Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Melbourne, Australia.
Grupo de Investigación de Biodiversidad, Medio Ambiente y Salud-BIOMAS, Universidad de las Américas (UDLA), Quito, Ecuador.
PLoS One. 2020 Mar 30;15(3):e0230612. doi: 10.1371/journal.pone.0230612. eCollection 2020.
Few studies exist that document how high-elevation Andean ecosystems recover naturally after the cessation of human activities and this can limit the implementation of cost-effective restoration actions. We assessed Andean forest (Polylepis stands) and páramo grassland recovery along an elevation gradient (3,600-4,350 m.a.s.l.) in the Yanacocha Reserve (Ecuador) where natural recovery has been allowed since 1995. Within the Yanacocha Reserve in 2012 and 2014 the aboveground biomass (AGB), aboveground necromass (AGN) and belowground biomass (BGB) carbon (C) stocks were measured and C sequestration rates calculated as proxy of ecosystem recovery. The soil organic carbon (SOC) stock to 36-cm depth was also quantified during the 2012 survey. To explore potential drivers of spatiotemporal variation of the forest and páramo C stocks they were related to abiotic and biotic variables. Andean forest C stocks were influenced mainly by disturbance history and tree-species composition. Páramo C stocks´ spatial variation were related to the elevation gradient; we found a positive significant trend in páramo AGB-C stocks with elevation, whereas we found a significant negative trend in AGN-C stocks. Likewise, significant temporal changes were found for AGB-C and AGN-C stocks. Net increases in AGB-C stocks were the largest in the Andean forest and páramo, 2.5 Mg C ha-1 year-1 and 1.5 Mg C ha-1 year-1 respectively. Carbon sequestration rates were partly explained by environmental variables. In the Andean forest, plots with low dominance of Baccharis padifolia were observed to present higher AGB-C and lower BGB-C sequestration rates. In the páramo, higher sequestration rates for AGB-C were found at higher elevations and associated with higher levels of growth-forms diversity. Temporal changes in BGB-C stocks on the contrary were non-significant. Our results indicated that terrestrial aboveground C sequestration rates might be an appropriate indicator for assessing Andean forest and páramo recovery after human disturbance.
几乎没有研究记录高海拔安第斯生态系统在人类活动停止后如何自然恢复，这可能限制了具有成本效益的恢复措施的实施。我们评估了 Yanacocha 保护区（厄瓜多尔）内海拔梯度（3600-4350 米）上的安第斯森林（Polylepis 林）和高山草原恢复情况，自 1995 年以来，这里已允许自然恢复。2012 年和 2014 年，在 Yanacocha 保护区内测量了地上生物量（AGB）、地上凋落物量（AGN）和地下生物量（BGB）碳（C）储量，并计算了碳封存率作为生态系统恢复的指标。2012 年调查期间还量化了 36 厘米深的土壤有机碳（SOC）储量。为了探讨森林和高山草原 C 储量时空变化的潜在驱动因素，我们将其与非生物和生物变量相关联。安第斯森林 C 储量主要受干扰历史和树种组成的影响。高山草原 C 储量的空间变化与海拔梯度有关；我们发现高山草原 AGB-C 储量与海拔呈正显著趋势，而 AGN-C 储量则呈负显著趋势。同样，AGB-C 和 AGN-C 储量也存在显著的时间变化。AGB-C 储量的净增加量在安第斯森林和高山草原最大，分别为 2.5 Mg C ha-1 year-1 和 1.5 Mg C ha-1 year-1。碳封存率部分由环境变量解释。在安第斯森林中，观察到 Baccharis padifolia 低优势的样地具有更高的 AGB-C 和更低的 BGB-C 封存率。在高山草原中，更高的 AGB-C 封存率出现在更高的海拔，并与生长形态多样性水平较高有关。相反，BGB-C 储量的时间变化不显著。我们的结果表明，陆地地上 C 封存率可能是评估人类干扰后安第斯森林和高山草原恢复的合适指标。
