The aboveground biomass of vegetation is significant to the global carbon cycle and climate change mitigation. Both biotic and abiotic factors can impact this biomass, either directly or indirectly, with these effects varying according to the spatial scale of the data collected.
In a study published in Forest Ecology and Management, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) and their collaborators sought to examine how biotic factors (including forest structure attributes, community-weighted mean of traits, and functional diversity) and abiotic factors (such as topography and soil properties) affect the aboveground biomass at two spatial scales (i.e., 20 m × 20 m and 50 m × 50 m) in a tropical seasonal rainforest in southwestern China.
They found that, at both spatial scales, the relative importance of biotic factors on above-ground biomass was greater than that of abiotic factors.Forest structure was the most important determinant of variation in aboveground biomass, which emphasized the importance of forest structure in the context of forest management and restoration to improve forest carbon sequestration and mitigate climate change.
The mass ratio effect played an important role in determining aboveground biomass at the small spatial scale, while there was no evidence to support the niche complementarity effect at either scale. The community-weighted mean of traits indirectly influenced aboveground biomass via forest structure.
They further found higher aboveground biomass when species had conservative resource-use strategies. At the large scale, functional richness and functional evenness indirectly reduced aboveground biomass by negatively influencing forest structure.
In addition to their indirect effects mediated by forest structure and/or traits, topography and soil properties had direct effects on aboveground biomass. Contribution of topography to aboveground biomass increased with spatial scale. Convexity negatively influenced aboveground biomass via its effects on soil properties and forest structure.
Concerning forest management, the researchers suggested that it is important to consider the scale dependence of the effects of abiotic and biotic factors on aboveground biomass. At larger scales, afforestation and forest restoration should be carried out in suitable terrains to maximize carbon storage. At smaller scales, forest management should prioritize regulating biotic factors.
" Our findings underscore the importance of focusing on the scale-dependency of forest structure and aboveground biomass drivers in the context forest management and restoration to enhance forest Carbon sequestration and mitigate climate change,”said LIN Luxiang of XTBG.
Published: 12 December 2024
