The relationship between species diversity and aboveground biomass may be affected by environmental conditions and anthropogenic activities and is one of the central topics in ecological research.However,little is known about the relationship between the biodiversity and biomass of sandy plants during community succession in semi-arid deserts.In the Horqin Sandy Land of Inner Mongolia in China,vegetation restoration occurs under proper management regimes in fragile environmental conditions,e.g.,enclosing and non-grazing.During the process of restoring succession,shifting,semi shifting or semi-fixed,and fixed sandy dunes correspond to early,middle,and late succession phases.Therefore,a field experiment was performed to examine the aboveground biomass and species diversity of sandy communities during the process of restoring succession.In early April 2014,six communities that corresponded to succession times of 1,3,5,12,15,and 20 years were selected as experimental sites.At each site,three parallel 200m line transects (20 m apart) were established along a sandy dune (across the windward slope,dune crest,and leeward slope).For each transect,20 sampling points of 1 m × 1 m were established at 10m intervals.At each of the 360 sampling points,species composition,coverage,height,and density were surveyed;whereas aboveground biomass was measured using a level cutting method,and the dry weight of the biomass was measured after drying in an oven at 85 ℃ for 24 h.The frequency of each species was calculated at each of the six sites,based on the frequency of occurrence among the 60 sampling points.(1) The number of plant species increased by 400％ from the shifting sandy dune to the fixed dune,and annual herbaceous plants were dominant in each community,although perennial species increased with succession.In the shifting sandy dune community,the dominance of the Chenopodiaceae was the most exaggerated,and this level of dominance gradually decreased in the semi-fixed and fixed sandy dunes.Meanwhile,the richness and dominance of grass species gradually increased during the process of restoring succession.There was a significant difference among the aboveground biomass of six communities (F=18.926,n=360,P＜ 0.001),and the aboveground biomass increased by 580％ from the shifting sandy dune to fixed sandy dune.(2) The Simpson,Shannon-Wiener,and evenness indices gradually increased along the restoring succession gradients.(3) Regression analysis indicated a marked relationship between aboveground biomass and species diversity.The fitting curve was a negative quadratic or a single peak function.The results of the present study support the single-peak model of the relationship between biodiversity and productivity of plant communities,with maximum biodiversity occurring at an intermediate level of plant productivity.%生物多样性与生产力的关系是当前生态学中研究的重点之一,以科尔沁沙地为研究对象,研究了沙地植被恢复演替进程中物种多样性与地上生物量的关系.结果表明:(1)科尔沁沙地植被恢复演替过程中,物种数量逐渐增加,从流动沙丘的6种到固定沙丘的30种,增加了4倍.一年生草本植物在各群落中占绝对优势,但随着演替的进行,生活型呈现多样化,多年生植物种类明显增加.藜科植物在流动沙丘阶段优势度明显,之后逐渐下降;禾本科植物的种数和优势度逐渐增加,在群落中的地位逐渐增强.多重比较表明,群落的地上生物量存在显著差异(F=18.926,n=360,P＜0.001),从流动沙丘到固定沙丘(3个恢复阶段的均值计算)地上生物量增加了580％.(2)随着演替的进行,群落Simpson指数、Shannon-winner指数和均匀度指数均呈现增加的趋势.(3)回归分析显示,群落物种多样性和生物量之间存在显著的负二次函数关系即单峰型函数关系,表明中等生产力水平物种多样性较高.
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