Biodiversity - Turtles

The State Interest in Biodiversity: the endangered South-west Pacific loggerhead turtle is referenced in the State Planning Policy as one of the Matters of State Environmental Significance (MSES). 
Species Status - Loggerhead Turtle (Caretta caretta)

Loggerhead turtles are listed as endangered nationally under the Environment Protection and Biodiversity Conservation Act 1999 (Cth).  Loggerhead turtles are listed as endangered under the Nature Conservation (Wildlife) Regulation 2006 (Qld).

State Planning Policy defines matters of state environmental significance to include threatened wildlife under the Nature Conservation Act 1992 and special least concern animals under the Nature Conservation (Wildlife) Regulation 2006.

The Single Species Action Plan (SSAP) for the Loggerhead Turtle (C. caretta) in the South Pacific Ocean provides a framework to implement management actions to address the decline of loggerhead turtles in the south Pacific.

There is one genetic stock (management unit) for C. caretta in the South Pacific Ocean (Hatase et al. 2002; Dutton, 2007).  Almost the entire breeding for C. Caretta in the South Pacific Ocean occurs on beaches of the southern Great Barrier Reef islands and adjacent mainland of south Queensland and northern New South Wales of Australia and in New Caledonia (Limpus and Limpus, 2003; Limpus, 2008a); SSAP page 3.

The Recovery Plan for Marine Turtles in Australia confirms environmental status and protection under the EPBC Act and identified targets for interim and long term recovery: Australian Government, Canberra Department of the Environment and Energy (DoEE, 2017).

The south-west Pacific loggerhead turtle stock had declined from approximately 3,500 adult females nesting on the east coast of Australia to approximately 500 by 2000; DoEE, 2017 page 48.

Sunshine Coast Nesting Habitat

The beaches of the Sunshine Coast support habitat critical to survival of loggerhead turtles (C. caretta) which are the predominant nesting species, and green (Chelonia mydas) turtles, which nest in smaller numbers.  Although nesting numbers of both species are small compared to other nesting regions within Queensland (Limpus 2008), Australia's total annual population of nesting loggerheads in eastern Australia is made up of only approximately 500 females (Limpus & Limpus 2003), ~4% of which are known to nest on the Sunshine Coast (Sunshine Coast and Moreton Bay regional Council, benchmark artificial light at night (ALAN) survey, 2017, Pendoley Environmental Pty Ltd RTI17/023) page 2.

Climate Change increasing the importance of Sunshine Coast Nesting Habitat

Climate change is expected to drive changes in habitat conditions over a range of coastal environments, increasing temperatures and affecting shoreline erosion, advancing beach loss, and modifying tidal systems. Warmer temperatures will expand the current nesting range of turtle populations focused around rookeries further north into the Sunshine Coast region. (Sunshine Coast and Moreton Bay regional Council, benchmark artificial light at night (ALAN) survey, 2017, Pendoley Environmental Pty Ltd RTI17/023) page 48.

All species of sea turtles, sex is determined by incubation temperature during embryonic development (temperature-dependent sex determination, TSD). In sea turtles, cooler temperatures produce more male hatchlings while warmer temperatures produce more females; the incubation temperature that produces 50% of each sex is defined as the pivotal temperature. The pivotal temperature is heritable and varies among species and populations, but the transitional range of temperatures that produce 100% males or 100% females spans only a few degrees Celsius. Furthermore, extreme incubation temperatures not only produce female-only hatchlings but also cause high mortality of developing clutches. With warming global temperatures and most sea turtle populations naturally producing offspring above the pivotal temperature, it is clear that climate change poses a serious threat to the persistence of these populations (Jensen et al., 2018).

Threat – Light Pollution and Artificial Light at Night

Research informs us that artificial light is KNOWN to deter nesting turtles and brightly lit beaches discourage adult female turtles emerging from the ocean to nest onshore (Mattison, et al., 1993; Raymond, 1984b; Salmon, 2003).

 

Artificial light at night adjacent to marine turtle nesting beaches is disruptive to their breeding success (Salmon, 2003; Witherington and Martin, 2000).  Lighting located landward of the nesting beach, can negatively impact hatchling sea-finding, causing disorientation (inability to follow any consistent direction) and misorientation (non-sea-finding direction of travel) (e.g. Kamrowski, et al., 2014; Pendoley and Kamrowski, 2015; Tuxbury and Salmon, 2005) resulting in increased terrestrial exposure and consequent mortality. Brightly lit beaches may also discourage adult female turtles from leaving the ocean to nest onshore (e.g. Salmon et al., 2000):  (Sunshine Coast Council - Yaroomba development peer review Proposal, 2017, Pendoley Environmental Pty Ltd RTI18/002, 2017) Folio 8

 

Marine turtles have evolved to have two nocturnal stages in their critical breeding life history (Carr & Ogren 1960; Mrosovsky 1968; Limpus 1985; Gyuris 1993; Koch et al. 2008; Kamrowski et al. 2014b), which are sensitive to ambient lighting; adult nesting and hatchling sea-finding (Witherington & Martin 2000; Salmon 2003). Adult females will preferentially nest on darker beaches, meaning artificial lighting adjacent to the nesting beach can deter females from emerging to nest (Talbert et al. 1980; Salmon et al. 2000). In some cases, and dependent upon a range of natural and anthropogenic factors, artificial lighting has been shown to disrupt hatchling ability to locate the ocean after emerging from the nest in some cases because hatchlings use topographic and brightness cues for sea-finding (e.g. Mrosovsky & Shettleworth 1968; Salmon et al. 1992; Lohmann et al. 1997; Limpus & Kamrowski 2013; Pendoley & Kamrowski 2015).

 

Sunshine Coast Council engaged expert advice from both the Department of Environment and Science (DES) and Pendoley Environmental – Dr Kellie Pendoley in relation to the Yaroomba “Sekisui” development.  This information is now publically available on the SCC website (RTI18/002) and includes scientific references in the DES advice (01/02/2018), including “the basic principles regarding marine turtle nesting:

  • Turtles prefer to nest on dark beaches;

  • It is not just the immediate directly visible light sources that are creating the problems;

  • Bright sky glow without the actual light sources being visible can be disruptive to ocean finding behaviour of turtles many kilometres away from the light sources;

  • Bright light sources up to 18 km distant and directly visible can be disruptive to ocean finding behaviour”

AND

“Proposing a development within a few hundred metres of the nesting beach does not place the development footprint outside the range of potential lighting problems for the turtles. At Mon Repos, skyglow from the Bargara CBD 3 km away from the beach causes disrupted ocean finding behaviour of adult and hatchling turtles on moonless nights; illuminated Industrial development has been recorded causing altered ocean finding behaviour of flatback turtles at 18 km (Hodge et al. 2007).”

(Sunshine Coast Council - Yaroomba development peer review Proposal, 2017, Pendoley Environmental Pty Ltd RTI18/002) Folio 50 and Folio 53

 

This expert advice provided for the Yaroomba development is also applicable to all proposed developments adjacent the turtle nesting beach at Buddina.

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