Similar but not equivalent: Ecological niche comparison across closely-related Mexican white pines

Aim: In the face of global environmental change, identifying the factors that shape the ecological niches of species and understanding the mechanisms behind them can help to draft effective conservation plans. The differences in the ecological factors that shape species distributions may then help to highlight differences between closely related taxa. We investigate the applicability of ecological niche modelling and the comparison of species distributions in ecological niche space to detect areas with priority for biodiversity conservation and to analyse differences in the ecological niche spaces used by closely related taxa. Location: United States of America, Mexico and Central America. Methods: We apply ordination and ecological niche modelling techniques to assess the main environmental drivers of the distribution of Mexican white pines (Pinus: Pinaceae). Furthermore, we assess the similarities and differences of the ecological niches occupied by closely related taxa. We analyse whether Mexican white pines occupy similar or equivalent ecological niches. Results: All the studied taxa presented different responses to the environmental factors, resulting in a unique combination of niche conditions. Our stacked habitat suitability maps highlighted regions in southern Mexico and northern Central America as highly suitable for most species and thus with high conservation value. By quantitatively assessing the niche overlap, similarity and equivalency of Mexican white pines, our results prove that the distribution of one species cannot be implied by the distribution of another, even if these taxa are considered closely related. Main conclusions: The fact that each Mexican white pine is constrained by a unique set of environmental conditions, and thus, their non-equivalence of ecological niches has direct implications for conservation as this highlights the inadequacy of one-fits all type of conservation measure. � 2014 The Authors. Diversity and Distributions published by John Wiley & Sons Ltd