Rainfall variability and Twareg perceptions of climate impacts in Niger

A survey was conducted among the pastoral Twareg of Niger on their perceptions of rainfall impacts for each year from 1947 through 1988. The herders saw drought as a prolonged process with a multi-year onset that culminated in a single year of extreme crisis and abated gradually. The identified crisis years, 1973 and 1984, corresponded with historical rainfall data that showed each of these to have been the second consecutive year of extreme drought. Single years of drought, which may have served as red-flag signals of impending crisis scenarios, were not identified by the herders. Rainfall measurements from the zone of extensive cultivation, south of the pastoral habitat, did not correlate well with key crisis years or the herders' perceptions. Neither did national-level livestock market statistics. It was concluded that rainfall was a reliable indicator for a drought early warning system for the northern Sahel, provided that the measurements were taken from an ecologically-defined pastoral habitat.This paper was written while the author was a research affiliate at the University of Florida Center for African Studies.     

Botanical Knowledge and its Differentiation by Age,Gender and Ethnicity in Southwestern Niger

Indigenous knowledge is unevenly distributed. Individual knowledge level may be affected by many factors such as gender, age, ethnicity, profession, religious and cultural beliefs, abundance and usefulness of the species. This study documents indigenous knowledge of herbaceous and woody plant species of farmers and herders in southwestern Niger. Specifically, we examine the effects of age, gender, and ethnicity on knowledge of local vegetation. Results from the study showed that on average a higher proportion of woody species was identified by the respondents compared to herbaceous species. Both gender and ethnicity had a significant effect on the identification of herbaceous species but no effect on identification of woody species. Respondents in lower age group (10 to 30 years) identified lower number of species compared to other age classes. There seems to be a curvilinear relationship between age of respondents and number of plant species identified. Results from this study reaffirm the uneven distribution of indigenous knowledge within a given area due to social factors. The main challenge is how to incorporate these social differences in knowledge of native plant species into sustainable management and conservation of community natural resources.

Herders' Perceptions, Practice, and Problems of Night Grazing in the Sahel: Case Studies from Niger

A survey was conducted from February to June of 1997 among livestock herders in two villages of Niger, Kodey and Toukounous, on their perceptions, practice, and problems of night grazing. Cattle and sheep were the species that were taken out for night grazing by the herders. Small herd size and labor constraints were mentioned as the principal reasons for not practicing night grazing. Major benefits of night grazing included good body condition, herd growth, increased milk production, prevention of diseases, and reduction in herd mortality. Insecurity, difficulty in staying awake at night, labor constraints, and damage to crops by animals were given as problems of night grazing. According to the herders, grazing time (duration) during the day and night was shorter in the wet season than in the dry season. In the wet season animals were herded (followed and closely supervised by herders), whereas in the dry season, animals were mostly left to range freely in both villages. In general, children herded the animals during the day, while adults were responsible for night-time herding. Herders' perceptions on night grazing as regards animal production parameters such as weight development, water consumption, fecal output and feeding behavior are consistent with available experimental results. Therefore, future technical research needs to recognize the constraints faced by herders and determine how to overcome them to improve technical and economic efficiency.     

Longitudinal follow‐up of malaria transmission dynamics in two villages in a Sahelian area of Niger during a nationwide insecticide‐treated bednet distribution programme

Malaria transmission was monitored in two villages in the Sahel zone of Niger over 4 years. During this period, a nationwide vector control programme was carried out in which insecticide‐treated bednets were distributed free to mothers of children aged <5 years. Anopheles gambiae and Anopheles arabiensis (Diptera: Culicidae) were found to be the major malaria vectors. The dynamics of An. gambiae s.l. did not vary dramatically over the study period although the proportion of female mosquitoes found resting indoors decreased in both villages and, in one village, the parity rate and sporozoite index were significantly reduced after bednet distribution. By contrast with An. gambiae, the dynamics of Anopheles funestus altered greatly after the bednet distribution period, when adult density, endophagous rate and sporozoite rates decreased dramatically. Our observations highlight the importance of quantifying and monitoring the dynamics and infections of malaria vectors during large‐scale vector control interventions.     

The social organization of giraffes in Niger

The social organization of the last population of giraffes ( Giraffa camelopardalis ) in West Africa was studied between October 1996 and December 1997. Population size increased from 51 to 63 individuals during the study period. Groups were larger during the rainy season (mean group size 9.4) than during the dry season (mean group size 6; U = 4131; P < 0.01). Giraffes did not show strong preferential associations. Group types observed were similar to those expected on the assumption that associations are independent of sex and age. Inter-individual associations were low (mean simple ratio value = 0.1), with an individual associating with only half of its partners of the previous day. Young males interacted more frequently than other classes did. Agonistic interactions occurred mostly among males. Contact interactions (i.e. non-agonistic or sexual) occurred between both sexes and most age classes. Links between local communities, domestic animals, fauna and the environment suggest that environment and development cannot be dissociated in the sustainable exploitation of natural resources.     

