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




communities (Ferguson & Eyre 2013). These types of soft sediment (sand and mud) habitats
are the dominant habitat type within the Noosa Estuary.
Seagrasses are highly sensitive to changes in environmental conditions and declines in
water quality (particularly high turbidity) and are therefore considered indicators of
environmental degradation and natural stressors (Heck et al. 2008). As a result, their spatial
distribution can be highly dynamic, and large interannual changes in the extent of seagrass
habitats and community structure resulting from natural disturbances (e.g. flood events,
changes in rainfall) have been documented for example in the Moreton Bay region (Lyons et
al. 2015) and Great Sandy Strait particularly following extensive floods (Preen et al. 1995;
Campbell & McKenzie 2004).
In the Noosa Estuary, the most comprehensive and detailed historical mapping of seagrass
was completed in 1987, recording a total of 47 Ha of dense seagrass primarily in the Noosa
River to Lake Cooroibah and in Weyba Creek (Hyland et al. 1989). A further 923 Ha of
sparse and patchy seagrass was recorded, primarily (94%) in Lake Weyba (Hyland et al.
1989); however, the area of sparse and patchy seagrass is considered to be an overestimate
due to the sparse nature of and difficulty mapping from photographs at the time. There have
also been several small-scale surveys and monitoring programs completed at several sites
throughout the estuary using the established seagrass watch monitoring protocols through
Noosa Integrated Catchment Authority (NICA) (Seagrass Watch 2006; McKenzie & Yoshida
2013; NICA 2014; NICA 2016). These monitoring events were designed to assess long-term
changes in the coverage and species composition of seagrass along permanent transects
(McKenzie & Yoshida 2013). We are unaware of any broadscale assessment of the
distribution of seagrass in the estuary completed since 1987. The most recent monitoring of
seagrass was completed by NICA and USC researcher Dr Javier Lyon, which was used to
develop a method of monitoring the distribution of seagrass using aerial drone surveys and
photogrammetry (Lyon 2018).




Assessing Distribution of Seagrass in the Noosa Estuary                                                  2