Pre-historic cucurbits from the Valley of Oaxaca

About 180 specimens of cucurbits were recovered from the Guila Naquitz Cave in the Valley of Oaxaca, Mexico, from strata dated at 8750-7840 B.C. to 1500 A.D. by Carbon- 14 analyses. 4 Almost 60% of the cucurbit specimens were of wild species of Cucurbita. A single seed may be that of the perennial squash or fig- leaf gourd, C. ficifolia Bouch é. All other cultivated squash material was C. pepo L., the summer squash. Cucurbita pepo prefers cool, dry environmental conditions. This suggests that farmers utilized the cave on a seasonal basis, because cultivars of C. pepo mature later and store better than those of C. moschata Poir. or C. mixta Pang., which would normally be the species expected to be cultivated at this latitude. Specimens of bottle gourd, Lagenaria siceraria (Mol.) Standl., were comparatively rare and comprised only 10% of the total. The scarcity of bottle gourd remains suggests that these gourds were not important for containers and household, use even in preceramic levels, or that they simply did not break many of their vessels during the limited time they occupied the cave. A second possibility is that agriculture was carried out at higher and cooler elevations, which C. pepo prefers but which are unfavorable for Lagenaria. A few Apodanthera seeds were found at all levels.     

Prehispanic colonization of the Valley of Oaxaca,Mexico

A decade ago in a seminal monograph, Anne Kirkby proposed a model of colonization for the prehispanic Valley of Oaxaca, Mexico, in which settlement location was determined by the distribution of prime agricultural land. The model was tested against the corpus of known prehispanic settlements and tentative support was found. In the years since this study, a systematic archeological settlement pattern project was completed, making a more adequate test of the model possible. Reexamination of the colonization process suggests that, although agricultural considerations were important, they were less determinant of settlement location than had been implied previously. The adoption of a broader perspective toward regional colonization is suggested.     

Health and agricultural intensification in the prehistoric Valley of Oaxaca, Mexico

The effects of agricultural intensification on health are examined in prehistoric populations of the Valley of Oaxaca, Mexico. Agriculture was practiced in the Valley of Oaxaca by the beginning of the Early Formative period (ca. 1400 B.C.), and had intensified by the Late Formative (ca. 500 B.C.). Skeletal remains from 14 archaeological sites in the Valley are pooled by temporal affiliation into a nonintensive agriculture group (1400-500 B.C.) and an intensive agriculture group (500 B.C.-1400 A.D.). The health effects of agricultural intensification are assessed by comparing the frequency of periosteal reactions, cribra orbitalia, and enamel hypoplasia between the intensive and nonintensive agricultural groups. Overall, no significant differences (alpha = 0.05) are found between the nonintensive and intensive groups. Power analyses of the chi-square tests indicate that the tests have a high probability of rejecting a false null hypothesis. The intensification of agriculture does not appear to have had a deleterious effect on the health of the prehistoric population of the Valley. The differences between this study and previous studies of health and agricultural development may be explained by differences between the processes of intensification and development or by differences between primary and secondary centers of agricultural development.     

Growth of rural and urban children in the Valley of Oaxaca,Mexico

Weight, stature, arm circumference, and the triceps skinfold were measured in 1,410 school children, 6 through 14 years of age, from two urban colonias in the city of Oaxaca de Juarez (n = 479), and from two rural Ladino (n = 467) and two rural Zapotec (n = 464) communities in the Valley of Oaxaca in southern Mexico. Children from rural Ladino communities and urban colonias are significantly taller, heavier, and more muscular than children in rural Zapotec communities. The differences between rural Ladino and urban colonia children favor the former, particularly for weight and stature. These observations thus suggest (1) that children in the rural, indigenous communities in the Valley of Oaxaca are relatively undernourished compared to children in Ladinoized and urban communities, and (2) that rural-to-urban migration does not necessarily result in improved growth status.     

Epidemiologic transition in an isolated indigenous community in the Valley of Oaxaca, Mexico

The objective of the present study is to analyze age-specific mortality in a rural indigenous community in the throes of a secular increase in size in the Valley of Oaxaca, southern Mexico, over 30 years, 1970-1999. Variation in mortality by age group was analyzed over time for evidence of an epidemiological transition. The seasonal rain pattern in the Valley of Oaxaca (83% from May through September) was evaluated for its relationship with mortality in wet and dry months. Mortality and causes of death changed markedly over the 30-year interval. Infant and preschool mortality, overall mortality, and causes of death changed from the 1970s through the 1990s. Prereproductive deaths (<15 years) predominated in the 1970s and were largely due to gastrointestinal and respiratory diseases, with periodic outbreaks of measles. Deaths of adults 65+ years predominated in the 1990s and were largely due to degenerative diseases usually associated with aging. The marked changes in age and causes of death over the three decades (epidemiologic transition from Stage I to Stage II) occurred concurrently with significant secular increases in body size in children, adolescents, and young adults, highlighting improved health and nutritional conditions in the community which is in early Stage II of the demographic transition. The demographic transition to Stage II is a leading indicator (15-25 years lag) for the onset of the secular trend, while the epidemiologic transition to Stage II is a predictor that the secular increase is in process in the study community.     

Demographic Diversity and Change in the Central American Isthmus

Demographic Diversity and Change in the Central American Isthmus. Anne R. Pebley and Luis Rosero-Bixby. eds. Santa Monica, CA: RAND, 1997.736 pp.     

Genetic drift and natural selection in an isolated Zapotec-speaking community in the Valley of Oaxaca, southern Mexico

Genetic drift and natural selection were analyzed in a genetically isolated Zapotec-speaking community in the Valley of Oaxaca, southern Mexico. Moderately intense genetic drift and selection potentials were found. Potential for drift was related to (1) the small effective size of the population, and (2) the exceptionally low number of migrants into the population. Potential for selection was due to (1) an unusually high variance in fertility, and (2) a high contribution of prereproductive mortality. Significant potential for genetic evolution was found due to genetic drift and natural selection.     

Population, Gender and Politics: Demographic Change in Rural North India

Population, Gender and Politics: Demographic Change in Rural North India. Roger Jeffery and Patricia Jeffery. New York: Cambridge University Press, 1997. 278 pp.     

Demographic Sensitivity of Population Change in Northern Bobwhite

Abstract: The northern bobwhite (Colinus virginianus) is an economically important gamebird that is currently undergoing widespread population declines. Despite considerable research on the population ecology of bobwhites, there have been few attempts to model population dynamics of bobwhites to determine the contributions of different demographic parameters to variance of the finite rate of population change (Λ). We conducted a literature review and compiled 405 estimates of 9 demographic parameters from 49 field studies of bobwhites. To identify demographic parameters that might be important for management, we used life-stage simulation analyses (LSA) to examine sensitivity of Λ to simulated variation in 9 demographic parameters for female bobwhites. In a baseline LSA based on uniform distributions bounded by the range of estimates for each demographic parameter, bobwhite populations were predicted to decline (Λ = 0.56) and winter survival of adults made the greatest contribution to variance of Λ (r² = 0.453), followed by summer survival of adults (r² = 0.163), and survival of chicks (r² = 0.120). Population change was not sensitive to total clutch laid, nest survival, egg hatchability, or 3 parameters associated with the number of nesting attempts (r²<0.06). Our conclusions were robust to alternative simulation scenarios, and parameter rankings changed only if we adjusted the lower bounds of winter survival upwards. Bobwhite populations were not viable with survival rates reported from most field studies. Survival rates may be depressed below sustainable levels by environmental conditions or possibly by impacts of capture and telemetry methods. Overall, our simulation results indicate that management practices that improve seasonal survival rates will have the greatest potential benefit for recovery of declining populations of bobwhites.     

Demographic Analysis of a Disjunct Population of Froelichia floridana in the mid-Ohio River Valley

Froelichia floridana (cottonweed) occurs as a disjunct population along the Ohio River in southeastern Ohio. The anomalous occurrence of F. floridana in this area has led to its designation as a state endangered species and a management regime to maintain the habitat conditions in which it occurs. As part of this effort, a restoration site was established on public lands in 1984 from seed collected in areas threatened by development. This study seeks to determine the demographic characteristics of this species in the restored and non‐restored managed sites to provide basic ecological information regarding life history parameters and to judge the effectiveness of the restoration. For two years (1997–1998) we collected information on seed bank abundance, field seed germination, plant survivorship, and seed production to create a stage‐based transition matrix model. The model suggests that population growth and abundance as assayed by λ (rate of increase) are stable to declining and are similar between the restoration and natural sites. A reduction in competition had a positive effect on population growth. Elasticity analysis showed that plants germinating earlier in the spring and becoming established as an early cohort contributed a greater level of reproductive output than plants germinating in late spring. Lowered population growth for 1997 is attributed to a cooler and dryer than average early spring that delayed germination and subsequent seed production. Elasticity analysis also suggested that the presence of a persistent seed bank was crucial for long‐term population maintenance and may allow for recovery in areas of low aboveground abundance through soil manipulation.     

Adult stature and age at menarche in Zapotec-speaking communities in the Valley of Oaxaca,Mexico, in a secular perspective

Adult stature and the age at menarche among individuals from Zapotec-speaking communities in the Valley of Oaxaca in southern Mexico are considered in a secular perspective. Four sets of observations are utilized: (1) adult stature in males and females from five rural communities; (2) age at menarche in adult women and school girls from a single rural community; (3) earlier studies of adult stature in the Valley of Oaxaca; and (4) estimated stature from long bones excavated in various archaeological sites in the Valley of Oaxaca. There were no significant differences among the five communities for stature; hence, the data were pooled for analysis and comparison. Results of linear regression of stature and stature adjusted for the estimated effects of aging after 30 years of age on year of birth indicate negligible secular changes in either sex. Comparisons with statures from earlier surveys, the earliest dates to 1899, also indicate negligible changes. When adult women are grouped according to age, there are no differences in mean ages at menarche between the older and younger women. Mean age at menarche for the total adult sample is 14.53 ± 0.08 years, which compares favorably with the probit estimate for school girls, 14.70 ± 0.32 years. These results thus suggest virtually no secular change in adult size and maturity of the Zapotec-speaking population in the Valley of Oaxaca over the past 80 years. Differences in stature between contemporary populations and estimated statures from long bones from several archaeological sites in Oaxaca are small, and thus suggests little secular change over the past one to two–thousand years.     

Demographic and Landscape Change in the Lake Pátzcuaro Basin, Mexico: Abandoning the Garden

Land degradation is frequently cited as a factor in the collapse of ancient complex societies. Implicit in these tales of ecological suicide is the assumption that land degradation is an ecological rather than a social problem. Here, I discuss how land degradation can be reconceptualized as a social–environmental dialectic. I then discuss the implications of this perspective using evidence from a recent landscape project exploring diachronic relationships between environmental and social transformations in the development of the Precolumbian Tarascan (Purépecha) empire, centered in the Lake Pátzcuaro Basin, Mexico. Project findings challenge common conceptions regarding the impact of agriculture, urbanism, and state collapse on ancient landscapes, as well as the dating of the most serious episodes of degradation.