• Biomass of an alpine meadow was estimated by hyperspectral data • Effects of landscape-level functional composition on biomass was scale dependent • Landscape-level means of functional traits determined biomass at finer scales • Functional richness of leaf thickness promoted biomass at coarser sampling resolution Vegetation biomass production is determined by community composition under the mediation of environments. However, the spatial scale dependence of the effect of functional trait characteristics, as well as of environmental regulation in complex landscapes composed of various patches, remains unclear. In this study, we retrieved several functional traits, including specific leaf area (SLA), leaf thickness (LT), and chlorophyll a content (CAC), based on satellite hyperspectral images in an alpine meadow landscape on the Qinghai-Tibet Plateau at a resolution of 10 m. By calculating means and diversity of these traits at various sampling radii (25 m, 50 m, 100 m and 200 m), we examined the hypothesis about the scale-independent effects of dominant patches and the scale-dependent effects of patch-based functional diversity on aboveground biomass at the landscape level. The results revealed that the positive effects of mean SLA and LT and the negative effects of mean CAC on biomass remained consistent across different scales (as measured by different sampling resolutions). In comparison, the positive effect of functional richness (FRic) for LT on biomass emerged only at a coarse sampling resolution of 200 m radius. With expanding sampling resolutions, the impacts of temperature and solar radiation on functional trait composition became stronger, but soil thickness had consistent influences on mean trait values and biomass. Our findings partially confirmed the hypothesis, demonstrating the scale-independent effect of the mean functional traits of dominant community patches and the scale-dependent effect of patch complementarity for specific traits on meadow biomass. This study underscores the diverse impacts of functional trait composition in maintaining biomass in alpine meadows and stresses the necessity of considering spatial scales in studying and managing ecosystem functions.
Zhang et al. (Sun,) studied this question.