Animals in Agroecosystems - Agroecology: The Ecology of Sustainable Food Systems - page 273

HOLISTIC RESOURCE MANAGEMENT
In rangelands around the world, range managers and their herds of livestock are a relatively new presence. Not very
long ago, most of these lands were natural grassland, savannah, or shrubland grazed by herds of wild herbivores
preyed upon by large carnivores. In too many cases, conversion of these ecosystems to human-managed rangeland
has resulted in ecological degradation of various kinds — extensive soil erosion, loss of wetland habitat, replacement
of native plant species with exotics, simplification of community structure, and outright desertification.
Many ranchers, institutions, and researchers have been grappling with the problems of range management. One
of the more promising and agroecologically oriented approaches is that of Holistic Resource Management (HRM),
developed over the last several decades by Allan Savory and colleagues associated with the Savory Center as a
framework for creating sustainable grazing systems.
A foundation of HRM is the idea that we must mirror how animals work in natural grazing systems. When
treated as an integral part of the rangeland ecosystem, livestock animals can actually improve the functioning of
the system, increasing its productivity and stability.
In the typical rangeland environment, where precipitation and humidity are erratic, periodic disturbance is needed
to maintain soil cover, promote floral diversity, and promote fresh growth — plants neither grazed nor trampled are
suppressed or die under old leaves and stems that take many years to decay. In the past, this disturbance was provided
by large herds of grazing animals — bison, elk, deer, zebra, wildebeest, buffalo, kangaroos, and so on — that
constantly moved over the landscape, bunched tightly together to ward off predators that hunted in packs. The key
to sustainable grazing, therefore, is to use livestock animals to simulate the herbivory and trampling of native grazers.
For the range manager or rancher, this amounts to “getting animals to the right place at the right time and for
the right reasons.” At all times, the herd is affecting the soil, plants, and wildlife. If left in any one place too long,
or if returned to a place too soon, the animals will overgraze plants and pulverize soils. Therefore, livestock movement
is a key aspect of HRM, just as in natural grazing systems.
Under HRM, the land can produce the maximum amount of high quality forage in the growing season, on an
increasing or sustained basis, insuring that in the nongrowing months there is adequate forage and cover for livestock
and wildlife. In essence, HRM uses the herd to benefit the whole system — which includes the rangeland ecosystem,
its wildlife, its riparian corridors, and the economic enterprise of the rancher.
FIGURE 19.4 Cows improving woodland understory in southern Spain. Animals are moved through the system at key times
to manage herbaceous cover, promote tree development, and produce animal products.