Priority areas for a cold-adapted snake 341


a change in the thermal landscape will probably reduce the time available for daily activity, which will affect foraging, feeding and breeding success (Walther et al., 2002). For a cold-adapted species such as V. graeca, these changes will have an impact on the persistence of the species as it already occupies a narrow niche in a harsh environment.


Novelties and limitations in estimating land use impact


Our approach involved two rarely used methods. Our layer for habitat degradation characterized grazing pressure by the decrease in phytomass between spring and autumn, which adequately represents grazing pressure in grasslands (Todd et al., 1998; Senay & Elliott, 2000; Kawamura et al., 2005). We developed this further by spatial interpolation of the distribution of livestock folds weighted by phytomass decrease, which is a novel approach to estimating the inten- sity of land use or the degree of disturbance. Further studies are needed to calibrate this type of derived variable accurate- ly with on-site measurements or experiments. One potential limitation of our study is that land-use in-


tensity is probably higher at the lower elevations ofV. graeca habitats (1,500–1,800 m) than at higher elevations. Lower elevations are easier to access for people and grazing live- stock, snow melts are earlier, and thus the grazing season is longer than at higher elevations. Therefore it is possible that V. graeca may already have disappeared from lower ele- vations as a result of anthropogenic impacts, and that our suitability models based on current conditions are biased to colder climates and/or higher elevations. This is unlike- ly, however, because lower elevations are often secondary grasslands established in previously wooded areas below the former treeline, as evidenced by wooded areas remain- ing on slopes too steep for grazing livestock (Fig. 5). It is therefore unlikely that these lower elevation areas were for- merly suitable for V. graeca.Moreover, overgrazing also oc- curs at higher elevations, where the species is present, albeit in lower abundance. Nevertheless, because the species was discovered only in the 1980s there are no historical data to test temporal patterns in habitat occupancy.


Prioritization for single species


Systematic conservation planning techniques were devel- oped for multiple species (Lehtomäki & Moilanen, 2013)and have only recently been applied for single species (Adam- Hosking et al., 2015). Single species conservation planning follows the same protocol but ranks sites according to the spatial distribution of threat factors (or conservation value), and/or the cost of protection (Adams-Hosking et al., 2015; Nori et al., 2016). The scarcity of systematic conservation planning for single species is probably a result of the primary importance of biodiversity protection as opposed


to species protection. Our study shows that the approach can provide information of value for the conservation of umbrella, flagship or keystone species.


Recommendations for the conservation of V. graeca


Our study shows that V. graeca habitats may face significant losses or further fragmentation up to 2089, although some populations in a few contiguous habitats are predicted to persist. These results suggest that conservation should focus on sites of high importance by improving habitat quality, reducing disturbance and degradation, effectively protecting the species, educating local stakeholders and continuing to monitor the populations. Raising awareness and involvement of local communities


is central to any conservation action, to ensure its success, and to establish sustainable land use (Adele et al., 2015). Research by the Greek Meadow Viper Working Group on human– wildlife conflict resulting from sheep mortality as a result of snake bites is already underway and is trying to identify ways to involve local communities.This project has already recom- mended that shepherds followtwo guidelines for grazing live- stock in V. graeca habitats: avoid grazing on south-eastern slopes where vipers are more abundant, or, if the shepherd must utilize these slopes, do so between 11.00–15.00,when vipers usually shelter from the midday heat. Our findings warrant slightly different recommendations


for sustainable land use in the two countries. In Albania grazing pressure needs to be reduced to achieve an im- proved, more natural vegetation structure in meadows. In Greece a shift from cattle grazing to sheep grazing is re- quired. Cattle grazing has a stronger and more negative im- pact because cattle uproot vegetation, which is detrimental to both the top soil layer and vegetation. Eradication of fescue tussocks (Fig. 5) has already changed the vegetation, resulting in the homogenization of microhabitats: there are fewer structures that provide shelter and shade for snakes, which in turn increases predation by birds of prey and reduces the abundance of the viper’s Orthopteran prey (Lemonnier-Darcemont et al., 2018). Along with habitat conservation, we recommend the


launch of an ex situ breeding programme, similar to that for the threatened Hungarian meadow viper Vipera ursinii rakosiensis (Péchy et al., 2015), to help reinforce populations that are suffering from the symptoms of an extinction vor- tex. We suggest that a combination of ex situ and in situ conservation plans and continued research on the ecology and population genetics of V. graeca in high priority areas are necessary to ensure persistence. Further research, in conjunction with local and governmental support, is key for the development of a species conservation programme that will ensure the long-term survival of this Endangered, cold-adapted species trapped on mountaintops in the warm- ing Mediterranean basin.


Oryx, 2021, 55(3), 334–343 © The Author(s), 2020. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605319000322


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