Assessment Rationale:

Agdistis cambriana is endemic to the small and remote island of St Helena in the South Atlantic Ocean and one of three endemic species of the genus Agdistis (besides A. marionae, A. sanctae-helenae). This species was discovered in 2011 and has been found to be restricted to the dry valleys of Jamestown and Rupert's Valley in the north of the island. The habitat of this species is in decline due to the expansion of invasive plant species such as Schinus terebinthifolius (Wild Mango) and Furcraea foetida (English Aloe) which can become dense enough to exclude other vegetation, including Samphire. Additionally Rupert's Valley is an industrial area where there are plans to continue development, which will reduce available habitat. The species has a very low extent of occurrence (EOO) and area of occupancy (AOO) of 8 km². It is only known from 3 locations in the dry coastal area in the north of the island, where it is linked with the presence of Suaeda fruticosa (Samphire). Therefore Cambrian Agdistis is assessed as Endangered.

Geographic Range:

Cambrian agdistis is endemic to the island of St Helena, in the South Atlantic Ocean, where it is only found at the north dry coastal area (Jamestown, Rupert's Valley and Heart-shaped Waterfall) where Suaeda fruticosa (Samphire) is present. The species has a very small extent of occurrence (EOO) and area of occupancy (AOO) of 8 km²

Population:

A single female of this species was first collected in Upper Jamestown (Cambrian House) in 2011. In 2014 nineteen specimens were found in a malaise trap in Rupert's Valley near the junction. Another specimen was collected in 2016. During the DPLUS040 project in 2017/2018 ('Securing the future for St Helena's endemic invertebrates') 17 specimens were collected in malaise traps in Rupert's Valley and the Heart-shaped Waterfall. Current Population Trend: Unknown

Habitat and Ecology

Cambrian agdistis appears to be restricted to Jamestown and Rupert's Valley, an arid area to the north of the island. This species is mostly found in areas of sparse scrub vegetation on or around the native plant Suaeda fruticosa (Samphire), although it has not yet been confirmed if this is the host plant for larva or how A.cambriana and S. fruticosa are connected. These areas are close to non-native invasive plants that may encroach on this native Samphire habitat, including Schinus terebinthifolius (Wild Mango), Stenotaphrum secundatum (Mat Grass), Pennisetum macrourum (Thatching Grass) and Furcraea foetida (English Aloe). While S. fruticosa is found in many of the coastal valleys and other areas such as Prosperous Bay, no A. cambriana have been recorded at these sites. Systems: Terrestrial

Major Threat(s):

The key threats for Cambrian Agdistis are habitat loss and decline. Suaeda fruticosa (Samphire) is the native plant associated with this species, which faces competition from invasive non-native plants including Schinus terebinthifolius (Wild Mango) and Furcraea foetida (English Aloe) in its known sites. Additionally, Rupert's Valley is a developing area for industry and there are plans to continue this development in the future, therefore the habitat, particularly the area and extent of Samphire at these sites, will continue to decline due to ongoing disruption and the future construction works.

Conservation Actions

Further research on biology and habitat requirements for Agdistis cambriana is of key importance. The distribution, abundance and seasonality should be carefully recorded. Rupert's is an industrial area and Jamestown is a residential area, therefore there is little in place to protect the A.cambriana habitat from development. However, any invasive weed species clearance and eradication would be of benefit to reduce the negative impacts on this species. Agdistis cambriana and A. marionae are unable to be distinguished by the external features and so further surveys will help to determine whether this species is restricted to these locations.