Stability and resilience in East African Pastoralism: The Rendille and the Ariaal of northern Kenya

The social organizations of two closely related nomadic pastoral societies of northern Kenya, the Rendille and Ariaal, are compared in the context of the relative constancy and variability of their herding environments. It is concluded that the application of Brooks and Yellen's model of stability and resilience in human populations is of value in understanding the impact of environmental constraints on social organization, but it is argued that other social features including the organization of labor and ownership of different livestock types directly bear on the differences between the Rendille and Ariaal.     

Absentee herd owners and part-time pastoralists: The political economy of resource use in northern Kenya

The prevalence of absentee herd ownership in Africa's pastoral areas is increasing. Its presence has important implications both for local resource management systems and for research programs that address pastoral ecology and related topics. This paper examines patterns of absentee herd ownership in the Baringo District of northern Kenya. This region has been the source of much debate regarding herder mismanagement of range lands. Three categories of absentee herd owners are discussed in the paper: (1) ranchers, (2) livestock traders, and (3) townsmen. It is suggested that the blame for some of the apparent resource mismanagement in the region may lie more with actors in these categories than with the pastoralists themselves. Data collected during an 18-month period in 1980–1981 on pastoral ecology, grazing patterns, and tenure institutions are presented in support of the argument. The paper concludes with a comparative analysis of contemporary resource management strategies in pastoral Africa, emphasizing that: (1) the Baringo case is not an isolated anomaly, and (2) a new orientation toward pastoral studies is warranted.     

Territorializing ethnicity: the imposition of a model of statehood on pastoralists in northern Kenya and southern Ethiopia

The idea of the nation state has penetrated Kenya and Ethiopia deeply at a level much below the ‘nation’ state. In the colonial period districts and grazing reserves were delineated according to perceived ‘tribal’ boundaries, which were often only created in the process. Ethnicity in that process was not invented (as has been claimed for other parts of Africa) but it has changed: it has acquired a territorial character of a new kind. Ethnic territoriality in the mind of policy makers combined with ideas of preservation of the range which modern range ecology would regard as misconceived. These ideas led to policies that restricted the range of movement of pastoral nomads. This paper draws a line from colonial policies to modern politics, in which territorial subdivision continues. This process seems to be guided the interests of self-styled elites, while the pastoralists are adversely affected by them.     

Normal vs. high‐protein weight loss diets in men: Effects on body composition and indices of metabolic syndrome

Objective:

This study assessed the effectiveness of a prescribed weight‐loss diet with 0.8 versus 1.4 g protein·kg^?1 day^?1 on changes in weight, body composition, indices of metabolic syndrome, and resting energy expenditure (REE) in overweight and obese men.

Design and Methods:

Men were randomized to groups that consumed diets containing 750 kcal day^?1 less than daily energy needs for weight maintenance with either normal protein (NP, n = 21) or higher protein (HP, n = 22) content for 12 weeks. The macronutrient distributions of the NP and HP diets were 25:60:15, and 25:50:25 percent energy from fat, carbohydrate, and protein, respectively. Assessments were made pre and post intervention. The subjects were retrospectively subgrouped into overweight and obese groups.

Results and Conclusion:

Both diet groups lost comparable body weight and fat. The HP group lost less lean body mass than the NP group (?1.9 ± 0.3 vs. ?3.0 ± 0.4 kg). The effects of protein and BMI status on lean body mass loss were additive. The reductions in total cholesterol, HDL‐C, triacylglycerol, glucose, and insulin, along with LDL‐C, total cholesterol‐to‐HDL‐C ratio, and HOMA‐IR, were not statistically different between NP and HP. Likewise, macronutrient distributions of the diet did not affect the reductions in REE, and blood pressure. In conclusion, energy restriction effectively improves multiple clinical indicators of cardiovascular health and glucose control, and consumption of a higher‐protein diet and accomplishing weight loss when overweight versus obese help men preserve lean body mass over a short period of time.

     

Sedentism, seasonality, and economic status: A multivariate analysis of maternal dietary and health statuses between pastoral and agricultural Ariaal and Rendille communities in northern Kenya

This paper examines longitudinal data to assess the effects of the recent transition from pastoralism to sedentary agriculture for Ariaal and Rendille mothers in northern Kenya. Dietary, morbidity, and anthropometric data resulting from bimonthly repeated surveys of the pastoral community of Lewogoso and the sedentary agricultural community of Songa, covering the period from September 1994-July 1995, were used to test two hypotheses: 1) that sedentism is associated with changes in diet, seasonality, morbidity, and socioeconomic differentiation, and 2) that these changes affect maternal body composition. The first hypothesis is partly supported, with starch replacing milk in the sedentary diet. Repeated-measures multivariate analysis of variance revealed no seasonal effects for diet in the agricultural sample, while starch consumption was significantly affected by seasonality for the pastoral sample. The agricultural community also featured economic dietary disparities favoring wealthier mothers, while no such effect was found in the pastoral community. However, no seasonal or economic effects were found for morbidity patterns in either sample. The second hypothesis is also partially supported, as a generalized estimating equations analysis revealed differences in the way diet and economic strata influence maternal anthropometric values. Economic status was significantly associated with maternal arm-fat area in Lewogoso. Milk was a significant factor associated with maternal weight and arm-muscle area in Songa. These findings are discussed in light of development policy implications.     

