PROMOTING ACCESS TO AFRICAN RESEARCH

African Journal of Range and Forage Science

Log in or Register to get access to full text downloads.

Remember me or Register



DOWNLOAD FULL TEXT Open Access  DOWNLOAD FULL TEXT Subscription or Fee Access

Sampling efficiency for species composition assessments using the wheel-point method in a semi-arid savanna

BH Brockett

Abstract


A pilot survey to determine the sampling efficiency of the wheel-point method, using the nearest plant method, to assess species composition (using replicate similarity related to sampling intensity, and total sampling time) was conducted on three plot sizes (20 x 20m, 30 x 30m, 40 x 40m) at two sites in a semi-arid savanna. Total sampling time included the time to demarcate a plot. A 40 x 40m plot had the highest precision and repeatability (number of point observations required to achieve a stated asymptotic value), and was followed by a 20 x 20m plot. These relationships were consistent across sites. A 40 x 40m plot recorded the highest sampling times due to the time required to demarcate a plot. A 20 x 20m plot was the most efficient. A model to assist in making decisions regarding a suitable plot and sample size, and for planning and budgeting of vegetation monitoring programs was developed. Future surveys should include a Monte-Carlo data simulation as an adjunct to data collection.


Keywords: grass layer; plot size; point methods; replicate similarity; sample size


African Journal of Range & Forage Science 2001, 18(2&3): 93-101



http://dx.doi.org/10.2989/10220110109485761
AJOL African Journals Online