Browsing by Author "Magige, Flora J."
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Item Abundance and Diversity of Rodents at The Human-Wildlife Interface in Western Serengeti, Tanzania. African Journal of Ecology(Wiley, 2006-07) Magige, Flora J.; Senzota, R. B. M.In this paper we examine how climate change interacts with other disturbances to alter the functioning of a tropical ecosystem, the Serengeti in Tanzania. Tropical Africa has increasing temperatures and changes in rainfall. Long-term data have shown how the avifauna responds to the interaction of environmental change with other disturbances: (1) habitat modification through agriculture by limiting endemic species and top trophic levels. Rare species are lost so this is a problem for conservation. Top trophic levels are lost and the lack of predators then releases pests. This is a problem for natural resource management. (2) Disease and hunting cause slow change in the species complex. This can alter community dynamics depending on which species enter or leave. (3) Habitat fragmentation or decay can cause slow change. When this reaches a threshold there may be rapid change in the species composition causing multiple states. One lesson is that present-day ecosystem states and trends can only be understood in the context of past historical events. Another is that all systems change so this requires a new approach to conservation. Within protected areas, new boundaries or new areas will be required. Outside rewilding is required to support more biodiversity.Item Breeding Biology Of Ostriches (Struthio Camelus) In The Serengeti Ecosystem, Tanzania(Wiley, 2009-03) Magige, Flora J.; Stokke, Bård G.; Røskaft, EivinOstrich breeding behaviour in the Serengeti ecosystem, Tanzania was investigated for differences in laying dates between low altitude western area (WA) and high altitude eastern area (EA) populations. Ostriches in WA laid eggs significantly earlier than in EA. The differences could be attributed to topography and rainfall pattern. Reliable rains in lower altitudes ensure availability of food that in turn influences the whole process of the reproductive cycle. Clutches were contributed by several females with a nest having up to 38 eggs. We also compared the frequency of observation of predators, ostriches, nests, 'singletons' (single eggs laid randomly) and broods between the two areas. There was no significant difference between WA and EA in 1) ostrich/nest ratio, indicating similar breeding densities; 2) ostrich/predator and predator/nest ratios, indicating that predation pressure was equally high; 3) nest/singleton and predator/singleton ratios, indicating that loss of nests did not vary between areas. However, there were significantly more predators, nests and ostriches compared to broods in EA than in WA, indicating a significantly lower reproductive success in EAItem Do Ostriches Struthio Camelus Reject Parasitic Eggs by Making use of Colour as a Cue?(Taylor & Francis, 2010-11) Magige, Flora J.; Stokke, Bård G.; Røskaft, EivinThe Ostrich communal breeding system involves several females laying in a single nest. Only the ‘major’ female and the territorial male, however, provide parental care from incubation to fledging of chicks. Eggs are turned and displaced frequently upon the onset of incubation, and the major female evicts excess eggs out of the nest when the number of eggs is above a specific threshold level. A previous study indicated that the major female ostrich recognises her own eggs and selectively evicts eggs of minor females based on size, shape and shell texture. Our aim was to investigate if accepted and ejected eggs differ in colour characteristics. We quantified colour by measuring egg reflectance spectra, which were subsequently analysed using a visual model approach. Within clutches, there were no significant differences in colour between accepted and ejected eggs. These results suggest that female ostriches do not discriminate against foreign eggs based on deviations in colour.Item Does illegal hunting affect ensity and behaviour of African grassland birds? A case study on ostrich (Struthio camelus)(Springer, 2009-04) Magige, Flora J.; Holmern, Tomas; Stokke, Sigbjørn; Mlingwa, Charles; Røskaft, EivinWidespread bushmeat hunting represents one of the major threats to manymammals and birds in Africa. We studied the influence of illegal bushmeat hunting onlarge grassland birds in the Serengeti National Park (SNP) and adjoining protected areas,by using the ostrich (Struthio camelus) as a case study. First, we documented illegalhunting of both small and large birds by using a questionnaire in the villages on the westernand eastern side of the SNP. Second, we studied the effect of illegal hunting on density bydriving 4,659 km of transects inside SNP and on the adjacent protected areas, where thedata were analysed by DISTANCE sampling. Last, we used flight initiation distance (FID,i.e. the distance between an approaching predator (human) and prey when flight is started),to assess possible impacts on behaviour from illegal hunting. We found that people fromthe western side of the SNP admitted to hunting both small and large grassland birds, andcollect ostrich feathers and eggs. Although the Maasai also hunted small birds, only ostrichfeathers and eggs of the large grassland birds were used. Surprisingly, we found no sig-nificant differences in densities between the SNP and adjoining partially protected areas,but ostriches had longer FID to an approaching human outside the SNP. Currently illegalhunting does not appear to affect the ostrich population, but given the extensive use ofbirds for consumption more awareness educational programs accompanied by provision ofagricultural incentives within the protectItem Human Rights and Conservation of Biodiversity Considerations Associated with Roads in The Serengeti: Response to Hopcraft Et Al.: Response to Hopcraft et al.