Acacia trees on the cultural landscapes of the Red Sea Hills

This paper examines interactions between five pastoral nomadic culture groups of the Egyptian and Sudanese Red Sea Hills and the acacia trees Acacia tortilis (Forssk.) Hayne subsp. tortilis and subsp. raddiana growing in their arid environments. A. tortilis is described as a keystone species both ecologically and culturally: the trees play such critical roles in ecosystems and social groups that their removal would greatly impact both systems. Interviews in the field with the Semitic, Arabic-speaking Ma‘aza and Ababda, and the Cushitic, Beja, Bidhaawyeet-speaking Bishaari, Amar Ar and Hadandawa nomads probed the cultural and ecological contexts of acacias in pastoral nomadism, revealing deep insight into traditional ecological knowledge and traditional perceptions and uses of the trees. The paper describes how this knowledge guides pastoral decision-making, with acacias as a particularly critical component of the pastoral livelihood in both normal and stressful circumstances. A. tortilis is the most important reliable vegetation resource for nomads while also providing fuel and other useful products, ecosystem services for people and animals, and increased biodiversity by providing diverse microhabitats and resources for other species. We describe aspects of kinship, territorial organization, spiritual beliefs and tribal law underlying the significance of trees on the cultural landscape. We discuss environmental and economic challenges to human/tree relationships and to pastoral livelihoods. We challenge views of nomads as agents of ecological destruction, and propose maintenance and restoration of traditional pastoralism as viable alternatives in dryland development.     

Interstitial but Resilient: Nomadic Shepherds in Piedmont (Northwest Italy) Amidst Spatial and Social Marginalization

Mobility, nomadic pastoralists’ main adaptive strategy, has been compromised by agricultural expansion and rangeland fragmentation, among other factors, in many pastoral contexts. Among nomads’ coping strategies, is re-shaping mobility in shrinking grazing grounds. Through semi-structured interviews, we examine adaptation and resilience to the effects of increasingly intensive land use and marginalization focusing on Alpine nomadic pastoralists in Piedmont, Northwest Italy. Our results show that Alpine nomads access a wide variety of grazing grounds through a web of social relations with multiple stakeholders, acting in the interstices of mainstream society and navigating marginal contexts: geographically, they use fallow, abandoned, and post-harvest plots; economically and socially, they interact with other marginal groups (e.g., migrants) and are stigmatized by diverse sectors of society. This use of interstitial spaces is in itself a form of adaptation that is taking place in diverse geographical contexts as nomads reconfigure their mobility and social relations to access the scattered pieces of land left unused by industrial, agricultural, and conservation land uses.     

Subsistence patterns as regulators of vital events. The case study: Seasonality of marriages and conceptions in historical times in Central-Southern Apennines (Abruzzo region)

The study of biological microdifferentiation of human populations is usefully integrated by the analysis of the biodemographic parameters that provide information on the ecological context in which a population developed specific subsistence models. Seasonality of marriages and births are good parameters of the different “traditional' lifestyles, since they both are influenced by cultural traditions, demographic characteristics, socio-economic conditions, environmental factors, working activities and loads, the latter possibly resulting in a limiting factor of the fertility's physiological functions. An indirect way to estimate such limiting factor in historical societies is by relating seasonality of both vital events to natality rates. The present research investigated seasonality of 19,867 records of Marriages and 59,360 records of Baptisms as well as natality rates in several communities of the Provinces of Teramo and L'Aquila (Abruzzo, Italy) in the 19^th century. Results show stable patterns of seasonality of both marriages and baptisms. Marriages display one model of seasonality typical of agricultural societies, with several sub-models, and a second developed by pastoral groups. The correlation between seasonality of marriages and that of conceptions is high in pastoral communities, and negative in agricultural groups. Gross natality rates average35×1000 in agricultural societies and27×1000 in pastoral groups thus suggesting that pastoralism acted as a regulator of reproduction.     

A Comparison of Health Complaints of Settled and Nomadic Turkana Men

This article examines the health complaints of settled and nomadic Ngisonyoka Turkana of northwest Kenya. Samples of 152 nomadic and 124 settled men, aged 14 and over, were surveyed about their health status. The general pattern of disease reported concurs with previous studies of health among Turkana; that is, the primary complaints are respiratory tract infections and eye infections. The settled Turkana reported more severe complaints and higher rates of infectious disease than the nomads, including a significantly higher frequency of cold with cough, eye infection, and chest infection. Although the settled males as a group had slightly higher body mass index and other measures of body fat than the nomadic group, none of these indicators of body composition were predictive of health complaints. Observed differences in health patterns are possibly related to differences in dietary composition, exposure to pathogens associated with population density and environmental pollution, physical activity patterns, and psychosocial stress.     

