Environmental and Ecological Archaeology

Environmental and ecological archaeology is the study of the relationship between past human populations and their environments. Rather than study human artifacts themselves, the tools, pottery, buildings etc. that other archaeologists concern themselves with, environmental and ecological archaeologists study the geological and biotic environment and components of archaeological settlements and sites. There are three main subfields - geoarchaeology, archaeobotany (sometimes called paleobotany or even paleoethno-botany), and zooarchaeology (sometimes called archae-zoology). Geoarchaeology is the study of the geology of archaeological settlements and sites. Archaeobotany is the study of plant remains and zooarchaeology of animal remains from archaeological sites.

Geoarchaeology

The geoarchaeology of a settlement or site includes the nature of the underlying bedrock; ‘drift’ deposits from ice sheets, rivers, and ancient lakes; and ‘land-forms’ of sediments shaped by subsequent deposition or erosion. (The term ‘geomorphology’, literally the shape of the landscape, is sometimes used to apply to all three and, sometimes, only to the latter.) Geology in general, and landforms in particular, are important because they affect things such as water supplies, potential communication routes, defensibility, and agricultural potential. They are particularly important in the study of paleolithic sites because landforms may well have been changed by natural processes since they were inhabited, affecting interpretations of other data. In addition, human activity itself, particularly intensive agriculture, alters the landscape. Hence, understanding landscapes and the changes they have undergone through time are critically important in understanding archaeological sites. Mapping, including remote sensing techniques, are important in geoarchaeology. The study of sediments and surface soils is also as important. Many physical and chemical properties of sediments and soils have been studied, normally away from the field in laboratories, or in experiments replicating ancient conditions and practices, both of which have resulted in significant information about the origin, preservation, and destruction of archaeological sites.

Archaeobotany and Zooarchaeology

Plant and animal remains from archaeological sites and settlements are particularly informative. They can be used to distinguish the type of biome present - tropical forest, temperate deciduous forest, temperate coniferous forest, grasslands, desert, tundra, and mountains - some of which may have changed over the time of human occupation. Plant remains including nut shells, fruit stones, grains, and seeds can be informative about mode of subsistence, land use, diet, and changes in these. Particularly well developed is the study of pollen and spores. These are often well preserved because they were naturally selected to disperse and be resistant to various kinds of stress. They are usually separated from soil samples by flotation and studied under microscopes and even their DNA is sometimes analyzed. This permits identification down to the species level and, in some cases, can show changes in species through time, reflecting climate change or selective breeding. Similarly, animal remains can be informative about the biome as well as about fishing and the hunting and domestication of animals. Again, certain parts are more likely than others to be preserved, for instance, shells, insect exoskeletons, and the bones of fish and small and large mammals.

One ‘micro’ example of the success of environmental and ecological archaeology involves a ‘farm mound’ on Papa Westray, an island in the Orkney archipelago off the northern tip of Scotland. The mound, once thought to result from either a dung heap or a decayed and replaced turf building, was shown by a combination of geoarchaeological, archaeo-botanical, and zooarchaeological methods to be the remains of a twelfth-century fish-processing site. One ‘macro’ example is the light they have shed on the mass extinctions of mega-fauna (large animals) around the world which followed shortly after the arrival of prehistoric humans (see discussion below).

Impact on the Environment

Both cultural anthropologists and archaeologists have normally described the relationship of cultures and past human populations with the environment as an ‘interactive’ one. Practically, however, historically both tended to place more emphasis on the effects of the environment on people rather than the effects of people on the environment. In recent years, though, that has changed. Archaeological research has made it clear that there never was an ‘Eden’ in which people lived in a stable, harmonious balance with their environment. It is also the case that as the scale of human societies increased, as both population sizes and the amount of resources acquired from nature per capita increased from hunting and gathering through horticulture and pastoralism through intensive agriculture, the ‘footprint’ left on the Earth has increased. This has, of course, reached its apogee in industrial societies in which human and animal labor has largely been replaced by machines using fossil fuels, the type of society not commonly studied by archaeologists. Resource depletion and environmental degradation have been ubiquitous, but generally increasing in human history.

Archaeological evidence for the impact of humans on the environment comes from a great many parts of the world, time periods, modes of subsistence, and social organization. They include the massive extinction of birds by Polynesian colonizers; deforestation of the Maya lowlands; the salinization of lands in southern Mesopotamia; social erosion in ancient Greece; the deforestation and elimination of virtually all bird fauna on Easter Island; and the extinction of mega-fauna at the end of the last ice age after upper Paleolithic hunters of Siberia crossed the Bering Straits to the Americas. In the latter case, climate change may have played a role, but so did humans in the extinction of mammoths, mastodons, ground sloths, horses, and camels. There are now available archaeological landscape histories of all of the major civilizations, including Egypt, Mesopotamia, the Indus valley, China, Mesoamerica, and the Andean region of South America. Most reveal resource depletion and environmental degradation resulting from interactions between climate change and landscape changes resulting from human activities, particularly deforestation, overgrazing, and salinity from irrigation. In more recent history, the devastation has spread from terrestrial to freshwater and marine ecosystems.