Spatio-Temporal Effects of Land Use Changes in A Savanna Wildlife Area of Kenya
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Land use changes have been shown to have significant effects on wildlife species. Sixty three percent of the national Parks and Reserves in Kenya are located in the savannas. Because of the seasonality associated with savanna ecosystems, 75% of the wildlife species and numbers in Kenya occur in savanna nonpark areas. Therefore, conservation of wildlife in Kenya has to address the changes that are taking place in savanna areas outside parks. I studied land use changes and their effects on elephant habitat quality in Amboseli Basin, Kenya. I used visual interpretation to analyze land use changes from satellite images for 1975, 1988, and 1993. I determined that during the evaluation period, conversion of areas to agricultural land has been unidirectional. The hectarage under cultivation was 2,937, 10,950, and 24,476 for 1975, 1988, and 1993 respectively. Trend analysis seems to suggest that during the evaluation period, conversion of areas to agricultural land has followed an exponential function (R2 = 0.99) in Amboseli Basin. The area under cultivation was 6.9% of the total area studied. This is small but significant considering that agricultural land was almost exclusively located in areas that form the dry season fall back areas. Such areas are important for the survival of elephants and other species during critical periods.
I developed a dry season habitat suitability index (HSI) model for the African elephant based on the density of acacia trees (# of trees > 5 cm dbh/ha) and distance (km) to natural sources of water in the basin. The amount of good quality habitat (i.e., HSI > 0.6) declined from 74,666 ha in 1975 to 54,890 ha in 1988, to 23,208 ha in 1993. This is a drop of 51,890 ha (65.5%) of good quality habitat in the basin. On the other hand, low quality habitat (HSI < 0.2) increased by 272% between 1975 and 1993. The weighted HSI values in the basin showed a decline, as did the habitat units for the 3 evaluation years. The weighted HSI declined by 0.13 between 1975 and 1993, while the total habitat units (ha) declined by 40,567 ha during the 18 year period. It appears that elephant habitat quality has steadily declined in the Amboseli Basin during the period considered in this study.
The use of nonpark areas by elephants leads to direct interaction and conflicts with humans. Between June 1996 and July 1997, I recorded a total of 489 elephant damage incidents while the Amboseli National Park authorities recorded 143. The damage types were crops, livestock deaths, and human deaths and injuries. The majority of the damage cases involved crop depredation. The Amboseli National Park authorities significantly under-reported the number of elephant damage incidents in the basin (P < 0.0001).
- Doctoral Dissertations