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不同培养液中3种藓类光合色素含量比较 总被引:3,自引:0,他引:3
光合色素是客观反映植物利用光照能力的一类重要指标,往往可以作为判断植物光合生理能力、反映环境胁迫状况的重要指标[1-3]. 相似文献
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为了解人工林生态系统的持水性特征,采用野外实地观测和室内浸水法对3种主要人工林下苔藓和凋落物层(未分解层、半分解和分解层)的持水特性进行了研究。结果显示:①苔藓层蓄积量以混交林最高(0.52 t· hm-2),柳杉林最低(0.10 t· hm-2);凋落物层均以楠木林最高,柳杉林最低。②柳杉和水杉林间、楠木和混交林间苔藓层最大持水性差异均不明显;柳杉和水杉林凋落物半分解层和已分解层最大持水率大于未分解层,而楠木和混交林则是未分解层大于半分解层和已分解层。③各林分苔藓层吸水速率到2h后均趋于平缓,凋落物半分解层和已分解层与未分解层均在6 h后趋于平缓,苔藓和凋落物层吸水速率与浸泡时间符合V=kt b 关系,经检验达显著水平。 相似文献
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Analysis of variance and redundancy analysis were used to study the effects of mowing regime and herb canopy structure on the bryophyte layer of a calcareous grassland in southern Belgium. Species richness in mown and control plots did not significantly differ. In control plots, a number of grassland species were able to survive within a grassy-shrubby fringe 15 years after shrub cutting. This suggests that there might be a time-lag of at least 20 years before cessation of mowing results in a significant decrease in species number per m2. Mown plots were mostly characterized by the almost complete cover of large pleurocarps. Mowing resulted in almost continuous herb and moss layers that were unfavourable for a number of annual bryophytes, many of which are of high conservation interest. It is suggested that grazing, which increases the number of species, especially the number of pioneers, is likely to be more beneficial to bryophytes. 相似文献
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Forest integrity has been proposed as one conservation endpoint that integrates desirable characteristics such as natural biodiversity, stand structure and continuity. Although its defining criteria are still under discussion, any surrogates must effectively represent or predict their status, and be easier to measure than the criteria themselves. Bryophytes have been proposed as such surrogates, because they are important components of forest integrity, and considerable research indicates that some groups are sensitive to the changes associated with specific forest management regimes. The objectives of this paper are (1) to review the issues in determining indicators of forest integrity, including desirable qualities in such indicators, (2) to review the state of knowledge concerning bryophytes as components of forest integrity (i.e. their responses to forest management practices), and (3) to assess bryophytes as potential indicators of forest integrity, in terms of both qualities desirable in indicators and our understanding of bryophyte response patterns. Although bryophytes possess some characteristics that suggest potential indicator value, many challenges prevent their reliable application. I highlight key areas in which research is required to identify operational bryophyte indicators of forest integrity. Along with a standardized protocol to select and calibrate such indicators, we urgently require strategic research to compile data on undisturbed reference forests on which to base selection of endpoints; species-specific ecological tolerances, with consideration of complex interactions; mechanisms of response to disturbance, with consideration of temporal aspects; population viability thresholds; and recruitment effects on community assembly. Whether we succeed in finding bryophyte indicators of forest integrity, this research would also provide the data to monitor and interpret the integrity of the bryophyte community. 相似文献
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Nunik S. Ariyanti Sri S. Tjitrosoedirdjo S. Robbert Gradstein 《Biological conservation》2008,141(10):2516-2527
Forest disturbance and transformations into agricultural land alter tropical landscapes at drastic rates. Here, we investigate bryophyte assemblages on trunk bases in natural forest, selectively logged forest and cacao agroforests that are shaded by remnants of natural forest in Central Sulawesi. Overall, bryophyte richness per site did not differ between forest types. However, mosses and liverworts reacted differently in that moss richness was lowest in cacao agroforests, whereas liverwort communities were equally rich in all forest types. In terms of cover, mosses remained unaffected while liverwort cover decreased significantly in disturbed forest. Species composition of bryophytes clearly changed in cacao agroforests as compared to natural forests and selectively logged forests. In particular some drought-sensitive species were rare or absent in cacao agroforests and were replaced by drought-tolerant ones, thus underlining the importance of microclimatic changes. Moreover, differences in bryophyte species composition between large and small trees were only pronounced in cacao agroforests, presumably due to concomitant changes in stemflow of precipitation water. In conclusion, the bryophyte assemblages of selectively logged forests and cacao agroforests were as rich as in natural forest, but species turn-over was particularly high towards cacao agroforests probably due to microclimatic changes. Maintenance of shade cover is crucial to the conservation of the drought-sensitive forest species. 相似文献
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调查测定不同林型的苔藓地被层的生物量和持水量,结果表明,苔藓在杜鹃林内的生物量最大,在人工落叶松林内最少。苔藓层具有接近自身重量5倍的持水量能力,苔藓层在森林系统中能起到维持水分供应平衡的作用。保护冻土层的绝缘作用和对降水具有缓冲滞留作用。并提出保护和深入研究苔藓的建议。 相似文献
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新疆苔藓植物的染色体观察 总被引:1,自引:0,他引:1
报道了进行苔藓植物细胞学研究的方法和5种新疆产的苔藓配子体生长点细胞有丝分裂中期的染色体数:(1)银藓Anomobryum filiforme(Dicks.)Hunsn.,n=10;(2)细叶真角藓Bryum capillare L.exHedw.,n=10;(3)柔叶真藓Bryum cellulare Hook.,n=10;(4)牛角藓Cratomeuron filicinum(Hedw.)S 相似文献
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Perpetua A.M. Turner Jamie B. Kirkpatrick Emma J. Pharo 《Biological conservation》2011,144(12):2951-2957
Maintenance of old growth forest has been argued to be important for the future of many bryophyte species, but there has been no empirical test of this proposition. Bryophytes constitute much of the plant biodiversity in Tasmanian tall open-forests dominated by Eucalyptus regnans and Eucalyptus obliqua. These forests have a low level of protection in their old growth stage. We ask whether if there is a concentration of bryophyte species in particular forest age classes and assess its significance for biological conservation. The bryophyte species at 99 forest sites were recorded and related to young, mature and old growth age classes using ANOVA. Only two bryophyte taxa were confined, with statistical confidence, to one of these classes. Succession in bryophyte assemblages takes the relay floristics form, with a few highly frequent species in the young forest, most of which do not persist in later stages, a large number of species establishing in middle-aged forests, some dying out with their short-lived hosts by the time of the old growth forest stage, and liverworts becoming more prominent with age. Species concentrated in the old growth phase of these eucalypt forests have all been recorded from secure reserves in this and other vegetation types. If present patterns of land use continue, and no extensive wild fires occur in the reserved old growth forest, almost all bryophyte species of E. regnans and E. obliqua mixed forest are likely to survive. This may not be the case in other regions of the world, where reservation may be poorer than in Tasmania. 相似文献