## 3 Results
### Spatiotemporal Dynamics of Macrophyte Communities
In particular, in T1 at 200 m, the \(\mathrm{D}_{\mathrm{RM}}\) class overtakes the BS class, in T2-T3-T4, this occurs at 300 m, while in T5 and T6 the dominant class is BS for the entire length of the transects (with the only exception of the second ROI of T5, i.e., 200 m, where the \(\mathrm{S}_{\mathrm{RM}}\) class is slightly more frequent). Lastly, comparing 2020 (lockdown) with previous years, the following results were obtained: in T1, 2020 is the only year in which the \(\mathrm{D}_{\mathrm{RM}}\) class is present both in spring and summer at 100 m; in T3, the improvement is found at 200 m with the presence of \(\mathrm{S}_{\mathrm{RM}}\) both in spring and summer; in the first 300 m of T4, 2020 is the most favorable year, especially for the \(\mathrm{D}_{\mathrm{RM}}\) class; while for the remaining transects (T2-T5-T6), no particular interannual differences were found. The possible effect of the lockdown period (March to May 2020) on macrophyte meadow growth was estimated by comparing spring images from each year. Comparison \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline \multirow{2}{*}{**Year–(Season)**} & \multicolumn{4}{c}{**Area (km\({}^{2}\))**} & \multicolumn{4}{c}{**Percentage (\%)**} \\ \cline{2-7}  & **BS** & \(\mathbf{S_{\mathrm{RM}}}\) & \(\mathbf{D_{\mathrm{RM}}}\) & **BS** & \(\mathbf{S_{\mathrm{RM}}}\) & \(\mathbf{D_{\mathrm{RM}}}\) \\ \hline
2015—Spring & NA & NA & NA & NA & NA & NA \\
2015—Summer & 1.335 & 0.919 & 1.717 & 33.62 & 23.14 & 43.24 \\
2015—Autumn & 2.263 & 0.994 & 0.714 & 56.99 & 25.03 & 17.98 \\ \hline
2016—Spring & 2.173 & 1.356 & 0.442 & 54.72 & 34.15 & 11.13 \\
2016—Summer & 2.056 & 1.446 & 0.469 & 51.78 & 36.41 & 11.81 \\
2016—Autumn & 2.783 & 0.921 & 0.267 & 70.08 & 23.19 & 6.72 \\ \hline
2017—Spring & 1.912 & 1.525 & 0.534 & 48.15 & 38.40 & 13.45 \\
2017—Summer & 1.128 & 0.962 & 1.881 & 28.41 & 24.23 & 47.37 \\
2017—Autumn & 1.633 & 1.483 & 0.855 & 41.12 & 37.35 & 21.53 \\ \hline
2018—Spring & 2.061 & 0.583 & 1.327 & 51.90 & 14.68 & 33.42 \\
2018—Summer & 1.390 & 0.664 & 1.917 & 35.00 & 16.72 & 48.27 \\
2018—Autumn & 2.545 & 1.039 & 0.387 & 64.09 & 26.16 & 9.75 \\ \hline
2019—Spring & 1.947 & 1.819 & 0.205 & 49.03 & 45.81 & 5.16 \\
2019—Summer & 1.653 & 2.196 & 0.122 & 41.63 & 55.30 & 3.07 \\
2019—Autumn & 2.035 & 1.935 & 0.001 & 52.25 & 48.73 & 0.03 \\ \hline
2020—Spring & 2.071 & 1.242 & 0.658 & 52.15 & 31.28 & 16.57 \\
2020—Summer & 1.221 & 1.808 & 0.942 & 30.75 & 45.53 & 23.72 \\
2020—Autumn & 2.483 & 0.616 & 0.872 & 62.53 & 15.51 & 21.96 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Area (km\({}^{2}\)) and percentage coverage of the three classes of bottom cover for each seasonal map (2015–2020): bare sediment (BS), sparse macrophytes (\(\mathrm{S}_{\mathrm{RM}}\)), and dense macrophytes (\(\mathrm{D}_{\mathrm{RM}}\)). of the early spring image of each year with the late spring image shows that from 2016 to 2019 there was always a decline in total macrophyte (RM) coverage: once for both subclasses (2016), sometimes only for D\({}_{\rm RM}\) (2017 and 2018), and finally only once for S\({}_{\rm RM}\) (2019). The only year characterized by a slight increase in both subclasses and, consequently, in total macrophytes was 2020 (Table 3). The interannual macrophyte cover trends are reported in Figure 4. Bare sediment bottom cover was greater than 50% in both 2005 and 2016, followed by 42% in 2019, while in the rest of the years investigated it was, on average, 37%. Macrophyte cover reached the highest values in 1997 and 2017 (72% for both), followed by coverage in the range from 65% to 69% in 2010, 2015, 2018, and 2020 (Figure 4). Higher variation was found in the density of the macrophytes in the years analyzed, with dense macrophytes cover being higher compared to sparse density in 1997, 2015, 2017, and 2018 (Figure 4).