General Introduction - Integrated Assessment of Health and Sustainability of Agroecosystems - page 8

of the agroecosystem is therefore a subsystem of a bigger ecosystem that is in turn
part of a wider environment (Kay, 1994).
A holon that has integrity must possess both monitoring and control structural
or functional relations between its components. Monitoring is an assessment of the
performance of the system. The monitoring subunit integrates signals that indicate
changes in either the internal or the external conditions. The control subunit pro-
vides the mechanisms through which the holon can adapt to the new conditions
(Checkland et al., 1990). Monitoring and control therefore require that there be at
least one measure of performance and a definition of what constitutes good or bad
performance (Checkland et al., 1990).
Performance can be judged based on three general criteria: efficacy, efficiency,
and effectiveness. Efficacy is when the processes involved are adequate to produce
the required output in sufficient quantities and with the required quality. Efficiency
is when the minimum possible resources are utilized during the process. If the vari-
ous outputs resulting from the activities within the holon are consistent with the
purposes and state of the larger whole in which the holon is a part of, then the criteria
of effectiveness is satisfied.

1.4.2 t h e h e A l t h C o n C e p t

For centuries, scholars and practitioners in the health sciences have struggled with
questions of physical abilities and disabilities, self-perceptions, remedies, and their
assessment (Waltner-Toews, 1996). Similar questions are asked of agroecosystems
today. Furthermore, the general methodologies for screening, diagnosis, risk assess-
ment, and fitness determination have been tested and applied in the health sciences
for decades (Waltner-Toews, 1996).
The health metaphor proceeds from the view that health is an objectively defin-
able state that, once described, can be effectively pursued. Health in the agroecosys-
tem context depends on more than biophysical integrity; it is equally dependent on
healthy socioeconomic processes, healthy human communities, and, more impor-
tantly, adaptive public policy (Rapport, 1995). Whether an agroecosystem is healthy
is therefore a socioeconomic judgment as well as a biophysical assessment. This
implies a degree of consensus among the stakeholders regarding what is a satisfac-
tory definition of ecosystem health (Bergeron et al., 1994).
In ecosystems, as in organisms, what constitutes health depends not only on
objective scientific criteria but also on subjective evaluation and value judgment
(Rapport et al., 1985) and is partly reflective of sociocultural phenomena (Labonte,
1991). The definition of health therefore varies and will continue to vary for different
units of concern, over time, and among cultures (Kark, 1979; Costanza et al., 1992).
Likewise, lists of health attributes will vary with different conceptions of health.
However, there may be attributes common to all, such as the notions of a harmonious
balance and the notion of capacity to achieve a purpose (Last, 1987).
Productivity, stability, equitability, and self-reliance are some of the health attri-
butes that have been described (Conway and McCracken, 1990; Gallopin, 1994a,
1994b). Health attributes are seen as emergent properties of agroecosystems. The
relative degree to which an ecosystem shows any of these attributes contributes to