Plant Community Structure and Forage Nutritive Value of Reed Canarygrass‐Invaded Wetlands

Abstract

Core Ideas Frequently harvesting reed canarygrass best maintains species richness in wetlands.Frequently harvesting reed canarygrass reduces its cover, a benefit to waterfowl.Reed canarygrass has nutritive value that exceeds needs of spring‐calving beef cows. Many wetlands across the United States have been threatened by reed canarygrass (Phalaris arundinacea L.) invasion. The use of reed canarygrass as forage may provide a revenue stream for agricultural producers while improving wetland ecosystem services. This study was conducted to evaluate the effects of forage harvest frequency (zero, one, two, and three times per year) on plant community structure and nutritive value in reed canarygrass–invaded wetlands. The research was conducted in two wetlands (North Lake Basin [NLB] and Straight Water [SW]), with frequently ponded soils in Seward County, NE, from 2011 to 2013. Harvesting three times per year best maintained plant species richness at NLB but had no effect at SW. Reed canarygrass cover was 14 and 12% greater in unharvested compared with harvested stands at NLB and SW, respectively, but forb cover was unaffected by harvest frequency at either location. Forage harvested increased with harvest frequency during the cooler and wetter years of 2011 and 2013 but was limited by drought during 2012. Crude protein (CP) and total digestible nutrients (TDN) in reed canarygrass and forbs did not show consistent responses to harvest frequency. Across locations and years, reed canarygrass had 88 to 159 g CP kg−1 and 534 to 680 g TDN kg−1. Harvesting wetlands more frequently decreases reed canarygrass cover and increases forage harvested, which are outcomes that could improve waterfowl habitat by increasing access to ponded water. The nutritive value of reed canarygrass at most times throughout the growing season exceeds nutritional requirements of mature, spring‐calving beef cows.