*3.2. Image Interpretation*

At the high tide, marine and estuarine waters flood the bays, intertidal flats, and channels of the region which, during wet season events, are diluted to brackish levels in some areas by freshwater flooding and stream flow from the catchment. Freshwater areas are shallow and receive water from stream flow and floodout. Water is otherwise saline throughout and less than 6 m deep. The tidal range is 7 m. The site is a good example of a diverse, hydrologically related aggregation of marine, estuarine, and freshwater wetlands within the Central Queensland Coast bioregion [46]. The Landsat 2017 true-colour composite image exhibits the delineated polygonal outlines of the mangrove (Figure 6), saltpan/saltmarsh grass (Figure 7) and estuarine wetland (Figure 8) classes from the 2004 Landsat image that changed to the oceanic information class. Inundation occurred over a substantial area of three information classes: mangrove forest (87 hectares), saltpan/saltmarsh grass (49 hectares), and estuarine wetland (17 hectares).

**Figure 6.** Landsat 8 Operational Land Imager (OLI) true-colour image captured 27 April 2017 that highlights areas of mangroves that changed to the oceanic information class (shown in red) at Rocky Dam Creek/Cape Palmerston National Park.

**Figure 7.** Landsat 8 OLI true-colour image captured 27 April 2017 that highlights the areas of saltpan/saltmarsh grass that changed to the oceanic information class (shown in orange) at Rocky Dam Creek/Cape Palmerston National Park.

**Figure 8.** Landsat 8 OLI true-colour image captured 27 April 2017 that highlights areas of estuarine wetland that changed to the oceanic information class (shown in pink) at Rocky Dam Creek/Cape Palmerston National Park.

#### *3.3. Thematic Change Dynamics*

The thematic change summary matrix 2004–2017 shows the number of pixels in each of the nine land classes per zone (Table S3 in the Supplementary Materials) and the net percentage loss of each of the nine land cover classes per zone (Table S4 in the Supplementary Materials). The mangrove land class transitioned to three land classes: (1) open forest (net loss = 5.08%, 597 hectares), (2) estuarine wetland (net loss = 8.51%, 273 hectares), and (3) saltmarsh grass (net loss = 6.26%, 145 hectares). Three information classes transitioned to the cropping/grazing land class over the 14-year time period: the open forest (net loss = 3.3%, 75 hectares), the estuarine wetland (net loss = 4.95%, 552 hectares), and the saltmarsh grass, which deteriorated considerably (net loss = 4.26%, 1001 hectares). A total of 1628 hectares of coastal vegetation transformed into pasture. A proportion of the cropping/grazing land class changed to saltpan (net loss = 5.38%, 192 hectares). The open forest land class claimed a proportion of the estuarine wetland (net loss = 2.16%, 1122 hectares). The bare mudflat information class transitioned to three land classes: (1) saltpan (net loss = 14.44%, 591 hectares), (2) saltmarsh grass (net loss = 2.38%, 66 hectares), and (3) sand flat (net loss = 66.15%, 192 hectares).

#### *3.4. Time Series Analysis*

In a spatio–temporal analysis, we used the single explanatory variable of time to explore how the predictor variable, LULC, changed over the landscape 2004–2017. The map of the regression slope shows positive and negative values across the study site (Figure 9). The forested area (mangrove forest and open forest) was the dominant region that occupied the mid-way point in the data range, indicating that this area generally had little inter-annual variability and no decrease on average; this is the yellow area (average r value = 0.24) (Figure 9). A predominantly negative slope of the regression line indicates vegetation thinning and was pronounced in the land classes of cropping/grazing, estuarine wetland, and saltmarsh grass—these are represented by the dark green area (Pearson correlation coefficient r value range = −0.84–0.2) (Figure 10). The total vegetation decline in the cropping/grazing class was 1896 hectares. Strong positive slope values show a high exposure in the system through time but small inter-annual variability. High exposure areas include the saltmarsh grass adjacent to Rocky Dam Creek, saltpan, and bare mudflat land classes across the site extent—these are shown as the orange/red area (Pearson correlation coefficient r value range = 0.37–0.97) (Figure 10). The total change in the combined classes was 9375 hectares. Many areas throughout the study region displayed significant values (*p* value range = 0.001–0.099), demonstrating that land classes decreased in areal extent in the time series, e.g., the saltmarsh grass south of the saltpan zone, the estuarine wetland south of the saltmarsh grass zone, the bare mudflat in the stream inlets, scattered grazing sites, the open forest at Glendower Point (coastal mid-way point of the site) and the north-east boundary of the park, and the fringing mangroves along the coastline and stream channels.

**Figure 9.** Map of regression slope that highlights positive and negative values across the study site 2004–2017. High positive slope values show an increase in areal extent through time and are most pronounced in the saltpan and bare mudflat land classes across the site extent (shown in red); high negative slope values show a decrease in areal extent through time and are most pronounced in the land classes: cropping/grazing, estuarine wetland, and saltmarsh grass, as well as the fringing mangroves along the coastline and stream channels (shown in green) at Rocky Dam Creek/Cape Palmerston National Park.

**Figure 10.** Map of Pearson correlation coefficient r values across the study site 2004–2017. A strong positive correlation is highlighted in the land classes: saltpan and bare mud flat (shown in red); a strong negative correlation is highlighted in the land classes: cropping/grazing, estuarine wetland, and saltmarsh grass (shown in green). Significant values (*p* value range = 0.001–0.099) demonstrate that the following land classes decreased in areal extent in the time series: saltmarsh grass, estuarine wetland, bare mudflat in the stream inlets, scattered grazing sites, open forest at Glendower Point (coastal mid-way point of the site) and the north-east boundary of the park, and fringing mangroves along the coastline and stream channels at Rocky Dam Creek/Cape Palmerston National Park.
