26Wildlife Conservation Plan for Seabirds

26 Wildlife Conservation Plan for Seabirds

Prey depletion

Long-term demographic studies show that seabird populations may suffer from competition with fisheries (Bertrand et al 2012; Grémillet et al. 2018). Tuna fisheries are thought to have reduced prey availably for a number of procellariforms as many species rely on tuna to herd shoals of small fish to the surface where they become available for surface-feeding birds (Au et al. 1986; Furness 2003; Brooke 2004). Harvesting of marine resources can affect marine ecosystems and predator-prey interactions by the removal or redistribution of biomass central to pelagic food webs. In particular, fisheries targeting forage fish and euphausiids may be in competition with seabirds for food resources. Understanding this process is critical for the implementation of a whole of ecosystem approach to fisheries management.

Resource extraction

The effects of terrestrial mining can be profound and have direct consequences on seabirds and their habitats, or indirect impacts via disturbance or pollution. Guano mining in the 19th and 20th Centuries led to the human colonisation of many seabird breeding islands for so called ‘white gold’. Important island habitats were severely modified to fuel the demand for the highly effective fertilizer. Colonisation also spread invasive species which helped accelerate seabird declines on some islands. Even today, some historical guano mines have yet to recover from mining activities and will take hundreds of years to recover fully, if at all.

Whilst the impacts of tailings storage facilities mainly affect waterfowl and passerines, better knowledge of tailings dam ecology is required to develop site-specific monitoring and mitigation to better understand risks posed to wildlife, including seabirds (Smith et al. 2008). Solar-powered floating deterrent beacons with sonic guns have been trialled at ponds to deter species such as gulls and terns and some shorebirds (Read 1999). The Australian Government recommends monitoring of wildlife impacts and reducing the risks associated with the storage of water on tailings storage facilities, which could involve perimeter fencing, minimising the area of ponded water, netting or intermittent noise to distract birds (Commonwealth of Australia 2016).

The recently discovered breeding sites of Tahiti Petrel (Pseudobulweria rostrata) in New Caledonia are all in areas threatened by nickel mining (Spaggiari and Baré 2004, Delelis et al. 2007, Le Breton 2008), with mining activities predicted to have severe negative impacts on breeding success and potential adult mortality through ingestion of harmful materials. Threats such as these need to be minimised to avoid accelerating population declines.

Seabirds are known to aggregate around oil and gas platforms in above average numbers due to night lighting, flaring, food concentrations and other visual cues (Wiese et al. 2001). Bird mortality has been documented due to collision with the structure, oiling and incineration by the flares (Wiese et al. 2001). Implementing a comprehensive monitoring program of impacts of these offshore platforms should include nature, timing and extent of bird mortality caused by these structures. This information can then be used to better inform regulators responsible for exploration and extraction proposals.

Proposals for oil and mineral exploration and exploitation should be adequately assessed and, as appropriate, conditions imposed to ensure there are no adverse effects on seabirds or their habitats.

Wildlife Conservation Plan for Seabirds 27

Renewable energy

Marine renewable energy developments (MREDs) are becoming an increasing feature of the marine environment. MREDs are just one of several infrastructure developments in the marine environment that have the potential to impact seabirds. Globally, there is potential for generating energy from the marine environment in the form of extensive wind, wave and tidal-stream resources. However, the potential effects of MREDs on seabirds are not yet fully understood. Seabirds may be directly affected through collision with infrastructure or indirectly affected by displacement from foraging areas. A key question is how MREDs may affect seabird foraging success through changes in foraging behaviour and will be key to understanding whether large-scale installations could have impacts at a population level.

A key research area needed to address this issue is to better understand seabird distribution and foraging behaviour. This information will improve our understanding and be able to better predict adverse impacts in seabird populations.

Terrestrial windfarms in Tasmania have been reported to kill seabirds including diving-petrels, shearwaters, prions, storm-petrels and gannets from bird strikes (Hull et al. 2013). Species with large wingspans and relatively slow wingbeats are known to be susceptible to striking terrestrial windfarms, suggesting White-bellied Sea-Eagles, albatrosses and larger petrels may be at risk if offshore windfarms are constructed. Floating solar fields or deployment of solar fields over marine saltfield ponds and wastewater ponds may limit foraging opportunities for seabirds, conversely these may increase undesired roosting activity, fouling panels that may need mitigation.

Anthropogenic disturbance

Disturbance can be defined as any activity that changes the behaviour or physiology of one or more individuals within a colony (Gӧtmark 1999; Carney and Sydeman 1999; Nisbert 2000). Disturbance of seabirds causing adverse impacts can be classified in two broad categories: recreational disturbance and investigator disturbance (see reviews Gӧtmark 1999; Carney and Sydeman 1999; Nisbert 2000; Carey 2009). Recreational disturbance can be as simple as walking a dog on a beach close to nesting colonies of terns, causing them to flush off their nests. Investigator or researcher disturbance are activities affecting individual birds or nests such as marking nests, trapping, banding and handling of adults and their young.

Studies of breeding seabirds including gulls, shearwaters, penguins, boobies, gannets and cormorants have demonstrated that excessive disturbance can reduce reproductive success, reduce chick growth, disrupt feeding ecology and change physiological parameters (Gӧtmark 1999; Carney and Sydeman 1999; Nisbert 2000; Carey 2009). Efforts to reduce disturbance from recreational activities and researchers should be managed accordingly particularly when threatened species are involved or the breeding colony is small. For example, guidelines for visitors to seabird colonies in the Great Barrier Reef (GBRMPA 1997) and Macquarie Island (Tasmanian Parks and Wildlife Service 2018) have been developed to support tourist operations and researchers undertaking necessary biological investigations. GBRMPA have also developed guidelines for managing research in the Great Barrier Reef Marine Park (GBRMPA 2019).