Misreading the African Landscape: Society and Ecology in a Forest-Savanna Mosaic

Misreading the African Landscape: Society and Ecology in. Forest-Savanna Mosaic. J. Fairhead and M. Leach. Cambridge: Cambridge University Press, 1996. 354 pp.     

The Importance of Bushmeat in the Livelihoods of West African Cash-Crop Farmers Living in a Faunally-Depleted Landscape

Bushmeat is an important resource in the livelihoods of many rural communities in sub-Saharan Africa and may be a crucial safety-net for the most vulnerable households, especially during times of economic hardship. However, little is known about the impacts of wildlife depletion on these functions. This study quantifies the role of bushmeat in diversified rural household economies in a wildlife depleted forest-farm landscape in Ghana, assessing its importance overall, as well as differentiated by the relative vulnerability of households. Using repeat socioeconomic questionnaires (N=787) among 63 households over a one-year period, the following hypotheses were tested: (a) vulnerable households harvest more bushmeat; (b) bushmeat contributes a greater proportion of household production in vulnerable households; (c) bushmeat is more important for cash income than consumption in vulnerable households; and (d) bushmeat sales are more important for vulnerable households. The bushmeat harvest value averaged less than US$1.0 per day for 89% of households and comprised less than 7% of household production value. Household wealth and gender of the household head had little effect on the importance of bushmeat. However, bushmeat harvest and sales were highest during the agricultural lean season. Overall, most harvested bushmeat (64%) was consumed, enabling households to spend 30% less on meat/fish purchases. These findings suggest that, despite heavily depleted wildlife and diversified livelihoods, bushmeat continues to have an important role in rural livelihoods by acting as a safety net for income smoothing and reducing household expenditure during times of economic hardship.     

Captive Reptile Mortality Rates in the Home and Implications for the Wildlife Trade

The trade in wildlife and keeping of exotic pets is subject to varying levels of national and international regulation and is a topic often attracting controversy. Reptiles are popular exotic pets and comprise a substantial component of the live animal trade. High mortality of traded animals raises welfare concerns, and also has implications for conservation if collection from the wild is required to meet demand. Mortality of reptiles can occur at any stage of the trade chain from collector to consumer. However, there is limited information on mortality rates of reptiles across trade chains, particularly amongst final consumers in the home. We investigated mortality rates of reptiles amongst consumers using a specialised technique for asking sensitive questions, additive Randomised Response Technique (aRRT), as well as direct questioning (DQ). Overall, 3.6% of snakes, chelonians and lizards died within one year of acquisition. Boas and pythons had the lowest reported mortality rates of 1.9% and chameleons had the highest at 28.2%. More than 97% of snakes, 87% of lizards and 69% of chelonians acquired by respondents over five years were reported to be captive bred and results suggest that mortality rates may be lowest for captive bred individuals. Estimates of mortality from aRRT and DQ did not differ significantly which is in line with our findings that respondents did not find questions about reptile mortality to be sensitive. This research suggests that captive reptile mortality in the home is rather low, and identifies those taxa where further effort could be made to reduce mortality rates.     

Wildlife harvesting guidelines for community-based wildlife management: a southern African perspective

African wildlife populations and their habitats are dwindling outside ofstate-protected areas due to escalating human demands on natural resources,while the effective enforcement of conservation legislation is impracticableacross most of the continent. A particular conservation crisis is looming insouthern Africa, where extensive wildlife areas are rapidly giving way tosubsistence agropastoralism. The concept of community-based wildlife management(CBWM) has been embraced by donor agencies as a hopeful solution in areas whereadequate wildlife resources persist and agricultural potential is marginal. Theconservation value of CBWM depends, however, on communities having specificinformation to evaluate the sustainable benefits of wildlife in comparison withalternative landuse options. Furthermore, simple but scientifically soundmonitoring procedures are required to ensure that the offtake from wildlifepopulations is kept within sustainable limits. This paper draws together keyecological issues of relevance to CBWM in southern African savannas andidentifies topics requiring further attention from ecologists. The aim is toassist conservation and development agencies in providing prompt and appropriatetechnical support to communities in areas where opportunities for CBWM stillexist but could soon be foreclosed.     

