Background/Aims
Murray Crayfish is the second largest freshwater crayfish in the world. Once common in the waters of the South Australian River Murray, the number of Murray crayfish declined to a point of virtual extinction in the 1980s as a result of overfishing, the effects of river regulation and declines in water quality. Improved understanding, extensive research and recent improvements to these conditions mean it’s now time to bring the is culturally significant species back to South Australia. Through this highly collaborative five-year project, Murray crayfish adults and juveniles have been released to a suitable reach of the River Murray as part of a landmark trial to reintroduce the iconic Australian species back into the South Australian River Murray.

Methods
This project was guided by comprehensive planning (informed by a successful interstate reintroduction) and collaboration to maximise the likelihood of success. Annual releases of 200 adult and 400 juveniles, reared in captivity, were undertaken. Acoustic telemetry and standard hoop net monitoring was undertaken to detect success of reintroductions. For the acoustic telemetry, a subset of reintroduced Murray crayfish were fitted with accelerometer tags annually and released amongst an array of acoustic receivers to evaluate activity patterns.

Results
Monitoring reveals that thus far reintroductions have been successful. During hoop net monitoring, both adults and berried females were sampled in the reintroduction reach. Through the use of acoustic telemetry, daily activity and movement patterns have been observed for three cohorts of 30 crayfish for up to 12 months post release - with over 2.5 million individual detections of the tagged crayfish. More than 80% of tagged crayfish were found to have established within the reintroduction reach post release and were detected for lengthy periods over the ensuing 12 months.

Conclusion
The reintroduction of Murray crayfish back into the SA section of the Murray River represents one of the most significant reintroduction projects ever conducted in South Australia. Building on more than a decade of research and planning, this long-term project provides the best possibility of re-establishment of a self-sustaining population of the species in South Australia.

Revegetation using native seed is a critical tool to support the restoration of severely degraded landscapes where natural regeneration is insufficient and seedling-focused plantings are either logistically unfeasible or too expensive to implement. However, current practices using native seed are largely constrained by three main factors: (1) seed supply and end-use bottlenecks reduce the availability and effective application of diverse native species in restoration; (2) ecological mechanisms, such as plant functional traits and soil microbial interactions, are poorly integrated into restoration strategies resulting in suboptimal restoration outcomes; and (3) comprehensive economic data linking economic costs to restoration outcomes is limited, hampering informed investment decisions and adaptive management on the ground. To build an evidence base for the improved use of native seed to restore native vegetation at scale, we assembled an interdisciplinary team including research experts from Western Sydney University, Macquarie University, and University of Tasmania alongside the revegetation practitioner-partner AirSeed Technologies in conjunction with the Royal Botanic Gardens Domain and Trust in Sydney. The core of our collaboration focused on the research and development of seed enhancement technologies and drone-facilitated precision seeding to improve biodiverse seed-based restoration at scale, while addressing broader challenges across native seed supply chains. This talk will present impactful findings from this collaboration, highlighting practical pathways to enhance the efficacy and scalability of native seed to restore biodiverse native vegetation.