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The general approach to sustainability appraisal
The framework structure
Using evaluation factors
Indicators, criteria and thresholds
Achieving flexibility of subject matter
As discussed in Chapter 1, land use 'sustainability' can be seen as an extension of land use 'suitability' into the future. Exact definition of a form of land use suited to present land conditions is the objective of the FAO Framework for Land Evaluation (FAO, 1976). It is also a wise starting point for the FESLM.
Faced with a challenge to determine whether a particular land use activity can be sustained, the first task must be to examine and analyse the exact objective of the activity and the means by which it is being, or is planned to be, achieved. Once identified, these characteristics of the use may be related to those of the environment at the planned location; leading to a decision on the extent to which the latter meet the requirements of the former and will aid or constrain performance.
In essence, this is the approach adopted in the FAO Framework to determine whether a use is 'suitable'.
Experience and common sense provide the first measure of the likely impact of environmental characteristics on land use performance. Actual experiment and observation of like situations elsewhere provide more precise, even quantitative, evidence of cause and effect. Then, as observational evidence accumulates, increasingly reliable mathematical models can be developed to relate environmental characteristics to land use performance. Using these models, values for effects can be interpolated, or extrapolated, for situations in which land characteristics differ from those of the observed site.
Various ways of projecting response from one situation to another have been demonstrated. These include the use of direct measurements, simulation models or empirical assessments of assumed relationships between benefits and diagnostic criteria (FAO, 1976, pp. 36-37). Finally, a measure of 'suitability' is achieved by summing all the perceived positive and negative effects of present day interactions between land use and environment.
Similar methods can be used to predict sustainability within the FESLM, but because the FESLM looks to the future, there are two very significant complications:
• all trends of change with time need to be identified in the environment of the investigated site;
• the state of evaluation factors after predicted change must also be predicted, for they cannot be measured.
If these difficult steps can be achieved, an integrated assessment of 'suitability' at various future times (based upon the predicted status of the evaluation factors) effectively provides an assessment of sustainability throughout the period investigated.
Procedures for selecting
environmental attributes for use as evaluation factors in sustainability analysis are
discussed later in the context of constructing an Action Framework (see Chapter 4).
Certain attributes may prove especially helpful in evaluating the sustainability of particular uses-because their status is highly relevant to performance and because their instability in relation to known environmental pressures is highly predictable. Such attributes have been described as 'Indicators' of sustainability.
Sometimes specific levels or conditions of an Indicator attribute are seen to have special significance in sustainability evaluation and are described as 'Thresholds'. A 'Threshold' level might be one at which a significant change in the influence of an indicator occurs, or one beyond which further change in the indicator attribute would be unacceptable. The interacting processes and factors which determine 'Threshold' levels are termed "Criteria'.
The FESLM Working Group has defined 'Indicators', "Criteria' and 'Thresholds' as follows:
• INDICATORS: Environmental statistics that measure or reflect environmental status or change in condition (eg. tonnes/ha of erosion; rate of increase/decrease in erosion)
• CRITERIA: Standards or rules (models, tests or measures) that govern judgements on environmental conditions (eg. impact assessment of the level of erosion on yield, water quality etc.)
• THRESHOLDS: Levels beyond which a system undergoes significant change; points at which stimuli provoke response (eg. a level beyond which erosion is no longer tolerable).
The recognition of 'thresholds' (by
applying 'criteria' to measurements of 'indicators') will provide powerful tools in
deciding whether or not a chosen land use will be sustainable.
Flexible procedures are a great advantage in any diagnostic system. If well chosen, flexibility can prevent a procedure coming to a premature stop by providing an alternative path forwards. Considerable flexibility is achieved in FAO's Land Evaluation Framework by allowing the evaluator to continuously adapt his land use definition to meet environmental constraints as these are recognized. This 'two steps forward one step backward process' known as 'iterative matching' - can be pursued until, hopefully, a complete management package capable of meeting all the local environmental constraints is designed - a 'suitable land utilization type'. This final package, indeed a variety of alternative packages, may bear little resemblance to the land use originally explored or the use currently occupying the site (FAO, 1976).
This approach is well suited to Land Evaluation for which the main aim is to identify alternatives of land use suited to the site in question. It is less appropriate for sustainability evaluation for which the initial aim, at least, is to determine the sustainability of a particular form of use-normally the present use of the site. A client, having asked whether a certain use is sustainable, may not be content with an evaluation of a different use-certainly not if the use objective is different!
