An Assessment of Health and Sustainability of a Smallholder-Dominated Tropical Highlands Ecosystem - Integrated Assessment of Health and Sustainability of Agroecosystems - page 181

7 An Assessment of

Health and Sustainability
of a Smallholder-
Dominated Tropical
Highlands Ecosystem

7.1 IntRoductIon
In an agroecosystem health and sustainability assessment, indicators should be ana-
lyzed in two ways: (1) as measures of overall health at a point in time and (2) as pre-
dictors of its long-term sustainability (Costanza et al., 1998) and health. Assessing
the health status of an agroecosystem involves comparing and contrasting a series
of indicator measurements against a set of cutoff and threshold values (Canadian
Council of Ministers of the Environment, 1996) based on the goals and objectives of
the agroecosystem.
A suite of indicators would in most cases contain several dozen variables. A
method of summarizing and presenting such data must preserve its holistic and mul-
tidimensional nature while providing meaningful, quantitative, and easily understood
criteria for evaluating agroecosystem health. One approach is to combine indicators
into indices such as total factor productivity (Ehui and Spencer, 1993), ecosystem
health index (Costanza, 1992), and agricultural sustainability index (Nambiar et al.,
2001). A fatal disadvantage of this approach is that indices place weights on dif-
ferent indicators without providing a rational basis for their (the weights') choice.
Another disadvantage is that these indices would eventually require some form of
decomposition to provide managerially useful information—a decomposition that
more often involves a reassessment of the initial suite of indicators used to compute
the index—and back to the initial problem of how to summarize information from
indicators. Less unencumbered by the latter, but still crippled by the weighting prob-
lem, are approaches such as ecological footprint (Wackernagel and Rees, 1997) and
the method proposed by Afgan et al. (2000) based on decision support systems and
the general indices method.
A systems approach to evaluating indicator data requires an understanding
of how agroecosystem goals and values are seen to relate to each other and to the
various social, biophysical, and economic phenomena that underlie the indicators.
Understanding the phenomena that data from indicators portray, however, requires a
systemic approach for two reasons. First, indicators are representations of complex

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