Editing Houtman Abrolhos (section)

===Flora===
{{Main|Flora of the Houtman Abrolhos}}
[[File:Nitraria billardierei.jpg|thumb|''[[Nitraria billardierei]]'' (nitre bush), pictured here in [[Adelaide]], South Australia, is the most widely distributed plant species in the Houtman Abrolhos]]

The [[vascular plant|vascular flora]] of the Houtman Abrolhos has been thoroughly surveyed, and species lists have been published for 119 islands. As of 2001, these lists totalled 239 species from 68 families. A further six species have been collected in the Houtman Abrolhos, but cannot be allocated to islands because insufficient location information was recorded. There have also been collections of [[moss]]es, [[Hepatica|liverwort]]s and [[lichen]]s, but no information has been published on these non-vascular groups.<ref name="Harvey 2001"/>

The islands with the greatest floristic diversity are East and West Wallabi Islands, with 124 and 97 species respectively. 54 species occur in all three island groups. The most widely distributed species are ''[[Nitraria billardierei]]'' (nitre bush), which has been recorded on 106 islands; the exotic ''[[Mesembryanthemum crystallinum]]'' (iceplant), on 88 islands; ''[[Threlkeldia diffusa]]'' (coast bonefruit), on 72 islands; and ''[[Atriplex cinerea]]'' (grey saltbush), on 70 islands. On the other hand, ''[[Eucalyptus oraria]]'' (ooragmandee) and ''[[Acacia didyma]]'' occur only on East Wallabi Island.<ref name="Harvey 2001"/>

As of 2001, five species of priority flora occurred on the islands.<ref name="Harvey 2001"/> One, ''[[Acacia didyma]]'', is no longer considered a priority species.<ref name="FloraBase 13079">{{FloraBase | name = ''Acacia didyma'' A.R.Chapman & Maslin | id = 13079}}</ref> The remaining priority species are  ''[[Chthonocephalus tomentellus]]'', which is rated Priority Two under the Department of Environment and Conservation's [[Declared Rare and Priority Flora List]];<ref name="FloraBase 7934">{{FloraBase | name = ''Chthonocephalus tomentellus'' (F.Muell.) Benth. | id = 7934}}</ref> ''[[Calocephalus aervoides]]'' and ''[[Galium migrans]]'', both Priority Three;<ref name="FloraBase 7887">{{FloraBase | name = ''Calocephalus aervoides'' (F.Muell.) Benth. | id = 7887}}</ref><ref name="FloraBase 322">{{FloraBase | name = ''Galium migrans'' Ehrend. & McGill. | id = 322}}</ref> and ''[[Lepidium puberulum]]'', Priority Four.<ref name="FloraBase 3043">{{FloraBase | name = ''Lepidium puberulum'' Bunge | id = 3043}}</ref>

Ninety-five exotic species from 29 families have been recorded. In general, islands that have or had human settlements are the weediest. Of greatest concern is the noxious weed ''[[Lycium ferocissimum]]'' (African boxthorn), which has long spines that can trap birds. This weed was recorded on the islands as early as 1970. Efforts to eradicate it began in 1990;<ref name="Harvey 2001"/> there was a lull in eradication in the late 1990s, but the program was later reinstated,<ref name="Fisheries 2007"/> and in July 2007, the Department of Environment and Conservation reported that the species had been eradicated from 14 of the 18 islands on which it had been recorded.<ref>{{cite web | title = African boxthorn eradication close | work = NatureBase | publisher = Department of Environment and Conservation, Government of Western Australia | url = http://www.naturebase.net/content/view/2828/770/  | access-date = 2008-01-01}}</ref> Other noxious weeds include ''[[Opuntia stricta]]'' (prickly pear),<ref name="Harvey 2001"/> ''[[Verbesina encelioides]]'' and ''[[Echium plantagineum]]'' (Paterson's curse).<ref name="Fisheries 2007"/>