Habitat Mapping and Quality Assessment of NATURA 2000 Heathland Using Airborne Imaging Spectroscopy

Abstract

Appropriate management of (semi-)natural areas requires detailed knowledge of the ecosystems present and their status. Remote sensing can provide a systematic, synoptic view at regular time intervals, and is therefore often suggested as a powerful tool to assist with the mapping and monitoring of protected habitats and vegetation. In this study, we present a multi-step mapping framework that enables detailed NATURA 2000 (N2000) heathland habitat patch mapping and the assessment of their conservation status at patch level. The method comprises three consecutive steps: (1) a hierarchical land/vegetation type (LVT) classification using airborne AHS imaging spectroscopy and field reference data; (2) a spatial re-classification to convert the LVT map to a patch map based on life forms; and (3) identification of the N2000 habitat type and conservation status parameters for each of the patches. Based on a multivariate analysis of 1325 vegetation reference plots acquired in [2006][2007]24 LVT classes were identified that were considered relevant for the assessment of heathland conservation status. These labelled data were then used as ground reference for the supervised classification of the AHS image data to an LVT classification map, using Linear Discriminant Analysis in combination with Sequential-Floating-Forward-Search feature selection. Overall classification accuracies for the LVT mapping varied from 83% to 92% (Kappa ≈ 0.82-0.91), depending on the level of detail in the hierarchical classification. After converting the LVT map to a N2000 habitat type patch map, an overall accuracy of 89% was obtained. By combining the N2000 habitat type patch map with the LVT map, two important conservation status parameters were directly deduced per patch: tree and shrub cover, and grass cover, showing a strong similarity to an independent dataset with estimates made in the field in 2009. The results of this study indicate the potential of imaging spectroscopy for detailed heathland habitat characterization of N2000 sites in a way that matches the current field-based workflows of the user.

Multiple Flights or Single Flight Instrument Fusion of Hyperspectral and ALS Data? A Comparison of their Performance for Vegetation Mapping

“…The results of single sensor classifications (ALS15, HS15, ALS17, and HS17) confirm the high data relevance, generating high Kappa values ranging from 0.70 to 0.79 (Table 6). These results conform with findings of other researchers who successfully classified Natura 2000 habitats using only ALS [8,41,42] or only HS data [43,44] with similar accuracies. This allows us to claim that for the purposes of non-forest Natura 2000 habitats classification, for which the data sets are correctly matched in terms of spatial resolution (2 m 2 ) and point cloud density (8 pts./m 2 ), both sensors can be useful.…”

Object-Based Land Cover Classification of Cork Oak Woodlands using UAV Imagery and Orfeo ToolBox

“…The use of unmanned aerial vehicles (UAVs) or UA systems (UASs) in forest and environmental monitoring [3][4][5][6][7][8][9][10][11][12][13][14][15] is currently in an expansion phase, encouraged by the constant development of new models and sensors [3,16,17]. Detailed reviews focusing on the use of UAVs in agro-forestry monitoring, inventorying, and mapping are provided by Tang and Shao [16], Pádua et al [3], and Torresan et al [18].…”

Classification of Expansive Grassland Species in Different Growth Stages Based on Hyperspectral and LiDAR Data

“…Scientists analysed C. epigejos and M. caerule spreading using statistical methods [44,45]. Several authors used hyperspectral images to identify particular species encroaching into heathlands: M. caerulea entering the Natura 2000 habitat classification was addressed by Mücher et al [46] in the areas of Ederheide and Ginkelse heide in the Netherlands and by Haest et al [47] in Kalmthouse Heide in Belgium. C. epigejos was mentioned by Schmidt et al [48] in Oranienbaum Heath located near Dessau in the Elbe-Mulde-lowland in Saxony-Anhalt in Germany, but only with encroaching into heathlands being the main object of the study.…”