Environmental Engineering Reference
In-Depth Information
terms of meat production, which had a marketed value, but also included
non-marketed products such as milk and manure. In addition, services
provided by the livestock were also valued, such as the provision of labour
and transport. Finally, Scoones also included the costs of production of
livestock in the study area, and made a comparison between the relative
benei ts of dif erent types of livestock production. This study was carried
out through a simple cost-benei t analysis, that is, the total value of any
animal was calculated as equal to the value or price of it and its products
minus the costs of production. Data on the production parameters of
livestock (for example, births, deaths, milk production, and so on) were
obtained though household surveys. A comparison of livestock productiv-
ity on dif erent soil types was also made to assess the ef ect of a change in
this ecological parameter. He found that the productivity of communal
cattle was higher than that of beef cattle in the same region and that this
was at least partly due to the higher stocking rate of the communal cattle.
Campbell et al. (1997) estimated values for both plant and animal wild-
life resources in a Zimbabwean savanna. A large number of products that
were used by the local population were identii ed, for example, i rewood,
wood for construction, fruit, birds and thatch. As with Scoones et al.
(1992), the total value of the ecosystem was calculated by multiplying the
amount of each good produced by its value. For many of these resources,
an economic value was imputed by subtracting the costs of production (for
example, labour and transport costs) from their market value. Two dif er-
ent methods were used to estimate how much of a good was produced by
each area of land. For products that were regularly used by households,
such as i rewood and some wild foods, the amount that could be sustain-
ably produced by the forest was taken to be the amount of the product used
(an assessment of sustainability was also made). However, for other goods,
such as wild fruits, the amount used was judged to be a proportion of the
total annual biological production. Thus, in these cases, an ecological analy-
sis was made of the productivity of each plant species each year. Although
not explicitly stated, in this latter case a simple production function was
therefore set up, where the quantity consumed by households equalled
a proportion of the quantity produced by the vegetation. Although the
analysis made by Campbell et al. was extremely precise and detailed it did
not include a valuation of the livestock and crops produced in the region.
Campbell et al. (2000b) compared the economics of four dif erent cattle
production scenarios in communal grazing lands in Zimbabwe. In this
study, data on inputs to, and outputs from, livestock production, and data
on prices, were obtained through surveys of households. This allowed the
researchers to identify relationships between the inputs into production
of livestock (for example, feeding, herding labour, dipping) and various
