Funding for this research was provided by:
U.S. Geological Survey (07HQAG0008)
National Science Foundation (EAR-0529922)
U.S. Geological Survey (G15AP00077)
National Science Foundation (EAR-1226343, OCI-114849)
National Science Foundation (OCI-1450451, EAR-1135455)
Article History
Received: 31 July 2016
Revised: 21 December 2016
Accepted: 2 January 2017
First Online: 3 February 2017