Editing Diego Garcia (section)

===Vegetation===
[[File:Diego Garcia Mixed Species Marsh.png|thumb|A mixed-species freshwater wetland on Diego Garcia]]

The first [[botanical]] observations of the island were made by Hume in 1883, when the coconut plantations had been in operation for a full century. Subsequent studies and collections during the plantation era were made in 1885, 1905, 1939, and 1967.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix E1, p. 1.</ref> Thus, very little of the nature of the precontact vegetation is known.

The 1967 survey, published by the [[Smithsonian]]<ref>[[#Stoddart|Stoddart & Taylor (1971)]]{{page needed|date=September 2011}}</ref> is used as the most authoritative baseline for more recent research. These studies indicate the vegetation of the island may be changing rapidly. For example, J. M. W. Topp collected data annually between 1993 and 2003 and found that on the average three new plant species arrived each year, mainly on Diego Garcia. His research added fully a third more species to Stoddart.<ref>[[#Topp|Topp (1988)]], p. 2.</ref> Topp and Martin Hamilton of [[Kew Gardens]] compiled the most recent checklist of vegetation in 2009.<ref>[[#Hamilton|Hamilton & Topp (2009)]]</ref>

[[File:Diego Garcia Cocos Forest.png|thumb|left|upright|A thick forest of coconuts on Diego Garcia]]
In 1967, Stoddart described the land area of Diego Garcia as having a [[littoral zone|littoral]] [[hedge]] of ''[[Scaevola taccada]]'', while inland, ''[[Coconut|Cocos nucifera]]'' (coconut) was the most dominant tree, covering most of the island. The substory was either managed and park-like, with understory less than 0.5 m in height, or consisted of what he called "Cocos Bon-Dieu"&nbsp;– an intermediate story of juvenile trees and a luxuriant ground layer of self-sown seedlings&nbsp;– causing those areas to be relatively impenetrable.<ref name="Stoddart_143_160">F. R. Fosberg & A. A. Bullock (1971): "List of Diego Garcia vascular plants". In: [[#Stoddart|Stoddart & Taylor (1971)]], pp. 143–160.</ref>

Also, areas of remnant tropical hardwood forest are at the sites of the plantation-era villages, as well as ''[[Casuarina equisetifolia]]'' (iron wood pines) woodlands.<ref name="Stoddart_127_142"/>

In 1997, the United States Navy contracted a vegetation survey that identified about 280 species of terrestrial [[vascular plant]]s on Diego Garcia.<ref>[[#Sheppard Seaward|Sheppard & Seaward (1999)]], p. 225.</ref> None of these was [[Endemism|endemic]], and another survey in 2005 identified just 36 species as "native", meaning arriving without the assistance of humans, and found elsewhere in the world.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix E2, paragraph E2-2.</ref> No [[terrestrial plant]] species are of any conservation-related concern at present.<ref>[[#Sheppard Spalding|Sheppard & Spalding (2003)]], p. 40.</ref>
[[File:Diego Garcia Hernandia Forest.png|thumb|A ''Hernandia''-dominated forest on Diego Garcia]]

Of the 36 native vascular plants on Diego Garcia, 12 are trees, five are [[shrub]]s, seven are [[dicotyledon]] herbs, three are grasses, four are [[vine]]s, and five are [[fern]]s.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix E1, p. 4-3.</ref>

The 12 tree species are: ''[[Barringtonia asiatica]]'' (fish-poison tree), ''[[Calophyllum inophyllum]]'' (Alexandrian laurel), ''[[Cocos nucifera]]'', ''[[Cordia subcordata]]'', ''[[Guettarda speciosa]]'', ''[[Intsia bijuga]]'', ''[[Hernandiaceae|Hernandia sonora]]'', ''[[Morinda citrifolia]]'', ''[[Neisosperma oppositifolium]]'',<ref>{{cite web|url=http://www.ars-grin.gov/~sbmljw/cgi-bin/taxon.pl?412139 |archive-url=https://web.archive.org/web/20150903221255/http://www.ars-grin.gov/~sbmljw/cgi-bin/taxon.pl?412139 |url-status=dead |archive-date=3 September 2015 |title=''Neisosperma oppositifolium'' (Lam.) Fosberg & Sachet |publisher=[[United States Department of Agriculture]] |work=[[Germplasm Resources Information Network]] |access-date=27 September 2011 }}</ref> ''[[Pisonia grandis]]'', ''[[Terminalia catappa]]'', and ''[[Heliotropium foertherianum]]''. Another three tree species are common, and may be native, but they may also have been introduced by humans: ''Casuarina equisetifolia'', ''[[Hibiscus tiliaceus]]'', and ''[[Pipturus|Pipturus argenteus]]''.

The five native shrubs are: ''[[Caesalpinia bonduc]]'', ''[[Pemphis|Pemphis acidula]]'', ''[[Premna|Premna serratifolia]]'', ''Scaevola taccada'' (often mispronounced "Scaveola"), and ''[[Suriana|Suriana maritima]]''.

