Do protected areas represent species’ optimal climatic conditions? A test using Iberian water beetles

Abstract

Aim To assess the effectiveness of protected area networks in representing the climatic niche of Iberian water beetle species.Location Iberian Peninsula. Methods We used distribution data from 133 endemic water beetle species in the Iberian Peninsula. Climatic potential distributions were estimated by applying a multidimensional-envelope procedure based on climatic data (both current and future) and observed occurrences. Mahalanobis distances were calculated to obtain continuous climatic suitability values within the climatic potential distribution. Two protected area networks were assessed: National Parks (NPs) and Natura 2000 (N2000). The average climatic suitability value for the cells overlapping with protected areas was calculated and compared with the average value of 10,000 random samples from the same number of cells within their entire potential distribution, which allowed to identify species whose climatic niches were optimally or marginally represented. Results Fifty-seven and 104 of the 107 considered taxa were represented with at least one occurrence in NPs and N2000, respectively, and the climatic potential distributions of 93 and all 107 taxa overlapped with NPs and N2000. While the climatic niches of 48 and 38 taxa were marginally represented in NPs and N2000, the climatic niches of only 11 and 29 were optimally represented by these two protected area networks. When predicted future climatic conditions were considered, both the climatic suitability values and the number of species whose potential distribution was represented by protected areas decreased. Main conclusions Although the representation of endemic Iberian taxa could be considered adequate, these results show that for most of them the protected networks tend to include areas with climatic conditions close to the species tolerance limit, and the expected climate change only worsened this scenario. Thus, current protected areas cannot be considered to guarantee the long-term survival of the species considered in this study.