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“Muck and the ancient Maya: Wetland geomorphology and paleoecology near Akab Muclil, Rio Bravo floodplain of the Belize coastal plain” Accepted by Geomorphology

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Abstract

To understand wetland geomorphology and paleoecology, we collected a 2.6 m sediment core from a flooded swamp adjacent to the Maya archaeological site of Akab Muclil in the Maya Lowlands of northwestern Belize. The site of Akab Muclil has a known occupation that persisted from Early Classic (1700–1350 years BP) through the Terminal Maya Classic (1180-1050 BP) and into the Postclassic (1050-450 BP) and lies near a vast network of ancient Maya canal and field systems. We analyzed this core using a combination of paleoecological and geochemical techniques to determine the history of land use and natural change over time within this wetland. AMS dating, pollen, charcoal analysis, micropaleontology, geochemical analysis, and magnetic susceptibility provide a suite of methods from which we interpret the geomorphic and ecological history of this wetland system. Four AMS dates from the length of the core provide us with an age model that runs from 1675 cal years BP through the Maya Classic onward to the present. At the base of this system, soil composition and chemistry provide evidence that the system changed from a seasonally wet terrestrial soil to a perennially wet swamp, since the basal Mollisol soil lies buried by peats and calcareous sediments. This shift to the perennial wetland could be related to ancient Maya water management or a natural geomorphic change, though we suspect the former because of the nearby ancient Maya large-scale geomorphic and hydrological manipulation in the form of intensive canalization and agriculture. Evidence of ancient Maya uses and impacts, including sedimentation, Zea mays pollen, and high charcoal counts occur from the lowest levels of the sequence through the Classic and into the Postclassic period. Above this level, the strata change to stable peats, laminated deposits of light gray/dark gray gypsum, authigenic carbonate, and layers of fibrist peat, with little evidence of human impact until recent increases in charcoal and phosphorous. This study, compared with other regional studies, indicates a later transition from terrestrial to wetland, later human impacts in the Postclassic, and a geomorphic impact record closely tied to the history of the adjacent site rather than broader land use trends.

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Tropical wetlands assume important functions in the landscape and contribute considerably to the welfare of large parts of the human population, but they are seriously threatened because they are considered free resources of land and water. This review summarizes long-term environmental trends for tropical wetlands and predicts their future to the time horizon 2025. Many tropical countries do not have the economic strength, scientific and technological capacity, and/or administrative infrastructure to adequately react to the challenges of increasing population pressure and globalization of the economy with respect to the sustainable use of the resources. Furthermore, political instability and armed conflicts affect large areas in several tropical countries, hindering wetland research and management. Detailed wetland inventories are missing in most countries, as are plans for a sustainable management of wetlands in the context of a long-term integrated watershed management. Despite large regional variability, a continental ranking shows, in decreasing order of wetland integrity, South America, Africa, Australia and Asia, while efforts to mitigate human impacts on wetlands are largest and most advanced in Australia. Analysis of demographic, political, economic and ecological trends indicates fairly stable conditions for wetlands in tropical Australia, slight deterioration of the large wetland areas in tropical South America excepting the Magdalena and Cauca River flood plains where human population is larger, rapidly increasing pressure and destruction on many African and Central American wetlands and serious threats for the remaining wetlands in tropical Asia, by the year of 2025. Policy deficiencies, deficient planning concepts, limited information and awareness and institutional weakness are the main administrative reasons for wetland degradation and must be overcome to improve wetland management and protection in future. Intensification of international cooperation and assistance is considered of fundamental importance for most tropical countries to solve problems related to wetland research, protection and sustainable management.
