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1.
藏北地区生态与环境敏感性评价   总被引:5,自引:0,他引:5       下载免费PDF全文
藏北地区自然条件极为严酷,生态与环境非常脆弱和敏感。采用地理信息系统手段与综合评价方法,对藏北地区主要生态与环境敏感性问题进行评估,分析了土壤侵蚀、沙漠化和草地退化等方面的敏感性空间分异规律,指出了今后生态与环境建设的优先区域。结果表明:藏北地区土壤侵蚀敏感区占土地总面积的42.5%,主要分布于东中部区域;藏北地区沙漠化敏感区面积较大(占土地总面积的78.8%),主要分布在人类活动强度相对较低的西北部;藏北中东部和北部地区草地退化较为严重,尤其是藏北地区冰川与雪山及其周围等气候变化较为敏感区域和交通要道沿线等人类活动较为频繁区域的草地退化相对严重,对草地退化也比较敏感,是今后草地退化治理和恢复的优先区。  相似文献   

2.
ABSTRACT Telemetry data have been widely used to quantify wildlife habitat relationships despite the fact that these data are inherently imprecise. All telemetry data have positional error, and failure to account for that error can lead to incorrect predictions of wildlife resource use. Several techniques have been used to account for positional error in wildlife studies. These techniques have been described in the literature, but their ability to accurately characterize wildlife resource use has never been tested. We evaluated the performance of techniques commonly used for incorporating telemetry error into studies of wildlife resource use. Our evaluation was based on imprecise telemetry data (mean telemetry error = 174 m, SD = 130 m) typical of field-based studies. We tested 5 techniques in 10 virtual environments and in one real-world environment for categorical (i.e., habitat types) and continuous (i.e., distances or elevations) rasters. Technique accuracy varied by patch size for the categorical rasters, with higher accuracy as patch size increased. At the smallest patch size (1 ha), the technique that ignores error performed best on categorical data (0.31 and 0.30 accuracy for virtual and real data, respectively); however, as patch size increased the bivariate-weighted technique performed better (0.56 accuracy at patch sizes >31 ha) and achieved complete accuracy (i.e., 1.00 accuracy) at smaller patch sizes (472 ha and 1,522 ha for virtual and real data, respectively) than any other technique. We quantified the accuracy of the continuous covariates using the mean absolute difference (MAD) in covariate value between true and estimated locations. We found that average MAD varied between 104 m (ignore telemetry error) and 140 m (rescale the covariate data) for our continuous covariate surfaces across virtual and real data sets. Techniques that rescale continuous covariate data or use a zonal mean on values within a telemetry error polygon were significantly less accurate than other techniques. Although the technique that ignored telemetry error performed best on categorical rasters with smaller average patch sizes (i.e., ≤31 ha) and on continuous rasters in our study, accuracy was so low that the utility of using point-based approaches for quantifying resource use is questionable when telemetry data are imprecise, particularly for small-patch habitat relationships.  相似文献   

3.
    
ABSTRACT The Farm Bill conservation programs serve as the primary tools for the creation and improvement of wildlife habitat on working lands. Wildlife conservation would benefit from a working land-prioritization system that integrates these programs. We developed a Geographic Information System (GIS)–based system to prioritize land for inclusion in Farm Bill conservation programs. We designed the system to be applicable throughout the United States, to minimize potential conflicts of interest, and to facilitate simple implementation. We designated high conservation value (HCV) lands using habitats of greatest conservation need. We placed priority zones around HCV lands to determine high- and low-priority working lands. Nationwide implementation of this system would require gathering and manipulating data from multiple sources, as well as creation of a GIS layer denoting locations of working lands currently in conservation programs. This system would allow funding to be maximized through the ability to select participation based on property location and size, and to target landowners for participation. The wide-ranging potential benefits of this system make it well-suited for serving as the backbone to conservation on working lands.  相似文献   

4.
    