Road Development and the Geography of Hunting by an Amazonian Indigenous Group: Consequences for Wildlife Conservation

Protected areas are essential for conservation of wildlife populations. However, in the tropics there are two important factors that may interact to threaten this objective: 1) road development associated with large-scale resource extraction near or within protected areas; and 2) historical occupancy by traditional or indigenous groups that depend on wildlife for their survival. To manage wildlife populations in the tropics, it is critical to understand the effects of roads on the spatial extent of hunting and how wildlife is used. A geographical analysis can help us answer questions such as: How do roads affect spatial extent of hunting? How does market vicinity relate to local consumption and trade of bushmeat? How does vicinity to markets influence choice of game? A geographical analysis also can help evaluate the consequences of increased accessibility in landscapes that function as source-sink systems. We applied spatial analyses to evaluate the effects of increased landscape and market accessibility by road development on spatial extent of harvested areas and wildlife use by indigenous hunters. Our study was conducted in Yasuní Biosphere Reserve, Ecuador, which is impacted by road development for oil extraction, and inhabited by the Waorani indigenous group. Hunting activities were self-reported for 12–14 months and each kill was georeferenced. Presence of roads was associated with a two-fold increase of the extraction area. Rates of bushmeat extraction and trade were higher closer to markets than further away. Hunters located closer to markets concentrated their effort on large-bodied species. Our results clearly demonstrate that placing roads within protected areas can seriously reduce their capacity to sustain wildlife populations and potentially threaten livelihoods of indigenous groups who depend on these resources for their survival. Our results critically inform current policy debates regarding resource extraction and road building near or within protected areas.     

Garden Game: Shifting Cultivation,Indigenous Hunting and Wildlife Ecology in Western Panama

Participatory research documented the hunting yields of 59 households in five neighboring indigenous villages in western Panama. These households captured 2,580 kg of game over 8 months, with 47% of the harvest coming from agricultural areas. The quantity of game captured in anthropogenic habitats is influenced by the hunting strategies employed. Only 25% of game captured during hunting trips was captured in agricultural areas, as opposed to 93% while “awaiting” and 65% using traps. Reliance on different strategies is in turn dependent on age, gender, and access to firearms. I argue that garden hunting is not a response to game depletion, but rather a productive activity that is complementary to broader cultural and economic patterns, and that simultaneously protects crops from animal predation. The creation of heterogeneous habitat mosaics through shifting cultivation has played a key role in the relationship between people and wildlife in the humid neotropics, leading to adjustments in both animal foraging patterns and indigenous hunting practices.     

Rapid Assessment of Distribution of Wildlife and Human Activities for Prioritizing Conservation Actions in a Patagonian Landscape

Large landscapes encompassing reserves and areas with other human uses are necessary for conservation of many species. Generating information for conservation planning over such landscapes may be expensive and time-consuming, though resources for conservation are generally limited and conservation is often urgent. We developed a sign-based occupancy survey to help prioritize conservation interventions by simultaneously assessing the distribution of 3 species, the lesser rhea, guanaco, and mara, and their association with human activities in a 20,000-km² landscape in the northern Patagonian steppe. We used a single-season occupancy model with spatial rather than temporal replication of surveys in order to reduce costs of multiple visits to sites. We used covariates related to detectability, environmental factors, and different human activities to identify the most plausible models of occupancy, and calculated importance weights of covariates from these models to evaluate relative impacts of human activities on each species. Abundance of goats had the strongest negative association with lesser rheas and guanacos, and road density with maras. With six months of fieldwork, our results provided initial hypotheses for adaptive conservation interventions for each species. Addressing high livestock densities for rheas and guanacos, poaching by urban hunters for all three species, and hunting by rural people for rheas are priorities for conservation in this landscape. Our methodology provided new insights into the responses of these species, although low detection probabilities for maras indicate that the sampling scheme should be altered for future monitoring of this species. This method may be adapted for any large landscape where a rapid, objective means for prioritizing conservation actions on multiple species is needed and data are scarce.     

The Ethnography of Landscape: GIS and Remote Sensing in the Study of Forest Change in West African Guinea Savanna

In this paper we explore the application of Amazonian forest change models to the Guinea savanna environment of western Africa. In particular, we examine recent research documenting the growth of peri-village forest islands in the area of Kissidougou, Guinea, which purports to challenge the pervasive view of Guinea savanna deforestation brought about by human activity. As a more systematic approach to the analysis of human/environmental interactions, we propose an "ethnography of landscape," in which the findings of detailed, local ethnographic and ecological case studies are combined with remotely sensed information on what the wider region looks like as it changes over time. In pursuing this research, we employ aerial photography and Geographic Information Systems (GIS) techniques to examine our study area of Kilimi in northwestern Sierra Leone. We show that a Kissidougou-type model of peri-village forest island growth is not applicable to this region, where other environmental change processes are underway. In future work, we propose to employ Landsat satellite image archives to examine, monitor, and compare processes of ecological change throughout the Guinea savanna. [deforestation, ecological anthropology, remote sensing, Sierra Leone, West Africa]     

Seasonal variations in the density of a small West African lake

The seasonal variation in the vertical density profile of Lake Asejire waters was investigated from February 1974 to February 1976.The range of density was of the magnitude of 2.0 mg/cc, at the temperatures of Lake Asejire (21°C–32°C). Water densities were generally lower in the dry season when aquatic temperatures were high and generally higher in the rainy season when aquatic temperatures were low.During the dry season, the pycnocline was observed at 3m–7m in 1974 and 6 m–9 m in 1975. During periods of density stratification, the water body was clearly layered.Seasonal longitudinal differences in water density were such that during the floods of 1975 the inflow station waters had a higher density than the dam-site waters which however had a concomitantly higher conductivity. This suggests the insignificance of conductivity in water density changes in a lake with rather low conductivity values.     

