R code to reproduce analyses of aboveground carbon stocks and associated plant diversity in fragmented and continuous forest sites in Sabah, Malaysian Borneo, 2017

The R code "carbon_stock_calculations.R" estimates aboveground carbon stocks for 49 plots in 14 fragmented forest sites and 4 continuous forest sites in Sabah, Malaysian Borneo, using the vegetation dataset ‘Vegetation and habitat data for fragmented and continuous forest sites in Sabah, Malaysian Borneo, 2017’. The 14 fragmented sites were all in Roundtable on Sustainable Palm Oil-certified oil palm plantations, and are hereafter termed 'conservation set-asides'. The code also estimates the aboveground carbon stocks of oil palm plantations for comparison. The R code "analyses_and_figures.R" runs analyses and makes figures of aboveground carbon stocks and associated plant diversity for these sites, as presented in Fleiss et al. (2020) This R code was created in order to investigate the following: (1) to establish the value of conservation set-asides for increasing oil palm plantation aboveground carbon stocks; (2) to establish whether set-asides with high aboveground carbon stocks can have co-benefits for plant diversity; (3) to compare the carbon stocks and vegetation structure of conservation set-asides with that of continuous forest, including assessing tree regeneration potential by examining variation in seedling density; (4) to examine potential drivers of variation in aboveground carbon stocks of conservation set-asides (topography, degree of fragmentation, and soil parameters); (5) to scale-up the estimates of the aboveground carbon stocks of conservation set-asides, in order to predict average carbon stocks of oil palm plantations with and without set-asides, and for varying coverage of set-asides across the plantation. Full details about this dataset can be found at https://doi.org/10.5285/9ff5cdca-b504-4994-8b07-5912ee6aff47R代码`carbon_stock_calculations.R`基于《马来西亚婆罗洲沙巴地区碎片化与连续森林样地植被及生境数据集（2017年）》（Vegetation and habitat data for fragmented and continuous forest sites in Sabah, Malaysian Borneo, 2017），对马来西亚婆罗洲沙巴地区14处碎片化森林样地与4处连续森林样地内共49个样方的地上碳储量进行估算。其中14处碎片化样地均位于可持续棕榈油圆桌会议（Roundtable on Sustainable Palm Oil）认证的油棕种植园内，下文将其统称为“保育预留区”。该代码同时估算油棕种植园的地上碳储量以用于对照比较。 R代码`analyses_and_figures.R`用于开展上述样地地上碳储量及相关植物多样性的分析与绘图，对应弗莱斯等人（Fleiss et al., 2020）的研究成果。 本套R代码的开发旨在开展以下5项研究：（1）明确保育预留区对提升油棕种植园地上碳储量的价值；（2）探究地上碳储量较高的预留区能否为植物多样性带来协同效益；（3）对比保育预留区与连续森林的碳储量及植被结构，包括通过分析幼苗密度变化评估树木更新潜力；（4）剖析保育预留区地上碳储量变化的潜在驱动因子（地形、碎片化程度与土壤参数）；（5）对保育预留区的地上碳储量估算结果进行尺度外推，以预测设置与未设置预留区的油棕种植园，以及不同预留区覆盖率下的平均碳储量。本数据集的完整细节可查阅https://doi.org/10.5285/9ff5cdca-b504-4994-8b07-5912ee6aff47