Seasonal variations in the riparian vegetation of the sub-basin “La Mula”, North of Costa Rica

Abstract

Introduction. Agricultural activities and atmospheric anomalies represent a high percentage of alterations in riparian ecosystems, rapidly modifying ecosystem services, such as the loss of environmental quality. This research measured the effect of climatic variations on the use of agricultural land use associated with the riparian zone. Methods: With the use of Lansat 8 images and their preprocessing in SAGA GIS, data extraction from the Normalized Vegetation Difference Index (NDVI) per month was performed in 2022. Statistical analyses were done in RStudio for Kruskal Wallis (KW) test. Within the method, the types of correlations between atmospheric data and NDVI were analyzed. Results. The dispersion of the data in land uses and adjacent vegetation (Va) presented similar values throughout the year, considering that the latter (Va) showed values associated with average vegetation. Data from the KW test indicated a p = 0.0016 refuting the existence of differences between land uses and Va. A Post hoc test indicated statistically differences were only Vegetation adjacent to Livestock (Va-G) / Cane (C), Va-G / Watermelon (S) and Livestock (G) / C. On the other hand, NDVI in G was inversely proportional to temperature (rho = -0.62, value of the negative correlation between land use and temperature). Conclusion: In many cases, the Va to land uses such as Grasslands (P), S and C did not present significant differences. A comparative analysis between the dataset indicated that G and Va-G were soils with better vegetation status in the La Mula sub-basin.