The access to water and the engineered landscapes accommodating its collection and allocation are pivotal issues for assessing sustainability. Recent mapping, sediment coring, and formal excavation at Tikal, Guatemala, have markedly expanded our understanding of ancient Maya water and land use. Among the landscape and engineering feats identified are the largest ancient dam identified in the Maya area of Central America; the posited manner by which reservoir waters were released; construction of a cofferdam for dredging the largest reservoir at Tikal; the presence of ancient springs linked to the initial colonization of Tikal; the use of sand filtration to cleanse water entering reservoirs; a switching station that facilitated seasonal filling and release; and the deepest rock-cut canal segment in the Maya Lowlands. These engineering achievements were integrated into a system that sustained the urban complex through deep time, and they have implications for sustainable construction and use of water management systems in tropical forest settings worldwide.archaeology | resilience | intensification | tropics | paleoecology H ow human populations have used currently threatened environments in a sustainable and managed manner over time can be addressed through archeology and its multidisciplinary collaborations (1). Today, in the geographical core of Classic Maya civilization (A.D. 250-800)-the tropical forest of Petén, Guatemala (a subtropical moist forest in the Holdridge system) (2)-short-fallow slash-and-burn agriculture, logging, and cattle ranching have significantly affected portions of the ecosystem and limited access to potable water (3, 4). Nevertheless, within this biophysical context, one of the earliest and most long-lived tropical civilizations flourished. Maya water and land uses were significantly affected by highly seasonal precipitation and karst physiography, which accommodated little perennial surface water. In response, the ancient Maya developed a complex system of water management dependent on water collection and storage devices. The hydraulic system was cleverly tailored to the biophysical conditions and adaptively engineered to the evolving needs of a growing population for more than 1,000 y (5-7). By identifying how a tropical setting was altered using a Stone Age technology, methods and techniques associated with long-lived and sustainable landscape engineering are revealed. Establishing baseline assessments of human impact on an environment before the extraction and depletion of resources by recent technological advancements may allow an evaluation of current technology's effects and the origins of unintended ecological as well as social consequences.The ancient low-density urban community of Tikal, Guatemala, was recently examined by way of water and landscape assessments (8-10).* Our intent was to document the evolution of a tropical wet-dry engineered landscape (11) and the manner in which the site was altered from its initial colonization (Middle to Late Preclassic, 600 B.C. to A.D. ...

a b s t r a c tThe measure of the "Mayacene," a microcosm of the Early Anthropocene that occurred from c. 3000 to 1000 BP, comes from multiple Late Quaternary paleoenvironmental records. We synthesized the evidence for Maya impacts on climate, vegetation, hydrology and the lithosphere, from studies of soils, lakes, floodplains, wetlands and other ecosystems. Maya civilization had likely altered local to regional ecosystems and hydrology by the Preclassic Period (3000-1700 BP), but these impacts waned by 1000 BP. They altered ecosystems with vast urban and rural infrastructure that included thousands of reservoirs, wetland fields and canals, terraces, field ridges, and temples. Although there is abundant evidence that indicates the Maya altered their forests, even at the large urban complex of Tikal as much as 40% of the forest remained intact through the Classic period. Existing forests are still influenced by ancient Maya forest gardening, particularly by the large expanses of ancient stone structures, terraces, and wetland fields that form their substrates. A few studies suggest deforestation and other land uses probably also warmed and dried regional climate by the Classic Period (1700-1100 BP). A much larger body of research documents the Maya impacts on hydrology, in the form of dams, reservoirs, canals, eroded soils and urban design for runoff. Another metric of the "Mayacene" are paleosols, which contain chemical evidence for human occupation, revealed by high phosphorus concentrations and carbon isotope ratios of C 4 species like maize in the C 3 edominated tropical forest ecosystem. Paleosol sequences exhibit "Maya Clays," a facies that reflects a glut of rapidly eroded sediments that overlie pre-Maya paleosols. This stratigraphy is conspicuous in many dated soil profiles and marks the large-scale Maya transformation of the landscape in the Preclassic and Classic periods. Some of these also have increased phosphorous and carbon isotope evidence of C 4 species. We synthesize and provide new evidence of Maya-period soil strata that show elevated carbon isotope ratios (d 13 C), indicating the presence of C 4 species in typical agricultural sites. This is often the case in ancient Maya wetland systems, which also have abundant evidence for the presence of several other economic plant species. The "Mayacene" of c. 3000 to 1000 BP was thus a patchwork of cities, villages, roads, urban heat islands, intensive and extensive farmsteads, forests and orchards. Today, forests and wetlands cover much of the Maya area but like so many places, these are now under the onslaught of the deforestation, draining, and plowing of the present Anthropocene.

