Evaluating the Woody Species Diversity by Means of Remotely Sensed Spectral and Texture Measures in the Urban Forests

Abstract

There is an urgent need to obtain an accurate data on biological diversity and its temporal variation, in order to adopt an appropriate protection strategy to manage the urban forest remnants on sustainable manner for future generations. RapidEye Satellite images with spatial resolution of 5 × 5 m (orthorectified pixel size), ASTER VNIR images with spatial resolution of 15 × 15 m and Landsat-8 OLI images with spatial resolution of 30 × 30 m were used to evaluate the woody species diversity in urban forest remnants. Pearson Correlation Coefficient (PCC) was used to determine the relationships between the woody species diversity at Alpha (α) level and the spectral & texture properties derived from the satellite images. PCC test showed a positive significant relationship between the brightness of the RapidEye satellite image (i.e., Atmospherically Resistant Vegetation Index; ARVI) and the Simpson’s Diversity Index (S) (r = 0.80, p < 0.01). In order to also estimate the beta (β) diversity in the study, the relationship between species rarefaction curves and spectral rarefaction curves was calculated through multiple regression analysis i.e., Landsat NDVI, ASTER NDVI and RapidEye NDVI (respectively, R2 = 0.99; 0.99; 0.98, p < 0.01). The findings of the study revealed that satellite image with a resolution of 5 m would be more appropriate to estimate the woody species diversity of urban forest remnants. However, medium resolution satellite images (Landsat) may be used to examine the species rarefaction curve and β diversity in forest remnants.