Variations in lamb growth on coastal and mountain pastures, will climate change make a difference?

Lamb Performance on Island Pastures in Northern Norway

The Norwegian sheep industry is based on utilization of "free" rangeland pasture resources. Use of mountain pastures is dominating, with about two million sheep grazing these pastures during summer. Regional challenges related to e.g., loss of sheep to large carnivores make farmers think differently. The Norwegian coastline is among the longest globally and is scattered with islets and islands. Alone along the coast of Nordland county, it is estimated more than 14,000 islands. Use of islands for summer pasture is an alternative but there is a limited knowledge about such a management system. In this study, we examined lambs' average daily gain on island pastures at the coast of Norway. In total 230 lambs on three islands (Sandvær, Sjonøya, and Buøya), with varying pasture quality and stocking rate, for 3 years (2012, 2013, and 2014). At Sandvær as much as 92% of the island was characterized as high nutritional value while at Sjonøya and Buøya only 15%, was characterized high nutritional value. We found an average daily lamb growth rate of 0.320 kg d^-1. Lambs on Sandvær had a higher daily gain (P < 0.05) than those on Sjonøya and Buøya, and lambs' average daily gain was significantly lower (P < 0.05) in 2013 compared to 2012 and 2014. We conclude that with a dynamic and adaptive management strategy there is a potential to utilize islands for sheep grazing during summer.

When does weather synchronize life-history traits? Spatiotemporal patterns in juvenile body mass of two ungulates

Theory predicts that animal populations will be synchronized over large distances by weather and climatic conditions with high spatial synchrony. However, local variation in population responses to weather, and low synchrony in key weather variables or in other ecological processes may reduce the population synchrony. We investigated to what extent temperature and precipitation during different periods of the year synchronized juvenile body mass of moose and reindeer in Norway. We expected high synchronizing effect of weather variables with a high and consistent explanatory power on body mass dynamics across populations, and a weaker synchronizing effect of weather variables whose effect on body mass varied among populations. Juvenile body mass in both species was related to temperature and precipitation during several periods of the year. Temperature had the strongest explanatory power in both species, with a similar effect across all populations. There was higher spatial synchrony in temperature compared to precipitation, and accordingly temperature had the strongest synchronizing effect on juvenile body mass. Moreover, periods with strong explanatory power had stronger synchronizing effect on juvenile body mass in both species. However, weather variables with large variation in the effects on body mass among populations had weak synchronizing effect. The results confirm that weather has a large impact on the spatial structure of population properties but also that spatial heterogeneity, for instance, in environmental change or population density may affect how and to what extent populations are synchronized.