Linking drone and ground-based liana measurements in a congolese forest

Kacamak Asli Begum, Barbier Nicolas, Aubry-Kientz Mélaine, Forni Eric, Gourlet-Fleury Sylvie, Guibal Daniel, Loumeto Jean-Joël, Pollet Sasha, Rossi Vivien, Rowe Nick P., Van Hoef Yorick, Rejou-Mechain Maxime. 2022. Linking drone and ground-based liana measurements in a congolese forest. Frontiers in Forests and Global Change, 5:803194, 16 p.

Url - jeu de données - Entrepôt autre : https://figshare.com/collections/Linking_Drone_and_Ground-Based_Liana_Measurements_in_a_Congolese_Forest/5889176

Résumé : Lianas are abundant and diverse in tropical forests and impact forest dynamics. They occupy part of the canopy, forming a layer of leaves overtopping tree crowns. Yet, their interaction with trees has been mainly studied from the ground. With the emergence of drone-based sensing, very high-resolution data may be obtained on liana distribution above canopies. Here, we assessed the relationship between common liana ground measurements and drone-determined liana leaf coverage over tree crowns, tested if this relationship is mediated by liana functional composition, and compared the signature of liana patches and tree crowns in our drone images. Using drone platforms, we acquired very high resolution RGB and multispectral images and LiDAR data over two 9-ha permanent plots located in northern Republic of Congo and delineated liana leaf coverage and individual tree crowns from these data. During a concomitant ground survey, we focused on 275 trees infested or not by lianas, for which we measured all lianas ≥ 1 cm in diameter climbing on them (n = 615) and estimated their crown occupancy index (COI). We additionally measured or recorded the wood density and climbing mechanisms of most liana taxa. Contrary to recent findings, we found significant relationships between most ground-derived metrics and the top-of-view liana leaf coverage over tree crowns. Tree crown infestation by lianas was primarily explained by the load of liana climbing on them, and negatively impacted by tree height. Liana leaf coverage over individual tree crowns was best predicted by liana basal area and negatively mediated by liana wood density, with a higher leaf area to diameter ratio for light-wooded lianas. COI scores were concordant with drone assessments, but two thirds differed from those obtained from drone measurements. Finally, liana patches had a higher light reflectance and variance of spectral responses than tree crowns in all studied spectra. However, the large overlap between them challenges the autodetection of liana patches in canopies. Overall, we illustrate that the joint use of ground and drone-based data deepen our understanding of liana-infestation pathways and of their functional and spectral diversity. We expect drone data to soon transform the field of liana ecology.

Mots-clés Agrovoc : compétition végétale, plante ligneuse, forêt tropicale humide, arbre, partie aérienne, mesure (activité), télédétection, drone

Mots-clés géographiques Agrovoc : Congo

Mots-clés complémentaires : Liane, Canopée

Mots-clés libres : Central Africa, Woody vines, Canopy, Competition, UAV systems, Remote Sensing

Classification Agris : F40 - Écologie végétale

Champ stratégique Cirad : CTS 1 (2019-) - Biodiversité

Agences de financement européennes : European Commission

Programme de financement européen : H2020

Projets sur financement : (EU) Towards a new generation of plant-inspired growing artefacts

Auteurs et affiliations

• Kacamak Asli Begum, CIRAD-BIOS-UMR AMAP (FRA) - auteur correspondant
• Barbier Nicolas, IRD (FRA)
• Aubry-Kientz Mélaine, Université de Montpellier (FRA)
• Forni Eric, CIRAD-ES-UPR Forêts et sociétés (COG)
• Gourlet-Fleury Sylvie, CIRAD-ES-UPR Forêts et sociétés (FRA) ORCID: 0000-0002-1136-4307
• Guibal Daniel, CIRAD-PERSYST-UPR BioWooEB (FRA)
• Loumeto Jean-Joël, UMNG (COG)
• Pollet Sasha, GxABT (BEL)
• Rossi Vivien, CIRAD-ES-UPR Forêts et sociétés (COG) ORCID: 0000-0001-5458-1523
• Rowe Nick P., Université de Montpellier (FRA)
• Van Hoef Yorick, CIRAD-ES-UPR Forêts et sociétés (COG)
• Rejou-Mechain Maxime, IRD (FRA) - auteur correspondant

Source : Cirad-Agritrop (https://agritrop.cirad.fr/601543/)

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