GEOG 5 Lecture Notes - Lecture 8: Insight, National Wildlife Refuge, Chytridiomycosis
Document Summary
At least 42 % of the 6000+ known amphibian species are declining. Approximately 1/3 of all amphibian species are threatened. About 165 amphibian species are thought to have become extinct since the. Habitat loss, chemical pollutants, infectious diseases, uv radiation, climate change are all suspects. Chytridiomycosis, a fungal disease, has been found in 43 countries and 36. U. s. states; it exacerbates harm from other causes. A group of distinct organisms that are capable of interbreeding with one another in the wild but that do not interbreed with organisms outside their group. The number of different species in a community. Species have difficulty reaching and colonizing isolated places (e. g. , islands) Usually greater at the edges of adjacent communities than at the center of a community. Edge effect change in species composition that occurs at ecotones. In some areas long-term stable climates have enabled a wide variety of species to evolve over time and form very biologically diverse communities.
