Science Serving Maryland's Coasts

Yasiel Figueroa, University of Puerto Rico

Class Year: 

Project Title: 

The Effects of Plant Density on the Morphological and Biomechanical Properties of a Tidal Wetland Macrophyte: Zizania aquatica


Tidal freshwater wetlands provide a variety of ecological and social benefits such as habitat and protection of shorelines from storm surges. Unfortunately, sea level rise and development pressures have greatly impacted these ecosystems. Widespread historical wetland losses and ongoing vulnerability underscore the importance of understanding tidal wetland responses and resilience to stressors in order to achieve successful management of these resources. Recently reported accelerated rates of sea level rise are of particular concern. The role of wetland macrophytes in responding to sea level rise by changing stem density and morphology to create feedbacks with sediment capture has been well documented in tidal salt marshes. In some cases, the plasticity of these morphological responses results in changed structural characteristics of the plants. However, these processes have been less well studied in freshwater tidal systems. This study carried out field manipulations of Zizania aquatica, a dominant species in tidal freshwater marshes of the Chesapeake Bay. Morphological and biomechanical measurements were documented in control and experimentally thinned, lower density plots. The plants growing at a lower density were structurally stronger as demonstrated by computing a "factor of safety" that relates the biomechanical load capability of the stems to ambient forces. This study concludes that plant density influences the morphological and biomechanical characteristics of Zizania aquatica.