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 15 毫秒
1.
Ecological networks (ENs) of indigenous vegetation among commercial forestry plantations have been implemented to offset the negative effects of the alien plantation trees on local biodiversity. However, it is not known whether these ENs are equivalent to protected areas (PAs) in terms of their grassland biodiversity. To address this knowledge gap, we investigated how well grassland plant species richness and composition in an EN corresponds to similar habitats in an adjacent PA. This took place in grasslands on the east coast of South Africa, and was done at four paired sites using ten replicates at each of the eight sites. Pairwise comparisons (EN vs. PA) of plant species composition yielded statistically smaller differences than comparisons between different pairs of sites within either the EN or PA, illustrating considerable turnover of species whether or not they were in an EN or PA. Overall, there were fewer plant species in the EN for three of the four pairs of sites. Nevertheless, plant species composition was similar in each pair of sites. The grassland EN was also characterized by greater maximum vegetation height and less green vegetation cover. When differences between the EN and a PA were viewed against the natural variation of abiotic and biotic conditions across the landscape, they were small. We conclude that ENs of natural habitat contribute substantially to biodiversity conservation in transformed, commercially-productive landscapes, are almost as good as PAs for maintaining grassland plant diversity.  相似文献   

2.
This study investigated whether the fish communities inhabiting shallow non‐vegetated habitats in two divergent bays in a subtropical World Heritage Site estuarine system differed according to wet (spring–summer) and dry (autumn–winter) seasons or polyhaline and mesohaline zones, within the broader objective of facilitating spatio‐temporal management. Species richness (total of 74 taxa; total length, LT = 11–552 mm) and abundance (51 109 individuals) were mostly greater in the wet than dry season and in polyhaline than mesohaline areas. There was a major effect of rainfall on recruitment, particularly among transient fishes, which could be the result of enhanced survival of young via greater productivity (food resources) and protection from predators (via turbidity reducing visual cues). Salinity had strong interactive effects with rainfall and temperature in one bay, with greater species richness and overall abundances as well as large abundances of four key species [Anchoa januaria and Atherinella brasiliensis (pelagic residents), Cetengraulis edentulus (pelagic transient) and Diapterus rhombeus (demersal transient)] during the wet season in polyhaline areas; possibly reflecting a biodiversity hotspot that might be affected by distance to the estuary mouth and convergence hydrology. Regionally, the results support enforcing spatio‐temporal restrictions to minimize anthropogenic activities within statutory (but not always enforced) protected areas. Globally, the data reiterate the need to identify and understand biotic and abiotic effects on estuarine ichthyofaunal distributions and abundances as a precursor to their management.  相似文献   

3.
保护地的声景具有重要价值。声景感知是衡量保护地声景质量的有效工具之一。声景感知受到声景环境、声源构成、主导音等要素影响,也会对人们环境感知的可接受度、情绪等方面产生影响。已有对城市和乡村环境中主导音、听觉对视觉及情绪影响等方面的研究,但对保护地中声景感知及影响感知的要素研究较为缺乏。以武陵源世界遗产地的声景为对象,通过听音实验,相关性分析、对比分析得出武陵源声景的总体特点。可知武陵源声环境中导游喇叭和谈话的声音是感知频率高且接受度最低的声源,因而在保护管理中应予以重视和控制。武陵源世界遗产地内乡村环境中的鸟鸣、流水等自然声源的可接受度要高于武陵源中纯自然环境中的同等声源的可接受度。在低噪声环境下,高感知频率的声源与主导音不一致,即被感知频率高的声源不一定是主导音。并通过相关性分析,得出声景与情绪感知与性格之间存在相关性,且不同声景环境中的自然声源均能使性格“内向安静”和“易焦虑的人”感到“放松”“舒适”和“多样丰富”。最后,基于上述结论,提出了对武陵源声景价值认知的策略和保护管理的建议。  相似文献   

