The core tenet of the notion of sustainability is that humans are an integral part of the ecological systems which make up the biosphere. We cannot live apart from the biosphere but only as a part of it. Sustainable development, therefore, is development which fosters ecological integrity. Recognizing this, society has mandated, through various policy statements and legislation (the Great Lakes Water Quality Agreement, 1978, the Canada Park Service Act, 1988, the Montana Environmental Protection Act, 1992, Environment Canada's mission statement, 1992) the preservation, maintenance, promotion, protection, and restoration of ecological integrity. Given this context, state of the environment reporting (SOER) is about evaluating the current state of ecological integrity and the ways that our actions might influence it in the future.
This is well and good. But it does not help us unless we can operationalize the notion of integrity, and how to report on it. This is the quest that a number of us have been working on for the last fifteen years. This paper is a brief synopsis of what we have learnt. It is a meant to stimulate discussion and further reading of the literature. The essential issues to be covered are: a) what is meant by ecological integrity, b) how do we evaluate it and c) what are the implications for state of the environment reporting.
Complex Systems Thinking
A new understanding of ecosystems is emerging, and this understanding is the basis for discussing integrity. This new understanding comes from a group of thinkers who suggest that an "ecosystem approach" should be based on the notions of complex systems theory, the grandchild of von Bertalanffy's general systems theory. [2] The vision of an ecosystem, that the "new science" of complex systems theory provides, is quite different from that of a traditional Newtonian mechanistic world view. It is a vision of ecosystems as dynamic, constantly evolving systems which are not deterministic, but rather to a degree unpredictable. Change in such systems can be smooth or just as likely, sudden and surprising. Such systems can exhibit phases of rapid change, and even the extreme of catastrophic change is not abnormal. Left to their own devices, ecosystems are self-organizing, that is they will look after themselves.
Figure 1: Nested Holons (Hierarchy Theory)
The behaviour of a system (holon) is due to the interactions of its components (also holons) in the context of the wider system (another holon) it is part of. We can only understand systems from a hierarchical perspective, that is as nested holons. Generally five levels of description are required. The Huron Natural Area nested Holons are seen below:
There are a number of important lessons to be learnt from the study of complex systems. First, such systems can only be understood from a hierarchical perspective. [3] Neither a reductionist nor holistic approach is sufficient. One must look at the system as a whole and as something composed of subsystems and their components. (See Figure 1 and Table 1) One must also look at the system in the context of its being a subsystem of a bigger system which is in turn part of a wider environment. So to study a population in ecology without reference to the individuals that make it up, the community it belongs to, and the environment it lives in, is not sufficient. This is not to say that population ecology is not useful. It is just not sufficient to explain ecological phenomena. Self-organization of complex systems, including ecosystems, can only be understood in the context of what makes them up and the environment in which they must function.
Another property of these systems is that everything is connected (at least weakly) to everything else. But no scientist can look at everything at once. So any analyst must make decisions about what to include and what to leave out of the system to be studied. Scale and extent and the hierarchical units of study must be selected. These decisions, while done in a systematic and consistent way, are necessarily subjective, reflecting the viewpoint of the analyst about which connections are important to the study at hand, and which can be ignored. So, because of their very nature, the notion of a pristine objective scientific observer is not applicable to the study of self-organizing systems. This has significant implications for ecosystem classification and boundary selection.
Figure 2: A simple example of catastrophes in ecology
As the herbivore population increases, the vegetation decreases (more is eaten). The system moves along the upper solid (blue) line (attractor). Eventually a point (X) is reached where the vegetation crashes (the system becomes unstable) because of overgrazing. As the vegetation regrows the herbivore population drops off sharply (the lower (green) solid line, another attractor) until a second point (Y) is reached (the system becomes unstable again) and a vegetation bloom occurs. The vegetation crash and bloom are catastrophes in the mathematical sense of the word. X and Y are known as critical thresholds.
Complex systems exhibit emergent dynamic behaviours. Catastrophe theory [4] describes one class of surprising dynamics of these systems. It predicts that systems will undergo dramatic, sudden changes in a discontinuous way. For example, in studies of acidifying lakes, investigators noticed in the 1970s that even in cases where sensitive water bodies were subject to a continuing rain of sulphates and nitrates from the atmosphere, the water pH did not change very much for quite a long time. But then, rather suddenly, the pH would drop sharply. The explanation is that until the buffering capacity of a lake is used up, the pH changes little. A contributing factor is spring snow melt, which causes a sudden flush of sulphates and nitrates stored over the winter. The example often cited is Big Moose Lake, N.Y., where pH remained almost constant in the period 1900-1960, and then fell precipitously. [5]
Another example, which gives serious pause for thought, is that there is recent evidence for a "flip-flop" end to the last Ice Age in Greenland, with "a double shift from glacial to interglacial conditions over an astonishingly quick 3-5 years" about 18,000 years ago ; the temperature changed by about 7[[ring]] C during these shifts. [6]
Furthermore, at the point where a system undergoes a "catastrophic" change, there may be several possible distinct changes which can occur. Which one will actually happen is not always predictable. The insight from catastrophe theory is that the world is not a place where change always happens in a continuous and deterministic way.
