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Brigitte Poulin 《Biological conservation》2009,142(3):689-1609
The vulnerable Eurasian bittern Botaurus stellaris has recently benefited from conservation actions in several European countries. The Camargue in Mediterranean France holds 8000 ha of reed marshes and 50% of the French bittern population estimated at 300-350 booming males. Although reed cutting in Europe is a current practice, we provide the first analyses on habitat selection relative to reed exploitation. The contribution of reed harvesting and water management was assessed at a fine scale (digitized aerial photographs of 50-cm resolution) based on multi-modelling data analyses. GLMs applied to random and bittern points of 50-m radius showed that bitterns preferred areas with less than 10% open water enclosing 1-year reeds. Only in harvested reedbeds had the water management a significant impact on habitat selection, with bitterns avoiding areas dried during less than two months and flooded since less than 8 months. Water edge played a role in non-harvested reeds only, with bittern seeking for areas with the highest ratio water edge to open water. Although reed cutting is generally considered as detrimental in the short term, two 4-year experiments showed a marked increase in bitterns the first spring after cutting was interrupted. Based on these results, we propose various management scenarios that conciliate economic constraints of reed harvesters and protection of Eurasian bittern populations. 相似文献
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Tiejun Zhang Yunwen Wang Xianguo Wang Quanzhen Wang Jianguo Han 《Soil & Tillage Research》2009,105(1):143-148
Soil organic carbon and nitrogen are key elements of sustainable agriculture. Converting forest land and grassland to arable land is known to decrease the content of soil organic carbon (SOC), whereas converting land under annual crops into perennial grasslands has the potential to increase organic C and N sequestration, an assumption tested in this study. Compared to the levels in reed meadows, SOC and total nitrogen (TN) stocks in the top layer of 2489 Mg soil ha−1 (about 0–15 cm depth) significantly increased 3 years after the conversion, despite a slight decrease numerically in the first year following the conversion. And the mass of light fraction organic carbon (LFOC), total extractable carbon (TEC), humic acid carbon (HAC), and fulvic acid carbon (FAC) stocks all decreased significantly in the first year in the top layer but recovered after 3 years. In the deeper layer of 2549 Mg soil ha−1 (about 15–30 cm depth), however, the levels of SOC and heavy fraction organic carbon (HFOC) stocks began increasing from the first year itself. During the period of 1–10 years after the conversion, the degree of humification rate (HR) for the deeper layer were consistent, averaging 30%, whereas the same parameters in the top layer stabilized after 3 years at 33%. After 10 years of conversion, the soil recorded higher levels of SOC and TN stocks, used as indicators in this study, than those that had prevailed in the reed meadows, demonstrating the positive combined effects of the conversion on the retention of atmospheric C-CO2 in the soil. This study suggests that proper management of alfalfa fields can maintain or even improve chemical and physical quality of converted reed meadows soils. 相似文献
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[目的]研究微波、超声和碱液预处理对芦苇秸秆木质素的降解效果。[方法]设计Plackett-Burman试验,使用超声微波萃取仪以碱液为溶剂对芦苇秸秆进行处理,通过纤维分析仪测定木质素含量变化,分析了各处理因素在木质素降解中的作用。[结果]通过Minitab软件分析木质素降解率与处理条件的关系,发现碱液浓度为唯一显著的影响因素,液料比和微波时间也有一定作用。[结论]确定了碱液为主、微波为辅的芦苇秸秆木质素降解手段,为芦苇秸秆的预处理应用奠定了基础。 相似文献
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虉草的研究进展 总被引:5,自引:0,他引:5
从生物生态学特性、饲用价值及影响因素、品种选育、栽培与利用等方面对国内外饲用虉草(Phalaris arundinacea L.)研究进行综述。虉草属生长高大、多叶、高产的多年生冷季型禾本科牧草,具有优良的农艺性状和较高的营养价值,其根系强大,既抗旱又耐湿耐寒;除了种子,还可以根茎或分株进行营养繁殖,乃至茎节也可生根并长出枝条;虉草群落一但建成其竞争力很强,并迅速形成单优势种群落;虉草的高生物碱含量影响其饲用价值,通过育种可降低其生物碱含量,提高消化率;虉草种子在成熟前易脱落,栽培品种最适采种期是开花后16—18 d,野生种群是11—13 d;虉草属是高度自交不育植物,在种子生产中仅有少量自交种子;其育种目标是在改善适口性的同时,提高种子保持能力以及种子和饲草产量;虉草具有持续高产和吸收氮素的能力,因此很适合施有机肥或氮肥;虉草可用于放牧、青贮和调制干草,年刈割3~4次,干物质生产效率最高,放牧时,要保持草层高度不超过30 cm,适宜留茬高度为7~10 cm。最后,对我国在虉草研究中亟待解决的问题进行了讨论。 相似文献
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[目的]探讨干旱区盐渍化严重地区芦苇与盐分关系,揭示芦苇地下生物量垂直分布规律。[方法]通过野外调查、野外实地采样得到了较准确的芦苇种群地下生物量数据,利用统计学和生态学相结合的方法分析了芦苇地下生物量的垂直分布。通过试验测定了芦苇湿地有机碳和全氮的含量,求取了C/N比值,并分析了三者之间的相关性模型。[结果]芦苇种群地下总的生物量集中在10~40 cm土层,粗根在总的生物量中起明显的决定性作用。有机碳和全氮总体变化呈下降趋势,50 cm以下土壤有机碳和全氮变化趋势稳定。土壤有机碳与全氮含量呈显著正相关。[结论]为干旱区盐渍化地区芦苇地下生物量的获取提供了理论依据。 相似文献
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芦苇草DNA导入小麦抗盐性转化体的筛选 总被引:7,自引:0,他引:7
以鲁麦8号小麦为受体,开花授粉05h后导入芦苇草DNA10穗,113朵花。D0收获66粒,D1实收39个单株。从D2中选出16个变异株,出现比较明显变异性状的是无芒、粒色、株高、穗长、穗粒数、颖尖的锐、钝等,特别是变异后代的抗盐性。以上变异后代通过自然盐渍土、盐池、水培筛选,选育出了89D252213、89D311119等抗盐性新品系。从形态特征和性状上看,说明芦苇草DNA已进入到鲁麦8号受体细胞核内,并对受体基因组产生了影响,其后代得到充分表达。 相似文献
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