How do management treatments affect invasive cattail (Typha x glauca) and nutrient cycling in wetlands?

Abstract

In the last 50 years, industrial agriculture has largely contributed to the quadrupling of biologically available nitrogen and phosphorus through the excessive use of fertilizers. Excess nutrients run-off into wetlands, causing water and soil enrichment that promotes plant invasions. Typha X glauca, is a common invasive plant throughout eastern North America, where managers use harvesting, mowing, or herbiciding to control its dominance, but it is unknown how these treatments effect nutrient cycling. This study tested how these treatments affect wetland nutrient content (NO3-, NH4+, PO4-) in soil pore water, native and Typha density, and light attenuation curves. After 17 days, herbicide had higher PO4- concentrations (p=0.004) than harvest treatments, and 24 days after treatment, herbicide had higher phosphate concentration (p=0.05) than all other treatments. Harvest treatments promoted higher native density than mowing or herbiciding, which may be a result of increased light penetration to the soil surface. Together, these data suggest that harvesting has multiple benefits and should be considered by managers aiming to reduce Typha density, increase native abundance, and avoid leaching nutrients downstream.