Conserving Populations and Species
  •   Protecting and managing a rare or endangered species requires a firm grasp of its ecology and its distinctive characteristics (sometimes called its natural history). Long-term monitoring of a species in the field can determine if it is stable, increasing, or declining in abundance over time.

  •   Population viability analysis (PVA) uses demographic, genetic, and environmental data to estimate how various management actions will affect the probability that a population will persist until some future date. It can be used to calculate the minimum viable population (MVP) size: the smallest population size that can be predicted to have a high chance of persisting for the foreseeable future. The MVP for many species is at least several thousand individuals.

  •   A species may be best described as a metapopulation made up of a shifting mosaic of populations that are linked by some degree of migration.

  •   The IUCN has developed quantitative criteria for populations and ecosystems to assign species to conservation categories: extinct, extinct in the wild, critically endangered, endangered, vulnerable, near threatened, least concern, data deficient, and not evaluated.

  •   Priorities for protection can be determined in several ways, including the species approach, the ecosystem approach, the wilderness approach, and the hotspot approach.

  •   National governments protect biodiversity by establishing national parks and refuges, controlling imports and exports at their borders, and creating regulations for air and water pollution. The most effective law in the United States for protecting species is the Endangered Species Act (ESA).

  •   International cooperation is needed to protect biodiversity because species migrate across border, there is an international trade in species, and biodiversity provides advantages to all countries.

  • At the international level, the Convention on International Trade in Endangered Species (CITES) allows governments to regulate, monitor, and sometimes prohibit trade in individuals and products from endangered species.

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