Amended Noosa Project Restoration Plan V12_5

SECTION 2 – RESTORATION MODELS
Habitat and restoration suitability modelling are analytical techniques used to select broad restoration
zones and local restoration sites that are suitable for oyster ecosystem restoration within an estuary.
It is within the restoration sites that restoration substrates (in this case principally rock riprap) is
placed to form the foundation of new oyster beds.

2.1 Habitat suitability

Where shellfish ecosystem restoration is conducted often determines how successful an effort is. In
Noosa, TNC used standardized habitat suitability indices and geospatial decision support tools to
confirm the suitability of the Noosa River estuary for oyster ecosystem restoration.

Known environmental and biological criteria of the dominant rock oyster species, Sydney Rock Oyster
(Saccostrea glomerata), were compared with the physical parameters of the estuary (i.e. bathymetry,
salinity, temperature, dissolved oxygen,). Areas of the estuary which are suitable for rock oyster
restoration were then rated for their suitability (Table 2.1) and presented, geospatially, in the Habitat
Suitability Model (Figure 2.1).

While the Habitat Suitability Model indicates that large areas of Lake Doonella and Lake Weyba would
be suitable for rock oyster restoration, practically, this would not be the case (as per the Restoration
Suitability Model presented further on in this submission). Further challenges in the lakes include high
sediment loads, high retention of suspended sediments after storms and low flow regimes. These
possible limitations would need to be tested as part of Phase II restoration works.

Table 2.1: Habitat suitability parameters and criteria for Sydney rock oysters

 PARAMETER      ENVELOPE     CRITERIA        Rationale                          Source
                             (more
                             suitable = 4,
                             less = 0)
 Bathymetry     0-9 m        0-9m = 4        Within ecological tolerances.      (Powers et al. 2009, Gillies et
                             >9m = 0         Below LAT weighted higher as       al. 2018)
                                             subtidal restored oyster
                                             ecosystems have been seen to
                                             perform better than intertidal
                                             ecosystems.
 Salinity Av    25-35ppt     35-30=4;        Within ecological tolerances.      (Nell and Gibbs 1986, Nell
                             30-25=3;        Lower salinities scored lower as   and Holliday 1988, Holliday
                             <25=0           linked to outbreaks of the         1995, Dove 2003, Butt et al.
                                             protozoan parasite QX              2006, Dove and O’Connor
                                             (Marteilia 16ydney).               2007, Diggles 2013,
                                                                                Schrobback et al. 2014)
 Temperature    8-29C        8-24C= 4;       Within ecological tolerances.      (Holliday 1995, Butt et al.
 Max                         24-28 = 2;      Temperatures above 28 °C           2006, Diggles 2013,
                             >28=0           scored lower as linked to          Schrobback et al. 2014,
                                             outbreaks of the protozoan         Snyder et al. 2017)
                                             parasite QX (Marteilia sydneyi).
 DO Av          >4mg/L       >4mg/L = 4;     Within ecological tolerances.      (Schrobback et al. 2014)
                             <4mg/L= 0


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