Bird diversity and distribution in relation to landscape types in Musanze City, Northern Rwanda

Abstract

A large number of wildlife survives outside protected areas on farmlands, pasturelands, and urban areas. Among all faunas, birds are one of most present wild animals in cities. Birds fulfill many ecological functions in their habitats, playing an important role in seed dispersal of fleshy fruit-producing plants. The landscape of the Musanze District has been undergoing major changes due to rapid urbanization driven by a fast growing human population. To ensure that bird-provided ecosystem services in Musanze City, Rwanda, are enjoyed by communities at an appropriate level for both current and next generation, a study of the effect of urban fabric lay out on its bird diversity and distribution was conducted. Linear mixed models (LMM) were used to assess whether landscape types have an effect on bird abundance and diversity. The Shannon‟s diversity index was used to identify the diversity of bird species in Musanze City. One Albertine Rift endemic bird species, the Ruwenzori double-collared sunbird (Cinnyris stuhlmanni) was recorded. Three migratory birds were found in Musanze City for the first time: the Common Sandpiper (Actitis hypoleucos), the Spotted Flycatcher (Muscicapa striata) and the Willow Warbler (Phylloscopus trochilus). Two bird species have not been previously reported in Rwanda: the Garden Warbler (Sylvia borin) and the Lesser Spotted Eagle (Aquila pomarina). An effect of city landscape types on the bird richness and relative abundance was also highlighted; residential neighborhood, institutional grounds and informal settlements were found to have highest species diversity indices compared to the rest of micro-landscape types. Riverside emerged as the landscape type with a specialized bird fauna, which are known to be restricted to the wetland environment. However, as a whole, built-up and open field categories had comparable results. Scavengers appeared to contribute more to biomass recycling than any other bird category. This study should help urban decision makers take into account the existence of a great diversity of avian fauna when developing and implementing land use plans, especially when villages and cities are in proximity of protected areas or natural reserves. Botanical gardens and public parks should be included in the master plan of the City.