Editing Marsh (section)

===Freshwater marshes===
{{Main|Freshwater marsh|Wet meadow|Vernal pool|Dry lake}}
[[File:MeadowInBigBear.JPG|thumb|upright=0.9|A [[wet meadow]] adjacent to [[Big Bear Lake]], [[San Bernardino Mountains]], California]]

Ranging greatly in size and geographic location, freshwater marshes make up North America's most common form of wetland.  They are also the most diverse of the three types of marsh. Some examples of freshwater marsh types in North America are:

====Wet meadows====
[[Wet meadow|Wet meadows]] occur in shallow lake basins, low-lying depressions, and the land between shallow marshes and upland areas. They also happen on the edges of large lakes and rivers. Wet meadows often have very high plant diversity and high densities of buried seeds.<ref name="ReferenceA" /><ref>Keddy, P.A. and A. A. Reznicek.  1986.  Great Lakes vegetation dynamics:  the role of fluctuating water levels and buried seeds.  Journal of Great Lakes Research 12: 25–36.</ref> They are regularly flooded but are often dry in the summer.

====Vernal pools====
[[Vernal pool|Vernal pools]] are a type of marsh found only seasonally in shallow depressions in the land. They can be covered in shallow water, but in the summer and fall, they can be completely dry. In western North America, vernal pools tend to form in open grasslands,<ref>Bauder, E. T. 1989. Drought stress and competition effects on the local distribution of ''Pogogyne abramsii''. Ecology 70: 1083–9.</ref> whereas in the east, they often occur in forested landscapes.<ref>Calhoun, A.J.K. and P.G. deMaynadier. 2008. Science and the Conservation of Vernal Pools in Northeastern North America. CRC Press, Boca Raton, Florida.</ref> Further south, vernal pools form in pine savannas and [[flatwoods]]. Many amphibian species depend upon vernal pools for spring breeding; these ponds provide a habitat free from fish, which eat the eggs and young of amphibians.<ref name="ReferenceA" /> An example is the endangered [[gopher frog]].<ref>Richter, S. C. and Seigel, R. A. 2002. Annual variation in the population ecology of the endangered gopher frog, Rana sevosa Goin and Netting. Copeia, 2002, 962–72.</ref> Similar temporary ponds occur in other world ecosystems, where they may have local names.  However, vernal pool can be applied to all such temporary pool ecosystems.<ref name="ReferenceA" />

====Playa lakes====
[[Playa lake]]s are a form of shallow freshwater marsh in the southern high plains of the United States.<ref>Smith, L. M. 2003. Playas of the Great Plains. Austin, TX: University of Texas Press.</ref> Like vernal pools, they are only present at certain times of the year and generally have a circular shape.<ref>{{cite web|last=United States Environmental Protection Agency|title=Playa Lakes|url=http://water.epa.gov/type/wetlands/playa.cfm|access-date=5 February 2012|url-status=live|archive-url=https://web.archive.org/web/20120204144636/http://water.epa.gov/type/wetlands/playa.cfm|archive-date=4 February 2012}}</ref> As the playa dries during the summer, conspicuous plant zonation develops along the shoreline.<ref>Bolen, E. G., Smith, L. M., and Schramm, H. L., Jr. 1989. Playa lakes: prairie wetlands of the southern High Plains. BioScience 39: 615–23.</ref>