[MAIPC] Species die. Get over it with a few revisions

[Marc Imlay]

In the Washington Post today in Outlook, Mr. only humans count, made many
mistakes of course. I would like to start with his summary of mass
extinctions  that "come every 50 million to 100 million years, and
scientists agree that we are now in the middle of the sixth extinction, this
one caused primarily by humans. the sixth extinction will be followed by a
recovery, and later a seventh extinction, and so on." We should read the
scientific literature on mass extinctions. The first mass extinction
eliminated two thirds of the fundamental basic forms of life forever. Over
all there is a threshold level of degree of damage from mass extinction so
that for some there is recovery, although it takes millions of years, and
above that threshold there is not recovery. Studies have shown that with our
current conservation efforts we can keep the sixth extinction below that
threshold, but only if we continue that effort. So set aside natural areas
making sure that keystone species are kept there. For example, the keystone
crayfish burrows in wetlands that freeze over, support about a dozen aquatic
species about a foot or two below ground level because the temperature is
about 50 degrees (symbiosis). When the endangered species Act of 1973 was
passed studies showed that new species evolved at less than 1 percent of the
rate they were becoming extinct, because of us. Responses to that Act has
helped a lot.  Host specific, effective, biological controls of non-native
species has helped a lot. Japanese Knotweed is no longer as bad a problem
that it was in Great Britain as a result. Cheers 

 Marc Imlay, PhD

MD Chapter, Sierra Club, Natural Places Working Group Chair 

 



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