At the same time, it has to be recognized that adaptation of a land use system in response to changed circumstances is normal practice in all fields of land use. In the FESLM a sharp distinction is drawn between the 'objective' of a land use and the 'means' by which it is achieved.
The FESLM does not claim to cope with unforeseen change but, if change is foreseen, the procedures allow for adaptation of the use in one of three ways:
• the definition of the use to be evaluated can stipulate the need for progressive or step-wise adaptation as foreseen changes occur (the evaluation would then take account of these changes as the analysis proceeds - the need for adaptation being agreed with the client in advance).
• if a future need for minor changes in the means employed (not in the use-objective) is detected as the evaluation proceeds these can be incorporated in the final report as a qualification of the definition of the No.1 Use evaluated (minor change in fertilizer usage, introduction of pesticides, change in marketing policies etc., would be examples in an agricultural context of the kind of minor change envisaged).
• if, when the evaluation is already underway, a need is detected for future significant change in the means employed this implies that the investigated use, as originally defined, is unsustainable. This will be reported. Meanwhile, the evaluation can be restarted to re-explore the original use-objective but with redefined 'means' - means modified in the light of the earlier evaluation findings. (These modified means become a part of the definition of 'Use No. 2' within the original evaluation).
Note, none of these alternatives allow for a change in the use-objective. One cannot begin to evaluate arable farming and end up proposing a golf course! A new use-objective becomes the subject matter of a new evaluation.
Thus, although the FESLM lacks the flexibility of subject matter enjoyed by the FAO Framework, some measure of flexibility remains.
Earlier in this text the Framework has been called 'a logical pathway' - a pathway that seeks to connect the form of land use under investigation with the multitude of environmental characteristics which, together, seem likely to determine whether that form of land use is sustainable. It does so through a series of pre-determined stages.
So large is the range of environmental characteristics potentially bearing upon sustainability that, without a systematic approach, it would be impossible to identify any but the most obvious factors influencing a specific use, much less the complex interactions known to affect sustainability. In time, as our understanding of these problems increases, the range of factors and interactions to be considered will be so extensive that only a computer could handle the number of comparisons that will need to be made. Indeed, the sooner the Framework is computerized the better. A logical pathway is essential, of course, to computerized analysis.
The FESLM pathway is shown, in simplified form, passing through the centre of Figure 1.
There are two main stages of the pathway. The first stage, with two levels, defines the purpose of the evaluation-WHAT is to be evaluated. The second stage, with three levels, defines the process of analysis-HOW the evaluation is done.
The titles and intentions of the 5 levels are as follows:
The Purpose: (What?)
identifies the land use system to be evaluated in terms of its purpose, its location, and the time period for sustainabilityLevel 1: Objective:
Level 2: Means: defines the management practices to be employed to attain the Objective
The Analysis: (How?)
identifies the qualities, attributes, processes, controlling interests or constraints which affect sustainability in the context of the evaluation and against which the sustainability analysis is conductedLevel 3: Evaluation Factors:
Level 4: Diagnostic Criteria: (causes, effects and observations): identifies how the selected evaluation factors impact on sustainability - through analysis of available information, modelling, expert systems and, if need be, experimentation
Level 5: Indicators and Thresholds: identifies measurable or observable attributes which, in time projection, reveal the future status or condition of the evaluation factors and which individually, or together, provide a measure of sustainability
Conclusions on the probable
sustainability of the land use system are drawn together in an 'Assessment end point'.
These conclusions require to be validated by re-examination of all the steps in the
analysis. In particular, this reexamination should ensure that there has been consistency
throughout in the application of the Framework Principles and procedures and in teens of
the five principles of sustainable land management.
The range of circumstances in which sustainability may need to be evaluated is immense. For this reason it is planned that the FESLM should embrace two kinds of framework:
a reference text. Not tied to any specific land use objective, any specific location, any scale of interpretation or any stated period of time; but describing and explaining the complete diagnostic pathway and (eventually) including a comprehensive checklist of factors, criteria, indicators and thresholds that may be relevant to sustainability evaluation in all foreseeable circumstances• A 'Master' (or 'Reference') Framework:
• 'Action' (or 'Local') Frameworks: each developed to investigate the sustain-ability of a specific kind of land use, at a specific location, at a specific scale, over a stated period of time; using the pathway, and factors, criteria, indicators and thresholds selected from the Master Framework as relevant to the specific conditions.
The complete structure of the Master Framework and the method of constructing an Action Framework are described in Chapter 3 and 4, respectively, which follow.