Neogene and Pleistocene history of Agave lechuguilla in the Chihuahuan Desert

Abstract

Aim The history of Agave lechuguilla, a characteristic and dominant plant of the Chihuahuan Desert, was reconstructed in order to determine the importance of the Neogene orogenic uplift and the Quaternary glacial–interglacial climatic changes on the genetic patterns of a native Chihuahuan Desert species. Location Chihuahuan Desert, Mexico and United States. Methods Chloroplast DNA data from A. lechuguilla were analysed to describe levels of genetic diversity and structure and to infer the species’ demographic history, using traditional methods and approximate Bayesian computation (ABC). The time of divergence of the different haplogroups was estimated with a Bayesian approach. In addition, ecological niche modelling was used to identify possible refugia. Results Molecular dating analyses showed that A. lechuguilla originated 4.46 Ma and later differentiated into four haplogroups. The average chloroplast genetic diversity was low (Hd, 0.24), with high levels of genetic differentiation (GST, 0.780). Demographic analysis, niche modelling and ABC indicated a recent expansion from at least five glacial refugia located south of the species’ current distribution. Main conclusion Agave lechuguilla originated in the Neogene, and the glacial–interglacial events of the Pleistocene resulted in the expansion and contraction of its range, playing an important role in its intraspecific diversification. These contraction–expansion events are consistent with biogeographical regions previously identified in the Chihuahuan Desert.

Contrasting colonization patterns of black mangrove (Avicennia germinans (L.) L.) gene pools along the Mexican coasts

“…The populations from the two coasts are separated by hundreds of kilometres and are both roughly linearly distributed, following similar north–south clines (Figure ). Furthermore, their subtropical location increases the likelihood that glacial populations still exist, in contrast to temperate or boreal taxa (Castellanos‐Morales, Gámez, Castillo‐Gámez, & Eguiarte, ; Roberts & Hamann, ; Scheinvar, Gámez, Castellanos‐Morales, Aguirre‐Planter, & Eguiarte, ). Moreover, they have been likely separated since the closure of the CAI (Cerón‐Souza et al., , ; Dodd, Afzal‐Rafii, Kashani, & Budrick, ; Nettel & Dodd, ) which decreases the likelihood that secondary contact will affect the results (but see Takayama et al., ).…”

Assembly and origin of the flora of the Chihuahuan Desert: The case of sclerophyllous Rosaceae

“…Furthermore, instead of considering the Mexican Plateau as a centre of origin of the flora of the Chihuahuan Desert, phylogeographic research has hypothesized that the southern region of the Mexican Plateau acted as refugium for different plant lineages that migrated either from North or South America (Loera, Ickert‐Bond, & Sosa, ; Ruiz‐Sanchez, Rodriguez‐Gomez, & Sosa, ; Scheinvar, Gámez, Castellanos‐Morales, Aguirre‐Planter, & Eguiarte, ; Vásquez‐Cruz & Sosa, ).…”

“…Likewise climate change during the last glaciation in the Chihuahuan Desert has been documented, suggesting that wet conditions in the Pleistocene were attributed to winter rainfall in contrast with the current summer rainfall regime (Metcalfe, Say, Black, & McCulloch, ). The recorded effect of these climate changes in several plant groups suggests that the glacial‐interglacial cycles of the Pleistocene caused suitable habitat contraction and expansion probably affecting distribution range (Loera et al, ; Ruiz‐Sanchez et al, ; Scheinvar et al, ).…”

Genetic Differentiation and Fragmentation in Response to Climate Change of the Narrow EndemicPsittacanthus auriculatus

“…Overall, results of current ENM and palaeomodeling show that the area currently occupied by studied species is substantially larger than it was during the LIG period and the LGM, suggesting that it has been gradually expanding northward since the LIG period. Previous phylogeographic studies that included plant populations of the Valles Centrales and the Tehuaca´n-Cuicatla´n Valley have shown that their ranges contracted during interglacials and then expanded to colonize northern xeric regions during the glacial periods (the Meztitla´n Valley and the Chihuahuan Desert; e.g., Loera, Ickert-Bond, & Sosa, 2017;Ruiz-Sanchez et al, 2012;Scheinvar et al, 2017) or expanded during the warm/humid LIG period and contracted to one or more southerly refugia during cold/dry glacial maxima (Cornejo-Romero et al, 2017).…”

“…A pattern of glacial survival into southern refugia followed by postglacial recolonization of northern regions seems to be ubiquitous for a variety of temperate taxa (e.g., Hewitt, 2000;Stewart, Lister, Barnes, & Dale´n, 2010). The phylogeographic pattern of southern refugia for temperate species during glacial phases, which generally are confined to the southern portion of the species' distribution during warm climatic phases such as the current interglacial, is not followed by desert-adapted species (Angulo, Amarilla, Anton, & Sosa, 2017;Castellanos-Morales, Ga´mez, CastilloGa´mez & Eguiarte, 2016;Ruiz-Sanchez et al, 2012;Scheinvar et al, 2017). Phylogeographic patterns for studied species of the Chihuahuan Desert biota suggest the opposite pattern, a greatest range contraction during the LIG, with a later expansion to northern areas over the LGM.…”