Poster

         Physiology

Intraspecific variation in hydraulic traits of cycads: environmental correlation and conservation implications

Presenting Author
Nicolas Zepeda
Description
Cycads (Cycadales) are among the world’s oldest and most threatened seed plant lineages. Protecting species in this group from extinction threats such as poaching, habitat destruction, and climate change will require a holistic approach that incorporates many elements of organismal biology. However, several fundamental aspects of cycad biology remain unknown, and data on the ecophysiology of these unique plants is particularly scarce. The extant members of the cycad genus Encephalartos, which inhabit southern Africa, are particularly vulnerable, and urgent conservation interventions are needed to preserve these organisms. Here, we present the first data from wild populations on intraspecific variation in hydraulic anatomy and investigate the role of physiology as a potential factor in determining climate vulnerability of 3 species of Encephalartos. Leaf samples were collected from 12 wild populations and 3 ex situ collections and analyzed for a variety of leaf hydraulic trait anatomical determinants paired with environmental data. We found a high degree of intraspecific trait variation in the three species we examined. We also found that most hydraulic traits can be predicted by native environments, but that trait by environment relationships differed between species. Overall, our results show that threatened Encephalartos spp. are able to adjust key functions across spatial environmental gradients. Thus, conservation efforts should consider these biodiversity patterns when prioritizing species and sites of high conservation value, selecting in situ approaches, and planning ex situ interventions. Ongoing work will shed light on possible hydraulic trait differences between ex situ collections and wild populations and on the implications of those findings for conservation ecology research.