Assessments of biodiversity, carbon, and their relationships in Nepalese forest commons: Implications for global climate initiatives

Abstract

Assessments of forest carbon, biodiversity, and their relationships have become important, particularly to devise effective approaches to forest policy and management, particularly in the context of emerging carbon-forestry. We measured forest data and estimated biodiversity and carbon from 620 plots across Nepal and found an average of 3.67 ± 0.09 effective numbers of plant tree species (eH') per plot (250m2) and 98.30 ± 4.19 Mg ha-1 Above Ground Tree and Sapling Carbon (AGBC). Our results indicated highly variable biodiversity and carbon across plots, indicating the potential for additional biodiversity and carbon storage. For instance, the plots in the upper quartile of eH' had 5 times greater mean eH' (6.89 ± 0.30) compared to the plots in the lowest quartile (1.21 ± 0.08). Similarly, the plots in the top quartile of the AGBC had 18 times higher mean AGBC (244.19 ± 16.45 Mg ha-1) compared to the plots in the lowest quartile (11.09 ± 1.25 Mg ha-1). We found > 80% carbon occurs in 10 dominant species. Our results reflect the complex and varied relationships of carbon and biodiversity across different forest categories. We found weak positive correlations between biodiversity and carbon storage (P < 0.27) and small significant coefficients of biodiversity indices with AGBC, indicating the absence of tradeoffor weak possibility for synergy between carbon-forestry and biodiversity conservation. Our results reinforce the need of biodiversity safeguards in carbon-forestry.