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1.
Method for evaluating the degrees of land use sustainability of mountainous county and its application in Yunnan Province,China 总被引：4，自引：1，他引：3
The evaluation of sustainable land use is the key issue in the field of studying the sustainable land utilization. In general analysis, the sustainable land use is evaluated respectively from its ecological sustainability, economic sustainability and social sustainability in China and other countries in recent years. Although this evaluation is an important work, it seems insufficient and hard to comprehensively reflect the whole degree of land use sustainability. Thus, to make up this deficiency, this paper brings forward the evaluation indexes, which make it possible to quantitatively reflect the whole degree of land use sustainability, namely, the concept of ＂degrees of overall land use sustainability＂ （Dos）, and research and measurement development of the method of and calculation in Dos. Taking the evaluation of the degree of land use sustainability in county regions of Yunnan Province as the actual example for analysis, results are basically as follows：
1） The degree of land use sustainability （Dos） is the ration index to organically and systematically integrate the degree of ecological friendliness （DeF）, the degree of economic viability （Dev） and the degree of social acceptability （Dsa）, able to comprehensively reflect the whole sustainability degree of regional land use
2） Based on the value of Dos, the grading system and standard for the sustainability of land use may be established and totally divided into five grades, namely, the high-degree sustainability, middle-degree sustainability, low-degree sustainability, conditional sustainability and non-sustainability. Meanwhile, the standard for distinguishing sustainability grades has also been confirmed so as to determine the nature of sustainability degrees in different grades. This makes the possibility for the combination of nature determination with ration in research result and provides with the scientific guideline and decision-making gist for better implementation of sustainable land use strategy.
3） The pract 相似文献
1） The degree of land use sustainability （Dos） is the ration index to organically and systematically integrate the degree of ecological friendliness （DeF）, the degree of economic viability （Dev） and the degree of social acceptability （Dsa）, able to comprehensively reflect the whole sustainability degree of regional land use
2） Based on the value of Dos, the grading system and standard for the sustainability of land use may be established and totally divided into five grades, namely, the high-degree sustainability, middle-degree sustainability, low-degree sustainability, conditional sustainability and non-sustainability. Meanwhile, the standard for distinguishing sustainability grades has also been confirmed so as to determine the nature of sustainability degrees in different grades. This makes the possibility for the combination of nature determination with ration in research result and provides with the scientific guideline and decision-making gist for better implementation of sustainable land use strategy.
3） The pract 相似文献
2.
Viability theory for an ecosystem approach to fisheries 总被引：1，自引：1，他引：1
3.
《Marine Policy》2017
This article presents the first bottom-up analysis of the proportion of global marine fisheries subsidies to small-scale fisheries (SSF). Using existing data, the reported national subsidy amounts are split into the fraction that goes to small- and large-scale fishing sectors. Results reveal a major imbalance in subsidy distribution, with SSF receiving only about 16% of the total global fisheries subsidy amount of $35 billion in 2009. To bring this into perspective, a person engaged in large-scale fishing received around 4 times the amount of subsidies received by their SSF counterparts. Furthermore, almost 90% of capacity-enhancing subsidies, which are known to exacerbate overfishing go to large-scale fisheries, thus increasing the unfair competitive advantage that large-scale fisheries already have. The developmental, economic and social consequences of this inequity are huge and impair the economic viability of the already vulnerable small-scale fishing sector. Conclusions indicate that taxpayers' money should be used to support sustainable fishing practices and in turn ocean conservation, and not to foster the degradation of marine ecosystems, often a result of capacity-enhancing subsidies. Reducing capacity-enhancing subsidies will have minimal negative effects on SSF communities since they receive very little of these subsidies to begin with. Instead, it will help correct the existing inequality, enhance SSF economic viability, and promote global fisheries sustainability. 相似文献
4.
以不同铜离子添加量(0, 10, 25, 40, 55 和110 mg/kg)的饲料喂养斑节对虾(Penaeus monodon)8 周,测定对虾的血细胞总数(THC), 并应用流式细胞术测定血细胞中含颗粒细胞(小颗粒细胞和大颗粒细胞)的比例、血细胞凋亡率、活性氧(ROS)含量和酯酶活性。结果显示, 当铜添加量为10～55 mg/kg 时, 与对照组相比, 对虾的THC、血细胞凋亡率、ROS 含量和酯酶活性均没有显著的变化(P>0.05); 铜添加量为25～110 mg/kg 时, 含颗粒细胞的比例显著提高(P<0.05); 铜添加量为110 mg/kg 时, ROS 含量显著高于其他组(P<0.05), 血细胞凋亡率高于25 和55 mg/kg 组(P<0.05), THC 低于55 mg/kg 组(P<0.05), 酯酶活性低于25mg/kg 组(P<0.05)。这些结果表明, 适宜的饲料铜含量有利于两类颗粒细胞的生成; 铜添加过量(110 mg/kg)会诱导血细胞ROS 的产生, 造成氧化损伤, 从而导致凋亡率上升和THC 下降。综上所述, 在本实验日粮条件下, 针对斑节对虾的血细胞功能, 其饲料中铜适宜添加含量范围为25～55mg/kg。 相似文献
5.
