Orchid Habitat Loss
Calochilus pulchellus Summer (Australia) 2008 Update photos and text by Alan Stephenson
Calochilus pulchellus
Following the translocation in 2007 of several plants of Calochilus pulchellus from the path of a residential development I conducted several follow-up visits to hand water all plants to hopefully sustain them during what is the trauma of adjustment to a new site. This is despite the large section of earth left around the plants at the time of removal. Of all relocated plants I was of the opinion the plant in the stump would have a greater chance of survival than the others. How wrong I was, as in the flowering season of 2008 not only did this plant not flower but it seems a colony of ants has either eaten the tuber or undermined whatever was supporting it (rotted wood) and has disappeared.
Of the plants relocated two lots were not Calochilus pulchellus but turned out to be a very common species, Thelymitra ixioides. When assessing the plants from around the base of the stump I noted most had been nipped off by animals to a leaf length of 2 cm – 3cm (one inch), therefore the colour normally evident at the base of the leaf was not properly visible and the plants were relocated more on suspicion of being C. pulchellus than a definite identification. One plant later flowered but this was one of the original four plants noted during the original find on the site. This plant has survived and produced a single flower in 2008 and is now the only relocated plant expected to continue. Herein lies the perils of translocation, particularly a translocation carried out without time to undertake extensive surveys to determine a good habitat for the translocation. However late in the season of 2007 four extra plants were discovered and fortunately these are within the 53 hectare (20 acres) of habitat for Prasophyllum affine and Cryptostylis hunteriana (and pollinators) which is now surrounded by wire fencing. The four plants are within 20 metres of a control plot (one of seven) used to monitor the annual flowering vagaries of P. affine.
The good news for 2008 is that these four plants from 2007 have all flowered and within 2 metres I have found a further three flowering plants. Needless to say that during the 2009 monitoring of P. affine I will take time out to look for more plants of C. pulchellus as with the misidentification of some of the 2007 plants the C. pulchellus population still stands at approximately 30 plants. I did venture to the larger site containing 18 plants in 2007 and located 14 of these but in 2008 none were located on this site or at two other areas of suitable habitat within 10 km.
Alan W Stephenson
National Conservation Officer
Australasian Native Orchid Society (ANOS)
Conservation Director
Australian Orchid Council (AOC)