Pastured land survey: Spring 2020

The southern section of the Northern survey area is currently unfenced cattle grazing lands. Potential to fence this area in the future and consider revegetation, makes this region an additional area of interest. The pastured area is approximately 12 ha of land adjacent to the mangroves and marine environment (Figure 1)). The pasture is grazed by beef cattle, owned privately. As the pasture is going to vary seasonally and due to grazing pressure attempting to assess pasture biomass or growth rates will not be an easy measure for vegetation change assessment. To assess the change in vegetation in the presence of grazing focus was given to pasture species composition and a combination of remote sensing and satellite image analysis (either using the WorldView3 image, or freely available sentinel satellite imagery). The long-term productivity change using sentinel satellite NDVI (Figure 1) will be used to provide a broad overview of changes on the site over time. These initial changes will be reported in the Autumn 2021 report and only the baseline is presented here. Satellite imagery was verified through ground-truth sampling. The area was divided into 3 zones to stratify sample 12 permanent pasture comb sites (4 reps in each zone) using a fixed site recording of basal species composition. The pasture comb is a 1 m x 1 m quadrat divided in 10 cm grids giving 100 pasture composition points. Dry Weight Rank Method (Mannetje and Haydock 1963) was applied on a regular grid transect (modified Botanal technique) taking 100 quadrats of ranked pasture dry weight.