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.     

The ecological interdependence of diet and disease in tribal societies.

Observations among nomads suggest there is a strong ecological interdependence of diet and disease in tribal societies which favors survival of man. This relationship may be disrupted by changes in diet to conform to the highly productive technology of the West. Such changes may result in intensification of indigenous disease and in the transfer of disease characteristics of Western societies. To prevent these consequences, relief feeding and long-term attempts to upgrade nutrition should be carried out with traditional foods wherever possible.     

Periodic climate cooling enhanced natural disasters and wars in China during AD 10–1900

Recent studies have linked climatic and social instabilities in ancient China; the underlying causal mechanisms have, however, often not been quantitatively assessed. Here, using historical records and palaeoclimatic reconstructions during AD 10–1900, we demonstrate that war frequency, price of rice, locust plague, drought frequency, flood frequency and temperature in China show two predominant periodic bands around 160 and 320 years where they interact significantly with each other. Temperature cooling shows direct positive association with the frequency of external aggression war to the Chinese dynasties mostly from the northern pastoral nomadic societies, and indirect positive association with the frequency of internal war within the Chinese dynasties through drought and locust plagues. The collapses of the agricultural dynasties of the Han, Tang, Song and Ming are more closely associated with low temperature. Our study suggests that food production during the last two millennia has been more unstable during cooler periods, resulting in more social conflicts owing to rebellions within the dynasties or/and southward aggressions from northern pastoral nomadic societies in ancient China.     

Determinants of birth interval in a rural Mediterranean population (La Alpujarra, Spain)

The fertility pattern, in terms of birth intervals, in a rural population not practicing contraception belonging to La Alta Alpujarra Oriental (southeast Spain) is analyzed. During the first half of the 20th century, this population experienced a considerable degree of geographical and cultural isolation. Because of this population's high variability in fertility and therefore in birth intervals, the analysis was limited to a homogenous subsample of 154 families, each with at least five pregnancies. This limitation allowed us to analyze, among and within families, effects of a set of variables on the interbirth pattern, and to avoid possible problems of pseudoreplication. Information on birth date of the mother, age at marriage, children's birth date and death date, birth order, and frequency of miscarriages was collected. Our results indicate that interbirth intervals depend on an exponential effect of maternal age, especially significant after the age of 35. This effect is probably related to the biological degenerative processes of female fertility with age. A linear increase of birth intervals with birth order within families was found as well as a reduction of intervals among families experiencing an infant death. Our sample size was insufficient to detect a possible replacement behavior in the case of infant death. High natality and mortality rates, a secular decrease of natality rates, a log-normal birth interval, and family-size distributions suggest that La Alpujarra has been a natural fertility population following a demographic transition process.     

Dynamic Mutual Adaptation: Human-Animal Interaction in Reindeer Herding Pastoralism

Most of the existing anthropological literature that recognizes human-animal interaction as being at the core of nomadic pastoralism focuses on nomads as the only active agents of this interaction. Nomads interact with their animals by either adapting their actions to animal behavior or by changing this behavior in ways to suit them. Based on empirical material from two groups of reindeer herding nomads in northern Russia, we suggest that human-animal interaction in nomadic pastoralism can be better understood as being the result of a dynamic mutual behavioral adaptation. In the process of this adaptation, animals change their behavior in response to the herders’ actions, which in turn leads to a responsive change to herders’ patterns of actions, etc. We argue that this approach can account for the differences in both animal behavior and herding technologies across nomadic pastoralist cultures, as well as for some of the divergent developments within these cultures.     

Differential mortality in Turkana agriculturalists and pastoralists

Nomadic pastoral populations appear to have much lower rates of growth than the otherwise very high growth rates now characteristic of populations in developing nations. Because dramatic declines in infant mortality have been a primary contributor to increased population growth rates in these countries, it has been assumed that nomadic pastoral populations are still characterized by high levels of mortality in the first few years of life. Few studies, however, have been undertaken to estimate demographic parameters for nomadic pastoral populations, and even fewer of a comparative nature have been undertaken to document the impact of subsistence strategy on demographic processes. This study compares indirect childhood mortality estimates for Turkana nomadic pastoralists with childhood mortality in a settled agricultural group within the same population and finds that pastoralists have substantially higher levels of mortality. Based on the childhood mortality estimates, model life tables are selected for pastoral and agricultural groups from which values for mean life expectancy and infant mortality are estimated and compared. Recent improvements in primary health care for the settled agricultural group are ruled out as being an important cause of their lower mortality levels, and some aspects of life-style associated with subsistence strategy are discussed as likely determinants of the mortality differences.     

