Document ID: chunk:federal_register_of_legislation:F2022L00775:reg:18:p4
Version: federal_register_of_legislation:F2022L00775
Segment Type: reg
Provision Reference: reg 18 (pt 4/152)
Character Range: 50151–53208

distributions in Australia.
Generally, effects of ENSO events on seabirds are seen first in the central Pacific where they develop and are the most severe, but parallel oceanographic and atmospheric changes occur in the Atlantic and Indian Oceans (Schreiber and Burger 2002). For example, during ENSO events, when the flow of the Leeuwin Current flow is weaker and the Southern Oscillation Index is low, reproductive effort and output was severely reduced for Lesser Noddy (Anous tenuirostris) and Common Noddy (A. stolidus) breeding at the Houtman Abrolhos, Western Australia (Surman and Nicholson 2009). The conditions appeared to result in low prey availability, which delayed the commencement of seabird breeding by up to two months and caused breeding failures (Surman and Nicholson 2009).
La Niña events can also impact seabirds. Cannell et al. (2012) observed negative impacts on breeding success and fledging mass of Little Penguin (Eudyptula minor) in Western Australia.

 Storms and cyclones
Small populations such as those of White-tailed Tropicbird (Phaethon lepturus), Kermadec Petrel (Pterodroma neglecta) and Little Tern (Sternula albifrons) are vulnerable to stochastic events such as storms and cyclones. Storms and cyclones have the potential to have serious effects on the arrival points, nesting substrate, vegetation and wildlife on remote seabird breeding islands, in addition to impacting seabirds directly at sea. Such natural factors can place additional pressures on seabird populations already adversely affected by anthropogenic influences. However, stochastic events such as storms and cyclones are beyond the control of management authorities and have not been addressed for the species in this Plan.

 Geological processes
 Volcanism
Active volcanoes generally occur close to the major tectonic plate boundaries. They are rare in Australia because there are no plate boundaries on this continent. However, there are two active volcanoes located 4,000 kilometres south west of Perth in the Australian Antarctic Territory on Heard Island and the nearby McDonald Islands.
Mawson Peak, on Heard Island has erupted several times in the last decade and remains active. The volcano on McDonald Island, after being dormant for 75,000 years, became active in 1992 and has erupted several times since, the most recent in 2005. It is estimated that volcanic activity displaced more than 1 million pairs of Macaroni Penguins (Eudyptes chrysolophus) on McDonald Island after the 1992 eruptions, though satellite images show unidentified penguins that may be recolonising the area (Crossin et al. 2013).

22 Wildlife Conservation Plan for Seabirds

Threats

The other active volcanoes nearest Australia are in Papua New Guinea, New Zealand, South Pacific, Indonesia and the Philippines. Gas-rich sticky magmas dominate the Asia Pacific, making composite volcanoes and calderas the most common varieties in the region. These types of volcanoes threaten lives, property, agricultural lands and livelihoods throughout south-east Asia