What are indicators? On the definition of indicators in ecology and environmental planning

Abstract The term “indicator” is frequently used at the interface between science and policy. Although there is a great demand for clear definitions of technical terms in science and policy, the meaning of indicator is still ambiguous. In this contribution, we analyze different meanings of the term in ecology and environmental planning, suggest a general definition, and make recommendations for its appropriate use. We determined that the ways in which indicator is defined differ greatly, and some definitions are mutually exclusive. We arrived at the conclusion that a broad definition of the term is feasible. We recommend distinguishing between indicators as ecological components, i.e., ecological units, structures, or processes and as measures, i.e., properties of a phenomenon, body, or substance to which a magnitude can be assigned, and between descriptive and normative indicators. This clarification prevents the term “indicator” from becoming a meaningless buzzword, improves communication among stakeholders, and assures the testability of theories that include indicators. To avoid problems based on different understandings of the term and to maintain integrity in its use, we advise always providing a definition of the indicator term.

[1]  W. Scott Overton,et al.  An EPA program for monitoring ecological status and trends , 1991, Environmental monitoring and assessment.

[2]  David W. Andison,et al.  Guiding principles for developing an indicator and monitoring framework , 2004 .

[3]  S. Bell,et al.  Sustainability Indicators: Measuring the Immeasurable? , 1999 .

[4]  Gerald J. Niemi,et al.  Application of Ecological Indicators , 2004 .

[5]  G. Majone.  The Uncertain Logic of Standard Setting , 1982 .

[6]  David R. Patton,et al.  Is the Use of Management Indicator Species Feasible , 1987 .

[7]  C. O. Fraser.  Measurement in psychology , 1980 .

[8]  José Tormos,et al.  Conservation of European environments: The Spheciformes wasps as biodiversity indicators (Hymenoptera: Apoidea: Ampulicidae, Sphecidae and Crabronidae) , 2005 .

[9]  Devra G. Kleiman,et al.  Improving the Value of Conservation Programs , 2000 .

[10]  Juha Helenius,et al.  Value of semi-natural areas as biodiversity indicators in agricultural landscapes , 2004 .

[11]  K S Shrader-Frechette.  Comparative risk assessment and the naturalistic fallacy. , 1995, Trends in ecology & evolution.

[12]  Erin Seekamp,et al.  Understandings of Environmental Quality: Ambiguities and Values Held by Environmental Professionals , 2003, Environmental management.

[13]  Ernest W. Adams,et al.  On the nature and purpose of measurement , 1966, Synthese.

[14]  Knut H. Alfsen,et al.  Environmental quality indicators: Background, principles and examples from Norway , 1993, Environmental and Resource Economics.

[15]  Ian D Thompson.  Monitoring of Biodiversity Indicators in Boreal Forests: a Need for Improved Focus , 2006, Environmental monitoring and assessment.

[16]  C. Hempel.  Philosophy of Natural Science , 1966 .

[17]  Joanna Burger,et al.  Bioindicators: A Review of Their Use in the Environmental Literature 1970–2005 , 2006 .

[18]  Gert Rosenthal,et al.  Selecting target species to evaluate the success of wet grassland restoration , 2003 .

[19]  Andrew A. Whitman,et al.  Biodiversity Indicators for Sustainable Forestry: Simplifying Complexity , 2006 .

[20]  C. Pankhurst,et al.  Biodiversity of soil organisms as an indicator of soil health. , 1997 .

[21]  M. Patton.  Qualitative research and evaluation methods , 1980 .

[22]  C. J. West,et al.  Naturalization and invasion of alien plants: concepts and definitions , 2000 .

[23]  I. Zonneveld.  Principles of bio-indication , 1983, Environmental monitoring and assessment.

[24]  R. Kolkwitz,et al.  Ökologie der tierischen Saprobien. Beiträge zur Lehre von der biologischen Gewässerbeurteilung , 1909 .

[25]  D. Pearson,et al.  Selecting indicator taxa for the quantitative assessment of biodiversity. , 1994, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[26]  Ulrich Köpke,et al.  Bio-resource evaluation within agri-environmental assessment tools in different European countries , 2003 .

[27]  P. Bievre.  The 2007 International Vocabulary of Metrology (VIM), JCGM 200:2008 [ISO/IEC Guide 99]: Meeting the need for intercontinentally understood concepts and their associated intercontinentally agreed terms. , 2009 .

[28]  John R. Spence,et al.  Arthropods as ecological indicators of sustainability in Canadian forests , 2006 .

