Past Climate Change and Plant Evolution in Western North America: A Case Study in Rosaceae

Abstract

Species in the ivesioid clade of Potentilla (Rosaceae) are endemic to western North America, an area that underwent widespread aridification during the global temperature decrease following the Mid-Miocene Climatic Optimum. Several morphological features interpreted as adaptations to drought are found in the clade, and many species occupy extremely dry habitats. Recent phylogenetic analyses have shown that the sister group of this clade is Potentilla section Rivales, a group with distinct moist habitat preferences. This has led to the hypothesis that the ivesioids (genera Ivesia, Horkelia and Horkeliella) diversified in response to the late Tertiary aridification of western North America. We used phyloclimatic modeling and a fossil-calibrated dated phylogeny of the family Rosaceae to investigate the evolution of the ivesioid clade. We have combined occurrence- and climate data from extant species, and used ancestral state reconstruction to model past climate preferences. These models have been projected into paleo-climatic scenarios in order to identify areas where the ivesioids may have occurred. Our analysis suggests a split between the ivesioids and Potentilla sect. Rivales around Late Oligocene/Early Miocene (∼23 million years ago, Ma), and that the ivesioids then diversified at a time when summer drought started to appear in the region. The clade is inferred to have originated on the western slopes of the Rocky Mountains from where a westward range expansion to the Sierra Nevada and the coast of California took place between ∼12-2 Ma. Our results support the idea that climatic changes in southwestern North America have played an important role in the evolution of the local flora, by means of in situ adaptation followed by diversification.

Diversification of the phaseoloid legumes: effects of climate change, range expansion and habit shift

“…Moreover, Asia and America also experienced an analogous arid period (Guo et al, 2002; Minnich, 2007; Graham, 2010). The extensive aridity can have promoted the diversification of some groups inhabiting in dry regions, such as Bursera (De-Nova et al, 2012) and the ivesioids of Potentilla (Töpel et al, 2012). De-Nova et al (2012) postulated that Bursera diversification during the Miocene might be related to the expansion of Mesoamerican seasonally dry tropical forests.…”

Origins of Plant Diversity in the California Floristic Province

“…Other xeric-adapted woody taxa primarily associated with the CA-FP that molecular data indicate as having diverged from their nearest relatives in the Paleogene include Adenostoma (Rosaceae; Töpel et al 2012), Cneoridium (sister to Old World Haplophyllum, Rutaceae; Salvo et al 2010), Malosma (Anacardiaceae; Yi et al 2004), and Aesculus californica (Sapindaceae; Harris et al 2009). Molecular evidence for mesic-adapted, woody CA-FP endemic angiosperms of similar antiquity is relatively limited, e.g., Cornus sessilis (Cornaceae; Xiang et al 2008).…”

“…Growing appreciation for the importance of ecology in understanding evolutionary change and recent evidence indicating evolutionary decoupling of niche parameters warrants more attention to resolving the history of ecological factors in a phylogenetic context as well (e.g., Emery et al 2012, Töpel et al 2012, Arrigo et al 2013, Anacker & Strauss 2014, in part to characterize likely future responses of lineages to environmental change. Field-based descriptive and experimental work is invaluable to these goals and, although often difficult and unavoidably slow, continues to be the source of some of the most important contributions to evolutionary understanding of the California flora (e.g., Ramsey et al 2003, Angert & Schemske 2005, Lowry et al 2008.…”

Climatic niche shift of aquatic plant invaders between native and invasive ranges: a test using 10 species across different biomes on a global scale

“…Furthermore, Zhu et al (2013) used MAXENT modeling to project potential distributions of Spartina alterniflora on a global scale, based on the transferability of ENM predictions between native and invasive ranges. Climatic niche conservatism is the key assumption for the evaluation of the impact of climate change on distributions of invasive plant species (Petitpierre et al, 2012;Wiens and Graham, 2005;Töpel et al, 2012;Corlett and Westcott, 2013). Previous studies reported climatic factors to be an important driving force behind plant invasion into nonnative regions, because invasive plant species typically spread into areas with climatic conditions, similar to their native habitat; this is referred to as climatic niche conservatism (Petitpierre et al, 2012;Corlett and Westcott, 2013;Donoghue and Edwards, 2014).…”