Editing Marsh (section)

====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" />