[29]  G. F. Mcisaac,et al.  Natural Environment and Human Culture: Defining Terms and Understanding Worldviews , 1999 .

[30]  D. Noble,et al.  Developing indicators for European birds , 2005, Philosophical Transactions of the Royal Society B: Biological Sciences.

[31]  Anselm L. Strauss,et al.  Basics of qualitative research : techniques and procedures for developing grounded theory , 1998 .

[32]  G. Hughes,et al.  Evaluating predictive models with application in regulatory policy for invasive weeds , 2003 .

[33]  Julian D. Olden,et al.  On defining and quantifying biotic homogenization , 2006 .

[34]  Rudolf Carnap,et al.  Logical foundations of probability , 1951 .

[35]  Kelly R. Munkittrick,et al.  Bioindicators Versus Biomarkers in Ecological Risk Assessment , 2002 .

[36]  N. Koper,et al.  Effects of Habitat Management for Ducks on Target and Nontarget Species , 2006 .

[37]  Jean-Michel Roberge,et al.  Usefulness of the Umbrella Species Concept as a Conservation Tool , 2004 .

[38]  O. Fränzle,et al.  Complex bioindication and environmental stress assessment , 2006 .

[39]  Rainer Walz,et al.  Development of Environmental Indicator Systems: Experiences from Germany , 2000, Environmental management.

[40]  M. Loughlin,et al.  On the buzzword approach to policy formation. , 2002, Journal of evaluation in clinical practice.

[41]  S S Stevens,et al.  On the Theory of Scales of Measurement. , 1946, Science.

[42]  Klaus Henle,et al.  Biological Indicator Systems in Floodplains – a Review , 2006 .

[43]  W. D. Hudson.  The Is-Ought Question , 1969 .

[44]  Reed F. Noss,et al.  Assessing and monitoring forest biodiversity: A suggested framework and indicators , 1999 .

[45]  Janet Riley,et al.  Indicator quality for assessment of impact of multidisciplinary systems , 2001 .

[46]  Susan Leigh Star,et al.  Institutional Ecology, `Translations' and Boundary Objects: Amateurs and Professionals in Berkeley's Museum of Vertebrate Zoology, 1907-39 , 1989 .

[47]  Dennis D. Murphy,et al.  Coping with uncertainty in wildlife biology , 1991 .

[48]  Dennis D. Murphy,et al.  A NEW METHOD FOR SELECTION OF UMBRELLA SPECIES FOR CONSERVATION PLANNING , 2000 .

[49]  James O. Luken,et al.  Assessment and management of plant invasions , 1997 .

[50]  Tom Addiscott,et al.  Critical Evaluation of Models and Their Parameters , 1995 .

[51]  J. W. Thomas,et al.  Ecological Uses of Vertebrate Indicator Species: A Critique , 1988 .

[52]  Irving M. Copi,et al.  Introduction to Logic , 1962 .

[53]  Nigel E. Stork,et al.  Invertebrates as determinants and indicators of soil quality , 1992 .

[54]  M. Paoletti,et al.  The role of earthworms for assessment of sustainability and as bioindicators , 1999 .

[55]  Virginia H. Dale,et al.  Challenges in the development and use of ecological indicators , 2001 .

[56]  M. McGeoch.  The selection, testing and application of terrestrial insects as bioindicators , 2007 .

[57]  John M. Randall.  Defining Weeds of Natural Areas , 1997 .

[58]  Dietmar von der Pfordten.  Deskription, Evaluation, Präskription : Trialismus und Trifunktionalismus als sprachliche Grundlagen von Ethik und Recht , 1993 .

[59]  G. Yeates,et al.  Nematodes as soil indicators: functional and biodiversity aspects , 2003, Biology and Fertility of Soils.

[60]  M. Zacharias,et al.  Use of focal species in marine conservation and management: a review and critique , 2001 .

[61]  R. Lambeck,et al.  Focal Species: a Multi-species Umbrella for Nature Conservation Focal Species for Nature Conservation Lambeck , 2022 .

[62]  Emilio Padoa-Schioppa,et al.  Bird communities as bioindicators: the focal species concept in agricultural landscapes. , 2006 .

[63]  M. Diekmann.  Species indicator values as an important tool in applied plant ecology – a review , 2003 .

[64]  Vincent Carignan,et al.  Selecting Indicator Species to Monitor Ecological Integrity: A Review , 2002, Environmental monitoring and assessment.

[65]  M. Paoletti,et al.  Using bioindicators based on biodiversity to assess landscape sustainability , 1999 .

