1. Identifying those areas suitable for recolonization by threatened species is essential to support efficient conservation policies. Habitat suitability models (HSM) predict species’ potential distributions, but the quality of their predictions should be carefully assessed when the species-environment equilibrium assumption is violated. 2. We studied the Eurasian otter Lutra lutra, whose numbers are recovering in southern Italy. To produce widely applicable results, we chose standard HSM procedures and looked for the models’ capacities in predicting the suitability of a recolonization area. We used two fieldwork datasets: presence-only data, used in the Ecological Niche Factor Analyses (ENFA), and presence-absence data, used in a Generalized Linear Model (GLM). In addition to cross-validation, we independently evaluated the models with data from a recolonization event, providing presences on a previously unoccupied river. 3. Three of the models successfully predicted the suitability of the recolonization area, but the GLM built with data before the recolonization disagreed with these predictions, missing the recolonized river’s suitability and badly describing the otter’s niche. Our results highlighted three points of relevance to modelling practices: (1) absences may prevent the models from correctly identifying areas suitable for a species spread; (2) the selection of variables may lead to randomness in the predictions; and (3) the Area Under Curve (AUC), a commonly used validation index, was not well suited to the evaluation of model quality, whereas the Boyce Index (CBI), based on presence data only, better highlighted the models’ fit to the recolonization observations. 4. For species with unstable spatial distributions, presence-only models may work better than presence-absence methods in making reliable predictions of suitable areas for expansion. An iterative modelling process, using new occurrences from each step of the species spread, may also help in progressively reducing errors. 5. Synthesis and applications. Conservation plans depend on reliable models of the species’ suitable habitats. In non-equilibrium situations, such as the case for threatened or invasive species, models could be affected negatively by the inclusion of absence data when predicting the areas of potential expansion. Presence-only methods will here provide a better basis for productive conservation management practices.

This paper defines a protocol for the study of leaf morphology and morphometric relationships among Quercus frainetto, Quercus robur, Quercus petraea and Quercus pubescens. Leaf shapes were investigated in an attempt to characterize and discriminate among these four species. Landmark and outline data were compared in order to ascertain their relative efficacy for describing variation in leaf morphology. MANOVA was performed to assess intra‐specific differentiation and to compare the distribution of variance in individuals, populations and species. A strong correlation was found between landmark and outline datasets of the four species: both methods proved capable of discriminating among the four species. Finally, a Two‐Block Partial Least‐Squares analysis was performed for each species in order to assess the correlation between intra‐specific shape variation and environmental factors.

Molecular studies highlighted a strong genetic affinity between the remnant and isolated population of the Apennine brown bear and other southern Euro

The geographic variation of seven southern European populations of Ursus arctos was investigated through multivariate morphometrics of the skull. Univariate and multivariate analyses were run on 63 cranial and dental measurements recorded on 50 specimens from the Apennines, the Alps, and the Transcaucasus, and on 14 specimens of the fossil Ursus spelaeus. Detailed analyses of sexual dimorphism, age structure, and ranges of variation have been carried out on the Apennines population, which morphological variation has been little explored. Subsets of characters were selected to allow comparison with data derived from literature for populations from the Pyrenees, the Rhodopi‐Rila‐Pirin, the Balkans, and the Caucasus. Analyses clearly indicate that the Apennine bear is morphologically distinct from both a western (Alps, Pyrenees, Balkans, and Rhodopi) and an eastern contingent (Caucasus and Transcaucasus), therefore suggesting that the Apennine population should be reconsidered as a separate taxon, namely Ursus arctos marsicanus. These preliminary results suggest caution in restocking conservation actions.