4.
At present, there is very limited information on the ecology, distribution, and structure of Cambodia’s tree species to warrant suitable conservation measures. The aim of this study was to assess various methods of analysis of aerial imagery for characterization of the forest mensuration variables (i.e., tree height and crown width) of selected tree species found in the forested region around the temples of Angkor Thom, Cambodia. Object-based image analysis (OBIA) was used (using multiresolution segmentation) to delineate individual tree crowns from very-high-resolution (VHR) aerial imagery and light detection and ranging (LiDAR) data. Crown width and tree height values that were extracted using multiresolution segmentation showed a high level of congruence with field-measured values of the trees (Spearman’s rho 0.782 and 0.589, respectively). Individual tree crowns that were delineated from aerial imagery using multiresolution segmentation had a high level of segmentation accuracy (69.22%), whereas tree crowns delineated using watershed segmentation underestimated the field-measured tree crown widths. Both spectral angle mapper (SAM) and maximum likelihood (ML) classifications were applied to the aerial imagery for mapping of selected tree species. The latter was found to be more suitable for tree species classification. Individual tree species were identified with high accuracy. Inclusion of textural information further improved species identification, albeit marginally. Our findings suggest that VHR aerial imagery, in conjunction with OBIA-based segmentation methods (such as multiresolution segmentation) and supervised classification techniques are useful for tree species mapping and for studies of the forest mensuration variables.  相似文献   

5.
该研究在申遗文本和大量文献资料的基础上,以峨眉山世界遗产地原生植物及植被群落为研究对象,从物种多样性、物种组成、植物区系、植被类型及垂直分布格局等方面,分析论证了峨眉山世界遗产地植物多样性的全球突出普遍价值,并简要概述了当前峨眉山世界遗产地植物受威胁状况以及在保护与发展中出现的问题。结果表明:(1)峨眉山世界遗产地目前拥有高等植物242科3 200种以上,特有植物、孑遗植物种类丰富。(2)与中国其他湿润性亚热带山地森林垂直带谱相比,峨眉山亚热带森林植被类型完整,常绿阔叶林东部类型在山地垂直带谱中占据显著地位,海拔上限最高,跨度最大,具有典型的亚热带常绿阔叶林东部亚区森林群落特点。(3)植物区系复杂,既有热带、亚热带和温带植物区系成份,又有中国—日本与中国—喜马拉雅植物区系分布。(4)受人为活动(旅游发展、基础设施建设等)和自然扰动(气候变暖、地质灾害等)影响,峨眉山世界遗产地植物多样性下降明显,珍稀濒危植物受威胁程度增加,典型群落面积退化,稳定性降低。建议在划定珍稀植物保护区,对植物栖息地进行专门保护的基础上,开展植物多样性、环境因子、人为活动动态监测,预见性地保护其突出普遍价值,实现世界遗产地的可持续发展。  相似文献   

6.
近30年来,九寨沟在推进旅游可持续发展方面进行了长期有益的探索和实践,其经验获得国内外的普遍认同。与此同时,日益增长的游客规模对生态环境和生物多样性保护的威胁,逐渐成为旅游可持续发展面临的最大挑战。生物多样性保护是九寨沟的使命之一,在游客容量测算中应予以充分考虑,这在游客规模日益增加的背景下尤显重要。但是目前传统的游客容量测算中却没有涉及生物多样性容量,而且由于生物多样性监测数据和相关知识不充分,生物多样性容量也难以进行测算。因此,需要在下一步有针对性地积累生物多样性监测数据,将其结果纳入游客容量测算中,并在此基础上探索执行以监测为基础的游客容量适应性管理机制。  相似文献   

7.
8.
杜爽  韩锋  马蕊 《生物信息学》2019,26(12):85-90
自然圣境(sacred natural sites,简称SNS)是自然保护地体系的重要构成,也是典型的文化景观。它们作为人与自然互动的历史记录,所蕴藏的文化价值是其赖以存在的根基。从单纯的自然保护到融合文化价值的整体性保护,反观国外SNS保护工作的方向性转变,有助于在全球发展主义时代背景下从“术”的层面重新审视中国SNS保护工作中面临的诸多挑战,对于推进中国生态文明建设具有重大意义。从世界遗产角度,在阐述SNS概念的基础上,全面梳理不同国际组织机构参与下的SNS保护实践进展;总结目前在其保护中涉及的景观方法和生物文化多样性方法等主流保护方法;最后指出在国家公园体制背景下,充分开展本土SNS基础调研,完善相关规划并确立保护条例,在遗产地可持续发展的基础上协调SNS中的人际间及人与其他物种的公平关系是中国SNS保护成功的关键。  相似文献   

