In Africa, information on time required for plants to develop from seed to mean size and maximum size is scarce. There is also a lack of information regarding accurate relationships between stem diameter, height and c...In Africa, information on time required for plants to develop from seed to mean size and maximum size is scarce. There is also a lack of information regarding accurate relationships between stem diameter, height and canopy dimensions. This type of information is however becoming a real necessity to allow the accurate measurement of carbon stocks and carbon stocks change to qualify for the UNFCCC’s REDD+ mechanism. We evaluated these parameters for 22 Sand Forest and woodland tree species of South Africa’s Maputaland. Results indicated that it takes approximately 66 and 35 years for current dynamics of Sand Forests and woodlands to occur respectively. Based on diameter and growth rates, larger trees of the forests can be older than 600 years, while large woodland trees can reach ages of 900 years. Our evaluation of linear relationships between stem diameter, height and canopy dimensions showed extremely robust results allowing the use of stem diameter to calculate height and canopy dimensions. The results are of interest for carbon related investigations and reconstructing stands dynamics.展开更多
Human-carnivore conflicts represent the most common negative form of interactions between humans and wildlife. Most carnivores involved in such conflicts are: lion, hyena, leopard and cheetah. Three strategies are nor...Human-carnivore conflicts represent the most common negative form of interactions between humans and wildlife. Most carnivores involved in such conflicts are: lion, hyena, leopard and cheetah. Three strategies are normally used in Kenya to mitigate such conflicts;consolation for lost livestock and human life to increase tolerance to them, use of predator proof homesteads especially among pastoralists, use flicking lights at night to discourage approach of carnivores near homesteads, and awareness creation among communities on the ecological role of carnivores. This study examined human-carnivore interactions in privately owned conservancies near Amboseli National Park, Kenya. The conservancies were found to have almost similar human and livestock demography. However, homesteads in Elerai had more fence broken parts and relatively higher levels of livestock predation by lion and hyena. The higher the number of each livestock type was, the higher the specific predation to that livestock type was, implying density dependent effects of predation by carnivores on livestock. It seemed that the fence structure and level of maintenance (including carnivore strategies on specializing on specific livestock size and age consistent with optimizing their foraging strategies) influenced predation incidences. However, the presence of adult males and Maasai warriors (morans) in bomas did not seem to be related with the number of livestock killed by carnivores, implying that they didn’t add vigilance as an additional strategy to prevent livestock depredation. It is recommended that attention be paid on maintenance of homestead and livestock fences as well as vigilance to deter predation. We further recommend strategies to prevent livestock predation such as, installation of chain link predator proof fences or carnivore lighting deterrents at night because woody plants fences are ineffective and deteriorate easily with time, and also lead to depletion of plant resources critical to households.展开更多
Knowledge of carnivore diets is essential to understand how carnivore populations respond demographically to variations in prey abundance. Analysis of stable isotopes is a useful complement to traditional methods of a...Knowledge of carnivore diets is essential to understand how carnivore populations respond demographically to variations in prey abundance. Analysis of stable isotopes is a useful complement to traditional methods of analyzing carnivore diets. We used data on δ^13C and δ^15N in wolverine tissues to investigate patterns of seasonal and annual diet variation in a wolverine Gulo gulo population in the western Brooks Range, Alaska, USA. The stable isotope ratios in wolverine tissues generally reflected that of terrestrial carnivores, corroborating previous diet studies on wolverines. We also found variation in δ^13C and δ^15N both between muscle samples collected over several years and between tissues with different assimilation rates, even after correcting for isotopic fractionation. This suggests both annual and seasonal diet variation. Our results indicate that data on δ^13C and δ^15N holds promise for qualitative assessments of wolverine diet changes over time. Such temporal variation may be important indicators of ecological responses to environmental perturbations, and we suggest that more refined studies of stable isotopes may be an important tool when studying temporal change in diets of wolverines and similar carnivores [ Current Zoology 55 (3): 188- 192, 2009].展开更多
Understanding of animal spatial behavior is essential for informed management decisions.In southern Africa,reintroduction of lions(Panthera leo)to small reserves(<1000 km2)has increased since the early 2000s,howeve...Understanding of animal spatial behavior is essential for informed management decisions.In southern Africa,reintroduction of lions(Panthera leo)to small reserves(<1000 km2)has increased since the early 2000s,however studies on their ranging behavior in these enclosed systems remain lacking.We applied Time Local Convex Hull(T-LoCoH)methods to study the home range establishment and utilization of 11 lions reintroduced to Dinokeng Game Reserve,South Africa,during 2011 through 2014.Lions established home ranges close to their release sites and during the following 3 years their home range sizes continued to increase,but in each individual case the size remained smaller than half of the reserve area(<70 km2).Space use strategies differed between the core and the entire home range,with higher frequency of visits found in core areas.Exceptionally high rates(>60 separate visits)around the largest dam and along rivers suggest the importance of water and its surrounding vegetation in the lions’space utilization pattern.The home range size did not differ with season or sex of the individuals,whereas shifts in locations of home ranges revealed differences in the response of the 2 sexes to territorial conflicts and management interventions.Our study shows a dynamic home range utilization pattern and highlights the importance of both fine-scale space use patterns(frequency and duration of visits)and broadscale home range changes in understanding the ranging behavior of reintroduced animals.展开更多
文摘In Africa, information on time required for plants to develop from seed to mean size and maximum size is scarce. There is also a lack of information regarding accurate relationships between stem diameter, height and canopy dimensions. This type of information is however becoming a real necessity to allow the accurate measurement of carbon stocks and carbon stocks change to qualify for the UNFCCC’s REDD+ mechanism. We evaluated these parameters for 22 Sand Forest and woodland tree species of South Africa’s Maputaland. Results indicated that it takes approximately 66 and 35 years for current dynamics of Sand Forests and woodlands to occur respectively. Based on diameter and growth rates, larger trees of the forests can be older than 600 years, while large woodland trees can reach ages of 900 years. Our evaluation of linear relationships between stem diameter, height and canopy dimensions showed extremely robust results allowing the use of stem diameter to calculate height and canopy dimensions. The results are of interest for carbon related investigations and reconstructing stands dynamics.
