This data set provides the photosynthetic pathways for 2428 species recorded across 541 plots surveyed by Australia’s Terrestrial Ecosystem Research Network (TERN) between 2011 and 2017 (inclusive). TERN survey plots are 1 ha (100 x 100 m) permanently established sites located in a homogeneous area of terrestrial vegetation. At each plot, TERN survey teams record vegetation composition and structural characteristics and collect a range of plant samples using a point-intercept method. Species were assigned a photosynthetic pathway using literature and carbon stable isotope analysis of bulk tissue collected by TERN at the survey plots.
The data set is comprised of two data tables and one data descriptor that defines the values in the two data tables. The first table contains a list of each species and its photosynthetic pathway. The second table includes a list of all the peer-reviewed sources used to create this data set.
This data set will be updated on an annual basis as TERN’s plot network expands and new information becomes available.
We at TERN acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging.
We would like to acknowledge the TERN Ecosystem Surveillance field team for their work collecting the voucher specimens used in the δ13C analysis. We would also like to acknowledge the support of TERN by the Australian government through the National Collaborative Research Infrastructure Strategy. Additional financial support for this project was provided by the AMP Foundation and the AMP Tomorrow Fund awarded to S.M., the Australian Research Council Future Fellowship (FT110100100793) awarded to F.A.M., and Australian Government Research Training Program and University of Adelaide Faculty of Sciences Divisional scholarships awarded to J.W.A.
This photosynthetic pathway data set was created by TERN to enable research examining the abundance, richness, and distribution of C4 and C3 vegetation in Australia.
A full list of the studies consulted is provided within the data file.
Photosynthetic pathway assignment : All TERN plant data were processed in the R statistical environment using the ‘ausplotsR’ package. A list of all vascular plant species at each TERN plot was extracted using the get_ausplots function. To assign each species a photosynthetic pathway, scientific names were first cross-referenced against well-known plant trait databases. We then conducted literature searches of the remaining unassigned species via Google Scholar with combinations of the key words “C3”, “C4”, “CAM”, “photosynthesis” and “photosynthetic pathway”. If species-specific information was not available, but the species belonged to a genus known to be exclusively C3, C4 or CAM it was assigned to that pathway (e.g. Acacia spp., Eucalyptus spp. are presumptive C3). If it was not possible to assign a photosynthetic pathway using published sources or presumptive reasoning, then that species was selected for stable carbon isotope analysis.
Stable Isotope Analysis: The carbon stable isotope values of C3 plants range from -37‰ to -20‰ δ13C (mean= ~-27‰), the values of C4 plants range from -12‰ to -16‰ δ13C (mean=~-13‰). For species where either a C3 or C4 pathway was possible, plants with δ13C values < -19‰ were designated C3, and plants with δ13C values > -19‰ were designated C4. Full CAM plants, or plants in which CAM is strongly expressed, have δ13C > -20‰. However, CAM photosynthesis almost always co-exists with the C3 pathway (C3-CAM). The δ13C of C3-CAM plants are correlated with the proportion of carbon that is obtained during light and dark periods. As a result, C3-CAM δ13C values are highly variable (approximately -13‰ to -27‰). To confirm the presence of CAM, additional measures of other physiological and biochemical variables are usually required. With this limitation in mind, for genera with previously confirmed C3-CAM potential, we tentatively denoted plants with a δ13C value > −20‰ as CAM, −21‰ to −24‰ as C3-CAM, and <−24‰ as C3.