Brief History of Landscape Ecology

Landscape ecology is a young but well-recognized ecological discipline dealing with the spatial distribution of organisms, patterns, and processes. This discipline developed after the Second World War in central and eastern Europe as an applied science used to manage the countryside. It became popular as a basic science, especially in the US, only during the last two decades.

The theoretical and empirical bodies of this discipline are growing fast but not in a unified fashion (Wu and Hobbs 2002, Metzger 2008). A long and intense debate between ecologists has accompanied its development, but without yielding a concrete agreement about the disciplinary range, the basic paradigms, and its relationship with the dated ecosystems approach. Despite this uncertainty, landscape ecology has attracted several students from many different disciplines including geography, biology, engineering, planning and land management, countryside conservation and, more recently, economics. Ecologists and spatial modelers entered into this "cultural arena" only recently (INTECOL Congress of Syracuse, NY, 1986).

Three different themes can be recognized in landscape ecology during its evolution (Farina 1993) (Fig. 1.1). The first theme was inspired by the patterned complexity or the simplification introduced into the environment by human use. This approach considers the landscape as a mosaic of patches of forested, cultivated, and urbanized areas. According to this vision, humans are responsible for most of the land modifications. The active role of humans as principal modifiers is a central part of the research.

The second theme emerged in the US and deals with the ecology of large areas (landscapes). Such an approach seems extremely important for managing the remaining areas in which human disturbance has not been great or in which natural

Fig. 1.1 Three different visions of landscape ecology and major regions in which the different approaches have been developed (Farina 1993)

Europe USA

USA

processes are persisting in spite of continuous human development. Nature conservation in natural parks seems to be one of the major areas in which landscape ecology could be an effective tool for forecasting the changes both inside and outside such areas.

Broad-scale processes such as erosion or fire can be studied using a plethora of tools that span the application of remote sensing techniques, GIS, spatial metrics, and spatial statistics.

The third theme takes into consideration the processes that are dominated by a spatial context, particularly, the spatial arrangement of organisms in a matrix. Such an approach is very promising and attractive from many points of view. The spatial arrangement of organisms indicates the distribution of the resources, and secondly describes the relationships between and among populations and species. Although not yet well integrated into ecological disciplines, spatial ecology has favored the development of many new ideas and paradigms and has allowed conjunction under the roof of a robust framework of sparse but not for this reason less relevant theories (e.g. Island Biogeography, MacArthur and Wilson 1967; Meta-population theory, Hanski and Gilpin 1997), paradigms (e.g. Ecological complexity, Levin 1999) and models (e.g. source-sink model, Pulliam 1988).

For each vision it is necessary to adopt specific paradigms. The European landscape ecology approach requires implementation of social and economical human models into the landscape domain. The ecology of the landscapes investigates the functioning of the mosaics and requires a robust theory of mosaics (see Chapter 2). Finally, spatial ecology considers the effects of shape and spatial arrangement of mosaic components on the behavior and on the physiology of plants and animals.

Landscape ecology for many years was considered a discipline quite remote from the ecological realm, but today the reduced hostility of traditional ecolo-gists, has allowed the incorporation of contributions from landscape ecology into the canonical sessions of the most important congresses of ecology.

Unfortunately most ecology textbooks don't reference landscape arguments, although recently some examples have begun to appear (Dodson et al. 1998). The reason for such diffidence is based on at least two different problems. The first is the development of a theoretical basis for landscape without taking into account the paradigms that form the basis of traditional ecology. It seems that landscape ecolo-gists have elaborated new ideas and paradigms starting from a different perspective than that in which ecology is rooted. I suspect that human processes have been so far outside ecological arguments for so long that the sudden recognition of such a plethora of topics bypasses the "cultural niche" and "cage" in which ecology has been developed.