Mycoflora and aflatoxins in a West African corn-groundnut based convenience food

A total of 14 fungal species, mostly toxigenic, were isolated from 50 samples of donkwa snack obtained from 16 producers. All of the isolates recorded substantial growth, though at varying rates, on the 2% snack agar provided. They also induced a reduction in the oil and an increase in free fatty acids of the substrate suggesting their participatory roles in deterioration. Most of the snack samples analysed contained initial amounts of aflatoxins above the safe permissible level (30 ppb). The initial toxin levels increased substantially with storage time under 79.5, 89.5 and 100% ambient relative humidities but increased only slightly when samples were kept at 71% relative humidity. Almost constant toxin levels were recorded throughout the study period under 51% relative humidity. Accumulation of aflatoxin B₁ in samples was most enhanced at 89.5% relative humidity. Comparatively, greater amounts of aflatoxin B₁ accumulated under all conditions than the amounts recorded for aflatoxin G₁.     

Woody Debris Volume Depletion Through Decay: Implications for Biomass and Carbon Accounting

Woody debris decay rates have recently received much attention because of the need to quantify temporal changes in forest carbon stocks. Published decay rates, available for many species, are commonly used to characterize deadwood biomass and carbon depletion. However, decay rates are often derived from reductions in wood density through time, which when used to model biomass and carbon depletion are known to underestimate rate loss because they fail to account for volume reduction (changes in log shape) as decay progresses. We present a method for estimating changes in log volume through time and illustrate the method using a chronosequence approach. The method is based on the observation, confirmed herein, that decaying logs have a collapse ratio (cross-sectional height/width) that can serve as a surrogate for the volume remaining. Combining the resulting volume loss with concurrent changes in wood density from the same logs then allowed us to quantify biomass and carbon depletion for three study species. Results show that volume, density, and biomass follow distinct depletion curves during decomposition. Volume showed an initial lag period (log dimensions remained unchanged), even while wood density was being reduced. However, once volume depletion began, biomass loss (the product of density and volume depletion) occurred much more rapidly than density alone. At the temporal limit of our data, the proportion of the biomass remaining was roughly half that of the density remaining. Accounting for log volume depletion, as demonstrated in this study, provides a comprehensive characterization of deadwood decomposition, thereby improving biomass-loss and carbon-accounting models.     

Depletion of the thioredoxin homologue tryparedoxin impairs antioxidative defence in African trypanosomes

In trypanosomes, the thioredoxin-type protein TXN (tryparedoxin) is a multi-purpose oxidoreductase that is involved in the detoxification of hydroperoxides, the synthesis of DNA precursors and the replication of the kinetoplastid DNA. African trypanosomes possess two isoforms that are localized in the cytosol and in the mitochondrion of the parasites respectively. Here we report on the biological significance of the cTXN (cytosolic TXN) of Trypanosoma brucei for hydroperoxide detoxification. Depending on the growth phase, the concentration of the protein is 3-7-fold higher in the parasite form infecting mammals (50-100 microM) than in the form hosted by the tsetse fly (7-34 microM). Depletion of the mRNA in bloodstream trypanosomes by RNA interference revealed the indispensability of the protein. Proliferation and viability of cultured trypanosomes were impaired when TXN was lowered to 1 muM for more than 48 h. Although the levels of glutathione, glutathionylspermidine and trypanothione were increased 2-3.5-fold, the sensitivity against exogenously generated H2O2 was significantly enhanced. The results prove the essential role of the cTXN and its pivotal function in the parasite defence against oxidative stress.     

A phylogenetic community approach for studying termite communities in a West African savannah

Termites play fundamental roles in tropical ecosystems, and mound-building species in particular are crucial in enhancing species diversity, from plants to mammals. However, it is still unclear which factors govern the occurrence and assembly of termite communities. A phylogenetic community approach and null models of species assembly were used to examine structuring processes associated with termite community assembly in a pristine savannah. Overall, we did not find evidence for a strong influence of interspecific competition or environmental filtering in structuring these communities. However, the presence of a single species, the mound-building termite Macrotermes bellicosus, left a strong signal on structuring and led to clustered communities of more closely related species. Hence, this species changes the assembly rules for a whole community. Our results show the fundamental importance of a single insect species for community processes, suggesting that more attention to insect species is warranted when developing conservation strategies.     

