高寒草甸植物群落中物种丰富度与生产力的关系研究

 以物种组成较为复杂的青藏高原东部地区典革高寒草甸植物群落为背景，从不同的时间和空间尺度水平研究了植物群落中物种丰富度与生产力（地上部生物量）关系的基本模式。结果表明：1）总体而言，高寒草甸植物群落中物种丰富度与生产力的关系呈对数线性增加关系，这实际上是空间和时间尺度放大时在时间和空间尺度的相互作用下高寒草甸植物群落中物种丰富度与生产力关系的一种总体模式；2）随着研究的时间和空间尺度的改变，物种丰富度与生产力的关系会发生一些相应的变化，但空间尺度比时间尺度对物种丰富度与生产力的关系造成的影响更为显著，这可能

RELATIONSHIP BETWEEN SPECIES RICHNESS AND PRODUCTIVITY IN AN ALPINE MEADOW PLANT COMMUNITY

There has been a rapidly increasing interest in the effects of species richness on ecosystem productivity. In order to search for a general species richness_productivity pattern and find the mechanisms underlying the pattern, ecologists have undertaken intensive empirical studies. Due to different ecological contexts (such as characteristics of surrounding environment, spatial and temporal scales of investigation) in a variety of experimental studies, positive, negative, and non_existent diversity_productivity relationships have been observed. The species richness_productivity connection still remains unclear. Experimental manipulated studies have generated a considerable amount of criticism based upon their experimental methodology, analysis, and general conclusions. In this paper, we use data collected from a typical natural alpine meadow to explore the general species richness_ productivity pattern. Over a two_year period, we recorded the total number of species present, and estimated and measured percent coverage of each species and its aboveground biomass in 80 permanent plots three times in each growing season. Ecosystem productivity was estimated as aboveground biomass. We tested whether the species richness_productivity relationship is monotonic and whether the relationship varies as the spatial and temporal scales change. Our results showed that:1)There is an overall log_linear increase in species richness_productivity pattern; it actually reflected an overall species richness_productivity pattern of alpine meadow plant community in the interaction of spatial and temporal scales on enlarged temporal and spatial scales. 2)The species richness_productivity relationships change with temporal and spatial scales, but the influence of spatial scales on the relationship is more significant than that of temporal scales. This may be due to the short growth season. Based on the above results, we suggest that the differences in temporal and spatial scales may cause non_consistent species richness_productivity relationship in varieties of experimental studies.