Healthy Mosquito Ditch, Cape Cod (IMAGE) Ecological Society of America Caption A mosquito ditch draining a small pond in a Cape Cod salt marsh, at a healthy site in 2010. This ditch was constructed in the 1930s and has not widened since its construction, but has been colonized on both sides by Spartina alterniflora. This tall cordgrass traps sediment and builds new habitat, keeping the ditch narrow. Credit Tyler Coverdale Usage Restrictions Include credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.