Capturing functional trait response of dune plants using close-range remote sensing
Description
Coastal dunes are dynamic ecosystems characterized by steep environmental gradients that impose significant stress on plant communities. These stressors, such as salinity, drought, and nutrient-poor soils, create a mosaic of plant adaptations and functional trait diversity. Traditional ecological studies have focused on plant traits to understand species' responses to environmental conditions, but a gap remains in connecting plant functional traits to large-scale ecological processes through remote sensing. By focusing on the key species Cakile maritima and a broader dune plant community, we explored how vegetation indices correlate with specific physiological and morphological traits, including specific leaf area (SLA), leaf dry matter content (LDMC), and flavonoid concentration. This study presents a novel approach using close-range multispectral imaging to capture high-resolution (1.3 mm/px) data on plant functional traits in coastal dune ecosystems overcoming the limitations of broader-scale remote sensing methods which often suffer from lower spatial resolution and interference from non-vegetated areas. By manually selecting regions of interest (ROIs) for each species and filtering out background noise, we obtained precise multispectral signatures that accurately reflect the functional traits of individual plants and the entire community. Moreover, flavonoids explained a high percentage of the total variance of the multispectral indices. The study demonstrates the effectiveness of close-range multispectral imaging in linking plant traits to ecological processes, with significant implications for upscaling plant responses to environmental variable across larger spatial scales. Furthermore, the research outlines practical guidelines for collecting and processing close-range multispectral data, offering a valuable new tool for monitoring ecosystems.