Are the declining trends in forest grouse populations due to changes in the forest age structure? A case study of Capercaillie in Finland

Abstract

In Finland, Capercaillie (Tetrao urogallus) populations have a history of serious decrease starting from the mid-20th century. The decline is temporally in line with the expansion of modern forestry practices that created major changes in the landscape. We used tetraonid route-censuses from 18 forestry board districts and Finnish forest inventories (data on forest stand structure) to analyze the decline in 1965-1988. We used information theoretical model selection to evaluate a set of log-linear second order auto-regressive models, allowing for spatially correlated process errors. The average trend throughout the country corresponded to an annual decline of 4.01% (mean of local trends) +/- 0.24% (SEM), parallel to a half-life of 17 years. The decline was surprisingly uniform throughout the country (SD = 1.01%) and most parsimoniously explained by a geographically constant log-linear trend. At the large scale of observation applied here, population trends could not be explained by the proportional increase of younger forest age classes (

Keywords

Forestry; Grouse; Spatial population dynamics; Tetrao urogallus; Time series analysis

Published in

Biological Conservation
2010, volume: 143, number: 6, pages: 1540-1548
Publisher: ELSEVIER SCI LTD

SLU Authors

• Knape, Jonas

  • University of California Berkeley

UKÄ Subject classification

Ecology

Publication identifier

• DOI: https://doi.org/10.1016/j.biocon.2010.03.038

Permanent link to this page (URI)

https://res.slu.se/id/publ/86374