Habitat diversity: landscapes and ecosystems

LANDSCAPE DIVERSITY: Humanity's imprint on nature

Landscapes are made up of sets of natural and cultural elements which have been shaped by human's imprint. In western and central Europe there is almost no virgin landscape left. By developing agriculture human beings have generated coppice forests. Certain landscapes are totally artificial, for example, the Minsmere nature reserve in England and, to a certain extent, the Poitou marshland and the Landes forest in France.

The concept of landscape diversity takes account of the relationships between landscapes:

their territorial organisation, dynamics and inter-relationships as seen by individuals and societies through different local, regional and national cultures.
Landscapes, in all their quality and diversity, are fashioned by human activities undertaken over thousands of years. They are continually evolving, owing to the constant changes in the way that different societies use land. Landscapes consequently embody the collective memory of nature and their inhabitants, forming a complex element of the environment.

ECOSYSTEM DIVERSITY: environments in constant evolution

An ecosystem is made up of a community of organisms, their environment and the interactions between them. Ecosystems are formed on very different scales, ranging from microsites to the biosphere. A forest constitutes an ecosystem, as does a dead tree-trunk, a river, a pond, a mountain, a sea and even the entire planet.

An ecosystem is a dynamic unit in which the composition, structure and roles of the different elements with-in it are constantly evolving with time.

It is difficult to assess the precise role of biodiversity in the complexity of ecosystems. We do not know to what extent particular ecosystem features, such as primary production and decomposition, owe their preservation to biodiversity. Nonetheless, it has been observed that certain species (known as "dominant" or "key" species) have a major influence on ecosystem structures and functions.