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Accueil du site → Projets de développement → Projets de recherche pour le Développement → Projets de Fondations (Ecologie) → Spatial Distribution of Woody Encroachment and its Effect on Ranging Ecology of African Lions in Southwest Serengeti

Kenya, Tanzania (2019)

Spatial Distribution of Woody Encroachment and its Effect on Ranging Ecology of African Lions in Southwest Serengeti

Ayoub Asenga

Titre : Spatial Distribution of Woody Encroachment and its Effect on Ranging Ecology of African Lions in Southwest Serengeti

Pays : Kenya, Tanzania
Zone d’intervention : Serengeti

Date : 8 Feb 2019

Bénéficiaire : Ayoub Asenga

Contexte  : Increasing woody vegetation cover is a threat to savannah ecosystems, particularly in southwest Serengeti. The observed transformation of the precious plain grasslands and open woodlands into dense woody dominated landscapes, could adversely affect the great biodiversity they once supported. Encroaching woody species are often thorny and/or unpalatable to herbivores, suppressing herbaceous plant cover, and thereby altering fundamental ecological processes and plant community structure. Although it is recognised as the most threatening form of rangeland degradation, little effort has been made to understand its spatiotemporal changes and the allied factors. This has hampered understanding and prediction of woody encroachment across the ecosystem by its ecological complexity

Description
The change in vegetation structure caused by wood encroachment interferes with predator-prey relationships, which play integral role in ecological regulation, influencing ecosystem function and stability. Increasing density of woody plants adversely reduces grass quantity and quality, which is an essential component in supporting prey animals for lions. Under the prey-abundance theory, it is expected that lions should prefer areas with high densities of their prey, which might be areas with open grasslands and high grass cover. In contrast, the ambush-cover hypothesis predicts that lions prefer habitats with greater cover (with dense vegetation) to enhance their predation success. Yet, these contradicting hypotheses are poorly understood with respect to woody encroachment. Besides that, expansion of bush encroachment adjacent to villages might have increased the lions’ hunting radius, exacerbating their interaction with human that regularly results into conflicts. With the use of Landsat satellite images from the year 1986 to 2018, we will quantify spatiotemporal land cover changes. The extent of woody encroachment will be correlated with selected influencing factors (soil types, fire regimes, average rainfall, waterways, drought index, and slopes). Three-year GPS collar data from lion prides will be used to investigate movement patterns and habitat preference of lions in different levels of woody encroachment. Additionally, we will conduct camera trapping surveys and line transect in different levels of encroachment to relate prey occurrence with ranging of lions.

The Rufford Foundation

Page publiée le 13 juin 2019