The natural distribution and ecology of Blandfordia cunninghamii (Blandfordiaceae)

摘要

A survey covering almost all known sites and most areas of potential habitat of the rare plant Blandfordia cunninghamii (family Blandfordiaceae) in 2004 recorded over 4000 plants from 27 locations, with 80% of the plants in the upper Blue Mountains west of Sydney (lat 33° 40' S, long 150° 20' E), and the remainder as a disjunct occurrence on Mount Kembla in the Illawarra. Habitat requirements of Blandfordia cunninghamii were found to be southern aspect (SE to SW), a slope of > 30°, high rainfall (>1200 mm a year), good drainage, partial canopy cover (30-50%), and acid clayey sands with a pH of 4.5-5, at an altitude between 500 and 950 m. Using International Union for Conservation of Nature (IUCN) parameters, we consider that the number of plants(less than 10 000), their Extent of Occurrence (940 square km), Area of Occupancy (80 km~2) are below the threshold for Vulnerable. There is observed decline in habitat and numbers and we conclude that there may be less than 10 locations (under IUCN definitions). This would mean that the species could be considered Vulnerable under IUCN Criteria.