Browsing by Author "Nkwabi, Ally Kiyenze"

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    Influence of seasonal habitat variation and agriculture on abundance, diversity and breeding of birds in Serengeti national park and surrounding areas, Tanzania.
    (University of Dar es Salaam, 2017) Nkwabi, Ally Kiyenze
    Assessment of how bird communities differ in abundance, diversity and breeding patterns as a result of variation in habitat structure inside the park and in agricultural areas was conducted between February 2010 and April 2012. Environmental factors like rainfall, food and nesting materials were used to investigate whether they affect the breeding seasons of bird species in the study area. With increasing human populations surrounding the protected area it is necessary to understand their impacts on the ecosystem by studying habitat modification caused by agriculture. To document this, it was necessary to examine first the impacts of natural changes such as those from current seasonal variation in habitat present within the Serengeti National Park and surrounding areas as a baseline to compare with changes imposed by humans in areas adjacent to the park. A total of 40 plots of 100 m x 100 m and six transects were established, total counts were used to collect birds’ data inside and outside Serengeti National Park. The results show that Acacia tortilis woodland had higher bird species richness with 102 species compared to Commiphora habitat with 66 species and A. robusta habitat with 59 species. Ground feeding birds were more abundant and diverse in Commiphora dominated habitat, indicating that vegetation was the determinant of the physical structure of the environment influencing distributions and abundance of bird species. On the other hand, rainfall determined the peak of breeding of birds except for frugivores which bred throughout the year. In addition, availability of food, nesting material and nesting location also determined the breeding seasons of birds in the Serengeti National Park. Birds in high trophic level especially birds of prey were affected by agricultural activities outside the Serengeti National Park, whereas insectivorous and herbivorous birds were not affected by agricultural activities, indicating that bird species that fed on vertebrates were less able to tolerate human disturbances. Habitat structure, environmental factors and human activities contribute to a great deal on the composition, distribution and abundance of birds.
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    Influence of wildfire on the avian community of the Serengeti National Park, Tanzania
    (University of Dar es Salaam, 2007) Nkwabi, Ally Kiyenze
    This study investigated the influence of disturbance produced by wildfire on the avian community of the Serengeti National Park, Tanzania between May 2004 and January 2005. Avifauna was counted using a standard “point count” method in three vegetation types, namely long grass plains, Acacia and Terminalia woodlands. Analyses were made on species richness and abundance of avifauna. A total of 120 species in 77 genera, 41 families and 13 orders of ground feeding avifauna were recorded, of which 92 were insectivorous and 28 were either granivorous or frugivorous. The rarefaction curve showed an increase of avifauna species richness and abundance from 43 species in unbumt areas to 65 species in burnt long grass areas. In Acacia woodlands, a total of 110 species were recorded in unbumt areas while 107 species recorded in burnt areas. Also, 87 species in unbumt areas and 85 species in burnt areas were recorded in Terminalia woodlands. Avifauna species richness and abundance in Acacia and Terminalia woodlands were not influenced with burning activities. The Somali short-toed lark (Calandrella Somalica), rattling cisticola (Cisticola chiniana), Tabora cisticola (Cisticola angusticauda) slate- coloured boubou (Laniarius funebris) and tawny-flanked prinia (Prinia sub/lava) were found to be prevalent and widely distributed in unbumt areas whereas, Fischer’s sparrow-lark (Eremopterix leucopareia), red-capped lark (Calandrella cinerea) and helmeted guineafowl (Numida meleagris) were restricted in burnt areas. Insect food supply was not an important environmental factor affecting the species richness and abundance of insectivorous avifauna. This study recommends conservation of avifauna habitats by implementing prescribed burning and reducing late burning for preservation of grassland avifauna.