The eco-field: A new paradigm for landscape ecology - UdG

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Email: [email protected]. Received 1 June 2003, Accepted 1 August 2003. ... defined a 'cognitive field' created by the interference between functional traits and the 'real world'. Species- .... This paradigm is able to link different emerging.
Blackwell Science, LtdOxford, UKEREEcological Research0912-38142004 Ecological Society of Japan191107110Original ArticleEco-field paradigm for landscape ecologyA. Farina and A. Belgrano

Ecological Research (2004) 19: 107–110

The eco-field: A new paradigm for landscape ecology Almo FARINA1* and Andrea BELGRANO2 1

Institute of Ecology and Environmental Biology, Faculty of Environmental Sciences, Urbino University, Italy and 2Department of Biology, University of New Mexico, 167 Castetter Hall, Albuquerque, New Mexico 87131, USA

In the spirit of the theory of biocomplexity and of the non-linear emergent characters of ecological systems, the eco-field is a new paradigm that integrates the vision of the landscape as a neutral matrix (like a habitat) in which organisms are living, and contemporarily as a product of the human mind. Eco-field is defined a ‘cognitive field’ created by the interference between functional traits and the ‘real world’. Speciesspecific environmental suitability is the result of the quality of the different eco-fields and the landscape becomes a cognitive entity. The eco-field paradigm can be extended to the emergent properties of the systems. The eco-field of emergences is the geographic space in which the emergent properties appear. The eco-field of organisms and the eco-field of emergences, like results of aggregated entities, have in common the multidimensionality of landscapes, refusing the vision of landscape like a neutral geographic matrix for organisms and processes. Key words: biocomplexity; eco-field paradigm; hierarchical level of complexity; landscape ecology theory.

Introduction Although it is a young discipline, landscape ecology has developed a consistent body of theoretical and empirical evidence based on the assumption that the environment is heterogeneous in terms of energy, resources, biomass and physical constraints, and that this heterogeneity is copied ultimately by organisms. Landscapes can be considered dense, complex, networks of interactions between environmental factors (both forms and patterns, and processes, or dynamics) that capture the implicit as well as explicit properties of the environment (Phillips 1999), and heterogeneity and diversity are patterns of these systems (Kolasa & Pickett 1991). The biocomplexity theory (Merry 1995; Cilliers 1998; Bradbury et al. 2000; Manson 2001) considers landscape to be one of the possible dimensions in which the complexity of our planet is realized (Thompson et al. 2001). During the past few decades several new ideas have been developed that deal with biocomplexity (e.g. system general theory by von Bertalanffy 1969; autopoietic organization by Maturana & Varela 1980; the biosemiotic model by Hoffmeyer 1997; and the ecosemiotic model by Kull 1998a,b; Noth 1998) but there are still many barriers between these theories, preventing the development of an integrated problem-solving science (Graham & Dayton 2002). Farina et al. (2003) argued that scientific thought is based on the assumption of an external, neutral com-

mon world. This vision, strongly supported by a reductionistic approach, fails to understand processes like ecological integration, self-organization and the emergence of new macroscopic structures (May 1974; 1976; Prigogine & Stengers 1984; May 1986; Kauffman 1993). Landscape ecology is today a very promising discipline that could greatly contribute to the investigation of biocomplexity with an inter- and trans-disciplinary holistic approach (Naveh 2000). This discipline is composed by two distinct souls (Farina 1993): the first explains the role of patterns in ecosystem processes; and the second emphasizes the role of human intervention in the dynamics of the natural systems. This double vision of landscape as a matrix composed of distinct patches of aggregated elements (vegetation, animals, human artifacts), and as a holistic entity in which the landscape is considered a container of physical as well as human mind processes, still persists separately. According to the second vision the landscape is considered a human-related entity composed of many processes that are ultimately detected by our senses, thus existing only in our mind (Farina 2000).

*Author to whom correspondence should be addressed. Email: [email protected] Received 1 June 2003, Accepted 1 August 2003.

108 A. Farina and A. Belgrano

The aim of this contribution is to describe the new paradigm of the ‘eco-field’ using the perception of the surroundings as a basis to define the environmental context in which every species operates, calibrates responses to environmental constraints and reacts by adaptive mechanisms. In this way we try to create a change from an absolute system of reference, the land mosaic, to a cognitive referential system in order to acquire new knowledge about the environmental context (Wu & Hobbs 2002). We will largely use a cognitive approach to capture the signals that organisms receive from their surroundings, even organisms without an explicit nervous system (Maturana & Varela 1980; Capra 1996).

Ecological niche and habitat Niche theory and the habitat paradigm are two milestones on which physiological ecology is based, however, under the perspective of biocomplexity they no longer seem able to explain the emergent ‘real world’. The physiological range across which organisms interact with resources has been considered by the classic niche theory (Grinnell 1917; Hutchinson 1957). The niche theory is very useful to describe species-specific adaptive mechanisms in action, but as stressed by Farina et al. (2003) this theory is unable to investigate the semiotic and cybernetic mechanisms that transfer the information of the life-trait into the ‘real world’ and vice versa. The habitat concept is so naturally accepted in ecology as well as in many other disciplines that it is considered a definitive dogma. Habitat means the place in which a species fulfills its biological requirements. We can say that one habitat is favorable and that another is unsuitable, considering habitat suitability according a binary choice 0–1. Habitat is considered the physical space where a species finds food, mating places and refuge (Mitchell & Powell 2002). A species can occupy a broad range of ‘habitat’ but search for food in restricted parts (small foraging niche). Habitat and niche are often used in a contradictory manner and become difficult to include within a common paradigm. Recently, Pulliam (1988, 1996) identified two population statuses within a specific population: a source and a sink population based originally on the demographic balance. Populations are considered source populations when the balance between newborn and death is more than 1. Populations are considered sink populations when this balance is less than 1. Locally, a sink population persists because individuals migrate from the surroundings. This concept can be extended to habitats, a source habitat occurs when the environ-

Ecological Research (2004) 19: 107–110

mental conditions are sufficient to fulfill the needs (food, shelter, territory) of organisms, a source habitat supports a source population. This model opens the road to a fuzzy vision of habitats and indirectly to the eco-field concept.