旧石器时代考古与栖居及生计形态分析

由于打制石器本身所含的人类行为信息比较有限,我国旧石器时代考古研究应该引入文化生态学的理论方法,从宏观的生态位、中观的遗址域和微观的居住面分析来充分提炼古人类觅食方式和资源利用的信息。本文介绍了栖居(聚落)形态和遗址域概念的方法论及意义,并用墨西哥瓦哈卡河谷圭拉那魁兹的研究案例来说明这些概念在人地关系研究和农业起源研究中的重要性。文章呼吁旧石器时代考古研究要从低端的分类描述转向人类环境和行为的重建,以期令我们的研究水准跻身世界先进水平。     

Anopheles hervyi in Niger: no evidence for a role in Plasmodium falciparum transmission

Anopheles hervyi is an endemic mosquito species with a very limited spatial distribution in the south east of Niger. No new captures have been reported since the 1960s and its role in malaria transmission has not been studied. In the present study, the use of CDC light traps showed it to be much more abundant than previously found but there was no evidence to suggest it was a malaria vector in this region. The larval habitats have not been identified but the potential role of a saline lake in determining the distribution of this species is discussed.     

Net hunters vs. archers: Variation in women's subsistence strategies in the Ituri Forest

BaMbuti of the Ituri Forest, Zaire, employ two primary hunting techniques: net hunting, in which women routinely participate, and bow hunting, in which women rarely participate. We hypothesize that the value of women's labor devoted to different subsistence activities, combined with the exchange value of meat, will determine whether women participate in hunts. Field observations were conducted in four different areas: two exploited by archers and two by net hunters. Results indicate that women in nethunting areas earn more calories per unit time by hunting than by working in agriculturalists' gardens; whereas women in archer areas earn more calories by working for agriculturalists than by hunting. We found no significant difference in the composition or diversity of the forests exploited by net hunters and archers. The results are discussed in light of the longstanding debate concerning the factors that account for distribution of net hunting and archery in the Ituri Forest.     

Men's time allocation to subsistence work among the Ache of Eastern Paraguay

Quantitative data on men's time allocation among the Ache of Paraguay are presented. The data indicate that Ache men work almost 7 hours daily in direct food acquisition, which is the major daily activity. The amount of time Ache men work is compared with the amount reported for other modern hunter-gatherers and tribal horticulturalists. The characterization of hunter-gatherers as the original affluent society does not agree with currently available data. The results show high variance across societies, both hunting and horticultural, and suggest that time spent in subsistence work is not simply a function of food needs. We propose that the value of time spent in potential alternative activities must be considered in order to predict time spent in subsistence tasks.     

A framework for classifying subsistence production types of Nepal

This paper defines a four-tiered, hierarchical system for classifying subsistence production types in Nepal and uses the system to describe the subsistence communities of central Nepal. The system first divides Nepal into a grid of homogenous parts or cells, second, it divides, the cells into ridge-valley slope sequences, third, defines production types for the ridge-valley slope sequences, and, finally, distinguishes local variants of the production types. After describing these tiers, I apply these categories to the northern portions of the central and western development regions where I have done research. I then define how representatives of Nepal as a whole are the production types defined for the central and western development regions. Finally, the paper locates some completed studies within its framework.     

Role of Scutellonema clathricaudatum in etiology of groundnut growth variability in Niger

Variation in crop growth is an important limiting factor for groundnut production in Niger. Populations of Aphelenchoides sp., Ditylenchus sp., Helicotylenchus sp., Hoplolaimus pararobustus, Macroposthonia curvata, Paralongidorus bullatus, Scutellonema clathricaudatum, Telotylenchus indicus and Xiphinema parasetariae have been associated with groundnut crop growth variability. S. clathricaudatum, X. parasetariae and T. indicus were widespread and S. clathricaudatum was most abundant nematode. Population densities of S. clathricaudatum was always higher in the roots of poorly growing, chlorotic and stunted plants than in the roots of apparently healthy plants. A preplant population density of 1.3 S. clathricaudatum cm^-3 soil caused (p=0.05) reduction in plant growth of groundnut cv. 55–437. S. clathricaudatum was mainly confined to 0–15 cm soil depth at the time of planting in June and was not found below 45 cm depth at any time during the crop growth period. Soil application of carbofuran (10 kg a.i ha^-1) reduced the nematode population densities and resulted in vigorous and uniform crop growth. Higher Al and H-ion concentrations (0.50 meq 100 g^-1 soil) also was associated with poorly growing chlorotic seedlings. Symptoms of nematode-caused variable growth were evident 3 to 4 weeks after seedling emergence.Submitted as ICRISAT Journal Article No. 1141.     