The choice of the name, catastrophe theory, is unfortunate as it denotes abnormal nasty events. What we have come to realize is that such events are normal and necessary for the continued smooth functioning of many systems. For example our heartbeat is a catastrophic event, as is the emptying of our bladder. They are discontinuous events which occur suddenly and are necessary for our continued survival. Over the last decade students of ecosystems have come to realize that such behaviour is not only normal for ecosystems, but necessary for their well being (for example fire and pest outbreaks in forested ecosystems). [7]
That ecosystems exhibit catastrophic behaviour has several important implications:
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Classical ideas of ecosystem development are based on succession, which ultimately leads to a steady-state condition: climax vegetation. Holling [8] , building on the ecological insight gained from catastrophe theory, has extended this conceptual framework of ecosystem development in two ways :
1. Succession is only one phase of the figure-eight or four-box pattern.
2. Ecosystems are spatially and temporally lumpy; uniform ecosystems exist only in monocultures. Patchiness is an essential characteristic of an ecosystem that has integrity.
These two ideas are connected in the following way. Succession (initially, a relatively fast process) is the upward loop in figure 3 extending from Exploitation to Conservation (the climax state). In this latter "mature" state, most of the nutrients and energy are locked up in the biomass, and the system gradually becomes brittle. Key structural parts become risk prone, waiting for an accident to happen through fire, wind-storms, pests and senescence (the downward segment in the figure, i.e., from Conservation to Release). This latter relatively fast process generally occurs in patches, releasing nutrients and energy locally and ultimately permitting the cycle to move on in the figure eight from Release to Reorganization. Finally, the loop is closed through Exploitation (succession) back to Conservation. Lumpiness is an essential part of the figure-eight model, and indeed of nature itself. The processes take place over a range of space and intergenerational time scales (from days and mm. to centuries and thousands of square Km.). Understanding ecological integrity requires understanding these figure eight patterns and the associated lumpiness.
Figure 3: The Holling "figure-eight" model of an ecosystem
The cycle reflects changes in two attributes: (1) y-axis; the amount of accumulated capital (nutrients, carbon) stored in variables that are the dominant variables at the moment; and (2), the x-axis; the degree of connectedness among variables. The exit from the cycle at the left of the figure indicates the stage where a flip into a greatly modified ecosystem is most likely. It is at this juncture that the ecosystem's information library (stored mainly in the species and their genes) steers it around the figure eight.
Another characteristic of an ecosystem with strong integrity is the existence of an information library, mainly the species and their genes. Genes contain the historical record of previously successful self-organization. They constraining the self-organization of an ecosystem to those options which have a high probability of success (Kay, 1984). Referring to figure 3, the system information library is of most importance at the point of exit from the figure eight to the left of the figure. This is where a flip into a greatly modified ecosystem is most likely. This point, the transition to the exploitation phase, is when the ecosystem is, in effect, reset. What the ecosystem is reset to, is a function of the environmental context and the information available at the time of reset. This is the moment when biodiversity is most important.
Holling has extended these ideas even further. Recognizing that there are nested cycles of both time and space scales involved in ecosystem development, Holling argues that for each scale, only small numbers of processes and species predominate. Thus a reasonable picture of the functioning of the system at that level can be obtained by concentrating on these most important processes and species. However, interactions between processes operating at different levels (i.e., different time and space scales) do occur and furthermore are non-linear, with the possibility of flip-flops. Thus the behaviour of the system at higher or lower levels of aggregation cannot be easily ascertained from that at the time and/or space scales being investigated. Holling has supported these ideas with a cross-scale analysis of animal body mass, which shows discontinuities across landscapes.
Holling's ideas reinforce the notion of ecosystems as dynamic structures that:
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Figure 4: Example of Multiple attractors
Benthic vs. Pelagic shallow lake ecosystems
[9]Two different states for shallow lakes have been identified. In the benthic state, a high water clarity bottom vegetation ecosystem exists. As nutrient loading increases the turbidity in the water, the ecosystem hits a catastrophe threshold and flips into a hypertrophic, turbid, phytoplankton pelagic ecosystem. Lakes which flip between these states on a regular basis have been found. (Lake Ontario appears to be currently in the midst of such a flip, from pelagic to benthic.) In some lakes, the spring run off (nutrient loading) determines which state the ecosystem will be in for the summer. This is an example of a bifurcation in an ecosystem's behaviour as it hits the reset point for the seasonal figure eight.
Another set of insights into complex systems comes from self-organization theory and particularly, nonequilibrium thermodynamics. Prigogine [10] showed that spontaneous coherent behaviour and organization (i.e. tornadoes, vortices in fluids, lasers) can occur and is completely consistent with thermodynamics. The key to understanding such phenomena is to realize that these are open systems with a flow of high quality energy. In these circumstances, coherent behaviour appears in systems almost magically. Prigogine showed that this occurs because the system reaches a catastrophe threshold and flips into a new coherent behavioral state.
