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.