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Aspects of reproductive success are fundamental to a better understanding of the evolution and management of wild species and therefore to design successful conservation strategies. In this study, we evaluated the reproductive success and population size of Aechmea winkleri, a bromeliad found in southern Brazilian Atlantic rainforest in only two regions known to date. The southernmost population of A. winkleri was sampled for this study, where three sites were evaluated during two years (2009 and 2010). We found high production of flowers, fruits, and seeds, as well as high pollen viability. However, a significant decrease in the number of fruits with seeds was detected in 2010 at one of the sites. This result is probably related to a decrease in the number of flowering ramets detected at the same site in 2010. Differences at the seed set were found among the three localities investigated. The site with the highest seed set was the same that presented the highest number of genets. We did not detect pollen limitation at the southernmost population in 2009. We found 390 genets in the three sites combined in 2010. Most of the ramets were vegetative, indicating high investment by the individuals in clonal reproduction at the southernmost population. Conservation efforts should focus on preserving habitat and protecting adult plants from environmental accidents, destruction, and harvesting.

We investigated the genetic diversity and structure of Aechmea winkleri Reitz, an endemic bromeliad found in Southern Brazilian Atlantic rainforest. Seven nuclear microsatellite markers were used to analyze 162 samples from four localities sampled throughout the entire geographic distribution of the species. Results indicate relatively high levels of genetic diversity with an average of allelic richness of 3.57, and observed and expected heterozygosity of 0.559 and 0.608, respectively. The within-inbreeding coefficient was low, ranging from −0.011 to 0.094. All localities significantly deviated from Hardy–Weinberg equilibrium with three of them showing heterozygosites deficiency. Most of the genetic variation (96.64%) was found within localities. No reduction in population size (bottleneck) was detected. Low levels of genetic differentiation among localities were found with pairwise FST comparisons varying from 0.021 to 0.075. Bayesian analyses revealed that A. winkleri is composed by two genetic groups. The number of migrants per generation was high (>1), which maintain localities' cohesion and gene flow. Despite genetic erosion was not detected in the present study, our results revealed that the four localities sampled actually represent one population, the only known so far in nature. Management strategies for A. winkleri conservation should be undertaken as it is an endemic species which occurs in a biome that has gone through major deforestation and fragmentation. This would avoid the increase of inbreeding rates and the loss of genetic diversity.