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Evaluating Growth of the Porcupine Caribou Herd Using a Stochastic Model
- Source :
- The Journal of Wildlife Management. 59:262
- Publication Year :
- 1995
- Publisher :
- JSTOR, 1995.
-
Abstract
- Estimates of the relative effects of demographic parameters on population rates of change, and of the level of natural variation in these parameters, are necessary to address potential effects of perturbations on populations. We used a stochastic model, based on survival and reproduction estimates of the Porcupine Caribou (Rangifer tarandus granti) Herd (PCH), during 1983-89 and 1989-92 to obtain distributions potential population rates of change (r). The distribution of r produced by 1,000 trajectories of our simulation model (1983-89, r = 0.013; 1989-92, r = 0.003) encompassed the rate of increase calculated from an independent series of photo-survey data over the same years (1983-89, r = 0.048; 1989-92, r = −0.035). Changes in adult female survival had the largest effect on r, followed by changes in calf survival. We hypothesized that petroleum development on calving grounds, or changes in calving and post-calving habitats due to global climate change, would affect model input parameters. A decline in annual adult female survival from 0.871 to 0.847, or a decline in annual calf survival from 0.518 to 0.472, would be sufficient to cause a declining population, if all other input estimates remained the same. We then used these lower survival rates, in conjunction with our estimated amount of among-year variation, to determine a range of resulting population trajectories. Stochastic models can be used to better understand dynamics of populations, optimize sampling investment, and evaluate potential effects of various factors on population growth
- Subjects :
- education.field_of_study
Porcupine caribou
Ecology
Stochastic modelling
media_common.quotation_subject
Population
Ice calving
Biology
biology.organism_classification
Rangifer tarandus granti
Statistics
Herd
General Earth and Planetary Sciences
Population growth
Reproduction
education
Ecology, Evolution, Behavior and Systematics
Nature and Landscape Conservation
General Environmental Science
media_common
Subjects
Details
- ISSN :
- 0022541X
- Volume :
- 59
- Database :
- OpenAIRE
- Journal :
- The Journal of Wildlife Management
- Accession number :
- edsair.doi...........5ebd1c580adb75b7422eeb356ba2121e