Publications

Action 4: Develop and initiate fine-scale site management practices

Endangered Caladenia taxa with critically low total population numbers will require urgent fine-scale management to ensure the survival of wild populations. Many suitable techniques have been successfully trialed for some endangered taxa (eg. C. amoena, C. audasii, C. hastata and C. rosella) and will be adapted and developed to suit other endangered taxa through an experimental approach.

4.1 Hand pollinate plants

Flowering and seed set are influenced by a number of factors and cannot be reliably predicted from year to year. Irregular flowering in orchid populations has been widely observed and information collected to date implies that poor flowering years tend to occur alternately, or following periods of dry weather (Hutchings 1987, Kindlemann and Balounova 1999, Light and MacConaill 1994). However, observations also suggest that climatic factors may not affect all taxa equally and that some taxa may be advantaged by abnormal weather patterns. In addition, it has also been observed that rates of natural pollination may be low in some Caladenia species (Peakall and Beattie 1996, J.Todd unpubl. data). Consequently, natural seed set and recruitment may be non-existent in some years and this represents a very serious threat to taxa with critically low population numbers.

To maximise seed production and hence the potential for recruitment during critical years, hand pollination of plants will occasionally be necessary, particularly within small populations. This will be determined for the various endangered taxa in spring during censusing. Pollen will be manually transferred between flowers on separate plants and records kept of cross-pollination.

Funds are required in the first two years of recovery to cover the salary and associated field costs of a project officer to carry out the work and to provide training to state department staff and volunteers who will be responsible for on-going hand pollination of plants. Travel costs will be covered by Action 5.1. Additional funds will also be required during the life of the recovery plan to contract a botanist to undertake the work on an as needs basis and in the first year of recovery to engage a suitably qualified and experienced contractor to develop threatened Caladenia hand-pollination guidelines and protocols as a reference for land managers and volunteers. State government agencies will cover the costs of salaries of regional staff responsible for on-going hand-pollination.

4.2 Harvest and store seed

Caladenia taxa produce capsules containing tens of thousands of microscopic seeds. Low levels of recruitment in the face of such high seed production suggests germination rates are low and/or plants fail to progress beyond protocorm or seedling stages. Information collected to date indicates that a high proportion of Caladenia seed may be predated by invertebrates and soil biota, presumably during summer (F. Coates, Parks Victoria, unpubl. data).

A percentage of the seed bearing capsules from each population of endangered Caladenia taxon will be harvested annually in late spring and re-released back onto the collection site (in the vicinity of existing plants) in late summer-early autumn. The number of capsules harvested will depend upon total capsule numbers and will be assessed on an annual basis when population monitoring occurs. Additional capsules will be collected for cryogenic storage and ex situ cultivation (see Action 7).

Seed will be dried and stored at RBG, UMILFR, SHSA or other suitable facilities over summer until required for use. This action will be the responsibility of state department staff and/or volunteers, however funds are required for the life of the recovery plan to engage a contractor to undertake the work on an as needs basis and to pay for the cost of cryogenic storage consumables.

4.3 Manage microhabitat

Recent trials indicate that good seedling germination of endangered Caladenia taxa can be achieved by microhabitat management (C. Beardsell, unpubl. data, A. Govanstone and A. Pritchard, unpubl. data.). A number of techniques for C. amoena, C. audasii, C. hastata and C. rosella have been developed that will be trialed with other endangered taxa as part of this recovery plan.

Examples include careful hand weeding, seedbed establishment and scattering of leaf litter around plants and the watering of plants during extended dry spring periods. Sites will be visited at least three times a year. The techniques adopted will be decided on a case-by-case basis and further techniques will be developed and implemented through an experimental approach.

Funds are required in the first three years of recovery cover the salary of a project officer to carry out the work and to train state department staff and volunteers who will be responsible for on-going microhabitat management. Travels costs will be covered by Action 5.1. Initially work will focus on endangered taxa (C. amoena, C. audasii, C. fragrantissima ssp. orientalis, C. hastata, C. lowanensis, C. robinsonii, C. rosella, C. thysanochila and C. xanthochila) and vulnerable taxa where populations are critically low (C. formosa at Beear (Victoria) and Mt Scott (South Australia)). Funding will also be required for the life of the recovery plan to contract expert botanists to undertake microhabitat management on an as needs basis. Funds are also sought in the second year of recovery to engage a suitably qualified and experienced contractor to develop microhabitat management guidelines and protocols as a reference for land managers and volunteers. NRE-PFF will coordinate the action and liaise with all relevant land managers as required.