Ecological Philosophy

(1 May 2014)


In this article, ecological philosophy is taken to refer to conceptual frameworks in ecological and environmental science (hereon: ecology), and as such combines theorizing in ecology with philosophy of science that focuses on ecology. The choice and organization of the references is governed by three premises: 1) The need for bibliographies is diminsihed by the ease of deriving rich sets of references through an internet search or from general reference works (including other Oxford Bibliography entries); 2) However, value can be added to a bibliographic contribution through categories that stimulate readers to review their own conceptual framework so as to identify gaps or oversights and to be more self-conscious about how they address (or deflect) conceptual challenges in the field; 3) A challenge faced by all ecologists (taken hereon to include environmental scientists) is to deal with ongoing change in the structure of situations that have built up over time from heterogeneous components and are embedded or situated within wider dynamics (Taylor 2005 [under #8 below]). Based on these premises, each category (after the first section on general works) corresponds to a different impulse regarding the conceptualization of ecological complexity. The impulses are arranged roughly in order of when they emerged or were emphasized, with references chosen to provide points of entry into the subsequent history more than the most recent contributions on a given issue. Cross-connections among impulses are noted.

An alternative meaning of the term ecological philosophy should be noted, namely, a worldview or conceptual framework that invokes ecology in promoting environmental protection or wider social actions. Although such ecological philosophies are not addressed directly in this article, they might be reviewed in relation to the same set of impulses. That is, suppose a philosopher of ethics describes interactions among moral agents in terms of analogies to predation, parasitism, and symbiosis and advocates sustainable management of those interactions. Following impulse #8 below, one could ask how that ethical theory would be affected by paying attention to changes in the hidden non-moral variables and the embeddedness of the interactions in wider social dynamics.

General Reference Works
Most of the sources in this section provide entry points into a heterogeneous selection of topics, addressed from the point of view either of philosophers of science (informed by the history of ecology) or ecologists concerned to clarify and advance the theoretical status of the field. The latter emphasis is evident in Pickett et al. (2007, first published in 1994), a systematic exposition of the integration of across disciplinary boundaries and levels of organization, the Synthese volume reprinted as Saarinen (1982), and the rich history of ecological conceptualizing surveyed in McIntosh (1985) and Schwarz and Jax (2011). These works temper a recurrent recent theme to the effect that “philosophy of ecology has been slow to become established as an area of philosophical interest” (Colyvan 2009). That theme may reflect what has been published or read by philosophers of science more than it does a shortage of philosophical or conceptual analyses of ecology.

Brown, Bryson, Laplante, Kevin de, and Peacock, Kent eds. 2011. Philosophy of Ecology Amsterdam: Elsevier.
Essays by philosophers that combine attention to conceptual issues in ecology and current issues in philosophy of biology, such as inference about causes, integration versus unification, function and teleology, identity and individuation of units, reduction and emergence, and historical science (see impulse #10). The first half focuses on many of the impulses covered in this article; the second half on applications of ecology to environmental issues.

Colyvan, M., et al. 2009. Philosophical issues in ecology: recent trends and future directions. Ecology and Society 14 (2):
To show how philosophy can contribute to ecology and conservation biology, four topics are reviewed: mathematical models as descriptive, explanatory, or normative; alternatives to standard models of hypothesis testing and the use of decision-theoretic methods based on utility-maximizing agents; understanding the diversity of biodiversity measures in relation to different aims of conservation management; and environmental ethics with a view to reconciliation with decision theory.

Cooper, Greg J. 2003. The science of the struggle for existence: on the foundations of ecology. Cambridge: Cambridge University Press.
Argues for Haeckel's definition of ecology as the study of the struggle for existence. On this basis, examines two areas of persistent controversy in ecology: the degree and causes of balance in regulation of populations; and the role of model building.

Cuddington, Kim and Beisner, Beatrix eds. 2005. Ecological Paradigms Lost: Routes of Theory Change Amsterdam: Elsevier.
Dividing ecology into broad areas, such as population, epidemiological, and ecosystem ecology, the development of major ideas is reviewed by ecologists and the nature of theory change is commented on by ecologists and philosophers of science. The editors conclude that theory change in ecology is gradual or evolutionary making it unwise for ecologists to “ignore the older history of their discipline” (p. 1).

Graham, Michael H., Dayton, Paul K., and Hixon, Mark A. 2002. Special Feature: Paradigms in Ecology: Past, Present, and Future. Ecology 83 (6): 1479-559.
Articles by ecological practitioners that address controversial issues, such a density-dependent versus independent regulation of population size, from the point of view of “how paradigms have contributed to the development… of ecology.” (The term paradigm is used here to connote a school of thought, not to engage with debates about the revolutionary versus evolutionary character of changes in theories in science; see Cuddington and Beisner 2005.)

Keller, David R. and Golley, Frank B. eds. 2000. The Philosophy of Ecology: From Science to Synthesis Athens, GA: University of Georgia Press.
A selection of 22 publications by ecologists, philosophers, and philosophically minded biologists (dating back to Möbius [1880-81] on the oyster bank as a social community) isorganized under five headings: Entities and process in ecology; Community, niche, diversity, and stability; Rationalism and empiricism; Reductionism and holism; and Ecology and evolution.

McIntosh, Robert P. 1985. 'Theoretical approaches to ecology'. In The Background of Ecology: Concept and Theory, 242-88. Cambridge: Cambridge University Press.
Surveys a wide range of approaches to and criticisms of theory in ecology during the twentieth century, including debates by ecologists about the appropriate way to conceive of the scientific enterprise.

