The effects of climate change on the geographic distribution of Mexican wild relatives of domesticated Cucurbitaceae

Using bioclimatic modeling, two possible scenarios of climatic change in Mexico were used to analyze the distribution patterns of eight wild Cucurbitaceae closely related to cultivated plants [Cucurbita argyrosperma Huber ssp. sororia (L. H. Bailey) Merrick et Bates, C. lundelliana L. H. Bailey, C. pepo L. ssp. fraterna (L. H. Bailey) Andres, C. okeechobeensis (J. K. Small) L. H. Bailey ssp. martinezii (L. H. Bailey) Walters et Decker-Walters, Sechium chinantlense Lira and Chiang, S. compositum (J. D. Smith) C. Jeffrey, S. edule (Jacq.) Sw. ssp. sylvestre Lira et Castrejón, and S. hintonii (P. G. Wilson) C. Jeffrey]. Most of these taxa have restricted distributions. Many of them also show proven resistance to various diseases, which could be crucial for the improvement of their related cultivars. The possible role that the Mexican system of protected areas might have in the conservation of these taxa was also assessed. The results showed a marked contraction of the distributions of all eight taxa under both scenarios. We also found that, under a drastic climatic change scenario, the eight taxa will be maintained in just 29 out of the 69 natural protected areas where they currently occur. Accordingly, it seems that most of the eight wild taxa will not have many opportunities to survive under climate change. However, the ability of these plants to maintain low-density isolated populations for long periods, as well as the low resolution of the bioclimatic models, are discussed as possible mitigators of these rather grim predictions.