Past, Present, and Future

Historical Look: The slough's health has always been tied to sea levels. During the last ice age, sea level was about 120 m below current levels, and there was little wildlife presence. About 18,000 years ago, glaciers began to melt and sea levels rose to roughly where they are today. At first Elkhorn Slough had high-energy tidal activity as water rushed into the inlet, but about 8,000 years ago the tidal force decreased and sediment began to accumulate. As more sediment filled the area mudflats (areas of mud deposited by tides or rivers) and salt marshes (coastal grassland regularly filled with ocean water) formed.

Present Day -- Human Impacts:
Global Warming -- The Elkhorn Slough has been in danger for several years because of the effects of global warming. It is especially susceptible to rises in tide; because it sits at sea level, even moderate rises in tide can overwhelm the ecosystem and be disastrous for local species. 
Land Development -- Development of the land around the slough has led to tidal restriction which causes tidal erosion and marsh loss. The Moss Landing Harbor, built in 1947, had a terrible impact on the slough. The vegetation that was cleared to build the harbor left marshland farther inland more susceptible to erosion; this has resulted in significant marsh die-back in the last 60 years. Finally, as part of the development of the land, a local power plant was constructed near the slough. The plant is not only aesthetically unappealing, but it also limits the available land for plants animals of the slough, and it adversely affecting the water quality.

Agriculture -- Cattle farms pollute the soil with waste and grazing causes soil erosion stripping the land of nutrients. The Invasive non-native plants and animals mentioned above are disrupting the native species and competing for a limited amount of resources. Non-point source pollution from surrounding agriculture such as nutrient and pesticide rich runoff is impacting water quality and natural life both in the slough and in surrounding areas.

The Slough's Future -- Conservation Efforts: The Elkhorn Slough Tidal Wetlands Project is a program to implement strategies for conservation and restoration of the estuarine habitats in the watershed. The Parsons Slough Project aims to reduce to reduce the tidal prism in Elkhorn to minimize tidal marsh loss and habitat degradation. 
The National Estuarine research reserves host workshops, classes and field trips to educate the public about the importance of the ecosystem and our impacts

Currently over 8,000 acres of the slough, approx 18%, is under conservation protection by federal and state government. As hundreds of acres of agriculture are returned to maritime chaparral, and more land becomes protected under the federal government this ecosystem should be able to return very to it’s natural conditions.