Biodiversity facets affect community surface temperature via 3D canopy structure in grassland communities

Abstract

Canopy structure is an important driver of the energy budget of grassland ecosystem and is, at the same time, altered by plant diversity. Diverse plant communities typically have taller and more densely packed canopies than less diverse communities. With this, they absorb more radiation, have a higher transpiring leaf surface and are better coupled to the atmosphere which leads to cooler canopy surfaces. However, whether plant diversity generally translates into a cooling potential remains unclear and lacks empirical evidence. Here, we assessed how functional identity, functional diversity and species richness of grassland communities in the Jena Experiment predict the mean and variation of plant surface temperature mediated via effects of canopy structure. Using terrestrial laser scanning, we estimated canopy structure describing metrics of vertical structure (mean height, LAI), the distribution (evenness) and the highest allocation (centre of gravity) of biomass along height strata. As metrics of horizontal structure, we considered community stand gaps, canopy surface variation and emergent flowers. We measured surface temperature with a thermal camera. We used SEM models to predict biodiversity effects on the surface temperature during two seasonal peaks of biomass. Before the first cut in May, herb‐dominated communities directly promoted lower leaf surface temperatures. However, communities with lower centre of gravity (mostly herb dominated) also increased canopy surface temperatures compared with grass‐dominated communities with higher biomass stored in the top canopy. Grass‐dominated communities showed a smaller variation of surface temperatures, which was also positively affected by species richness via an increase in mean height. In August, mean surface temperature decreased with increasing community CC and LAI. The variation of surface temperature was greater in herb‐dominated than in grass‐dominated communities and increased with plant species richness (direct effects). Synthesis. The mean and variation of canopy surface temperature were driven by differences in functional group composition (herbs‐ vs. grass dominance) and to a lesser extent by plant diversity. These effects were partly mediated the metrics of canopy structure but also by direct effects unrelated to the structural metrics considered.

Plant diversity stabilizes soil temperature

“…As a result, SOC acts as an insulator, and the presence of SOC cools the soil in summer and has a warming effect in winter 36 . Similarly, aboveground plant leaf cover can also act as an insulator to stabilize soil temperature 23 . Initial mixed-effects models modelling the effects of covariate data on annual soil temperature stability were performed in R (Extended Data Fig.…”

Research Progress of Grassland Ecosystem Structure and Stability and Inspiration for Improving Its Service Capacity in the Karst Desertification Control

“…By monitoring light cut-offs in the canopy of grassland communities with high species diversity, researchers found a positive correlation between plant species richness and multiple ecosystem functions, at which time grassland resource utilization was high. The relationship between grassland biodiversity-productivity and management intensity was also positively correlated when supplemented by sound grassland management [ 124 ]. Thus, a rational vertical canopy structure and a scientific horizontal structure not only maintain the biodiversity of the grassland, but also ensure its productivity, thus providing the basis for multi-functional grassland management [ 125 ].…”

Assessing the Impact of Soil on Species Diversity Estimation Based on UAV Imaging Spectroscopy in a Natural Alpine Steppe

“…Although there are still uncertainties for obtaining grassland canopy structures, several structural characteristics of grassland have been estimated by terrestrial laser scanning. For instance, Guimarães-Steinicke et al [81] regarded mean height and LAI as metrics of vertical structure, community stand gaps, canopy surface variation and emergent flowers as metrics of horizontal structure. Airborne or UAV-based LiDAR data could also be attempted to estimate the canopy structure characteristics of grassland over large areas [82].…”