International borders and range ecology: The case of Bedouin transborder grazing

Recent research suggests that, under unconstrained human circumstances, pastoral nomads within arid environments have at their disposal means of evading ecological stress that could impel them to cause damage to their grazing and land resources. The Israeli-Egyptian border has imposed a severe constraint upon the range management strategy of the Bedouin whose traditional territory it bisects. The border forced them to exert an increased pressure upon local resources. Considerable damage was thus caused to the perennial vegetation cover (both macrophytes and microphytes) and to the structure of sand dunes on the Egyptian side of the border, with opposite effects on the Israeli side to which the Bedouin had no access. This case study adds a further dimension to the discussion of range management by pastoral nomads in arid and semi-arid areas.     

Growth of nomadic and settled Turkana infants of northwest Kenya

Turkana tribespeople reside in a semi-arid savanna ecosystem in northwest Kenya. For over a decade, Ngisonyoka Turkana nomads have been studied within a multidisciplinary framework that embraces ecology, anthropology, and human population biology. Original research objectives of the South Turkana Ecosystem Project were to study nomads longitudinally and within the context of the dry savanna ecosystem. These objectives have been expanded to incorporate settled Turkana who were nomads in the recent past, but who, for a variety of reasons, have taken up a life of sedentary cultivation. The research described here focused on comparisons of growth patterns of nomadic and settled infants from birth to 24 months of age. Infants were measured (recumbent length, weight, head circumference, arm and calf circumference, and selected skinfolds) in 1989 and 1990. Settled infants were slightly longer, but nomadic infants were heavier and fatter. Head circumferences were the same. Some variation was observed by season and year of measurement (from comparative surveys). Both groups showed pronounced weight faltering after 6 months of age when compared with U. S. NCHS reference values. Head circumference faltering was moderate and recumbent length faltering was only slight after 12 months of age. Comparisons of Turkana infant growth in the two populations can contribute indirectly to a better understanding of infant nutritional status, probable morbidity, and other factors, some of which may be linked to female reproduction. © 1993 Wiley-Liss, Inc.     

Tiller demography in seashore populations of Agrostis stolonifera,Festuca rubra and Poa irrigata

Abstract. The dynamics of tillers in natural populations of three cohabiting perennial grass species, Agrostis stolonifera, Festuca rubra and Poa irrigata (= Poa pratensis ssp. irrigata) were studied for five years in a Baltic seashore meadow. The process of tiller population maintenance was very dynamic. Both birth and death rates of tillers were high, particularly in A stolonifera, and the turnover rate of the populations was high. Recruitment was mainly by vegetative tillers, produced continuously throughout the growing season. The proportion of flowering tillers was low, but varied between years. Considerable year-to-year variation was also found in birth and death rates. Despite this between-year variation and the differences found between species in flowering frequency, pattern of survivorship and tiller longevity, population sizes of the species remained relatively constant.     

Ageing index evolution in the Spanish population

Official statistics allow an analysis of the ageing index changes in the Spanish population from 1930 to 1975. During this period the ageing index values doubled from 19.11 to 38.60, the maximum increase having occurred between 1950 and 1960. Both birth and death rates lowered during the 45 years studid; however, the death rate decreased twice as fast. The natural increase rise was thus mainly due to a lower death rate. These data can explain a part of the ageing index transformation. By province, the ageing index range increased three-fold from 1930 to 1975. Some provinces showed an elevated index and others a reduced one. After 1960, extensive areas of inland Spain showed an older age structure because of emigration to industrialized towns.     

Women's changing economic roles with pastoral sedentarization: Varying strategies in alternate Rendille communities

The trend of pastoral sedentarization in Africa presents new economic opportunities to women through the sale of dairy products, agricultural produce, and labor. This study of Rendille of northern Kenya shows a variety of economic strategies pursued by women in nomadic pastoral, settled agro-pastoral, and town communities. Results of household budgets and interviews with married women indicate that urban centers attract both wealthier Rendille women selling milk and poorer women engaged in wage-labor and petty commodity trade; time allocation data shows that women living in towns work as strenuously as those in pastoral communities, while men in towns work less than in pastoral communities and less than women in both communities; and anthropometric data of women and children suggest that increases in women's income may have a beneficial effect on the nutrition and well-being of their children.     