9.
刘赟  侯秀发  周江 《生态学杂志》2013,32(7):1850-1856
通过对贵州省中国南方喀斯特第二批世界自然遗产提名预选地施秉县的鱼类物种组成进行调查,共采集到鱼类46种,隶属于7目15科39属,其中鲤形目(Cypriniformes) 有28种,占本次调查的61%.在物种组成上,土著鱼类是该区域河流的主体,有40种,占87%;外来鱼类有6种,约占13%.其中外来入侵物种有食蚊鱼(Gambusia affinis);大银鱼(Protosalanx hyalocroaniah属于人工放养;从人工养殖地逃逸到野外的鱼类有4种,分别为草鱼(Ctenopryngodon idellus)、鲢(Hypophthalmichthys molitrix)、鳙(Aristichthys nobilis)和团头鲂(Megalobrama amblycephala).  相似文献   

10.
11.
为了解荔波世界自然遗产地翼手目动物的物种多样性和生存现状, 作者于2010年10月至2011年10月, 对中国南方喀斯特荔波世界自然遗产地区域内6个镇(乡)69个洞穴的翼手目动物进行了考察, 发现60个洞穴有翼手目动物栖息痕迹, 其中可以确定具体栖息物种的洞穴有37个。本次调查观察记录到翼手目动物10万余只, 隶属5科15种, 结合文献记载及贵州师范大学动物标本室保存的翼手目动物标本, 确认该地区共有翼手目动物7科24种。11种翼手目动物在荔波世界自然遗产地为首次记录, 其中狭耳鼠耳蝠(Myotis blythii)、果树蹄蝠(Hipposideros pomona)2种为贵州省翼手目新记录。该地区一些洞穴已被开发为旅游景点, 严重影响了洞穴内翼手目动物的生存, 翼手目动物保护状况令人担忧, 建议对翼手目动物栖息的洞穴采取必要的保护措施。  相似文献   

12.
Emotional and behavioral problems have been considered an indicative of mental disorder in children. Mental health problems affect 10–20% of children and adolescents living in low-income and middle-income countries. Evidence suggests that disruptions in the biological rhythm may be a primary cause of emotional and behavioral changes, which affects several psychological functions and moods. Thus, this study aimed at verifying the association between biological rhythm and emotional and behavioral problems in schoolchildren living in Southern Brazil. This is a cross-sectional study with a school-based sample conducted between August 2015 and November 2016. The presence of emotional and behavioral problems in children was verified by the Strengths and Difficulties Questionnaire (SDQ), parents’ version. This is a 25-item assessment questionnaire used to screen mental health problems in children and adolescents (from 4 to 17 years of age) in the last 6 months. The Biological Rhythm Interview of Assessment in Neuropsychiatry-Kids (BRIAN-K) was used to measure the degree of biological rhythm disruption. The BRIAN-K consists of 20 items; from among these, 17 items are added to generate a quantitative measure, with greater scores indicating more biological rhythm disruption. The final score can also be divided into four subscales: sleep, social rhythm, eating pattern and overall activities. A total of 609 children responded to the assessment instruments. With regard to parents or primary caregiver, 596 completed the assessment and 13 (2%) were not located or refused to participate in the study. Thus, 596 dyads were included in the analysis. Children with emotional and behavioral problems presented higher scores in all domains of BRIAN-K: sleep, social, activity, eating pattern and total score (p < 0.001). The following variables remained associated with emotional and behavioral problems after adjusted analysis: BRIAN-K total score (p < 0.001) and all subscales sleep (p < 0.001), social (p < 0.001), activity (p < 0.001) and eating pattern (p < 0.001). Children with emotional and behavioral problems presented higher biological rhythm disruption when compared with children without emotional and behavioral problems. Our study emphasizes the importance of biological rhythm and its influence on emotional and behavioral problems in schoolchildren. Early detection of any biological rhythm disruption may enhance further assessment of any eventual emotional and behavioral problem and even a psychopathology.  相似文献   

