The University of Adelaide - Senna Populations, Koonamore Vegetation Monitoring Project

The TGB Osborn Vegetation Reserve (or Koonamore Vegetation Reserve (KVR)) is a protected area on Koonamore Station which has been fenced off from grazing since the mid 1920's. In 1925, Professor Theodore George Bentley (TGB) Osborn and his colleagues established a vegetation reserve by fencing off 400 ha of a badly overgrazed portion of the Koonamore station to study the process of recovery of vegetation in the arid zone of South Australia after the removal of grazing pressure. The fence was established to initially keep sheep and later also rabbits from the reserve and allow vegetation regeneration. The resulting long-term vegetation monitoring project at Koonamore is now over 80 years old, making it one of the longest-running monitoring series of its type in the world.; Reserve History: In the mid 1920's Professor TGB Osborn and his colleagues extended their interests in ecology and field physiology of vegetation to the arid zone of South Australia. In 1892 Dixon had warned the Royal Society of South Australia of serious degradation of the soils and vegetation resulting from pastoralism and other alien influences in the region. Equally important to the origin of KVR was the new theory of vegetation succession derived from North American work early in the century. Osborn was particularly concerned with the question as to whether overgrazing by domestic and feral herbivores would result in return of the original vegetation via recognisable 'seral' stages, or whether the changes were ?artificial, mere destructions and as such outside the ecologist's proper field?. Although the concepts of 'succession' and the scope of ecology have developed and changed much since that time, nevertheless it was interest in 'succession to climax' that gave the initial impetus to KVR and many other long-term vegetation studies from that time. The theory of vegetation succession gave rise to the permanent charted quadrat as a technique for observing vegetation change. An extensive series of permanent quadrats was set up on KVR and supplemented by a series of fixed photopoints, in order to pursue the first aim. Although some of these were allowed to lapse within five years, many others were sampled more or less regularly, some almost annually up to the present. Several early publications reviewing the progress of vegetation change resulted. Nothing was done towards the second aim but autecological and population dynamics studies are still being carried out, based on KVR and its records. The Bibliography contains a complete listing of research publications arising from work done on the Reserve. Much of the continuity of the earlier records is due to the efforts of Miss Constance Eardley, who while a lecturer in the Department of Botany, organised annual visits of students and staff to take records and maintain KVR. However, after 1950 the rate of sampling had begun to decline and in the mid 1960's ceased altogether for a period of several years. In the 1970's Dr Russell Sinclair reactivated the recording programme and also began a sustained effort at rabbit control. Although the Reserve was originally fenced with rabbit-proof netting, the rabbits were never eradicated and the population has fluctuated greatly with the seasons. Beginning in 1975, numbers have been kept very low by careful annual inspection and control. Since that time there has been marked seedling establishment of several tree and shrub species which showed little previous regeneration. The Reserve records now contain a history of the vegetation over 50 years without sheep grazing followed by over 30 years without significant grazing by either sheep or rabbits. Kangaroos and emus have never been excluded from the Reserve, as they can jump the fence, and their numbers vary with the seasons. The monitoring work at KVR and the curation of its records is continuing under the direction of Dr Sinclair. The Reserve is also used for post-graduate study and complements the arid-zone research interests of Environmental Biology at the Middleback Field Sation near Whyalla.; Site Description: The Reserve is located in the centre of Koonamore Station, a sheep-grazing lease 400 km north-east of Adelaide, South Australia (Lat. 32º07'S, Long. 139º20'E) in predominantly chenopod shrubland with mean annual rainfall of about 200mm. The area consists of a complex of low sand dunes alternating with sand plain and harder loam soils with travertine limestone on the intervening flats. The tree cover is a low open woodland formation. The sand dunes carry Acacia aneura (mulga), A. burkittii and Eremophila spp., the sand plain a dense stand of Casuarina pauper (blackoak, belah), and the harder loam soils a mixed community of Myoporum platycarpum (false sandalwood) and Alectryon oleifolius (bullock bush, rosewood). Understorey shrubs, which also form low chenopod shrubland communities in some areas, include Atriplex vesicaria (bladder saltbush), A. stipitata and Maireana sedifolia (bluebush). Numerous other chenopodiaceous shrubs also occur, and grass and ephemeral herb cover varies with the seasons. Several species of Senna, Eremophila and other shrubs also occur.; Monitoring activities: Some or all of the following monitoring activities are carried out during visits to the TGB Osborn Vegetation Reserve: Vegetation Quadrats, Photopoints, Senna Quadrat (Cassia Corner), Myoporum platycarpum Plants, Saltbush Transects, Senna Populations, Kangaroo Transects, Rabbit Activity Monitoring and Control.; Senna Populations: Many very young Senna seedlings were identified close to the Northern boundary of the TGB Osborn Vegetation Reserve, both inside and outside of the reserve in 1997. 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, i.e. on the reserve. Different fencing treatments were applied to the plants outside the reserve fence. One was protected from sheep, the second from both sheep and rabbits, the third left unprotected. The population inside the reserve was assumed to be protected from all grazing by the reserve fence. Plants were given numbers, marked on roofing nails in the ground beside the plant, and mapped on chart cards.

