Reproductive biology of the critically endangered endemic mediterranean plant Coincya rupestris subsp. Rupestris (Spain): The effects of competition and summer drought on seedling establishment

Abstract

Flower, fruit, seed production, and flowering phenology (duration, intensity, moment and synchrony) were in the two main populations (south east Spain) of the critically endangered endemic Mediterranean plant Coincya rupestris subsp. rupestris (Cruciferae). Production of flowers and fruits (mean ± SD) ranged from 483 (± 688) to 748 (± 636), and from 317 (± 518) to 553 (± 500), respectively, between populations. In addition, average seed production per plant was 1,607-2,798, thus concluding that fertility was not responsible for rarity of this taxon. The fruit/flower ratio ranged from 0.60 to 0.75, showing significant inter-population . Flowering extended from February-March to the end of spring, with high synchrony (= 85 %). This was negatively correlated with duration of the flowering period. The role of pollinator insects on success, and the effect of watering treatments and the elimination of competitors on seedling were analysed in the classical locality. The exclusion of pollinators dramatically affected , reducing reproductive success from moderate values in plants exposed to insects (= 0.5) to null in those where insects were experimentally excluded. Seedling emergence was autumnal and no of the factors analysed (i.e., water availability and inter-specific competition) was detected on seedling . A high interannual variability in the size and survival of cohorts originated each autumn was . It should be emphasized that the rarity of the taxon is not due to fecundity restrictions.