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11.1 Introduction: The Notion of Landscape Ecology and the
Management of Coastal Natural Areas
The term Landscape Ecology was first used by a German geographer, Carl Troll
(1939). This researcher in geography, botany, physics and geomorphology was interested in the relationships between the heterogeneity of mountain ecosystems,
phytogeography and human societies. His work was in particular marked by the use
of aerial photography to analyse the heterogeneity of physical environments in relation with the plant cover of mountain environments. If the term was used relatively
early in the history of ecology, it was not until the 1980s that the discipline really
emerged driven by the fledgling I.A.L.E. (International Association for Landscape
Ecology). In contrast to ‘classical’ ecology, which tended to think in terms of populations and communities living in homogeneous ecosystems, landscape ecology is
based on the central notion of spatial and temporal heterogeneity. In the 1980s, the
theoretical concepts of the discipline were mainly based on the analysis of agricultural landscapes where agricultural practices played a major role in the fragmentation
of ecosystems and the functioning of populations.
The founding concepts of the discipline are undoubtedly derived from the theory
of the biogeography of islands developed by McArthur and Wilson (1967), according
to which populations of birds were increasingly isolated and vulnerable in function of
the extent to which the island was small and isolated from other islands. Thus, from
the outset, landscape ecology focused on the relations between the fragmentation of
habitats and the structure of populations or communities. This led Levins (1969) to
develop one of the essential concepts of landscape ecology: that of ‘metapopulation’.
This stipulates that in fragmented habitats, the populations living in each of the
habitats are more or less isolated from each other, according to their capacity to
disperse among each of the habitats separated by other habitats less favourable to
the species. The size of the habitats defines the size of the populations. Each of the
populations can live and be maintained independently of the other populations as
long as its genetic pool is large enough. Below a certain size, the population is in
jeopardy unless it is restocked by neighbouring populations. The small habitats are
thus often occupied by ‘sink populations’, the sustainability of which depends on the
supply of genes from the larger neighbouring populations which then act as ‘source
populations’.
Thus, landscape ecology endeavours to understand the mechanisms, most of them
of anthropic origin, that lead to the structuring of the landscape by acting on the
fragmentation of habitats. These habitats are organised on the basis of a ‘matrix’
(e.g., cultivated fields) or ‘patch’ (e.g. woods) architecture. These relictual forest
ecosystems may be organized in different ways: a continuum of forest and woodlands
interconnected by a bocage network or discontinuously.
The biological connectivity between the forest areas depends on the capacity
for dispersion of organisms and on the structure of the landscape network (shapes,
organization, etc.), the nature of the plots making up the matrix (e.g. size of the
agricultural plots, type of crop) and the distance between the forest habitats. The
study of the biological connectivity is thus a fundamental part of the analytical process
A. Cheminée et al.
11.1 Introduction: The Notion of Landscape Ecology and the
Management of Coastal Natural Areas
The term Landscape Ecology was first used by a German geographer, Carl Troll
(1939). This researcher in geography, botany, physics and geomorphology was interested in the relationships between the heterogeneity of mountain ecosystems,
phytogeography and human societies. His work was in particular marked by the use
of aerial photography to analyse the heterogeneity of physical environments in relation with the plant cover of mountain environments. If the term was used relatively
early in the history of ecology, it was not until the 1980s that the discipline really
emerged driven by the fledgling I.A.L.E. (International Association for Landscape
Ecology). In contrast to ‘classical’ ecology, which tended to think in terms of populations and communities living in homogeneous ecosystems, landscape ecology is
based on the central notion of spatial and temporal heterogeneity. In the 1980s, the
theoretical concepts of the discipline were mainly based on the analysis of agricultural landscapes where agricultural practices played a major role in the fragmentation
of ecosystems and the functioning of populations.
The founding concepts of the discipline are undoubtedly derived from the theory
of the biogeography of islands developed by McArthur and Wilson (1967), according
to which populations of birds were increasingly isolated and vulnerable in function of
the extent to which the island was small and isolated from other islands. Thus, from
the outset, landscape ecology focused on the relations between the fragmentation of
habitats and the structure of populations or communities. This led Levins (1969) to
develop one of the essential concepts of landscape ecology: that of ‘metapopulation’.
This stipulates that in fragmented habitats, the populations living in each of the
habitats are more or less isolated from each other, according to their capacity to
disperse among each of the habitats separated by other habitats less favourable to
the species. The size of the habitats defines the size of the populations. Each of the
populations can live and be maintained independently of the other populations as
long as its genetic pool is large enough. Below a certain size, the population is in
jeopardy unless it is restocked by neighbouring populations. The small habitats are
thus often occupied by ‘sink populations’, the sustainability of which depends on the
supply of genes from the larger neighbouring populations which then act as ‘source
populations’.
Thus, landscape ecology endeavours to understand the mechanisms, most of them
of anthropic origin, that lead to the structuring of the landscape by acting on the
fragmentation of habitats. These habitats are organised on the basis of a ‘matrix’
(e.g., cultivated fields) or ‘patch’ (e.g. woods) architecture. These relictual forest
ecosystems may be organized in different ways: a continuum of forest and woodlands
interconnected by a bocage network or discontinuously.
The biological connectivity between the forest areas depends on the capacity
for dispersion of organisms and on the structure of the landscape network (shapes,
organization, etc.), the nature of the plots making up the matrix (e.g. size of the
agricultural plots, type of crop) and the distance between the forest habitats. The
study of the biological connectivity is thus a fundamental part of the analytical process