Effects of genetic impoverishment on plant community diversity
Effects of genetic impoverishment on plant community diversity
复制标题
DOI：
10.1046/j.1365-2745.2003.00804.x
复制
发表时间：
2003-10-01
影响因子：
5.5
通讯作者：
Grime, JP
中科院分区：
文献类型：
--
作者：
Booth, RE;Grime, JP
从北德比郡Cress-Brookdale古老石灰岩牧场的11个长期共存的草本植物种群中随机抽取1个已建立的个体进行克隆繁殖，以产生足以产生36个物种组成相同但遗传多样性差异很大的模式群落的遗传相同个体。在一种处理中，每个物种的所有个体在基因上都是独一无二的。第二个包含每个物种的四个随机选择的基因类型。3在5年的时间里，这些群落被允许在含有天然Rendzina土壤的微型宇宙中发展，并暴露在模拟放牧和践踏的标准化制度下。通过去除来自种子库和种子雨的花、未成熟的种头和幼苗来维持处理。4在试验期间，5个冠层优势种和5个从属群落之间的区别迅速发展，这一过程使植被结构与克雷斯布鲁克达尔的植被结构非常相似。5所有3个处理都出现了物种多样性的逐渐丧失，但到第五个生长季结束时，遗传多样性最多样化的群落的物种多样性更高。6在5年的时间里，36个群落的排序显示，4-基因和16-基因群落的物种组成逐渐趋同，这种影响在后者中发展得更强烈。在1-基因型群落中没有观察到类似的过程，这表明当地社区不同物种的特定基因型之间的相互作用可能是决定成熟草地群落的可预测组成的机制的重要组成部分。7得出的结论是，在本实验条件下，组成物种内的遗传多样性降低了物种多样性的下降速度。诸如更强的抗病能力和缓和的竞争相互作用等因素在这种影响中的相对重要性仍然不确定。
1 Established individuals removed at random from populations of 11 long-lived herbaceous species coexisting in a local area of ancient limestone pasture at Cress-brookdale in North Derbyshire were subjected to clonal propagation to produce stocks of genetically identical individuals sufficient to create 36 model communities identical in species composition but widely contrasted in genetic diversity.2 Three levels of genetic diversity were imposed. In one treatment, all individuals of each species were genetically unique. The second contained four randomly selected genotypes of each species. In the third, there was no genetic diversity in any of the species but each community contained a unique combination of genotypes.3 Over a period of 5 years the communities were allowed to develop in microcosms containing natural rendzina soil and exposed to a standardized regime of simulated grazing and trampling. The treatments were maintained by the removal of flowers, immature seed-heads and seedlings originating from the seed-bank and seed rain. Point quadrat surveys were used to monitor changes in species composition and diversity in the three experimental treatments.4 During the experiment a distinction rapidly developed between five canopy dominants and five subordinates, a process that caused the vegetation structure to closely resemble that occurring at Cressbrookdale.5 A gradual loss of species diversity occurred in all three treatments but by the end of the fifth growing season species diversity was higher in the most genetically diverse communities.6 Ordination of the 36 communities at intervals over a 5-year period revealed a gradual convergence in the species composition of the 4-genotype and 16-genotype communities and this effect was more strongly developed in the latter. A comparable process was not observed in the 1-genotype communities, suggesting that interaction between particular genotypes of different species in local neighbourhoods may be an essential part of the mechanism that determines the predictable composition of a mature pasture community.7 It is concluded that, under the conditions of this experiment, genetic diversity within component species reduced the rate at which species diversity declined. The relative importance in this effect of factors such as greater disease resistance and moderated competitive interactions remains uncertain.