Pickett, Steward T. A., Kolassa, Jurek, and Jones, Clive G. 2007. Ecological understanding; The nature of theory and the theory of nature. Burlington, MA: Academic Press.
Systematic development of a framework for understanding science that “can acccommodate the variety of seemingly disparate activities that [ecological] scientists practice” (p. viii). An integrated ecology would bring together four perspectives: ecological entities (“Things”) involve processes (“Stuff”), engage in self-maintenance (“Now”), and have history (”Then”).

Saarinen, Esa ed., 1982. Conceptual Issues in Ecology Dordrecht: Reidel.
Essays and critical responses by philosophers and ecologists, providing entry points into conceptual debates, especially those around impulses #3, 4, 7 to follow.

Sarkar, Sahotra. 2005. 'Ecology'. In The Stanford Encyclopedia of Philosophy. Edited by Edward N. Zalta.
This encyclopedia entry “treats experimental and theoretical work simultaneously with a bias in favor of those theoretical results [i.e., based on mathematical models] that are unambiguously testable.” Identifies seven problems as “philosophically intriguing,” which range from formalization indeterminacy—“apparently informally clear hypotheses can be translated into radically different formal counterparts”—through partial observability—“even the most basic parameters are often difficult to estimate accurately,” to uniqueness, in the sense that ecological entities are historically contingent and structurally complex.

Schwarz, Astrid and Jax, Kurt eds. 2011. Ecology revisited: Reflecting on concepts, advancing science Dordrecht: Springer.
This volume of 28 essays, which emerged from the project of a Handbook of Ecological Concepts (HOEK), provides an abundance of entry points to published literature. Each essay “facilitates rapid access to the (sometimes) conceptual content of [ecological] terms as well as providing in-depth information about their philosophical and historical context” (p.6). (The collection also serves as an antidote to a common Anglo-American bias in appreciating the range of ecological thinkers.) Schwarz's essay on “Dynamics in the formation of ecological knowledge” (p. 117-141) proposes that theories in the field oscillate among three conceptions, which correspond in large part to impulses #1, 2, and 3 to follow.

Hastings, Alan 2007-. Editorial – an ecological theory journal at last. Theoretical Ecology 1: 1-4.
In launching a journal which fosters theory directed “at the most pressing questions in ecology,” the editor reviews his choice of past “theoretical work in ecology [that has] had a large influence” (p. 1), seeing a common thread of “simplicity, elegance, and generality” (p. 3).

Impulse #1. Ecosystems and ecological communities are complex, yet have systemic properties
An ecosystem consists of the ecological community of different species in combination with the chemical and physical processes in its environment. A broad distinction can be made between systems ecology, which emphasizes nutrient and energy flows between compartments in the enrtire ecosystem (#2), and community ecology, which emphasizes population sizes and inter-species interactions (#3). Nevertheless, community ecological theory also involves well-bounded systems in which interactions within and among populations or feedback loops ensure self-regulation and persistence (Taylor 2005 [under #8]), as evident in Clements (1916) and, fused with systems ecology, in Odum (1969).

Clements, Frederic E. 1916. Plant Succession: An Analysis of the Development of Vegetation. Washington, DC: Carnegie Institution of Washington.
The community (or "formation") of plants colonizing an uninhabited site is like a developing organism; it passes through a predictable succession of stages, each providing the conditions for the following stage, and results finally in a stable, self-sustaining "climax.” The interactions among the species (especially competitive interactions) and the changes the species effect on the habitat provide the cause for this development. At the same time the climax is determined by the habitat and climate, suggesting the possibility of a "physiological" analysis of the complex organism responding to its external environment.

Odum, E. P. 1969. The Strategy of Ecosystem Development. Science 164 (3877): 262-70.
Adopting Clements's view of succession, Odum lists 24 attributes of ecological systems, contrasting for each “the situation in early and late development.” Adopting the work of his brother, H.T. Odum (#3), the list begins with 5 attributes of community energetics, which match a “fundamental shift in energy flows as increasing energy is relegated to maintenance” (p. 263).

2. Systems of compartments and flows of energy, nutrients, and information
In the early 1940s Hutchinson sponsored Lindeman's measurement and mathematical redescription of energy flows through trophic levels (plants, herbivores, carnivores), work taken up by H. T. Odum. With Odum the intermeshing of biological and physical aspects of systems opened the way to propose analogies based on properties of electrical circuits and, using energy as the universal currency, to advance theoretical propositions about living systems based upon thermodynamics, such as, ecosystems will develop until they maximize total energy flow per unit time (“maximum power”) (#1). In a similar spirit of mimicking the determinism of change in some physical systems, information-theoretic (Margalef 1968) or phenomenological (Ulanowicz 1986) formulations of ecosystem development have been proposed. However, unifying theory was not necessary for most systems ecologists of the 1960s and 1970s (but see Allen and Starr [under #6]); a central role was given to measurement (of the different flows in an ecosystem), in contrast to making experiments on well-controlled parts of the system (#5 vs. #7).

Margalef, Ramon. 1968. Perspectives in Ecological Theory. Chicago: University of Chicago Press.
Information theory is used to support the proposition that more mature systems, those with greater organization or structure, are maintained with relatively less energy per unit biomass.

Odum, H.T. 1982. Systems Ecology: An Introduction. New York: Wiley.
A synthetic text, which compares systems of widely varying kinds and contains around 1400 energy circuit diagrams. Many of these are not based on data, in line with the idea that the structure of the system is key, not detail about its components.

Ulanowicz, R. E. 1986. Growth and Development. New York: Springer Verlag.
Ascendency is proposed as a measure both of the flows in the ecosystem and their organization through interactions in the trophic web. Explicit affinities with maximum power and information theory are present.