In examining the energetics of open systems Kay and Schneider [11] have taken Prigogine's work one step further. They are interested in open systems with high quality energy pumped into them and their consequent movement away from equilibrium. Systems resist this movement away from equilibrium. If new kinetic and dynamic pathways for dissipation are available, the open system will respond with the spontaneous emergence of organized behavior that uses high quality energy to maintain its structure, and dissipates high quality energy in its movement away from equilibrium. The more high quality energy pumped into a system the more organization can emerge to dissipate the energy. Again, the emergence of organized behavior, (and even life) in systems, is now expected according to modern thermodynamics. This self-organization is characterized by abrupt changes which represent a new set of interactions and activities by components and the whole system. The form of expression this self-organization takes is not predictable. This is because the very process of self-organization is via catastrophic change (in the catastrophe theory sense) and flips into new regimes.
The vortex which forms in a bathtub, is an example of this behaviour. This type of vortex appears almost by magic. It drains the water more quickly. The more water there is to begin with (bigger gradient, more exergy) the faster the vortex drains the water. Such self-organizing phenomena (like life) is no longer considered an enigma in the sense that it runs counter to the laws of thermodynamics. Everything isn't running down, rather the spontaneous emergence of organized systems is to be expected. Furthermore these systems tend to get better and better at grabbing resources and utilizing them to build more structure.
Figure 5: Life as a Self-organizing System
As living systems develop, the direction of this development improves their ability to survive and utilize energy. Consider the growth of a chicken embryo as in the following graph. The point is that as the embryo develops, it use more energy (W), that is it gets better at extracting energy from its fixed source, the yoke. Notice that there are three distinct phases which represent the emergence of different capabilities for utilizing the energy. (Data from Briedis and Seagrave 1984.)
We see the same phenomena in ecosystems. As ecosystems develop, that is become better organized, they also become more effective at capturing solar energy and extracting the exergy from it. This can be measured by flying over a terrestrial ecosystem and measuring its surface temperature. The surface temperature measures the quality of the energy, after the ecosystem has used it and is finished with it. The cooler the temperature, the more thoroughly the ecosystem has utilized the energy. This can also be used to measure the effectiveness with which the ecosystem utilizes the energy.
Using data collected by Luvall and Holbo for the H. J. Andrews experimental forest (temperate rainforest, Douglas Fir) we can see this phenomena. The following data was collected and is organized from least developed to most developed ecosystem. It clearly demonstrates that we can measure ecosystem organization using energy balance techniques and that more developed ecosystems are better at utilizing the available energy. (More details can be found in Schneider and Kay, 1994b)
Ecosystems as self-organizing entities
The theory of non-equilibrium thermodynamics suggests that the self-organization process in ecosystems proceeds in a way that: a) captures more resources (exergy and material); b) makes more effective use of the resources; c) builds more structure; d) enhances survivability. These seem to be the basic rules of the game (self-organization) in ecosystems.Systems that exhibit self-organization exist in an energetic window where they get enough energy, but not too much. If the they do not get sufficient energy of high enough quality (beyond a minimum threshold level), organized structures cannot be supported and self-organization does not occur. If too much energy is supplied, chaos ensues in the system, as the energy overwhelms the dissipative ability of the organized structures and they fall apart. So self-organizing systems exist in a middle ground of enough, but not too much. [12] Furthermore, these systems do not maximize or minimize their functioning. Rather their functioning represents an optimum, a trade-off among all the forces acting on them. If there is too much development of any one type of structure, the system becomes overextended and brittle. If a structure is not sufficiently developed to take full advantage of the available energy and resources, then some other more optimal (i.e. better adapted) structure will displace it. Self-organization in ecosystems is a dynamic ongoing balancing act striving for the middle ground. The only static equilibrium stable state for living systems is death.
Management goals that involve maintaining some fixed state in an ecosystem or maximizing some function (biomass, productivity, number of species) or minimizing (pest outbreak, fire) will always lead to disaster no matter how well meaning they are. We must instead recognize that ecosystems represent a balance, an optimum point of operation, and this balancing is constantly changing to suit a changing environment. Management must focus on facilitating and directing change, not attaining and maintaining some fixed state for all time. We must manage our behaviour so that it enhances the organization of the ecosystems which we are all part of.
Understanding ecosystems as self-organizing entities requires a hierarchical perspective with careful attention to scale and extent. We must examine the spatial, temporal, thermodynamic and information aspects (dynamics) of these systems. This must be done in the context of behaviour which is both emergent and catastrophic. In other words we must recognize that ecosystems are dynamic, not deterministic, have a degree of unpredictability and will exhibit phases of rapid change.
