Distinctiveness, rarity and conservation in a subtropical highland conifer

Abstract

Juniperus blancoi is a rare subtropical conifer with a wide yet restricted distribution and three recognized varieties. In this study, its ecological and genetic exchangeability are tested based on morphological descriptions, habitat differences, size measures, growth form, population genetics estimates and phylogeography, using the trnC-trnD plastid DNA region. Populations show differences in their habitat and morphological characteristics. Phylogeographic structure indicates a complex evolutionary history of expansion, fragmentation, and isolation processes. This resulted in high haplotype diversity (h = 0.863) and differentiation values (D est = 0.866 and D est [ 0.5 in most pairwise comparisons) and a clear geographic structure with well defined groups. As a consequence, although the species has only 8 known populations, it must be divided into at least five distinct conservation units. Thus protecting a rare species could imply the conservation of a complex evolutionary history of non-exchangeable populations.

Morphological and niche divergence of pinyon pines

“…; Mastretta‐Yanes et al. ), and it is under this scenario that diversification by adaptation and niche divergence could be particularly prone to occur, because these isolated populations would also be subjected to differences in local environmental conditions. In this sense, our study supports the idea that the high habitat heterogeneity of the Mexican highlands promoted niche divergence of pinyon pines, thus contributing to the high species richness of conifers for this region.…”

“…During Late Miocene and Pliocene, episodic climatic fluctuations occurred (Metcalfe et al 2000;Zachos et al 2001), leading to scenarios of altitudinal migration where species distribution ranges expanded or contracted as result of climate fluctuations, in many cases leading to species having a fragmented distribution across the Mexican highlands (Mastretta-Yanes et al 2015). This history of expansions and contractions seems to explain the distribution of genetic variation of tropical and subtropical conifer species (Jaramillo-Correa et al 2008;Moreno-Letelier and Piñero 2009;Gugger et al 2011;Mastretta-Yanes et al 2012), and it is under this scenario that diversification by adaptation and niche divergence could be particularly prone to occur, because these isolated populations would also be subjected to differences in local environmental conditions. In this sense, our study supports the idea that the high habitat heterogeneity of the Mexican highlands promoted niche divergence of pinyon pines, thus contributing to the high species richness of conifers for this region.…”

Vegetación de la Sierra Madre Occidental, México: una síntesis

“…En el Cerro Gordo, Huehuento y Mohinora destaca la presencia de un arbusto postrado (Junipe� rus blancoi var. huehuentensis) (Adams et al, 2006;Mastretta-Yanes et al, 2011). En los Cerros Gordo y Mohinora algunos individuos de pino alcanzan la parte alta, pero en general la cima carece de árboles.…”

Late Miocene lineage divergence and ecological differentiation of rare endemic Juniperus blancoi: clues for the diversification of North American conifers

“…huehuentensis ), ecological similarity from the PCA, and the population groups reported in Mastretta‐Yanes et al . () for chloroplast sequences. These analyses were performed using Arlequin 3.5 (Excoffier & Lischer, ).…”

“…The analysis was performed first with the trnC ‐ trnD chloroplast region used in Mastretta‐Yanes et al . () in order to establish the monophyly of the species complex. We included J. blancoi 's sister species Juniperus scopulorum (, , ), Juniperus virginiana (, ) and Juniperus silicicola (; Adams, ; Mao et al ., ) using sequences obtained from GenBank.…”