Can dispersal investment explain why tall plant species achieve longer dispersal distances than short plant species?

Abstract

SummaryTall plant species disperse further distances than do short species, within and across dispersal syndromes, yet the driver underpinning this relationship is unclear. The ability of taller plants to invest more in dispersal structures may explain the positive relationship between plant height and dispersal distance. Here, we quantify the cross-species relationships between presence of dispersal structures, dispersal investment plant height and dispersal distance.Plant height, dispersal syndrome and dispersal investment data were collated for 1613 species from the literature, with dispersal distance data collated for 114 species.We find that species with high dispersal investment disperse further than do species with low dispersal investment. Tall species have a greater probability of having dispersal structures on their seeds compared with short species. For species with dispersal structures on their seeds, plant height is very weakly related to dispersal investment.Our results provide the first global confirmation of the dispersal investment-distance hypothesis, and show dispersal investment can be used for predicting species dispersal distances. However, our results and those of previous studies indicate plant height is still the best proxy for estimating species dispersal distances due to it being such a readily available plant trait.

High dispersal ability is related to fast life‐history strategies

“…Specifically, we found that high dispersal ability was related to fast life‐history strategies. Previous studies in plants have provided evidence for dispersal syndromes based on phenotypic traits, such as plant height, seed mass and dispersal structures (Tamme et al., ; Thomson et al., , ). Across animal species, Stevens et al.…”

“…Growth form and plant size can constrain the variation of plant life histories, and, in combination with dispersal modes, could constrain dispersal syndromes. Growth form describes potential constraints due to anatomy (Salguero‐Gómez et al., ), while dispersal mode, growth form and plant height explain dispersal distances (Tamme et al., ; Thomson, Letten, Tamme, Edwards, & Moles, ). Salguero‐Gómez et al.…”

European ornamental garden flora as an invasion debt under climate change

“…Results of previous studies are mixed, but when height had a significant effect, it usually was a positive one (Bucharová & van Kleunen, ; Hanspach et al., ; Maurel et al., ). This suggests that at least for some groups of plants, height improves competitive ability and seed‐dispersal (Thompson, Letten, Tamme, Edwards, & Moles, ). Dioecious species were slightly more likely to naturalise than non‐dioecious species (Figure b).…”

Drivers of large‐scale geographical variation in sexual systems of woody plants

“…Studies indicate that tall individuals of dioecious species can even bypass the flow structures induced by plant morphology (e.g., leaves and branches) to ensure further pollen dispersal and increased mating opportunities(Burd & Allen, 1988;Pickup & Barrett, 2012;Thomson, Letten, Tamme, Edwards, & Moles, 2018).Given the well-documented association between plant height and longevity(Marbà et al, 2007;Moles & Leishman, 2008;F I G U R E 2 Comparison between the proportions of species with different sexual systems across different plant heights. Studies indicate that tall individuals of dioecious species can even bypass the flow structures induced by plant morphology (e.g., leaves and branches) to ensure further pollen dispersal and increased mating opportunities(Burd & Allen, 1988;Pickup & Barrett, 2012;Thomson, Letten, Tamme, Edwards, & Moles, 2018).Given the well-documented association between plant height and longevity(Marbà et al, 2007;Moles & Leishman, 2008;F I G U R E 2 Comparison between the proportions of species with different sexual systems across different plant heights.…”