<正>以上海市公益林为研究对象，运用层次分析法构建了适用干上海的公益林生态效益评价指标体系。该指标体系分为总目标层、准则层、指标层，其中准则层7项，指标层共包含30个指标。从权重看，改善小气候、净化空气和防风减噪功能的权重明显高于其他生态功能，分别为0.24、0.2、0.19，这一结果与上海高度工业化特点和城市未来发展的目标相适应。

The effect of water depth gradient on the growth and nutrient removal rate of the submerged macrophytes Potamogeton malaianus, a dominant species in Taihu Lake, was examined in an outdoor pond experiment. At the beginning of the growth period, lower water depth increased the grewth rate of P. malaianus. The growth rate reached 2.04 cm/d at the water depth about 60 cm,while 0.88 cm/d at the water depth about 180 era. During 82 days growth period, the stem height of P. malaianus was 180 cm and the growth rate was 2.04 Cm/d, while the stem height was 86 cm and the growth rate reached only 1.07 cm/d at 60 cm water depth. The stem height and the water depth was positive correlation along the water depth gradient. The biomass of P. malaianus ranged from 810 g/m3 to 2 941 g/m3. The biomass and stem height increased with the water depth. The aboveground concentration of nitrogen and phosphorus of P. malaianus was 86.43 mg/g and 5.12 mg/g, respectively at the 100 cm water depth. The TN and TP removal rate also reached the highest value of 87.6 mg/g and 40. 1 mg/g, respectively at the 100 cm water depth. Compared with the TN removal rate, TP removal rate was relatively low in the different water depth gradient. TN removal rate of P. malaianus was 2.87 times of its TP removal rate. The biomass and density of P. malaianus showed an active response to the water depth gradient. The experiments showed the optimal water depth on the growth of P. malaianus and its TN and TP removal rate was 100 cm.