National recovery plan for Twelve Threatened Spider-Orchid Caladenia R. Br. Taxa of Victoria and South Australia 2000 - 2004
James A. Todd
Department of Natural Resources and Environment, Victoria
Flora and Fauna Statewide Programs, March 2000
Action 3: Protect populations from high-risk threatening processes
Protection of populations from high-risk threatening processes will require a combination of broad-scale habitat management practices and finer-scale plant protection strategies. Wherever possible, the strategies adopted should aim to complement any other nature conservation objectives where these have been clearly defined as part of a current park or site management plan (Carr et al. 1993, Gordes and Gordes 1994, NRE 1996, Parks Victoria 1998).
3.1 Control high-priority weed species
Weed invasions represent a high risk threatening process to a number of different taxa (see Table 5) while weeds are a potential threat to all populations of all taxa. Generally, the risk posed by weeds is related to the size of the threatened Caladenia population, the number of sites at which the taxon is known and the biology, life form and population size of the weed species present. Caladenia taxa known from very few sites with low total population numbers are generally at higher risk of extinction from weed invasions. Examples include C. audasii, C. hastata, C. lowanensis, C. robinsonii, C. rosella, C. thysanochila and C. xanthochila.
In some cases, weed control will be achieved by adopting broad-scale habitat management approaches such as the periodic use of fire. In other cases, target species will need to be controlled using more direct methods. The use of standard weed control measures such as herbicide application and hand-pulling will need to be assessed against their potential impact on Caladenia populations and in some cases, alternative techniques may need to be developed. Weed identification and control plans will be prepared for each key population in the second year of recovery.
Funds are required in the first two years of recovery to cover the salary of a project officer to assist land managers with preparing weed control strategies for sites containing threatened Caladenia taxa. Weed species distribution and abundance data will be collected as part of Action 1.1 and travel and field expenses will also be covered under this action. Additional weed data already held on the Victorian Flora Information System will be made available as part of NRE contribution to the project. Funds are also sought in the first year of recovery to engage an expert weed-control contractor to develop protocols for land managers wishing to control weeds in highly sensitive areas containing threatened orchid taxa. The cost of weed control will be borne by the relevant land managers in years two to five inclusive. In some cases, volunteer labour through the use of Friends Groups will be used to undertake weed control (see Table 9).
|
|
C. amoena | C. audasii | C. formosa |
C. fragrantissima ssp. orientalis |
C. hastata | C. lowanensis | C. robinsonii | C. rosella | C. tensa | C. thysanochila | C. versicolor | C. xanthochila |
|
Action 3.1 |
X |
X |
X |
X |
X |
X |
X |
X |
X |
X |
X |
X |
|
Responsibility |
NRE-PFF/ PP, PV, land owners |
NRE-PFF/ NW, PV, COM |
NRE - PFF/ SW/Forests, EH |
NRE - PFF/ PP, PV |
NRE - PFF/ SW, PV |
NRE - PFF/ NW, PV, land owner |
NRE - PFF/ PP, Shire |
NRE - PFF/ PP, PV, land owners |
NRE - PFF/ NW, PV, EH |
NRE - PFF/ PP, Shire |
NRE - PFF/ NW/Forests |
NRE - PFF/ NW/Forests, Land owner |
|
Source |
2000 |
2001 |
2002 |
2003 |
2004 |
Total |
|
Total |
$22,060 |
$16,200 |
$14,700 |
$14,700 |
$14,700 |
$83,360 |
3.2 Control animal pests and predators and investigate grazing impacts
There are a number of animal pests and predators that pose a risk to the twelve threatened Caladenia taxa in Victoria and South Australia. Impacts include grazing by introduced and native herbivores, digging up of tubers by introduced Blackbird and the native White-winged Chough and predation of shoots and flowers by slugs, snails and other invertebrates.
Grazing by introduced and in some cases, native herbivores, has been identified as a high-risk threatening process for a number of threatened Caladenia taxa (see Table 5). In particular, those taxa that occupy grassy or herb-rich habitat and which also have a low total number of plants consisting of a few populations within a restricted range. Examples include C. amoena, C. audasii, C. lowanensis, C. rosella, C. thysanochila and C. xanthochila. Plant protection, using caging or fencing, has already been undertaken for a number of these taxa (see Table 9). For other taxa occupying habitat with heathy understoreys or with larger populations over a wider range, grazing represents a lesser threat to populations.
It is proposed that numbers of hares/rabbits and kangaroos/wallabies at various sites will be estimated using spotlight counts and dung pellet transects respectively (D. Morgan, University of Melbourne, pers. comm.). The results of these studies will help determine the risk posed by grazing at these sites and the methods required to control grazing impacts.
The threat posed by bird species and invertebrate species will need to be assessed on a site by site basis and control measures undertaken accordingly. Insect exclusion using cages and insecticide has been shown to greatly increase seed production and plant survival in rare plant species populations in the United States (Bevill et al. 1999) and similar techniques may need to be adopted for endangered Caladenia populations as part of the current recovery program. Techniques used for endangered orchid species elsewhere in Victoria include caging and baiting and these techniques will be adopted where necessary
For all sites containing threatened Caladenia taxa, there is a need to develop environmentally sensitive methods of pest animal control that minimise soil and site disturbance and control only target species. Both fine-scale and broad-scale techniques will need to be developed. This will be the responsibility of the state departments working in conjunction with the relevant land managers who will be responsible for on-ground pest animal control.
Funds are required in the first year of recovery for the supply and construction of urgent rabbit-proof fencing of C. xanthochila populations on private land at Murtoa and public land at Inglewood. Parks Victoria will control rabbits and fence smaller reserve areas containing threatened Caladenia taxa (eg. Kiata Flora Reserve, Glenlee Flora and Fauna Reserve).
Other areas within state forest will be fenced if required. Land managers will be responsible for undertaking pest animal control. State government departments will cover the costs of labour to conduct herbivore surveys and construct fences and regional staff time to assist with the development of pest animal management plans.
|
|
C. amoena | C. audasii | C. formosa |
C. fragrantissima ssp. orientalis |
C. hastata | C. lowanensis | C. robinsonii | C. rosella | C. tensa | C. thysanochila | C. versicolor | C. xanthochila |
|
Action 3.2 |
X |
X |
X |
X |
X |
X |
X |
X |
X |
X |
X |
X |
|
Responsibility |
NRE-PFF, PV, land owner |
NRE-PFF/ NW, PV, COM |
NRE - PFF/ SW/Forests, EH |
NRE - PFF/ PP, PV |
NRE - PFF/ SW, PV |
NRE - PFF/ NW, PV, land owner |
NRE - PFF/ PP, Shire |
NRE - PFF/ PP, land owner |
NRE - PFF/ NW, PV, EH |
NRE - PFF/ PP, Shire |
NRE - PFF/ NW/ Forests |
NRE - PFF/ NW, Land owner |
|
Source |
2000 |
2001 |
2002 |
2003 |
2004 |
Total |
|
Total |
$4,960 |
$3,250 |
$2,250 |
$2,250 |
$2,250 |
$14,960 |
3.3 Recover populations by fire and further investigate fire ecology
The inappropriate use of fire poses a risk to all threatened Caladenia taxa in southeast Australia. The preferred fire regimes for most taxa are poorly known but there is evidence that the population biology of some species may be heavily influenced by fire frequencies, season of burning, time since fire and fire intensity (Backhouse and Jeanes 1995).
Existing imposed fire regimes pose a high risk to several threatened Caladenia taxa at various sites (see Table 5). Examples include C. formosa, C. fragrantissima ssp. orientalis, C. hastata, C. robinsonii and C. thysanochila where the timing of past burns and in some cases, low fire frequency is placing populations at risk. Fire management plans will need to be prepared and implemented for these taxa. To assist with the preparation of these plans, a series of experimental fire regimes will be adopted for some taxa (eg. C. fragrantissima ssp. orientalis, C. hastata, C. lowanensis/tensa, C. robinsonii, C. xanthochila) and vital attribute data (sensu. Noble and Slatyer 1980, Tolhurst 1999) will be collected on the responses of threatened Caladenia taxa and a range of other plant taxa to these fire regimes. From this information, predictive models of species responses and successional patterns will be developed and appropriate fire regimes implemented (NRE 1999). Where possible, additional biotic and abiotic fire data will also be collected in accordance with guidelines for ecological burning (NRE 1999). Examples include site fire histories from the Victorian Integrated Fire Information System (Gordon Friend, NRE, pers. comm.), forest fuel loads, climatic data and fire intensity. The responses of threatened Caladenia taxa to unplanned wildfire will also be recorded where populations are affected. All data will be stored in the Victorian Vital Attributes Database held at the University of Melbourne and later included in the Victorian Integrated Fire Information System (K. Tolhurst, University of Melbourne, pers. comm.).
Funds are required in the first three years of recovery to cover the salary and associated travel/field costs (eg. vehicle hire, travel allowance, marker pegs) of a project officer to collect and collate vital attribute data on threatened Caladenia taxa and a range of other plant taxa following planned and unplanned fire events. Funds will also be required in years 4 and 5 to prepare fire management plans for key populations of all fire-dependent taxa. State department staff and volunteers will be trained in vital attribute data collection and they will be responsible for longer-term monitoring and data entry of burn sites. This information will be used to devise long-term fire regimes for these and related taxa in various habitats throughout southeast Australia.
NRE will be responsible for negotiating planned burns with the relevant land management agencies and/or land owners while burns will be implemented and conducted by NRE with the assistance of PV and the Country Fire Authority. NRE and PV will cover the salaries of regional staff used to assist with the collection of vital attribute data and conducting burns.
| C. amoena | C. audasii | C. formosa |
C. fragrantissima ssp. orientalis |
C. hastata | C. lowanensis | C. robinsonii | C. rosella | C. tensa | C. thysanochila | C. versicolor | C. xanthochila | |
|
Action 3.3 |
X |
X |
X |
X |
X |
X |
X |
X |
||||
|
Responsibility |
NRE - PFF/ SW/Forests |
NRE - PFF/ PP, PV |
NRE - PFF/ SW, PV |
NRE - PFF/ NW, PV |
NRE - PFF/ PP, Shire |
NRE - PFF/ NW, PV |
NRE - PFF/ PP, Shire |
NRE - PFF/ NW/ Forests |
|
Source |
2000 |
2001 |
2002 |
2003 |
2004 |
Total |
|
Total |
$5,470 |
$5,470 |
$4,000 |
$9,250 |
$9,250 |
$33,440 |
3.4 Control the spread of Cinnamon Fungus
Cinnamon Fungus (Phytophthora cinnamomi) generally poses a larger threat to sites containing a large proportion of heathland plant species and hence threat management will largely involve protecting sensitive and vulnerable heath and heathy woodland habitat from the effects of Cinnamon Fungus. Examples of such habitat include sites containing C. fragrantissima ssp. orientalis, C. hastata, C. robinsonii and C. tensa. The threat posed by Cinnamon Fungus to the twelve threatened Caladenia taxa is not well understood but there is anecdotal evidence to suggest that some Caladenia species may be sensitive to the fungus (Geoff Carr, pers. comm.).
At present, Cinnamon Fungus is not known to be present at any sites containing threatened Caladenia populations although hygiene measures have been implemented at the Betty Clift Conservation Reserve, Rosebud (C. robinsonii site) in an attempt to prevent its introduction to the reserve from nearby areas where it is known to occur (Backhouse et al. 1999).
Vulnerable habitat will need to be monitored annually to identify the presence of Cinnamon Fungus. Plant and soil material will need to be collected and analysed from sites suspected of containing Cinnamon Fungus. Infected sites will need to be quarantined and treated accordingly. Monitoring of sites for Cinnamon Fungus (and collection of plant material and/or soil samples) will be conducted during annual censusing of key populations (Action 5.1). Treatment and quarantine of infected areas will be the responsibility of the appropriate land manager.
Funds will be sought for the life of the recovery plan to cover the cost of analysis of plant and/or soil material from sites suspected of Cinnamon Fungus infection on an as needs basis.
| C. amoena | C. audasii | C. formosa |
C. fragrantissima ssp. orientalis |
C. hastata | C. lowanensis | C. robinsonii | C. rosella | C. tensa | C. thysanochila | C. versicolor | C. xanthochila | |
|
Action 3.4 |
X |
X |
X |
X |
||||||||
|
Responsibility |
NRE - PFF/ PP, PV |
NRE - PFF/ SW, PV |
NRE - PFF/ PP, Shire |
NRE - PFF/ NW, PV |
|
Source |
2000 |
2001 |
2002 |
2003 |
2004 |
Total |
|
Total |
$350 |
$350 |
$350 |
$350 |
$350 |
$1,750 |