Challenging the Woodfuel Crisis in West African Woodlands

Fear of an upcoming woodfuel crisis caused by increasing woodfuel consumption in Bamako has had great influence on forestry policies aiming to reduce the impacts of urban woodfuel consumption. During the last 20 years, energy gap analyses—the relationship between supply and demand of woodfuels—have been produced by the government of Mali to prove the impacts of woodfuel consumption in Bamako on surrounding woodlands. This study evaluates the methodology and data used to describe this woodfuel crisis through a comparison with regional and historical data. The results of the energy gap analyses are challenged by using different estimates of woody resource availability and woodfuel consumption to create best and worst case scenarios. These show either high surpluses or high deficits with a difference of 2.7 million tons/yr. The woodfuel system of Bamako is highly dynamic and it is very difficult to evaluate its sustainability using a simple methodology such as the energy gap analysis. Trends over the last 20 years show a highly efficient woodfuel system that has adapted to changing circumstances, ensuring a continued affordable woodfuel supply for the urban residents. Better data on the productivity of West African woodlands and urban consumption are needed to avoid misinterpretations of the impacts of woodfuel harvesting on woody resources.     

Maximizing the Wildlife Conservation Value of Road Right-of-Ways in an Agriculturally Dominated Landscape

There has been a growing recognition that the narrow linear strips of uncultivated vegetation that lie between roads and agricultural crops, referred to as roadside right-of-ways or verges, can serve as areas for the conservation of wildlife. The features of right-of-ways that should influence the composition of wildlife communities vary considerably. Our goal was to determine what features of right-of-ways increased the conservation potential of right-of-ways for wildlife in a grassland system dominated by agricultural production. We sampled 100 right-of-ways for birds and 92 right-of-ways for small mammals in McDonough and Warren Counties in west-central Illinois. We found that the sizes of right-of-ways and the amount of traffic on the adjacent roads synergistically worked to influence wildlife communities. On roads with low traffic, avian species richness increased rapidly with increased right-of-way width, while on roads with high traffic, avian richness increased only slightly with increasing right-of-way widths. We found that wider roadside right-of-ways (preferably across the road from equally wide right-of-ways) with thicker and taller vegetation had the greatest conservation value for birds and small mammals. The features that enhanced the conservation value of right-of-ways in our study area were uncommon. Efforts to create or enhance these features for the benefit of wildlife would likely face numerous obstacles. Nonetheless, from a grassland conservation perspective, working with stakeholders to implement specific strategies to enhance these often neglected areas may be an effective complement to purchasing and restoring conservation lands away from roads.     

Establishment and Short-term Productivity of Annual and Perennial Bioenergy Crops Across a Landscape Gradient

Bioenergy crops may help achieve multiple energy, economic, and environmental objectives in the US Midwest, but a portfolio of crops must first be developed and tested in comparison to the current standard, maize (Zea mays L.). The nascent, but long-term and ongoing Landscape Biomass Project in Boone County, Iowa, USA examines five cropping systems including continuous maize, a modified maize–soy [Glycine max (L.) Merr.] rotation, nurse cropped maize–switchgrass (Panicum virgatum L.), double-cropped triticale (Triticosecale?×?Whit.)/sorghum (Sorghum bicolor (L.) Moench), and intercropped triticale–aspen (Crandon [Populus alba?×?Populus grandidentata]) over an elevation gradient. Here, we report perennial establishment and crop productivity across five landscape positions during the first 4 years (2009–2012) of this experiment. Perennials (switchgrass and aspen) established successfully across the gradient with minimal effect of landscape position. Continuous maize had the highest biomass yields both within and over growing seasons, but they declined over time. In comparison, the diversified and perennial systems had lower, but stable or increasing yields over time, despite extreme weather conditions. Landscape position did not consistently influence biomass yield; its effect depended on year and cropping system. Cropping system productivity was generally consistent across the landscape within a given year with greater variability between years. Findings help explain why landscape is often disregarded in Midwestern crop management: it does not seem to substantially drive crop, and thus economic, performance in the short term. Conversely, related Landscape Biomass studies find landscape influences important ecosystem functions (e.g., soil carbon storage) and should be an integral management consideration.     

藏西北地区传统与现代狩猎模式变迁与野生动物保护调查分析

藏西北地区有近两万年的狩猎野生动物历史.人们的狩猎活动对当地野生动物的种群产生了重要影响.通过半结构式访谈、实地考察及文献资料收集等方式,对藏西北地区传统与现代狩猎模式进行了对比分析.结果 显示,两种狩猎模式在目的 、方法、工具等方面均存在较大差异,而且现代狩猎模式对野生动物种群的影响较大.