Termite Mound Identification through Aerial Photographic Interpretation in Lubumbashi, Democratic Republic of the Congo: Methodology Evaluation

Abstract

Abstract:Tropical termites are of critical importance for ecosystem functioning and ecosystem services in woodland and savannah areas. Termite mounds can also be used as fertilizer and biological indicators of anthropogenic disturbance linked to agriculture or charcoal production. Remote sensing may help to identify and characterize termite mound density and distribution at low cost. To test its effectiveness, termite mounds were identified in the field and compared with the results of image interpretation of free Google Earth aerial photographs. This comparison was carried out for 17 sites in the hinterland of the mining city of Lubumbashi, Katanga, Democratic Republic of the Congo, which faces high population growth, food insecurity, and intense fragmentation and degradation of the original Miombo woodland cover. The influences of mound height and diameter as well as the timing of the image capture (year and dry or wet season) were statistically tested. The actual number of termite mounds observed in the field was generally overestimated on the corresponding image. Height and wet season favoured correct identification, while spatial distribution was not significantly influenced by misidentifications. A corrective model was defined and its relevance statistically verified. Mound identification using Google Earth appears efficient so long as the precise individual mound position is not concerned. This approach represents considerable cost reduction for field surveys of termite mounds.Keywords: anthropogenic biological indicator, food self-sufficiency, Macrotermes, aerial photographic interpretation, woodland Résumé Les termites des régions tropicales sont d'une importance critique pour le fonctionnement et les services écosystémiques dans les régions de forêt claire et de savane. Les termitières peuvent également être utilisées comme engrais et bio-indicateurs de perturbations anthropiques telles que l'agriculture ou la production de charbon. La télédétection peut contribuer à identifier et caractériser la densité et la distribution des termitières à moindres frais. Afin de tester son efficacité, les termitières ont été identifiées sur le terrain et comparées avec les résultats d'interprétation de photographies aériennes Google Earth en libre accès. Cette comparaison a été appliquée sur 17 sites dans l'hinterland de la ville minière de Lubumbashi, Katanga, République Démocratique du Congo, confrontée à une croissance élevée de population, à l'insécurité alimentaire ainsi que d'intenses fragmentation et dégradation de la couverture originelle de forêt claire (Miombo). Les influences de la hauteur et du diamètre des termitières ainsi que de la période d'acquisition de l'image (année et saison) ont été testées statistiquement. Le nombre de termitières observées sur le terrain est généralement surestimé sur l'image. La hauteur et la saison des pluies en favorisent l'identification correcte, tandis que la distribution spatiale n'est pas significativement influencée par les erreurs d'identification. Un modèle correcti...

Marmots from space: assessing population size and habitat use of a burrowing mammal using publicly available satellite images

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