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{{Short description|Sequence of plant succession}}
{{Multiple issues|{{expert-subject|Geography|ex2=Ecology|ex3=Evolutionary biology|reason=Long-term stub, too technical for most people to understand|date=August 2009}}
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{{Use dmy dates|date=June 2024}}{{Use British English|date=June 2024}}
A '''psammosere''' is
Psammosere is a form of [[Xerosere|xerosere (or xerarch)]] succession, meaning it begins in an environment with limited to no [[Fresh water|freshwater]] availability.<ref>{{Cite web |title=Ecological Succession – Part 1 – Ecosystem structures & functions |url=https://ebooks.inflibnet.ac.in/esp01/chapter/19-ecological-succession-part-1/ |access-date=2024-06-07 |website=ebooks.inflibnet.ac.in}}</ref>
In a psammosere, the [[organism]]s closest to the sea will be [[pioneer species]]: [[Halophyte|salt-tolerant species]] such as [[Littoral zone|littoral]] [[algae]] and [[Salicornia|glasswort]] with [[marram grass]] stabilising the dunes. Progressing inland many characteristic features change and help determine the natural succession of the dunes. For instance, the drainage slows down as the land becomes more compact and has better soils, and the [[pH]] drops as the proportion of seashell fragments reduces and the amount of [[humus]] increases. [[Sesuvium portulacastrum|Sea purslane]], [[sea lavender]], [[meadow grass]] and [[Calluna|heather]] eventually grade into a typical non-maritime terrestrial eco-system. The first trees (or pioneer trees) that appear are typically fast-growing trees such as [[birch]], [[willow]] or [[rowan]]. In turn these will be replaced by slow-growing, larger trees such as [[Ash tree|ash]] and [[oak]]. This is the [[climax community]], defined as the point where a plant succession does not develop any further because it has reached equilibrium with the [[ecosystem|environment]], in particular the [[climate]].▼
== History ==
Psammosere's literal meaning is “originating on sand". It was named by [[Frederic Clements|Frederic E. Clements]] who described the sequence in ''Plant Succession'' 1916.<ref>{{Cite journal |last=Egerton |first=Frank N. |date=2009-01-01 |title=Homage to Frederic E. Clements, Historian of Plant Succession Studies |url=https://esajournals.onlinelibrary.wiley.com/doi/10.1890/0012-9623-90.1.43 |journal=The Bulletin of the Ecological Society of America |language=en |volume=90 |issue=1 |pages=43–79 |doi=10.1890/0012-9623-90.1.43 |bibcode=2009BuESA..90...43E |issn=0012-9623}}</ref>
== Sand dune systems ==
[[File:Snaking up the dune ridge - geograph.org.uk - 1016227.jpg|thumb|The second stage in a psammosere succession. Humans have trampled some of the grass in this area, making it more vulnerable to erosion.]]
In a psammosere, the [[organism]]s closest to the sea will be [[pioneer species]]:<ref name=":0">{{Cite book |last=Clements |first=Frederic Edward |title=Plant Succession: An Analysis Of The Development Of Vegetation (1916) |publisher=[[Carnegie Institution of Washington]] |year=1916 |isbn=978-1169366053 |pages=214 |language=English}}</ref> [[Halophyte|halophytes (salt-tolerant species)]] such as [[Littoral zone|littoral]] [[algae]] and [[Salicornia|glasswort]] with [[marram grass]] stabilising the dunes.
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The later stages of a psammosere appear when the sand stops moving due to lower wind speeds. These lower wind speeds can be because of distance from the shoreline or the formation of higher dunes, acting as windbreaks, or a combination of both of these factors.<ref>{{Cite journal |last=Waterman |first=W. G. |date=1922-09-01 |title=Development of Plant Communities of a Sand Ridge Region in Michigan |url=https://www.journals.uchicago.edu/doi/10.1086/333053 |journal=Botanical Gazette |language=en |volume=74 |issue=1 |pages=1–31 |doi=10.1086/333053 |issn=0006-8071}}</ref>
The process by which different stages succeed each other is known as "plant colonisation".<ref name=":0" />
=== Effect on pH ===
In an idealised coastal psammosere model, at the seaward edge of the sand dune the pH of the soil is typically alkaline/neutral with a pH of 7.0/8.0 particularly where shell fragments provide a significant component of the sand. Tracking inland across the dunes a [[podsol]] develops with a pH of 5.0/ 4.0 followed by mature podsols at the climax with a pH of 3.5 - 4.5.
=== Human effects ===
Psammosere succession is also extremely vulnerable to human activities. At beaches, footpaths over dunes will trample grass, creating exposed sand. This exposed sand can be blown away very easily, leading to the roots becoming exposed, leading to neighbouring plants dying. This creates [[Blowout (geomorphology)|blowouts]], which can set back the Psammosere.<ref>{{Citation |last1=Calvão |first1=Teresa |title=Impact of human activities on coastal vegetation – A review |date=2013 |journal= |page=7 |url=https://research.unl.pt/ws/portalfiles/portal/11856932/Impact_of_human_activities_on_coastal_vegetation_A_review.pdf |last2=Fernanda Pessoa |first2=Maria |last3=Cebola Lidon |first3=Fernando}}</ref>
Efforts have also been made to improve the Psammosere in some regards. Pine trees are in some areas an invasive species, and can take over heathland.<ref>{{Cite web |date=2023-09-01 |title=Pull a Pine at RSPB Arne 2023 |url=https://corfecastle.co.uk/events/pull-a-pine-at-rspb-arne-2023/ |access-date=2024-06-11 |website=Corfe Castle |language=en-GB}}</ref> The [[National Trust]] in the UK encourages people to pull up small Pine trees<ref>{{Cite web |title=Volunteering day with our rangers |url=https://www.nationaltrust.org.uk/visit/dorset/studland-bay/join-our-rangers-for-some-hands-on-countryside-work |access-date=2024-06-11 |website=National Trust |language=en}}</ref> as they can leave needles on the ground and prevent further psammosere succession.
== See also ==
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*[[Psamment]]
*[[Xerosere]]
== References ==
{{References list}}
== External links ==
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