On Behalf of Endangered Species
The Federal Endangered Species Act recently turned 25 years old. Congress authorized it in December 1973, in response to a growing recognition that the planet is losing large numbers of species that we are unable to gauge the value of and that we have no way of replacing.Actually any loss of a species is by definition a loss of value. Not only do plants and animals provide us with important medical or genetic benefits, such as cures for diseases and more productive agricultural crops, but species have value merely by existing.
It is a given in biology that the more species there are in an ecosystem the more stable, productive and resilient that ecosystem will be. In biological and evolutionary terms, prairies are superior to crop fields, bottomland forests are more productive than parks. Nature's richness is counted in species.
Thick lawns, waving fields of grain and huge flocks of snow geese suggest fertility and lushness to us, but such monocultures, in which a relatively small number of hardy, adaptable species dominate the landscape, are fragile, and their yields are relatively small. Research has shown that as the number of species declines, so does the total biomass, the amount of material produced as measured by dry weight. Low diversity also increases vulnerability. Fewer species means individual members of the same species grow closer to one another, and diseases can spread easily.
The Endangered Species Act is designed to counter severe losses in the world's biodiversity that have arisen largely as a result of human activities. It's unfortunate but true that the human species has been and continues to be the primary cause of the disappearance of many other species.
Humans have chopped down rain forests, overhunted mammoths and passenger pigeons, introduced rats, cats, mussels and other aggressive species to new places where they thrived at the expense of the species that had evolved there, cleared and cultivated vast areas for grain and other crops, paved over habitats, filled in wetlands, plowed under prairies, killed off insects and other "pests" and sent millions of tons of pollutants into waterways and oceans. We've discharged chlorofluorocarbons into the atmosphere, disrupting the ozone layer, and may have dramatically altered the weather of our planet with our carbon dioxide emissions.
Our impact on the planet is unprecedented, comparable in scope to previous mass extinctions caused by stellar or geologic events. Scientists speculate that we may eventually cause the disappearance of one-half