Transferability of bioassessment indices among water body types and ecoregions: A California experiment in wetland assessment

Biological assessment of aquatic resources requires the availability of bioassessment tools that work in all waterbody types and regions of interest. Developing new assessment tools may require several years of data collection and substantial investment of resources, which may not be an option for some aquatic resource managers. Adapting tools developed for different regions or wetland types may be an attractive alternative to developing new indices, provided they work well in the novel setting. In this study, we explore the transferability of two bioassessment indices for application to depressional wetlands in California, which are wetland type of management concern but for which bioassessment tools don’t currently exist. We tested the applicability of a depressional wetland invertebrate index of biotic integrity (IBI) developed in the San Francisco Bay region of northern California for application in the drier regions of southern California (i.e. geographic transferability), and the ability to apply a riverine benthic diatom IBI to benthic diatoms in depressional wetlands (i.e. water body type transferability). We evaluated the accuracy and responsiveness of the existing Indices for use in depressional wetlands and refined reference definitions and recalibrated thresholds relative to stressor gradients to maximize index performance. Performance of the adapted indices was compared to that of an existing habitat assessment tool (the California Rapid Assessment Method; CRAM) that has been developed for statewide application of depressional wetlands. Finally, we demonstrate application of the revised indices for ambient assessment of depressional wetland condition in southern California. Recalibrating both the macroinvertebrate and diatom indices to reference thresholds based on nutrient concentrations resulted in lower coefficient of variation among reference sites, greater differentiation between reference and non-reference and stronger relationship with stressors than when reference thresholds were based on landscape disturbance. Overall, the simple adjustment of the reference definition allowed us to transfer the indices with no structural changes to the metrics. This approach can facilitate future index adaptations that allow practitioners to include waterbody types for which there is no current index into routine biomonitoring programs.     

Impact of nutrition on oocyte quality: cumulative effects of body composition and diet leading to hyperinsulinemia in cattle

The present study sought to assess the combined effects of body composition and diet (level of feeding) on the postfertilization developmental potential of oocytes recovered from heifers using ultrasound-guided transvaginal follicular aspiration and to relate oocyte quality to the metabolic status of these animals. By collecting oocytes on repeated occasions spanning several weeks, it was possible to assess the cumulative effects of changes in nutritional status on oocyte quality over this period. Twenty-four heifers of low and moderate body condition were placed on one of two levels of feeding (equivalent to once or twice the maintenance requirements of these animals). Oocytes were recovered at two defined time points within each of three successive estrous cycles and were matured, fertilized, and cultured to the blastocyst stage in vitro. The results show that the effect of feeding level on oocyte quality is dependent on the body condition of the animal, with the high level of feeding being beneficial to oocytes from animals of low body condition but detrimental to oocytes from animals of moderately high body condition. Furthermore, the effects of high levels of feeding on oocyte quality were cumulative, with blastocyst yields for relatively fat heifers on twice the maintenance requirement deteriorating with time relative to yields for relatively thin heifers on the same level of feeding. Finally, a significant proportion of the moderately fat animals on the high level of feeding were hyperinsulinemic, and we show, to our knowledge for the first time in ruminants, that this condition is associated with impaired oocyte quality.     

Effect of the melanocortin-3 receptor Thr6Lys and Val81Ile genetic variants on body composition and substrate oxidation in Chilean obese children

Mice genetically deficient in the melanocortin-3 receptor gene are characterized by normal body weight, increased body fat, mild hypophagia, reduced locomotor activity, and increased respiratory quotient compared with wild-type mice. In humans, the 6Lys–81Ile haplotype of melanocortin-3 receptor (MC3R) gene has been associated with childhood obesity, higher body fat percentage, and reduced fat oxidation compared to non-carriers. The aim of this study was to evaluate the association between MC3R 6Lys–81Ile haplotype with body composition and substrate oxidation in response to moderate exercise in obese children. Eight Chilean obese children (aged 8–12) carriers of MC3R 6Lys–81Ile haplotype were compared with eight age–gender-matched obese non-carriers. Children were identified through a previous cross-sectional study on genetic determinants of childhood obesity (n = 229). Genotypes for MC3R Thr6Lys and Val81Ile were determined by polymerase chain reaction–restriction fragment length polymorphism. Body composition was assessed by the four-compartment model (dual-energy X-ray absorptiometry, total body water by the deuterium dilution technique, and total fat mass by air-displacement plethysmography). Substrate oxidation was assessed by indirect calorimetry in response to moderate exercise (60% VO_{2 max}). Wilcoxon matched-pairs test was used to compare quantitative variables. No significant differences among carriers and non-carriers were found in anthropometrical and body composition measurements. The Carriers of the 6Lys–81Ile haplotype showed higher respiratory quotient (p = 0.06) and a significantly higher glucose oxidation (p = 0.01) compared with non-carriers after standardization for fat-free mass. Our results are consistent with a possible participation of MC3R 6Lys–81Ile variants in glucose oxidation in response to moderate exercise.     

