首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
浅析泸沽湖湿地存在问题及对策   总被引:1,自引:0,他引:1  
泸沽湖湿地是国家重要湿地,是特有物种波叶海菜花和裂腹鱼的生境和栖息地,也是雁鸭类水禽的越冬栖息地。据调查:泸沽湖湿地有水生植物23科30属44种,水生植被主要有12个群系,鱼类有1目4科12种,水鸟记录有7目11科50种,两栖类记录有1目3科6种,爬行类记录有1目2科3种,兽类2目2科5种。论文针对泸沽湖湿地保护管理中存在的问题,提出了保护管理对策。  相似文献   

2.
自2009年至2011年初,对福建兴化湾西岸越冬水鸟资源进行了调查,分析该区域越冬水鸟的种类、区系组成和水鸟对不同生境选择特征。兴化湾西岸记录到越冬水鸟共8目12科26属46种,区系地理分布以古北界种类为主,居留型以冬候鸟为主,国家二级重点保护野生动物有黑脸琵鹭1种,属于中日候鸟保护协定保护鸟类有32种,中澳候鸟保护协定保护鸟类有18种;黑嘴鸥、黑脸琵鹭和反嘴鹬的单个物种种群数量达到国际重要湿地标准。因此,兴化湾西岸是迁徙鸟类非常重要的中转站。在7种生境类型中,水产养殖场与滩涂围堰养殖区的越冬水鸟物种数和种群数量是最大的,农田作业区最小。因此,兴化湾西岸越冬水鸟对水产养殖场和滩涂围堰养殖区的选择偏好性最大。  相似文献   

3.
地处川滇交界处的泸沽湖自然保护区是中国西南地区重要的候鸟越冬栖息地和国内著名的旅游风景区。相关调查表明,虽然保护区内越冬水鸟的种群数量在近几年有所增加,但相比历史记录而言物种丰富度却有所下降,这可能与保护区旅游业的开发导致湖滨浅水沼泽湿地丧失,食物可利用度下降有关。因此,在保护区建立候鸟觅食栖息地,对于丰富湿地生物多样性,保障候鸟食物安全及其栖息地保护起到积极的作用。  相似文献   

4.
分3时段,设立4个观察点对纳帕海越冬水鸟种类和数量进行观察记录,共记录到鸟类6目11科49种,其中冬候鸟40种.并对水鸟的群落组成、保护鸟类、种群变动、生境变化等进行了分析讨论.  相似文献   

5.
漳江口红树林保护区越冬水鸟的年际变化   总被引:1,自引:0,他引:1  
通过对2009年至2014年连续6年的12月对漳江口红树林国家级自然保护区的越冬水鸟进行的调查,结果表明:该保护区共记录到越冬水鸟6目11科39种,主要类群为鸻鹬类、鹭类、鸭类和鸥类。保护区的越冬水鸟物种数量年际变化不大,在26~32种间波动,其中22种记录于所有年份;而水鸟数量年际间有比较大的波动,最少为1204只,最多达到5399只,近年来水鸟数量有下降的趋势。结合保护区现状提出保护对策和建议。  相似文献   

6.
作为云南省鸟类同步调查的一部分,为了掌握滇池越冬水鸟相关情况,根据《云南省鸟类同步调查实施细则》,围绕滇池选定24个观察点,分别于2015年1月11日和2016年1月14日分组同时对各观察点进行观察和统计。调查人员分4个组,每组调查6个点,1天之内完成。结果共记录到滇池水鸟32种,隶属于6目8科。对滇池越冬水鸟的种类组成、空间分布、栖息地现状及受干扰和威胁情况进行分析,并就滇池水鸟种类与数量在历次调查中的增减以及水鸟空间分布的影响因素进行了讨论,提出进一步恢复湿地,减少人为活动与捕鸟行为等保护建议。  相似文献   

7.
2003年3月5~13日、10月2~7日、11月9~25日,我们组织霞浦县、福安市、蕉城区有关人员,对三都湾滩涂湿地进行了较为全面的湿地与水禽资源调查。调查表明:三都湾是中国乃至世界罕见的天然良港,湾内滩涂湿地生物多样性丰富,特别是湿地水禽种类繁多,数量丰富,共发现鸟类12目20科53种,计有31 207只,是福建省鸟类资源的重要分布区,是各类水禽的理想栖息地、越冬地和迁徙地。但同时亦存在过度开发、盲目围垦等破坏水禽栖息地的现象,天然滩涂湿地现存面积仅为原来的1/3。为此,申报国际重要湿地,建立国家级湿地保护区示范区建设等保护和恢复三都湾湿地工作已是刻不容缓、迫在眉睫。  相似文献   

8.
根据湖北省湿地资源和越冬水鸟的分布特点,湖北省野生动植物保护总站选定在湖北龙感湖国家级自然保护区、沉湖国际重要湿地、网湖湿地自然保护区范围内开展越冬水鸟同步调查试点工作。本次调查的对象以《全国水鸟越冬期、迁徙期同步调查技术规程》确定的鹳、雁、鸭、鹤、鸻等水禽为主,采用直接计数法记录鸟类的种类和数量,并对鸟类栖息地地貌类型、水域面积及鸟类生存受干扰、受威胁因素进行调查。据初步统计,在试点范围内共观测到50多种水鸟,共计9万多只。目前,野外调查试点工作已圆满结束,下一步将组织专人对调查数据进行统计、分析,撰写试点调查报告,提出完善同步调查的建议和措施,为全国同步调查做好准备。——摘自湖北林业网  相似文献   

9.
分3时段,设立4个观察点对纳帕海越冬水鸟种类和数量进行观察记录,共记录到鸟类6目11科49种,其中冬候鸟40种.并对水鸟的群落组成、保护鸟类、种群变动、生境变化等进行了分析讨论.  相似文献   

10.
黄河三角洲是东北亚内陆和环西太平洋地区鸟类迁徙路线上重要的停歇地、越冬地和繁殖地,有水库、近海滩涂、芦苇沼泽、河流、盐池、渔塘等多种湿地生态类型,水鸟资源丰富。作者在2009年,以每月一次的调查频度,对黄河三角洲地区水鸟资源进行调查,共调查水鸟种类计数97种,数量总计数334046,其中湿地依赖鸟种种类计数6种,湿地依赖鸟种数量计数44种,受胁水鸟种类计数10种,受胁水鸟数量计数21432只。在调查数据的基础上,作者对水鸟年度动态变化作了分析,研究水鸟的动态变化规律。  相似文献   

11.

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.  相似文献   

12.

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.  相似文献   

13.

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.  相似文献   

14.

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.  相似文献   

15.
本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。  相似文献   

16.
17.

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.  相似文献   

18.

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.  相似文献   

19.
In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.  相似文献   

20.
The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha−1 target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha−1. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1); (2) Lolium perenne L. var. Tove (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m2, with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号