The development of veld assessment in the Northern Transvaal savanna I. Red Turfveld.

Grazing-induced gradients in pasture species composition were characterised for the red turfveld of the Northern Transvaal savanna. A proposed classification of pasture species response to grazing was develop and the influence of state variables and driving forces other than grazing was recognized. It is argued that the present status of woody vegetation reflects a variety of influences on a variety of scales. Its effect on forage production needs quantification. Relationships between a pasture composition index and the density of "tree equivalents" were demonstrated. Differences in fire history, soil type and/or grazing may have accounted for the occurrence of two distinct regressions. "Condition" indices incorporate the assumption that grazing is the only force acting on the veld apart from season, and their value is questioned. Discussion of benchmarks is left to Part II. There was no evidence of soil change as a consequence of grazing but the importance of soil type in vegetation assessment was noted. Pasture yield was not investigated but deserves study. Gaps in knowledge are discussed and some recommendations for research are offered.Keywords: botany; disturbance history; driving forces; forage production; grazing; northern transvaal; pasture; pasture index; red turfveld; savanna; soil assessment; south africa; species classification; status; veld; veld assessment; woody vegetation; yiel