Law enforcement remains to be the main strategy used to combat poaching and account for high budget share in protected area management. Studies on efficiency of wildlife law enforcement in the protected areas are limi...Law enforcement remains to be the main strategy used to combat poaching and account for high budget share in protected area management. Studies on efficiency of wildlife law enforcement in the protected areas are limited. This study analyzed economic efficiency of wildlife law enforcement in terms of resource used and output generated using three different protected areas (PAs) of Serengeti ecosystem namely Serengeti National Park (SENAPA), Ikorongo/Grumeti Game Reserves (IGGR) and Ikona Wildlife Management Area (IWMA). Three years (2010-2012) monthly data on wildlife law enforcement inputs and outputs were collected from respective PAs authorities and supplemented with key informant interviews and secondary data. Questionnaire surveys were conducted to wildlife law enforcement staff. Shadow prices for non-marketed inputs were estimated, and market prices for marketed inputs. Data Envelopment Analysis (DEA) was used to estimate economic efficiency using Variable Return to Scale (VRS) and Constant Return to Scale (CCR) assumptions. Results revealed that wildlife law enforcement in all PAs was economically inefficient, with less inefficiency observed in IWMA. The less inefficiency in IWMA is likely attributed to existing sense of ownership and responsibility created through community-based conservation which resulted in to decrease in law enforcement costs. A slacks evaluation revealed a potential to reduce fuel consumption, number of patrol vehicles, ration and prosecution efforts at different magnitudes between studied protected areas. There is equal potential to recruit more rangers while maintaining the resting time. These finding forms the bases for monitoring and evaluation with respect to resource usage to enhance efficiency. It is further recommended to enhance community participation in conservation in SENAPA and IGGR to lower law enforcement costs. Collaboration between protected area, police and judiciary is fundamental to enhance enforcement efficiency. Despite old dataset, these findings are relevant s展开更多
We develop a two-species prey-predator model in which prey is wildebeest and predator is lion. The threats to wildebeest are poaching and drought while to lion are retaliatory killing and drought. The system is found ...We develop a two-species prey-predator model in which prey is wildebeest and predator is lion. The threats to wildebeest are poaching and drought while to lion are retaliatory killing and drought. The system is found in the Serengeti ecosystem. Optimal control theory is applied to investigate optimal strategies for controlling the threats in the system where anti-poaching patrols are used for poaching, construction of strong bomas for retaliatory killing and construction of dams for drought control. The possible impact of using a combination of the three controls either one at a time or two at a time on the threats facing the system is also examined. We observe that the best result is achieved by using all controls at the same time, where a combined approach in tackling threats to yield optimal results is a good approach in the management of wildlife populations.展开更多
Short-term, i.e. 4-9 weeks aboveground net primary production (ANPP) temporal patterns during the first post-fire year in western Seren-geti National Park, and potential differences in the factors limiting ANPP betwee...Short-term, i.e. 4-9 weeks aboveground net primary production (ANPP) temporal patterns during the first post-fire year in western Seren-geti National Park, and potential differences in the factors limiting ANPP between burnt and non burnt grasslands were examined and es-tablished. Fire stimulated growth at early post-fire stages, even during the dry season, July-October and led to larger increments in green phytomass compared to the non burnt grassland at the onset of short rains, Octo-ber-December. Further, ANPP in burnt plots correlated well with the ratio leaf/total standing phytomass suggesting that the accumulation of standing dead material can be a limiting factor to ANPP in burnt grass-lands. However, ANPP in burnt plots was unrelated to rainfall contrary to earlier arguments, but reached peak earlier and declined early in the rain season, perhaps due to the interactive effects of fire and grazing in the area. In non burnt plots, the temporal change in ANPP was more related to rainfall availability, at least until mid-growing season. Also, the phytomass structure differed between burnt and non burnt grasslands, and together with litter did not recover to non burnt levels within the first post-fire year. The study has demonstrated that the desire of the fire man-agement program in Serengeti National Park, which is to supply green forage to both migra-tory and resident populations during dry season is being fulfilled.展开更多
Interaction between prey and predator species is a complex and non-linear process. Understanding various phenomena in the dynamics of prey-predator systems is vital to both mathematical ecology and conservation biolog...Interaction between prey and predator species is a complex and non-linear process. Understanding various phenomena in the dynamics of prey-predator systems is vital to both mathematical ecology and conservation biology. Mathematical models on prey-predator systems have been the hot sport providing important information regarding the interactions of prey and predator species in various ecosystems. In this paper, a review of the available mathematical models on prey-predator systems was done. Our aim was to assess their structure, behaviour, available control strategies, population involved and their ability in predicting the future behaviour of the ecosystems. We observed diversities in the reviewed mathematical models, some model incorporated factors such as drought, harvesting and prey refuge as the factors that affect ecosystems, some ignored the contribution of environmental variations while others considered the variable carrying capacity. Most of the models reviewed have not considered the contribution of diseases and seasonal weather variation in the dynamics of prey predator systems. Some of the reviewed models do not match the real situation in most modelled ecosystems. Thus, to avoid unreliable results, this review reveals the need to incorporate seasonal weather variations and diseases in the dynamics of prey predator systems of Serengeti ecosystem.展开更多
