Análisis de la dinámica temporal del NDVI en áreas protegidastres casos de estudio a distintas escalas espaciales, temporales y de gestión

Zusammenfassung

Data records of satellite images are a great tool to analyze changes in different aspects of vegetation functioning. Temporal analyses of these images are of great interest for the study and management of protected areas. In this work, we show three approaches that aim to evaluate changes in the mean, seasonality, and instability of the temporal dynamics (abrupt changes) of the photosynthetic capacity of vegetation in three study areas: the South American network of protected areas, the Spanish network of national parks, and two Andalusian natural parks. For each analysis, we used different data records of the Normalized Difference Vegetation Index (NDVI), a spectral index related to the fraction of photosynthetically active radiation intercepted by vegetation. The South American protected areas and the Spanish national parks showed significant trends in the NDVI dynamics that varied in magnitude and direction depending on their geopolitical and biogeographical situation. The Andalusian parks showed how different historical managements have led to a decrease in the stability of the NDVI temporal dynamics in particular ecosystems. As a whole, the three evaluations revealed how biodiversity conservation policies in protected areas cannot be based on static or mean situations since the functioning of protected ecosystems is changing in multiple aspects. Additionally, these approaches provide valuable information for the establishment of priorities in conservation, being capable of responding to questions such as, what biomes, countries or parks are experiencing the greatest changes?, or what management practices provide a greater stability to the ecosystem?