Abstract Detail

Biogeography

Young, Sophie [1], Dunning, Luke [2], Stevens, Carly [3], Lundgren, Marjorie [4].

The Biogeography of Photosynthetically Diverse Trees in Euphorbiaceae.

The Euphorbiaceae family, and the genus Euphorbia in particular, is remarkably morphologically and photosynthetically diverse. It spans growth forms from herbs to xerophytic stem succulents to trees of up to 30m in height, and includes diverse species utilising C₃, C₂, C_4, and CAM types of photosynthesis. The C₄ lineage in Euphorbia is the largest C₄ lineage found among the eudicots, and contains the only true C₄ trees. These C₄ trees are endemic to the Hawaiian Islands, where they diversified from an herbaceous ancestor following a single colonisation event. In addition to these unique C₄ trees, Euphorbia also contains CAM and C₃ trees, some of which occur alongside C₄ tree species on the Hawaiian Islands. Previous studies of Euphorbia trees found that they grow across a broad range of latitudes and biomes globally, occupying a range of environments from arid shrublands to wet forest understories. This study will present the geographical and ecological distributions of these photosynthetically diverse trees on the Hawaiian Islands, using Global Biodiversity Information Facility (GBIF) and Botanical Information and Ecology Network (BIEN) occurrence data and local environmental and soil raster datasets. Key biogeographic factors that determine the distribution of these photosynthetically diverse tree species will be discussed within a phylogenetic framework to reveal factors that may have shaped the photosynthetic fate of each lineage. For the first time, our study distinguishes the ecological factors that support photosynthetic diversification in the tree life form. These findings will help to inform ongoing research¹ into why C₄ trees are so rare, and how the geography and ecology of the Hawaiian Islands have influenced the diversification of C₄ trees in Euphorbia.
1. Young S.N.R. et al. Why is C₄ photosynthesis so rare in trees? J. Exp. Bot (2020)

1 - Lancaster University, Lancaster Environment Centre, Library Avenue, Lancaster, LAN, LA1 4YQ, United Kingdom
2 - University of Sheffield, Department of Animal and Plant Sciences, Alfred Denny Building, , Western Bank,, Sheffield , S10 2TN, UK
3 - Lancaster University, Lancaster Environment Centre, Library Avenue, Lancaster, LAN, LA1 4YQ, UK
4 - Lancaster University, Lancaster Environment Centre, Farrer Avenue, Bailrigg, LAN, LA1 4YQ, United Kingdom

Keywords:
biogeography
C₄ photosynthesis
Chamaesyce
Euphorbiaceae
Euphorbia
Hawaiian Islands.

Presentation Type: Oral Paper
Session: BIOGI, Biogeography I
Location: Virtual/Virtual
Date: Monday, July 19th, 2021
Time: 1:00 PM(EDT)
Number: BIOGI003
Abstract ID:343
Candidate for Awards:None