Serengeti is the largest ecosystem in Tanzania endowed with high level of biodiversity in protected and unprotected areas. Serengeti National Park is the only protected area in a matrix of unprotected areas characteri...Serengeti is the largest ecosystem in Tanzania endowed with high level of biodiversity in protected and unprotected areas. Serengeti National Park is the only protected area in a matrix of unprotected areas characterized with a wide range of human activities which threaten biodiversity conservation. It was assessed plant species composition, diversity, distribution and vegetation structure in both the protected and unprotected areas of the ecosystem. Two transects with twenty plots each were established in each vegetation type in which data was collected. A significantly higher species composition (262) and diversity (2.39 ± 0.03) was observed in unprotected areas than in the protected area (163 and 2.06 ± 0.04 respectively). The DCA ordination of the species data from the two management regimes formed four clusters based on similarity in plant species composition, where three clusters were from unprotected areas and one from protected area. The variations in plant species composition ranged from 35.69% to 65.92% for the first four DCA axes. There was no significant difference in stem density between protected and unprotected areas of the ecosystem. Although high density of trees at 10 - 14 cm DBH sizes was observed in both sides of the conservation management regimes, individuals with DBH above 65 cm existed in the protected area but were absent in unprotected areas. It can be concluded that the decrease of plant species diversity and density in unprotected area is because of habitat degradation associated with exploitation pressure, livestock grazing and other forms of disturbance related with anthropogenic activities. Because of high demand for plant resources, the local community needs to establish woodlots to cater for wood resource needs outside the protected areas of Serengeti. Also, pastoralists need to diversify livestock keeping systems compatible with limited grazing land in unprotected area of the Serengeti ecosystem.展开更多
Aims Invasive species alter the composition and function of communities,threatening the conservation of important ecosystems worldwide.In savanna ecosystems,fire plays a key role by modifying biogeochemical cycles and...Aims Invasive species alter the composition and function of communities,threatening the conservation of important ecosystems worldwide.In savanna ecosystems,fire plays a key role by modifying biogeochemical cycles and shaping the composition and structure of vegetation communities.Although many studies have examined the long-term effects of fire frequency on grassland communities,few studies have examined the relationship between fire regime and woody species invasions.Methods The Serengeti ecosystem is an ecologically and economically valuable natural resource in East Africa whose conservation is currently threatened by a variety of factors,including invasive species.We determined the abundance of Maerua subcordata,a noxious woody shrub,in three different regions of the Serengeti National Park,Tanzania.We then examined the influence of fire frequency,developed through the use of 7 years of Moderate Resolution Imaging Spectroradiometer(MODIS)imagery,on M.subcordata abundance.Important Findings In all regions,burned transects had significantly greater abundances of M.subcordata compared to unburned transects.Furthermore,the number of times each transect burned from 2000 to 2006 had a significant positive effect on the abundance of M.subcordata and the number of years since a transect last burned had a significant negative relationship with abundance.These results are particularly important as this species provides little forage value and is potentially toxic to wildlife and cattle.Additional studies are needed to determine the ecological consequences of increasing M.subcordata abundance,as the potential expansion of noxious shrubs into protected areas of important conservation status is of serious concern.展开更多
As one of the last remaining naturally grazed ecosystems on Earth,the Serengeti National Park is an ideal location to study the influence of migratory mammals on the structure of microbial communities and the factors ...As one of the last remaining naturally grazed ecosystems on Earth,the Serengeti National Park is an ideal location to study the influence of migratory mammals on the structure of microbial communities and the factors that generate biogeography of soil microbes.Furthermore,volcanic inputs generate environmental gradients that may also structure microbial communities.We studied 16S rRNA amplicons in a 13-year herbivore removal experiment to examine the influence of grazing and environmental gradients on the natural distribution of soil microbes.Removal of mammalian herbivores shifted microbial community structure,with 31 taxa that were significant indicator taxa of the ungrazed treatment and three taxa that were indicators of the grazed treatment.The abundance of many taxa were correlated with soil texture,phosphorus,iron,calcium and rainfall,and the evenness of taxa within samples was also correlated with these variables.Bayesian general linear mixed effects models with single predictors of multiple,highly correlated variables of beta diversity were consistent with a significant,but weak(2%),effect of grazing,and stronger effects of phosphorus(14%).Beta diversity of microbial communities was greater in grazed than in ungrazed plots;suggesting that the impacts of grazing on community assembly of microbes results from deterministic environmental filtering caused by the influence of herbivores on plant communities and soil properties rather than stochastic dispersal via herds of large mammals.These herbivore effects are superimposed on deterministic environmental filtering by natural soil and precipitation gradients across the Serengeti.展开更多