Age variations in anthropometric and body composition characteristics and undernutrition among female Bathudis: a tribal population of Keonjhar District, Orissa, India

A cross-sectional study of 183 female Bathudis, a tribal population of the Keonjhar District, Orissa, India, was undertaken to investigate age variations in anthropometric and body composition characteristics and nutritional status. The subjects were categorized into three age groups: < or =30 years, 31-50 years, >50 years. Height, weight, circumferences and skinfolds data were collected. Body mass index (BMI) and several body composition variables and indices were derived using standard equations. The results revealed that there existed significant negative age variations for most of the anthropometric and body composition variables and indices. Correlation studies of age with these variables and indices revealed significant negative correlations. Linear regression analyses revealed that for all variables, age had a significant negative impact. Studies on the nutritional status of these women revealed that with increasing age, there was an increase in the frequency of undernutrition. In conclusion, this study demonstrated that among Bathudi women, age was significantly negatively related with anthropometric and body composition variables and indices. Moreover, with increasing age, the level of undernutrition increased.     

Changes in elemental composition of fertilized and unfertilized northern pike (Esox lucius) eggs incubated in buffer with and without dimethyl sulfoxide: An X-ray microanalysis study

Fertilized and unfertilized eggs from the northern pike (Esox lucius) were incubated 2 hr in buffer with 0 and 10% (v/v) dimethyl sulfoxide and then quickly frozen in the wells of aluminum blocks submerged in liquid nitrogen. Control eggs and ovarian fluid were similarly frozen immediately after collection. The frozen eggs were sectioned, freeze dried, mounted on stubs, and carbon coated. X-ray microanalysis was used to determine changes in element levels and dimethyl sulfoxide (Me₂SO) penetration in the zona radiata, cytoplasm, cortical alveoli, and egg yolk. Unfertilized eggs incubated without Me₂SO showed decreased levels of Na, Cl, and K in the zona radiata; fertilized eggs, incubated without Me₂SO showed decreased levels of Na, P, and Cl in the zona radiata and increased levels of K in the cytoplasm; unfertilized eggs, incubated with 10% Me₂SO showed decreased Na and Cl in the zona radiata, decreased K in the cytoplasm and increased K in the cortical alveoli; fertilized eggs incubated in buffer with 10% Me₂SO showed decreased levels of Na, P, Cl, and K (zona radiata), P, Cl, and K (cytoplasm), Na (yolk), and increased Cl in the yolk (all P<.01). Me₂SO (v/v) levels reached 1.5-3.1% in the zona radiata, 0-3.2% in cytoplasm, 2.3-8.7% in cortical alveoli, and 0-1.6% in the yolk. Unfertilized eggs showed more Me₂SO penetration than fertilized eggs.     

The effects of controlled propagation on an endangered species: genetic differentiation and divergence in body size among native and captive populations of the Socorro Isopod (Crustacea: Flabellifera)

The endangered Socorro Isopod, Thermosphaeroma thermophilum, is endemic to a single thermal spring in Socorro, NM. This species is cannibalistic, with males more cannibalistic than females, and with females and juveniles more vulnerable than males as prey. In 1990, the New Mexico Department of Game and Fish, created the Socorro Isopod Propagation Facility (SIPF) near the natural habitat, Sedillo Spring (SS), to increase total population size and to examine the effects of habitat heterogeneity on population growth. We report the genetic and morphological effects of this experiment, using the natural population as a control. Captive subpopulations experienced bottlenecks of known intensity and duration, as well as different intensities of cannibalism. Using 57 AFLP markers, we show that in 6 years (1990–1996), captive subpopulations diverged significantly from the natural population. Also during this 6-year period, body lengths of captive isopods diverged nearly 2-fold from the natural population, evidently because cannibalism and thus selection favoring large size was more intense in captive subpopulations than in nature. This hypothesis is supported by the fact that cannibalism and the apparent response to selection on body size became variable among captive subpopulations when physical structure was added to three of the four SIPF pools in April 1997. As expected if cannibalism was the source of selection for large body size, by August 1998 (15 months = 7–8 generations), the rate at which body size increased became inversely proportional to the amount of physical structure within pools. Although we are unable to separate the specific effects of population subdivision and cannibalism, our results show that these conditions in combination caused rapid changes in genetic variation and the external morphology of these captive subpopulations. Our results have important implications for future attempts to manage and propagate endangered species.