TGB Osborn (Koonamore) Vegetation Reserve, Senna Populations 

In 1997, many very young Senna seedlings were noticed in the Cassia corner and outside the northern boundary fence. To study the effects of grazing on these seedlings outside the reserve, three populations were identified and measured to the north of the fence, and a fourth population just south of the fence in the Reserve, not otherwise enclosed. Two of the outside populations were enclosed in triangular fences, one with sheep netting to protect from grazing by sheep, the other with both sheep and rabbit netting to protect against both sheep and rabbits. A third population was left unprotected. The population inside the Reserve was assumed to be protected from all grazing by the Reserve fence. The aim was to follow the fates of the original cohort. This is version 2.1 of the TGB Osborn Senna Population data release and supersedes any previous versions. Change log for the Senna population observations:

• V2.1, 2026-02-16; Specht, Miranda Fittock and Arun Singh Ramesh; Ensured dates recorded were in ISO format YYYY-MM-DD. The dataset was edited for accuracy, additions made to data set to comply with TERN standards.
• V2, 2025-04-29; Alison Specht; Digitised and organised data files to comply with FAIR standards, aligning vocabularies with the TERN vocabularies and created comprehensive metadata.
• V1, 2008-2014; Russell Sinclair; digitised field data sheets to be delivered to the AEKOS TERN portal. added required V1 metadata in the AEKOS portal

 

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In the mid-1920's Professor Theodore George Bentley Osborn, Professor of Botany in the University of Adelaide, put forward strong scientific arguments concerning the lack of knowledge of the ecology of arid zone vegetation, and the effect of grazing on it. In 1925, a parcel of land of around 390 ha was identified in Koonamore Station in South Australia and fenced to exclude rabbits and other stock, and Mr Wilcox, one of the directors, had a three-roomed house erected to serve as a field laboratory. The area was originally referred to as the Arid Region Flora Reserve but later was named the TGB Osborn Vegetation Reserve after its founder. For simplicity it is commonly referred to as the Koonamore Vegetation Reserve. There have been some unwanted animal incursions over the years, but these have been rare. In 1931, for example, rabbits were able to enter due to fence damage. Kangaroos and emus are not fully excluded. As is clear from the objectives stated by TGB Osborn, the reserve was to provide the basis for systematic measurements of the now-protected vegetation. Osborn and his team (including Prof. J.G. Wood and Mr Terry Paltridge) set up a series of quadrats (square plots) and photopoints within the reserve. A series of transects was later added. All of the foregoing were permanently marked, and observations on species occurrence (presence and abundance) and physical measurements of the plants were made repeatedly, but at varying intervals. 

Method Summary:

Two of the outside populations were enclosed in triangular fences, one with sheep netting to protect from grazing by sheep, the other with both sheep and rabbit netting to protect against both sheep and rabbits. A third population was left unprotected. The population inside the Reserve was assumed to be protected from all grazing by the Reserve fence. The aim was to follow the fates of the original cohort.

• treatment 1. inside reserve
• treatment 2. outside-rabbit net
• treatment 3. outside-sheep net
• treatment 4. outside-unfenced.

Plants were given unique numbers, marked on roofing nails in the ground beside the plant. Attribute information about the data set  Ten measurements were made between 1997 and 2008. Measurements were not continued after 2008. Data recorded: measurement (visit) date, treatment number (1-4), Individual number, crown diameter north-south (cm), crown diameter east-west (cm), and height (cm) For detailed information please see the preview file in the data package, available under Access Data