Reconstruction of the spatio-temporal diversification and ecological niche evolution ofHelianthemum(Cistaceae) in the Canary Islands using genotyping-by-sequencing data

Abstract

Background and Aims Several biogeographical models have been proposed to explain the colonization and diversification patterns of Macaronesian lineages. In this study, we calculated the diversification rates and explored what model best explains the current distribution of the 15 species endemic to the Canary Islands belonging to Helianthemum sect. Helianthemum (Cistaceae). Methods We performed robust phylogenetic reconstructions based on genotyping-by-sequencing data and analysed the timing, biogeographical history and ecological niche conservatism of this endemic Canarian clade. Key Results Our phylogenetic analyses provided strong support for the monophyly of this clade, and retrieved five lineages not currently restricted to a single island. The pristine colonization event took place in the Pleistocene (~1.82 Ma) via dispersal to Tenerife by a Mediterranean ancestor. Conclusions The rapid and abundant diversification (0.75–1.85 species per million years) undergone by this Canarian clade seems the result of complex inter-island dispersal events followed by allopatric speciation driven mostly by niche conservatism, i.e. inter-island dispersal towards niches featuring similar environmental conditions. Nevertheless, significant instances of ecological niche shifts have also been observed in some lineages, making an important contribution to the overall diversification history of this clade.

Systematic implications from a robust phylogenetic reconstruction of the genus Helianthemum (Cistaceae) based on genotyping-by-sequencing (GBS) data

“…The assignation of the endemic species from the Horn of Africa to this section is based on and Martín-Hernanz & al. (2021).…”

Are Cenozoic relict species also climatic relicts? Insights from the macroecological evolution of the giant sedges ofCarexsect.Rhynchocystis(Cyperaceae)

“…The dataset including the mean value per variable for extant species was used to construct a PCA. We used the values per species obtained for the first principal component (PC1) as a proxy of its climatic niche because this axis explained a high percentage of the total variance of the climatic data (>70%; see below) in this group, as shown in Albaladejo et al (2020). Finally, we assessed the maximum likelihood (ML) of ancestral state reconstruction under two models of continuous trait evolution (the random drift of Brownian motion [BM] and the constant stabilizing selection of the Ornstein‐Uhlenbeck [OU] process) in the R package phytools (Revell, 2012).…”

Macaronesia as a Fruitful Arena for Ecology, Evolution, and Conservation Biology

“…Such niche differentiation can be reflected in current species distribution, as occurs in some plant clades in the Canary Islands, where closely related taxa present different climatic niches, particularly in allopatry (Steinbauer et al, 2016). However, not all diversification processes have arisen from changes in species niches; niche conservatism, which can be described as the tendency for ancestral niche and ecological characteristics to remain unchanged through time and space (Wiens and Graham, 2005), has also been an important speciation outcome in different taxa (e.g., Helianthemum- Albaladejo et al, 2021). Notably, the flora of the Azores is characterised by a limited incidence of adaptive radiations, contrasting with other Macaronesian archipelagos (Carine and Schaefer, 2010); the debate about the drivers of this pattern has pinpointed past climatic conditions, age, area and environmental homogeneity as the most plausible causes (Carine and Schaefer, 2010;Carine et al, 2012;Triantis et al, 2012).…”