文摘Law enforcement remains to be the main strategy used to combat poaching and account for high budget share in protected area management. Studies on efficiency of wildlife law enforcement in the protected areas are limited. This study analyzed economic efficiency of wildlife law enforcement in terms of resource used and output generated using three different protected areas (PAs) of Serengeti ecosystem namely Serengeti National Park (SENAPA), Ikorongo/Grumeti Game Reserves (IGGR) and Ikona Wildlife Management Area (IWMA). Three years (2010-2012) monthly data on wildlife law enforcement inputs and outputs were collected from respective PAs authorities and supplemented with key informant interviews and secondary data. Questionnaire surveys were conducted to wildlife law enforcement staff. Shadow prices for non-marketed inputs were estimated, and market prices for marketed inputs. Data Envelopment Analysis (DEA) was used to estimate economic efficiency using Variable Return to Scale (VRS) and Constant Return to Scale (CCR) assumptions. Results revealed that wildlife law enforcement in all PAs was economically inefficient, with less inefficiency observed in IWMA. The less inefficiency in IWMA is likely attributed to existing sense of ownership and responsibility created through community-based conservation which resulted in to decrease in law enforcement costs. A slacks evaluation revealed a potential to reduce fuel consumption, number of patrol vehicles, ration and prosecution efforts at different magnitudes between studied protected areas. There is equal potential to recruit more rangers while maintaining the resting time. These finding forms the bases for monitoring and evaluation with respect to resource usage to enhance efficiency. It is further recommended to enhance community participation in conservation in SENAPA and IGGR to lower law enforcement costs. Collaboration between protected area, police and judiciary is fundamental to enhance enforcement efficiency. Despite old dataset, these findings are relevant s
文摘We develop a two-species prey-predator model in which prey is wildebeest and predator is lion. The threats to wildebeest are poaching and drought while to lion are retaliatory killing and drought. The system is found in the Serengeti ecosystem. Optimal control theory is applied to investigate optimal strategies for controlling the threats in the system where anti-poaching patrols are used for poaching, construction of strong bomas for retaliatory killing and construction of dams for drought control. The possible impact of using a combination of the three controls either one at a time or two at a time on the threats facing the system is also examined. We observe that the best result is achieved by using all controls at the same time, where a combined approach in tackling threats to yield optimal results is a good approach in the management of wildlife populations.
文摘Short-term, i.e. 4-9 weeks aboveground net primary production (ANPP) temporal patterns during the first post-fire year in western Seren-geti National Park, and potential differences in the factors limiting ANPP between burnt and non burnt grasslands were examined and es-tablished. Fire stimulated growth at early post-fire stages, even during the dry season, July-October and led to larger increments in green phytomass compared to the non burnt grassland at the onset of short rains, Octo-ber-December. Further, ANPP in burnt plots correlated well with the ratio leaf/total standing phytomass suggesting that the accumulation of standing dead material can be a limiting factor to ANPP in burnt grass-lands. However, ANPP in burnt plots was unrelated to rainfall contrary to earlier arguments, but reached peak earlier and declined early in the rain season, perhaps due to the interactive effects of fire and grazing in the area. In non burnt plots, the temporal change in ANPP was more related to rainfall availability, at least until mid-growing season. Also, the phytomass structure differed between burnt and non burnt grasslands, and together with litter did not recover to non burnt levels within the first post-fire year. The study has demonstrated that the desire of the fire man-agement program in Serengeti National Park, which is to supply green forage to both migra-tory and resident populations during dry season is being fulfilled.
文摘Interaction between prey and predator species is a complex and non-linear process. Understanding various phenomena in the dynamics of prey-predator systems is vital to both mathematical ecology and conservation biology. Mathematical models on prey-predator systems have been the hot sport providing important information regarding the interactions of prey and predator species in various ecosystems. In this paper, a review of the available mathematical models on prey-predator systems was done. Our aim was to assess their structure, behaviour, available control strategies, population involved and their ability in predicting the future behaviour of the ecosystems. We observed diversities in the reviewed mathematical models, some model incorporated factors such as drought, harvesting and prey refuge as the factors that affect ecosystems, some ignored the contribution of environmental variations while others considered the variable carrying capacity. Most of the models reviewed have not considered the contribution of diseases and seasonal weather variation in the dynamics of prey predator systems. Some of the reviewed models do not match the real situation in most modelled ecosystems. Thus, to avoid unreliable results, this review reveals the need to incorporate seasonal weather variations and diseases in the dynamics of prey predator systems of Serengeti ecosystem.
