Investigating pollination strategies in disturbed habitats: the case of the narrow-endemic toadflax Linaria tonzigii (Plantaginaceae) on mountain screes.

Raw data concernig the pollination biology and genetic identity of Linaria tonzigii. It includes: Seed number, seed weight and seed viability per breeding treatment; Genetic identity of several DNA regions of Linaria tonzigii, vulgaris and alpina. <br><b>Abstract</b> Plant mating system may reflect an adaptation to a habitat type, with self-pollination being potentially common in unstable and disturbed conditions. We investigated the reproductive ecology of an Alpine, narrow-range toadflax, <i>Linaria tonzigii </i>(Plantaginaceae), occurring in steep and dynamic mountain screes. We explored self-compatibility and spontaneous autogamy, seed viability, daily nectar production, pollinator behaviour and pollen transfer in wild populations, using hand-pollination treatments, quantification of nectar volume, viability Tetrazolium assay, active pollinator sampling and video recordings, and UV-bright dust for pollen substitution. After <i>ex novo</i> sequencing of several genetic regions of <i>L. tonzigii</i>, we performed a multi-marker phylogenetic analysis of 140 <i>Linaria</i> species and tracked the occurrence of the self-compatibility trait. Our results showed that this species is self-compatible, pollinated mostly via spontaneous autogamy and pollinator-mediated geitonogamy, and self-pollinated seeds are as viable as cross-pollinated ones. Selfing could be due to pollinator rarity because, despite the studied species providing a high nectar volume, wild bees, moths and small beetles infrequently visited its flowers in the sparsely vegetated scree slopes. In addition, a preliminary survey showed that genetic diversity is low in the study plant. Moreover, the phylogeny shows that self-compatibility is scattered in the tree, suggesting the adaptive nature of this reproductive system in the genus <i>Linaria</i>. This study contributes to supporting theories that high prevalence of selfing is an adaptation to environments unfavourable to cross-pollination, and particularly where pollinators are rare such as in perturbed, poorly vegetated high-elevation habitats. <br><b>Please cite: Biella et al. - Investigating pollination strategies in disturbed habitats: the case of the narrow-endemic toadflax <i>Linaria tonzigii </i>(Plantaginaceae) on mountain screes. Plant Ecology (2021)</b><br>