[66]  Christian Bockstaller,et al.  Indicators: Tools to Evaluate the Environmental Impacts of Farming Systems , 1999 .

[67]  Martin K. Obrist,et al.  Biodiversity indicators: the choice of values and measures , 2003 .

[68]  Kurt Jax,et al.  Ecological Units: Definitions and Application , 2006, The Quarterly Review of Biology.

[69]  Robyn L. Smyth,et al.  Defining Acceptable Levels for Ecological Indicators: An Approach for Considering Social Values , 2007, Environmental management.

[70]  P. Mccormick,et al.  A proposed framework for developing indicators of ecosystem health , 1993, Hydrobiologia.

[71]  Peter B. Pearman,et al.  Common species determine richness patterns in biodiversity indicator taxa , 2007 .

[72]  Maria E. Gulvik,et al.  MITES (ACARI) AS INDICATORS OF SOIL BIODIVERSITY AND LAND USE MONITORING: A REVIEW , 2007 .

[73]  Jeffrey E. Herrick,et al.  Soil quality: an indicator of sustainable land management? , 2000 .

[74]  J. H. O'Keeffe,et al.  An expert system approach to the assessment of the conservation status of rivers , 1987 .

[75]  Andrea Ruf,et al.  A maturity index for predatory soil mites (Mesostigmata: Gamasina) as an indicator of environmental impacts of pollution on forest soils , 1998 .

[76]  Kelly R. Munkittrick,et al.  Environmental biomarkers in aquatic toxicology: Fiction, fantasy, or functional? , 1996 .

[77]  Kurt Jax,et al.  Can We Define Ecosystems? On the Confusion Between Definition and Description of Ecological Concepts , 2007, Acta biotheoretica.

[78]  Adrian McDonald,et al.  PICABUE: a methodological framework for the development of indicators of sustainable development , 1995 .

[79]  S. Andelman,et al.  Umbrellas and flagships: efficient conservation surrogates or expensive mistakes? , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[80]  Werner Härdtle,et al.  On the theoretical concept of the potential natural vegetation and proposals for an up-to-date modification , 1995, Folia Geobotanica.

[81]  Paul Bertram,et al.  The Development and Implementation of Indicators of Ecosystem Health in the Great Lakes Basin , 2003, Environmental monitoring and assessment.

[82]  J. Karr.  Biological Integrity: A Long-Neglected Aspect of Water Resource Management. , 1991, Ecological applications : a publication of the Ecological Society of America.

[83]  G. Mace,et al.  The 2010 Biodiversity Indicators: Challenges for Science and Policy , 2007, Conservation biology : the journal of the Society for Conservation Biology.

[84]  F. Berendse,et al.  Validity of Ellenberg indicator values judged from physico-chemical field measurements , 2002 .

[85]  R. Ferris,et al.  A review of potential biodiversity indicators for application in British forests , 1999 .

[86]  David B. Lindenmayer,et al.  Future directions for biodiversity conservation in managed forests: indicator species, impact studies and monitoring programs , 1999 .

[87]  Mark Sagoff,et al.  Fact and Value in Ecological Science , 1985 .

[88]  Gary K. Meffe,et al.  Principles of Conservation Biology , 1995 .

[89]  Henk L. Mulder,et al.  Foundations For A Scientific Analysis Of Value , 1981 .

[90]  L. Finkelstein,et al.  Fundamental Concepts of Measurement: Definition and Scales , 1975 .

[91]  J. H. Langenheim,et al.  Language Analysis and the Concept "Environment" , 1957 .

[92]  R. Noss.  Indicators for Monitoring Biodiversity: A Hierarchical Approach , 1990 .

[93]  K. Kiehl,et al.  Establishment and persistence of target species in newly created calcareous grasslands on former arable fields , 2007, Plant Ecology.

[94]  Andrés Millán,et al.  Are Water Beetles Good Indicators of Biodiversity in Mediterranean Aquatic Ecosystems? The Case of the Segura River Basin (SE Spain) , 2006, Biodiversity & Conservation.

[95]  H. Dawah,et al.  Species :the units of biodiversity , 1997 .

[96]  L. Cronbach,et al.  Construct validity in psychological tests. , 1955, Psychological bulletin.

[97]  C. Pankhurst,et al.  Biological Indicators of Soil Health , 1997 .

[98]  Merle L. Bowen,et al.  Meanings of Environmental Terms , 1997 .

[99]  M. Hisschemöller,et al.  Ecological Indicators: between the two fires of science and policy , 2007 .

[100]  Carl G. Hempel,et al.  Fundamentals of Concept Formation in Empirical Science , 1952 .