3. Basic, general rules, especially about populations and their interactions
From the late 1950s on MacArthur championed the search for general theoretical propositions about regulation of population sizes and distributions (in space and in characters) through interspecific interaction (chiefly competition for limiting resources), propositions not dependent on historical particularities (Kingsland 1995, p. 176-205). He popularized the use of models, often mathematical, to formulate these propositions and relate them to patterns, i.e., observations that had some generality (MacArthur and Wilson 1967, Kingsland 1995). (Harper 1967 laid out an allied research program for plants, making more use of regularities observed for individual species and their changes in density over time.) The MacArthurian (or Levinsian 1966) strategy is that a model is useful for generating qualitative and general insights about communities, such as, MacArthur and Wilson's (1967) models for biogeographic patterns of species abundance on islands. Discrepancies between the model and observed patterns in nature imply that some additional biological postulates are needed. Qualitative insights and discrepancies together enable ecologists to generate interesting questions for investigation.

A notable example of such exploration of models concerns investigation of how complexity of communities is related to their persistence or stability. Originally, ecological theory implied that ecological complexity was able to persist because of the enhanced stability of complex ecological systems. However, mathematical analysis during the 1970s showed that complexity works strongly against stability unless the complexity is nearly decomposable, i.e., consists of loosely linked subsystems. This result opened up questions about the “devious strategies which make for stability in enduring natural systems” (May 1973, p. 174) as well as about the temporal development of complexity, not simply analysis of its current configuration (an emphasis already evident in studies of plant succession, e.g., Noble and Slatyer 1980) and about the embeddedness of communities in a larger landscape (#8). In contrast to “devious strategies,” Hubbell (2001) fits data on species richness and distributions of relative abundance to models in which all organisms of all species in a community follow identical rules of ecological interaction. Perspectives on complexity (and on evolution) have also come from exploring models that include variability within populations (i.e., among individuals) and in their resource environment (Łomnicki 1980) or non-linear dynamics (Odenbaugh 2011).

Harper, J. L. 1967. A Darwinian approach to plant ecology. The Journal of Ecology 55: 242-70.
Reviews a wide range of questions about numbers and density primarily of individual plant species, claiming that these have “a highly respectable origin in the ecological thinking of Darwin” (see #4).

Hubbell, Stephen P. 2001. The Unified Neutral Theory of Biodiversity and Biogeography. Princeton, NJ: Princeton University Press.
Species-area relationships on islands and the mainland as well as patterns of relative species abundance (i.e., numbers of common versus rare species) are explained with models that are neutral in the sense of treating organisms in a given trophic level of a community as identical in their demographic character (e.g., probability of giving birth). This calls into question accounts that invoke the different characters of different species to explain abundance in some environments and scarcity in others (see null models under #7).

Kingsland, Sharon. 1995. Modeling Nature: Episodes in the History of Population Ecology 2nd. edn. Chicago: University of Chicago Press.
In the decades of the mid-twentieth century, ecologists in field, laboratory, and modeling studies addressed the population as a level of focus for between the individual organism and the complexity of communities or ecosystems. A conflict or dialectic between ahistorical and historical thinking runs through that history.

Levins, Richard 1966. The strategy of model building in population biology. American Scientist 54: 421-31.
Sketches a strategy of model building in ecology and population genetics that favors sacrificing "precision to realism and generality." Models should be seen as necessarily "false, incomplete [and] inadequate," but productive of qualitative and general insights. In practice Levins's strategy applied to community ecological models simple enough to be analyzed mathematically, not to highly parameterized systems ecological models (#2) that required computer simulation. (Discussed in Taylor 2005, p. 34-46 [see under #8] and references therein.)

Łomnicki, A. 1980. Regulation of plant density due to individual differences and patchy environment. Oikos 35: 185-93.
Discusses a model in which unequal resource partitioning among individuals allows for stable populations, where equal partitioning does not. Also considers effects of heterogeneous environments and emigration.

MacArthur, Robert H. and Wilson, Edward O. 1967. The Theory of Island Biogeography. Princeton, N.J.: Princeton University Press.
Extending MacArthur's interest in regulation of communities to the explanation of biogeographic patterns, this book makes use of the abundance of islands to assemble and analyze data on species abundance in relation to models, such as, the number of species on an island being a balance between immigration (declining with distance from the mainland) and local extinction (increasing with species number and decreasing with the size of the island)

May, Robert M. 1973. Stability and Complexity in Model Ecosystems. Princeton, NJ: Princeton University Press.
Applies the MacArthurian approach of “seek[ing] to gain general ecological insights with the help of general mathematical models” (p. vii) to a range of topics, such as the complexity-stability relationship, persistence in fluctuating environments, time delays, niche overlap. Best known for the complexity begets instability result.

Noble, I. R. and Slatyer, R. O. 1980. The use of vital attributes to predict successional changes in plant communities subject to recurrent disturbances. Vegetatio 43 (1-2): 5-21.
Classifies plant species in terms of a small number of vital (life history) attributes, and on that basis examines possible pathways of succession given “different disturbance frequencies and intensities, and to the seasonal time of disturbance” (p. 20).

Odenbaugh, Jay. 2011. 'Complex Ecological Systems'. In Handbook of the Philosophy of Science, Volume 11 - Philosophy of Complex Systems. Edited by Cliff Hooker, 421-39. Amsterdam: Elsevier.
Uses the complexity-stability issue to highlight modelers use of “the tools and assumptions of linear dynamical systems” (p. 421), such as speed of return to equilibrium after a small perturbation. Non-linear dynamics have properties, such as sensitivity to initial conditions and the possibility of deterministic “chaos” (first explored in ecology by May) that have implications for issues in philosophy of science, such as, whether biology has laws.

