Ecological consequences of contrasting dispersal syndromes in New World Ephedra: higher rates of niche evolution related to dispersal ability

Abstract

In this study we selected the New World species of Ephedra to understand the ecological consequences of different dispersal syndromes. The twenty‐three species of Ephedra in the New World have a disjunct distribution in North and South American arid and semi‐arid habitats, exhibiting three dispersal syndromes related to dispersal by birds, wind and rodents. Using DNA sequence data we inferred phylogenetic relationships and lineage divergence times, and used these estimates to test different ecological assumptions. Using comparative methods we tested for correlations between dispersal syndromes and a set of ecological variables (niche breadth, niche evolution, distributional ranges and niche position). We found that speciation events in the New World coincided with the expansion of arid habitats in this region. We suggest that the bird dispersal syndrome is related with higher rates of climatic niche evolution for all variables used, including aridity index, mean annual temperature and mean annual precipitation. Distribution ranges were correlated with niche breadth, they were however not significantly different between dispersal syndromes. Species inhabiting the extremely arid regions on niche axes had narrower niche breadths. We conclude that species whose seeds are dispersed by birds have colonized a broader set of habitats and that those with wind and rodent dispersal syndromes might have promoted the colonization of more arid environments.

Historical reconstruction of climatic and elevation preferences and the evolution of cloud forest-adapted tree ferns in Mesoamerica

“…1), are more recent, from the Neogene to the Quaternary. This corresponds with other groups in the gymnosperms such as cycads and Ephedra , in which ancient lineages underwent a re-diversification beginning in the Miocene into the Pleistocene (Nagalingum et al, 2011; Loera, Ickert-Bond & Sosa, 2015). …”

Pleistocene refugia in the Chihuahuan Desert: the phylogeographic and demographic history of the gymnosperm Ephedra compacta

“…Marker selection was based on a molecular survey in which eight gene regions were sequenced and analysed to estimate levels of DNA polymorphism in E. compacta (see Appendix S1 in Supporting Information). DNA extraction, amplification and sequencing followed Loera, Sosa and Ickert‐Bond () and Loera, Ickert‐Bond and Sosa (). Electropherograms were edited and assembled with Sequencher 4.1.4 (Gene Codes Corporation).…”

The Gnetales: Recent insights on their morphology, reproductive biology, chromosome numbers, biogeography, and divergence times

“…25 in tropical Asia (Markgraf, ; Price, ; Won & Renner, ; Hou et al, ). Multi‐locus analyses of nuclear and plastid DNA sequences have shed light on species relationships within Ephedra and Gnetum (Ickert‐Bond & Wojciechowski, ; Won & Renner, , , ; Ickert‐Bond et al, ; Rydin & Korall, ; Rydin et al, ; Loera et al, , ; Hou et al, ); a few deep nodes within Ephedra and Gnetum still remain statistically poorly supported.…”

“…Molecular phylogenies of Ephedra by now have included 54 of the ≈56 species (Ickert‐Bond & Wojciechowski, ; Rydin et al, ; Huang et al, ; Rydin & Korall, ; Rydin et al, ; Loera et al, ). In combination, they show that the six Mediterranean species form a grade at the base of the phylogeny, while the remaining 50 species from a well‐supported clade.…”

“…All 22 New World species form a clade that is nested within a paraphyletic Old World grade. Within the New World clade, the North American E. pedunculata is the earliest diverging species and sister to two clades, one with ten South American species and one with eleven North American ones (Rydin & Korall, ; Rydin et al, ; Loera et al, ). In the latter, the Mexican E. compacta is the earliest diverging species, albeit with low statistical support (Rydin & Korall, ; Loera et al, ).…”