But this is not to say that ecosystem behaviour is chaotic or random and haphazard. On the contrary, ecosystem behaviour and development is like a large musical piece such as a symphony, which is also dynamic and not predictable and yet has a sense of flow, of connection between what has played and what is still to play, the repetition of recognizable themes and a general sense of orderly progression. In pieces such as symphonies or suites we know the stages (allegro, adagio, etc.) that the piece will progress through, even though we don't know the details of the piece. The same is true of ecosystems, some behave in a very ordered way as does a Baroque suite, and others are full of improvisation as in modern jazz. And yet we know the difference between music and random collections of noise. Our challenge is to understand the rules of composition and the limitations and directions they place on the organization process, as well as what makes for the ecological equivalent of a musical masterpiece which stands up to the test of time.
Ecosystem Integrity
Our sense of the ecosystem as a whole, that is its Integrity, has to do with its ability to maintain its organization and to continue its process of self-organization. For an ecosystem, integrity encompasses three major ecosystem organizational facets. Ecosystem health, the ability to maintain normal operations under normal environmental conditions, is the first requisite for ecosystem integrity. But it alone is not sufficient. To have integrity, an ecosystem must also be able to cope with changes (which can be catastrophic) in environmental conditions; that is, it must be able to cope with stress. As well, an ecosystem which has integrity, must be able to continue the process of self-organization on an ongoing basis. It must be able to continue to evolve, develop, and proceed with the birth, growth, death and renewal cycle (i.e. Holling's figure eight). It is these latter two facets of ecosystem integrity that differentiate it from the notion of ecosystem health.
Three aspects of Ecosystem Integrity:
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- The system can continue to operate as before, even though its operations may be initially and temporarily unsettled. (Figure 6)
- The system can operate at a different level using the same structures it
originally had (Figure 7).
- Some new structures can emerge in the system that replace or augment
existing structures (Figure 8)
- A new ecosystem, made up of quite different structures, can emerge.
(Figure 9)
- The final, and very rare possibility, is that the ecosystem can collapse completely and no regeneration occurs.
Figure 6: The process of self-organization in ecosystems
Development is characterized by phases of rapid organization to a
steady-state level followed by a period during which the system maintains
itself at the new steady state. The organization of the system is not a smooth process but rather proceeds in spurts. These spurts are a sudden acceleration in the change in the state of the system. The overall direction of development is one which satisfies the necessities of increasing energy degradation while enhancing survivability. An ecosystem develops along a Thermodynamic Branch (a path in state space) until it reaches an Optimum Operating Point. This is a point in state space where the self-organizing forces are balanced by the disorganizing forces of external environmental change. (This is a simplification of the more complex process described by Holling's figure
eight.)
Figure 7: Simple stress response
The environmental change causes the ecosystem to move from its original optimum operating point (1) to a new optimum operating point (2). An example of this would be a stress which causes an ecosystem to return to an earlier successional stage. The practice of spraying the end product of the secondary treatment of municipal waste water on terrestrial ecosystems is such a stress. Pine forests subjected to such spraying are shifted back to an old field community (i.e. the developmental stage prior to a forest)
Figure 8: Reorganization
In response to changing environmental conditions the system moves away from the original optimum operating point (1) through a bifurcation point (2) and onto a new path and then to a new optimum operating point (3). An example of this case is the switch from a white spruce community to a black spruce community when the former is subjected to a sharp reduction in nutrient availability. In these forested taiga ecosystems, black spruce are better suited to low nutrient situations and once established tend to exclude white spruce by maintaining the low nutrient situation. The white spruce is not able to reassert itself once displaced.
Figure 9: A flip to a new attractor
The environmental change drives the ecosystem from its original optimum operating point (1) through a catastrophe threshold (2) to a new thermodynamic branch at (3) and eventually to a new optimum operating point (4). An example is the elimination of fish in lakes caused by acid rain. Another example of this is the switch between pelagic and benthic ecosystems in shallow lakes as discussed earlier.
This enumeration of possible ecosystem responses to environmental change is far richer than the simple classical notion, which holds that stress temporarily displaces an ecosystem from its climax community, to which it eventually returns. In fact, an ecosystem has no inherent single preferred state for which it should be managed.
While this list identifies the ways in which an ecosystem might re-organize in the face of environmental change, it does not indicate which re-organization constitutes a loss of integrity. It could be argued (and often is) that any environmental change that permanently alters the normal operations of an ecosystem affects its integrity. Ecosystem integrity would then be defined as the ability to absorb environmental change without any permanent ecosystem change. Thus the final three distinct ecosystem responses, in the list, would constitute a loss of integrity, even though all are responses in which the ecosystem reorganizes itself to mitigate the environmental change. However, the reorganized ecosystem is usually just as healthy as the original, even though it may be different. There is no scientific reason that an existing ecosystem should be the only one to have integrity in a situation, just because of its primacy.
At the other extreme, it could also be argued that any ecosystem that can maintain itself without collapsing has integrity. Utter collapses have been rare, desertification being one of the few examples. This definition would encompass almost all ecosystems, including ones whose organization has changed radically in response to major stress.