13.
世界文化景观遗产的申报,是近年来国内越来越关注的话题,作为中国第一个成功以文化景观列入世界遗产名录的案例,五台山的申报过程为中国的文化景观遗产申报与研究提供了很多线索,尤其在突出普遍价值的认识及其保护管理方面,更是积累了一定的经验,同时也引发了新的思考。经过申报前后对遗产价值标准的对比研究及对保护管理的重新思考,认识到文化景观必须将自然、文化作为一个整体加以认知和保护,尤其要研究人与自然之间的作用机制,重视其中活态遗产的保护和展示。  相似文献   

14.
One hundred Selenichnites rossendalensis (excavations), sometimes with associated trackways, have been found at Joggins Fossil Cliffs (Nova Scotia, Canada; Pennsylvanian). The majority of the Selenichnites found in this study contain only one lunate cast and some are distinguished by linear ridges that project behind a single lunate cast. A detailed investigation of the morphology and orientation of these Selenichnites—attributable to xiphosurans, relatives of modern horseshoe crabs (Limulus polyphemus)—yields an understanding of xiphosuran digging behavior. Statistical analysis of 96 lunate casts from two populations of Selenichnites separated by several hundred thousand years shows, with 99% confidence, that the prosomas (heads) of the younger population are smaller. Further study of the wealth of Selenichnites at Joggins will be useful to determine which factors control xiphosuran body-size changes and the timescale on which those changes can be seen manifest in a population. The smallest known Selenichnites (7 mm wide) is also reported.  相似文献   

15.
16.
We investigated the polymorphism of human leukocyte antigens (HLA) and Duffy erythrocyte antigens in chronic kidney disease (CKD) patients in southern Brazil. One hundred and eighty-three CKD patients, over 18 years old, on hemodialysis, were included. HLA-A, -B and -DRB1 typing was performed using the LABType®SSO (One Lambda, Inc.). Duffy phenotypes were determined by gel column agglutination using anti-Fya and anti-Fyb monoclonal anti-sera. The patients'' predominant ages ranged between 51 and 70 years (43%) and the predominant gender, ethnic group and dialysis period were, respectively, male (62%), white (62%) and 1–3 years (40%). The highest and lowest frequencies of Duffy phenotypes were Fy(a+b+) and Fy(a−b−), respectively. Nineteen HLA-A, 30 HLA-B and 13 HLA-DRB1 allele groups were identified. The most frequent HLA allele groups were HLA-A*01, -A*02, -A*03, -A*11, -A*24; HLA-B*07, -B*15, -B*35, -B*44, -B*51; HLA-DRB1*03, -DRB1*04, -DRB1*07, -DRB1*11 and -DRB1*13. Statistically significant differences were observed in the Duffy and HLA polymorphisms compared between CKD patients and healthy subjects. The Fy(a+b−) phenotype (p<0.0001, OR = 2.56, 95% CI = 1.60–4.07) was the most frequent in the patients (p<0.05), and the Fy(a+b+) phenotype (p = 0.0039, OR = 1.71, 95% CI = 1.18–2.51) was the most frequent in the healthy subjects in the same region of Paraná state (p<0.05). Regarding HLA, the HLA-B*42, -B*45, -B*51 and -DRB1*03 allele groups were the most frequent in the patients (p<0.05), and the HLA-B*44 allele group was the most frequent in the healthy subjects in the same region of Brazil (p<0.05). The polymorphism of these two markers among CKD patients in southern Brazil and healthy subjects of other studies, suggests that these markers might be involved with CKD development. Further studies should be undertaken to analyze the markers'' influence on CKD and the long-term results from kidney transplantation.  相似文献   

17.
Protein-RNA docking is hampered by the high flexibility of RNA, and particularly single-stranded RNA (ssRNA). Yet, ssRNA regions typically carry the specificity of protein recognition. The lack of methodology for modeling such regions limits the accuracy of current protein-RNA docking methods. We developed a fragment-based approach to model protein-bound ssRNA, based on the structure of the protein and the sequence of the RNA, without any prior knowledge of the RNA binding site or the RNA structure. The conformational diversity of each fragment is sampled by an exhaustive RNA fragment library that was created from all the existing experimental structures of protein-ssRNA complexes. A systematic and detailed analysis of fragment-based ssRNA docking was performed which constitutes a proof-of-principle for the fragment-based approach. The method was tested on two 8-homo-nucleotide ssRNA-protein complexes and was able to identify the binding site on the protein within 10 Å. Moreover, a structure of each bound ssRNA could be generated in close agreement with the crystal structure with a mean deviation of ~1.5 Å except for a terminal nucleotide. This is the first time a bound ssRNA could be modeled from sequence with high precision.  相似文献   

