The various Ensatina salamanders of the Pacific coast all descended from a common ancestral population ... A well-studied example of a ring species is the salamander Ensatina escholtzii of ...

The evidence is pieced together from details drawn from all over the world, but it adds up to a disturbing picture ... know that many more species are "living dead" -- populations so critically ...

Fluctuations in population ... mutualistic species vary with the density of another mutualistic species (Holland et al. 2002, Thompson et al. 2006, Holland & DeAngelis 2010). For example, as ...

Butterfly populations have dropped by 22% in the United States, according to a new study published Thursday in the journal Science.

Many US Bird Species Seen as Reaching Population 'Tipping Point' By Will ... and egrets that show some increases," Parr added. Some examples of common birds now in decline include the chimney ...