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Nososticta pilbara 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Arthropoda Insecta Odonata Platycnemididae

Scientific Name: Nososticta pilbara
Species Authority: Watson, 1969
Common Name(s):
English Pilbara Threadtail
Taxonomic Source(s): Schorr, M. and Paulson, D. 2017. World Odonata List. Revision 10 February 2017. Tacoma, Washington, USA Available at: http://www.pugetsound.edu/academics/academic-resources/slater-museum/biodiversity-resources/dragonflies/world-odonata-list2/.
Taxonomic Notes: Nososticta pilbara was originally described as a subspecies of N. solida in Watson (1969) and later elevated to a full species in Watson (1974).

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii)+2ab(iii) ver 3.1
Year Published: 2017
Date Assessed: 2016-04-08
Assessor(s): Dow, R.A.
Reviewer(s): Endersby, I. & Theischinger, G.
Contributor(s): Hawking, J.
Justification:
Nososticta pilbara is only known from a single stream system in Western Australia, and is threatened by ground water extraction. The species is known from a single location, with an estimated extent of occurrence (EOO) less than 5,000 km², an area of occupancy (AOO) that is likely <500 km², and there is an inferred continuing decline in quality of habitat (the falling water level of the Millstream Spring and from climate change). Therefore it qualifies for Endangered under criterion B (EN B1ab(iii)+2ab(iii)).
Previously published Red List assessments:

Geographic Range [top]

Range Description:

Nososticta pilbara is endemic to Australia, where its “known distribution is one of the most restricted of any Australian odonate, encompassing only the oasis of permanent waters, fed by the Millstream aquifer, along the Fortescue River in the Pilbara region of Western Australia” (Watson and Theischinger 1984). The known sites comprise only one location for threat assessment purposes. The extent of occurrence (EOO), based on a minimum convex polygon around known occupied HydroBASIN areas, is 3,316 km². However, Bush et al. (2014: Table S2) gives an estimate of the current extent of suitable habitat of this species as 199 km².

Countries occurrence:
Native:
Australia (Western Australia)
Additional data:
Estimated area of occupancy (AOO) - km2:100-200
Number of Locations:1
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species is said to be abundant where it occurs (Watson and Theischinger 1984).
Current Population Trend:Unknown
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:This species occurs “on both streams and deep river pools. Larvae … were collected under stones in running water” (Watson and Theischinger 1984).
Systems:Terrestrial; Freshwater
Continuing decline in area, extent and/or quality of habitat:Yes

Threats [top]

Major Threat(s): This species is threatened by extraction of groundwater for the nearby mining town of Millstream, which has “which has considerably lowered the water level of the Millstream Spring” Hawking (2009). This threat can only be exacerbated by any increase in the frequency and duration of droughts due to climate change. In 2010, the Government of Western Australia Department of Water’s drinking water source protection plan for Millstream Water Reserve stated “The extraction rules for Millstream are designed to limit impacts on high-value groundwater-dependent ecosystems and involve managing rates of groundwater-level decline and minimum groundwater levels” (Government of Western Australia 2010). Independent confirmation of this, in relation to the condition of habitat suitable for Odonata in the area, is required

Climate change is predicted to be a serious issue for species endemic to the Pilbara region: "Potential loss of endemic species in the Pilbara ... is predicted" Bush et al. (2014a). More specifically modelling of sensitivity to climate change in Bush et al. (2014b) predicts that under both medium and high emissions scenarios this species will have no suitable habitat left by 2055; in the same paper it is stated that "because it primarily occurs in a few groundwater-fed streams, it may persist in these refuge habitats in the future, resilient to the broader changes in climate", but since the ground water level is apparently falling as well, this may be a false hope.

Conservation Actions [top]

Conservation Actions:

There is an urgent need for more data on this species, e.g. is its range really as restricted as is currently known? Detailed research into the effects of the lowering of the Millstream Spring on the species, and on dealing with the predicted loss of habitat from climate change is needed and a management plan should be developed and put into place.


Citation: Dow, R.A. 2017. Nososticta pilbara. The IUCN Red List of Threatened Species 2017: e.T163583A87528344. . Downloaded on 29 July 2017.
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