18.
The influence of topographic and temporal variables on cetacean distribution at a fine-scale is still poorly understood. To study the spatial and temporal distribution of harbour porpoise Phocoena phocoena and the poorly known Risso’s dolphin Grampus griseus we carried out land-based observations from Bardsey Island (Wales, UK) in summer (2001–2007). Using Kernel analysis and Generalized Additive Models it was shown that porpoises and Risso’s appeared to be linked to topographic and dynamic cyclic variables with both species using different core areas (dolphins to the West and porpoises to the East off Bardsey). Depth, slope and aspect and a low variation in current speed (for Risso’s) were important in explaining the patchy distributions for both species. The prime temporal conditions in these shallow coastal systems were related to the tidal cycle (Low Water Slack and the flood phase), lunar cycle (a few days following the neap tidal phase), diel cycle (afternoons) and seasonal cycle (peaking in August) but differed between species on a temporary but predictable basis. The measure of tidal stratification was shown to be important. Coastal waters generally show a stronger stratification particularly during neap tides upon which the phytoplankton biomass at the surface rises reaching its maximum about 2–3 days after neap tide. It appeared that porpoises occurred in those areas where stratification is maximised and Risso’s preferred more mixed waters. This fine-scale study provided a temporal insight into spatial distribution of two species that single studies conducted over broader scales (tens or hundreds of kilometers) do not achieve. Understanding which topographic and cyclic variables drive the patchy distribution of porpoises and Risso’s in a Headland/Island system may form the initial basis for identifying potentially critical habitats for these species.  相似文献   

19.
Smallpox and the ABO system in Southern Brazil   总被引:1,自引:0,他引:1  
  相似文献   

20.
武陵源世界自然遗产地地处我国生物多样性关键区域之一的武陵山脉,保护优先级别高,但遗产地自建立以来一直未开展系统的野生动植物资源本底调查,这不利于遗产地的有效管理。为了掌握遗产地兽类和鸟类资源现状,促进生物多样性的科学保护,2016年1月至2017年7月,我们利用36台红外相机,在武陵源世界自然遗产地共布设了107 个位点,每个位点工作4个月左右。结果表明:共获得野生兽类独立有效照片607张,隶属于4目8科的14 种;物种相对丰富度指数排前7位的兽类依次是猕猴 (Macaca mulatta)、红腿长吻松鼠 (Dremomys pyrrhomerus)、猪獾 (Arctonyx collaris)、小麂 (Muntiacus reevesi)、鼬獾 (Melogale moschata)、花面狸 (Paguma larvata taivana)、毛冠鹿 (Elaphodus cephalophus)。共获得鸟类独立有效照片907张,隶属于5目10科的37 种;物种相对丰富度指数排前7位的鸟类依次是紫啸鸫 (Myophonus caeruleus)、红腹锦鸡 (Chrysolophus pictus)、虎斑地鸫 (Zoothera dauma)、红嘴蓝鹊 (Urocissa erythrorhyncha)、灰翅鸫 (Turdus boulboul)、黑领噪鹛 (Garrulax pectoralis)、松鸦 (Garrulus glandarius)。白颈长尾雉 (Syrmaticus ellioti) 为国家一级重点保护野生动物;红腹锦鸡、红腹角雉 (Tragopan temminckii)、勺鸡 (Pucrasia macrolopha)、凤头鹰 (Accipiter trivirgatus)、猕猴为国家二级重点保护野生动物。猕猴、红腹锦鸡、紫啸鸫和红腿长吻松鼠为日行性动物,猪獾为夜行性动物。红腹锦鸡、紫啸鸫和红腿长吻松鼠在12:00~14:00活动频率下降,原因可能是这几种动物通过降低活动频率来躲避中午的高温和减少能量消耗。  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