relative abundance


Hired out by their owners to the Commissioners of the District of Columbia, slaves helped construct both the U.S. Capitol and the White House.

Constructing the new city required a great deal of labor. White laborers were in somewhat short supply, but enslaved Africans were relatively abundant. They served as bricklayers, quarry workers, sawyers, and more. The capital could not have been built without them.

The Capitol’s dome was adorned with the Statue of Freedom on December 2, 1863. Philip Reid, while enslaved, had devised the means by which the statue’s plaster mold could be cast in bronze. Reid gained his freedom through the District of Columbia Compensated Emancipation Act of April 1862.

Image: Voucher for a slave who worked on the White House, paid to James Claggett, the slave’s owner, 1794. National Archives, Records of the Accounting Officers of the Department of the Treasury

Learn more about the history of enslaved people in the United States:

Some of the rarer elements are generated in the supernova explosion itself. We have relatively abundant gold and uranium on Earth only because many supernova explosions had occurred just before the solar system formed. Other planetary systems may have somewhat different amounts of our rare elements. Are there planets where the inhabitants proudly display pendants of niobium and bracelets of protactinium, while gold is a laboratory curiosity? Would our lives be improved if gold and uranium were as obscure and unimportant on Earth as praseodymium?
—  Carl Sagan

Bat Research Brings the #mypubliclandsroadtrip to #WomeninSTEM Wednesday

Today’s roadtrip continues in the Big Saline Bayou, Louisiana, for a behind-the-scenes with Alison McCartney. a BLM Southeastern States District Office employee whose specialty is bats.

“The BLM’s Southeastern States District Office is currently conducting acoustic surveys on BLM tracts in Alabama and Louisiana to determine bat species relative abundance and diversity.  We are using an Anabat SD2, which is a piece of equipment that records bat echolocation calls. Using specialized software, these calls can be analyzed to identify species. Our primary focus for the survey effort is to determine if there are any rare, threatened, or endangered bat species utilizing the tracts to better focus habitat management efforts to benefit these species, if present. 

We are also interested, however, in common species that might occur on the tracts. Bat relative abundance and diversity are considered an overall indicator of forest health. A higher abundance and species diversity of bats in an area represents a healthier more diverse forest.”

-By Alison McCartney