4. Particularism
By the early 1980s ecologists of a particularistic bent were questioning many of community ecology's models (see #3 vs. #7); scepticism about the possibility (Simberloff 1980) and the practical utility (Schrader-Frechette and McCoy 1993) of general ecological theory became widely expressed. This impulse was prefigured in the 1950s by the non-system view of Andrewartha and Birch, in the 1920s by Gleason's (1926, 1927) emphasis on historically contingent, shifting associations, and, much earlier, by Darwin (1859)'s ecologically-rich third chapter.

Andrewartha, H. G. and Birch, L. C. 1984. The Ecological Web. Chicago: University of Chicago Press.
To explain the distribution and abundance of species ecologists should focus on one species at a time and, using their knowledge of natural history and of the animal's physiology and behavior, trace the direct and indirect influences on the animal's chance to survive and reproduce. This envirogram of influences consists of physical factors and other species, often acting independently of the density of the focal species.

Darwin, Charles. 1859 [1964]. On the Origin of Species 1st edn. Cambridge, MA: Harvard University Press.
The “Struggle for Existence in a large and metaphorical sense”includes getting food from other organisms, coping with drought, competing with other animals for food in times of scarcity, a parasite's finding of a host, and so on. That is, all evolution occurs in an ecological context. Observes that checks and relations among organisms are very complex and can produce unexpected results (see Wootton 1994 [see under #8]). For example, the introduction of one species, Scotch fir, into heathland led to the flourishing of many species of plants, insects, and birds not previously seen in the heath (p.71).

Gleason, H. 1926. The individualistic concept of the plant association. Bulletin of the Torrey Botanical Club 53: 1-20.
--- 1927. Further views on the succession concept. Ecology 8: 299-326.
The responses of Gleason (1926) to the community concept raise almost all the opposing terms in Anglophone debates in ecology since Clements (1916) (see #2). For integrated complex organisms Gleason substituted shifting associations. The properties of these associations are very contingent on the physical environment and the patterns of immigration from the surrounds—particular conditions that are not controlled by the association. It is more important to expose regularities through analysis of variable individual responses to variable environmental conditions than it is to delineate and classify communities and successional sequences (see #5). This follows because "succession is an extraordinarily mobile phenomenon, whose processes are not to be stated as fixed laws, but only as general principles of exceedingly broad nature, and whose results need not, and frequently do not, ensue in any definitely predictable way" (Gleason 1927).

Shrader-Frechette, Kristin S. and McCoy, Earl D. 1993. Method in Ecology: Strategies for Conservation. Cambridge: Cambridge University Press.
Presents a philosophical basis with an extended case study to argue for ecology based on case studies from which regularities might be derived. More general theory in community ecology (#3) does not have the “precision, explanatory power [or] empirical adequacy” for addressing practical environmental problems.

Simberloff, D. 1982. The status of competition theory in ecology. Annales Zoologici Fennici 19: 241-53.
Many factors operate in nature and in any particular case at least some of them will be significant. A model cannot capture the relevant factors and still have general application. Instead, ecologists should intensively investigate the natural history of particular situations and test specific hypotheses about these situations experimentally. They may be guided by knowledge about similar cases and may add to that knowledge, but they should not expect their results to be extrapolated readily to many other situations.

5. Patterns might reveal influences on dynamics
Important influences might be evident in patterns in ecological complexity, as revealed in diversity measures and other community descriptors or through multivariate analyses. Measurement and comparison of diversity of species at different sites (Pielou 1975) follow a long history of natural history as well as the particular aspiration of Clements (1916) that patterns might point to the underlying “physiology.” In practice, however, such studies provide description and classification more than insight about mechanisms. The views of Gleason (1926, 1927) gained adherents in the 1950s when plant ecologists, using multivariate statistical methods, found that vegetation data can be better described as continua (ordination); delineation (classification) into communities is more or less arbitrary (McIntosh 1967). Vegetation ecologists continued to develop methods of exposing patterns in vegetation data and using those patterns aim to generate hypotheses about the underlying causal gradients. By the 1980s, however, it had been shown that the results of pattern analyses are sensitive to the models underlying the technique used and the sampling of sites from the space of environmental possibilities. Popular techniques, when tested on simulated data, do not recover well the simulated environmental gradients. Techniques that reduce this model-dependence also tend to produce degenerate patterns (Minchin 1987). The Catch-22 is that one needs to know a lot about the causal factors behind the data in order to design efficient and distortion-free multivariate techniques that would expose those factors (Austin 1987, but see Grime 2001 [under #6]). Beyond plant ecology, starting in the late 1970s, data on entire food webs has been analyzed with a view to discerning regularities in the web or network topologies and making “suggestions as to how food webs have come to organize themselves” (p. 1644 in review by May 2009, linking this line of research to #3). More recently, explanatory puzzles have emerged from showing that, while biodiversity is being lost worldwide, decline in diversity is not so evident at the local level even with rapid turnover in community composition (Dornelas et al. 2014).

[Annotations of the following references can be read in the overview above.]
Austin, Michael P. 1987. Models for the analysis of species' response to environmental gradients. Vegetatio 69: 35-45.
Dornelas, Maria, et al. 2014. Assemblage Time Series Reveal Biodiversity Change but Not Systematic Loss. Science 344 296-99
May, Robert M. 2009. Food-web assembly and collapse: mathematical models and implications for conservation. Philosophical Transactions of the Royal Society B 364: 1643–46.
McIntosh, Robert P. 1967. The continuum concept of vegetation. The Botanical Review: 130-73.
Minchin, Peter R. 1987. An evaluation of the relative robustness of techniques for ecological ordination. Vegetatio 69: 89-107.
Pielou, E. C. 1975. Ecological Diversity. New York: Wiley.

