Little hope for the polyploid endemic Pyrenean Larkspur (Delphinium montanum): evidences from population genomics and Ecological Niche Modelling

Species endemic to restricted geographical ranges represent a particular conservation issue, be it for their heritage interest. In a context of global change, this is particularly the case for plants which belong to high-mountain ecosystems and, because of their ecological requirements, are doomed to survive or disappear on their "sky islands". The Pyrenean Larkspur (Delphinium montanum, Ranunculaceae) is endemic to the Eastern part of the Pyrenees (France and Spain). It is now only observable at a dozen of localities and some populations show signs of decline, such as a recurrent lack of flowering. Implementing population genomic approach (e.g. RAD-seq like) is particularly useful to understand genomic patterns of diversity and differentiation in order to provide recommendations in term of conservation. However, it remains challenging for species such as D. montanum that are autotetraploid with a large genome size (1C-value > 10 pg) as most methods currently available were developed for diploid species. A Bayesian framework able to call genotypes with uncertainty allowed us to assess genetic diversity and population structure in this system. Our results show evidence for inbreeding (mean GIS = 0.361) within all the populations and substantial population structure (mean GST = 0.403) at the metapopulation level. In addition to a lack of connectivity between populations, spatial projections of Ecological Niche Modelling analyses under different climatic scenarios predict a dramatic decrease of suitable habitat for D. montanum in the future. Based on these results, we discuss the relevance and feasibility of different conservation measures.

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Climate and Competition Shape Species' Borders: A Study of the Panamint (Crotalus stephensi) and Speckled (Crotalus mitchellii) Rattlesnakes

ISRN Zoology ◽

10.5402/2012/528745 ◽

2012 ◽

Vol 2012 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

A. Michelle Lawing ◽

Jesse M. Meik ◽

P. David Polly

Keyword(s):

Ecological Niche ◽

Climatic Factors ◽

Interspecific Interactions ◽

Ecological Niche Modelling ◽

Suitable Habitat ◽

Niche Modelling ◽

Closely Related Species ◽

Crotalus Mitchellii ◽

Suitable Habitats ◽

The Last Glacial

We used ecological niche modelling to study the relative roles of climate and interspecific interactions in defining the parapatric contact between closely related species (Crotalus mitchellii and C. stephensi) and to predict refugia during the last glacial maximum. The modelled suitable habitat for C. stephensi correctly predicts the existing parapatric border between it and C. mitchellii, suggesting that C. stephensi's range at the border is limited by climatic factors. In contrast, the suitable habitat for C. mitchellii does not correctly predict the existing parapatric boundary; rather the suitable habitat of this species extends into the range of C. stephensi, suggesting the latter species, not climatic factors, limit the range of C. mitchellii. Modelled refugia of C. stephensi are much smaller than modern suitable habitat and are partially situated at the current parapatric border, whereas the refugia of C. mitchellii are similar to its current suitable habitat, though also shifted to the south. Ecological niche modelling appears to be a useful tool for studying the interplay between climate and competition in determining boundaries between parapatric species. It also appears to be useful for predicting past suitable habitats of species, because predicted refugia are congruent with independent estimates from molecular phylogeography.

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