Historical Ecology - Landscapes in Historical Ecology

Landscapes in Historical Ecology

In historical ecology, the landscape is defined as an area of interaction between human culture and the non-human environment. The landscape is a perpetually changing, physical manifestation of history. Historical ecology revises the notion of the ecosystem and replaces it with the landscape. While an ecosystem is static and cyclic, a landscape is historical. While the ecosystem concept views the environment as always trying to return to a state of equilibrium, the landscape concept considers "landscape transformation" to be a process of evolution. Landscapes do not return to a state of equilibrium, but are palimpsests of successive disturbances over time. The use of "landscape" instead of "ecosystem" as the core unit of analysis lies at the heart of historical ecology.

Various individuals and schools of thought have informed the idea of the landscape as historical ecologists conceive of it. The Old English words landskift, landscipe or landscaef refer to environments that have been altered by humans. As this etymology demonstrates, landscapes have been conceived of as related to human culture since at least the 5th century CE. Cultural and historical geographers have had a more recent influence. They adopted this idea from nineteenth-century German architects, gardeners, and landscape painters in Europe, Australia, and North America. Landscapes are not only physical objects, but also "forms of knowledge". Landscapes have cultural meanings, for example, the sacredness in many cultures of burial grounds. This recognition of landscapes as forms of knowledge is central to historical ecology, which studies landscapes from an anthropocentric perspective.

The idea of the cultural landscape is directly attributed to American geographer Carl Sauer. Sauer's theories developed as a critique of environmental determinism, which was a popular theory in the early twentieth century. Sauer's pioneering 1925 paper "The Morphology of Landscape" is now fundamental to many disciplines and defines the domain. In this, the term landscape is used in a geographical sense to mean an arbitrarily selected section of reality; morphology means the conceptual and methodological processes for altering it. Hence to Sauer, wherever humans lived and impacted the environment, landscapes with determinate histories resulted.

The perception of the landscape in historical ecology differs from other disciplines, such as landscape ecology. Landscape ecologists often attribute the depletion of biodiversity to human disturbance. Historical ecologists recognize that this is not always true. These changes are due to multiple factors that contribute to the ever-changing landscape. Landscape ecology still focuses on areas defined as ecosystems. In this, the ecosystem perpetually returns to a state of equilibrium. In contrast, historical ecologists view the landscape as perpetually changing. Landscape ecologists view noncyclical human events and natural disasters as external influences, while historical ecologists view disturbances as an integral part of the landscape's history. It is this integration of the concept of disturbance and history that allows for landscape to viewed as palimpsests, representing successive layers of change, rather than as static entities.

Historical ecologists recognize that landscapes undergo continuous alteration over time and these modifications are part of that landscape's history. Historical ecology recognizes that there is a primary and a secondary succession that occurs in the landscape. These successions should be understood without a preconceived bias against humanity. Landscape transformations are ecological successions driven by human impacts. Primary landscape transformations occur when human activity results in a complete turnover of species and major substrate modifications in certain habitats while secondary landscape transformations involve human-induced changes in species proportions. The stages of landscape transformation demonstrate the history of a landscape. These stages can be brought on by humans or natural causes. 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. Such landscape transformation does not inherently reduce biodiversity or harm the environment. There are many cases in which human-mediated disturbance increases biodiversity as landscapes transform over time.

Historical ecology challenges the very notion of a pristine landscape, such as virgin rainforests. The idea that the landscape of the New World was uninhabited and unchanged by those groups that did inhabit it was fundamental to the justifications of colonialism. Thus, perceptions of landscape have profound consequences on the histories of societies and their interactions with the environment. All landscapes have been altered by various organisms and mechanisms prior to human existence on Earth. Humans have always transformed the landscapes they inhabit, however, and today there are no landscapes on Earth that have not been affected by humans in some way.

Human alterations have occurred in different phases, including the period prior to industrialization. These changes have been studied through the archeological record of modern humans and their history. The evidence that classless societies, like foragers and trekkers, were able to change a landscape was a breakthrough in historical ecology and anthropology as a whole. Using an approach that combines history, ecology, and anthropology, a landscape's history can be observed and deduced through the traces of the various mechanisms that have altered it, anthropogenic or otherwise. Understanding the unique nature of every landscape, in addition to relations among landscapes, and the forms which comprise the landscape, is key to understanding historical ecology.