Ecosystem stability is though to be dependent upon biodiversity such that communities with greater diversity will be less prone to large fluctuations in ecosystem function. In forested ecosystems, carbon storage is one function of particular interest for its potential role in mitigating anthropogenic climate change. We examined relationships between diversity and carbon storage dynamics in a subtropical broadleaved forest in Taiwan. All woody stems in a 25 ha plot (divided into 625 quadrats) were tagged and measured (diameter at breast height) in 2004, 2009, and 2014. We calculated the coefficient of variation in aboveground biomass (CV AGB) and the change in coarse woody productivity (delta CWP) to serve as measures of ecosystem stability. Linear regression was used to test for relationships between these stability metrics and species richness, Shannon diversity, functional richness, and function dispersion.
Results/Conclusions
Overall, taxonomic and functional diversity were weakly related to temporal stability of woody aboveground biomass in Fushan. Quadrats with higher mean species richness over the ten-year period tended to have lower variability in aboveground biomass (greater stability) through time (R2 =0.005, P = 0.0488). Quadrats with higher mean Shannon diversity also tended to have lower variability in AGB (R2 =0.015, P = 0.0011). Functional richness was not a significant predictor of AGB variability (P = 0.18). Interestingly, AGB variability was negatively related to 2009 functional dispersion (R2 =0.03, P < 0.0001), but positively related to 2014 functional dispersion (R2 =0.02, P < 0.0001). Our other stability metric, delta CWP, did not show any significant relationships with mean richness, mean Shannon diversity, functional richness, or functional dispersion. Visual inspection of these data via scatterplot revealed a wide range of temporal variability in AGB and CWP at low levels of taxonomic and functional diversity, whereas high diversity quadrats tended to be more stable. This pattern is consistent with the diversity-stability hypothesis, but further analyses are needed to understand how other factors, such as topography, soil properties, and typhoon disturbance, are interacting with diversity-stability relationships and dynamics at this site.