喀斯特地区碳储量对土地利用模式的响应——以南北盘江流域为例

喀斯特地区生态系统脆弱,对气候变化响应敏感,空间异质性强,碳汇潜力大。喀斯特生态治理对土地利用格局的改变,会导致生态系统碳储量的显著变化,对陆地生态系统碳循环和区域生态安全具有深远影响。以喀斯特典型区南北盘江流域为例,运用InVEST模型和热点分析评估流域2000—2020年土地利用变化对碳储量时空分布的影响,根据碳储量集聚特征使用FLUS-Markov模型分区预测生态系统碳储量对不同土地利用模式的响应。结果表明：(1)2000—2020年,研究区土地利用类型由高碳密度的地类转为较低碳密度的地类,致使生态系统碳储量呈减少趋势,累计损失90.36×10⁵t C。(2)2000—2020年碳储量在空间上呈现“西低东高”的格局。热点区集中分布在东部和东南部,冷点区主要分布在西部和西南部,弱显著区大多在北部。(3)各热点分区在不同模式下固碳能力差异显著。热点区在不同模式下的平均碳密度均大于155.40t/hm²,显著高于2020年南北盘江流域的平均碳密度143.59t/hm²,整体固碳功能突出;弱显著区的碳汇能力与研究区平均水平...

Responses of carbon storage to land use pattern in karst area: A case study of Nanbei Panjiang River Basin

As we all know, karst areas have fragile ecosystems with strongly spatial heterogeneity and large carbon sink potential, which is sensitive to climate change. The change of land use pattern caused by karst ecological governance will lead to significant changes in ecosystem carbon storage, which has far-reaching impacts on the carbon cycle of the terrestrial ecosystem and regional ecological security. Take the Nanbei Panjiang River Basin in the typical karst area as an example, the InVEST model and hotspot analysis were used to assess the impacts of land use change on the spatial and temporal distribution of carbon stocks in the Nanbei Panjiang River Basin from 2000 to 2020. At the same time, the FLUS-Markov model was used to predict the changes of ecosystem carbon storages under different land use patterns, according to the characteristics of carbon storage agglomeration. Research results showed that: (1) from 2000 to 2020, the land use type in the study area has changed from high carbon density to low carbon density, resulting in a cumulative loss of 90.36×10⁵ t in ecosystem carbon storage. (2) Carbon storage presented a spatial pattern of "low in west and high in east" area. Hot spots were concentrated in the east and southeast study area, while cold spots were mainly distributed in the west and southwest and weak significant areas were mostly in the north area. (3) Under different patterns, the carbon fixation capacities of each hot spots were significantly different. The average carbon density of hot spots was more than 155.40 t/hm², which was obviously higher than the average carbon density of Nanbei Panjiang River Basin (143.59 t/hm²) in 2020. At the same time, the carbon sink capacity of the weakly significant area was close to the average level of the study area, and the carbon storage loss was less under Natural Development Pattern (NDP) and Economic Development Pattern (ECP). On the one hand, the carbon storage loss was severe in cold spot area under NDP and ECP, on the other hand the carbon sink increase rate was 1.38×10⁵ t/a under Ecological Protection Pattern (EPP), which was significantly higher than the weakly significant area (0.30×10⁵ t/a). In general, it means that the carbon fixation capacity of land use pattern under the influence of EPP is better than that of NDP and ECP. This study can provide some scientific basis for the optimization of land use pattern and ecosystem management in karst areas.