Livestock,rangelands and grasslands‐a specific case for the management of genetic resources for food and agriculture

摘要

Biodiversity, the variety and variability of animals, plants and micro‐organisms at the genetic, species and ecosystem levels, is important to sustain key functions of ecosystems, their structure, processes, and services.Agro‐ ecosystems are ecosystems in which humans exercise a deliberate selection on the composition of living organisms ; hence they continue to co‐evolve with economies, cultures, knowledge systems and societies.They contribute to food security and rural development and provide ecosystem functions and services.Although plant and animal genetic resources interact in many ways, their most direct interaction is in grasslands and rangelands, ecosystems which cover more than 25% of emerged lands and can only be productively used by ruminants.Many rangelands are the result of the co‐evolution of livestock activities with other components of the ecosystem,including plants,forests and wildlife.Although they appear.natural., some rangelands are very old, and grazing by herbivores has changed the composition of landscape and vegetation even before human interference.Other rangelands are very recent formations, created by man.