<b>Trait-driven spectral signatures </b><b>reveal</b><b> allocation trade-offs within </b><b>a </b><b>clonal plant network</b>

Clonal integration reorganizes resource allocation among interconnected ramets. However, its reflection in the spectral signal remains poorly understood. We present a novel research concept that links the functional traits of ramets, the structural units that form a clonal plant network, with their spectral response, treating reflectance indices as indicators of resource redistribution within the network. Thirty fragments of the clonal networks of Maianthemum bifolium were analysed along a moisture gradient of coniferous forest habitats. Architectural traits were measured (leaf area, rhizome length, maximum distance between ramets, and number of knots), and based on hyperspectral measurements (350–2500 nm), 13 spectral indices related to pigment content, photochemical regulation, and water balance were calculated (i.e., VIS, NIR, SWIR, CRI, NDVI705, PRI, PSNDa, PSNDb, SIWSI, PPR, PVR, GNDVIhyper, and SR800_2170). Linear models revealed that variability in most spectral metrics was primarily determined by the internal architecture of the network and, to a lesser extent, by habitat type. Rhizome elongation was associated with increases in pigment indices (PSND and CRI) and leaf hydration-sensitive metrics (SWIR and SIWSI), indicating a carbon–water trade-off embedded in clonal expansion. In contrast, increased ramet density weakened photochemical signals (PRI and PVR), suggesting intensified local competition. The results indicate that spectral variability reflects the functional organization of modular organisms and may reveal internal allocation trade-offs, thereby linking leaf-level processes with the functioning of the entire clonal network.