河水漫溢对塔里木河下游荒漠河岸林地表植被与土壤种子库的影响

采用种子萌发法,研究了河水漫溢对塔里木河下游荒漠河岸林地表植被与土壤种子库的影响.结果表明：塔里木河下游漫溢区地表植被分属8科13属14种，非漫溢区为10科21属26种植物；与非漫溢区相比，漫溢区地表植被中出现了一些浅根系和喜湿的草本植物；漫溢区单位面积物种数、植被盖度、植株密度、物种多样性指数和丰富度指数均比非漫溢区有明显增加.漫溢区土壤种子库中有物种19种，比非漫溢区增加了5种；漫溢区土壤种子库总密度比非漫溢区增加了3.94倍；与非漫溢区相比，漫溢区1年生草本植物种子的比例增加了23.07%,而灌木植物种子比例减少了20.99%；多年生草本的变化则不明显；河水漫溢提高了土壤种子库的生物多样性.漫溢区和非漫溢区土壤种子库与地表植被的共有物种分别为18和9种，土壤种子库与地表植被的相似性系数分别为0.842和 0.667.

Characteristics of standing vegetation and soil seed bank in desert riparian forest in lower reaches of Tarim River under effects of river-flooding.

An investigation was made on the standing vegetation and soil seed bank in desert riparian forest in lower reaches of Tarim River under effects of river-flooding. The results showed that the standing vegetation in non flooded and flooded sites was composed of 14 species in 13 genera of 8 families, and 26 species in 21 genera of 10 families, respectively, and some shallow rooted and hygrophilous species were recorded in flooded sites. The indices per unit area plant species number, vegetative coverage, plant density, and species diversity of the vegetation were all higher in flooded than in non flooded sites. The species number of the soil seed bank in flooded sites was 19, with 5 species more than that in non flooded sites, and the seed bank density in flooded sites was 2.94 times higher than that in non flooded sites. The proportion of annual herbaceous species seeds in flooded sites increased by 23.07% while that of shrub species seeds decreased by 2099%, compared with those in non-flooded sites, and the proportion of perennial herbaceous species seeds had less difference between these two sites. River-flooding increased the diversity of soil seed bank. In flooded and non-flooded sites, the co-occurrence species in seed bank and in standing vegetation were 18 and 9, with the similarity coefficients of species composition between soil seed bank and standing vegetation being 0.842 and 0.667, respectively.