Abstract
Local adaptation to annually changing environments has evolved in
numerous species. Seasonal coat colour change is an adaptation that has
evolved in multiple mammal and bird species occupying areas that
experience seasonal snow cover. It has a critical impact on fitness as
predation risk may increase when an individual is mismatched against its
habitat’s background colour. In this paper we investigate the impact of
landscape covariates on moult timing in a native winter-adapted
herbivore, the mountain hare (Lepus timidus), throughout Norway.
Data was collected between 2011 and 2019 at 678 camera trap locations
deployed across an environmental gradient. Based on this data, we
created a Bayesian multinomial logistic regression model that quantified
the correlations between landscape covariates and coat colour phenology
and analysed among season and year moult timing variation. Our results
demonstrate that mountain hare moult timing is strongly correlated with
altitude and latitude with hares that live at higher latitudes and
altitudes keeping their winter white coats for longer than their
conspecifics that inhabit lower latitudes and altitudes. Moult timing
was also weakly correlated with climate zone with hares that live in
coastal climates keeping their winter white coats for longer than hares
that live in continental climates. We found evidence of some among year
moult timing variation in spring, but not in autumn. We conclude that
mountain hare moult timing has adapted to local environmental conditions
throughout Norway.