高原鼢鼠土丘对矮嵩草草甸植被演替及土壤营养元素的作用

INFLUENCE OF PLATEAU ZOKOR MOUNDS ON THE VEGETATION AND SOIL NUTRIENTS IN A ALPINE MEADOW

本文研究了矮蒿草草甸上高原酚鼠土丘的出现率及其对植被的覆盖状况,土丘高度的下降及其直径的变化,土丘植物地上生物量和土丘营养元素含量。高原鼢鼠土丘出现率为242个/只/年,合土壤干重为1023.82公斤/只/年,对植被的覆盖面积高达22.53平方米/只/年。土丘在地表滞留时间约1年,处于不同演替阶段植被区域内出现的土丘,其植物地上生物量间的差异显著。5月前,在原生植被区出现的土丘,经4个月后,土丘边缘形成环状富草区,士丘边缘至中心区形成环状贫草区,而土丘中心仍处于无草状况。在次生植被区上的土丘则无此现象。新土丘除速效钾的含量与对照区无显著差异外,速效氮、磷的含量显著地高于对照区。旧土丘土壤中的速效氮、磷、钾含量均低于新土丘,但氮、磷的含量仍高于对照区。

Effect of plateau zokor (Myospalax baileyi) mounds in alpine meadow was investigated by determining the sinking tendency of mounds, coverage of mounds, change of the aboveground biomass of plant on mounds and soil nutrient concentrations at H-aibei Research Station of Alpine Meadow Ecosystem, Academia Sinica, 1990. The result showed that mounds were formed at a ratio of 243 mounds/year per zokor which were equal to 1023.82 kg of the dry mass of soil. The mounds would be sinking within one year. The aboveground biomass of plant on the mounds which emerged on the area of primary vegetation was significantly higher than that of on the area of secondary vegetation. There were three cyclic areas under the mound region that had been coved by a mound, one with abundant species of plants existed at the edging of the mound, another area with poor species of plants was at the intermediate part of the mound, there was a no plant area in the centre of the mound. The soil of fresh and old mounds were higher in available nitrogen and phosphorus content than randomly-collected samples, but available potassium content was not different between the mounds and controls area. Aboveground biomass of plant surrounding mounds was significantly higher than controls area.