Grassland biomes are one of the largest terrestrial ecosystems on the planet, providing critical ecological, social, and economic benefits. However, they are subjected to natural and anthropogenic stresses such as precipitation, temperature variability, and widespread land degradation. Invasive plant species, for example, pose enormous challenges regarding biodiversity loss and degradation. Therefore, we need to keep up with and improve our knowledge of how they change, especially over space and time, to make good decisions about their productivity, management, and conservation.
However, questions remain in (i) mapping and invasion science regarding a methodological framework for mapping invasive plant species (Opuntia stricta) using satellite remote sensing, (ii) understanding the spatiotemporal relationship between grassland greenness, communities, precipitation, temperature, and grazing factors, and (iii) our understanding of the spatial variation in grassland community types and their palatability probability. As a result, this study aimed to better understand the spatiotemporal dynamics in Kenya’s heterogeneous semi-arid grasslands by characterising the grassland into grassland communities and palatable and non-palatable plants. Additionally, it evaluates the intra-seasonal drivers of grassland changes at a site-specific level in 2019.
The results show that combining Sentinel-2 spectral data, vegetation, and topographic indices is sufficient to map Opuntia stricta in a complex, heterogeneous semi-arid landscape. Additionally, precipitation, temperature and grazing, though at different times, are the major drivers of intra-seasonal grassland dynamics in semi-arid areas. Furthermore, the study found Sentinel-2 imagery to be adequate in achieving fine-scale spatial variations in grassland communities and inferring palatability probability in heterogeneous semi-arid grasslands. Finally, these findings and recommendations can help us better understand grassland dynamics and uncertainty modelling, as well as improve our understanding of plant-animal interactions, which can lead to management implications for rangeland management in terms of productivity, conservation, and rehabilitation
