Integrating demography and distribution modelling for the iconic Leontopodium alpinum Colm. in the Romanian Carpathians

Both climate change and human exploitation are major threats to plant life
in mountain environments. One species that may be particularly sensitive
to both of these stressors is the iconic alpine flower edelweiss
(Leontopodium alpinum Colm.). Its populations have declined across Europe
due to over-collection for its highly prized flowers. Edelweiss is still
subject to harvesting across the Romanian Carpathians but no study has
measured to what extent populations are vulnerable to anthropogenic
change. Here we estimated the effects of climate and human disturbance on
the fitness of edelweiss. We combined demographic measurements with
predictions of future range distribution under climate change to assess
the viability of populations across Romania. We found that per-capita and
per-area seed number and seed mass were similarly promoted by both
favourable environmental conditions, represented by rugged landscapes with
relatively cold winters and wet summers, and reduced exposure to
harvesting, represented by the distance of plants from hiking trails.
Modelling these responses under future climate scenarios suggested a
slight increase in per-area fitness. However, we found plant ranges
contracted by between 14 to 35% by 2050, with plants pushed into high
elevation sites.  Synthesis. Both total seed number and seed mass
are expected to decline across Romania despite individual edelweiss
fitness benefiting from a warmer and wetter climate. More generally, our
approach of coupling species distribution models with demographic
measurements may better inform conservation strategies of ways to protect
alpine life in a changing world.