Abstract:

There are abundant vegetation types in Guangdong Province and studying the response of vegetation net primary productivity (NPP) in different ecosystems to climatic factors is important for improving the quality of the ecological environment. Based on land cover type, vegetation NPP, and meteorological observation data, the spatiotemporal characteristics of vegetation NPP in different ecosystems in Guangdong Province and their responses to climate factors were analyzed. The results showed that the average temperature and precipitation in Guangdong Province exhibited a slight upward trend from 2000 to 2020, with area proportions of positive growth accounting for 86.8% and 64.8%, respectively. Sunshine hours showed a downward trend, with the area proportion of negative growth accounting for 82.4%. Vegetation NPP showed a fluctuating upward trend, with an average annual value of 1011 g∙m⁻² and an annual growth value of 6.7 g∙m⁻²∙a⁻¹. The positive growth zone accounted for 91.9% of the provincial area. The average annual NPP of the forest ecosystem and the proportion of positive growth areas were highest at 1107 g∙m⁻² and 95.6%, respectively. The average annual NPP of wetland ecosystems and the proportion of positive growth areas were the lowest, at 686 g∙m⁻² and 89.5%, respectively. Vegetation NPP showed significant positive correlations with temperature, precipitation, and sunshine hours, with correlation coefficients of 0.81, 0.48, and 0.68, respectively. The correlation coefficients all passed the significance test at p=0.001, which showed that temperature had the most significant impact on vegetation NPP, followed by sunshine hours and precipitation. Temperature and sunshine hours had the greatest impact on forest ecosystem NPP, and the smallest impact on wetland ecosystems. Precipitation has the greatest impact on farmland ecosystems and the smallest impact on wetland ecosystems. Regarding response time, the correlation coefficients between NPP and temperature, as well as NPP and sunshine hours, reached their maximum values in the current month, whereas the correlation coefficient between NPP and precipitation reached its maximum in the following month. This means that there were no lags in NPP response to temperature and sunshine hours. Regarding the duration of the impact, the correlation coefficient between temperature and NPP was relatively high from the current month to the following two months, that between sunshine hours and NPP was relatively high in the current month, and that between precipitation and NPP was relatively high from the current month to the following three months. Therefore, the impact of precipitation on NPP was the greatest.

Key words: net primary productivity, climate factors, ecosystem, spatiotemporal variations, response

摘要：

广东省具有丰富的植被类型，研究不同生态系统植被净初级生产力（NPP）对气候因子的响应，对提升全省生态环境质量具有重要意义。基于植被净初级生产力、地面观测数据和土地利用分类等数据，制作广东省生态系统分类数据，分析广东省不同生态系统植被NPP的时空特征及其对气候因子的响应规律。结果表明，从年变化规律看，2000—2020年广东省年平均气温、年降水量呈微弱上升趋势，正增长区面积占比分别为86.8%、64.8%；日照时数呈下降趋势，负增长区面积占比为82.4%。植被NPP呈波动上升趋势，多年平均值为1011 g∙m⁻²，年增长值为6.7 g∙m⁻²∙a⁻¹，正增长区面积占全省面积的91.9%。其中，森林生态系统NPP多年平均值及正增长区占比均最高，分别为1107 g∙m⁻²、95.6%，湿地生态系统NPP多年平均值及正增长区占比均最小，分别为686 g∙m⁻²、89.5%。从影响程度看，植被NPP与温度、降水、日照时数均呈显著正相关关系，相关系数分别为0.81、0.48、0.68，均通过p=0.001的显著性检验，可见气温是对植被NPP影响最为显著的气候因子，其次是日照、降水。气温和日照时数对森林生态系统NPP影响最大、对湿地生态系统NPP影响最小，降水对农田生态系统影响最大、对湿地生态系统影响最小。从响应时间而言，NPP与气温、日照时数的相关系数均在当月达到最大，而NPP与降水量的相关系数在滞后1个月时达到最大，可见NPP对气温、日照时数的响应不存在滞后。从影响持续时间而言，气温与NPP的相关系数在当月到滞后2个月时均较高，日照时数与NPP的相关系数仅在当月较高，降水量与NPP的相关系数则在当月到滞后3个月时均较高，表明降水对NPP影响持续时间最长。

关键词: 净初级生产力, 气候因子, 生态系统, 时空变化, 响应