A dynamic nonlinear optimization study of Mountain Pima subsistence technology

A dynamic nonlinear optimization analysis of subsistence patterns of the Mountain Pima of Chihuahua, Mexico, included requirements for adequate amounts of calories, calcium, vitamin A, vitamin C, and balanced protein. Two methods of incorporating nonenergy nutritional needs into a time minimization program were compared. The first was a constraint model with sharp boundaries between adequacy and fatality. The second involved multiplying the total work time by a series of nutrient indexing factors. Each factor was calculated as a function of the ratio between the recommended and actual rates of intake for all months and nutrients considered. Oxalate composition of some resources and seasonal variation in resource availability were taken into account. Two sets of data were analyzed, one for a year of adequate rainfall, the other for a year of severe drought. The predictions of the indexing model agreed more closely with observed intake patterns than did the predictions of the constraint model.     

Managing subsistence hunting in the changing landscape of Neotropical rain forests

Subsistence hunting has been a vital activity for local people across Neotropical rain forests (NRF). While providing a reliable source of protein, subsistence hunting also reflected the strong relationships that connected local people with the species and ecosystems in which they inhabited. However, the social and ecological context in which subsistence hunting can be sustainable has been altered. The relatively small groups that hunted in large and mostly undisturbed forests, using traditional weapons, have been replaced by a growing population using fragmented habitats and modern hunting methods. Thus, subsistence hunting is less likely to be sustainable, threatening the food security of local people and the persistence of species with critical roles in the functioning of NRF. Managing subsistence hunting in this changing context will require a more efficient combination of tools which might include banning the hunting of large and sensitive species, strengthening protected areas, alternatives to reduce the role of wildlife protein on local people's subsistence and, in some cases, voluntary resettlements of local people, from areas that could still be used as refuge for endangered species.     

Female subsistence strategies among Ache hunter-gatherers of Eastern Paraguay

Anthropologists have frequently proposed that sexual division of labor is produced by childcare constraints on women's subsistence work. We present data on the forest activities of Ache women that show that differences in parental investment partially account for variation in food acquisition among individual women. Data also suggest that childcare constraints are important in understanding the sexual division of labor.     

Efficiency,sufficiency, and recent change in Newfoundland subsistence horticulture

Traditional Newfoundland horticulture has been a subordinate and compensatory element of the subsistence sphere in a plural economy centered on fishing. Criticized as inefficient and ruinous to the land, this tuber-rootbrassica gardening has in fact been a valuable contribution to diet, is relatively efficient, and compensates for the inadequacies of land and weather. Field data from the Great Northern Peninsula, where some traditional practices persist, demonstrate that the practices conserve time and labor, and substitute massive applications of materials to assure a yield sufficient for household needs. The inefficiency in the tradition may be understood as a response to the constraints upon household labor and follows a kind of Leibig's law of the minimum. Recent changes in gardening practices reveal the dynamics of horticulture in the household's mixed economic strategy. As cash and land have become more common, they have been used to further reduce time while maintaining sufficiency.The research upon which this report is based was aided in 1982 by financial support from the American Philosophical Society and the State University of New York Research Foundation Faculty Awards program.     

Environmental variability and the fishery dynamics of the Okavango delta, Botswana: the case of subsistence fishing

The hydrological regime of the Okavango River Basin is the main driver of ecological change in the delta. The delta supports a small-scale fishery which is a source of livelihood for communities within its fringes. The fish resource is particularly important to subsistence fishers, who have limited access to socio-economic opportunities. However, fish availability is subject to 'concentration and dilution' effects because of the hydrological regime. As a copying strategy, fishers use a variety of fishing methods to effectively harvest the delta's fish community across all its trophic levels. This exploitation regime helps to maintain the delta's species diversity and only reduces fish biomass proportionally across the different trophical levels. Furthermore, fishers have developed different fish-processing techniques to preserve their harvest for low fishing season periods to cope with low food availability. The aim of this paper therefore, was to explore spatio-temporal variations in fish availability and to show how the delta's subsistence fishers cope with this dynamicity.