JULY 2015 • NEBRASKAland 45
category. These grasses form tall
and/or dense mats of vegetation
aboveground and thick masses of
roots belowground, both of which
monopolize resources and help prevent
other plants from gaining or keeping
a foothold. You wouldn't call them
sprightly, but occupiers hold their
position and slowly and surely expand
their dominance until something more
powerful weakens them.
Historically, there were four major
forces that could stop those dominating
occupiers: fire, grazing, drought and
flooding. Today, herbicides, mowing
and cultivation can be added to that list.
Above: These four-point evening primroses at the Nature Conservancy's Platte River Prairies are biennials that germinated in huge
numbers following the 2012 drought and bloomed in 2014. Below: The drought of 2012 weakened plant communities, especially on
sites like this one that were burned and grazed that year. During the recovery from that drought many showy wildflowers flourished
across the state. In this July 2012 photo, most perennial grasses have already given up on their year's growth and entered
dormancy. Most of the green is western ragweed, a plant that grows well in the absence of strong grass competition.
