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41.
在五种不同恒温条件下,观察了黄岗仓花蝽各世代的存活率及成虫的繁殖力。结果表明,该虫的世代存活率及成虫的繁殖力均以28℃下的为最高,36℃下的为最低。进而根据不同温度条件下的实验数据,组建了该虫实验种群生命表,并用数学模型描述了温度与种群增长的关系,可用以预测该虫在不同温度下的种群增长趋势。 相似文献
42.
温度对微小花蝽实验种群增长的影响 总被引:2,自引:0,他引:2
实验室饲养观察结果表明,在15-35℃温度范围内,随温度升高,微小花蝽的发育速率加快,成虫寿命缩短,在25℃下的世代存活率最高。根据实验数据计算出该虫的卵期发育起点温度为13.6℃,有效积温为1=55.15日.度;若虫期发育起点温度为8.0℃,有效积温为270.1日.度。组建了25℃和30℃两种温度下的该虫的实验种群生命表。 相似文献
43.
The impacts of blanket peatland management on water tables, near‐surface macropore flow and saturated hydraulic conductivity were investigated using automated dipwells and mini‐disc tension infiltrometers. Three neighbouring hillslopes which were undisturbed, drained and restored by drain blocking were studied. Mean water table depths at the undisturbed sites were slightly shallower than at the restored site and water tables at both sites were significantly shallower relative to the drained treatment. Through time, however, the water table at the restored treatment behaved in a markedly different way to that at the undisturbed site. Water tables reached the peat surface for only 2% of the time for the drained and restored treatments compared to 18% for the undisturbed treatment. The proportion of runoff flowing through macropores in the near‐surface layers of the peat was found to be large (≥60%) across all three treatments, yet functional macroporosity was found to be significantly greater in the undisturbed peat relative to the two other treatments. Meanwhile, saturated hydraulic conductivity was found to be significantly higher at the restored treatment relative to the two other treatments, with mean conductivities ca. 1.5 times greater, suggesting a form of heightened soil–water interaction. Combined, the results indicate that although restoration by ditch blocking may result in a relatively successful water table recovery, there may not be the full reinstatement of peatland hydrological processes. 相似文献
44.
45.
Fish eggs and larvae are often subject to very high mortality, and variation in early life survival can be important for population dynamics. Although longnose suckers (Catostomus catostomus) are widespread in northern North America, little is known about their early life history. We examined fecundity and early larval survivorship during sucker spawning events in three small Lake Michigan tributaries. Although egg deposition varied 25% among spawning events, estimated larval export to the lake varied over 25,000‐fold from around 1000 to 26 million. Based on variation in environmental conditions across years, it appears that spring flow and temperature may be important determinants of egg survival to larval outmigration. Larval age data suggest that most individuals that survived to outmigration hatched during a 2‐day period despite adult spawning across at least 10 days. Most larvae spent <2 weeks in the stream and emigrated around the time of transition from endogenous to exogenous feeding before substantial growth occurred. In two of three cases, larvae drifted exclusively at night; however, high drift rates occurred during both day and night in the case where larvae were very abundant, suggesting density‐dependent drift behaviour. Our results indicate that survival in tributary streams from egg deposition to larval export is highly variable in longnose suckers. These large differences in early life survival may translate into variability in recruitment, thereby influencing population structure and dynamics. 相似文献
46.
广州水岸公共景观的变更影响着城市及人们的公共生活。本文通过分析东濠涌的沿岸公共活动变迁及其2010年的改造实例,探讨水岸环境与沿岸公共生活类型之间的关系。 相似文献
47.
Miyazono S, Aycock JN, Miranda LE, Tietjen TE. Assemblage patterns of fish functional groups relative to habitat connectivity and conditions in floodplain lakes.Ecology of Freshwater Fish 2010: 19: 578–585. © 2010 John Wiley & Sons A/S Abstract – We evaluated the influences of habitat connectivity and local environmental factors on the distribution and abundance patterns of fish functional groups in 17 floodplain lakes in the Yazoo River Basin, USA. The results of univariate and multivariate analyses showed that species–environmental relationships varied with the functional groups. Species richness and assemblage structure of periodic strategists showed strong and positive correlations with habitat connectivity. Densities of most equilibrium and opportunistic strategists decreased with habitat connectivity. Densities of certain equilibrium and opportunistic strategists increased with turbidity. Forested wetlands around the lakes were positively related to the densities of periodic and equilibrium strategists. These results suggest that decreases in habitat connectivity, forested wetland buffers and water quality resulting from environmental manipulations may cause local extinction of certain fish taxa and accelerate the dominance of tolerant fishes in floodplain lakes. 相似文献
48.
吴正荣 《云南农业大学学报(自然科学版)》2010,4(5):100-103,114
"儒士"自觉地承担着儒家的社会意识,而"僧人"则以完成生命的超越为己任。在三教合流的传统中,"儒士"和"僧人"的内在文化构成并不具备严格意义上的界分,常常互有融含。故而,论述时只能抽象出其"共相"意义上的概念,各置于"儒""释"系统中剖析其最高价值追求,得出儒士诗重社会伦理,而僧人诗则重解构文化局限,求证生命本源的结论。 相似文献
49.
对农村社区公益性文化建设中几个问题进行了阐释,指出推进农村社区公益性文化建设,应重视农村权威人物发挥积极作用,预防其消极作用;应重视农民工对乡村社会的影响力,引导农民工对农村社区建设发挥积极作用;应重视农民闲暇生活,用先进文化占领这一重要阵地。 相似文献
50.
Abstract – The persistent effects of embryonic temperature stress and individual parentage on fry swimming performance were examined in a cross‐fertilisation experiment using sockeye salmon (Oncorhynchus nerka). A fixed‐velocity test of burst swimming was used to assess the endurance capacity and behavioural performance of individual fry from 10 offspring families incubated at 12, 14 or 16 °C to hatch and then reared through yolk absorption and exogenous feeding stages in a common posthatch environment (average 6.9 °C). Fry burst swim time (BST) was influenced by an interaction between incubation temperature and family identity. Average BST was longer for fry from the 12 °C prehatch treatment compared to 14 and 16 °C, although differences were largely attributable to temperature effects on average fry size. Behavioural observations revealed that fish incubated at 16 °C performed more poorly, having a larger proportion of individuals that required stimulation to swim, fatigued more frequently or were classified as ‘nonswimmers’. Within all three incubation temperature treatments, mean BST varied significantly among offspring families, independent of fry mass and length. An interesting relationship was observed within the 16 °C treatment, whereby families with higher survivorship were characterised with lower mean BSTs. Collectively, these findings demonstrate that exposure to high temperatures in early sockeye salmon development can result in persistent, parentally mediated effects on fry performance. As such, these results provide important insight into how elevated temperature events during egg incubation may affect early life history selection processes and survival in stages beyond when the stressor is experienced. 相似文献