Aspekte rakende die ruimtelike ekologie van die rooijakkals (Canis mesomelas) as probleemdier in die Suid-Vrystaat

[摘要] English: According to the Red Meat Producers' Organisation, damage-causing predators annually catch small stock to a value of approximately R1,1 billion in South Africa. On most of the small stock farms in the Southern Free State, black-backed jackals, Canis mesomelas, are shot on sight and actively hunted to provide a safe environment for domesticated animals. The veld and habitats previously occupied by natural prey for these carnivores are now used for commercial farming practices. Carnivores are conserved in established formal protection and conservation areas within the ecosystem to lessen their contact with small stock. In South Africa the black-backed jackal successfully adapts to this farming environment with visible adaptation patterns. These behavioural patterns are influenced by the circumstances of the animal and variables within its environment. In the study area these fixed patterns of the black-backed jackal presumably annually repeat itself. This study researched these behavioural patterns of the jackal. For the first time, geographic information systems (GIS) are used in the research of the black-backed jackal. Since 2006, black-backed jackal regional data (of all jackals killed during hunting operations) was collected in a high depredation area in the Southern Free State. Data points collected from 1927 to 2009 were accordingly entered on electronic charts in ArcView. The total number of data points were obtained from 433 black-backed jackals killed, with the localities of 344 charted. The data is grouped into four sets: the first set, collected over 26 years, 1927 to 1953, consisted of 15 black-backed jackals; the second set, collected over 5 years, 1993 to 1997, consisted of 124 black-backed jackals; the third set, collected from 1999 to 2008, 10 years, consisted of 210 black-backed jackals; and the fourth set, from 2006 to 2009, four years, had a total of 84 black-backed jackals. Therefore, the number of black-backed jackals killed significantly increased, from 15 killed the first 26 years, to 418 over the last 16 years, within the same specific area. The increase in numbers of black-backed jackals removed from the area is used as indication of the increase in damage over the years in the study area. The average mass of 68 males, killed between 1993 and 1997, was 7.15kg and 63 females, 6.72kg. According to the 35 farmers in this specific area of the Southern Free State, the jackal problem is at present more under control than 30 years ago, which also applies to some other parts of the Southern Free State and South Africa. The reason for this can be ascribed to a better understanding of the animals and planning of hunting expeditions. In the late 1980's, the average loss per farmer was ± 200 sheep per annum. At present, about 40 sheep on average are lost per farmer. The aim of this study is to further alleviate the damage-causing problem in the study area by making accurate predictions and planning to decrease losses. In the study area, peak losses are noted annually from August to October and March to May. The black-backed jackals mainly follow certain fixed movement patterns in the study area and breeding pairs seemingly react to the same stimuli from their direct environment. The same dens are repeatedly used and there is a clear relationship between the location of the dens and human activities. When a breeding pair is removed from an area, a new breeding pair will soon establish there. The processing of historic data leads to predictions on where the black-backed jackals will establish, where they will breed and where they will probably cause damage. It also predicts where they can probably be caught. This study shows a strong correlation between the physical nature of the environment and the black-backed jackals.

[发布机构] University of the Free State