The impact of habitat fragmentation on tsetse abundance on the plateau of eastern Zambia

Abstract

Tsetse-transmitted human or livestock trypanosomiasis is one of the major constraints to rural development in sub-Saharan Africa. The epidemiology of the disease is determined largely by tsetse fly density. A major factor, contributing to tsetse population density is the availability of suitable habitat. In large parts of Africa, encroachment of people and their livestock resulted in a destruction and fragmentation of such suitable habitat. To determine the effect of habitat change on tsetse density a study was initiated in a tsetse-infested zone of eastern Zambia. The study area represents a gradient of habitat change, starting from a zone with high levels of habitat destruction and ending in an area where livestock and people are almost absent. To determine the distribution and density of the fly, tsetse surveys were conducted throughout the study area in the dry and in the rainy season. Landsat ETM+ imagery covering the study area were classified into four land cover classes (munga, miombo, agriculture and settlements) and two auxiliary spectral classes (clouds and shadow) using a Gaussian Maximum Likelihood Classifier. The classes were regrouped into natural vegetation and agricultural zone. The binary images were overlaid with hexagons to obtain the spatial spectrum of spatial pattern. Hexagonal coverage was selected because of its compact and regular form. To identify scale-specific spatial patterns and associated entomological phenomena, the size of the hexagonal coverage was varied (250 and 500 m). Per coverage, total class area, mean patch size, number of patches and patch size standard deviation were used as fragmentation indices. Based on the fragmentation index values, the study zone was classified using a Partitioning Around Mediods (PAM) method. The number of classes was determined using the Wilks’ lambda coefficient. To determine the impact of habitat fragmentation on tsetse abundance, the correlation between the fragmentation indices and the index of apparent density of the flies was determined and habitat changes most affecting tsetse abundance was identified. From this it followed that there is a clear relationship between habitat fragmentation and the abundance of tsetse flies. Heavily fragmented areas have lower numbers of tsetse flies, but when the fragmentation of natural vegetation decreases, the number of tsetse flies increases following a sigmoidal-like curve.

Trypanosomiaisis in Non Migratory Cattle in Suburban Kaduna

“…An area where farming and human settlements are presentgreatly reduces vector (tsetse fly) population(thereby the possibility of infection) due to thefragmentation of their habitat (Ducheyne et al,2009). Treks have been demonstrated to significantly increase the risk of contracting trypanosome infections (Majekodunmi et al, 2013).…”

Shifting from wild to domestic hosts: The effect on the transmission of Trypanosoma congolense to tsetse flies

“…In tsetse habitat highly fragmented by agricultural activities, tsetse flies are less abundant Ducheyne et al, 2009) but also more infected (personal observations from Zambia). Simukoko (2007) also reported, in Zambia, high trypanosomosis incidence in livestock despite a relatively low tsetse abundance.…”

Transmission Dynamics of Rhodesian Sleeping Sickness at the Interface of Wildlife and Livestock Areas

“…Abundance, Distribution, and Mortality On a regional scale, a general reduction in investment in large-scale tsetse control since the 1980s [44] has been balanced against loss of tsetse habitat for agricultural expansion [45][46][47][48]. This has led to an overall decline in habitat suitable for tsetse.…”