TheImprovement ofTropical and Subtropical Rangelands

48 IMPROVEMENT OF TROPIOAL AND SUBTROPIOAL RANGELANDS
exploiting a particular environmental niche. Ifone is selling for cash,
the feedback loop between subsistence levels and environmental conditions
is 18llll effective. If demand for one's product is rising, price
increases can more than cover the loa of productivity because of
overexploitation of the environment. For example, as a pasture deteriorates,
a subsistence herder may only have milk and meat to eat,
while a commercial beef producer may for a long time experience
stable or even rising income levels. Free labor markets also reduce
the risk of degradation for the individual. The destruction of the
land may cause hardship, but the Poaibility ofwage labor in the city
always exists.
In the past, some form of ·passive- management occurred when
quantities ofstock died 88 a result of drought. Today, in many parts
of Asia and North Africa, herders can maintain herd numbers, even
when pastures and water are totally exhausted, by trucking water and
feed to their animals until rains restore pastures. The purchase offeed
and the delivery of water, often subsidized by governments during
droughts, leads to levels of overgrazing that would be impossible
for traditionalsubsiatence pastoraliats. An unintended consequence
of improving veterinary services and reducing disease is to remove
this ·natural- regulator of herd size. Another consequence of the
growth of the market economy is that individuals enjoy increased
economic independence. In traditional groups, each individual family
is dependent on others for survival. In such a setting, social prell8ure
and the threat of OIItracism may be sufficient to prevent deviant
behavior. The development of a market economy increases economic
diff'erentiation and may reduce consensus on resource management
questions.
Modernization has also contributed to the degradation of the
environment in some areas. Improved medical and veterinary techniques
have reduced the constraints that disease placed on human
and herd numbers. The development of roads and the introduction
of motor transport have caused some nomads to become more
dependent on herding as caravans have become 18llll profitable and
have probably encouraged the switch from camels to cattle. Roads
and trucks have also made it profitable to cut fuelwood or produce
charcoal at great distances from cities, and trucks make it possible
to increase the use of remote or poorly watered pastures (Thalen,
1979). In many cues, mechanised plowing and sowing have made it
profitable to plow up rangelands where rainfall is so erratic that only
one year in three witnessed sucC8llllful harvests. The introduction of