To educate a man in mind and not in morals is to educate a menace to society. -Theodore Roosevelt

B&C Fellow - Jami Belt

University of Montana - Masters - Graduated 2010
Evaluating population estimates of mountain goats based on citizen science


Evaluating Population Estimates of Mountain Goats Based on Citizen Science

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 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.

Source: Belt, Jami (2010). Evaluating Population Estimates of Mountain Goats Based on Citizen Science. Master’s thesis, University of Montana.


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