Editing Vernal pool (section)

==Flora==
[[Image:Vernal Pools 3.jpg|thumb|upright|Vernal pool flowers, with different species occurring in zones related to soil moisture and temperature gradients formed as the pool dries out. Sacramento National Wildlife Refuge, Calif.]]
In vernal pools, flowering occurs simultaneously because of the seasonality of favorable conditions. Vernal pool ecosystems may include both [[cosmopolitan distribution|cosmopolitan]] species and endemic species adapted to unique environmental conditions. These conditions include moisture gradients, salinity gradients, and reduced levels of competition.<ref name=":0" /> Microtopographical gradients also contribute to species distribution in vernal pool communities, where plants that flower sooner in the season are more likely to be found at slightly higher elevations than later flowering species. Many vernal pool plants have buried seeds which accumulate in the soil. Different species are suited to different moisture levels, and as water evaporates from the edges of a pool, distinctive zonation of species can be seen. Most pools receive annual deposition of tree leaves, which are critical to maintaining local life due to leaf detritus.

Many upland [[perennial plant]]s are unable to withstand the period of flooding. Many wetland plants are unable to withstand the period of desiccation. Therefore, vernal pools are a distinctive habitat that provides a refuge from both terrestrial and fully aquatic plants. When dissolved carbon dioxide is depleted by daytime photosynthesis, vernal pool species like Howell's quillwort (''[[Isoetes howellii]]'') and pygmyweed (''[[Crassula aquatica]]'') collect carbon dioxide nocturnally using [[Crassulacean acid metabolism]]. Vernal pool basin habitats favor annual plants with some uniquely adapted perennials which suffer extensive mortality resembling annual reproduction. Annuals comprise approximately 80 percent of vernal pool flora. Listed below are some genera of the approximately one hundred vascular plant species associated with California vernal pool habitats. A typical pool will include only 15 to 25 species.<ref>{{Cite book|title=Ecology, Conservation, and Management of Vernal Pool Ecosystems|last1=Bauder|first1=Ellen T.|last2=Belk|first2=Denton|last3=Ferrer|first3=Wayne T. Jr. |publisher=[[California Native Plant Society]]|year=1998|isbn=0-9434-6037-9|editor-last=Witham|editor-first=Carol W.|pages=2–3, 5}}</ref>

'''Cosmopolitan aquatic flora'''
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* [[Isoëtes|quillworts]] (perennial)
* [[Marsilea|water clover]] (perennial)
* [[Pilularia|pillworts]] (perennial)
* [[Callitriche|water starworts]]
* [[Crassula|succulents]]
* [[Elatine|waterworts]]
* [[Myosurus|mousetail]]
* [[Ranunculus|buttercups]]
* [[Eleocharis|spikerushes]] (perennial)
* ''[[Triglochin scilloides]]''
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'''Vernal pool specialists'''
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* [[Blennosperma|stickyseeds]]
* [[Downingia|calicoflowers]]
* [[Eryngium|button parsleys]] (perennial)
* [[Gratiola amphiantha|snorkelwort]]
* [[Legenere|false Venus' looking glass]]
* [[Navarretia|pincushion plants]]
* [[Plagiobothrys|popcornflowers]]
* [[Psilocarphus|woollyheads]]
* [[Neostapfia|Colusa grass]]
* [[Orcuttia|Orcutt grass]]
* [[Tuctoria|Solano grass]]
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Upland plants commonly found at vernal pools in California include [[Yellow Pansy|yellow pansies]], several sweet-scented [[clover]]s, yellow and bright lavender [[Mimulus|monkeyflowers]], [[Common Star Lily|star lilies]], and [[yarrow]].

Vernal pools are often threatened by development in the same way that other [[wetlands]] are. As a result, most pools have been converted into residential zones, roads, and industrial parks. That is why most extant pools occur on protected or private land such as [[national park]]s, and [[ranch]]es.

A large number of [[rare species|rare]], [[endangered species]], and endemic species occur in vernal pool areas. For example, the [[San Diego mesa mint]], a highly endangered plant, is found exclusively in vernal pools in the [[San Diego, California|San Diego]] area.<ref>{{Cite web|url=https://www.sandiegouniontribune.com/news/environment/story/2019-03-31/vernal-pools-habitat-rainfall-fairy-shrimp-endangered-species|title=Vernal pools: Rains bring to life mini-ecosystem of button celery, Otay Mesa mint and fairy shrimp|last=Brennan|first=Deborah Sullivan|date=April 1, 2019|website=San Diego Union-Tribune|language=en-US|access-date=April 5, 2019}}</ref> Another example is the [[wildflower]] ''[[Lasthenia conjugens]]'', which is found in limited parts of the [[San Francisco Bay Area]]. A third example is the herb ''[[Limnanthes vinculans]]'' endemic to [[Sonoma County, California]].{{Cn|date=May 2021}}