Historical ecology

Historical ecologists recognize that humans have had world-wide influences, impact landscape in dissimilar ways which increase or decrease species diversity, and that a holistic perspective is critical to be able to understand that system.

[3] Piecing together landscapes requires a sometimes difficult union between natural and social sciences, close attention to geographic and temporal scales, a knowledge of the range of human ecological complexity, and the presentation of findings in a way that is useful to researchers in many fields.

For example, Deevey used radiocarbon dating to reconcile biologists’ successions of plants and animals with the sequences of material culture and sites discovered by archaeologists.

The papers highlighted the importance of understanding social and political structures, personal identities, perceptions of nature, and the multiplicity of solutions for environmental problems.

Deevey's Historical Ecology of the Maya Project (1973-1984) was carried out by archaeologists and biologists who combined data from lake sediments, settlement patterns, and material from excavations in the central Petén District of Guatemala to refute the hypotheses that a collapse of Mayan urban areas was instigated by faltering food production.

[10] Carole L. Crumley's Burgundian Landscape Project (1974–present) is carried out by a multidisciplinary research team aimed at identifying the multiple factors which have contributed to the long-term durability of the agricultural economy of Burgundy, France.

[11] Thomas H. McGovern's Inuit-Norse Project (1976–present) uses archaeology, environmental reconstruction, and textual analysis to examine the changing ecology of Nordic colonizers and indigenous peoples in Greenland, Iceland, Faeroes, and Shetland.

[13] Florida Keys Coral Reef Eco-region Project (1990–present) researchers at the Scripps Institute of Oceanography are examining archival records including natural history descriptions, maps and charts, family and personal papers, and state and colonial records in order to understand the impact of over-fishing and habitat loss in the Florida Keys, USA which contains the third largest coral reef in the world.

A later approach was the historical viewpoint of Franz Boas which refuted environmental determinism, claiming that it is not nature, but specifics of history, that shape human cultures.

These revisions and related critiques of environmental anthropology undertook to take into account the temporal and spatial dimensions of history and cultures, rather than continuing to view populations as static.

Thus, historical ecology as a research program developed to allow for the examination of all types of societies, simple or complex, and their interactions with the environment over space and time.

It is this integration of the concept of disturbance and history that allows for landscape to be viewed as palimpsests, representing successive layers of change, rather than as static entities.

[16] Parts of the Amazon rainforest exhibit different stages of landscape transformation such as the impact of indigenous slash-and-burn horticulture on plant species compositions.

Today, in the absence of indigenous populations who once practiced controlled burns (most notably in North America and Australia), naturally ignited wildfires have increased.

[16] At present, fertilization yields larger, more productive harvests of crops, but also has had adverse effects on many landscapes, such as decreasing the diversity of plant species and adding pollutants to soils.

Biological invasions are composed of exotic biota that enter a landscape and replace species with which they share similarities in structure and ecological function.

Because they multiply and grow quickly, invasive species can eliminate or greatly reduce existing flora and fauna by various mechanisms, such as direct competitive exclusion.

[16] Humans have on their migrations through the ages taken along plants of agricultural and medicinal value, so that the modern distribution of such favored species is a clear mapping of the routes they have traveled and the places they have settled.

For instance, Bushmen and Australian Aborigines have half as many intestinal parasites as African and Malaysian hunter-gatherers living in a species-rich tropical rainforest.

[32] Pre-Columbian, indigenous agriculturalists developed capabilities with which to raise crops under a wide range of ecological conditions, giving rise to a multiplicity of altered, cultivated landscapes.

Clark Erickson observes that pre-Hispanic savanna peoples of the Bolivian Amazon built an anthropogenic landscape through the construction of raised fields, large settlement mounds, and earthen causeways.

Transformation continues in more recent times as noted when in 1961, a group of villagers from Igarapé Guariba cut a canal about two miles (3 km) long across fields thick with tall papyrus grass and into dense tropical rain forest.

The narrow canal and the stream that flowed into it have since formed a full-fledged river more than six hundred yards wide at its mouth, and the landscape in this part of the northern Brazilian state of Amapá was dramatically transformed.

Consistent with the basic premises of historical ecology, it is recognized that anthropogenic soil management practices can have both positive and negative effects on local biodiversity.

The iconic mounds of the Hopewell Indians built in the Ohio River valley likely served a religious or ceremonial purpose, and show little evidence of changing soil fertility in the landscape.

Terra preta is characterized by the presence of charcoal in high concentrations, along with pottery shards and organic residues from plants, animal bones, and feces.

Studying past relationships between humans and landscapes can successfully aid land managers by helping develop holistic, environmentally rational, and historically accurate plans of action.

Farmers in the Amazon region, for example, now utilize nutrient-rich terra preta to increase crop yields[44] much like the indigenous societies that lived long before them.

The San Francisco Estuary Institute also uses historical ecology to study human impacts on the California landscape to guide environmental management.

By using historical data such as maps, charts, and aerial photographs, researchers were able to trace habitat change to built structures that had negatively altered the tidal flow into the estuaries dating from the early 1900s.