Selectivity of extinctions

Vanished species are unlikely to be a random subset of the biota.

• Karr (Barro Colorado)--ground-dwelling birds suffered higher rate of extinction than canopy dwellers [6].

• The proportion of species threatened differs dramatically among taxonomic groups in the United States (Table 5; [9]).

  
  

  Table 5: The taxonomic distribution of endangerment in the United States.

  Group	Proportion threatened$^1$
  Freshwater mussels	69%
  Crayfishes	51%
  Stoneflies	43%
  Freshwater fishes	37%
  Amphibians	36%
  Flowering plants	33%
  Gymnosperms	24%
  Pteridophytes	22%
  Tiger beetles	19%
  Butterflies	19%
  Reptiles	18%
  Odanates	18%
  Mammals	16%
  Birds	14%
  $^1$Presumed/possibly extinct, critically imperiled, imperiled, or vulnerable