Past, present and future distributions of an Iberian Endemic, Lepus granatensis: ecological and evolutionary clues from species distribution models

Abstract

The application of species distribution models (SDMs) in ecology and conservation biology is increasing and assuming an important role, mainly because they can be used to hindcast past and predict current and future species distributions. However, the accuracy of SDMs depends on the quality of the data and on appropriate theoretical frameworks. In this study, comprehensive data on the current distribution of the Iberian hare (Lepus granatensis) were used to i) determine the species' ecogeographical constraints, ii) hindcast a climatic model for the last glacial maximum (LGM), relating it to inferences derived from molecular studies, and iii) calibrate a model to assess the species future distribution trends (up to 2080). Our results showed that the climatic factor (in its pure effect and when it is combined with the land-cover factor) is the most important descriptor of the current distribution of the Iberian hare. In addition, the model's output was a reliable index of the local probability of species occurrence, which is a valuable tool to guide species management decisions and conservation planning. Climatic potential obtained for the LGM was combined with molecular data and the results suggest that several glacial refugia may have existed for the species within the major Iberian refugium. Finally, a high probability of occurrence of the Iberian hare in the current species range and a northward expansion were predicted for future. Given its current environmental envelope and evolutionary history, we discuss the macroecology of the Iberian hare and its sensitivity to climate change.

Figure 1. Distribution of Lepus sp. in the Iberian Peninsula.

Current distribution of Lepus granantensis represented in UTM 10×10 km – grey – squares. Distribution ranges for sympatric hares species L. castroviejoi (blue triangles) and L. europaeus (red circles) in Spain are also displayed. Data were obtained from Almeida et al. for Portugal and Palomo et al. for Spain. Localities considered in the post-glacial colonization analyses (black circles) are also shown (data obtained from Tables S1 and S2 in Melo-Ferreira et al. [35]).

Figure 2. Cartographic representation of the statistical models.

Probability of Lepus granatensis occurrence in the Iberian Peninsula obtained from the different models (see Table 3). Arrows indicates the transference of the models to the past or future (A2 emissions scenario) time periods. Variation partitioning of the explanatory model is shown in the inset. Values in the diagrams are the percentages of variation in hare presence explained exclusively by topoclimate (TC), land-cover (L), other parapatric Lepus spp. (H) and by the combined effect of these factors.

Figure 3. Calibration assessment of the statistical models.

Calibration plots showing the relationship between the predicted probability of occurrence for the models and the observed proportion of evaluation localities currently occupied by Lepus granatensis: a) explanatory model (see Table 3a), b) model hindcasting to the past (see Table 3b) and c) model to be extrapolated to the future (see Table 3c). Numbers represent the number of evaluation localities in each interval of probability.