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Desmarestia tropica 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Chromista Ochrophyta Phaeophyceae Desmarestiales Desmarestiaceae

Scientific Name: Desmarestia tropica W.R.Taylor
Common Name(s):
English Tropical Acidweed

Assessment Information [top]

Red List Category & Criteria: Critically Endangered (Possibly Extinct) A2a ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Annotations:
Needs updating
Assessor(s): Miller, K.A., Garske, L. & Edgar, G.
Reviewer(s): Stuart, S.N. & Carpenter, K.E. (Global Marine Species Assessment Coordinating Team)
Justification:
This is a conspicuous species that has not been observed since 1972, despite directed surveys in the type locality and other deep, cool locations around the archipelago. It inhabits cool water and has likely been affected by El Niño events in the last three decades, particularly the 1982-83 event, which greatly reduced macro-algal coverage across the archipelago. Since this species was found at two locations historically, and has not been found in recent decades, a 100% reduction in known populations is evident. A cryptic gametophyte stage may exist in deeper waters, but there is no evidence that it has been reproducing to produce the more conspicuous sporophyte stage. The species is Possibly Extinct.
Date last seen: 1972

Geographic Range [top]

Range Description:Desmarestia tropica is endemic to the Galápagos Islands, only known from two locations: Floreana: Post Office Bay (Taylor 1945: type locality). Second locality: Collected in 1972, Caleta Tagus, Isabela.

Acleto (1973) reported this species from Peru; however, this report is considered an error. [A. Peters annotated a specimen and indicated that the identification was incorrect, K.A. Miller pers. comm.]
Countries occurrence:
Possibly extinct:
Ecuador (Galápagos)
FAO Marine Fishing Areas:
Possibly extinct:
Pacific – southeast
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Unknown. No abundance estimates from type description. This is a conspicuous species that has not been observed since 1972, despite directed surveys in the type locality and other deep, cool locations around the archipelago. It inhabits cool water and has likely been affected by El Niño events in the last three decades, particularly the 1982-83 event, which greatly reduced macro-algal coverage across the archipelago. Since this species was found at two locations historically, and has not been found in recent decades, a 100% reduction in known populations is evident. A cryptic gametophyte stage may exist in deeper waters, but there is no evidence that it has been reproducing to produce the more conspicuous sporophyte stage.
Current Population Trend:Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:Collected by dredge from 14 to 60 m depth. Belongs to a cold water order of algae that is rare in the tropics (K.A. Miller pers. comm.). The cryptic gametophyte stage of this species may exist in cooler, deeper waters; however, no recent evidence indicates reproduction to produce the more conspicuous sporophyte stage, which may be seasonal (K.A. Miller pers. comm.).
Systems:Marine

Threats [top]

Major Threat(s): El Niño warming events; the elevated (i.e., up to 5°C above long-term average) and persistent (i.e., >12 months) temperatures that characterize El Niño events are likely to negatively affect this cold water species (Edgar and Garske 2004).

Conservation Actions [top]

Conservation Actions: Historic records currently within the Galápagos Marine Reserve (IUCN category VI); Galápagos Archipelago Particularly Sensitive Sea Area (PSSA); Galápagos Island World Heritage Site (UNESCO N (i)(ii)(iii)(iv)), and Galápagos Island Man and Biosphere Reserve (UNESCO).

Citation: Miller, K.A., Garske, L. & Edgar, G. 2007. Desmarestia tropica. The IUCN Red List of Threatened Species 2007: e.T63585A12684515. . Downloaded on 16 August 2018.
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