Abstract
The mechanisms underlying plant species distribution and abundance have
been long studied in ecology. However, the role of heterospecific pollen
interference in shaping these patterns needs more attention. Species
distribution and abundance are important factors determining whether a
species is endangered or not, thus understanding the impact of
heterospecific pollen interference on rare species could help to inform
conservation strategies aimed at preserving plant communities.
In this study, we conducted a multispecies experiment using eight
co-occurring and co-flowering plant species with varying rarity levels
in Switzerland. We performed hand-pollination experiments between all
species pairs and measured seed set (whether a flower produces seed) and
seed number (number of seeds per flower) as outcomes. We looked at the
effects of rarity status, self-compatibility and recipient-donor
relatedness on heterospecific pollen interference.
Contrary to expectations, neither seed set nor seed number were affected
by heterospecific pollen deposition. Self-compatible species had a
higher seed set probability, but this was independent from species
rarity. In our study setting, heterospecific pollen interference seems
to have only minor effects on seed set and seed number, and consequently
on recruitment. Thus, heterospecific pollen interference seems to play
only a minor role in shaping plant species distribution and abundance.
Nevertheless, the higher impact of heterospecific pollen deposition on
rare and closely related species, as well as the importance of
conspecific pollen loss, might need further investigation for both
in-situ and ex-situ conservation strategies.Keywords: common species; self-incompatible species;
phylogenetic distance; pollen recipient; Caucalidion