6. Natural scales
The delineation of nested units—from organisms, through populations, communities and ecosystems, to the biosphere—continues to be employed in textbooks, primarily for expository convenience, but it may also be used to state or imply claims about separability of scales and the persistence of units around which observations and theory can be built (Jax et al. 1988). The prospect of finding a hierarchy or natural scales of patterns and processes was actively pursued from the early 1980s in work that drew from both systems ecology (see #2) (O’Neill et al. 1986) and vegetation ecology (see #5) (Allen and Starr 1982). In particular, does heterogeneity disappear or can it be managed through choice of scale? (Kolasa and Pickett 1991) A landscape ecology received fresh attention at the same time, eventually acknowledging its longer history in European research and addressing currents or aspirations (not all of which concern natural demarcation of scales for patterns and processes of organisms and material/energy flows; Kirchhoff et al. 2013). A separation of the scale of individual species from their context had been evident from the late 1960s in plant ecology's focus on demographic strategies of individual species (how they colonize, grow, survive, disperse, etc.; Harper 1967 [under #3]) as if, following Gleason (see #4), ecological organization, where it exists, is a contingent and perhaps temporary outcome of underlying processes (but see Grime 2001). The evolutionary emphasis of Harper and many others raises issues of the separateness of ecological and evolutionary time scales—has the ecological context had a more or less consistent effect for the period of time implied by evolution of the purported adaptation (Taylor 2001)?

By the late 1980s the power of computers allowed modeling of diverse individuals in place of homogeneous populations (DeAngelis and Gross 1992), which suggests that linking patterns of ecological complexity to underlying processes will not look like long-standing physical and chemical theories, such as thermodynamics, in which macro-regularities arise statistically from large numbers of similar entities (see #2). Similarly, the heterogeneity of units in ecology and their disparate temporal and spatial scales of activity (#8) limits the relevance of complexity theory in which iterations of simple rules over time and space lead to complex behaviors for which parallels in real-life are suggested (Anand et al. 2010).

Allen, T. F. H. and Starr, Thomas B. 1982. Hierarchy: Perspectives for Ecological Complexity. Chicago: University of Chicago Press.
One hope of hierarchy theory is that, if the right measure is found for extracting patterns from data, a natural reduction of complexity might be achieved.

Anand, Madhur, et al. 2010. Ecological Systems as Complex Systems: Challenges for an
Emerging Science. Diversity 2: 395-410.
“Highlights… features of ecological complexity—such as diversity, cross-scale interactions [#10], memory and environmental variability—that challenge classical complex systems science.”

DeAngelis, Donald L. and Gross, Louis J. eds. 1992. Individual-based Models and Approaches in Ecology: Populations, Communities, and Ecosystems New York: Chapman and Hall.
The implications of distinguishing among individual organisms (in their characteristics and spatial location) within a species is examined in models that generate certain observed ecological patterns, such as change in size distribution of individuals in a population over time, where large scale, aggregated models are not able to. The prospects and limitations of individual-based modeling are addressed.

Grime, J. Philip. 2001. Plant strategies, vegetation processes, and ecosystem properties 2nd edn. Chichester: Wiley.
Plant strategies (or functional types), based on the distinction between competitors, stress-tolerators, and ruderals (rapid colonizers), can be identified at different scales and used to predict properties of the community or ecosystem.

Jax, Kurt, Jones, Clive G., and Pickett, Steward T.A. 1998. The Self-Identity of Ecological Units. Oikos 82: 253-64.
Positioning an ecological unit, such as an ecosystem, along three axes—internal relationship, selected phenomena, component resolution—provides a basis for asking if it has remained the same over time, has changed, or no longer exists.

Kirchhoff, Thomas, Trepl, Ludwig, and Vicenzotti, Vera 2013. What is Landscape Ecology? An Analysis and Evaluation of Six Different Conceptions. Landscape Research 38 (1): 33-51.
Distinguishes six meanings and research agendas under the label “Landscape ecology,” especially in relation to the place of socio-cultural values.

Kolasa, Jurek and Pickett, Steward T. A. eds. 1991. Ecological heterogeneity New York: Springer-Verlag.
Collection of essays by ecologists addressing the definition, measurement, causes, and significance of heterogeneity in ecology.

O'Neill, R. V., et al. 1986. A Hierarchical Concept of the Ecosystem. Princeton NJ: Princeton University Press.
The key claims in this collection are that 1) at different spatial and temporal scales a system will be stable in its composition or homeorhetic in its processes (#1); 2) data analytic methods (#5) can expose the natural boundaries and aggregations; and 3) communities are probably not a natural or coherent subsystem of an ecosystem and so are an insufficient basis for ecological theory (#3), especially when the pathways cycling through decomposing organisms are omitted.

Taylor, Peter J. 2001. 'From natural selection to natural construction to disciplining unruly complexity: The challenge of integrating ecological dynamics into evolutionary theory'. In Thinking About Evolution: Historical, Philosophical and Political Perspectives. Edited by R. Singh, et al., 377-93. Cambridge: Cambridge University Press.
Although all evolution takes place in some ecological context, integrating the structure and dynamics of that context remains a neglected project within evolutionary theory. Nevertheless, the different approaches to theorizing ecological organization can still be broadly categorized in terms of the ways that evolutionary theory fits into them, whether or not this is made explicit.

7. Data analysis in relation to tight hypotheses, experimental manipulations, or long term observations
Allied to the particularistic impulse (#4) is an emphasis on testable hypotheses as the pathway to advance of ecology (Strong 1984, Peters 1991). For example, patterns of co-occurrence proposed in community ecology are compared with those produced by random sampling of species from the appropriately delimited species pool (Kelt and Brown 1999). Analysis of data from well-design experimental manipulations (Underwood 1997, Resetarits and Bernardo 1998) or long term observations (Ziebarth 2010, Fox 2012) may also yield reliable rules and generalizations. (A strong emphasis on hypothesis testing has been resisted from many angles; see #9.)

