1 Ecological Indicators 6 (2006) 1 5 Introduction This article is also available online at: Ecological indicators: Theoretical fundamentals of consistent applications in environmental management Ecosystem theory and environmental practice have been separated by many factors and frontiers, although both sides could benefit from a closer linkage and a better communication. Practitioners often do not follow the deep analyses of theoretical fundamentals, although they feel the need of underpinning their concepts and approaches by theories. On the other hand, scientists are not primarily interested in applications, but in falsifying or quantifying their hypotheses. Hence, there is a permanent need to update or improve assessment processes and applications in environmental management by reviewing and interpreting theoretical fundamentals. Following this issue, the focal question of this volume, What can we learn from ecosystem theory for the derivation and the practical application of ecological indicators? is situated within the high conceptual gradient between the complex demands and methodologies of ecological theories on the one hand and the practical requirements of environmental assessments on the other. Indicators seem to be useful tools to bridge that gap, because their main characteristics represent attempts to reduce complexity, to avoid too complicated measurements and to select simple methods, which nevertheless can lead to a satisfying representation of a complex relationship. Therefore, indicators are also well-suited instruments to apply the results of ecosystem research to a broader field of utilisation. In September 2003, 37 scientists from Australia, Denmark, Germany, Italy, Portugal, Slovenia and the USA came together at the Villa Vigoni in Northern Italy to discuss the recent development in the area of ecological indicators and indications. The conference was partially supported by the Deutsche Forschungsgemeinschaft. Besides the focal point-of-interest the potential linkages between theory and practice in environmental indication the following targets were set: To exchange information on the derivation, development, utilisation, evaluation and interpretation of ecological indicators. To discuss the potentials of qualitative improvements of indicator systems. To investigate the potentials of ecosystem research and ecosystem theory to be up-scaled to the landscape level. To discuss methods and tools for a better indication concerning modern concepts of environmental protection, such as ecosystem health or ecological integrity. To look for improved possibilities to implement theory based indicator systems for a sustainable land- scape management in an interdisciplinary context. In the following volume, a set of 19 papers is published, which can be used to illuminate the diversity of requirements, conceptions, approaches and methodologies related to ecological indication. The presentations have been arranged along the following sequence of questions: Which are the fundamental ideas of ecosystem theory to indicate ecosystem or landscape states? X/$ see front matter # 2005 Elsevier Ltd. All rights reserved. doi: /j.ecolind
2 2 Introduction / Ecological Indicators 6 (2006) 1 5 The recent state of ecosystem theory can be characterised by an accentuation of developmental processes of ecological entities in a combination with systems analytical concepts from thermodynamics, network theory and synergetics. Although these approaches seem to be far away from real environmental objects, they can offer a lot of ideas for the derivation of consistent indicator sets. In the first paper of this theoretical series, B.C. Patten demonstrates a general approach, which originates in network theory. He understands indicators as low signal/noise read-outs from systems reflecting deeply embedded processes and defines criteria for the quality of ecological indication on this basis. Focal variables of these properties are observability and controllability. Patten discusses the indicator problem from the viewpoint of network models, environ theory and network enfolding, and provides a case study from wildlife management. Besides network theory, thermodynamics provides some powerful concepts to derive ecological indicators. S.E. Joergensen demonstrates the principle of eco-exergy optimisation in relation with ecological buffer capacity as holistic approaches for the description and evaluation of ecosystem states. His theory is based on the idea that certain variables behave as orientors, that is, they are optimised throughout non-disturbed successional processes and thus can be used to characterise an ecological system. In his paper Joergensen relates these systems attributes with descriptors of ecosystem health and distinguishes different growth forms, referring to biomass, network and information. He suggests that the exergy measures are good indicators for ecosystem health. While Joergensen s approach is based on the dynamics of exergy storage, A. Ludovisi introduces a ratio of the entropy produced and the exergy stored. Thus, he includes the distinct demands of growing ecosystems for maintenance as well as the significance of loss processes, both reflected in the produced entropy. From his point-of-view, the minimisation of this ratio is another orientor of ecosystem development. His concept is illustrated by case studies from different shallow lakes. A third application of thermodynamic indicators is provided by J. Patricio et al. The authors have observed the structural and functional dynamics after the re-colonisation of intertidal rocky ecosystems at the coast of Portugal. The multiple variables measured are analysed statistically with emphasis on the question whether biomass or complexity are developing more quickly. Their results show that the indicator eco-exergy provides useful information about the structural development of the community. In addition, the authors stress the significance of spatial scales, referring to the specific disturbance and the disturbed area. Following this paper, S. Bastianoni et al. introduce the indicator empower in comparison with the maximum exergy principle, from a practical viewpoint. They found that there is a temporal sequence, starting with a maximisation of empower, which is followed by exergy optimisation. As a result of these contributions it becomes clear that there is a high correlation between the different thermodynamic variables. Furthermore, the paper shows that the thermodynamic indicators can be distinguished due to their suitability to depict different states of ecosystem development. F. Müller et al. provide an application of the thermodynamic and synergetic indicator concepts at the landscape scale, using the outcomes of empirical ecosystem research, model scenarios and GIS techniques. The utility of their ecosystem indicator set is assessed with reference to retrogressional successions in wetland ecosystems and as a basis for catchment matter balances. Besides the observed changes of carbon and nitrogen sink functions to very efficient landscape sources, the indicators are discussed critically, whereby, i.e. entropy production is correlated with problems due to heavy mineralisation processes in the soils of drained wetlands. Which community features can serve as objects of ecological indication? Within this section, the potential of biocoenotic indicators to represent the health of ecosystems and landscapes is demonstrated: E. Padoa-Schioppa et al. present data from aquatic ecosystem analyses, forest landscapes and agricultural ecosystem complexes. Their contribution does not only include the utilisation of species abundance dynamics, but also the potential of body size theory to indicate the