包埋脱水法冷冻保存裙带菜配子体克隆的研究 总被引：6，自引：0，他引：6
将裙带菜配子体克隆包埋在含3%褐藻酸钙的胶球中,研究了预培养中的蔗糖浓度和培养时间,脱水过程中的脱水速率和胶球含水量以及化冻速度对配子体克隆的存活率和发育能力的影响,结果表明含裙带菜配子体克隆的胶球在0.3 mol/dm3的蔗糖培养基中培养9 h可以获得较高的存活率;胶球最适平均脱水速率为含水量的5%每小时,最适含水量为25%;较快的化冻速度可以显著提高配子体克隆的存活率,在优化条件下存活率可高达66%;经过冷冻保存的裙带菜配子体克隆在适合发育的条件下能够正常形成孢子体. 相似文献
6.
锯缘青蟹精子低温冷藏及精子活力的染色法评价 总被引：11，自引：0，他引：11
采用天然海水配制的台盼蓝染色液和曙约B染色液对低温冷冻的锯缘青蟹精子的活力进行评价研究。结果表明，用这两种染色液染色死活精子呈现出明显不同的特征，进而以无锡离子人工海水（Ca^2 -FSW)为冷冻基础液，分别用10％（V／V）甘油、5％（V／V）二甲亚砜（DMSO）作冷冻剂，进行了4℃液态低温保存的精子实验，对照组不加冷冻剂，以Ca^2 -FSW等量代替，同时采用染色法对保存精子活力进行评价，结果显示台盼蓝不适宜于评价甘油组精子的活力，但却能评价对照组和二甲亚砜组。在24h内，二甲亚砜组精子的存活率达58．7％，而对照组仅为30．2％。可见，染色法可以作为低温冷冻保存的锯缘青蟹精子活力评价的一种有效方法。 相似文献
7.
8.
利用筛选出的精子遗传失活法和卵染色体加倍法,批量诱导出第二极体抑制型栉孔扇贝雌核发育二倍体个体,观测了幼体不同发育时期的成活率、发育速度和个体大小等生物学特性。结果发现,雌核发育二倍体的卵裂率、胚胎畸形率、D形幼虫发生率、孵化后3,6,9,12,15,18 d的成活率均显著低于对照组,表明栉孔扇贝基因组中可能存在大量有害隐性基因,雌核发育个体中有害隐性基因的纯合导致了成活率的显著下降。在发育速度方面,D形幼虫期之前,雌核发育二倍体个体明显低于对照组个体;壳顶期后则相反,雌核发育二倍体个体高于对照组个体。在个体大小方面,雌核发育二倍体个体在孵化后3 d前,壳长和壳高均小于对照组个体;孵化3 d后,壳长和壳高逐渐大于对照组个体。这一结果显示随着致死隐性基因因纯合而被自然排除,雌核发育二倍体的生长性状逐渐优越于正常个体,通过将这些雌核发育二倍体个体培养至成体,则可望培育出栉孔扇贝的优良品系。 相似文献
9.
A. Ouled Belgacem M. Neffati V.P. Papanastasis M. Chaieb 《Journal of Arid Environments》2006,65(4):682-687
Native grass species are being considered in the restoration of degraded rangelands in Tunisia due to the failure of introduced species to adapt to the ecological constraints of the region. The objective of this study was to determine the effects of seed age and seedling depth on emergence and seedling vigor of Stipa lagascae, a perennial bunchgrass that is native to the region and shows promise as a species for restoration purposes. Total emergence percentage of seedlings and the coefficient of rate of emergence (CRE), the seedling vigour as well as above and below-ground biomass were measured. Younger seeds had higher emergence rates than older seeds. However, seed age did not affect variables associated with seedling vigour. Seeding depth significantly affected all parameters tested. A seeding depth of 4–6 cm was found to be optimal. 相似文献
10.
This paper presents data on the germination traits of five perennials (Allium polyrrhizum, Agropyron cristatum, Arenaria meyeri, Artemisia frigida and Artemisia santolinifolia) widespread in the mountain steppes of southern Mongolia. Germination and seed viability were assessed at three alternate temperatures (8/4 °C, 20/10 °C, 32/20 °C), three levels of osmotic stress (deionized water; −0.5 MPa, −1 MPa Mannitol solution), and under conditions of alternate light/darkness versus complete darkness. The results of a factorial ANOVA with treatments and species as main effects showed that all five species germinated best at higher temperatures, with only Agropyron cristatum showing some seed mortality. Osmotic stress reduced seed viability and total germination in all five species. Darkness had no influence on viability, but positively affected seed germination of Allium polyrrhizum and Agropyron cristatum. We therefore conclude that, in the field, germination of all five species is mainly controlled by ambient temperatures and water availability, both of which drop towards the end of summer when dispersal takes place and effectively delay seedling recruitment until the next vegetation period. 相似文献