Physiological, morphological and functional traits of encroaching and non-encroaching savanna trees under contrasting CO2 concentrations, water stress, and grass competition, South Africa, 2022
bibliographic citation: Ripley, B., Simpson, K., Raubenheimer, S., Singini, E., Jones, E., Burgess, T., Carkeek, R., Cramer, M., Dixon, R., Field, K., Hawkins, H., Nell, R., Ngqiyaza, N., Pallett, N., Reynolds, L., Telford, E., Vetter, S., Lehmann, C., Osborne, C. (2026). Physiological, morphological and functional traits of encroaching and non-encroaching savanna trees under contrasting CO2 concentrations, water stress, and grass competition, South Africa, 2022. NERC EDS Environmental Information Data Centre. https://doi.org/10.5285/f7b8e72f-9bbe-4a03-8140-fada73e95b8c
description: This dataset provides physiological, morphological, and functional trait measurements for twelve African savanna tree species belonging to the Vachellia and Senegalia genera (Fabaceae family). The data encompasses six species classified as encroaching (increasing in density in African savannas) and six non-encroaching species, facilitating comparative analysis of traits facilitating encroachment ability. The variables capture sapling responses to a factorial combination of environmental conditions, specifically atmospheric carbon dioxide concentration, water availability, and interspecific grass competition. The dataset details plant performance under elevated CO2 versus ambient CO2 and contrasts well-watered and water-limited conditions. Furthermore, the data includes comparative metrics for trees grown with and without competition from the grass species Themeda triandra. All measurements were derived from saplings grown for 11 months in large pots containing local savanna soil within open-top chambers (Rhodes University Elevated CO2 Facility, Makhanda, South Africa), culminating in physiological assessments and destructive harvesting for morphological analysis. The work was supported by the Natural Environment Research Council (Grant NE/T000759/1).
provenance: ProvenanceStatement
  label: Data Generation Process The data were generated through a controlled split-plot experiment conducted at the Rhodes University Elevated CO2 Facility (RUECF) in Makhanda, South Africa. Experimental Setup and Environmental Monitoring Data generation began with the establishment of pots in sixteen open-top chambers (OTCs) designed to impose specific environmental treatments. These treatments included manipulated atmospheric CO2 concentrations (ambient vs. elevated to ~550 ppm), water availability (automated daily irrigation vs. ambient rainfall), and interspecific competition (pots containing established Themeda triandra grass swards vs. bare soil). Cultivation of Biological Material The biological data component originated from twelve indigenous legume species (Vachellia and Senegalia spp.) selected based on their encroachment status. Seeds were heat-shocked to break dormancy, germinated and transplanted into the experimental OTCs. These saplings were grown under the assigned factorial treatment conditions for a period of 11 months (December 2021 - November 2022). Data Acquisition Final data collection was performed in two stages. In the month preceding harvest, physiological trait data were captured in situ. Subsequently, the experiment concluded with the destructive harvesting of all individuals. Morphological and functional trait data were then generated through the physical measurement and analysis of the harvested biomass.
spatial: Location
temporal: PeriodOfTime
  start date: 2021-12-01
  end date: 2022-11-30
publisher: NERC EDS Environmental Information Data Centre
subject: Climate and climate change
subject: Savanna encroachment
subject: Woody thickening
subject: Elevated CO2
subject: Functional traits
subject: Drought
subject: Tree-grass competition
type: Dataset
available: 2026-02-04
landing page: https://doi.org/10.5285/f7b8e72f-9bbe-4a03-8140-fada73e95b8c
license: plain
access rights: EMBG
theme: Climate and climate change
creator: Ripley, B.
creator: Simpson, K.
creator: Raubenheimer, S.
creator: Singini, E.
creator: Cramer, M.
creator: Field, K.
creator: Hawkins, H.
creator: Nell, R.
creator: Telford, E.
creator: Vetter, S.
creator: Lehmann, C.
creator: Osborne, C.
language: en

Kimberley Simpson
type: Person
member: University of Sheffield

NERC EDS Environmental Information Data Centre
type: Organization

Ripley, B.
type: Person
family name: Ripley
given name: Brad
member: Rhodes University

Simpson, K.
type: Person
family name: Simpson
given name: Kimberley
member: University of Sheffield

Raubenheimer, S.
type: Person
family name: Raubenheimer
given name: Sarah
member: University of Michigan

Singini, E.
type: Person
family name: Singini
given name: Edith
member: Rhodes University

Jones, E.
type: Person
family name: Jones
given name: Emma
member: Rhodes University

Burgess, T.
type: Person
family name: Burgess
given name: Tebadi
member: Rhodes University

Carkeek, R.
type: Person
family name: Carkeek
given name: Richard
member: Rhodes University

Cramer, M.
type: Person
family name: Cramer
given name: Michael
member: University of Cape Town

Dixon, R.
type: Person
family name: Dixon
given name: Russell
member: Rhodes University

Field, K.
type: Person
family name: Field
given name: Katie
member: University of Sheffield

Hawkins, H.
type: Person
family name: Hawkins
given name: Heidi
member: University of Cape Town

Nell, R.
type: Person
family name: Nell
given name: Rhys
member: Rhodes University

Ngqiyaza, N.
type: Person
family name: Ngqiyaza
given name: Nozuko
member: Rhodes University

Pallett, N.
type: Person
family name: Pallett
given name: Nita
member: Rhodes University

Reynolds, L.
type: Person
family name: Reynolds
given name: Liam
member: Rhodes University

Telford, E.
type: Person
family name: Telford
given name: Elizabeth
member: University of Sheffield

Vetter, S.
type: Person
family name: Vetter
given name: Susanne
member: Rhodes University

Lehmann, C.
type: Person
family name: Lehmann
given name: Caroline
member: Royal Botanic Garden Edinburgh

Osborne, C.
type: Person
family name: Osborne
given name: Colin
member: University of Sheffield

Climate and climate change
type: Concept

Rhodes University
type: Organization

University of Sheffield
type: Organization

University of Michigan
type: Organization

University of Cape Town
type: Organization

Royal Botanic Garden Edinburgh
type: Organization