Research Repository :: Browsing by Author "Werema, Chacha"

Browsing by Author "Werema, Chacha"

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Effect of Habitat Fragmentation on Diversity and Abundance of Nesting Birds in an Urban Landscape: The Case of Mwalimu Nyerere Campus Thickets, University of Dar es Salaam, Tanzania
(College of Natural and Applied Sciences, 2017) Shirima, John D.; Werema, Chacha
Little is known of the nesting bird species in most of urban areas of East Africa. An investigation was made of the occurrence of breeding bird species in the fragmented thickets found in the Mwalimu Nyerere Campus of the University of Dar es Salaam, in the City of Dar es Salaam. The study examined how habitat fragmentation affects nesting bird species richness and diversity in the thickets. Systematic physical nest searches of breeding birds were conducted in the fragmented thickets. Searches were conducted in transects and they included inspecting vegetation, bare ground, cavities, stream (river) banks and other suitable nesting locations for the presence of active nests. Numbers and diversity of nesting bird species increased with fragment size which suggest that most nesting birds avoid smaller fragments and that reductions in size of habitat might negatively affect majority of the nesting bird species. For continued conservation of birds, protection of the remaining thicket fragments on the campus is recommended.
Effects of fire on understorey birds in Kimboza Forest Reserve in the eastern foothills of the Uluguru Mountains, Tanzania
(Wiley, 2014-09) Werema, Chacha
Fire is one of the main threats facing the long-term survival of the forests in the Eastern Arc Mountains. Yet, our understanding of how it affects fauna, particularly birds, is still poor. A fire that originated on surrounding farmland burned approximately half of Kimboza Forest Reserve between 13 and 15 October 2010. To better understand how birds respond to fire, a short-term study of understorey bird diversity and abundance in this forest reserve was conducted by comparing burned and unburned sites twenty months post-fire. Capture rates were significantly higher at the unburned site compared to the burned site. Bird species diversity was also higher at the unburned site than at the burned site. Despite the brevity of the study, the results suggest that fire has negative effects on forest avifauna and forest fires need to be prevented at Kimboza Forest Reserve as they affect the distribution and diversity of understorey birds.
evo12950-sup-0001-SuppMat
(2016-05) McEntee, Jay P.; Peñalba, Joshua V.; Werema, Chacha; Mulungu, Elia; Mbilinyi, Maneno; Moyer, David; Hansen, Louis A.; Fjeldså, Jon; Bowie, Rauri C. K.
Kimboza Forest Reserve, Tanzania: An important cold season refugium for altitudinal migrating birds
(Wiley, 2016-04) Werema, Chacha; Howell, Kim M.; Ndangalasi, Henry J.
Altitudinal migration of birds is defined as movements of individuals from higher to lower altitudes and vice versa due to different causes such as variations in food availability (Chaves-Campos, Arévalo & Araya, 2003; Boyle, 2010), changes in weather (Boyle, Norris & Guglielmo, 2010) or trade-offs between predation and survival (Boyle, 2008). Altitudinal migrations of birds have been reported to exist for most major mountain ranges of the world (Mcguire & Boyle, 2013). In Africa, altitudinal migration of birds has been documented by several authors (e.g. West Africa: Stuart, 1986; south-central Africa: Dowsett-Lemaire, 1989; Southern Africa: Oatley, 1982; Johnson & Maclean, 1994; East Africa: Stuart, 1983; Stuart et al., 1993; Burgess & Mlingwa, 2000; Werema, 2015a). Several studies have discussed the aspect of altitudinal migration of birds in the Eastern Arc Mountains (Stuart, 1983; Stuart et al., 1993; Burgess & Mlingwa, 2000; Werema, 2015a). However, relatively little is known for some areas, particularly in the isolated forest fragments that are found at the lower altitudes. This note presents findings on the effects of season on understorey bird assemblages in Kimboza Forest Reserve, an isolated forest fragment located about 12 km from Uluguru Mountains. The main emphasis is on the aspect of altitudinal migration because no quantitative studies on altitudinal migratory birds covering different seasons are available in this forest reserve
Preliminary observations on the avifauna of Ikokoto Forest, Udzungwa Mountains, Tanzania
(2013-05) Werema, Chacha; McEntee, Jay P.; Mulungu, Elia; Mbilinyi, Maneno
A study was conducted at c. 110 ha of Ikokoto forest using mist-netting and general field observations. Sixty-four species were recorded of which 61% were of conservation importance in terms of forest dependence. All species were found to belong to the familiar assembly of the large Udzungwa forests. Six species, the Green-throated Greenbul Andropadus fusciceps, Spot-throat Modulatrix stictigula, African Tailorbird Artisornis metopias, Black-lored Cisticola Cisticola nigriloris, Uhehe Fiscal Laniarius marwitzi and Fülleborn's Black Boubou Laniarius fuelleborni detected are restricted range and one species Moreau's Sunbird Nectarinia moreaui is nearthreatened according to IUCN threat status. The presence of many species which are forest dependent in this tiny forest indicates that this site, though small in size and highly fragmented, retains significant conservation value for birds.
Seasonal elevational movements of Eastern Olive Sunbird Cyanomitra olivacea in the Uluguru Mountains, Tanzania
(Taylor & Francis, 2016-05) Werema, Chacha
Little is known about the seasonal elevational movements for most tropical avifauna species. Seasonal elevational movements of the Eastern Olive Sunbird Cyanomitra olivacea were studied along an elevational gradient from 600 to 1 500 m above sea level in the Uluguru Mountains, Tanzania, between May 2005 and February 2006. The recapture of ringed individuals along an elevational gradient across seasons provided evidence for the seasonal elevational movement of the Eastern Olive Sunbird in the Uluguru Mountains and the first documented evidence for this species in the Eastern Arc Mountains as a whole. Due to forest fragmentation and lack of corridors connecting high- and low-altitude forests in the Uluguru Mountains, the results have implications for conservation of the forest along the entire elevational gradient as well as for other forest bird species that have been documented to make seasonal elevational movements in the Uluguru Mountains and the entire Eastern Arc Mountains.