文摘Human-carnivore conflicts represent the most common negative form of interactions between humans and wildlife. Most carnivores involved in such conflicts are: lion, hyena, leopard and cheetah. Three strategies are normally used in Kenya to mitigate such conflicts;consolation for lost livestock and human life to increase tolerance to them, use of predator proof homesteads especially among pastoralists, use flicking lights at night to discourage approach of carnivores near homesteads, and awareness creation among communities on the ecological role of carnivores. This study examined human-carnivore interactions in privately owned conservancies near Amboseli National Park, Kenya. The conservancies were found to have almost similar human and livestock demography. However, homesteads in Elerai had more fence broken parts and relatively higher levels of livestock predation by lion and hyena. The higher the number of each livestock type was, the higher the specific predation to that livestock type was, implying density dependent effects of predation by carnivores on livestock. It seemed that the fence structure and level of maintenance (including carnivore strategies on specializing on specific livestock size and age consistent with optimizing their foraging strategies) influenced predation incidences. However, the presence of adult males and Maasai warriors (morans) in bomas did not seem to be related with the number of livestock killed by carnivores, implying that they didn’t add vigilance as an additional strategy to prevent livestock depredation. It is recommended that attention be paid on maintenance of homestead and livestock fences as well as vigilance to deter predation. We further recommend strategies to prevent livestock predation such as, installation of chain link predator proof fences or carnivore lighting deterrents at night because woody plants fences are ineffective and deteriorate easily with time, and also lead to depletion of plant resources critical to households.
基金support fromthe U.S. National Park Service,the Royal Swedish Academy of Sciences and Siléns FoundationHunters in the Kotzebue area kindly provided us with harvest materialon wolverines,caribou and moose+1 种基金Dan Stevenson and the local staff at the U.S.National Park Service office in Kotzebue for logistical supportto Gene Peltola for help during aninitial stage of the Noatak wolverine project
文摘Knowledge of carnivore diets is essential to understand how carnivore populations respond demographically to variations in prey abundance. Analysis of stable isotopes is a useful complement to traditional methods of analyzing carnivore diets. We used data on δ^13C and δ^15N in wolverine tissues to investigate patterns of seasonal and annual diet variation in a wolverine Gulo gulo population in the western Brooks Range, Alaska, USA. The stable isotope ratios in wolverine tissues generally reflected that of terrestrial carnivores, corroborating previous diet studies on wolverines. We also found variation in δ^13C and δ^15N both between muscle samples collected over several years and between tissues with different assimilation rates, even after correcting for isotopic fractionation. This suggests both annual and seasonal diet variation. Our results indicate that data on δ^13C and δ^15N holds promise for qualitative assessments of wolverine diet changes over time. Such temporal variation may be important indicators of ecological responses to environmental perturbations, and we suggest that more refined studies of stable isotopes may be an important tool when studying temporal change in diets of wolverines and similar carnivores [ Current Zoology 55 (3): 188- 192, 2009].
文摘Understanding of animal spatial behavior is essential for informed management decisions.In southern Africa,reintroduction of lions(Panthera leo)to small reserves(<1000 km2)has increased since the early 2000s,however studies on their ranging behavior in these enclosed systems remain lacking.We applied Time Local Convex Hull(T-LoCoH)methods to study the home range establishment and utilization of 11 lions reintroduced to Dinokeng Game Reserve,South Africa,during 2011 through 2014.Lions established home ranges close to their release sites and during the following 3 years their home range sizes continued to increase,but in each individual case the size remained smaller than half of the reserve area(<70 km2).Space use strategies differed between the core and the entire home range,with higher frequency of visits found in core areas.Exceptionally high rates(>60 separate visits)around the largest dam and along rivers suggest the importance of water and its surrounding vegetation in the lions’space utilization pattern.The home range size did not differ with season or sex of the individuals,whereas shifts in locations of home ranges revealed differences in the response of the 2 sexes to territorial conflicts and management interventions.Our study shows a dynamic home range utilization pattern and highlights the importance of both fine-scale space use patterns(frequency and duration of visits)and broadscale home range changes in understanding the ranging behavior of reintroduced animals.