3 Introduction / Ecological Indicators 6 (2006) health of ecological systems. A general discussion of biodiversity indicators is provided by K. Dierssen, referring to botanical sub-systems. He puts emphasis on the idea that besides the fundamental aspects of diversity additional properties of community composition have to be considered (e.g. the relationship between autochtonous and allochtonous species, life strategy types, hemerobic steps). The results of some case studies from Northern Germany finally lead to a discussion of the necessity to apply the ecosystem approach of the UN Convention of Biodiversity within a comprehensive framework. How can theoretical ideas be used to represent the impacts of specific disturbances? In this section, the roles of indicators concerning ecosystem reactions after disturbances are discussed. I. Petrosillo et al. show methods how to indicate the fragility of socio-ecological landscape systems in relation to tourism pressures, conducting a risk assessment study of the Salento region in Southern Italy. Their approach combines Holling s sustainability model with a concept of landscape fragility, and as a result a set of operational indicators is provided and applied. A second class of key disturbances, ecotoxicological effects, are discussed in the paper from O. Fränzle. He reviews the indicative quality of bioindicators, their typology and different concepts of indicator selection. Potentials and limitations of bioindicators are discussed, and emphasis is put on a combination of these variables with fuzzy logic approaches for an evaluative data interpretation as well as the requirement for rigid criteria referring to spatial and temporal representativeness. This feature is also analysed in the paper of R. Pesch and W. Schröder, who provide a report on their indicator works with reference to atmospheric pollution by heavy metals and the use of mosses as passive bioindicators. Basing upon applied geostatistics and aggregated statistical indices, patterns of heavy metal accumulations are presented for the whole territory of Germany. Which approaches can be used to indicate landscape states? In this group of papers, landscapes are investigated as objects of ecological indication on a variety of scales and with a variety of questions and approaches. The starting point of B. Jessel s article is landscape function, focussing on the information function. She states that in environmental evaluations, also the visual landscape has to be considered and presents some general hypotheses on human landscape perception. In a theoretical framework, visual elements, characteristics and characters of landscapes are distinguished, and the significance of qualitative aspects of landscape evaluation is underlined. Another applied aspect of landscape indication ispresentedbyw.schröder and G. Schmidt. They provide information about indicators used to estimate the dispersal and persistence of genetically modified rape. Coupling remote sensing techniques, GIS, individual based models and statistical procedures, regional risk assessments are carried out and monitoring schemes are constructed. A more general landscape based approach is then presented by G. Zurlini et al., concentrating on the resilience of landscape segments. The authors understand the present states of ecosystems as ecological phases of the adaptive cycle, which alternates between long periods of resource aggregation and transformation and shorter periods, which create opportunities for change and innovation. Resilience is used as a key variable of these states, and an operational framework is presented to derive respective indicators. The last article of this section is placed on a much broader scale: J. Walker et al. show concepts and results to assess the environmental conditions of catchments in Australia. Their assessment uses existing biophysical data obtained by satellite imagery, digital elevation models and other official sources as basic information for an inventory of an area of 2 million km 2. A number of indicators and indices are presented referring to their regional distribution patterns. How can we use indicators for a better environmental management? The last section of this volume deals with applications of ecological indicators in landscape
4 4 Introduction / Ecological Indicators 6 (2006) 1 5 evaluation, regional eco-audits, landscape planning and environmental decision making. Starting with O. Bastian and M. Lütz a methodology for the development of local agri-environmental measures is described and exemplified, which is based on state and pressure indicators and a functional landscape assessment. Thereafter, R. Collantonio- Venturelli and A. Galli demonstrate a case study from Central Italy, where a set of ecological indicators has been applied in landscape management. The concepts of the following publications are more fundamental: H. Wiggering et al. are developing an indicator set to assess sustainable land development, combining economic and ecological aspects in the framework of multifunctional land use. Illustrated by examples from agricultural production schemes, an indicator of social utility is introduced, and concepts for its applications are generated and demonstrated. The group of papers on applied aspects of environmental indication ends with the contribution of R. Lenz and D. Peters. They provide six case studies to illustrate the potential for application oriented landscape research in bridging human and natural sciences. The paper examines uncertainty, data modelling, the role of scenarios, and the use of process-oriented and participatory methods. Finally, the development of an integrative framework, an Environmental Impact Assessment Multi- Level Approach is suggested. Focal