Article
Wetland research in northern Belize provides the earliest evidence for development of agriculture in the Maya Lowlands. Pollen data confirm the introduction of maize and manioc before 3000 B.C. Dramatic deforestation, beginning ca. 2500 B.C. and intensifying in wetland environments ca. 1500-1300 B.C., marks an expansion of agriculture, which occurred in the context of a mixed foraging economy. By 1000 B.C. a rise in groundwater levels led farmers to construct drainage ditches coeval with the emergence of Maya complex society ca. 1000-400 B.C. Field manipulations often involved minor modifications of natural hummocks. Canal systems are not as extensive in northern Belize as previously reported, nor is there evidence of artificially raised planting platforms. By the Classic period, wetland fields were flooded and mostly abandoned.
Article
Prehistoric ridged fields and canals were recognized from the air in 1968 along the Candelaria River of Campeche, Mexico, in the vicinity of sites described by E. Willys Andrews in 1943. These remains were subsequently identified by Scholes and Roys as the settlements of Acalan, a native province along the route of the journey by Cortes to Honduras. Ground exploration in 1969 and 1970 has suggested that the fields were used over a considerable period of time under a system of diversified horticulture. The extensive canal system apparently provided access from the rivers to firm ground and allowed shortcuts and bypasses alongside the rivers themselves. The landscape suggests a considerable prehistoric population, vigorously engaged in major public works projects over a large area. It invites further integrated investigation of its past human ecology, particularly for information on variants of basic Lowland Maya subsistence patterns and the new perspectives this may give on the structure, success and demise of this civilization. An earlier version of this paper was read at the 39th International Congress of Americanists in Lima, 1970.
Article
Market economies ore notoriously difficult to identify in the archeological record. This is particularly true in the subtropical Maya lowlands of Mexico, Guatemala, and Belize because most utilitarian items and consumables were made of highly perishable materials. We explore the hypothesis that ancient marketplaces can be identified through analysis of chemical residues in soils from open and easily accessible spaces in and about ancient Maya cities. We compared soil chemical signatures from a credible ancient marketplace location in the specialized trade center of Chunchucmil, Yucatan, Mexico to those from a modern marketplace at Antigua, Guatemala. We found extraordinarily high concentrations of phosphorus and zinc in the soil of Chunchucmil's proposed marketplace and the same high concentrations correlate well with food preparation and vegetable sales areas at the modern marketplace. These methods hold promise in resolving the vexing question of how large ancient Maya urban populations were sustained.
Article
One of the most distinctive features of the Postclassic capital of Mayapan is the immense wall that encloses large portions of the site's settlement zone. This 9.1 km-long feature is the largest example of a walled enclosure known in Mesoamerica. Based on ethnohistoric references, it seems that the construction was well known to Postclassic and Colonial period residents of the Northern lowlands. The most common assertion regarding the enclosures is that the wall had primarily defensive functions. Unfortunately, little solid archaeological evidence or cross-cultural comparison has been offered to support this interpretation. In this paper, I correlate the form of the gates with cross-culturally derived and unambiguously defensive features, finding that the design of the gates strongly suggests that they are indeed defensive. Possible secondary functions of the wall are also explored, such as the control of people and goods entering the city, as ritual barrier, the control of internal populations and its symbolism.
Article
Previous interpretations of the occupation history of La Milpa, Belize, which were based on preliminary ceramic data, suggested that occupation of the site fluctuated dramatically from the Late Preclassic to the Terminal Classic (400 b.c.–a.d. 850). It was determined that the modest Late Preclassic village became a large Early Classic city with regal-ritual architecture and carved monuments. In Late Classic I, it appeared the site was nearly abandoned. Its reoccupation and exponential growth in Late Classic II was followed by rapid abandonment before the end of the Late Classic III/Terminal Classic. New ceramic analyses utilizing attribute analysis with an emphasis on formal modes has clarified the sequence and, in turn, softened the occupation curves. This article provides descriptions of the Late Classic I, II, and III ceramics, along with revised percentage frequency graphs of La Milpa's occupation history based primarily on the work of the La Milpa Archaeological Project (1992–2002).
