Can parasites synchronise the population fluctuations of sympatric tetraonids? -examining some minimum conditions

• Published in: Oikos Vol. 109; no. 3; pp. 429 - 434
• Main Authors: Holmstad, Per R., Hudson, Peter J., Vandvik, Vigdis, Skorping, Arne
• Format: Journal Article
• Language: English
• Published: Copenhagen Munksgaard International Publishers 01-06-2005; Blackwell Publishers; Blackwell; Blackwell Publishing Ltd
• Subjects: Animal and plant ecology; Animal populations; Animal, plant and microbial ecology; Aves; Biological and medical sciences; Birds; Fjords; Fundamental and applied biological sciences. Psychology; General aspects; Geodetic position; Grouse; Hunting; Parasite hosts; Parasites; Population density; Population dynamics; Sympatric species; Parasite; Sympatry; Fluctuations; Geographic distribution
• ISSN: 0030-1299; 1600-0706
• DOI: 10.1111/j.0030-1299.2005.13702.x

Sympatric populations of tetraonid birds tend to fluctuate in synchrony, at least on local scales. If shared parasites among sympatric populations of different tetraonid species are to operate as a local, synchronizing factor for population fluctuations at least two conditions should be met: i) the host species should share the same (or similar) parasite species, and ii) geographical location should contribute significantly more to the variation in the parasite species composition and abundance than differences among host species. We examined these conditions among subpopulations of sympatric willow ptarmigan and rock ptarmigan and found that host species shared a common pool of parasite species, and geographic location was more important than host species in determining parasite abundance across locations. There was no time lag between density oscillations in the two hosts, suggesting a symmetrical pattern of transmission and maintenance of parasites within habitats governed by the density of hosts and the environment. These findings are consistent with the idea that parasites may play a role in generating synchronous density fluctuations, but large scale experiments are needed to verify this hypothesis.