Development of Health and Sustainability Indicators for a Tropical Highlands Agroecosystem - Integrated Assessment of Health and Sustainability of Agroecosystems - page 148

various strategies and management options, then indicators must be amenable to an
objective assessment. Selection of indicators must also be tempered by practicality
and the cost of measurement in terms of time and money.
The CCME (1996) proposed a framework through which a suite of health and
sustainability indicators can be developed. First, a systemic description of the eco-
system under review is developed using a variety of methods, including participatory
approaches. Essential components of a systemic description of an agroecosystem are
goals and objectives of the human communities living in them and a definition of
what constitutes health for that agroecosystem. Indicators are then selected based on
identified health attributes, community goals, objectives, and values, and are guided
by a list of desired qualities for an indicator.
Under this scheme, categories of measures that reflect the goals and values of
the system are generated. Within each category, measures for which data can be
practically obtained are identified as potential indicators. The choice of a measure
in an initial list of indicators depends on its desired qualities as an indicator. Such
qualities include validity , which is the degree to which an indicator reflects changes
in the system (Dumanski, 1994); cost-effectiveness, timeliness; sensitivity; and ease
of measurement (CCME, 1996; Smit et al., 1998). Casley and Lury (1982) listed five
considerations when selecting indicators. (1) Can it be unambiguously defined in
the conditions prevailing? (2) Can it be accurately measured in the conditions pre-
vailing and at an acceptable cost? (3) When measured, does it indicate the state of the
agroecosystem in a specific and precise manner? (4) Is it an unbiased measure of the
value of interest? (5) When viewed as one of a set of indicators to be measured, does
it contribute uniquely to explaining the variation in health and sustainability?
Initially, a large number of variables meeting these criteria may be included in
the list of indicators. However, many of the variables first selected are unlikely to
provide important additional information relative to other variables in the group.
Thus, statistical and mathematical methods to develop useful subsets of indicators
can be very helpful in developing suites of indicators that optimize parsimony and
information provided. Such methods include principle components analysis and mul-
tiple correspondence analysis (MCA). This chapter describes how a group of indica-
tors of agroecosystem health and sustainability was developed for use in a tropical
highlands agroecosystem and an evaluation of their practicality and application.
6.2 PRocess and metHods
The objective was to develop a suite of indicators suitable for use by research-
ers, policymakers, and communities to assess the health and sustainability of the
Kiambu agroecosystem. Two broad approaches were used. The first was a participa-
tory process involving communities in the agroecosystem. Indicators developed in
this process were referred to as community-driven indicators . The second approach
derived lists of potential indicators from the stated agroecosystem problems, needs,
objectives, and goals and from suggestions—by a multidisciplinary team of experts—
of variables that were felt important. These were referred to as researcher-proposed
indicators . Figure 6.1 is a conceptual framework of the process used in this study to
develop suites of agroecosystem health and sustainability indicators.