Cupressaceae

Callitris drummondii (Parl.) F.Muell.

A small tree or shrub endemic to the southern coastal areas of Western Australia. Habitat fragmentation, indirect effects of introduced diseases and increasing fire frequencies pose potential threats.

Distribution

Restricted to southern Western Australia, in an area along or near the coast from Albany east to Cape Arid. Its extent of occurrence is estimated to be about 28,000 km2 with an estimated area of occupancy of at least 400 km2

Habitat and Ecology

A shrub or a small tree usually found on the margins of swamps, salt lakes and streams and in coastal sandhills.

Human Uses

Several Callitris species, including C. drummondii have potential as natural sources of deoxypodophyllotoxin, a precursor of a drug used in cancer treatment (Renouard et al. 2015).

Conservation Status

Global Status

Near Threatened

Global Rationale

Callitris drummondii was originally assessed in 1998 as Vulnerable under criterion A1c (a population reduction of 20% over the last 3 generations and a decline in area of occupancy, extent of occurrence and/or quality of habitat). Population reduction was attributed to clearing for agriculture, the effect of repeated fires and overgrazing.

Under the new categories and criteria (Version 3.1), criterion A1 requires that the extent of past decline must have been between 50 and 70% to qualify for Vulnerable. In this case the extent of past decline was estimated to have been 20% which is insufficient for the new threshold. Under A2, the extent of past decline must be more than 30% but less than 50%: again, the previous estimate is below this threshold and, in the absence of significant known decline since 1998, the criteria for A2 are also not met. Criteria A3 and A4 require estimates of future decline: these are currently unavailable.
The extent of occurrence is estimated to be about 28,000 km2. Its area of occupancy is calculated to be at least 400 km2 - this is based on representative herbarium specimens and a standard IUCN 4 km2grid. It is known from more than 10 locations and subpopulations, although reduced and fragmented to some extent, are not considered to be severely fragmented. On this basis then, it is not eligible for listing under under criterion B. In the absence of estimates for population size estimates or any population viability analyses, criteria C, D and E are not applicable. Currently, C. drummondii does not meet any criteria for listing in any threatened category. Should a decline in extent of occurrence, area of occupancy or quality of habitat in the near future become apparent, then it could qualify under the criteria A2c or A3c. On this basis, C. drummondii is assessed as Near Threatened.

Global Threats

Habitat loss has been a problem in the past; in some areas overgrazing and increased fire frequencies are an ongoing problem. In some parts of its range, Phytophthora cinnamomi dieback is causing the death of associated species. Although C. drummondii is not known to be susceptible, dieback of surrounding vegetation could increase risk of fire due to increased fuel loads.

Conservation Actions

This species is known from several national parks and flora reserves particulalry around the Fitzgerald River

References and further reading

  1. McCraw, L. 2007. Callitris in the woodlands and shrublands of southern Western Australia: ancient landscapes, contemporary issues. 'Growing forest values', Australian and New Zealand Institute of Forestry (ANZIF) Conference, 3-7 June 2007, Coffs Harbour.
  2. Piggin J, Bruhl JJ. 2010. Phylogeny reconstruction of Callitris Vent. (Cupressaceae) and its allies leads to inclusion of Actinostrobus within Callitris. Australian Systematic Botany 23: 69–93.
  3. Renouard, S., Corbin, C., Colas, C., Fidel, T., Lopez, T., Leclerc, E.A., Hendrawati, O., Falguières, A., Doussot, J., Ferroud, C. and Maunit, B., 2015. Aerial parts of Callitris species as a rich source of deoxypodophyllotoxin. Industrial Crops and Products, 63, pp.53-57.
  4. Thomas, P. 2013. Callitris drummondii. The IUCN Red List of Threatened Species 2013: e.T34073A2843177. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T34073A2843177.en. Downloaded on 03 August 2017

External links