Integrated Fire Management as a Renewing Agent of Native Vegetation and Inhibitor of Invasive Plants in Vereda Habitats: Diagnosis by Remotely Piloted Aircraft Systems

Abstract

The Cerrado biome is being gradually reduced. Remote sensing has been widely used to investigate spatio-temporal changes in the landscape, which are frequently limited to mapping with orbital sensors, while the Remotely Piloted Aircraft System (RPAS) proved to be advantageous in terms of spatial resolution and the application of advanced digital processing techniques. In this study, we investigated a vereda (humid area) of a conservation unit in the state of Mato Grosso, Brazil. Object-Based Image Analysis (OBIA) was applied to images obtained by RPAS to distinguish the phytophysiognomies of plant strata from the vereda and to diagnose the recovery of native and invasive vegetation after prescribed burning. The study was carried out in the following five stages: biomass collection; quality analysis of the land cover; phytosociological survey; collection of control points using a GNSS receiver (type L1/L2); and the capture of aerial images with an RGB camera coupled to a DJI Phantom 4 Pro, which was performed through overflights in three different periods. Object–Based Image Analysis was subsequently performed using the Nearest Neighbor classifier combined with Feature Space Optimization, obtaining classifications with accuracy and Kappa indexes greater than 80% and 0.80, respectively. The results of image processing allowed us to infer that fire acted as a renewing agent for native vegetation and as an inhibiting agent for invasive vegetation. The classification analyses combined with the phytosociological analysis allowed us to infer that the vereda is in the process of maturation. Therefore, the study demonstrated the potential of data obtained by RPAS for the diagnosis and analysis of vegetation dynamics in small wetlands submitted to Integrated Fire Management (IFM).

Systematic review and best practices for drone remote sensing of invasive plants

“…In most cases, the flight ceiling remained below 125 m, and flights exceeding 200 m were rare (Samiappan, Turnage, Hathcock, Casagrande, et al., 2017; Wu et al., 2019), possibly because most focal species were smaller shrubs and grasses. About one‐fourth (23%) of studies reported flight speed, which ranged from 1 to 18 m/s (Nascente et al., 2022; Tian et al., 2022). Flight patterns were rarely reported (11%), but most followed a single grid/parallel lines (Perroy et al., 2017), double grid (Wijesingha et al., 2020) or zig‐zag (Gonçalves et al., 2022) formation.…”

“…Only 20% of studies reported the details of using GCPs for photogrammetric control although many more were inferred to have used these. GCP materials included plastic discs (Kedia et al., 2021), orange safety cones (Baron & Hill, 2020), black and white checkered boards (Wijesingha et al., 2020), compact discs (Lehmann et al., 2017), white panels (Samiappan, Turnage, Hathcock, & Moorhead, 2017) and even natural features (Nascente et al., 2022). However, very little justification for the number, type or location was provided, which aligns with other findings (Mesas‐Carrascosa et al., 2017).…”

“…Less than 20% of studies had an ecologically focused objective, such as estimating above‐ground biomass (Tian et al., 2022), determining environmental drivers of growth potential (Zhu et al., 2019) or tracking re‐emergence of species after disturbance (Nascente et al., 2022). Similarly, studies using drones to detect early emergence, project future spread and understand the drivers of invasion were rare.…”

“…In most cases, the flight ceiling remained below 125 m, and flights exceeding 200 m were rare (Samiappan, Turnage, Hathcock, Casagrande, et al, 2017;Wu et al, 2019), possibly because most focal species were smaller shrubs and grasses. About one-fourth (23%) of studies reported flight speed, which ranged from 1 to 18 m/s (Nascente et al, 2022;Tian et al, 2022).…”

Mapping Areas Invaded by Pinus sp. from Geographic Object-Based Image Analysis (GEOBIA) Applied on RPAS (Drone) Color Images

“…Nascente et al [59], on the other hand, also used a ready-to-fly multirotor quadricopter equipped with an RGB sensor. They mapped with GEOBIA the cover of invasive vegetation in vereda environments in the Cerrado biome.…”