Seasonal elevational movements of the Little Greenbul Andropadus virens in the Uluguru Mountains, Tanzania
(2014-11) Werema, Chacha
he little greenbul Andropadus virens Cassin 1858 is themost common and ubiquitous forest greenbul in Africa(Keith, Urban & Fry, 1992). In East Africa, it is mainlyfound in lowland forests, especially in edges, secondarygrowth and moist thickets (Britton, 1980). It is anunderstorey species mainly feeding on fruits, and occa-sionally, it forages on insects (Keith, Urban & Fry, 1992). Ithas been detected crossing forest gaps in the East Usam-bara mountains (Korfanta, Newmark & Kauffman, 2012).In their reviews of forest birds and seasonal elevationalmovements in the Eastern Arc mountains, Stuart et al.(1993) and Burgess & Mlingwa (2000) make no mentionof a seasonal elevational movement by the little greenbul.However, based on differences in capture rates of littlegreenbul between seasons, with cold season having highercapture rates, its seasonal elevational movements havebeen suspected by Stuart (1983) and Cordeiro et al. (2006)in the East Usambara and Udzungwa mountains, respec-tively. Nevertheless, our understanding of the seasonalmigratory status of the little greenbul is poor andunequivocal evidence for seasonal elevational movementof the little greenbul based on the recapture of ringedindividuals is nonexistent. In this note, I provide evidencefor seasonal elevational movement of the little greenbul inthe Uluguru mountains in central Tanzania.
Seasonal variation in diversity and abundance of understorey birds in Bunduki Forest Reserve, Tanzania: evaluating the conservation value of a plantation forest
(Taylor & Francis, 2015-12) Werema, Chacha; Howell, Kim M.
Plantation forests generally support lower bird diversity than natural forests. However, in some instances the plantations have been found to provide suitable habitat for a number of bird species. In the Eastern Arc Mountains, there is limited knowledge how understorey birds, some of which make seasonal altitudinal movements, use plantations. Using mist netting we assessed seasonal use of the plantation forest by the understorey bird community in Bunduki Forest Reserve in the Uluguru Mountains. Species diversity and capture rates were significantly higher during the cold season than during the hot season possibly due to seasonal altitudinal migration by some species. The use of plantations by those species that make seasonal altitudinal movements shows that plantation forests can enhance indigenous biodiversity by enabling connectivity between two or more natural forest patches. Our findings suggest that in a situation where there is no natural forest, an exotic plantation with suitable indigenous understorey cover can help in protection of birds, including endemic and near-endemic species.
Seasonal variation in understorey bird species diversity and abundance in the Uluguru Nature Reserve, Tanzania
(2015-02) Werema, Chacha
The Uluguru Mountains form a component block of the Eastern Arc Mountains of Tanzania and Kenya and are known for a high degree of endemic vertebrate and plant taxa. Among the Eastern Arc Mountains, the Uluguru Mountains rank second in the number of endemic species. Although the forests in these mountains have received considerable ornithological attention, studies on how forest bird communities in the available low elevation forests are affected by seasons remain patchy and sporadic. Such studies are important because in the Uluguru Mountains, forest destruction in the lower slopes has been severe to an extent that there is very little substantial forest survives below 900 m above sea level. Using mist netting, seasonal variation in understorey bird communities in the remaining low elevation forests in the Uluguru Nature Reserve was assessed between 2005 and 2011. Species diversity and relative abundance of the birds were higher during the cold season in comparison with the hot season possibly due to seasonal elevational movements of some species. Elevational migrants made a large proportion of the avifauna in the study area. The results suggest that low altitude forests are important cold season refugia of elevational migrants
Social selection parapatry in an Afrotropical sunbird
(Wiley, 2016-05) McEntee, Jay P.; Peñalba, Joshua V.; Werema, Chacha; Mulungu, Elia; Mbilinyi, Maneno; Moyer, David; Hansen, Louis A.; Fjeldså, Jon; Bowie, Rauri C. K.
The extent of range overlap of incipient and recent species depends on the type and magnitude of phenotypic divergence that separates them, and the consequences of phenotypic divergence on their interactions. Signal divergence by social selection likely initiates many speciation events, but may yield niche-conserved lineages predisposed to limit each others' ranges via ecological competition. Here we examine this neglected aspect of social selection speciation theory in relation to the discovery of a non-ecotonal species border between sunbirds. We find that Nectarinia moreaui and N. fuelleborni meet in a ∼6 km wide contact zone, as estimated by molecular cline analysis. These species exploit similar bioclimatic niches, but sing highly divergent learned songs, consistent with divergence by social selection. Cline analyses suggest that within-species stabilizing social selection on song-learning predispositions maintains species differences in song despite both hybridization and cultural transmission. We conclude that ecological competition between moreaui and fuelleborni contributes to the stabilization of the species border, but that ecological competition acts in conjunction with reproductive interference. The evolutionary maintenance of learned song differences in a hybrid zone recommend this study system for future studies on the mechanisms of learned song divergence and its role in speciation. This article is protected by copyright. All rights reserved.

Browsing by Author "Werema, Chacha"

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