## Data and Methods  
### Study Area and Field Data Collection  
Banhado Grande (BG) (29\({}^{\circ}\)57\({}^{\prime}\) S-50\({}^{\circ}\)41\({}^{\prime}\) W, 5591 ha) in the east of the state of Rio Grande do Sul (RS) in the geomorphological region of the Inner Coastal Plain in a flat area with altimetry of up to 20 m (Figure 1) was used as a case study. BG forms the Gravatai River and acts as a natural flow regulator. It is a palustrine environment integrated with the Banhado Grande Environmental Protection Area (EPABG) for sustainable use, comprising marsh areas, flood plains, and rice fields that become connected in periods of large flooding pulses [34]. The lithology is predominantly sedimentary environments of heterogeneous active pests interconnected by floodplain deposits composed of silt-clay sand [35; 36]. The study area is located in a subtropical humid climate zone, with no defined rainy season [37]. The vegetation cover is dominated by macrophytes with heterogeneous distribution patterns, comprising the emerging species _Scirpus giganteus_, recently appointed as _Cyperus bysaceus Kunth_[38] with the most representative area and coverage in monodominance in the marsh, extending for \(\sim\)1507 ha [39], represented by the light blue polygon in Figure 1A, and occurs in areas with a presence of active peat dogs [40]. The species is caespitose perennial, 80-170 cm tall, widely distributed in the south of South America in freshwater and silted marshes and along the banks of creeks and small streams, with an emergent and amphibious biological form [38; 41; 42], (Figure 2A,B). The flooding regime in the area where _Cyperus bysaceus_ occurs is intermittent or only saturated soils [34]. The summarized methodological flow is described in the Graphical Abstract of the research, and further details are provided in this section. The field campaign was carried out throughout one annual cycle in 2018, at the end of the summer, winter, and spring (Table 1), periods characterized by low rainfall. The sampling survey was designed so that each plot corresponded to a transect similar to a 20 m \(\times\) 20 m Sentinel pixel. Nine plots were fixed with stakes, spaced at least 40 m apart (Figure 1B). The center position of the plots was recorded using global positioning system (GPS) equipment (Etrex Legend) with a margin of error of 3 m. The plots were positioned in an extensive area with a monospecific predominance of _Cyperus byssaceus_ so that the collection of reflectance data in the images would not occur outside the areas with the desired plants, due to possible positioning errors by the GPS and the sensors. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sensor** & **March/2018** & **August/2018** & **November/2018** \\ \hline Sentinel-2A & March 11 & August 28 & November 16 \\ PlanetScope & March 13 & August 17 & November 21 \\ Field data collection & March 14 & August 17 & November 22 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Image acquisition and field data collection dates. Figure 1: Location of the study area. (**A**) Sampling site, (**B**) simplified plot projection, (**C**) histogram with average values collected in each field campaign and general statistics. From each plot, three samples were collected at random, totaling 27 AGB samples according to the sampling guidelines [43; 44]. A 50 cm \(\times\) 50 cm square (0.25 m\({}^{2}\)) was used to collect the vegetation on the soil surface (Figure 2C). The samples were packed and dried in an oven at 60 \({}^{\circ}\)C until they reached a constant weight. The dried AGB was then measured on a precision scale to obtain the dry weight, expressed in grams. The Corg concentration was obtained using the Walkley-Black wet combustion method, which returns the organic carbon content (%) in 100 g of dry weight of AGB, converted to Corg stocks based on direct proportion [44; 45]. In general, the average AGB and Corg were 690 g/m\({}^{2}\) and 286 g/m\({}^{2}\), with the highest values observed in spring (Figure 1C), when new leaves are seen in greater quantity.