corresponding mitochondrial dna and niche divergence for crested newt candidate species相应的线粒体dna和小众冠候选人纽特物种的差异.pdf

Corresponding Mitochondrial DNA and Niche Divergence for Crested Newt Candidate Species 1,2 2 1 2 2 Ben Wielstra *, Wouter Beukema , Jan W. Arntzen , Andrew K. Skidmore , Albertus G. Toxopeus , Niels Raes1 1 Naturalis Biodiversity Center, Leiden, The Netherlands, 2 University of Twente, Faculty of Geo-Information Science and Earth Observation – ITC, Enschede, The Netherlands Abstract Genetic divergence of mitochondrial DNA does not necessarily correspond to reproductive isolation. However, if mitochondrial DNA lineages occupy separate segments of environmental space, this supports the notion of their evolutionary independence. We explore niche differentiation among three candidate species of crested newt (characterized by distinct mitochondrial DNA lineages) and interpret the results in the light of differences observed for recognized crested newt species. We quantify niche differences among all crested newt (candidate) species and test hypotheses regarding niche evolution, employing two ordination techniques (PCA-env and ENFA). Niche equivalency is rejected: all (candidate) species are found to occupy significantly different segments of environmental space. Furthermore, niche overlap values for the three candidate species are not significantly higher than those for the recognized species. As the three candidate crested newt species are, not only in terms of mitochondrial DNA genetic divergence, but also ecologically speaking, as diverged as the recognized crested newt species, our findings are in line with the hypothesis that they represent cryptic species. We address potential pitfalls of ou