Neither of these definitions of integrity is operationally useful. The definition which accepts only temporary change is too restrictive in most situations, and reflects a desire to preserve the world as it is currently. This denies the fundamental dynamic nature of ecosystems and leads to disastrous mismanagement (e.g. the complete suppression of forest fires, which eventually results in catastrophic conflagrations). But the latter definition, which accepts all responses except collapse, does not help managers because it restricts loss of integrity to a situation that rarely occurs and that is clearly undesirable. Hence this definition would be trivial.
In between these two extremes of definition lies a third option, which holds that some changes in ecosystems are undesirable, and therefore represent a loss of integrity. This option promises to be the most useful but it embraces many possibilities and requires difficult choices. In particular it requires the value-laden selection of criteria for determining which changes are desirable and which are not. The science of ecology can, in principle, inform us about the kind of ecosystem response or reorganization to expect in a given situation. It does not provide us with a scientific basis for deciding that one change is better than another, except possibly in the two extreme cases just discussed.
The insight into ecological integrity gained from complex systems theory is that the physical and biological sciences can describe and, even to a limited extent, predict human-induced changes in the biosphere, but they alone cannot determine which changes are acceptable. Ultimately, any evaluation of the ecological acceptability of a human activity, will depend on value judgments about whether the resulting changes in the affected ecosystem are acceptable to the human participants.
Evaluating Integrity and State of the Environment Reporting
We have less than ten years experience at undertaking evaluations of ecological integrity. There are many problems still to be worked out and many issues, both theoretical and methodological that require further research. So it is not yet possible to present a coherent body of knowledge about ecological integrity and hence methodology for State of the Environment Reporting. Several efforts have been made to pull together what we do know [14] and I recommend these for further exploration. In Appendix 2 I have summarized the concerns of a number of my colleagues, that have arisen from experience with State of the Environment Reporting.In the final analysis, to define ecological integrity is to define a set of ecological characteristics to be monitored for change beyond specific values. To operationalize the notion of integrity requires the development of a monitoring framework and its associated measures and indicators. There are three distinct issues to be dealt with in developing a monitoring scheme for ecological integrity. First the changes in organization, to be associated with changes in ecological integrity, must be identified. Then comes the scientific and technical problem of how to quantify these changes. What needs to be measured and how is it best done? These are scientific and technical issues we are all struggling with. Once measurements have been decided upon, the issue of evaluation becomes paramount. For what values of the measures will integrity be deemed to have been lost? Who will make this decision and who will act on it? To answer the first and the last of these three questions, requires that the understanding of physical and biological scientists be combined with the concerns of society as voiced by elected officials, policy makers, public interest groups, and others. Only when this combination occurs, will it be reasonable to expect ecological integrity to result from our stewardship of the biosphere.
The process of developing a monitoring framework must start by identifying the users of the information gained from the monitoring. What information do they need, and in what form must it be presented to be usable? With this established, a system identification exercise is conducted so as to resolve such issues as what hierarchical levels will be focused on, what temporal and spatial scales will be covered, and what processes need to be monitored.
Measures for several different hierarchical levels and scales will be needed (Shackell & Freedman, King). The measures will be rooted in the bioregion and social issues in question (Keddy et al). Also, measures drawn from a number of different theoretical perspectives (e.g. landscape ecology, self-organization theory, population biology, etc.) will be required for a complete picture (Karr). Some measures will monitor the general condition of the ecosystem and its environment. Others will focus on specific known threats and the system's response to these threats. (Marshall et al, Woodley). Some will assess damage while others will serve as early warning alarms.
Clearly a variety of measures are necessary to adequately monitor ecological integrity. King points out that measures must not be over-integrated as this will result in the loss of valuable information. Steedman and Haider, and Keddy et al suggest methods for developing monitoring schemes and indicators. Woodley, Shackell and Freedman, Marshall et al., and Munn all discuss criteria for monitoring programs and indicators of ecological integrity. The work of Scheifer et al (1988) and Harris et al (1987) also provide guidelines for selecting measures. Recently the International Joint Commission has published a framework for developing indicators of ecosystem health for the Great Lakes Region (International Joint Commission, 1991).
Having completed the process of identifying the changes to be monitored and the measure thereof, we still face formidable technical and scientific problems. Ecology is still a young science and many methodological issues remain to be resolved. Karr points out, for example, that there is a tendency to take averages as the signal and variability in what is measured as noise. Both he and Woodley point out that the variability is often, in fact, the signal. But how to measure this?
The next step is development of evaluation criteria. Steedman and Haider propose a process for developing criteria in general. A main problem in this respect is the lack of baseline data for comparison purposes. In this regard, Rubec and Marshall have identified three priorities for Canada:
- A first order of business must be integrating and synthesizing human activity and ecoregional information across Canada.
- Development of national measures of ecosystem health and integrity will also require the creation of a national network of stable, secured and intercomparable benchmark reference sites with at least one such site in all ecoregions.
- We must ensure that existing interdisciplinary monitoring sites and networks are maintained (such as the Experimental Lakes Area, and the Dorset, Turkey Lakes, Lac Laflamme and Kejimkujik Watersheds developed in the national acid rain program) to provide the long-term perspective essential to monitoring and uniquely available through these areas.
