Correlates of Diversification in the Plant Clade Dipsacales: Geographic Movement and Evolutionary Innovations

Abstract

We explore patterns of diversification in the plant clades Adoxaceae and Valerianaceae (within Dipsacales), evaluating correlations between biogeographic change (i.e., movements into new areas), morphological change (e.g., the origin of putative key innovations associated with vegetative and reproductive characters), and shifts in rates of diversification. Our findings indicate that rates of diversification in these plants tend to be less tightly correlated with the evolution of morphological innovations but instead exhibit a pronounced correlation with movement into new geographic areas, particularly the dispersal of lineages into new mountainous regions. The interdependence among apparent novelties (arising from their nested phylogenetic distribution) and the correlation between morphological and biogeographic change suggests a complex history of diversification in Dipsacales. Overall, these findings highlight the importance of incorporating biogeographic history in studies of diversification rates and in the study of geographic gradients in species richness. Furthermore, these results argue against a simple deterministic relationship between dispersal and diversification: like other factors that may influence the probability of speciation and/or extinction, the impact of dispersal on diversification rates depends on being in the right place at the right time.

Climate‐driven diversity dynamics in plants and plant‐feeding insects

“…Although many speciation modes operate in plants, a considerable proportion of lineage splits probably occur allopatrically, i.e., as a result of geographic isolation of initially conspecific populations that over time diverge enough to become separate species (Moore & Donoghue 2007;Valente et al 2010). Changes in climate can rapidly shift and fragment the geographic distributions of plant species (Rodríguez-Sánchez & Arroyo 2008;Alsos et al 2009).…”

“…Diffuse cospeciation events are by definition allopatric, but the speciation mode is not so clear in situations in which diversification is driven by a change in the amount of resources. In these cases, the question is whether an apparently climate-associated radiation of a given plant lineage was caused by ecological speciation following minor niche shifts, or whether the speciation burst simply resulted from increased opportunities for allopatric speciation following geographic range expansion (Moore & Donoghue 2007;Linder 2008;Kisel et al 2011)? The corresponding question arises whenever an increase in the spread and diversity of a plant clade appears to have triggered a delayed radiation in insect associates, because the underlying speciation process can be ecological, i.e., driven by host shifts across the species of the plant lineage (Wheat et al 2007;Condamine et al 2012) or non-ecological, following increased possibilities for geographical isolation Imada et al 2011; see also Janz 2011).…”

Biogeography of species richness gradients: linking adaptive traits, demography and diversification

“…Ericson, Irestedt & Johansson, 2003;Hawkins et al, 2007;. Episodes of biogeographic movement and/or isolation are in some cases associated with clear shifts in the diversification rates of clades (Moore & Donoghue, 2007). For example, empirical evidence supports that colonization of mountain chains Table 4.…”

“…Second, big-brained individuals might more easily spread to new locations increasing opportunities for allopatric speciation and reducing extinction risk (Sol et al, 2002(Sol et al, , 2005aSol & Price, 2008). favoured isolation and strongly increased diversification rates in birds, butterflies, plants and other taxa (Weir, 2006;Fjeldsa & Rahbek, 2006;Hughes & Eastwood, 2006;Johansson et al, 2007;Moore & Donoghue, 2007;Price, 2008). Jablonski, Roy & Valentine (2006) proposed a general verbal model of global diversification (the ''Out of the Tropics'' model) in which the bulk of the clades preferentially originate in the tropics and only some of them expand towards the poles leading to secondary diversification processes there.…”

Historical biogeography and life-history evolution of AndeanPuya(Bromeliaceae)

“…However, detailed studies involving these cladogenic processes in the Andes and the Neotropics are more common in vertebrates than in plants to date (Young et al, 2002;Hall, 2005;Weir, 2006;Brumfield & Edwards, 2007;Ribas et al, 2007;Torres-Carvajal, 2007;Elias et al, 2009;Santos et al, 2009;Chaves et al, 2011), in part because of greater baseline field knowledge and collecting efforts in some animal groups compared with plant groups. Historical biogeographical explanations for Andean radiations are increasingly based on timecalibrated phylogenies and use of explicit biogeographical models (Richardson et al, 2001;Berry et al, 2004;Kay et al, 2005;Moore & Donoghue, 2007;Alzate, Mort & Ramirez, 2008;Drummond, 2008;Antonelli et al, 2009;Cosacov et al, 2009;Givnish et al, 2011;Luebert, Hilger & Weigend, 2011;Särkinen et al, 2011;Drummond et al, 2012).…”