Impact of Late Pleistocene-Holocene climatic fluctuations on the phylogeographic structure and historical demographics of Zamia prasina (Cycadales: Zamiaceae)

Abstract

Background: Glacial periods during the Pleistocene have been hypothesized to have greatly influenced geographical patterns of genetic structure and demography of many tropical species. The Glacial Refugium Hypothesis proposes that, during cold, dry glacial periods, populations of moisture-affinities tropical species were restricted to sheltered, humid areas and that, during warmer and more humid interglacial periods, these populations expanded. Some mountain regions in the tropics acted as refugia during the cold, dry periods of the Pleistocene for several temperate forest taxa, which recolonized the humid areas farther north during the interglacial periods.Questions: (1) Did Late Pleistocene-Holocene climate changes affect the historical demophraphy of Zamia prasina? (2) Does the historical distribution of Zamia prasina agree with the Glacial Refugium Hypothesis?Study species: Zamia prasina W.Bull. (Zamiaceae), the only cycad native to the Yucatan Peninsula Biotic Province (YPBP). Methods: Five individuals were collected in 23 populations and characterized using two DNA regions: plastid atpF-atpH, and nuclear ITS2. Genetic diversity, phylogeographic structure, historical demography, and potential distributions were assessed. Results: Our results showed moderately high genetic diversity and low, but significant, phylogeographic structure. Two genetic groups were identified, one in the eastern part of the Peninsula, the other in the western. The changes in historical demography suggest that Z. prasina experienced a population expansion following the warm conditions of the Holocene.Conclusions: The population dynamics of Zamia prasina are in accordance with the Glacial Refugium Hypothesis.

The role of ecological niche conservatism in the evolution of bird distributional patterns in Mesoamerican seasonally dry forests

“…Increased environmental suitability was predicted from early to mid‐Holocene, following the gradual establishment of similar‐to‐present environmental conditions (Brenner et al., 2002; Carrillo‐Bastos et al., 2010; Metcalfe et al., 2000). Our results are concordant with phylogeographical studies of local plants (Montalvo‐Fernández et al., 2019) and mammals (León‐Tapia, 2021).…”

“…Our models for species currently endemic to the MPS-SDF match et al, 2021), in which a southbound shift for the YP populations have also been found in other taxa (Castillo-Chora, Zamudio-Beltrán, et al, 2021;Montalvo-Fernández et al, 2019). For M. mexicanus, we found widespread climatically stable areas along the MPS (see also Arbeláez-Cortés et al, 2014), while suitable conditions for the YP population and with MPS-VS, were restricted to the northern and most arid part of the YP (Paynter, 1955), which have not been documented in previous studies.…”

“…The inverse pattern was found for G. velox, A. rutila and F. cyanopygius, which roughly resembles the Glacial Refugia Hypothesis, in which species ranges contracted to refugia during the cold/dry glacial periods and later expanded following warm/humid interglacial periods (Avise & Walker, 1998;Cornejo-Romero et al, 2017;Hewitt, 2000). These patterns have been also described in Neotropical dryland plants (Contreras-Negrete et al, 2021;Cornejo-Romero et al, 2017;Montalvo-Fernández et al, 2019;Ornelas et al, 2018).…”

“…Considering that fossils correspond to the Pleistocene–Holocene boundary, their presence predates this time, as suggested by our LIG and LGM projections. For F. cyanopygius , range contraction in the MPS matched climatic stability areas in the region (Arbeláez‐Cortés et al., 2014; Arbeláez‐Cortés & Navarro‐Sigüenza, 2013; Castillo‐Chora, Sánchez‐González, et al., 2021), in which a southbound shift for the YP populations have also been found in other taxa (Castillo‐Chora, Zamudio‐Beltrán, et al., 2021; Montalvo‐Fernández et al., 2019). For M. mexicanus , we found widespread climatically stable areas along the MPS (see also Arbeláez‐Cortés et al., 2014), while suitable conditions for the YP population and with MPS‐VS, were restricted to the northern and most arid part of the YP (Paynter, 1955), which have not been documented in previous studies.…”

Biogeographical History of the Yucatan Peninsula Endemic Flora (Spermatophyta) from a Phylogenetic Perspective1

“…This climatic change possibly caused the extinction of entire communities of boreal species, leaving only a few relict communities of endemic species or ‘paleoendemic’ species, respectively. A phylogeographic study of Zamia prasina W. Bull (Zamiaceae) shows that its populations remained restricted to the southeastern YPBP during the Last Glacial Maximum (Pleistocene-Holocene) (Montalvo-Fernández et al, 2019). Paleoclimatic reconstruction models employed in that work indicate very few or no environments available for successful establishment of populations in the YPBP at that time, which suggests scenarios of local extinction followed by the re-expansion of the distribution range throughout the warmer Mid-Holocene periods.…”