Examples of monitoring schemes and specific indicators of integrity are presented in our book [15] ; for bottom sediments (Reynoldson and Zarrell), for wetlands (Keddy et al.), for the Atlantic ecozone (Schackell and Freeman), for stream ecosystems (Karr), and for national parks (Woodley). Kay and Schneider (1993) discusses measures of ecosystem integrity based on foodweb analysis. All of these discussions of ecological integrity are rooted in a specific context.
Complex systems theory and traditional science can help us describe and understand changes in ecological systems. Systems theory can help us focus on issues of importance, vis a vis integrity. However they alone cannot determine which ecological changes constitute a loss of integrity. When we define ecological integrity we are undertaking to integrate everything we know about an ecological system and where we want it to be. This integration, to be complete, must include the sum total of human preferences and concerns about the system. We must find paths for ecosystem development which assure our species survival both in the short and long term. Such paths will balance the needs of other species with our own, so as to maintain a biosphere in which humans have a sustainable niche.
Working in consultation with State of the Environment Reporting, Environment Canada we are developing a framework for doing just this. The first step is an evaluation of ecological integrity using the steps outlined in appendix 1. An example of the application of this methodology to a relatively simple state of the environment reporting exercise is contained in Appendix 3 "The Huron Natural Area: An ecosystem approach". Figure 10 contains a different representation of the same methodology with the addition of explicit decision making and management components. This figure clearly differentiates between four distinct phases in the process
Figure 10: The Ecosystem Approach: The protocol
The top box is the system study, which involves identifying the ecosystem, its important attributes and its behaviour vis a vis complex systems theory. The box on the middle right is about the process of establishing our vision for the ecosystem. The diamond is about bringing together our vision with what is ecologically possible and defining what will constitute integrity for the ecosystem. The bottom box is about ecosystem management, that is managing our and external influences on the ecosystem so that the appropriate form of self-organization is manifested. (Note that since this was written, this protocol has been developed in considerably more detail, see for example my work with M. Boyle.)
The top box which is about undertaking a system study to understand the current status of the ecosystem. This analysis explicitly describes the ecosystem using the notions of complex system thinking. As such it is a marriage of systems identification and scientific analysis. The former involves identifying the nested holons to be studied by bringing together all the stakeholders and experts in order to define the proper (not correct) focus (i.e. scale, extent, hierarchy etc.) for the study. This exercise can be facilitated using a methodology such as Checkland's Soft Systems Approach. The latter involves understanding the ecosystem in terms of the attractors available to it, its behaviour about these attractors (Holling's figure eight for example) and particularly what is likely to precipitate flips between the attractors. Particular attention needs to be paid to the feedbacks, that is the self-organizing processes, which are operating to promote the attractors. This activity represents an effort to integrate the best scientific understanding we have about the ecosystem. Such an understanding depends on the availability of historical and current information about the ecosystem under study. Without adequate long term ecosystem research and monitoring, as discussed above, the ability to successfully complete this phase is compromised.
The box on the right is the input from the political process in society. In our work we have answered this question by drawing on vision statements and policy documents for the area being examined. [16]
The diamond represents the coming together of what has been identified as being possible with what we desire and need. This is the point where science and socio-political issues are brought together to define what constitutes a loss of ecological integrity. This is the business of post-normal science. [17] Again this is a political process that involves real world tradeoffs. In State of the Environment Reporting this step consists of identifying inconsistencies between what society wants to do and what is ecologically possible.
The bottom box is about governance, momitoring, and ecological management, that is management of our influence on ecosystems. Ecological management is about identifying the influences we have on the feedbacks which promote the ecosystem's attractors. We must decide which feedback and self-organizing processes to encourage and which to discourage by altering our influence as is appropriate.
A simple example is in order. In the Huron Natural Area (See Appendix 3 "The Huron Natural Area: An ecosystem approach") a closed soft maple swamp (current attractor) in a wetland community could be pulled toward different attractors based on the amount and duration of the flows of water. Drying events such as an extended drought could pull the system toward an upland forest community or grassland (other attractors) with associated vegetation structure. If there are extended periods of flooding causing high water levels, the attractor would be that of a marsh ecosystem. This is because red and silver maple are tolerant to flooded conditions within 30% to 40% of the growing season. If flooding events are greater than this threshold, the forest trees will die, giving way to more water tolerant herbaceous marsh vegetation. (The feedback mechanism which maintains the swamp attractor is evapotranspiration (i.e. water pumping) by the trees. Too much water overwhelms the pumping capability of the trees and not enough shuts it down.)
A subdivision is about to built adjacent to the swamp. This could change the runoff into the swamp. (This is the human influence.) However we wish to maintain the swamp. So the question becomes how much can the runoff change before the swamp flips into the domain of one of the other attractors? It turns out that we don't know the current runoffs, or what changes can be allowed and would take several years of data collection to determine this. So the only way to be sure to maintain the integrity of the swamp is for the developer to build in a way which does not alter the drainage patterns into the swamp.
