2022-11-08 P&E Agenda - Item 6 - Attachment 1 - Current & Historical Distribution of Seagrass in the Noosa Estuary (40 pages)

                                                            Ecological Service Professionals
                                                                               Sustainable Science Solutions




understand the impact of this change on the potential suitability of habitats for seagrass,
particularly in Weyba Creek and along the main river channel.
Seagrass meadows around the globe are sentinels for change in the environment. They are
primary producers, capable of engineering the environment by converting sunlight, nutrients
and carbon from the environment to stabilise soft sediments and create structured complex
habitats that support high biodiversity including fish and invertebrates of commercial
importance (Jelbart et al 2007; Nagelkerken et al. 2008; Waycott et al. 2011). The loss of
seagrass in Lake Cooroibah and along the Noosa River at Tewantin and around Goat Island
significantly decreases the potential ecological functions that seagrass can provide, including
filtering water and sequestering carbon in the Noosa Estuary. The loss of biological filtration
habitats such as seagrass, saltmarsh, mangrove and oyster reef habitats is not new in
Noosa, with the substantial loss of habitat occurring at Hays Island in the early 1970s. This
dramatic change to the mouth of Weyba Creek (Figure 5.1) may have altered water
movement and created conditions that favoured the persistence of seagrass in some areas,
and the decline in others. The loss of seagrass, particularly the large extent of loss from
within the lakes may have contributed partly to the reported the declines in availability and
therefore total catch of prawns in the estuary (Thurstan 2015); however, further work is
required to assess the links between loss of seagrass and declines in prawn catches in
Noosa. Elsewhere, seagrass beds are known to have a significant role as a nursery habitat
for prawns in estuaries and embayments (Skilleter et al. 2005).




Assessing Distribution of Seagrass in the Noosa Estuary                                              A-25