Due to the highly variable conditions as a result of this mixing process, species diversity is low in this habitat. However, estuaries can be highly productive due to the nutrient supply from rivers and circulation that keeps the water well ventilated and resuspends nutrients and organic matter. Salt marshes are found on the upper edges of the intertidal zone in estuaries along temperate shores. The salt marsh plants are vascular plants and possess all the characters of terrestrial plants. This habitat is very productive and provides a complex habitat.
Mangroves are the dominant intertidal plants of the tropics and subtropics.
Mangrove swamps contain very diverse communities due to the complex habitat formed by the network of mangrove roots. The mangrove leaves provide a food source to the detrital food chain. Seagrass beds and meadows consist of vascular plants with long, thin blades. They are most abundant in low intertidal to shallow subtidal areas. They provide a nursuray area for juvenile fish and a complex habitat for many animals.