Geoscience Reference
In-Depth Information
Fig. 7.1
The Rainwater Basin, located in south-central Nebraska, is an internationally significant
staging area for migratory waterfowl
white fronted geese, approximately 50% of mid-continent mallards, about 30% of
the continental breeding population of northern pintails and an increasing number
(>1.5 million) of lesser snow geese. In addition, during a typical fall, approximately
2.6 million waterfowl migrate through the RWB (Rainwater Basin Joint Venture
2008a
; USDA Natural Resources Conservation Service
2008
; LaGrange
2005
;
Gersib et al.
1992
). In addition to playing a critical role in supporting waterfowl,
RWB wetlands are important habitat for other wildlife, and also provide services
such as nutrient retention, floodwater storage and sediment trapping (LaGrange
2005
; Tiner
2003
).
Tiner (
2003
) characterizes the RWB wetlands as “geographically isolated,”
depressional wetlands created primarily by wind action on the nearly level silty
loess plains of south-central Nebraska. Prior to European settlement in the 19th
century, more than 200,000 acres of wetlands occurred in the RWB region, the
majority ranging in size from <1 to 40 acres with a few as large as 1,000 acres.
The wetlands derive most of their water from precipitation and surface runoff, how-
ever surface-water drainage in the RWB is poorly developed, so closed basins with
internal drainage predominate (Tiner
2003
).
Today, it is estimated that less than 20% of the original wetland area remains
(about 34-37,000 acres), and most of the extant wetlands exhibit some form of
degradation arising from siltation, fragmentation due to road construction and/or
invasions of exotic plants (Rainwater Basin Joint Venture
2008a
; USDA Natural
Resources Conservation Service
2008
; LaGrange
2005
; Farrar
1982
; Smith and
Higgins
1990
). The decreasing number and extent of wetlands have resulted in
greater bird density and increased the risk of disease. For example, it is estimated
that from 1975 to 1987 avian cholera killed more than 200,000 birds in the RWB
(Tiner
2003
; Smith and Higgins
1990
).
The Rainwater Basin Joint Venture (RWBJV) was created in 1992 to address
the problem of declining migratory waterfowl habitat. The principal goal of the
RWBJV is to restore and permanently protect remaining high-quality wetlands to
meet the habitat needs of waterfowl and other migratory birds (Rainwater Basin