The eco-field concept The term eco-field is the contraction of the words ‘ecological field’, and means the physical (ecological) space and the associated abiotic and biotic characters that are perceived by a species when a functional trait is active (Farina 2000). The eco-field can be considered the interference space in which the mechanisms for collecting, concentrating, stocking, preserving and manipulating energy are active. This concept is strictly connected with the subjective universe or ‘Umwelt’ of the zoologist von Uexkull (1940). In summary the eco-field assumes that: 1 A species perceives differently scaled characters of the environment for every functional trait. 2 Environmental attributes are perceived and recognized according the function that is active at that time and every function corresponds to create a cognitive landscape as an integration of the eco-fields (Fig. 1). 3 Species adaptation is the result of different mechanisms acting at different levels of each eco-field. 4 Environmental suitability is the result of the combination of different eco-fields. 5 Priorities in energy intake and the integration with other survival mechanisms allow a continuous shift from one eco-field to another. 6 Local extinction, adaptation and geographic displacement (for mobile organisms) are determined by

Fig. 1. The landscape is the combined perception through the component eco-fields. This is a unifying principle that can be applied to every species. The habitat paradigm can be ‘ignored’ using this approach.

Eco-field paradigm for landscape ecology 109

Ecological Research (2004) 19: 107–110

Fig. 2. Organisms have at least three ways to cope with environmental changes: to go extinct, to migrate or to adapt to the new conditions. Their fate is determined by the combination of the different eco-field scores. In this example the model has created a completely favorable environment composed by eco-fields with the maximum score 1 (binary choice 0–1 imposed by the model).

the combination of the emerging suitability of the different eco-fields (Fig. 2), like a special case of Liebig’s law. 7 The genetic variability of a species is under the pressure of the suitability of each eco-field. 8 The landscape is the cognitive dimension of the ecological complexity in which patterns and processes are distributed in a geographic (cognitive) space.

Eco-field and emergent properties of the landscape Emerging characters appear from a set of interactions between a high number of parts (Muller 1997) and represent the main subject of aggregated complexity (sensu Manson 2001). Landscapes show emergent properties, such as, stability, resilience, fragility and diversity that can be empirically evaluated (this theory can also be adopted for other entities). The hierarchy that makes it possible to describe a landscape belongs to this proto-emergence (Muller 1997). The concept of cognition and teleonomy becomes difficult to apply when moving from individual to aggregate entities like populations, communities or landscapes. Nevertheless when an aggregate entity like a woodland patch is modified by fragmentation, by simplification of margins or by a decrease of connectivity many emergent properties are modified. The shape and size of these entities assume a dominant role. This is the main topic for the science of landscape although the mechanisms responsible of such effects are not completely explained. Adopting the paradigm of ecofield makes it possible to clarify most of these mecha-

nisms. This is necessary to create a model and to pose some assumptions: (i) emergent characters appear into an entity (patch) along a geographic continuum; (ii) the geographic distribution of scores of each emergence represents the eco-field for that specific emergence; (iii) shape and size, complexity of the focal mosaic affect the emergent eco-fields; (iv) for every emergent property of a system we can recognize a specific eco-field. In such a way we can define eco-fields. For example, a ‘stability eco-field’ is characterized by an area in which predictability, repetition of patterns, genetic reconnaissance, coalescence are shaping characters. A ‘novelty eco-field’ is active at the periphery, where instability, unpredictability, appearance of new patterns and genetic diversity are the main characters. A ‘diversity eco-field’ shows the distribution of community richness and abundance across a land mosaic, and in this case such an eco-field is conceptually related to the ‘hot spot’ of the biogeographers. This paradigm is able to link different emerging functions to the geographic space and to provide evidence for the existence of a spatial optimum. For instance if a forest is a self-organized entity it must have the capacity to create its limits and the ecotones correspond to the limits of such self-organized entities sensu Jorgensen et al. (1998).

Conclusion It is possible to describe a landscape using two different perspectives: 1 The individual based vision of the surrounding ecofield in which the different functional traits act like sensors concurring to the landscape perception. The eco-field approach allows a novel interpretation of the complexity integrating the mechanisms that are at the basis of the teleonomic properties of the species. 2 The emergence-based vision applied to aggregate entities by which a proto-cognition, produced by emergent properties, determines a specific mosaic. The two perspectives have in common the multidimensionality of the landscape, which is no longer considered a fixed neutral matrix but an aggregated collection of subjective or effective patterns and processes. The extension of the eco-field to the emergent characters of the landscape open new perspectives to the management of land mosaics by tracking the more sensitive areas to the emergent self-organizing characters of every ecological entity across a hierarchical level of complexity.

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