Parasites and climate synchronize red grouse populations

Area of Science:

• Ecology
• Population Dynamics
• Parasitology

Background:

• Correlated climatic conditions may synchronize animal population fluctuations.
• The direct or indirect effects of climate on population dynamics are not fully understood.
• Climate's role in trophic interactions as a synchronizing mechanism requires investigation.

Purpose of the Study:

• To investigate the mechanism by which climate synchronizes spatially distributed animal populations.
• To determine if climate directly impacts individual survival/fecundity or indirectly via food/enemies.
• To explore climate's effect on trophic interactions and parasite transmission.

Main Methods:

• Analysis of red grouse population dynamics in northern England.
• Correlation of population fluctuations with climatic conditions in May and July.
• Investigation of the influence of climate on the transmission of the parasite Trichostrongylus tenuis.

Main Results:

• Red grouse populations in northern England exhibited synchronous increases and decreases in specific years.
• Widespread, correlated climatic conditions during May and July were linked to these synchronous fluctuations.
• Climate influenced the density-dependent transmission of the gastrointestinal nematode Trichostrongylus tenuis, affecting grouse fecundity.

Conclusions:

• Climate affects trophic interactions, serving as a mechanism for synchronizing populations.
• Specific climatic events can lead to infectious disease outbreaks, causing synchronized host population changes.
• The parasite Trichostrongylus tenuis plays a key role in mediating climate-induced synchrony in red grouse populations.