Development of monitoring procedures for the herbaceous layer on the Northeastern Transvaal escarpment
作者:
M. Stalmans,
M.T. Mentis,
期刊:
African Journal of Range & Forage Science
(Taylor Available online 1993)
卷期:
Volume 10,
issue 3
页码: 129-134
ISSN:1022-0119
年代: 1993
DOI:10.1080/10220119.1993.9638339
出版商: Taylor & Francis Group
关键词: Replicate similarity;sourveld;wheel‐point apparatus
数据来源: Taylor
摘要:
A step‐wise approach was followed towards the design of a monitoring system for the herbaceous layer on the escarpment of the Drakensberg mountains in the Transvaal, South Africa. The parameter of concern was proportional species composition. In a first phase, the plot size and number of point observations required to achieve a repeatable assessment of a single plot at a predetermined precision level were investigated. The Chapman‐Richards three‐parameter model was fitted to similarity values obtained from comparisons between successively larger sets of points. This resulted in 140 points being required within a 30 × 30 m plot in order to recover 95% of the internal association of the composition data. In a second phase, the number of plots required for a repeatable assessment of a large stratum was determined. Successively larger nested areas were sampled. Monitoring of a large stratum at 95% of asymptotic replicate similarity would require sets of 21 randomly selected plots. The third and final phase was concerned with the development of a procedure for detecting change. A similarity test made it possible to detect change between successive surveys with a known degree of precision.
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