PLANT SPECIES MONITORING IN THE CANARY ISLANDS USING WORLDVIEW-2 IMAGERY

Abstract. The physical and climatic features of a relatively small volcanic island such as Tenerife (Canary Islands, Spain) cause increased difficulties to vegetation monitoring by means of moderate resolution satellite data. The use of multispectral very high resolution WorldView-2 (WV2) imagery provides promising perspectives for vegetation mapping in such a heterogeneous landscape. In order to assess its potential to estimate the cover fraction of dominant plant species in endemic Macaronesian laurel forests and heathlands, a hierarchical Multiple Endmember Spectral Mixture Analysis (MESMA) was performed within a study area where different patches from mature forest, to degraded forest and pine plantations can be found. First, a selection of pure pixels in the WV2 image for fern, Morella faya Ait., Laurus novocanariensis and the introduced species Pinus radiata were used to build a spectral library for each species. Last species Erica arborea L. was characterized in field by means of an ASD FieldSpec spectroradiometer, due to the rarity of pure pixels in this case, and to the simultaneous presence of two spectral subclasses depending on its flowering onset; WV2-adjusted spectral signatures from field reflectances were estimated by empirical calibration. Preliminary results showed a good separation of degraded from mature native forests and from plantations, although pine cover fraction is, in general, underestimated. The second MESMA cycle was useful to tell between most similar species, like in case of M. faya and L. novocanariensis.