Remote sensing of the link between arable field and elephant (Loxodonta africana) distribution change along a tsetse eradication gradient in the Zambezi valley, Zimbabwe

Abstract

We investigated whether the proportion of remotely sensed arable fields increased along a tsetse eradication gradient in the Sebungwe region. We also investigated whether and to what extent this increase in arable fields affected the distribution of the African elephant (Loxodonta africana) between the 1980s and 1990s. Results showed a relatively higher increase in the proportion of arable fields in the zone cleared of tsetse by 1986 compared to the zone that was still tsetse infested by the same date. Results also showed contrasting patterns in the relationship between the proportion of the habitat under arable fields and elephant distribution between the two periods. Specifically, in the 1980s, when arable field cover was between 0% and 11%, there was a weak (p>0.05) positive relationship between elephant presence and the proportion of the habitat under arable fields. In contrast, a significant (p<0.05) negative relationship emerged in the 1990s, when arable field cover ranged between 0% and 88%. Furthermore, the results demonstrated that the change in the probability of elephant presence between the early 1980s and the early 1990s was significantly (p<0.05) related to the change in the proportion arable fields. In conclusion, this study demonstrated that the expansion of arable fields in the Sebungwe was greater in areas where tsetse had been eradicated compared with areas that were still tsetse infested. Overall, the results suggest that using remotely sensed data, we can conclude that tsetse eradication led to the redistribution of elephants in response to arable field expansion.