The use of fractals to assess the ecological impact of increased cattle population: case study from the Runde Communal Land, Zimbabwe.
Abstract
A methodology that mathematically measures the stability of patches of vegetation identified from remotely sensed data is presented. The methodology was applied to a sequence of aerial photographs of the Runde Communal Land taken in 1968, 1975, 1980 and 1985. For both patches of grass and densely wooded areas, the data showed a pattern of continuous disintegration, with larger patches being broken down into smaller patches over time or disappearing entirely. The number of grass patches increased from 24 in 1968 to 71 in 1985; total area of grass patches increased by 16% during this period, while the area of densely wooded patches decreased by 69%. The stability of patches was related to their size. On average, increasing cattle numbers resulted in decreasing stability over time, but small grassland patches remained stable despite a 50% growth in cattle population.