(2015-02) Fyumagwa, Robert D.; Hassan, Shombe N.; Kideghesho, Jafari; Kohi, Edward M.; Magige, Flora J.; Mfunda, Iddi M.; Mwakatobe, A.; Ntalwila, Janemary; Nyahongo, Julius W.; Runyoro, V.; Røskaft, EivinWe are pleased that Hopcraft et al. (2015) responded to our article (Fyumagwa et al. 2013) “Roads as a Threat to the Serengeti Ecosystem.” Many of the authors of this response are senior scientists and conservationists who have worked in the Serengeti ecosystem for decades and have made substantial contributions to ecology and conservation. We therefore take their criticisms seriously. The Serengeti ecosystem contains 2 world heritage sites; thus, international input into developing the region in a sustainable way is welcome. We believe, as do others (e.g., Kareiva 2014), that conservation efforts should consider the livelihoods of people inhabiting an area, independent of the size and density of the human population. Addressing the needs of human communities is consistent with the Convention on Biological Diversity (1992) and the 5th World Parks Congress (2003), which link conservation with human development and poverty reduction (Christ et al. 2003; Eagles 2014). In Fyumagwa et al. (2013), our primary focus is sustainable conservation and human development in the Serengeti ecosystem. We also consider the cost of road construction and the indirect consequences likely to have the greatest effects on nature. In contrast, Hopcraft et al. focus on how to connect the eastern and western towns in northern Tanzania. We believe a holistic view of the situation is needed and invite all parties to collaborate §§Address correspondence to E. Røskaft, email roskaft@bio.ntnu.nItem Responses of the Serengeti Avifauna to Long-Term Change in the Environment(Taylor & Francis, 2014-05) Sinclair, Anthony R. E.; Nkwabi, Ally; Mduma, Simon A. R.; Magige, Flora J.In this paper we examine how climate change interacts with other disturbances to alter the functioning of a tropical ecosystem, the Serengeti in Tanzania. Tropical Africa has increasing temperatures and changes in rainfall. Long-term data have shown how the avifauna responds to the interaction of environmental change with other disturbances: (1) habitat modification through agriculture by limiting endemic species and top trophic levels. Rare species are lost so this is a problem for conservation. Top trophic levels are lost and the lack of predators then releases pests. This is a problem for natural resource management. (2) Disease and hunting cause slow change in the species complex. This can alter community dynamics depending on which species enter or leave. (3) Habitat fragmentation or decay can cause slow change. When this reaches a threshold there may be rapid change in the species composition causing multiple states. One lesson is that present-day ecosystem states and trends can only be understood in the context of past historical events. Another is that all systems change so this requires a new approach to conservation. Within protected areas, new boundaries or new areas will be required. Outside rewilding is required to support more biodiversity.Item Roads as a Threat to the Serengeti Ecosystem(Wiley, 2015-03-26) Fyumagwa, Robert D.; Gereta, E.; Hassan, Shombe N.; Kideghesho, Jafari; Kohi, Edward M.; Keyyu, Julius; Mwakatobe, A.; Ntalwila, Janemary; Nyahongo, Julius W.; Runyoro, V.; Røskaft, Eivin; Magige, Flora J.; Mfunda, Iddi M.In an opinion letter to Nature (September 2010), Dobsonet al. (2010) oppose the planned road through north-ern Tanzania that crosses Serengeti National Park (SNP)(Fig. 1). They contend that the road will jeopardize theSerengeti ecosystem by interrupting the wildebeest (Con-nochaetes taurinus) migratory corridor. This opinion issupported by other scientists using mathematical models(Holdo et al. 2011). However, all arguments presentedagainst the project have been questioned (Homewoodet al. 2010). As has often been the case in the conserva-tion of African natural resources, some scientists presentviews that do not account for other key components ofconservation: economic growth, reduction of poverty,improvement of quality of life, and social well-being. Asscientists working in Serengeti, we believe that the pub-lished reports about the Serengeti road mislead the worldabout its potential effects on the ecosystemItem Rodent Species Diversity in Relation to Altitudinal Gradient in Northern Serengeti, Tanzania(Wiley, 2014-11) Magige, Flora J.Rodents are among the successful small mammals in the world. In species richness, rodents outnumber other mammalian orders owing partly to their capability to exploit many different habitats. Their diversities have been influenced by many factors including the altitude. This study assessed rodent diversity across the two altitudinal zones, that is, lowland western zone and highland eastern zone, in the Serengeti ecosystem, Tanzania. Capture-Mark-Recapture studies were undertaken in November 2009 and April 2010 using live traps in the ecosystem to compare variations in species diversity of rodents in the two zones of the ecosystem. Eight (8) rodent species were recorded in each zone area. However, species richness was higher in crop land and woodland areas than in grasslands in each zone. The two zones comprised of different species diversities for which Rényi Diversity profiles indicated the higher diversity in the eastern zone than the western zone although the difference was not significant (P > 0.05). Differences between the eastern and western zones could be attributed to the altitudinal gradient whereby the east was at a higher elevation than the west. Maintenance and management of wildlife corridors will assist migration of rodents between the two zones and enhance continuous gene flow.Item The White Colour of The Ostrich (Struthio Camelus) Egg is a Trade-off Between Predation and Overheating(Springer, 2008-07) Magige, Flora J.; Moe, Børge; Røskaft, EivinMost ground nesters lay pigmented eggs, and egg pigmentation generally matches the environment. Pigmentation of eggs has evolved as a protective device against predation, but dark-pigmented eggs can be susceptible to overheating when exposed to solar radiation. The Ostrich (Struthio camelus) lays white eggs that are unattended for the first few weeks before incubation, and are quite visible to predators. To evaluate the effect of colour on the surface and core temperatures, we painted some Ostrich eggs dark brown or white, and left some unpainted (control), and exposed all of them directly to the sun during the day. The surface and core temperatures of brown eggs were significantly higher than those of the white-painted and control eggs. In addition, the core temperature of brown eggs exceeded 37.5°C, which is the temperature at which embryo mortality starts to increase. In a second experiment, we placed eggs (brown-painted and control) in various types of vegetation to study their visibility to an observer walking towards them. The white eggs were discovered from a significantly longer distance than the brown eggs, indicating that the predation risk may be much higher for white eggs. The results thus suggest that white eggs minimise overheating and allow the Ostrich to leave its eggs unattended before incubation starts, but they are more susceptible to predation.