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Title page for ETD etd-01222011-134220


Type of Document Master's Thesis
Author Belt, Jami J
Author's Email Address jami_belt@nps.gov
URN etd-01222011-134220
Title Evaluating population estimates of mountain goats based on citizen science
Degree Master of Science
Department Wildlife Biology
Advisory Committee
Advisor Name Title
Paul R. Krausman Committee Chair
Joel Berger Committee Member
Mike Mitchell Committee Member
Keywords
  • population estimates
  • Oreamnos americanus
  • mountain goats
  • citizen science
  • volunteers
  • Glacier Naitonal Park
  • distribution
Date of Defense 2010-09-21
Availability unrestricted
Abstract
Citizen science programs that use trained volunteers may be a cost-effective

method for monitoring wildlife at large spatial and temporal scales. However, few studies

have compared inferences made from data collected by volunteers to professionally

collected data. In Glacier National Park (GNP), Montana, I assessed whether citizen

science is a useful method to monitor mountain goat (Oreamnos americanus)

populations. I compared estimates of mountain goat abundance by volunteers at 32 sites

throughout GNP to estimates by biologists and raw counts from aerial surveys at a subset

of 25 and 11 sites, respectively. I used multiple observer surveys to calibrate the indices

of abundance for the effect of observer variation between volunteers and biologists. I

used N-mixture models, which calculated detection probability through patterns of

detection and non-detection to obtain estimates of abundance. Population estimates made

by citizen science overlapped estimates by biologists and estimates from previous

research. Density estimates from aerial surveys were lower, possibly due to imperfect

detection during aerial surveys or due to violation of the assumption of population

closure. Mean detection probability from multiple observer surveys for biologists was

significantly higher and less variable than that of volunteers, but was not a suitable

correction factor, because it was not consistent across all densities of mountain goats.

Volunteer experience did not significantly influence detection probability or abundance

estimates. Abundance estimates by volunteers were influenced by number of site visits.

More frequent site visits balanced out lower detection probability by volunteers and

resulted in abundance estimates that were less variable than those of biologists. When

large spatial and temporal coverage can be achieved, citizen science can provide

mountain goat population estimates that are statistically similar to those of biologists.

However, neither estimates by volunteers or biologists had sufficient statistical power to

detect a 30% decline in mountain goat population size over 10 years. Power by

volunteers could be increased by reducing the number of sites and increasing surveys/site

or by continuing monitoring over a longer time frame (i.e., 30 years). Citizen science

programs can contribute to long term monitoring when properly designed.

Files
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