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31.
Mo Fatemi 《Biological conservation》2009,142(7):1461-1468
Wind-facilitated migration of new genotypes into small, geographically disjunct populations should buffer them against local extinction. Bertya ingramii, a monoecious, wind-pollinated shrub, is restricted to three populations in a 4 km2 area in eastern Australia. Populations are separated by deeply dissected gorges where it is unlikely that seeds are exchanged but where wind movement may facilitate pollen dispersal. Using 156 highly polymorphic ISSR markers, we found moderate genetic variation within and among populations of B. ingramii and less genetic diversity in a nearby and small population of the widespread Bertya rosmarinifolia. The smallest population of B. ingramii (<30 plants) had the highest genetic variation (65% polymorphic markers, Shannon Information Index = 0.30). AMOVA and a Bayesian analysis showed that molecular variance was equally distributed within and among populations suggesting that gene flow is as limited within as in among populations. Genetic distances between populations were only weakly explained by their relative geographic distances (mantel test, R2 = 0.21, P = 0.001) but the distribution of private bands, the departure from Hardy-Weinberg equilibrium, and a UPGMA tree showed that the smallest population of B. ingramii was generally more similar to an upstream population of B. rosmarinifolia. Thirty-eight percent of bands in this small population of B. ingramii were exclusively shared with B. rosmarinifolia. This covert hybridisation may have been an ancient event but may be responsible for contemporary declines in germination and establishment in B. ingramii. The conservation implications are amplified by the endangered status of B. ingramii. 相似文献
32.
神农架地区珍衡植物沿河岸带的分布格局 总被引:2,自引:0,他引:2
Due to the importance of riparian zone in maintaining and protecting regional biodiversity, increasingly more ecologists paid
their attentions to riparian zone and had been aware of the important effects of riparian zone in basic study and practical
management. In this study, 42 sampling belts (10 m×100m) parallel to the bank of Xiangxi River at different elevations in
Shennongjia Area were selected to investigate the riparian vegetation and rare plants. 14 species of rare plants were found
distributing in riparian zone, accounting for 42.4% of the total rare plant species in Shennongjia Area. The main distribution
range of the 14 rare plant species was the evergreen and deciduous mixed broadleaved forest at elevation of 1200–1800 m, where,
species diversity of plant community was the maximum at the moderate elevation. The analysis of TWINSPAN divided the 14 rare
species into 3 groups against the elevation, namely low elevation species group, moderate elevation species group, and high
elevation species group. The analysis of DCA ordination showed similar results to that of TWINSPAN. In the paper, the authors
discussed the reasons forming the distribution pattern of rare plant species, and pointed out that the important function
of riparian zone on rare plant species protection.
Foundation item: This project was supported by National Natural Science Foundation of China (NSFC39970123), and Changbai Mountain Open Research
Station, Chinese Acadamy of Science.
Biography: JIANG Ming-xi (1965-), male, associate professor in Wuhan Institute of Botany, Chinese Academy of Sciences, Wuhan 430074,
P. R. China
Responsible editor: Chai Ruihai 相似文献
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34.
Rare species have restricted geographic ranges, habitat specialization, and/or small population sizes. Datasets on rare species distribution usually have few observations, limited spatial accuracy and lack of valid absences; conversely they provide comprehensive views of species distributions allowing to realistically capture most of their realized environmental niche. Rare species are the most in need of predictive distribution modelling but also the most difficult to model. We refer to this contrast as the “rare species modelling paradox” and propose as a solution developing modelling approaches that deal with a sufficiently large set of predictors, ensuring that statistical models are not over-fitted. Our novel approach fulfils this condition by fitting a large number of bivariate models and averaging them with a weighted ensemble approach. We further propose that this ensemble forecasting is conducted within a hierarchic multi-scale framework. We present two ensemble models for a test species, one at regional and one at local scale, each based on the combination of 630 models. In both cases, we obtained excellent spatial projections, unusual when modelling rare species. Model results highlight, from a statistically sound approach, the effects of multiple drivers in a same modelling framework and at two distinct scales. From this added information, regional models can support accurate forecasts of range dynamics under climate change scenarios, whereas local models allow the assessment of isolated or synergistic impacts of changes in multiple predictors. This novel framework provides a baseline for adaptive conservation, management and monitoring of rare species at distinct spatial and temporal scales. 相似文献
35.
珍稀濒危植物领春木愈伤组织的培养 总被引:2,自引:0,他引:2
以领春木茎段为外植体 ,成功地诱导出了愈伤组织 ,将获得的愈伤组织用于适宜增殖培养条件的研究。结果表明 :MS和 1/ 2MS作为愈伤组织诱导基本培养基较为适宜 ;愈伤组织增殖培养以MS培养基 +NAA 2mg/L + 6 BA 0 .1mg/L ,pH值 5~ 6较为合适。 相似文献
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38.
通过黑化雉鸡 (Melanisticmuckedpheasant)和大型环颈雉鸡 (Jumboringneckedpheas ant)的正交和反交 ,以及F1 中进行自交 ,观察F1 和F2 中羽色性状的表现和分离比例。试验结果表明 ,黑化雉鸡羽色性状对于环颈雉鸡羽色的遗传方式是显性遗传 ,而且显性是完全的 ;黑化雉鸡羽色性状也由常染色体上一对等位基因M来控制的 ,并不存在显性致死现象 相似文献
39.
提高我国山鸡种蛋人工孵化技术的试验研究 总被引:3,自引:0,他引:3
使用我国山鸡种蛋进行了3个人工孵化试验,每个试验设2次重复,测定在不同的孵化温度与相对湿度条件下,即高温度—低湿度、低温度—高湿度与恒温—恒湿,对胚胎发育的死亡率、受精蛋孵化率、健雏率、不同胎龄胚蛋的失重率及雏山鸡出生重的影响。试验结果表明:我国山鸡种蛋在不同的孵化温度、相对湿度的人工孵化条件下,其胚胎的死亡率、受精蛋孵化率与健雏率均有显著差异(P<0.05),而在雏山鸡出生重等方面差异不显著(P>0.05)。为我国山鸡种蛋的人工孵化提供了技术材料与数据。 相似文献
40.
探讨了不同稀土肥料在日光温室中草莓的增产效果,结果表明:采用稀土肥料浸根,浓度以200~300 mg/kg为宜,喷施浓度以300~400 mg/kg为宜。 相似文献