Survey method choice for wildlife management: The case of moose Alces alces in Sweden

Månsson, Johan, Hauser, Cindy E., Andrén, Henrik and Possingham, Hugh P. (2011) Survey method choice for wildlife management: The case of moose Alces alces in Sweden. Wildlife Biology, 17 2: 176-190. doi:10.2981/10-052

Author Månsson, Johan
Hauser, Cindy E.
Andrén, Henrik
Possingham, Hugh P.
Title Survey method choice for wildlife management: The case of moose Alces alces in Sweden
Formatted title
Survey method choice for wildlife management: The case of moose Alces alces in Sweden
Journal name Wildlife Biology   Check publisher's open access policy
ISSN 0761-9243
Publication date 2011-06-01
Sub-type Article (original research)
DOI 10.2981/10-052
Open Access Status DOI
Volume 17
Issue 2
Start page 176
End page 190
Total pages 15
Editor Stefano Focardi
Place of publication Hornslet, Denmark
Publisher Nordisk Kollegium for Vildtforskning
Language eng
Formatted abstract
We need to monitor wildlife populations to determine whether management goals are achieved and to improve future decisions. Therefore, it is important to evaluate the cost and accuracy of monitoring strategies in the context of management. Using a computer simulation of a harvested population, we tested the relative performance of three survey methods: aerial survey, pellet-group counts and hunters' observations, to inform about the management of Swedish moose Alces alces populations. Where more than one survey method was used in a single year, we used Bayes' theorem to combine information and estimate population size. We used two measures of performance: the fraction of time in which the population had an ‘undesirable’ size and inter-annual variation in harvest. Furthermore, we traded these performance measures against their cost. An annual aerial survey was the most costly monitoring method (27,000€) and maintained the population within the desired range 72% of the time. The least expensive monitoring strategy (hunters' observations; 1,600€) maintained the population within a desired range of 66% of the time. A combination of two relatively inexpensive survey methods (i.e. pellet-group counts and hunters' observations; at an expense of 10,000€) maintained the population within the desired range in 76% of the simulated years. Thus, a combination of annual pellet-group counts and hunters' observations performed better than annual aerial surveys, but was considerably less expensive. Furthermore, the annual combination of pellet-group counts and hunters' observations also performed best regarding the inter-annual harvest variation. Management actions only maintained the population within the desired range 81% of the time, even when population size was observed without error, mainly due to variable net growth rates. In wildlife management systems, where a variety of monitoring methods are used, the overall performance generally improves with monitoring expenditure, but very few studies explicitly account for expenditure. However, our study shows that combinations of inexpensive methods can reduce monitoring costs substantially while yielding an equal or an increased performance.
Keyword Aerial counts
Bayesian updating
Direct observations
Pellet-group counts
Large herbivores
Hunter observations
Deer population
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
School of Agriculture and Food Sciences
Ecology Centre Publications
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