TheImprovement ofTropical and Subtropical Rangelands

110 IMPROVEMENT OF TROPIOAL AND SUBTROPIOAL RANGELANDS
health (vigor) and reproductive status of species in the community
and, therefore, insight as to which species are likely to increase
or decrease. Knowledge of this sort will guide the selection of the
appropriate range improvement practice.
For more detailed information concerning techniques for vegetation
analyses, the reader is referred to Conant et al. (1983), a publication
prepared specifically for efforts in nonindustrialized countries.
Other M eClBUrement. Gnd 06,erVGtion, To help in the selection of individual
plant species for revegetation projects and programs, there
may well be other kinds ofon-site surveys or observations of plant resources
that should be taken. Depending on the goals of the improvement
practice, these may include growth forms and plant community
structures (that is, verticallayerings)j seasonal growth, development,
and maturity patterns, including the differences among gruses and
forbs, shrubs, and treesj and ecological conditions and trends (Pratt
and Gwynne, 1977), as these parameters are influenced by successional
cycles and degree of site deterioration.
Animals
Individually and collectively, animals have a major impact on the
physical environments and the plant communities with which they
are associated, and, as a result, can affect range improvement activities
in diverse ways. Depending on the activity, these impacts can
be beneficial, detrimental, or both. Some animals greatly influence
the ecosystem processes that are basic requirements for plant growth
and development, such as nutrient and water cycling. Successional
patterns are affected by other animals, by regulating competition,
development, and productivity among individual plant species and
communities of plants.
A major influence on the success ofrange improvement activities
is the grazing activity of larger ruminant herbivores. However, both
the positive and the negative roles that animals play in an ecosystem
should be considered in a site evaluation.
Many semiarid and arid lands furnish habitats for wild animals
and domestic livestock. Therefore, knowledge of animal types that
occur on a site, their distribution and routes of migration, and their
ownership or legal status can dictate, to some degree, the options for
range improvement.