Fox, Jeremy. 'Zombie ideas in ecology: inferring causation from correlation in a density-dependent world', (updated December 27) <>, accessed 14 April 2014.
Given the dynamic feedback relations among variables, such as population size, correlations can be a “positively misleading… guide to causation.” “Milton Friedman's thermostat,” which illustrates an analogous error made in economics, is discussed.

Kelt, Douglas A. and Brown, James H. 1999. 'Community structure and assembly rules: Confronting conceptual and statistical issues with data on desert rodents'. In Ecological Assembly Rules: Perspectives, Advances, Retreats. Edited by Evan Weiher and Paul Keddy, 75-107. Cambridge: Cambridge University Press.
Examines extensive data on seed-eating rodents in southwestern North America to consider more general issues about how to conceptualize and analyze assembly rules or patterns of co-occurrence (in comparison with random models) and the relation of the patterns to underlying processes (#5). (Note the term assembly does not refer to data about trajectories of change over time [see #8].)

Peters, R. H. 1991. A Critique for Ecology. Cambridge: Cambridge University Press.
Argues that absent or poor tests of hypotheses have rendered ecology uninformative as a science and a guide to environmental problems.

Resetarits, W. J. and Bernardo, J. eds. 1998. Experimental Ecology: Issues and Perspectives New York: Oxford University Press.
A collection of essays by ecologists that address the range of experimental approaches, their place in ecology, and ways to improve the design as well as the connections on one hand with theory and the other hand with non-experimental situations.

Strong, D. R., et al. eds. 1984. Ecological Communities: Conceptual Issues and the Evidence Princeton, N.J.: Princeton University Press.
Chapters question many of community ecology's models (#3), advocating their rejection when their fit to data is no better than alternative "null" hypotheses or "random" models.

Tilman, David 1999. The ecological consequences of changes in biodiversity: A search for general principles. Ecology 80: 1455-74.
Provides an entry point to the revival since the mid-1990s of interest in explaining diversity and its contribution to ecosystem dynamics and subsequent debates about the the significance of results in this area. Experiments and models support the idea that stability, in the sense of constancy of numbers, increases with the number of species in mixtures of plants. (Note that productivity more than stability is the desired attribute that plant ecologists try to associate with diversity and that this research focuses on the single trophic level of plants, not the complexity of whole communities or ecosystems.)

Underwood, Anthony J. 1997. Experiments in Ecology: Their Logical Design and Interpretation Using Analysis of Variance. Cambridge: Cambridge University Press.
Despite the variability in space and time of ecological phenomena, informative experiments can be designed and subject to the statistical analysis of variance. (Strictly speaking, such results are local to or contingent on the configuration of other factors held experimentally or statistically constant for the experiment; Taylor 2005, 235 [under#8].)

Ziebarth, Nicolas L., Abbott, Karen C., and Ives, Anthony R. 2010. Weak population regulation in ecological time series. Ecology Letters 13: 21-31.
Uses sophisticated data analysis (model selection techniques to find best-fitting autoregressive-moving average models in order to derive two different metrics) to assess the strength of regulation of population sizes. Serves to remind ecological philosophers that methods of data analysis are needed to discriminate among competing models.

8. Embeddedness and problematic boundaries in space and time
The aspirations for identifying general principles about systems and communities (#3) have been undermined since the 1980s by a range of currents that pay attention to the lack of clear boundaries to any ecological entity or process and their embeddedness in a wider and longer context (see also #10). Embeddedness has potentially profound consequences for conceptualizing ecology. Whereas progress in the physical sciences depends greatly on controlled experiments, in which systems are isolated from their context, this model of science is not appropriate for understanding organisms embedded in a dynamic ecological context and responding to resources and hazards that are unevenly distributed across place and time. At the very least, analogies and conceptual borrowings drawn from work on well-bounded systems (#2, 3 and 6) warrant scrutiny, even when the behavior of those systems is governed by non-linear dynamics (Odenbaugh 2011).

[Departure from alphabetical order allows a narrative flow in the following annotations.]
DeAngelis, Donald L. and Waterhouse, Joyce C. 1987. Equilibrium and non-equilibrium concepts in ecological models. Ecological Monographs 57: 1-21.
In response to the complexity begets instability result (May 1973; see #3), a landscape view arose in ecological modeling, which holds that a community may persist in a landscape of interconnected patches even though the community is transient in each of the patches (DeAngelis and Waterhouse 1987).

Hastings, Alan and Harrison, Susan 1994. Metapopulation dynamics and genetics. Annual Review of Ecology and Systematics 25: 167-88.
Metapopulation theory, an actively explored variant of the landscape view (above), examines the persistence not of communities, but of populations (or phoretic associations of communities on carrier species) in such a landscape.

Nee, Sean 1990. Community construction. Trends in Ecology and Evolution 5: 337-40.
Another variant of the landscape view emerges from construction of model systems by addition and elimination of populations over time. This exploration shows that complexity can persist—at levels far greater than found in decomposable systems—even when any particular system is transient. In other words, investigations of ecological complexity should incorporate the construction and continuing species turnover, not only analysis of the stability and structure of the current configuration (see also Taylor 2005, p. 3-17 [below]).

Pickett, S. T. A. and White, P. S. eds. 1985. The Ecology of Natural Disturbance and Patch Dynamics Orlando, FL: Academic Press.
The modeling work above has parallels in field-based research. In patch dynamic studies, the scale and frequency of disturbances that create open patches is emphasized as much as species interactions in the periods between disturbances.

