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1.
京沪高速铁路天津、沧州地区存在不同程度的地表沉降。以京沪高速铁路天津地区沿线的水准观测数据为研究对象,采用反距离加权法、径向基函数法与泛克里格插值法对研究对象进行了空间插值分析,通过精度评定与结果检验发现泛克里格方法能够较好地反映地表趋势面,可以作为研究该区域地表沉降的一种方法。  相似文献   

2.
体感温度指数综合考虑了温度和湿度对人体的影响,可有效表征人体舒适度,对于研究城市热岛效应对人体健康的影响具有重要意义。基于2017年7月10日的Landsat 8卫星影像运用单通道算法反演北京市的地表温度,结合NDVI、MNDWI、海拔及水汽含量等环境因子,构建随机森林模型估算近地表气温;基于同一天的MODIS水汽产品提取大气可降水量,运用逐步回归方法建立近地表水汽含量与大气可降水量、地表温度及海拔之间的关系来估算近地表露点温度,在此基础上计算Humidex指数来表征北京市体感温度的空间分布。结果表明,模型估算的体感温度平均绝对误差(MAE)为1.40℃,均方根误差(RMSE)为1.71℃。北京市7月10日的体感温度范围为24~42℃,具有东南高西北低的分布特征。主城区和近郊区的体感温度显著高于远郊区,并向四周呈递减趋势;受空气湿度的影响,平谷南部、密云河谷一带、延怀盆地以及房山东南部等部分远郊地区的体感温度也比较高。就城市内部的体感温度而言,不同功能区的分布使得体感温度在相邻区域上存在空间差异性,东城区和西城区体感温度最高,平均值达到了39.79℃,丰台区、海淀区、石景山区和朝阳区的平均体感温度也达到了34.29℃。体感温度与气温在空间分布上具有一致性,但整体上高于气温,在主城区和各区中心区域,体感温度比气温高5℃以上。该研究尝试通过遥感手段反演北京地区体感温度指数,获取了北京市体感温度的详细空间分布信息,为城市人居环境和城市热岛效应研究提供了科学参考。  相似文献   

3.
Kriging插值法在植物物种地理分布空间格局研究中的应用   总被引:1,自引:0,他引:1  
孔红梅  韦琳林  刘国华 《生态环境》2010,19(5):1165-1169
Kriging插值法是一种定量化描述地理空间分布格局的方法,主要应用于空间采样以及相关的一些空间格局分析。而物种的地理空间分布是物种在自然及人类活动共同作用下的结果。物种分布的研究目前主要从气候的角度来探讨其与气候之间的关系,并取得了很好的结果,但是仅从气候考虑又有局限性,而且很难真实地反映出物种地理空间的分布格局。因此,将Kriging插值法引进到物种分布的研究中,并以我国广泛分布的物种——栓皮栎为例,探讨其可行性。结果表明:Kriging插值法能很好地拟合物种地理空间分布的实际情况,其误差程度较小。该研究的结果可为物种资源的开发利用和物种的引种栽培提供理论依据。  相似文献   

4.
全球变暖有很大的差异性,表现在昼夜增温速度和各个季节的温度增加的速率具有不一致性,夜间增温的速度要快于白天增温的速度,夜间气温的增温对植被变化的影响更为明显。文章利用34年逐月最高温、最低温以及降水量数据,用一元线性回归分析法、反距离权重插值以及二阶偏相关分析法,分析了西北地区白天和夜间气温的非对称时空变化和非对称增温趋势对植被动态的影响,结果表明:西北地区昼夜温度都呈现出上升的趋势,且上升趋势比较明显,白天增温的速度和夜间增温的速度呈现出不对称性,夜间温度升高的速率是白天温度升高速率的1.2倍,昼夜的温差呈现出减小的趋势;西北地区昼夜增温趋势存在不一致性,白天气温的增温速率在-0.02-0.11℃?a-1,夜间气温的增温速率在-0.06-0.2℃?a-1。tmax和tmin在绝大部分地区都呈现上升趋势,但在空间变化的区域上具有不对称性;西北地区植被生长对昼夜增温的响应具有明显的空间差异性,大部分地区的植被对昼夜增温表现为积极的响应,夜间增温对植被的影响要比白天增温对植被的影响是比较明显的;白天和夜间增温的不对称性影响着不同类型的植被,白天气温的升高有利于针叶林植被、草地和阔叶林植被的生长,而夜间气温的升高对灌丛和荒漠植被的生长有积极的影响。  相似文献   

