Wednesday, November 21, 2012

What is a freshwater wetland and what kinds are there in northern California?

Let's start with understanding what a freshwater wetland is.
A freshwater wetland is an aquatic habitat that contains non-saline water.
There are 4 main typed of Freshwater Wetlands in North America: Ponds and Lakes, Marshes, Swamps, and Peatbogs

o   A pond or lake is a well-defined basin that is filled with stagnant water and ringed by vegetation. It is fed mainly by rainstorms and snowmelt, and loses most of its water through seepage and evaporation. In hot, dry months, parts of a pond or lake may dry out, exposing mud flats. In shallow ponds or lakes, bottom rooted plants such as water lilies can reach the surface, while milfoils, pondweeds, and other submergent plants thrive below the surface.

o   A marsh is usually found near a river, lake or tidal waters. Marshes are subject to periodic flooding, and the water level can change drastically in a short amount of time. The boundaries of a marsh are not well defined, and in draught, a marsh can completely dry up. Marshes are overgrown with coarse grasses, sedges and rushes.


o   A swamp is essentially a wooded marsh. Unlike Marshes, Swamps can support trees, tall shrubs, herbs and mosses. Swamps are covered with still or gently flowing water during wet seasons.

o   A peatbog is a poorly drained area that is covered by mats of moss, which slowly decompose in successive layers and eventually form a material called peat. There are 2 types of peatbogs; Bogs and Fens. The water of a Bog is much more acidic than that of a Fen, due to the larger quantities of sphagnum moss and the more advanced process of decomposition in a Bog. The vegetation of a Peatbog is mainly Sedges, Spruce and low-growing members of the Heath family.



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