Gray, A.J., Crawley, M. J., and Edwards, P. J. eds. 1987. Colonization, Succession and Stability 26th Symposium of the British Ecological Society, Oxford: Blackwell.
Studies of succession and of the immigration and extinction dynamics for habitat patches pay attention to the particulars of species dispersal and the habitat being colonized, and how these determine successful colonization for different species.

Haila, Yrjö and Järvinen, O. 1990. 'Northern conifer forests and their bird species assemblages'. In Biogeography and Ecology of Forest Bird Communities. Edited by A. Keast, 61-85. The Hague: SPB Academic Publishing.
On a larger temporal and spatial scale biogeographic comparisons show that continental floras and faunas are not necessarily in equilibrium with the extant environmental conditions.

Wootton, J. Timothy 1994. The nature and consequences of indirect effects in ecological communities. Annual Review of Ecology and Systematics 25: 443-66.
Boundaries are made problematic by examining how effects mediated through the populations not immediately in focus or unrecognized upset the methodology of observing the direct interactions among a subset of populations and confound many principles, such as the competitive exclusion principle, derived on that basis (see also Taylor 2005, p. 17-30, 234-235).

Taylor, Peter J. 2005. Unruly Complexity: Ecology, Interpretation, Engagement. Chicago: University of Chicago Press.
Addresses unruly complexity, using the term to denote problematic boundaries and embeddedness in space and time, combined with attention to the heterogeneity of component entities or processes, thus highlighting the challenge identified under premise 3 in the Introduction to this bibliography. The cases examined, which open up from theoretical ecology to philosophy of science (and beyond—to social studies of science and critical pedagogy; #10), indicate how ecology has often mimicked the physical sciences in constructing—materially and conceptually—well-bounded systems, which have clearly defined boundaries, coherent internal dynamics, and simply mediated relations with their external context. Ecologists can then envisage themselves positioned outside the systems and seek generalizations and principles that afford a natural or economical reduction of complexity (#1). Ecologists who want, in contrast, to discipline unruly complexity without suppressing it recognize that control and generalization are difficult, no privileged standpoint exists, and ongoing assessment of typically changing situations is needed. Systems that are well bounded or have simple relations with their external context, when they are encountered, could be viewed not as simple situations, but as special cases whose existence requires explanation (#10). Running through ecological philosophy, in short, is a tension between unruliness and attempts to discipline it (p. 157-159).

9. Pragmatism, Partiality and Pluralism
A strong emphasis on hypothesis testing (#7) has been resisted by noting that, for example, theory generation draws on the many other faces of data (Haila 1988) and exploration of verbal and mathematical models has a valuable role in generating new concepts, framings, questions, and hypotheses (#3; Taylor 2005, p. 34-46). In other words, find ways to use models pragmatically or heuristically, all the time checking that they are not applied too far out of the domain in which they were derived and in which the applications are effective (Walters 1986, Reiners and Lockwood 2010). The exploratory use of models (#3) retains support, in part, because of an unstated implication that, if the different exploratory models could be combined, they would yield an understanding of ecological phenomena that could not be achieved through the construction of all-encompassing systems models (Taylor 2005, p. 41-42). For example, the idea that there is a limit to the similarity of co-existing species might be combined with the ideas that spatial heterogeneity or an intermediate level of disturbance promote diversity, and so on. The means of weaving together or synthesizing necessarily partial models, or heuristics, remains, however, to be articulated. Given that few ecologists can juggle more than a few heuristics, new approaches to conceptual work need to be developed that bring different types of ecologists into sustained interaction (Wondolleck and Yaffee 2000; see also #10). Two fall-back options are pluralism—accepting “that some phenomena require multiple accounts” (Kellert et al. 2006)—and unification of disparate theories under a set of broad principles making up general theory (Scheiner and Willig 2007).

Haila, Yrjö 1988. The multiple faces of ecological theory and data. Oikos 53: 408-11.
Theory generation draws not only on hypothesis testing, but also on initial category-generating generalizations from observations, comparisons, and analytic redescriptions.

Kellert, Stephen H., Longino, Helen E., and Waters, C. Kenneth eds. 2006. Scientific Pluralism Minneapolis: University of Minnesota Press.
Uses case studies from various fields of science (but not ecology) to propose that “scientists present various—sometimes even incompatible—models of the world” given that the complexity of the world is difficult to represent.

Reiners, William A. and Lockwood, Jeffrey A. 2010. Philosophical Foundations for the Practices of Ecology. Cambridge: Cambridge University Press.
In a systematic attempt to move beyond confusion and conflict about the status of ecological theories, the authors develop a philosophy of constrained perspectivism for ecology: “whatever perspective works within the bounds set by the client's needs and desires is adopted… constrained by the aspects of the external world relevant to the slice of nature that one has chosen to engage” (p. 195).

Scheiner, S. and Willig, M. 2007. A General Theory of Ecology. Theoretical Ecology 1: 21 – 28.
The numerous constituent theories and models of ecology fit under a general theory that has two parts, a description of the domain of ecology—“spatial and temporal patterns of
the distribution and abundance of organisms”—and a set of fundamental principles, namely, “heterogeneous distribution of organisms, interactions of organisms, contingency, environmental heterogeneity, finite and heterogeneous resources, the mortality of organisms, and the evolutionary cause of ecological properties” (p. 21). (The account points to many but not all of the impulses in this article; #1 and 2, on systemic properties and flows of energy and nutrients, are notably absent.)