5.
植被覆盖层对微波遥感反演地表土壤水分产生重要影响。以河北省景县为研究区,基于Sentinel-1 SAR遥感数据和Sentinel-2光学遥感数据,采用改进水云模型和Oh模型的组合方法,对植被覆盖地表土壤水分进行定量反演研究。结果表明:在Sentinel-1 VV极化条件下,改进水云模型和Oh模型的组合方法具有较高的反演精度,决定系数(R~2)为0.653 0,均方根误差(RMSE)为0.040 1 cm~3·cm~(-3),平均绝对误差(MAE)为0.032 7 cm~3·cm~(-3),这3项反演精度评价指标均优于VH极化。该方法在获取高空间分辨率和高精度的植被覆盖区农田土壤水分信息方面具有较高的应用价值。  相似文献   

6.
北京松山油松种群结构及空间分布格局   总被引:3,自引:0,他引:3  
研究了北京松山自然保护区天然油松(Pinus tabulaeformisr)林的树冠结构和个体胸径,通过Ripley's K函数探讨了油松种群不同层次个体(幼树、小树和大树)的空间分布及空间关系,并探讨了地形(海拔高度、坡度)对油松种群空间分布的影响.结果表明,油松种群的胸径分布呈双峰型,应用Weibull函数拟合效果较好;树冠分布呈倒J型;胸径与冠幅存在显著的指数关系.油松种群呈聚集分布,但随高度增Jm(幼树→树→大树)聚集强度逐渐减弱,枯立木在样地内呈随机分布.枯立木与油松大树在1 m、5 m和13~18 m距离为显著正相关,幼树与小树在2~4 m和6~18 m距离呈显著正相关.海拔高度与油松种群呈正相关,坡度与幼树分布呈正相关,与小树和大树分布呈负相关.图5表2参24  相似文献   

7.
三江平原地区农田土壤中几种重金属空间分布状况   总被引:4,自引:0,他引:4  
以三江平原地区农田土壤为研究对象,基于网格法取样,运用经典统计学和地统计学方法对研究区域内土壤重金属As、Cr、Cu、Pb和Zn的空间分布特征进行研究。结果表明,三江平原地区5种土壤重金属具有较高的空间异质性,变异系数在30.67%~66.89%之间;As、Cr、Cu、Pb和Zn均具有较强的空间自相关性,空间自相关范围较广;As和Cr的块金值和基台值之比〔C0/(C0+C)〕25%,其空间变异主要由土壤母质、地形和气候等自然因素(结构性变异)引起,Cu、Pb和Zn的C0/(C0+C)为35.8%~43.2%,非结构性因素对Cu、Pb和Zn的影响较大;5种重金属元素的空间分布格局不同,土壤各重金属元素在小尺度范围内存在明显的空间变异,除Cu元素外,其他4种重金属元素在大尺度空间范围内均不具有明显的空间分布规律;采用普通克里格插值法得到三江平原地区表层土壤重金属的空间分布图,发现土壤重金属含量与土壤类型、土壤理化性质、土地利用方式以及矿山开采、农业机械化强度、农业灌溉关系密切。  相似文献   

8.
中国土壤碱解氮含量与影响因子的空间关系研究   总被引:4,自引:0,他引:4  
不同地区之间的地域差异,使以往针对土壤碱解氮与影响因子关系的研究存在着相互矛盾的结论。为比较不同环境条件下土壤碱解氮含量空间分异潜在主导因子的一致性与差异性,基于现有的GIS数据,采用地理探测器的研究方法,分别以全国及自然区划尺度为研究单位分析中国土壤碱解氮含量空间分异的潜在主导因子。结果表明,(1)从全国尺度上看,土地利用方式与气温及降水的共同作用主导了中国土壤碱解氮含量的空间分异过程。不同土地利用方式下土壤碱解氮含量的差异大致表现为林地(147 mg·kg~(-1))草地(113 mg·kg~(-1))耕地(103 mg·kg~(-1))水域(95 mg·kg~(-1))建设用地(92 mg·kg~(-1))未利用地(55 mg·kg~(-1))。在此基础上,气温与降水的变化进一步改变了地表的环境条件与植被状况,使得土壤碱解氮含量在大区尺度上发生更复杂的变化。(2)从自然区划尺度上看,影响土壤碱解氮含量空间分异的潜在主导因子存在一致性,但同时也存在差异。中国东部湿润季风区土壤碱解氮主要受气温影响。而在西部干旱区,降水以及坡度对碱解氮的作用相对较大。此外,在地形条件复杂的亚热带常绿阔叶林带、温带森林草原带及青藏高原区,海拔高度的变化对土壤碱解氮含量的影响最显著。因此,该研究认为影响土壤碱解氮含量空间分异的潜在主导因子会因其所处环境条件的不同而存在明显差异,但这些主导因子在一定程度上均能够有效反映各自然区划带的基本环境特征。  相似文献   

