Analysis of the NDVI temporal dynamics in protected areas: three study cases at different spatial, temporal, and management scales

Abstract

Alcaraz-Segura, D., Baldi, G., Durante, P., Garbulsky, M.F. (2008). Analysis of the NDVI temporal dynamics in protected areas: three study cases at different spatial, temporal, and management scales. Ecosistemas 17(3):108-117.

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?