Date of Award:

1973

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Natural Resources

Department name when degree awarded

Wildlife Science

Advisor/Chair:

Frederic H. Wagner

Abstract

A study of habitat selection by large wild ungulates was carried out on a 50 cm2 area in the sub-tropical Lowveld region of eastern Transvaal province, South Africa. Estimations were made of herbaceous forage net productivity and ungulate secondary productivity on the same area.

Fourteen vegetation types, varying in composition and structure from open savanna to dense woodland, were delineated by association analysis. Structural and vegetational characteristics which were considered to influence ungulate distribution were measured within each vegetation type.

The study area supported resident populations of seven ungulate species during the wet season; drv season densities were higher due to population influxes from surrounding areas. Densities ranged from 13 to 67 animals per km2, with impala making up from 40 to 70 percent of the total population, wildebeest 10 to 40 percent, and lesser proportions of giraffe, zebra, kudu, warthog and waterbuck. Savanna vegetation types supported total densities of up to 185 animals/km2, while wooded types support fewer animals.

Waterbuck were the most selective of the ungulates and concentrated mainly in the riparian woodland. Wildebeest, zebra and giraffe made variable use of savanna and open woodland types. Warthog preferred savanna types and avoided woodland. Impala were less selective, and kudu showed no habitat preferences. Ungulate distribution was related to several habitat characteristics, and the key factors were found to differ in each case. Each species had a unique combination of habitat characteristics to which it responded in linear fashion, and this was considered to be the way in which ungulates avoided competition by achieving spatial separation.

Herbaceous forage standing crops and net production were functions of vegetation composition, soil types, rainfall and extent of ungulate utilization. Standing crops ranged from 350 to 4104 kgs/ha air-dried forage. Net primary production ranged from zero to 2719 kgs/ha; vegetation types on sandy soils did not produce in years with poor precipitation. Ungulates consumed about one-fourth of the herbaceous net primary production during the wet season and more than four-fifths during the course of a full year.

Ungulate biomass on the area averaged about 40 kg/ha during the wet season and 65 kg/ha in the dry season, but biomasses varied a great deal with vegetation type, ungulate population species coMposition and seasonal densities. Ungulate secondary product ion varied correspondingly and ranged from 1.3 x 10-3 kcal/m2 per day to 4.8 x 10-3 kcals/m2 per day. Overall secondary production rate for the 2-year study period was 0.97 kcals/m2 per year, produced from a mean standing crop of 7.46 kcal/m2.

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