Climate Change and Human Disturbance Can Lead to Local Extinction of Alpine Rock Ptarmigan: New Insight from the Western Italian Alps

Abstract

Alpine grouses are particularly vulnerable to climate change due to their adaptation to extreme conditions and to their relict distributions in the Alps where global warming has been particularly marked in the last half century. Grouses are also currently threatened by habitat modification and human disturbance, and an assessment of the impact of multiple stressors is needed to predict the fate of Alpine populations of these birds in the next decades. We estimated the effect of climate change and human disturbance on a rock ptarmigan population living in the western Italian Alps by combining an empirical population modelling approach and stochastic simulations of the population dynamics under the a1B climate scenario and two different disturbance scenarios, represented by the development of a ski resort, through 2050.The early appearance of snow-free ground in the previous spring had a favorable effect on the rock ptarmigan population, probably through a higher reproductive success. On the contrary, delayed snowfall in autumn had a negative effect possibly due to a mismatch in time to molt to white winter plumage which increases predation risk. The regional climate model PROTHEUS does not foresee any significant change in snowmelt date in the study area, while the start date of continuous snow cover is expected to be significantly delayed. The net effect in the stochastic projections is a more or less pronounced (depending on the model used) decline in the studied population. The addition of extra-mortality due to collision with ski-lift wires led the population to fatal consequences in most projections. Should these results be confirmed by larger studies the conservation of Alpine populations would deserve more attention. To counterbalance the effects of climate change, the reduction of all causes of death should be pursued, through a strict preservation of the habitats in the present area of occurrence.

No short-term effects of climate change on the breeding of Rock Ptarmigan in the French Alps and Pyrenees

“…At all sites, reproductive success was much lower when the snowmelt date was later and the rainfall after hatching was high. The negative effect of a late snowmelt on the reproductive success of the Rock Ptarmigan has been previously reported for the Canigou Massif (Novoa et al 2008), and more recently Imperio et al (2013) found that the early appearance of snow-free ground the previous spring had a favourable effect on Rock Ptarmigan numbers the following year, probably because of higher reproductive success. The fact that our study was carried out at three different sites both in the Alps and the Pyrenees gives stronger support to the relationship between breeding success, snowmelt date and rainfall after hatching.…”

“…Like other cold-adapted species, the Rock Ptarmigan is regularly cited as a potential sentinel species for indicating the effects of climate change, especially in its southernmost habitats (Revermann et al 2012;Imperio et al 2013). Negative trends in Rock Ptarmigan numbers have been recently attributed to climate change both in the Swiss (Revermann et al 2012) and Italian (Imperio et al 2013) Alps.…”

“…Negative trends in Rock Ptarmigan numbers have been recently attributed to climate change both in the Swiss (Revermann et al 2012) and Italian (Imperio et al 2013) Alps. In France, studies that monitor Rock Ptarmigan populations also suggest a decrease of the species both in the Alps and the Pyrenees, particularly at the margins of the distribution range (Ellison et al 2003;Buffet et al 2011).…”

Microclimate and microhabitat selection by the Alpine Rock Ptarmigan (Lagopus muta helvetica) during summer

“…The prediction of a shrinking area for the Alpine Rock Ptarmigan with climate warming derives mainly from the paramount importance of the mean July temperature and other variables related to low temperatures (e.g., typical snow-bed vegetation) when modeling the distribution at the mesoscale and macroscale (Revermann et al 2012;Imperio et al 2013).…”

Animal coloration research: why it matters

“…Many other environmental changes are occurring. For example, as mangrove acreage declines with sea-level rise, changes in colour frequencies can be expected in Bornean gliding lizards Draco cornutus that match the colours of freshly fallen leaves in either mangroves or rainforest [85]; and as snow cover declines with global warming, populations of Alpine rock ptarmigan Lagopus muta and snowshoe hares Lepus americanus will dwindle [86,87]. In aquatic environments, where particulate matter in water absorbs short wavelengths causing a shift towards orange and red, similar evolutionary colour changes can be expected.…”