Article
This study evaluates the importance of rejolladas to the Ancient Maya in and around the Classic Maya center of Xuenkal, Yucatán State, Mexico. Rejolladas are collapse sinkholes with bases above the local water table. We present a spatial and physical analysis of 186 rejolladas in a 10 × 10 km area centered on Xuenkal. Basal diameters range from ∼22 to 264 m, areas range from 0.04 to 5.48 ha, and depths range from 4 to 12 m. Spatial density ranges from 0 to 8 rejolladas/km2 with higher densities coinciding with known Ancient Maya settlements. Within Xuenkal, residential groups tend to be organized around and focused on the rejolladas. Some rejolladas have modified slopes that may be remnants of terraces or entry paths. High-resolution satellite imagery analysis demonstrates that rejolladas have denser and healthier vegetation than the surrounding landscape especially in the dry season. Microclimate data demonstrate that the bottom of rejolladas has less extreme diurnal temperature ranges, lower daytime highs, higher atmospheric moisture, and significantly higher and more stable soil moisture. Based on the archaeology at Xuenkal, it appears that the Ancient Maya recognized and actively exploited these environmental microniches for intensive cultivation both locally and regionally.
Article
An annually laminated stalagmite from the northern Yucatán peninsula contains mud layers from 256 cave flooding events over 2,240 years. This new conservative proxy for paleotempestology recorded cave flooding events with a recurrence interval of 8.3 years during the 20th century, with the greatest frequency during the 20th century and the least frequent during the 17th century. Tropical cyclone (TC) events are unlikely to flood the cave during drought when the water table is depressed. Applying TC masking [Frappier, 2013] to the Chaac paleorainfall reconstruction [Medina-Elizalde and Rohling, 2012] suggests that the severity of the Maya 'megadroughts' was underestimated. Without a high-resolution radiometric geochronology of individual local TC events, speleothem isotope records cannot resolve whether the Terminal Classic Period in the northern Maya Lowlands was punctuated by several brief drought breaks with normal TCs, or whether the region was very dry and peppered by unusually severe and frequent hurricane seasons.
Article
Agriculture arose during a period of profound global climatic and ecological change following the end of the Pleistocene. Yet, the role of phenotypic plasticity – an organism's ability to change its phenotype in response to the environment – and environmental influences in the dramatic phenotypic transformations that occurred during plant domestication are poorly understood. Another factor possibly influential in agricultural origins, the productivity of crop plant wild progenitors in Late Pleistocene vs. Holocene environments, has received increasing attention recently and merits further investigation. In this study, we examined phenotypic characteristics and productivity (biomass, seed yield) in the wild progenitor of maize, the teosinte Zea mays ssp. parviglumis H.H. Iltis & Doebley, when it was first exploited and cultivated by growing it in atmospheric CO2 concentrations and temperatures characteristic of the late-glacial and early Holocene periods. Plants responded with a number of attributes uncharacteristic of teosinte in today's environments, including maize-type traits in vegetative architecture, inflorescence sexuality, and seed maturation. Teosinte productivity was significantly lower in late-glacial compared with early Holocene and modern environments. Our evidence indicates that: a) ancestral biological characteristics of crop plant progenitors aren't always predicted from living examples, b) some important maize phenotypic traits were present at initial human exploitation and selection, and c) Pleistocene plant productivity should be considered a significant factor in the chronology of food production origins.
Article
The New World tropical forest is now considered to be an early and independent cradle of agriculture. As in other areas of the world, our understanding of this issue has been significantly advanced by a steady stream of archaeobotanical, paleoecological, and molecular/genetic data. Also importantly, a renewed focus on formulating testable theories and explanations for the transition from foraging to food production has led to applications from subdisciplines of ecology, economy, and evolution not previously applied to agricultural origins. Most recently, the integration of formerly separated disciplines, such as developmental and evolutionary biology, is causing reconsiderations of how novel phenotypes, including domesticated species, originate and the influence of artificial selection on the domestication process. It is becoming clear that the more interesting question may be the origins of plant cultivation rather than the origins of agriculture. This paper reviews this body of evidence and assesses current views about how and why domestication and plant food production arose.