Feedback for NSW Central Coast Development Plan

NSW Central Coast orchids subject to a strategic biodiversity assessment

Guy Dutson (guydutson@gmail.com) & Bruce Smith

Orchid taxa listed as threatened under the Commonwealth Environment Protection and Biodiversity Conservation (EPBC) Act and analogous State Acts must be considered when assessing applications to clear vegetation or cause other significant impacts. Such development assessments are usually considered on a case-by-case basis and often conclude that the impacts to any listed species are insignificant and are permitted, leading to the concern of ‘death by a thousand cuts’ as the geographic range of species is progressively lost. Where impacts are considered to be significant, the steps of avoiding and minimising impacts are often under-prioritised, leading to a default of purchasing offset sites for the species and/or its vegetation community. Biodiversity offsets are contentious for many reasons, especially because they have a track record of under-delivery, further exacerbating the loss of populations and decline of species. Strategic biodiversity assessments aim to overcome some of these deficiencies by considering the cumulative impacts over a larger spatial area and designing aggregated (and often better managed) offsets. Here, we discuss one current example and offer opportunities for readers to contribute to its scientific rigour.

The NSW Central Coast supports three endemic orchid species: Genoplesium [Corunastylis] branwhiteorum (Plate 1), G. [C.] insigne (Plate 2) and Thelymitra adorata (Plate 3) which are listed as Critically Endangered under the EPBC Act and NSW Biodiversity Conservation Act (BC Act). All are mostly restricted to an area proposed for large-scale residential development and consequential habitat clearance. To assess and address these impacts, the NSW government is undertaking the Central Coast Strategic Conservation Plan (hereafter, ‘the Plan’). This is a strategic biodiversity assessment that will pre-authorise development under the relevant biodiversity legislation subject to various conditions (including the need for assessment against other non-biodiversity considerations). This article greatly simplifies the detail, for which please see the Central Coast Assessment Report and other documents exhibited on https://www.planningportal.nsw.gov.au/draftplans/exhibition/have-your-say-draft-plan-central-coasts-urban-growth-and-environment until 11 November 2025.

The Plan aims to completely avoid impacts to these three Critically Endangered orchids. Mechanisms include the requirement for orchid surveys prior to development and, if any of these species are found, planning controls including a 60 m buffer, regulated fire, stormwater and weed management in the vicinity and specific controls for roadside management. For two additional orchid species listed as Vulnerable, Cryptostylis hunteriana and Diuris praecox, offsets will be required based on expert modelling of suitable habitat.

The Plan is based in legislation and does not consider taxa not listed under the relevant Acts. For example, a number of taxa or variants informally known as Calochilus “pharus Branwhite ms.” (Plate 4), Calochilus “golden” (Plate 5), Thelymitra sp. aff. simulata (Plate 6) and Thelymitra sp. aff. atronitida (Plate 7) are likely to occur in the impact area but are not assessed under the Plan.

Strategic assessments offer the advantages that coordinated surveys and cumulative impact assessments can better identify key sites and enable the planning of conservation areas and corridors (including non-developable land and offset sites), and mitigation requirements can be standardised. Strategic assessments, or at least the concept of ‘go’ and ‘no-go’ areas are likely to be used increasingly in environmental impact assessment in Australia.

ANOS members with knowledge of orchid survey and conservation requirements are encouraged to review the Plan’s survey methods and proposed conservation actions for these species (e.g. Chapter 27.2 of the Central Coast Assessment Report) and submit any proposed revisions. For example, the size of buffer required between orchids and residential development and the risk of false negatives when following statutory survey guidelines are probably based more on expert opinion as much as empirical evidence. Hopefully, this Plan can set a sound precedent for future strategic biodiversity assessments elsewhere in Australia. It also acts as a reminder of the value of elucidating the taxonomic status of variants and listing threatened rare orchids under Commonwealth and State legislation.

Plate 1: Genoplesium [Corunastylis] branwhiteorum © Bruce Smith

Plate 2: Genoplesium [Corunastylis] insigne © Bruce Smith

Plate 3: Thelymitra adorata © Bruce Smith

Plate 4: Calochilus “pharus Branwhite ms.” © Bruce Smith

Plate 5: Calochilus “golden” © Bruce Smith

Plate 6: Thelymitra sp. aff. simulata © Bruce Smith

Plate 7: Thelymitra sp. aff. atronitida © Bruce Smith