A second problem is due mainly to misuse of landscape ecology's paradigmatic and theoretical approach in technical procedures for land evaluation and planning. Often environmental practitioners and landscape architects have extensively used landscape concepts, procedures, and metrics without the necessary experimental or empirical verification, assuming the exactness of tools not fully validated. This is particularly evident in the quantitative approach to the study of landscapes. Although many metrics are now available to measure the regularities/irregularities of landscape shape, their behavior is not fully explained by the processes that we intend to evaluate (e.g. Bogaert 2000, Bogaert et al. 2002).

I argue often that in the "real world," and outside the academic microcosm, efficient approaches to manage and solve problems are urgently required. This has been especially true during the past few decades in which the technological revolution has extended from agriculture to industry, and to all functioning of society. It has strongly impacted the environment, displacing processes and creating pathologies in many functional segments at a broad range of spatial and temporal scales.

One criticism cited against landscape ecology is based on the "superficiality" by which we give credit to spatial patterns. For instance, the concept of the corridor is abused for many purposes when not connected with a specific process or organismic life trait, and over-evaluating the role of such structures often confuses patterns with processes.

Other examples are from the common practice to use thematic maps to organize protected areas or other focal management areas. The world that we represent on maps is perceived differently by different organisms, and this creates a discrepancy between the objects observed by using human perception and their role in the environmental realm.

Finally, we are assuming a much too simplified vision of environmental complexity. It seems landscapes approach an intermediate phase from a functional perception of the environment (ecosystemic ecology) to the patterned "geographic" ecology, although fractal geometry (Mandelbrot 1977) and macroecology (Brown and Maurer 1989, Brown 1995) have opened new perspectives.

In my opinion, and this is the reason for this book, there should exist other levels in which the environment organizes function and patterns. To discover such levels it is necessary to create and use new paradigms and to formulate new theories. Another important task consists of fighting against the conservative reactions of "normal science" practitioners who move between auto-ecology and ecosystem science and landscapes without conceptual bridging and integration.

The emergent discipline of landscape ecology in which theoretical and applied fields are recognized (Naveh and Lieberman 1984, Forman and Godron 1986, Forman 1995, Zonneveld 1995), contributes to an integration of ecosystem paradigms with spatial processes across a broad range of spatial and temporal scales (Delcourt and Delcourt 1988), as documented by a rich scientific literature arising around this new theme (Farina 1998, Farina 2006, Dodson et al. 1998) and the numerous debates (Naveh 2007, Antrop 2007).

The convergence toward the landscape includes the perspectives of geographers, biologists, ethologists, ecologists, wildlifers, and landscape architects. The integration of these perspectives has created a productive forum for matching new ideas and approaches and, at the same time, for developing a common framework in which to realize new conceptual syntheses.

Landscape ecology has played a central role in attempting to move a consistent portion of ecology from the past stagnant condition to which this science was relegated, at the end of the 1970s, to accept the challenge to conserve natural resources through more ethical land use and management.

In particular the landscape ecology approach to nature conservation and land management has produced a new impetus in applied sciences, including new conceptualizations of biodiversity (Richtie and Olff 1999, Whittaker 1999) and environmental health (Rapport et al. 1998).

Landscape ecology focuses mainly on patterns and processes scaled according to human perception of the landscape and considered at a spatial level between the ecosystem and the biome (Odum 1989). The study of human interference with natural systems and the possibilities of managing natural and man-made resources in a durable and nondestructive (sustainable) fashion are of special interest.

The ecology of the landscape considers the complexity of ecological systems at a large scale that supersedes the functional scale often associated with the composition of large-scale ecosystems. At this larger scale, many processes across different ecosystem boundaries encounter the heterogeneity of the living substrate, and thus the relationship between the component parts (patches, tesserae, ecotopes), becomes the main goal of the research (Turner 1989, 2005). Such an approach is consistent with the human-perceived landscape and allows the tracking of processes and organisms across regions, watersheds, and territories.

Finally, spatial ecology focuses on a plethora of processes and patterns that are associated with space. Special emphasis is given to the study of animal behavior and to the relationship between habitat structure and organism function. An experimental approach using microcosms is of growing importance in the validation of spatially explicit models that apply statistical tools and fractal mathematics to plants and animals (e.g. Barrett and Peles 1999).

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