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The collapse of cycles in the dynamics of North American grouse populations

In English

Författare

  • C K Williams
  • A R Ives
  • R D Applegate
  • Jörgen Ripa

Summary, in English

Cyclic dynamics of bird and mammal populations are commonly reported in northern latitudes throughout the world, and recent European observations on rodents and grouse suggest that cycle periods decline towards southern latitudes. To investigate latitudinal patterns of cyclic dynamics in North America, we assembled 27 long-term data sets collected between 1939 and 2001 for three grouse species. By fitting the data with autoregressive models to measure direct and delayed density dependence, we show that, in contrast to European studies, North American grouse exhibit period increases from north to south, with cycles collapsing via period lengthening. This occurs because delayed density dependence decreases in southern latitudes, whereas direct density dependence increases. These results show that cyclic dynamics can dissipate by period lengthening as well as the period shortening postulated for European grouse and rodents.

Publiceringsår

2004

Språk

Engelska

Sidor

1135-1142

Publikation/Tidskrift/Serie

Ecology Letters

Volym

7

Issue

12

Dokumenttyp

Artikel i tidskrift

Förlag

Wiley-Blackwell

Ämne

  • Biological Sciences

Status

Published

Forskningsgrupp

  • Theoretical Population Ecology and Evolution Group

ISBN/ISSN/Övrigt

  • ISSN: 1461-023X