海岛陆地生态系统固碳估算方法

陆地生态系统在调节全球碳平衡和减缓全球气候变化中起着重要作用。海岛作为一种特殊的生态系统,生物群落和环境与大陆基本相似。虽然海岛生态结构相对简单,物种的丰富程度比大陆低,但对全球碳循环也有一定的影响。在海岛陆地生态系统中,森林和灌草的种属相对较少,且不同纬度的海岛森林植被种属差异明显,可采用典型样地清查和生物量模型估算相结合的方法估算乔木层和灌草层的碳储量。采用模型估算固碳潜力时,根据海岛生态环境的特殊性,综合考虑岛陆面积、季节、风向、坡度、坡向、海拔、平均温度、降雨量、土壤理化性质等参数对其碳储量估算的影响。海岛植被生物多样性影响其土壤碳储存的生态服务功能,利用多元统计分析方法,建立岛陆植物物种丰度与土壤碳储量的空间回归模型,明确植物多样性的改变对岛陆土壤固碳能力的影响。此外,从土壤固碳的角度而言,海岛土壤-植物-微生物间相互作用是其重要的研究方向。利用现代分子生物学技术,研究海岛陆地生态系统的土壤-植物-微生物相互作用关系,有利于海岛土壤固碳潜力估算精度的提高。

Discussion of carbon sequestration estimates in the island terrestrial ecosystems

Terrestrial ecosystems play an important role in regulating the carbon balance and mitigating global climate change. Island is a special terrestrial ecosystem, on which the communities and environmental conditions are similar to that of the mainland, but its ecological structure is relatively simple, and the species richness is lower than that of the mainland. Island ecosystems still has strong ability of carbon storage, carbon fixation and plays an important role in the global carbon cycle. This work discusses carbon sequestration estimates in the island terrestrial ecosystems. Island regions are especially vulnerable to projected changes in eustatic sea level, storm impacts, and habitat suitability due to low-lying land and limited migration potential. The island area in the global is about 1/15 of the whole mainland, so the ecosystem of forest, shrub, and grass on islands has had an impact on the global carbon sequestration. Although the species of forest, shrub, and grass on islands is relative fewer, there is significant difference of biodiversity on the islands at different latitudes. The combining methodology of the estimate model of biomass and the inventory of sampling investigation can be selected to estimate the carbon storage of forests, shrub, and grass on islands. The estimate model of biomass is a specific type of modeling that seeks to mechanistically represent cycles of carbon at islands regional ecosystem through an integrated into account of biology and geochemistry. Using models to estimate carbon sequestration on the island, factors influencing the carbon storage assessment are considered to be identified. The factors covers the land area of the island, season, wind, slope, aspect, elevation, average temperature, rainfall, soil properties, and so on. Biodiversity also enhances the ability of ecosystems to maintain multiple functions, such as carbon storage, productivity, and the buildup of nutrient pools. If the maintenance of biodiversity is to be justified as a strategy for enhancing ecosystem services, it is essential to understand how biodiversity affects ecosystem multifunctionality. Nevertheless, the relationship between biodiversity and ecosystem multifunctionality, especially carbon storage, has seldom been studied in islands. It is focused on how the richness of perennial vascular plants (hereafter "species richness") and a range of key abiotic factors (climate, slope, elevation, and soil texture) influence carbon storage in different typical islands ecosystems. The direct relationship between species richness and carbon storage on island can be evaluated using both ordinary least-squares (OLS) and spatial regression models. And these results will suggest that the correlation between species richness and carbon cycle may be a general pattern in nature that reflects a cause-and-effect linkage. Furthermore, a large proportion of photosynthetical fixed carbon is directed belowground to roots and associated microorganisms, potentially affecting carbon sequestration either positively or negatively. A better mechanistic understanding of how the belowground allocation of carbon affects long-term sequestration rates is crucial for predictions of how the currently large carbon stock in island soils may respond to altered climate change, elevated CO₂ levels, and other environmental shifts. Fungi play important roles in island soil ecosystems, as the decomposers of organic matter and the root-associated mediators of belowground carbon transport and respiration. It will be profiled the relative abundance of major functional groups of fungi through the depth profile of island soil by use of modern gene technology. And the results will elucidate the mechanisms underpinning carbon sequestration in island soil and highlight the importance of root-associated fungi for ecosystem carbon balance.