9.
如何平衡成本和精度之间的矛盾是区域土壤环境监测网构建亟待解决的技术难题。以广东省江门市耕地土壤砷含量为研究对象,开展基于三明治抽样的土壤环境监测点位优化研究。按照1 km×1 km网格在研究区域均匀布设3 375个点位,采用三明治抽样方法对其点位进行抽样优化,并运用Cochran公式、空间插值表征、交叉验证、独立验证等验证方法对不同期望精度下的抽样样本进行验证。结果表明,(1)期望精度为5%、10%、15%、20%的三明治抽样样本量分别为278、147、102、80个。(2)抽样结果的4种验证方法表明,期望精度为5%和10%的抽样样本能满足监测精度要求。该精度下样本量均满足利用Cochran经典公式在相应置信水平和相对误差条件下获取的合理采样数量,并且相应的半变异函数模型拟合度好、均方根误差值(RMSE)小、克里金插值代表性强。(3)期望精度为10%的抽样样本在保证监测精度不变的同时,大大降低了监测成本,其监测点位从3 375个降至147个,点位数量降低了96%。总之,抽样样本的期望精度值越小,监测精度越高。在江门市市域尺度上,期望精度为10%的三明治抽样是一种高精度、低成本、代表性强的土壤环境监测点位优化方法。  相似文献   

10.
利用长三角地区的128个国控大气监测站2014年11月到2015年1月的PM_(2.5)浓度逐时数据,采用地统计学方法进行了ρ(PM_(2.5))的空间异质性分析,并讨论了其动态变化的影响因素.结果表明,研究时段内ρ(PM_(2.5))的基底效应值在0.07—0.26之间,空间自相关性较强.块金值呈逐步变大趋势,表明PM_(2.5)人为源对其空间异质性的影响逐渐加强.ρ(PM_(2.5))变程值在217.1—336.2 km之间,东-西方向大于南-北方向.可依据各季节空气PM_(2.5)含量空间自相关距离的1/4—1/2进一步优化环境空气质量监测网点.根据普通克里格法空间插值结果得出,研究区PM_(2.5)污染呈片状分布,且PM_(2.5)污染程度持续加重,污染重心在苏锡常都市圈、南京都市圈和徐州都市圈,是空气PM_(2.5)污染防治的关键区域.南京都市圈和徐州都市圈可能受到WSW上风向外源输送的强烈影响,苏锡常都市圈则对SSE下风向的城市群构成较大的潜在影响.PM_(2.5)还与SO2、CO、NO2均呈显著正相关,表明研究区空气PM_(2.5)污染与化石能源燃烧和机动车尾气均有较大关系,也可能与SO2或NO2在不利气象条件下形成的二次气溶胶有关.  相似文献   

11.
A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.  相似文献   

12.
Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.  相似文献   

13.
Protected areas (PAs) are often implemented without consideration of already existing PAs, which is likely to cause an overrepresentation of certain biophysical conditions. We assessed the representativeness of the current PA network with regard to the world's biophysical conditions to highlight which conditions are underprotected and where these conditions are located. We overlaid terrestrial and marine PAs with information on biophysical conditions (e.g., temperature, precipitation, and elevation) and then quantified the percentage of area covered by the PA network. For 1 variable at a time in the terrestrial realm, high temperature, low precipitation, and medium and very high elevation were underrepresented. For the marine realm, low and medium sea surface temperature (SST), medium and high sea surface salinity (SSS), and the deep sea were underrepresented. Overall, protection was evenly distributed for elevation across the terrestrial realm and SST across the marine realm. For 2 variables at a time, cold and very dry terrestrial environments had mostly low protection, which was also the case for low SST and low and medium SSS across most depths for marine environments. Low protection occurred mostly in the Sahara and the Arabian Peninsula for the terrestrial realm and along the Tropic of Capricorn and toward the poles for the marine realm. Although biodiversity measures are of prime importance for the design of PA networks, highlighting biophysical gaps in current PAs adds a frequently overlooked perspective. These gaps may weaken the potential of PAs to conserve biodiversity. Thus, our results may provide useful insights for researchers, practitioners, and policy makers to establish a more comprehensive global PA network.  相似文献   

