Wildlife

Endangered species, habitat loss, and what preservation actually involves

The authoritative global record of extinction risk is the IUCN Red List, which has assessed well over 150,000 species and classifies more than 40,000 of them as threatened with extinction. Species are placed in categories — Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, Extinct — against published criteria covering population size, rate of decline and range, so an assessment can be checked rather than merely asserted.

Habitat loss and fragmentation is consistently the single largest driver of that risk, ahead of direct exploitation, invasive species, pollution and climate change. Fragmentation matters as much as outright loss: a population cut into isolated pockets by roads and development loses genetic exchange and becomes vulnerable to local extinction even where the total acreage looks adequate. This is why wildlife corridors, conservation easements and river-crossing structures appear so often in serious conservation plans.

In the United States the legal backbone is the Endangered Species Act of 1973, which prohibits the taking of listed species and requires designation of critical habitat and the preparation of recovery plans. It is the mechanism behind the recovery of the bald eagle, the American alligator and the peregrine falcon — species whose decline was driven substantially by pesticides, and which recovered once the pesticide was banned and the habitat protected.

Species that do unpaid work for us

  • Bats. Insectivorous bats consume very large numbers of night-flying insects, including agricultural pests; North American populations have been devastated by white-nose syndrome, a fungal disease first identified in 2006.
  • Pollinators. Around three-quarters of the world's leading food crops benefit to some degree from animal pollination, most of it by bees, butterflies, moths and beetles.
  • Predators. Removing top predators reliably destabilises the systems below them — the classic case being wolves, elk browsing pressure and streamside vegetation.
  • Butterflies and moths. Short-lived and habitat-specific, they are among the earliest and most sensitive indicators that a landscape is changing.

Useful and Interesting Links

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More on The-Environment.net

  • Nature — the forests and watersheds that make up the habitat itself.
  • Oceans — marine mammals, reefs and the pressures on them.
  • Kids — animal and habitat resources written for children.