The Maya archaeological site at Colha in northern Belize, Central America, has yielded several spouted ceramic vessels that contain residues from the preparation of food and beverages. Here we analyse dry residue samples by using high-performance liquid chromatography coupled to atmospheric-pressure chemical-ionization mass spectrometry, and show that chocolate (Theobroma cacao) was consumed by the Preclassic Maya as early as 600 bc, pushing back the earliest chemical evidence of cacao use by some 1,000 years. Our application of this new and highly sensitive analytical technique could be extended to the identification of other ancient foods and beverages.

We report on a large area of ancient Maya wetland field systems in Belize, Central America, based on airborne lidar survey coupled with multiple proxies and radiocarbon dates that reveal ancient field uses and chronology. The lidar survey indicated four main areas of wetland complexes, including the Birds of Paradise wetland field complex that is five times larger than earlier remote and ground survey had indicated, and revealed a previously unknown wetland field complex that is even larger. The field systems date mainly to the Maya Late and Terminal Classic (∼1,400–1,000 y ago), but with evidence from as early as the Late Preclassic (∼1,800 y ago) and as late as the Early Postclassic (∼900 y ago). Previous study showed that these were polycultural systems that grew typical ancient Maya crops including maize, arrowroot, squash, avocado, and other fruits and harvested fauna. The wetland fields were active at a time of population expansion, landscape alteration, and droughts and could have been adaptations to all of these major shifts in Maya civilization. These wetland-farming systems add to the evidence for early and extensive human impacts on the global tropics. Broader evidence suggests a wide distribution of wetland agroecosystems across the Maya Lowlands and Americas, and we hypothesize the increase of atmospheric carbon dioxide and methane from burning, preparing, and maintaining these field systems contributed to the Early Anthropocene.

Tikal has long been viewed as one of the leading polities of the ancient Maya realm, yet how the city was able to maintain its substantial population in the midst of a tropical forest environment has been a topic of unresolved debate among researchers for decades. We present ecological, paleoethnobotanical, hydraulic, remote sensing, edaphic, and isotopic evidence that reveals how the Late Classic Maya at Tikal practiced intensive forms of agriculture (including irrigation, terrace construction, arboriculture, household gardens, and short fallow swidden) coupled with carefully controlled agroforestry and a complex system of water retention and redistribution. Empirical evidence is presented to demonstrate that this assiduously managed anthropogenic ecosystem of the Classic period Maya was a landscape optimized in a way that provided sustenance to a relatively large population in a preindustrial, low-density urban community. This landscape productivity optimization, however, came with a heavy cost of reduced environmental resiliency and a complete reliance on consistent annual rainfall. Recent speleothem data collected from regional caves showed that persistent episodes of unusually low rainfall were prevalent in the mid-9th century A.D., a time period that coincides strikingly with the abandonment of Tikal and the erection of its last dated monument in A.D. 869. The intensified resource management strategy used at Tikal-already operating at the landscape's carrying capacity-ceased to provide adequate food, fuel, and drinking water for the Late Classic populace in the face of extended periods of drought. As a result, social disorder and abandonment ensued.he Late Classic period (A.D. 600-850) was a time of unprecedented architectural, astronomical, and artistic achievement at Tikal, one of the leading urban centers of the ancient Maya realm. It was also a time of meteoric population growth at this bustling cultural center. Notwithstanding its prominence as a major Maya polity, how Tikal's leaders and farmers managed to provide food, fuel, and other sustenance for its many occupants has never been fully understood or quantified.To best assess resource potential at Tikal, we first defined an extraction zone that was extrapolated from archaeological settlement data by creating a Voronoi diagram (1, 2) (Fig. 1). Essentially, this approach proscribes a proportional boundary between Tikal and its surrounding contemporaneous communities: namely, Motul de San Jose, El Zotz, Uaxactún, Xultun, Dos Aguadas, Nakum, Yaxha, and Ixlu. Using this technique, including assigning greater economic clout to Tikal using a 2:1 weighting scheme (see section on the Voronoi diagram in SI Materials and Methods), we calculated that its Late Classic resource extraction zone encompassed ∼1,100 km 2 . This is the area from which the residents of Tikal could obtain their necessary food, fuel, construction timbers, and other living essentials.Superimposing the Voronoi Diagram over satellite images of modern Tikal (2, 3) (Fig. 1), which is mostly...