Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2021
Erindi/veggspjald / Talk/poster E37
Höfundar / Authors: Matteo Ferrarini (1), Ólafur Karl Nielsen (2), Mariana Lucia Tamayo (3)
Starfsvettvangur / Affiliations: 1. Master’s Student, Environment and Natural Resources, University of Iceland, 2. Icelandic Institute of Natural History, 3. Environment and Natural Resources, University of Iceland
Kynnir / Presenter: Matteo Ferrarini
The rock ptarmigan (Lagopus muta) is the most important game bird in Iceland and a keystone species within the terrestrial food web; the monitoring of its population is therefore essential to assure a sustainable harvest and a better understanding of trophic interactions. One of the population factors monitored is spring density of territorial cocks; to do so counts of cocks are carried out yearly by the Icelandic Institute of Natural History in different parts of the country. Since 1999, counts have been conducted also on road transects using the distance sampling technique. The goal of this study was to analyse road transect data, collected in 18 counting areas in Iceland from 1999 – 2020, to obtain a population index for the rock ptarmigan and study its population dynamics. The time series of ptarmigan cock density were analysed using autocorrelation, partial autocorrelation, nonlinear time series modelling and cross-correlation analysis. Most of the time series showed signs of cyclicality, with a period between 4 and 14 years, but partial autocorrelation coefficients were significant only in four cases. Four time series showed a positive linear population trend, while one a negative population trend. Synchrony in population changes was common between adjacent areas, while one-year lags were more common at larger distances; significant correlations were rare, and often negative, for lags of more than one year.