Deborah L. Nichols
The Basin of Mexico is a key world region for understanding agricultural intensification and the development of ancient and historic cities and states. Archaeologists working in the region have had a long-standing interest in understanding the dynamics of interactions between society and environment and their research has been at the forefront of advances in both method and theory. The Basin of Mexico was the geopolitical core of the Aztec empire, the largest state in the history of Mesoamerica. Its growth was sustained by a complex economy that has been the subject of much research.
Two themes underlie a broad interest in the pre-Hispanic agriculture of the Basin of Mexico. First, how with a Neolithic technology did the Aztecs and their predecessors sustain the growth of large cites, dense rural populations, and the largest state system in the history of pre-Hispanic Mesoamerica? Second, what is the relationship of agricultural intensification and urbanization and state formation? Mesoamerica is the only world region where primary civilizations developed that lacked domestic herbivores for either food or transportation. Their farming depended entirely on human labor and hand tools but sustained large cities, dense populations, and complex social institutions. Intensive agriculture began early and was promoted by risk, ecological diversity, and social differentiation, and included irrigation, terracing, and drained fields (chinampas). Most farming was managed by smallholder households and local communities, which encouraged corporate forms of governance and collective action. Environmental impacts included erosion and deposition, but were limited compared with the degradation that took place in the colonial period.
Aijun Ding, Xin Huang, and Congbin Fu
Air pollution is one of the grand environmental challenges in developing countries, especially those with high population density like China. High concentrations of primary and secondary trace gases and particulate matter (PM) are frequently observed in the industrialized and urbanized regions, causing negative effects on the health of humans, plants, and the ecosystem.
Meteorological conditions are among the most important factors influencing day-to-day air quality. Synoptic weather and boundary layer dynamics control the dispersion capacity and transport of air pollutants, while the main meteorological parameters, such as air temperature, radiation, and relative humidity, influence the chemical transformation of secondary air pollutants at the same time. Intense air pollution, especially high concentration of radiatively important aerosols, can substantially influence meteorological parameters, boundary layer dynamics, synoptic weather, and even regional climate through their strong radiative effects.
As one of the main monsoon regions, with the most intense human activities in the world, East Asia is a region experiencing complex air pollution, with sources from anthropogenic fossil fuel combustion, biomass burning, dust storms, and biogenic emissions. A mixture of these different plumes can cause substantial two-way interactions and feedbacks in the formation of air pollutants under various weather conditions. Improving the understanding of such interactions needs more field measurements using integrated multiprocess measurement platforms, as well as more efforts in developing numerical models, especially for those with online coupled processes. All these efforts are very important for policymaking from the perspectives of environmental protection and mitigation of climate change.
Simon Holdaway and Rebecca Phillipps
Northeast Africa forms an interesting case study for investigating the relationship between changes in environment and agriculture. Major climatic changes in the early Holocene led to dramatic changes in the environment of the eastern Sahara and to the habitation of previously uninhabitable regions. Research programs in the eastern Sahara have uncovered a wealth of archaeological evidence for sustained occupation during the African Humid Period, from about 11,000 years ago. Initial studies of faunal remains seemed to indicate early shifts in economic practice toward cattle pastoralism. Although this interpretation was much debated when it was first proposed, the possibility of early pastoralism stimulated discussion concerning the relationships between people and animals in particular environmental contexts, and ultimately led to questions concerning the role of agriculture imported from elsewhere in contrast to local developments. Did agriculture, or indeed cultivation and domestication more generally (sensu Fuller & Hildebrand, 2013), develop in North Africa, or were the concepts and species imported from Southwest Asia? And if agriculture did spread from elsewhere, were just the plants and animals involved, or was the shift part of a full socioeconomic suite that included new subsistence strategies, settlement patterns, technologies, and an agricultural “culture”? And finally, was this shift, wherever and however it originated, related to changes in the environment during the early to mid-Holocene?
These questions refer to the “big ideas” that archaeologists explore, but before answers can be formed it is important to consider the nature of the material evidence on which they are based. Archaeologists must consider not only what they discover but also what might be missing. Materials from the past are preserved only in certain places, and of course some materials can be preserved better than others. In addition, people left behind the material remains of their activities, but in doing so they did not intend these remains to be an accurate historical record of their actions. Archaeologists need to consider how the remains found in one place may inform us about a range of activities that occurred elsewhere for which the evidence may be less abundant or missing. This is particularly true for Northeast Africa where environmental shifts and consequent changes in resource abundance often resulted in considerable mobility. This article considers the origins of agriculture in the region covering modern-day Egypt and Sudan, paying particular attention to the nature of the evidence from which inferences about past socioeconomies may be drawn.
Maria Cristina Fossi and Cristina Panti
A vigorous effort to identify and study sentinel species of marine ecosystem in the world’s oceans has developed over the past 50 years. The One Health concept recognizes that the health of humans is connected to the health of animals and the environment. Species ranging from invertebrate to large marine vertebrates have acted as “sentinels” of the exposure to environmental stressors and health impacts on the environment that may also affect human health. Sentinel species can signal warnings, at different levels, about the potential impacts on a specific ecosystem. These warnings can help manage the abiotic and anthropogenic stressors (e.g., climate change, chemical and microbial pollutants, marine litter) affecting ecosystems, biota, and human health.
The effects of exposure to multiple stressors, including pollutants, in the marine environment may be seen at multiple trophic levels of the ecosystem. Attention has focused on the large marine vertebrates, for several reasons. In the past, the use of large marine vertebrates in monitoring and assessing the marine ecosystem has been criticized. The fact that these species are pelagic and highly mobile has led to the suggestion that they are not useful indicators or sentinel species. In recent years, however, an alternative view has emerged: when we have a sufficient understanding of differences in species distribution and behavior in space and time, these species can be extremely valuable sentinels of environmental quality.
Knowledge of the status of large vertebrate populations is crucial for understanding the health of the ecosystem and instigating mitigation measures for the conservation of large vertebrates. For example, it is well known that the various cetacean species exhibit different home ranges and occupy different habitats. This knowledge can be used in “hot spot” areas, such as the Mediterranean Basin, where different species can serve as sentinels of marine environmental quality. Organisms that have relatively long life spans (such as cetaceans) allow for the study of chronic diseases, including reproductive alterations, abnormalities in growth and development, and cancer. As apex predators, marine mammals feed at or near the top of the food chain. As the result of biomagnification, the levels of anthropogenic contaminants found in the tissues of top predators and long-living species are typically high. Finally, the application of consistent examination procedures and biochemical, immunological, and microbiological techniques, combined with pathological examination and behavioral analysis, has led to the development of health assessment methods at the individual and population levels in wild marine mammals. With these tools in hand, investigators have begun to explore and understand the relationships between exposures to environmental stressors and a range of disease end points in sentinel species (ranging from invertebrates to marine mammals) as an indicator of ecosystem health and a harbinger of human health and well-being.