Can hunting data be used to estimate unbiased population parameters? A case study on brown bears.
Quantifying temporal changes in harvested populations is critical for applied and fundamental research. Unbiased data are required to detect true changes in phenotypic distribution or population size. Because of the difficulty of collecting detailed individual data from wild populations, data from hunting records are often used. Hunting records, however, may not represent a random sample of a population. We aimed to detect and quantify potential bias in hunting records. We compared data from a long-term monitoring project with hunting records of brown bears (Ursus arctos) in Sweden and investigated temporal trends (1996-2013) in the ratio of yearlings to adult females, yearling mass and adult female mass. Data from hunting records underestimated the decline in yearling and adult female mass over time, most likely owing to the legal protection of family groups from hunting, but reflected changes in the ratio of yearlings to adult females more reliably. Although hunting data can be reliable to approximate population abundance in some circumstances, hunting data can represent a biased sample of a population and should be used with caution in management and conservation decisions.
Département de biologie & Centre for Northern Studies, Université de Sherbrooke, Sherbrooke, Quebec, Canada martin.leclerc2@usherbrooke.ca.
Martin
0000-0002-4429-697X
M
Leclerc
Département de biologie & Centre for Northern Studies, Université de Sherbrooke, Sherbrooke, Quebec, Canada.
Joanie
J
Van de Walle
Department of Environmental and Health Studies, University College of Southeast Norway, Bø, Norway Institute of Wildlife Biology and Game Management, University of Natural Resources and Life Sciences, Vienna, Austria.
Andreas
A
Zedrosser
Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway Norwegian Institute for Nature Research, Trondheim, Norway.
Jon E
JE
Swenson
Département de biologie & Centre for Northern Studies, Université de Sherbrooke, Sherbrooke, Quebec, Canada.
Fanie
F
Pelletier
D000367:Age Factors; D000818:Animals; D001835:Body Weight; D003247:Conservation of Natural Resources; D005260:Female; D011156:Population Density; D013548:Sweden; D001503:Ursidae / Q000502:physiology*
Sweden; Ursus arctos; harvest; hunting regulation; temporal trends