Division Recovery objective 2: Understand the bio - Environment Protection and Biodiversity Conservation (National Recovery Plan for the Wollemi Pine (Wollemia nobilis)) Instrument 2025 - Recovery objective 2: Understand the biology of Wollemi Pine and associated species in its natural habitat to inform conservation of the species and its habitat | Zoe
Environment Protection and Biodiversity Conservation (National Recovery Plan for the Wollemi Pine (Wollemia nobilis)) Instrument 2025
Recovery objective 2: Understand the bioRecovery objective 2: Understand the biology of Wollemi Pine and associated species in its natural habitat to inform conservation of the species and its habitat
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Recovery objective 2: Understand the biology of Wollemi Pine and associated species in its natural habitat to inform conservation of the species and its habitat
Performance criterion 10.2.1 Aspects of the stand dynamics of the Wollemi Pine are documented and the age structures of the standing trunks in known stands are estimated. Ecological data gained is used to modify the management program outlined in Section 10.1 and assists in the tasks outlined in Section 10.3 and 10.4.
The stand dynamics of the Wollemi Pine were documented in a peer reviewed scientific paper, which described evidence for the Wollemi Pine having a recruitment strategy of maintaining a juvenile bank (Zimmer et al. 2014). This study highlighted the rarity of recruitment events, and hence the importance of protecting all seedlings and juveniles. Size structures of the standing trunks (diameters at breast height) were documented in 2003 and 2013. Growth rates have not yet been reliably estimated; hence, ages have not been estimated.
Monitoring has been ongoing at the wild stands since 1995. At Stand 1, each individual seedling, juvenile and mature tree stem greater than or equal to 2 cm DBH was tagged. Results of pre-fire monitoring of seedling and juvenile growth and survival at Stand 1 are presented in Zimmer et al. (2014). The majority of seedlings were killed in the 2019–20 fire and tags on individual coppice stems at Site 1 were lost. However, since 2020, fire-resistant tags have been applied to all stems greater than or equal to 2 m tall on all accessible juvenile and mature trees across all four wild sites, the relative positions of stems on individual trees mapped, and stem height, DBH and reproductive status recorded (Mackenzie, Clarke and Auld, unpubl. data). Canopy photography is also utilised to monitor tree health and major changes in canopy cover and structure.
Performance criterion 10.2.2 The fire history of the sites and impact of fire, rock-fall and wind shake on Wollemi Pines is examined. Key gap forming processes are identified. This information is used to modify existing management practices outlined under Section 10.1.
Field surveys of the wild Wollemi Pine population after the 2019–20 bushfires revealed that most adult trees survived the fires with their upper canopies intact (Mackenzie et al. 2021). Of the fire-affected trees greater than or equal to 2 m tall, two-thirds suffered partial canopy loss and one-third (predominantly juvenile trees) were completely top-killed (Mackenzie et al. unpubl. data). Of these top-killed individuals, approximately one-third were killed outright with the remainder (c. 20% of the post-fire population) reduced to vulnerable basal resprouts (Mackenzie et al. unpubl. data). The pre-fire bank of seedlings and smaller juveniles less than 2m tall has been 92–95% eliminated with only 4–7% of pre-fire individuals successfully resprouting (Mackenzie et al. unpubl. data). However, the juvenile bank is expected to re-establish from seed over the next 20-30 years (Mackenzie et al. 2021).
Earlier experimental studies of the impact of fire (under nursery conditions) on Wollemi Pines and three co-dominant rainforest angiosperms found that that cultivated cuttings of all four study species had the capacity to resprout after a single, low intensity fire.
There have been no further studies into rock fall or windshake.
Field observations suggest fire, rock fall and wind are likely to be the main canopy gap forming processes, along with natural senescence of dominant trees.
Performance criterion 10.2.3 Qualified individual/s are found to initiate a study/studies to increase understanding of evolutionary history of Wollemi Pine.
The evolutionary history of the Wollemi Pine has been well studied, including by Gilmore and Hill (1997), Stefanovic et al. (1998), Setoguchi et al. (1998), Liu et al. (2009) and Escapa & Catalano (2013).
Performance criterion 10.2.4 New techniques for the analysis of population genetics are investigated and, where appropriate, applied.
The chloroplast genome of the Wollemi Pine has been sequenced (Yap et al. 2015). Whole-chloroplast analysis has revealed low but detectable genetic diversity (Greenfield et al. 2016). More refined population genetic studies, based on reduced representation genome sequencing approaches are currently in progress, but preliminary analyses have detected low-level variation within and between subpopulations (Bragg et al. unpubl., Stevenson et al. 2023 preprint). These data are being used to guide the development of ex situ collections and translocated populations to maximize their genetic diversity (Mackenzie et al. 2021).
Performance criterion 10.2.5 Embryology and cone production cycles are better understood providing information for establishing evolutionary relationships within Araucariaceae and enabling estimation of seed production in different years. Knowledge gained is used to modify the management program outlines in Section 10.1.
Inter-annual variation in cone production was described by Zimmer et al. (2015a). Evolutionary relationships within the Araucariaceae have been explored, mainly using genetic analysis (see Performance criterion 2.3). Further research into the embryology of the Wollemi Pine is required.
Performance criterion 10.2.6 Knowledge of species associated with the Wollemi Pine and its habitat is gained and this information is used in the management of the wild population (Action10.1).
The rainforest community of the Wollemi Pine was described in detail by Benson and Allen (2007).
The soil microbiota associated with the Wollemi Pine was described by Rigg et al. (2016a).
Performance criterion 10.2.7 Potential habitat is identified and field searched.
Potential habitat for Wollemi Pine has been modelled, based on environmental characteristics such as geology, climate, vegetation type and fire history. However, the highly remote and dissected nature of the Wollemi National Park landscape meant that there were limited on-ground data to inform these models, leading to uncertainty in the reliability of predicted habitat.
Extensive helicopter and ground surveys have been undertaken within Wollemi National Park, and no additional stands have been found.