In appendix 3 there is a discussion of how to apply these ideas to a real site. It is incomplete as we are still learning how to execute the methodology. However we have learnt several lessons worth highlighting. The nested holon approach allowed us to systematically (using the ABCE method) identify the influences which were likely to affect the ecosystem's integrity. This guided our choice of what information to collect and the geographical extent which must be covered. It also allowed us to identify the self-organizing characteristics of the ecosystem that needed to be investigated. In essence this provided us with the framework for state of the environment reporting for this site. Having said this, it did, however, take us much work to establish the nested holons and information required for each holon, and we are only starting to collect the necessary data This approach also explicitly connects the ecosystem to the outside world, thus it is being analysed in context. The discussion of attractors makes it explicit for decision makers, that they must decide what they want on the site, and that this decision must be made in the context of adjacent human use of the land. (For example, the swamp or marsh or forest of the previous example.) Having said this, it must be noted that there is a dearth of information about what the potential attractors are and what the thresholds for flips are, as the science of ecology has only just begun to ask these questions. The study of ecosystem as complex systems is just beginning.
In closing then, we must always remember that left to their own devices, living systems are self-organizing, that is they will look after themselves. (A damaged ecosystem, left to its own devices, has the capability to regenerate, if it has access to the information required for renewal, that is biodiversity, and if the context for the information to be used, that is the bio-physical environment, has not been so altered as to make the information meaningless.) The challenge facing the practice of environmental management is to learn how to work with these self-organizing processes in a way which allows us to meet our species needs, while still preserving the integrity of ecosystems, that is to say the integrity of the self-organizing processes. Put in a more positive way, the challenge is to manage human activities so as to enhance the natural developmental processes ongoing in ecosystems while doing those things we wish to do. It is not ecosystems that need management, it is our use of the landscape. But we can have our cake and eat it too. By managing our activities to enhance ecosystem self-organization, we will enhance the free benefits we receive from the biosphere. It is a question of understanding the self-organizing processes in ecosystems and then managing our actions so they interact synergisticly with these self-organization processes. Only by acknowledging that the essence of ecosystems is self-organization, and our responsibility for maintaining these self-organizing process, will we assure our species a sustainable niche in the biosphere. And this therefore is the focus of State of the Environment Reporting, evaluating the integrity of ecosystems as self-organizing entities, and the state of our influence, both positive and negative, on this integrity.
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Appendix 1
The
Ecosystem Approach to evaluating ecological integrity
A. Define the ecosystem
- Hierarchy (The vertical perspective, what is a part of what?)
- Define the Nested Holons (nested living systems); this defines the contextual relationships.
- Scale and Extent (the horizontal perspective, where do things begin and end?)
- What are the boundaries of observation?
- What are the processes which define the whole?
- What are the boundaries of the ecosystem, the holon of focus?
- What are the processes which define the whole?
- Structure
- The vertical and horizontal connections between holons
- Non-Linear Models: The synergistic relationships, the cycles, the feedback loops, virtual worlds.
- What are the attractors?
- In what direction will the ecosystem tend to develop? What are its propensities?
(Self-organization theory of dissipative structures helps answer this.) - What is the behaviour of the ecosystem about the attractors?
- (Homeostatic, Stable, Figure eight, Unstable but persists, chaotic?)
- Are there bifurcation points?
- What are the potential flips between attractors?
- What triggers the flips?
- How can we monitor for them?
- How can we monitor for them?
- What is the interplay of energy, exergy, information and environmental conditions (in space and time) which shapes the ecosystem?
- Think carefully about the Figure eight, their scale and extent, the nested holons and their interactions and connections, the information available to the ecosystem, and the environmental conditions it must live with.
(Ecological history and non-equilibrium thermodynamics help answer this) - (What states of ecosystem organization are acceptable to us?)
- What are the ecological processes (at each of the nested levels) we value and/or need?
- How do we identify these?
- How do we measure the status of these processes?
- (Notice that this takes us back to step A above)
- Which attractors represent unacceptable ecosystem conditions?
- What are the ecological processes (at each of the nested levels) we value and/or need?
- What are the external forces which could effect the organizational status
of the system?
- Use the nested ABCE methodology to identify the external influences on the organization of the ecosystem. (stress-response ecology)
- What are the thresholds of flips to the unacceptable attractors? (states of ecosystem organization)
- How do we monitor to make sure these thresholds are not crossed?
- Use the nested ABCE methodology to identify the external influences on the organization of the ecosystem. (stress-response ecology)
- How do we mitigate known threats?
- How do we promote positive influences? (For example; fire in a prairie)
- How do we monitor the ecosystem so as to detect changes due to previously unidentified external influences?
- How do we promote positive influences? (For example; fire in a prairie)
The attractors (organizational states) and their domains:
C. How do we evaluate Integrity for this ecosystem?
D. Is this integrity threatened?
E. How do we maintain integrity in this system?
F. How to deal with Emergent Complexity..........
When all is said and done, our ability to predict is severely limited. Unexpected events and trends will occur. Surprise will happen, complexity will emerge. We must therefore rely on anticipatory and adaptive management.
