Il climate change in the Alps has an important impact on the movements and rhythms of activity of ungulates, raising questions about their future ability to adapt to rising temperatures: this is what emerges from the study published in "Ecology Letters" - one of the most important international journals in the sector - entitled "Behavioral heat-stress compensation in a cold-adapted ungulate: Forage-mediated responses to warming Alpine summers", fruit of the collaboration between the Department of Agronomy, Animals, Food, Natural Resources and Environment of the University of Padua (DAFNAE) and the Department of Biodiversity and Molecular Ecology of the Research and Innovation Center of Edmund Mach Foundation. The research, coordinated by Professor Maurizio Ramanzin of the DAFNAE Department of the University of Padua and by Dr Francesca Cagnacci of the Edmund Mach Foundation, was conducted from 2010 to 2017 in the Marmolada Dolomites area on 24 female ibexes of reproductive age.
For the first time, data from sensors affixed to animals were integrated, however identify their movements and the activity of foraging and resting, remote sensing data, to describe the spatial-temporal variation of the abundance and quality of vegetation, direct observation protocols in the field, to confirm the presence of the kid following the females, and climatological projections to quantify the environmental conditions that the ibex will face in the future. The researchers were thus able to obtain a complete picture of the ecology and behavior of this species depending on environmental factors, but also provide an innovative study perspective that can be applied to other species particularly prone to climate change.
The issue of the impact of global warming on alpine ungulates is much debated in the scientific community. Thanks to the multidisciplinary approach of the research it was possible to model the behavioral adaptations of the ibex to an extreme environment and to provide predictive elements on the risks associated with the inexorable rise in temperatures linked to global warming. "During the winter, the female ibexes remain at relatively low altitudes, around 1700 meters, with very little food activity and travel - he says. Paola Semenzato, who conducted the research during his PhD at the University of Padua - and then considerably increased the time dedicated to feeding in conjunction with the melting of the snow cover and the beginning of vegetational regrowth, which in turn follows the altitudinal gradient.
Thus began a progressive shift towards higher altitudes, up to about 2600-2800 meters reached in the height of summer, to follow this "green wave" (green wave): ibexes - concludes Semenzato - are able to make the most of the 'young' forage and therefore of high nutritional value, which they find as they rise in altitude, compared to what they would find in the wintering areas, where the vegetation it is abundant but 'ages' quickly. In October, with the vegetative stasis even at high altitude and the first snowfalls, there is a gradual descent towards lower altitudes, in the sunny slopes covered by larch woods that offer a certain shelter during the snowy winters of the Dolomites ". The researchers also focused on the daily summer activity rhythms, discovering that the ibex modulate the peaks of food activity according to the temperature: on the hottest days, the animals feed mainly around sunrise and sunset, while they spend the central hours. resting at higher and cooler altitudes.
«The ibex adopts these behavioral adaptations in response to thermal stress as early as 14 ° C, which for the species, particularly adapted to cold climates, represent the threshold of thermal stress - remembers Francesca Cagnacci - By shifting the feeding times, the females are able to keep the daily hours dedicated to food constant. This compensatory capacity was not previously detected by other studies which, not having GPS technology and therefore of the monitoring of the animals, even at night, had hypothesized a negative effect of thermal stress on the daily feeding activity of the ibex. However, it is uncertain whether it will remain effective even in the future. In fact, during our study - underlines Francesca Cagnacci - these temperatures were reached for an average of 16 days during the summer.
According to climatological projections, in a few decades this threshold value will be exceeded for 50 days in the summer period ». According to the climatological scenarios analyzed by the authors, further changes in the activity rhythms of the ibex are therefore foreseeable, which will tend to move more in the night hours, and to try to move higher and higher. "Taken together, these conditions raise various questions about the ability of this and other populations present in the Dolomites area to adapt to progressive global warming - he argues Maurizio Ramanzin -. The upward movement is in fact limited by the typical orography of the Dolomites which are characterized by areas poor in vegetation and rocky walls at relatively low altitudes, unlike the Western Alps, which offer the availability of high altitude meadows where ibex can feed and shelter from the heat at the same time.
In addition, the increasing exposure to days of intense heat could further shift the peaks of foraging activity during the night. In these conditions - concludes Maurizio Ramanzin - the reproductive females, who have the kids in tow, could struggle to move and find the resources they need". According to the researchers, broad-spectrum studies such as these should be conducted on many species present in the Alps that are particularly exposed to rapid climate change, in order to promptly identify the most critical contexts.