山西亚高山草甸植被生物量的地理空间分布

Geographical distribution of vegetation biomass of subalpine meadow in Shanxi Province

以山西省境内分布的典型亚高山草甸为对象,采用收获法获取植被生物量数据,结合经度、纬度和海拔3个地理因子,分析总生物量(TB)、地上生物量(AGB)、地下生物量(BGB)及根冠比(R/S)沿不同地理梯度的变化规律,从群落水平上探究山西亚高山草甸植被生物量的地理空间分布特征。结果表明:(1)TB、AGB、BGB在地域上表现较大变异。AGB变异最大,在32.50~756.00 g·m-2;BGB次之,变化范围为140.50~1586.50 g·m-2;TB波动最小,在248.25~2342.50 g·m-2。(2)TB随海拔升高显著减小(P<0.05),随经度增加缓慢增大(P>0.05),随纬度增加略微减小(P>0.05),在1700~1800 m、113.4°E—113.85°E、35°N—35.5°N处最大(平均为896 g·m-2)。(3)AGB随纬度增加、海拔升高显著减小(P<0.001),随经度增加逐渐增大(P<0.05),在1700~1800 m、112.05°E—112.5°E、35°N—35.5°N处最大(平均为366.06 g·m-2)。(4)BGB随纬度增加呈"降低-升高-降低"的变化趋势,整体略有增大(P>0.05),随经度增加也略有增大(P>0.05),而随海拔升高显著增大(P<0.05),在3000~3100 m、113.4°E—113.85°E、35°N—35.5°N处最大(平均为745.63 g·m-2)。(5)R/S随纬度增加、海拔升高显著增大(P<0.05),随经度增加略有增大(P>0.05);与纬度、海拔呈显著的幂指数函数关系(P<0.05),且表现为等速增长(幂指数平均为1.025)。RDA分析结果表明,在一定范围内,对亚高山草甸植被不同生物量特征影响较大的为纬度和海拔因子,最小影响因子是经度,地上生物量与经纬度和海拔均呈显著的负相关,生物量更多地分配到地下部分。

In this study, we selected typical subalpine meadow distributed in Shanxi Province to explore the geographical distribution of vegetation biomass of subalpine meadow at the community level. After biomass was harvested, the variation of total biomass （TB）, aboveground biomass （AGB）, below-ground biomass （BGB） and root：shoot ratio （R/S） were analyzed at different geographical gradients （longitude, latitude, and altitude）. The results showed that TB, AGB, and BGB substantially varied across the region. The variation was the largest for the AGB with a range of 32.50-756.00 g·m^-2, followed by the BGB with a range of 140.50-1586.50 g·m^-2. The variation in TB was the smallest with a range of 248.25-2342.50 g·m^-2. The TB decreased significantly with altitude （P〈0.05）, whereas increased slowly with longitude （P〉0.05）, and slightly decreased with latitude （P〉0.05）. The largest TB was found at 1700-1800 m, 113.4-113.85°E, 35-35.5°N （with an average of 896 g·m^-2）. The AGB decreased significantly with increasing latitude and altitude （P〈0.001）, and gradually increased with longitude （P〈0.05）. The largest AGB was found at 1700-1800 m, 112.05-112.5°E, 35-35.5°N （with an average of 366.06 g·m^-2）. The BGB showed a trend of “decreaseincreasedecrease” as the latitude increased, but increased slightly overall （P〉0.05）, slightly increased with longitude （P〉0.05）, and increased significantly with the increases of altitude （P〈0.05）. The maximum BGB was found at 3000-3100 m, 113.4-113.85°E, 35-35.5°N （with an average 745.63 g·m^-2）. The R/S increased significantly with increasing latitude and altitude （P〈0.05）, slightly increased with longitude （P〉0.05）, and showed a significant exponential function with latitude and altitude （P〈0.05）, characterized by isometric growth （average power exponent of 1.025）. Results from redundancy analysis showed that latitude and altitude had greater impacts on the biomass of subalpine meadow, while longitude had less impact. The AGB was negatively correlated with longitude, latitude, and altitude. Subalpine meadow allocated more biomass to belowground parts.