum convex polygons (95MCP) and Fixed Kernel
  contours at 95 probability.

Surface mining has occurred at a site where the
sensitive species the Great Basin Collared Lizard
(Crotaphytus bicinctores) exists. We assessed
potential impacts of mining on this saxicolous
species by determining lizard home range and
density at mined and unmined sites. We found
that lizard density was greatest at unmined
sites, while male home range size appeared larger
where mining had occurred. Our results may have
implications for proposed future mining activity.
Results

• Males had larger home ranges than females.
  Males appeared to have larger home range size at
  mined sites.
• It appeared that a larger number of lizards
  occurred at unmined sites versus areas at which
  mining occurred at or near the site.

Introduction
Figure 4. Home range size (95MCP) of male and
female Great Basin Collared Lizards at mined and
unmined sites.

• Land managers are faced with the challenge of
  managing resource use while maintaining
  biodiversity. However, little information exists
  on the impacts of some types of resource
  extraction.
• Surface mining which has recently increased to
  meet demands of construction and landscaping, has
  occurred at a site where the sensitive species C.
  bicinctores exists.
• A study in Australia found that rock removal
  degraded habitat of a saxicolous lizard and other
  rock inhabiting species as well (Schlesinger and
  Shine 1994).
• Similarly, Pope and Munger (2003) suggested that
  rock removal may have a negative impact on C.
  bicinctores (Pope and Munger 2003). However, to
  our knowledge, no published data are available on
  the effects of rock removal on this species.
• Our objectives were to assess potential impacts
  of surface mining on C. bicinctores by

Figure 2. Radio transmitter attachment on Great
Basin Collared Lizards, dorsal and ventral views.
(n2)
(n1)
Density (lizards/hectare)
(n1)
Figure 5. Great Basin Collared Lizard density at
unmined, mixed and mined sites.
Summary

• Our study suggests that mining may have an
  impact on the Great Basin Collard Lizard, as
  evidenced by lower population density and larger
  home range size where mining activity has
  occurred.
• This study will also provide baseline data for
  comparing home range changes after additional
  mining occurs.

Figure 1. Surface mining at our study area in
southwestern Idaho.
Literature Cited
Hooge, P., and W. M. Eichenlaub. 1997. Animal
Movement extension to Arcview ver. 2.04. Alaska
Biological Science Center, US Geological Survey,
Anchorage, AK, USA. Pope, V. and J. C. Munger.
2003. Threats to Collared Lizards in Idaho. BLM
Tech. Bull. No. 03-4. 12pp. Schlesinger C. A.,
R. Shine. 1994. Choosing a rock perspectives of
a bush-rock collector and a saxicolous lizard.
Biological Conservation 6749-56.

• Acknowledgements
• M. J. Murdock Charitable Trust Fund
• Northwest Nazarene University
• Idaho Department of Fish and Game

Figure 3. Distribution of C. bicinctores 95
minimum convex polygon home ranges at our study
site in southwestern Idaho .