points of the discussions This collection of articles shows the broad bandwidth of approaches between very theoretical concepts and applied methodologies in environmental indication. It is also visible that up to now a couple of fundamental rules in ecological systems have not been widely used in environmental management, although, e.g. integrative and holistic approaches in assessment and application have to be intrinsicly based on, e.g. systems theoretical concepts. Therefore, the participants of the workshop have seen a big demand to fill this gap in the future. Both sides (theoretical ecologists and environmental practitioners) should communicate more intensively and link their approaches and demands, in the future. Consequently, the attempts of the Vigoni workshop 2003 can be seen as a first step only, and the papers of this volume should be understood as a demonstration of the state at the starting point. While integrating these demands, many other requirements of indicator derivation and application should be investigated and improved. Throughout our discussions, the following points have been discussed with special emphasis: Selecting emergent properties as indicators: If the general state of ecosystems is used as an indicandum (which is an important target), the respective indicators should be capable of really representing ecosystem features instead of single variables; ecosystem indicators should be ecosystemic variables on the ecosystem level-of-integration. Realising the dominance of indirect effects in indicator development: Although many environmental crises should have shown the significance of indirect, chronical and de-localised effects, this knowledge has not been adopted in indicator development to a satisfying degree up to now. Utilising systems analyses techniques for environmental indication: The design of indicator sets could take an enormous benefit from a stronger utilisation of systems analysis methods. Even very simple conceptual models can be very helpful to overview the topic. Simulation models are good tools and synthesisers for cooperation, they can be used to aggregate indicators and to produce indices. Models furthermore can be used as scenario instruments in predictive monitoring, producing an enormous efficiency of monitoring activities by showing the risks of potential developments. Therefore, structures for an institutionalised modelling should be built up. Coupling biological and non-biological factors: Attempting to find results on the ecosystem level, indicators of structures, processes, functions and organisation have to be combined. In this context the potentials and limitations of abiotic and bioindication have to be defined. Improving theory, terminology and general methodology of indicators: There is a lack of basic rules, methods and principles of indicator derivation and application. In too many cases indicator sets are developed without a satisfying scientific fundament.
5 Introduction / Ecological Indicators 6 (2006) Consequently, scientists should contribute to the development of a theory of indication. Coupling indication and prediction for risk assessment: Models should be used as instruments for the interpretation of indicator dynamics. They can depict risks and long-term effects of different political decisions. Indicating environmental conditions on different scales: There is still a high demand of theoretical investigations and practical implementations concerning the question how a certain indicandum can optimally be represented on different scales and how these scales are interacting. Future work should be concentrated on the extrapolation methodologies and scaling procedures of ecological indicators. Optimising the number of indicators and the complexity of indicator systems: There is a huge difference between scientists and politicians concerning the design of indicator sets while scientists prefer to work with many different variables which can depict the real complexity of nature, politicians want to found their decisions on an extremely small number of variables. In this aspect, both parties have to make compromises. The optimal ways to do this and the optimal levels of indicator aggregation for specific purposes are not clear up to now. Developing modern concepts of landscape management in the framework of the sustainability concept: The concepts of health and integrity have to be worked out on a more concrete level, including proposals for their indication and evaluation. Coupling ecological, social and economic indicators: A basic task, which is originating in the sustainability concept is the linkage between the different fields of sustainability. Therefore, ecologists have to think about strategies how to derive features for the socio-economic consequences from the dynamics of the ecological indicators. Coupling indicators with environmental targets and limits: Many problems concerning the evaluation of indicators, problems related to shifts of paradigms (e.g. from stability to development and adaptability), the problem of normative loadings of indicators can be solved by a team building initiative which is oriented towards the linkage of political eco-targets and scientific ecological variables. Optimising the presentation strategies of ecological indicators: A big problem arises throughout the presentation of complex indicator approaches. The result should be as simple as possible, but it should also reflect the system states on a suitable scientific level. This conflict between simplicity and accuracy, between complex indicator sets and a small number of understandable indices has not been solved up to now. Finding optimal conditions for cooperation: As an overall target, the support of cooperation can be taken into account. We must find better ways of communication between fundamental and applied scientists as well as better and more productive interactions between scientists and decision makers in general. For many of these questions, the process of solution finding is still in an initial state. Many problems are still ahead of us, i.e. concerning the application of ecosystem concepts, which seem to be too complicated to be used for rapid applications. Therefore, one result of the conference was to start an initiative to demonstrate the necessity of ecosystem monitoring and the practical potentials to implement this strategy in environmental management. May be this work will be another step to prove the old statement that nothing is as practical as a good theory. Felix Müller* Ecology Centre, University of Kiel, Olshausenstrasse 75, D Kiel, Germany *Corresponding author. Tel.: ; fax: Roman Lenz Institute of Applied Research, Nürtingen University, Schelmenwasen 4-8, D Nürtingen, Germany address: