Calochilus pulchellus is endemic to NSW and Victoria, Australia. The main factors that make the species eligible for listing in the Endangered category are its restricted area of occupancy (68 km²), small known population size (300–500 individuals), and projected continuing decline in area, extent and quality of habitat. The main current threats to the Pretty Beard-orchid include fire regimes that cause declines in biodiversity (inferred), trampling and illegal collection (observed/suspected), grazing by feral deer (suspected) and climate change (projected).

The Pretty Beard-orchid is known to occur in the Shoalhaven region of New South Wales (NSW) with a disjunct subpopulation discovered in 2020 near Wingan Inlet in eastern Victoria (Vic). Further information can be found in the species conservation advice (DCCEEW 2022).

There are approximately 231 known plants: 180 in NSW and 51 at the single known subpopulation in Victoria (Backhouse pers. comm. 27 May 2021). In 2011, the known population size was approximately 30 individuals from four subpopulations (Stephenson 2011). The increase in the number of subpopulations and plants is attributed to targeted survey effort in the Shoalhaven region (Towle et al. 2020) and the chance discovery of the species in Vic. The targeted surveys in 2019 located 89 individuals at previously unknown locations, from a survey effort of 56 person hours across four days, including 76 km of transects corresponding to ~28.4 ha of transect survey area (Towle et al. 2020). Further targeted surveys in 2020 located an additional 12 individuals at previously unknown locations, from a survey effort of 89 person hours across six days, including 111 km of transects and ~33.7 ha of transect survey area (Ecoplanning 2021). The Pretty Beard-orchid was not detected at four of the six new locations surveyed in 2020 (Ecoplanning 2021).

Reproductive ecology 
The life cycle of the Pretty Beard-orchid follows the typical pattern of native herbaceous (seasonally dormant) terrestrial orchid species. Plants are dormant from summer to early autumn, when dormancy is broken in response to rainfall and decreasing temperatures (Jones 2021). Leaves emerge in autumn and have been observed above-ground in late April (Coutts-McClelland pers. comm. 7 December 2021). Flowering occurs from late October to late November, and flowers generally remain open for only a few days with one or two flowers on the inflorescence open at a time (Jones 2021). Flowering material is required for positive identification.

Pollination in Calochilus is by sexual deception of male scoliid wasps from the genus Radumeris (previously Campsomeris) that are likely attracted to the flowers by chemical and visual stimuli (Bower and Branwhite 1983). Recent observations indicate the Pretty Beard orchid is pollinated by male Radumeris sp. wasps that attempt to copulate with the labellum (Newby pers. comm. 8 December 2021; observations conducted by DPIE and RBGSYD, manuscript in prep.). Most Calochilus species are receptive to pollinators for one or two days, after which the flower begins to close and self-pollination occurs (NSW TSSC 2008, Jones 2021).

Fruits take at least seven weeks to mature following pollination (Coutts-McClelland pers. comm. 7 December 2021). Each mature capsule contains thousands of minute seeds that are dispersed by wind when the capsule dehisces. After flowering, plants senesce to their subterranean tubers. Unlike some terrestrial orchids, tubers are not replaced annually by daughter tubers, and thus reproduction is only from seed (Jones 2006 cited in Towle et al. 2020, Jones 2021). The minute seeds carry little nutrients, and infection by mycorrhizal fungi from the genus Tulasnella is required for successful seed germination to occur (Warcup 1981).

No data are available regarding the life cycle, generation time, length of juvenile period or plant longevity for the Pretty Beard-orchid, although terrestrial orchids are generally long-lived (Shefferson et al. 2020). One plant at Vincentia has been observed emerging for seven consecutive years since formal monitoring began in 2015 (including three times as a leaf only and four times as a flowering stem) and another plant was observed flowering for five consecutive years since it was found (Coutts-McClelland pers. comm. 1 Mar 2022). Towle et al. (2020) recorded a single plant at Woollamaia Nature Reserve 20 years after the previous record (also of a single plant), but it is not clear whether these records represent the same individual.

Habitat ecology
The Pretty Beard-orchid has been traditionally known to occur primarily in wet heathy habitats, often in association with damp soils in swamps or swamp margins with high moisture availability (Jones 2006, NSW TSSC 2008). More recently, the species has also been discovered growing in woodlands, often in association with deep leaf litter at the base of large trees such as Eucalyptus racemosa (Narrow-leaved Scribbly Gum) and Corymbia gummifera (Red Bloodwood) (Towle et al. 2020). Further information on habitat can be found in the species conservation advice (DCCEEW 2022).

Fire ecology
The Pretty Beard-orchid is reported to exhibit a strong positive flowering response following summer bushfires (Jones 2021). Summer fires during the dormant period are unlikely to directly impact orchid tubers which are situated well below the soil surface, and instead may remove competition from other plants and release nutrients into the soil, thereby promoting flowering.

However, out-of-season fires that coincide with the active growing period are known to be a threatening process for many terrestrial orchids (Weston et al. 2005; Jasinge et al. 2018a, b), including species that typically flower well following summer bushfires (Jasinge et al. 2018a). Fires during the active growing period (typically autumn to spring) may result in loss of vegetative material before sufficient starch reserves can be built up through photosynthesis, or recovered through resorption at the end of the growing season. For example, fires early in the growing season (i.e., autumn and winter) of two terrestrial Australian orchids resulted in far fewer plants emerging the following year compared to late spring or summer fires (Jasinge et al. 2018a). In other tuberous plants such as Tribonanthes, Utricularia and Burchardia, plants resorb much of their above-ground dry matter (in the order of 50–80 %) back into the tuber at the end of the growing season, and a similar process is likely to occur in terrestrial orchids (Pate and Dixon 1982). Therefore, fires during the growing season of terrestrial orchids are likely to lead to a loss in carbohydrate production and nutrient recovery, leading to a decline in tuber starch reserves. Repeated fires during the growing season without adequate recovery may lead to population decline.

In May 2017, an ecological burn was undertaken at the Little Forest Plateau type site (Coutts-McClelland pers. comm. 24 June 2021). When the species was first collected at Little Forest Plateau in 2004, 14 plants were observed, but no plants were found during searches in 2015 and 2016 preceding the May 2017 burn (Coutts-McClelland pers. comm. 24 June 2021). No plants were observed during subsequent post-burn surveys in 2017 and 2018 (Coutts-McClelland pers. comm. 24 June 2021), but seven plants were observed in 2019 (Towle et al. 2020) and 45 plants were observed in 2020 (Coutts-McClelland pers. comm. 24 June 2021). The subpopulation was not burnt in the 2019–20 bushfires. Although no plants were observed in the two years following the ecological burn, rainfall is a confounding factor in interpreting the impacts of out-of-season fire in this subpopulation, as terrestrial orchids typically flower well in years with good rainfall, and can be difficult to locate when not in flower in dry years (Janissen et al. 2021). Rainfall in the Shoalhaven region was low in the years 2004 and 2017–2018, whereas rainfall in 2019 was slightly below average but with good rain in the winter (June) preceding flowering and rainfall in 2020 was above average (Towle et al. 2020; Bureau of Meteorology 2022). Given the available information, it is not possible to draw definitive conclusions about the flowering response of the Little Forest Plateau subpopulation to the May 2017 ecological burn.

The main threats to the Pretty Beard-orchid are listed, including threats known to be currently operating, recent historical threats, and projected future threats. The main current threats to the Pretty Beard-orchid include fire regimes that cause declines in biodiversity (inferred), trampling and illegal collection (observed/suspected), grazing by deer (suspected) and climate change (projected). Urban development has been observed to impact the species in 2008, although most known subpopulations are now within national parks or reserves, with the exception of Vincentia (south) where plants occur on private property that is in the process of transferral to national park, one plant (Naval College Rd) on private property that is threatened by development, and 19 plants on private property near Hyam’s Beach. Timber harvesting (suspected) is a potential threat to the species, as the Victorian subpopulation occurs in close proximity to state forest, and potentially suitable habitat exists in areas subject to timber harvesting pressures in eastern Vic and southeast NSW. Climate change (projected) is projected to lead to increased temperatures, changes in rainfall patterns and an increased risk of fire danger weather and extreme events, which in turn may negatively impact flowering and recruitment, growing period and habitat quality. In addition, there are several minor or potential threats to the Pretty Beard-orchid that are not included. Grazing by stock has been observed to impact the only known plant at Naval College Rd (Stephenson 2015). Grazing is likely to have degraded habitat at this site, although the species may still persist underground. However, grazing by stock is unlikely to be a threat to plants at other sites, and is therefore not included. Phytophthora cinnamomi is confirmed to be present at Vincentia (south), but it is unknown what impact (direct or indirect) this pathogen is having on the species (Coutts-McClelland pers. comm. 24 June 2021). Grazing by invertebrates and suspected macropods has been noted at the Vincentia subpopulation (Coutts-McClelland pers. comm. 21 February 2022), and is likely to occur at other sites. However, it is unclear whether rates of herbivory are high, and further research is needed to determine whether herbivory from invertebrates and macropods is likely to pose a threat to the species. Lack of pollination is a threat for many orchids with specialised pollinator interactions, including species that sexually attract male insects (Reiter et al. 2017, Phillips et al. 2020). However, most Calochilus species self-pollinate if they aren’t pollinated by insects within the first few days, and the Pretty Beard-orchid has been observed to have a high rate of natural fruit set (Coutts-McClelland pers. comm. 21 February 2022), suggesting that the Pretty Beard-orchid is likely to be able to set seed in the absence of pollinators.

Indigenous Australians have a long and profound history of management of the country on which the Pretty Beard-orchid occurs. The Pretty Beard-orchid is known from six subpopulations where the rights of Traditional Owners are managed by the Ulladulla and Jerringa Aboriginal Land Councils in New South Wales (New South Wales Aboriginal Land Council 2021). Traditional Owners have not been formally recognised for the Victorian subpopulation (Aboriginal Victoria 2021). Although there is no published information on cultural significance of the Pretty Beard-orchid, other orchid species are culturally significant plants for Indigenous Australians, with their tubers used as a food source (Australian National Botanic Gardens 2007). Ascertaining the cultural significance of this species is identified as a priority action in the Conservation and Recovery actions.

Conservation and management priorities

Habitat loss disturbance and modifications

• Complete the transfer of the Vincentia (south) site into Jervis Bay National Park and investigate the possibility of inclusion of other unprotected habitat into the public conservation estate.
• Ensure locations of subpopulations are kept updated on state databases, in particular those used by fire and land management agencies. Ensure the precise location of subpopulations is not publicly available.
• Avoid undertaking planned burns of the species or its habitat during the species’ growing season (mid-autumn to early summer) and ensure habitat quality is not compromised as a result of any burn including appropriate post-fire monitoring and weed and herbivore control.
• Prevent trampling at Little Forest Plateau and recreational access to Vincentia (south) by installing access barriers or fences, where appropriate.
• Determine potential habitat for the species in the NSW and Vic forestry estate. Undertake pre-harvest surveys for the Pretty Beard-orchid in areas of suitable habitat designated for forestry activity and implement 100 m buffer exclusion zones from any forestry activity around all subpopulations.
• Conduct post-harvest surveys (>3 years after clearing) in areas of potentially suitable habitat in the NSW and Vic forestry estate, particularly along trails, to determine if the species is capable of colonising disturbed areas.

Herbivory

• Encourage the removal of stock from the private property site at Vincentia (Naval College Road). Grazing, although likely to degrade the habitat of the species, may not necessarily kill the orchid, and as such, this subpopulation should still be considered extant even if the orchid is not observed for lengthy periods of time (as the species has been shown to persist without detection for 20 years at Woollamaia Nature Reserve).
• Protect individuals from browsing by feral animals and macropods (including discrete caging of individuals or fencing of habitat) where necessary. Consider caging individuals post-fire if herbivores are likely to be present in the area.
• Control deer populations when there is evidence of their presence.

Disease

• Implement Phytophthora cinnamomi management plans to ensure that:

1. The pathogen is not spread within the wild population (part of which is already infected) as far as can be avoided (DOEE 2018)
2. Mitigation measures (e.g., treatment with phosphite (phosphonate)) are implemented if required and monitored for any signs of phytotoxicity.

Ex situ recovery action

• Continue and maintain seed collection and fungal symbionts for ex situ seed banking, with periodic testing of seed viability through germination testing, as per the Plant Germplasm Conservation Guidelines (Martyn Yenson et al. 2021). Consider caging inflorescences prior to seed collection, to ensure they are not impacted by herbivores.
• Develop ex situ propagation methods and, if appropriate, translocations in accordance with the Guidelines for the Translocation of Threatened Plants in Australia (Commander et al. 2018). Propagation of other Calochilus species in ex situ cultivation has proven difficult (Wright et al. 2006) and ex situ propagation methods for this species are currently the subject of a research project by the Australian Botanic Garden Mount Annan.
• Where translocations are used, monitor all translocated individuals to maturity, seed set and recruitment to ensure they are viable and are contributing to a reduction in the extinction risk for the species.

Climate change

• Map the exposure of the species to climate change using distribution modelling and climate change projections, to locate existing habitat patches and identify future habitat that would be suitable for the species under future climate change scenarios.
• Identify climate refuges suitable for translocation, ensuring some are geographically distant enough to increase the number of the locations of the species (see “Ex situ recovery actions”) if suitable habitat exists elsewhere. Where translocations are used, monitor all translocated individuals to maturity, seed set and recruitment to ensure they are viable and are contributing to a reduction in the extinction risk for the species.
• Undertake vulnerability assessments of the species’ sensitivity and adaptive capacity to changing climate conditions, which draw from genetic, physiological or ecological evidence.

Stakeholder engagement/community engagement

• The Pretty Beard-orchid is currently included in the NSW Saving Our Species Program, which has facilitated increased survey and management actions. Inclusion in such programmes should be supported.
• Engage and involve Traditional Owners in conservation actions, including surveying for new populations and management actions.
• Liaise with the local community and government agencies to ensure that up-to-date population data and scientific knowledge inform the implementation of conservation actions for this species and, where appropriate, orchid conservation groups.
• Engage community groups by encouraging participation in surveys for the species, while limiting public knowledge of known subpopulations.
• Inform landowners and managers of sites where there are known populations and consult with these groups regarding options for conservation management and protection of the species, including the removal of grazing pressures.
• Ensure land management is sympathetic to the long-term requirements of the species and where possible negotiate land management agreements.

Survey and monitoring priorities

• Further surveys are a priority for this species. Conduct targeted surveys throughout the range of the Pretty Beard-orchid to better determine its population size. Surveys could investigate the large area between the known NSW and Vic subpopulations, as well as further surveys near known subpopulations including on private property.

Maintain a monitoring programme to

• Determine trends in population size and distribution.
• Determine threats and their impacts; and,
• Monitor the effectiveness of management actions and the need to adapt them if necessary.

Information and research priorities

• Work with Traditional Owners to divulge any traditional knowledge associated with the species ensuring the practices to record, store and share this knowledge are mutually supported.
• Determine critical habitat for the Pretty Beard-orchid, including key microhabitat features that are important for the long-term survival of the species.
• Identify fire regimes, including fire season, that are detrimental to the species and those that allow population persistence.
• Investigate the impact of projected climate change-related threats (increase in the frequency and severity of fire and drought, increase in temperature and changes in rainfall patterns) on the suitability of habitat for the species.
• Continue investigations into propagation and ex situ propagation and growing methods for the Pretty Beard-orchid.
• Identify the pollinator(s) of the Pretty Beard-orchid and investigate its biology and ecological requirements, including its abundance in the landscape. Confirm that Pretty Beard-orchid flowers are capable of setting seed if pollinators are not present.
• Identify which mycorrhizal partners are required for germination of the Pretty Beard-orchid, including their abundance in the landscape.