[[File:Premna Shrubland.png|thumb|right|A ''Premna''-dominated scrub land on Diego Garcia]]
Also, 134 species of plants are classified as "weedy" or "naturalised alien species", being those unintentionally introduced by man, or intentionally introduced as ornamentals or crop plants which have now "gone native", including 32 new species recorded since 1995, indicating a very rapid rate of introduction.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix E1, p. 4-5.</ref> The remainder of the species list consists of cultivated food or ornamental species, grown in restricted environments such as a planter's pot.<ref>[[#NRMP|Natural Resources Management Plan (2005)]], Appendix E1, p. 4-6.</ref>

[[File:Diego Garcia Cattail Marsh.png|thumb|upright|A freshwater marsh composed entirely of cattails located on the eastern edge of the bomber ramp on Diego Garcia]]

[[File:Diego Garcia Littoral Scrub 1.png|thumb|A typical oceanside littoral hedge with ''Casuarina'' fringe]]

In 2004, 10 [[plant community|plant communities]] were recognised on the atoll rim:<ref name="ReferenceA"/>
* ''Calophyllum'' forest, dominated by ''Calophyllum inophyllum'', with trunks that can grow in excess of {{convert|2|m|ft}} in diameter. This forest often contains other species such as ''Hernandia sonora'', ''Cocos nucifera'', and ''Guettarda speciosa'' with a ''Premna obtusifolia'' edge. When found on the beaches, ''Calophyllum'' often extends over the lagoon water and supports nesting red-footed boobies, as does ''Barringtonia asiatica'' found mostly on the eastern arm of the atoll.
* ''Cocos'' forest, essentially monotypic (''Cocos bon Dieu''), with the understory consisting of coconut seedlings
* ''Cocos-Hernandia'' forest, dominated by two canopy species—''C. nucifera'' and ''H. sonora''
* ''Cocos-Guettarda'' forest, dominated by the canopy species ''C. nucifera'' and ''G. speciosa'': The understory consists of a mix of ''Neisosperma oppositifolium'', with ''Scaevola taccada'' and ''Tournefortia argentea'' on the beach edge.
* ''Hernandia'' forest, dominated at the canopy level by ''H. sonora'': The most representative areas of this forest type are on the eastern, undeveloped part of the atoll. ''Calophyllum inophyllum'' and ''C. nucifera'' are often present. Understory species in this forest are often ''Morinda citrifolia'', ''Cocos'' seedlings, and ''[[Asplenium nidus]]'' (bird's nest fern), and occasionally, ''N. oppositifolium'' and ''G. speciosa''.
* ''Premna'' shrubland, occurring generally between marshy areas and forested areas: The most conspicuous vegetation is primarily ''P. obtusifolia'', with ''Casuarina equisetifolia'' and ''Scaevola taccada'' on the margins. The dense groundcover consists of species such as ''[[Fimbristylis|Fimbristylis cymosa]]'', ''[[Ipomoea pes-caprae]]'' (beach morning glory) and ''[[Triumfetta|Triumfetta procumbens]]''. ''Premna'' shrubland appears mostly adjacent to the developed areas of the atoll, particularly in the well fields.
* Littoral scrub lines almost the entire seashore and lagoon shore of the island. It is dominated by ''S. taccada'', but it also contains scattered coconut trees, ''G. speciosa'' and ''Pisonia grandis''. On the seaward side, it also contains ''Tournefortia argentea'' and ''Suriana maritima''. On the lagoon side, it may also contain ''[[Lepturus|Lepturus repens]]'', ''[[Triumfetta|Triumfetta procumbens]]'' and ''[[Cyperus|Cyperus ligularis]]''. Large pockets of ''Barringtonia asiatica'' are also on the eastern edge of the lagoon.
* Maintained areas of grasses and sedges routinely mowed: Aerial photographs of the island clearly display large areas of grasslands and park-like [[savanna]] upon which the United States military has constructed large outdoor facilities such as antenna fields and the airport.<ref>{{cite web |author=President for Life |url=http://www.zianet.com/tedmorris/dg/aerial2.html |title=Aerial Photographs of Diego Garcia |publisher=Zianet.com |access-date=21 June 2012 |archive-date=11 June 2011 |archive-url=https://web.archive.org/web/20110611010333/http://www.zianet.com/tedmorris/dg/aerial2.html |url-status=live }}</ref>{{Better source needed|date=July 2023}}
* Mixed native forest, with no dominant canopy species
* Marshes are divided into three different types: cattail (''[[Typha domingensis]]''), wetland, and mixed species. Cattail marshes contained almost entirely cattails. These areas are often man-made reservoirs or drainages that have been almost entirely monotypic. Wetlands were based upon vegetation that occurred in the area with fresh water. Mixed-species marshes were highly variable and usually had no standing water.