The Tribe as a Unit of Subsistence: Nomadic Pastoralism in the Middle East

Among Middle Eastern pastoral nomads some "tribes" can best be described as "units of subsistence": they exploit an area providing multiannual subsistence. Tribesmen sometimes control this area; more usually they control part of it and share the rest with other nomads and with settled people. Small corporate groups afford the tribesman security and, through genealogical links, mediate his formal membership of the tribe. The unit of subsistence is articulated mainly by networks of institutionalized relationships. Corporate groups join forces only for defense, and then their alliances cut across tribal lines. Under external pressure the unit of subsistence may develop formal leadership and a small standing militia. This administrative setup is in the literature often associated with the corporate groups and called "tribe." While coexisting with a unit of subsistence, this "tribe" is not necessarily identical with it in area or population . [ecology, genealogies, Middle East, pastoral nomads, tribe]     

Pregnancy outcome for nomadic Turkana pastoralists of Kenya

The outcome of an individual pregnancy is a key component of overall reproductive success and is strongly influenced by environmental, behavioral, and biological variation within populations. This prospective study examined the outcomes of 68 pregnancies among nomadic Turkana of Kenya from July 1993 to July 1994. A total of 12 women experienced pregnancy losses, and 3 women experienced live births with a subsequent perinatal death. The following characteristics are associated with increased risk for experiencing a fetal or perinatal death: severe morbidity episodes, shorter nonpregnant intervals, lower third-trimester weight, higher third-trimester summed skinfolds but limited third-trimester reduction in summed skinfolds, and higher activity levels late in gestation. Turkana newborns measured within 48 hr of birth (n = 19) weighed an average of 2,860 +/- 640 g and had a mean ponderal index of 2.72 +/- 0.46. Variation in birth weight was predicted by preterm delivery, delivery during the wet season, and maternal morbidity levels. Birth length averaged 50.8 +/- 6.8 cm and was positively influenced by full term delivery, better maternal health, and birth during the dry season. These results suggest complicated pathways linking the physical environment, subsistence requirements, heterogeneity in maternal fitness, behavior, and pregnancy outcome. The results augment the larger picture of reproductive success for Turkana nomads who live in a highly variable savanna environment.     

Dynamics of an age‐structured population drawn from a random numbers table

I constructed age‐structured populations by drawing numbers from a random numbers table, the constraints being that within a cohort each number be smaller than the preceding number (indicating that some individuals died between one year and the next) and that the first two‐digit number following 00 or 01 ending one cohort’s life be the number born into the next cohort. Populations constructed in this way showed prolonged existence with total population numbers fluctuating about a mean size and with long‐term growth rate (r) ≈ 0. The populations’ birth rates and growth rates and the females’ per capita fecundity decreased significantly with population size, whereas the death rates showed no significant relationship to population size. These results indicate that age‐structured populations can persist for long periods of time with long‐term growth rates of zero in the absence of negative‐feedback loops between a population’s present or prior density and its birth rate, growth rate, and fecundity, contrary to the assumption of density‐dependent regulation hypotheses. Thus, a long‐term growth rate of zero found in natural populations need not indicate that a population’s numbers are regulated by density‐dependent factors.     

A population study ofScapholeberis rammneri Dumont and Pensaert (Cladocera: Daphniidae)

Scapholeberis rammneri does not hatch at temperatures below 19°C, and its temperature optimum, as derived from field and culture data, is situated close to 21°C. In a small pond, free of vertebrates and with few insects present, its population dynamics were governed entirely by temperature-dependent parameters, such as reproductive success and fertility. From cultures conducted at four different temperatures, it was found that culture reproductive success (the fraction of females in a culture that reproduce at least once before death occurs) leads to an estimate of net birth rates, and its complement (the fraction of females that fail to reproduce before death occurs) produces an estimate of mortality due to natural causes. Because in the pond predation was insignificant, postembryonic culture mortality provides a reasonable estimate of field mortality due to natural causes as well. When postembryonal culture mortality is substracted from culture birth rates, a net rate of population increase somewhat lower than that in the pond is observed. Because of strong temperature effects, this transfer of culture data to field conditions strictly applies only to early summer conditions: an expandingScapholeberis population, and fairly constant field temperatures close to the temperature optimum of the species.