Walters, C. 1986. Adaptive Management of Renewable Resources. New York: Macmillan.
Adaptive Environmental Management begins with a recognition that the dynamics of any ecological situation are not fully captured by any model or composite of models, especially because management practices produce continuing changes in those dynamics and make the ecological situation a moving target. Through carefully designed experiments in environmental management, a range of management practices, chosen on the basis of existing knowledge and model-based predictions, are implemented and lessons about the practices and models are drawn from the different outcomes.

Wondolleck, Julia M. and Yaffee, Steven L. 2000. Making Collaboration Work: Lessons from Innovation in Natural Resource Management. Washington, DC: Island Press.
Draws on many cases to illustrate how and why environmental planning and management has, especially since the 1990s, built in stakeholder collaboration, that is, explicit procedures for participation of representatives of community groups, government agencies, corporations, and private property owners.

10. Transversality and inversion
For some ecologists the growing emphasis since the 1980s on scale-crossing or transversal processes means that ecology needs to be reconceived as an historical science (Schluter and Ricklefs 1993). Ecologists, like epidemiologists, paleontologists, and historians, face the challenge of historical explanation (Brown et al. 2011, 251-282). That is, they have to assemble a composite of conditions sufficient for the subsequent outcomes to have followed and not some other—conditions that include considerable historical and geographical contingency (e.g., which organisms survived in pockets when Mt. St. Helens erupted) intersecting with structure that changes, is internally heterogeneous, and, because of overlapping scales of different species' activities, has problematic boundaries (#8). At the same time, historical explanation must not obscure the provisionality of such accounts in the face of competition from other plausibly sufficient accounts (#9).

Accounts that cut across and connect different strands or processes also invite inversion of the traditional orientation in science from simplicity to complexity. That is, instead of viewing ecological situations as the basis for understanding social-environmental processes, they might be viewed as special instances of those processes. That is, instead of basing ecological theory on situations in which human disturbance is minimal or constant, ecological concepts and methods could be informed by developments in social sciences. It may be helpful in this regard to follow a political ecological current of anthropological and geographical research emerging in the early 1990s might be noted that focuses on situated, transversal or intersecting socio-environmental processes (Taylor and García-Barrios 1995). Other kinds of inversion then follow: view natural science within the systematic study of social change (Resilience Alliance n.d.); conceptual work within scientific and technical practice in the field and laboratory (Schwarz 2014); scientific practice within construction of infrastructure and standards (Spellerberg 2005); and interpretation of science within engagement in scientific and social change (Haila and Levins 1992, Taylor 2005 [under #8]). Williams's (1980) fictional episodes of environmental history might inspire efforts to consider in the one picture changes, as well as tensions, in a human nature that traverses knowledge, labor, production, culture, and the environment.

Haila, Yrjö and Levins, Richard. 1992. Humanity and Nature: Ecology, Science and Society. London: Pluto.
Building from an analytic description of the practice of ecology in specific environments, this book rejects a politics of programmatic statements about ecology and society in favor of attention to “detailed, creative, innovative and collective efforts in specific historical, political and cultural situations” (p. xi).

Resilience_Alliance. <>, accessed 28 April 2014.
Extends Adaptive Environmental Management (Walters 1986 [under #9]) to analysis of the dynamical relationship between institutional behavior and ecological degradation, to participatory approaches or stakeholder collaboration (Wondolleck and Yaffee 2000 [under #9]) in policy and management towards support sustainable development.

Schluter, Dolph and Ricklefs, Richard. 1993. 'Species diversity: An introduction to the problem'. In Species Diversity in Ecological Communities. Edited by Richard Ricklefs and Dolph Schluter, 1-10. Chicago: University of Chicago Press.
Advocates going beyond the study of “small areas over short time spans in the belief that diversity is regulated by local ecological interactions” (see #3) to examine wider geographic patterns of diversity and the historical events that shape communities.

Schwarz, Astrid. 2014. Experiments in Practice, History and Philosophy of Technoscience, 2. London: Pickering and Chatto.
Using case studies from ecological research, provides historical perspective on the movement of the experiment from the closed and secured space of the laboratory towards the open spaces in the field sciences (#7) and more generally in urban and other social spaces.

Spellerberg, Ian F. 2005. Monitoring Ecological Change 2nd. edn. Cambridge: Cambridge University Press.
To claim that ecological communities are continuously changing (#8) or to build on that claim, there must be monitoring programs. Topics covered include the rationale, history, practical techniques, and evaluation of programs, as well as the rise of community-based monitoring or citizen science.

Taylor, Peter J. and García-Barrios, Raúl 1995. The social analysis of ecological change: From systems to intersecting processes. Social Science Information 34 (1): 5-30.
Reviews the post-World War II history of different conceptions of the object of socio-environmental research in terms of a contrast between systems (#2) and intersecting processes (#8). The latter concept means that environmental problems are analyzed in terms of intersecting economic, social and ecological processes, which operate across various spatial and temporal scales and are mutually implicated in the production of any outcome and in their own ongoing transformation. Accounts of soil erosion or collapse of fish stocks, for example, may tie together the local and regional ecological characteristics, local institutions of production and associated agro- or aqua-ecologies, the social differentiation in a given community and its social psychology of norms and reciprocal expectations, and national and international political economic changes (see also Taylor 2005, p. 159ff [under #8]).

Williams, Raymond. 1990. People of the Black Mountains: The Beginning. London: Palladin.
The fictional episodes of the long environmental history of what is now the Welsh-English borderlands resonates strongly with the project of analyzing socio-environmental change in terms of unequal groups of people making their livelihoods situated in transversal processes. Williams's work conveys not only that nature is a realm deeply shaped through a history of human political and economic transformations, but also that ideas about "nature" tell us much about people's ideas about the social order they favor.