文摘Serengeti is the largest ecosystem in Tanzania endowed with high level of biodiversity in protected and unprotected areas. Serengeti National Park is the only protected area in a matrix of unprotected areas characterized with a wide range of human activities which threaten biodiversity conservation. It was assessed plant species composition, diversity, distribution and vegetation structure in both the protected and unprotected areas of the ecosystem. Two transects with twenty plots each were established in each vegetation type in which data was collected. A significantly higher species composition (262) and diversity (2.39 ± 0.03) was observed in unprotected areas than in the protected area (163 and 2.06 ± 0.04 respectively). The DCA ordination of the species data from the two management regimes formed four clusters based on similarity in plant species composition, where three clusters were from unprotected areas and one from protected area. The variations in plant species composition ranged from 35.69% to 65.92% for the first four DCA axes. There was no significant difference in stem density between protected and unprotected areas of the ecosystem. Although high density of trees at 10 - 14 cm DBH sizes was observed in both sides of the conservation management regimes, individuals with DBH above 65 cm existed in the protected area but were absent in unprotected areas. It can be concluded that the decrease of plant species diversity and density in unprotected area is because of habitat degradation associated with exploitation pressure, livestock grazing and other forms of disturbance related with anthropogenic activities. Because of high demand for plant resources, the local community needs to establish woodlots to cater for wood resource needs outside the protected areas of Serengeti. Also, pastoralists need to diversify livestock keeping systems compatible with limited grazing land in unprotected area of the Serengeti ecosystem.
基金This research was partially funded by the Tufts Institute of the Environment and the Department of Biology at Tufts University.
文摘Aims Invasive species alter the composition and function of communities,threatening the conservation of important ecosystems worldwide.In savanna ecosystems,fire plays a key role by modifying biogeochemical cycles and shaping the composition and structure of vegetation communities.Although many studies have examined the long-term effects of fire frequency on grassland communities,few studies have examined the relationship between fire regime and woody species invasions.Methods The Serengeti ecosystem is an ecologically and economically valuable natural resource in East Africa whose conservation is currently threatened by a variety of factors,including invasive species.We determined the abundance of Maerua subcordata,a noxious woody shrub,in three different regions of the Serengeti National Park,Tanzania.We then examined the influence of fire frequency,developed through the use of 7 years of Moderate Resolution Imaging Spectroradiometer(MODIS)imagery,on M.subcordata abundance.Important Findings In all regions,burned transects had significantly greater abundances of M.subcordata compared to unburned transects.Furthermore,the number of times each transect burned from 2000 to 2006 had a significant positive effect on the abundance of M.subcordata and the number of years since a transect last burned had a significant negative relationship with abundance.These results are particularly important as this species provides little forage value and is potentially toxic to wildlife and cattle.Additional studies are needed to determine the ecological consequences of increasing M.subcordata abundance,as the potential expansion of noxious shrubs into protected areas of important conservation status is of serious concern.
文摘As one of the last remaining naturally grazed ecosystems on Earth,the Serengeti National Park is an ideal location to study the influence of migratory mammals on the structure of microbial communities and the factors that generate biogeography of soil microbes.Furthermore,volcanic inputs generate environmental gradients that may also structure microbial communities.We studied 16S rRNA amplicons in a 13-year herbivore removal experiment to examine the influence of grazing and environmental gradients on the natural distribution of soil microbes.Removal of mammalian herbivores shifted microbial community structure,with 31 taxa that were significant indicator taxa of the ungrazed treatment and three taxa that were indicators of the grazed treatment.The abundance of many taxa were correlated with soil texture,phosphorus,iron,calcium and rainfall,and the evenness of taxa within samples was also correlated with these variables.Bayesian general linear mixed effects models with single predictors of multiple,highly correlated variables of beta diversity were consistent with a significant,but weak(2%),effect of grazing,and stronger effects of phosphorus(14%).Beta diversity of microbial communities was greater in grazed than in ungrazed plots;suggesting that the impacts of grazing on community assembly of microbes results from deterministic environmental filtering caused by the influence of herbivores on plant communities and soil properties rather than stochastic dispersal via herds of large mammals.These herbivore effects are superimposed on deterministic environmental filtering by natural soil and precipitation gradients across the Serengeti.