Always remember "The system imbedded in another system, imbedded in another system, imbedded in another system, ........." and the challenge of sustaining a dynamic, changing, evolving, self-organizing, self-entailing, adaptive ecosystem.
Appendix 2
Some concerns of State of the Environment Reporting practitioners. [18]
The need for an arms-length agencyThe group which does state of the environment reporting needs to be at arms length and completely independent from management and decision making bodies. This is the same concept as is applied to financial audits. Agencies responsible for environmental and ecological management should not be expected to report on themselves.
Defining regions for study.
Most state of the environment reporting pick one class of criteria for dividing up the geographical area into manageable regions. (For example soil types or watersheds or political boundaries.) There is a consensus emerging that boundaries must be chosen through an integration of different kinds of criteria (watershed, terrestrial ecozones, geomorphology, airshed, socio-economic, political) so that the resulting study regions are sufficiently homogeneous that useful generalizations can be made.
The need for a wide suite of measures and indicators.
State of the environment reporting is about a complex set of problems. To distill these problems down to a handful of numbers is to loose the richness and detail which should be a part of state of the environment reporting. There is not an environmental equivalent of GNP.
Relate economic and environmental indicators
State of the environment reporting should makes use of economic indicators and explicitly relate them to environmental indicators. Only when this is done can we have a meaningful discussion of sustainability
Establish the needs of the users of the report.
State of the environment reporting should be done in the context of the end users of the information. The report cannot be all things to all people. What action will the report be used as the basis for? This requires consultation with potential users at the beginning of the process. For example, decisions makers and managers have been neglected in that the information has not been made useful and relevant to the action oriented decisions they must make.
Using hyper-text may allow the information to be packaged in different ways for different users.
The cost incurred by users to obtain the report should not be such as to limit accessibility.
Report format and frequency
The days of generating paper state of the environment reports are probably numbered. A hyper-text format is more appropriate than a linear paper format. The report should be available on-line.
There is also a sense that re-doing the report for the entire geographical region at fixed intervals is not a productive use of resources. Rather, for each region, a suitable time period for re-visiting the area should be established. State of the environment reporting then becomes an on-going exercise which, at any given time, is focusing on specific case studies in specific regions. However there should be annual or bi-annual reports on these activities made to the appropriate political body. (In Canada for example, to parliament much as the auditor-general's report is tabled.)
Focus on monitoring not report writing
State of the environment reporting as an activity tends to become more focused on report production than on monitoring and evaluation.
Data accessibility
In order to properly carry out state of the environment reporting access to all relevant data is required. The process is often hampered by an unwillingness of one agency to let another agency look at its data. The notion of state of the environment reporting having the powers and independence of an auditor would help rectify this situation.
There is also a need for access to privately held information and this means sufficient budget to access libraries and purchase necessary databases.
Need for long term monitoring and research sites.
State of the environment reporting requires baseline data. Baseline data can only come from long term monitoring of representative ecosystems. This in turn requires long term funding for a network of research sites such as the LTERM sites in the United States.
General concerns about data
Data quality and gaps in the data are important considerations which are often overlooked.
Maintenance of quality data sets for the purpose of state of the environment reporting has been neglected.
Data that has a spatial component, rather than being aggregated to the regional reporting level, should be used and maintained in a Geographical Information System.
Look forward, not backward.
State of the environment reporting tends to look at what has happened instead of investigating where things are headed. The latter is much more important than the former for policy and decision makers.
1 Ryan Metcalfe, Steve Diggon, Carl Burgess, Robin Green, Marnie Eggen, Brian McHattie, Mark Conrad, Clint Johnson are undergraduate ERS students who have worked on developing a framework for monitoring ecosystem integrity in the Huron Natural Area.
2 Kay & Schneider, Schneider & Kay 1994, Allen and Hoekstra 1992
3 Woodley, 1993 T.F.H. Allen, 1982, 1992, 1993, A. King 1993, F. Günther and C. Folke, 1993
4 R. Thom, 1969;K. Huseyin, 1977
5 Stigliani, 1988;
6 Alley,et al., 1993; Fairbank, 1993
7 Kay, 1991
8 C.S. Holling, 1986,1992
9 Taken from M. Scheffer et al. (Added since this was written: A more extensive discussion of these attractors can be found in Regier and Kay, 1996 and Kay and Regier, 1999.)
10 Nicolis and Prigogine, 1977, 1989
11 Schneider and Kay, 1994a &b.
12 R.E. Ulanowicz, in press
13 Kay, 1991
14 Edwards & Regier, 1990; Costanza, Norton & Haskell; 1992; Woodley, Kay and Francis, 1993; Slocombe.
15 Woodley, Kay, Francis, 1993
16 Slocombe, 1993c is a collection of generic SOER sustainability criteria
17 Funtowicz and Ravetz, 1993, 1994.
18 This represents a synthesis of conversations with several practitioners and the overview papers of Slocombe (1993a,b,c) and Woodley (in press).
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