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Shade alters grass growth and architecture by reducing root biomass

Citation

Solofondranohatra, Cedrique et al. (2021), Shade alters grass growth and architecture by reducing root biomass, Dryad, Dataset, https://doi.org/10.5061/dryad.2jm63xsm6

Abstract

Variable tree cover characterizes tropical grassy biomes. Light availability in the ground layer becomes increasingly limited as tree cover increases while open canopy environments are associated with a flammable grassy ground layer. Grass species dominating the ground layer of these ecosystems have adopted strategies to persist and proliferate with frequent fire. However, there is limited understanding of how grass growth and flammability traits respond to changes in light availability. We experimentally grew 14 grass species characteristic of the Malagasy Central Highlands for one year with four treatments of light exclusion ranging from 0 – 60%. Six plant functional traits and four leaf flammability traits were measured: plant height, bulk density, aboveground biomass, belowground biomass, ratio of root to shoot biomass, specific leaf area, leaf heat release capacity, temperature of maximum decomposition, total heat release and peak heat release rate. Belowground biomass, the ratio of root to shoot biomass and bulk density were substantially negatively affected by decreasing light availability while aboveground biomass showed no significant change although, there was a trend towards smaller plants at high shade. Specific leaf area increased with declining light availability. In terms of leaf flammability, unexpectedly, only leaf total heat release was significantly positively affected and the other traits were not. These suggest that any field alterations in grass flammability would be primarily underpinned by changes in plant architecture and potentially microclimate. The reductions observed in belowground biomass suggests that grasses would be rapidly lost from shaded environments with a diminished competitive capacity to resprout.

Funding

British Ecological Society, Award: EA16/1046, 2016