Dispersal modes affect Rhamnaceae diversification rates in a differentiated manner

Abstract

The evolution of dispersal modes has been proposed to promote the diversification of angiosperms. However, little is known about the relative impact of different dispersal modes on plant diversification. We test the association between dispersal modes and diversification rates using Rhamnaceae, the cosmopolitan buckthorn family, as a model. We found that species with diplochory have the highest diversification rates followed by those with myrmecochory and ballistic dispersal, while lineages dispersed by vertebrates and wind have relatively low diversification rates. The difference in diversification rates may be closely linked to the difference in dispersal distance and ecological interactions implied by each dispersal mode. Species which disperse over larger geographical distances may have much higher speciation rates due to the increased chance of establishing isolated populations due to geological barriers or habitat fragmentation. However, long-distance dispersal may also increase the chance of extinction. By contrast, species with short-distance dispersal modes may have low speciation rates. Complex interactions with the surrounding environment may, however, impact diversification rates positively by increasing plant survival and reproductive success.

Variation in Seed Morphological Traits Affects the Dispersal Strategies of Chromolaena odorata Following Invasion

“…Seeds serve as crucial reproductive units in higher plants, and the traits associated with their germination and dispersal processes significantly influence plant performance, spread, population establishment, and dynamics, ultimately shaping their evolutionary trajectory [2][3][4][5]. Understanding seed variation distributed across different organization levels (i.e., individual, population, and space) and interactions with each other is helpful for understanding the evolution of seeds traits; however, previous studies have predominantly focused on interspecific comparisons [6]. Invasive species with a wide distribution provide an excellent model for investigating intraspecific variations in seed traits under diverse environmental conditions.…”

“…Among the various seed types, wind-dispersed seeds have been extensively investigated [7,8]. The interrelationships among traits such as seed mass, pappus area, and dispersal ability have been thoroughly assessed in numerous species [6,7]. Seed mass is associated with a diverse range of functions [9].…”

“…Invasive plants are introduced into novel and unusual environments, where their seeds experience distinct and intense selection pressures compared with their native range [17][18][19][20]. Different biotic environments (e.g., release from specialist enemies present in the native range) [17,21] drive modifications in functional traits (e.g., seed traits), resulting in changes in seed germination and dispersal potential [6,22,23]. For example, Liu et al (2020) reported that Spartina alterniflora Loisel.…”