TGB奥斯本植被保护区（又称库纳莫尔植被保护区（KVR））是库纳莫尔牧场的一片受保护区域，自20世纪20年代中期起就已围栏禁牧。1925年，西奥多·乔治·本特利（TGB）·奥斯本教授及其同事在库纳莫尔牧场一片严重过牧的区域围栏划定400公顷土地，建立了该植被保护区，旨在研究南澳大利亚干旱区解除放牧压力后的植被恢复过程。围栏最初用于阻挡绵羊，后来也用于防兔，以促进植被再生。由此形成的库纳莫尔长期植被监测项目至今已逾80年，使其成为全球同类监测中持续时间最长的项目之一。

### 保护区历史
20世纪20年代中期，TGB奥斯本教授及其同事将研究兴趣拓展至南澳大利亚干旱区的植被生态学与野外生理学领域。1892年，迪克森曾向澳大利亚皇家学会警示，该区域的畜牧业（pastoralism）及其他外来影响已导致土壤和植被严重退化。对KVR起源同样关键的是20世纪初源自北美的植被演替新理论。奥斯本尤为关注的核心问题是：家养及野生食草动物过牧后，植被是否会通过可识别的“演替系列”阶段恢复原貌，抑或这些变化属于“人为破坏，不在生态学家研究范畴内”？尽管自那时起“演替”概念及生态学研究范围已发生诸多发展与变革，但正是对“向顶极群落演替”的探索，为KVR及当时众多长期植被研究提供了最初动力。

植被演替理论催生了永久样方绘图技术（permanent charted quadrat），用于观测植被变化。为实现首个研究目标，KVR设立了大量永久样方（permanent quadrats），并辅以固定摄影点（fixed photopoints）系列。尽管部分样方在五年内停止观测，但多数样方的采样工作保持规律，部分甚至直至今日仍几乎每年开展。早期发表了若干综述植被变化进展的论文。第二个目标未采取行动，但基于KVR记录的植物生态学（autecological）和种群动态研究仍在持续。参考文献包含该保护区研究产生的全部出版物清单。

早期记录的连续性很大程度上归功于康斯坦斯·厄德利小姐的努力，她在植物学系任教期间组织师生年度访问以维护KVR并记录数据。然而1950年后采样频率下降，20世纪60年代中期曾完全停滞数年。20世纪70年代，拉塞尔·辛克莱博士重启记录项目并开展持续兔害控制。尽管保护区最初采用防兔网围栏，但兔子从未被根除，种群数量随季节波动显著。1975年起，通过年度检查与控制，兔子数量维持在极低水平，此后若干此前几乎无再生的乔灌木物种出现显著幼苗定植。保护区记录如今涵盖50余年无绵羊放牧、后续30余年无绵羊或兔子显著放牧的植被历史。袋鼠和鸸鹋因可跃过围栏未被排除，数量随季节变化。KVR的监测与记录管理在辛克莱博士指导下持续进行，同时用于研究生学习，并与怀阿拉附近Middleback野外站的环境生物学干旱区研究形成互补。

### 站点描述
保护区位于库纳莫尔牧场中心（南澳大利亚阿德莱德东北400公里，南纬32°07′，东经139°20′），属藜科灌木（chenopod shrubland）区，年均降雨量约200毫米。区域由低矮沙丘、沙原及硬质壤土交替构成，中间平地上分布钙华石灰岩（travertine limestone）。树木覆盖为低矮开阔林地形态（low open woodland formation）：沙丘生长密金合欢（Acacia aneura）、伯克氏金合欢（A. burkittii）及沙生植物属（Eremophila spp.）；沙原分布密集的pauper木麻黄（Casuarina pauper）；硬质壤土为宽果水芫花（Myoporum platycarpum）与油叶麦珠子（Alectryon oleifolius）的混合群落。下层灌木（部分区域形成低矮藜科灌丛）包括囊状滨藜（Atriplex vesicaria）、柄滨藜（A. stipitata）及蓝灌木（Maireana sedifolia），另有多种其他藜科灌木，草本和短命植物覆盖随季节变化。若干决明属（Senna）、沙生植物属及其他灌木物种亦有分布。

### 监测活动
访问TGB奥斯本植被保护区期间开展的监测活动包括（部分或全部）：植被样方（quadrats）、摄影点（photopoints）、决明属样方（Cassia Corner）、宽果水芫花植株监测、滨藜样带（Saltbush Transects）、决明属种群监测、袋鼠样带（Kangaroo Transects）、兔活动监测与控制。

### 决明属种群
1997年在保护区北部边界附近发现大量年幼决明属幼苗（分布于内外两侧）。为研究保护区外放牧对幼苗的影响，在围栏北侧确定并测量三个种群，南侧（保护区内）确定第四个种群。对保护区外植株采用不同围栏处理：一组防绵羊、一组防绵羊与兔子、一组无保护；保护区内种群假定受围栏保护免受所有放牧影响。植株被编号并标记在旁侧屋顶钉上，同时在图表卡上绘图。