14.
Summary The adaptation of defensive secretions to their target organisms was examined for the abdominal gland secretions ofBledius furcatus, B. spectabilis andB. arenarius. Therefore the target organisms of the secretion of theseBledius species (i.e. their predators) had to be identified. At the collection sites examined these were the earwigLabidura riparia, the antCataglyphis bicolor, the flyLispe candicans, different carabids of the generaPogonus, Dichirotrichus, Dyschirius, Bembidion andCalathus and the wading birdsHaematopus ostralegus andCalidris alba. The secretion of the abdominal glands contains the toxin ptoluquinone dissolved in either-dodecalactone and 1-undecene (B. furcatus andB. spectabilis) or in octanoic acid and octyloctanoate (B. arenarius). The ratio of these solvents is species-specific. Application experiments using some of the natural insect predators (L. riparia, C. bicolor, Pogonus, Di. gustavii, Dyschirius) revealed that these solvent ratios provided a more effective deterrent than other possible ratios. Thus by combining the solvents in certain ratios, the capability of cuticular penetration and therefore the effectiveness of the defensive secretions are adapted to their natural targets.  相似文献   

15.
The politics of development includes subtexts of choice, as underpinned by community consensus (or lack of it), against the larger backdrop of a liberal democracy, with its intricate power structures that influence the choice of concepts and often lead to complicity rather than consent. A dilemma exists between the understanding of field-level practitioners and that of academics, whose understandings of progress differ. Progress can (and often does) imply long-term change across generations whereas development is often more a matter of crisis management and delivering tangible results to end-users. This makes it a bone of contention across political systems, irrespective of local or global dynamics. Development can emerge as a tool to be wielded for power and further political mileage at the expense of progress. Progress cannot be studied as a counterpoint to development as the sense of history is often missing in development interventions. Development tends to be piecemeal as its very logic often stems from the rationale of power. This is not to suggest, however, that development is only about politics; it is definitely more than the politics of everyday life and involves all of civil society that requires its critical and immediate attention. In this sense, it has become a priority for politicians with an underlying agenda designed to out-manouevre dissent and all statements of protest.  相似文献   

16.
An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.  相似文献   

17.
As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.  相似文献   

18.
Abstract: In the United States, as elsewhere, a growing debate pits national energy policy and homeland security against biological conservation. In rural communities the extraction of fossil fuels is often encouraged because of the employment opportunities it offers, although the concomitant itinerant workforce is often associated with increased wildlife poaching. We explored possible positive and negative factors associated with energy extraction in the Greater Yellowstone Ecosystem (GYE), an area known for its national parks, intact biological diversity, and some of the New World's longest terrestrial migrations. Specifically, we asked whether counties with different economies—recreation (ski), agrarian (ranching or farming), and energy extractive (petroleum)—differed in healthcare (gauged by the abundance of hospital beds) and in the frequency of sexual predators. The absolute and relative frequency of registered sex offenders grew approximately two to three times faster in areas reliant on energy extraction. Healthcare among counties did not differ. The strong conflation of community dishevel, as reflected by in‐migrant sexual predators, and ecological decay in Greater Yellowstone is consistent with patterns seen in similar systems from Ecuador to northern Canada, where social and environmental disarray exist around energy boomtowns. In our case, that groups (albeit with different aims) mobilized campaigns to help maintain the quality of rural livelihoods by protecting open space is a positive sign that conservation can matter, especially in the face of rampant and poorly executed energy extraction projects. Our findings further suggest that the public and industry need stronger regulatory action to instill greater vigilance when and where social factors and land conversion impact biological systems.  相似文献   

19.
Summary Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans,Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants fromThymus vulgaris andT. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, andCymbopogon nardus was compared. For both extracts,Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle.  相似文献   

20.
How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.  相似文献   

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