Spatial variation in early-winter snow cover determines local dynamics in a network of alpine butterfly populations
Roland, Jens; Matter, Stephen (2020), Spatial variation in early-winter snow cover determines local dynamics in a network of alpine butterfly populations, Dryad, Dataset, https://doi.org/10.5061/dryad.x3ffbg7h8
Snow cover is an extremely variable but critical component of alpine environments. We use long term population data on multiple small populations of the alpine butterfly Parnassius smintheus, combined with high-resolution satellite imagery of meadows, to show a strong link between fine-scale spatial and temporal variation in early-winter snow cover and annual change in butterfly population size, accounting for up to 80 percent of the variation in annual population change. Snow cover in early winter for each meadow is the best predictor of annual adult population change, despite being estimated for a relatively short time-window in late November. We identify a means by which subpopulation response to a local, short-term weather variable can be assessed over a large spatial extent, but also at a resolution relevant to the biology and local dynamics of this alpine species.
List of variables:
meadow identifying letter for the meadow
year year (t) in which population is estimated and weather variables are recorded.
Rt annual rate of population growth in a meadow from year t to year t+1
Nt population size of the meadow in year t
logNt log10 of population size (plus 0.5)* of the meadow in year t
percent percent snow cover in meadow from satellite imagery in November
size size of meadow in hectares
meant mean daily temperature (°C) for the month of November in year t
extmint extreme minimum temperature (°C) in November of year t
extmaxt extreme maximum temperature (°C) in November of year t
*Note: 0.5 was added to population size (Nt) prior to taking the log.
Natural Sciences and Engineering Research Council of Canada
National Science Foundation