Global Positioning System (GPS) and very high frequency (VHF) telemetry data redefined the examination of wildlife resource use. Researchers collar animals, relocate those animals over time, and utilize the estimated locations to infer resource use and build predictive models. Precision of these estimated wildlife locations, however, influences the reliability of point-based models with accuracy depending on the interaction between mean telemetry error and how habitat characteristics are mapped (categorical raster resolution and patch size). Telemetry data often foster the assumption that locational error can be ignored without biasing study results. We evaluated the effects of mean telemetry error and categorical raster resolution on the correct characterization of patch use when locational error is ignored. We found that our ability to accurately attribute patch type to an estimated telemetry location improved nonlinearly as patch size increased and mean telemetry error decreased. Furthermore, the exact shape of these relationships was directly influenced by categorical raster resolution. Accuracy ranged from 100% (200-ha patch size, 1- to 5-m telemetry error) to 46% (0.5-ha patch size, 56- to 60-m telemetry error) for 10 m resolution rasters. Accuracy ranged from 99% (200-ha patch size, 1- to 5-m telemetry error) to 57% (0.5-ha patch size, 56- to 60-m telemetry error) for 30-m resolution rasters. When covariate rasters were less resolute (30 m vs. 10 m) estimates for the ignore technique were more accurate at smaller patch sizes. Hence, both fine resolution (10 m) covariate rasters and small patch sizes increased probability of patch misidentification. Our results help frame the scope of ecological inference made from point-based wildlife resource use models. For instance, to make ecological inferences with 90% accuracy at small patch sizes (≤5 ha) mean telemetry error ≤5 m is required for 10-m resolution categorical rasters. To achieve the same inference on 30-m resolution categorical rasters, mean telemetry error ≤10 m is required. We encourage wildlife professionals creating point-based models to assess whether reasonable estimates of resource use can be expected given their telemetry error, covariate raster resolution, and range of patch sizes. © 2011 The Wildlife Society.  相似文献   

5.
基于GIS长春市郊农地土壤肥力综合评价   总被引:6,自引:0,他引:6       下载免费PDF全文
以长春市郊区农地为例,应用ArcInfo进行空间数据采集、处理与分析,以土地利用类型作为评价单元,采用层次分析法确定评价因素的权重,引入模糊数学方法,建立各评价因素对肥力的隶属函数,计算各个肥力评价因素的评分,最后用指数和法求出各评价单元的综合评价值,根据综合评价值的大小划分土壤肥力等级,并分级统计其面积.应用ArcView GIS绘制了评价结果图.  相似文献   

6.
    
Abstract: We tested whether presence of white-winged doves (Zenaida asiatica) and mourning doves (Z. macroura) in South Texas, USA, was associated with any of the land cover types recorded in the 2001 National Land Classification Database. We used the point-transect method to conduct presence—absence surveys for both species at 236 points encompassing 744 observations. Within predefined land cover types surrounding each survey point, we used Geographic Information Systems to determine the proportions of each land cover type present. We used randomization tests to compare proportions of land cover types present at points with and without doves. We used Program DISTANCE to estimate dove densities at survey points and to test whether certain land cover types were associated with greater dove densities. Our results indicated white-winged dove occurrence in South Texas was positively associated with urban land and cropland, whereas mourning dove occurrence was positively associated with cropland. For land cover types found to be associated with dove presence, estimated density for each dove species increased as the proportion of associated land cover type increased. These results can assist wildlife biologists in the development of a more efficient and targeted protocol for censusing doves. In addition, our methods can be applied to other species across several geographic areas and landscape scales.  相似文献   

7.
    
We combined observations of bobcats (Lynx rufus) from bowhunters with remotely-sensed data to build models that describe habitat and relative abundance of this species in the agricultural landscape of Iowa, USA. We calculated landscape composition and configuration from publicly available land cover, census, road, hydrologic, and elevation data. We used multiple regression models to examine county-level associations between several explanatory variables and relative abundance of bobcats reported by surveyed bowhunters in each county. The most influential explanatory variables in the models were metrics associated with the presence of grassland, including Conservation Reserve, along with configuration of this perennial habitat with forests, although human population density and abundance of eastern cottontails (Sylvilagus floridanus) also correlated with abundance of bobcats. Validation of predictions against 3 years of independent data provided confidence in the models, with 66% of predictions within 1 bobcat/1,000 hunter-hours and 95% within 5 bobcats/1,000 hunter-hours of observed values. Once we accounted for landscape differences, no residual spatial trend was evident, despite relatively recent bobcat recolonization of Iowa. Models suggested that future range expansion of the bobcat population may be possible in some northern Iowa counties where habitat composition is similar to counties in southern Iowa where bobcats are abundant. Results from the county-level model have been useful to the Iowa Department of Natural Resources in evaluating the expansion of this once rare species and for delineating harvest opportunities. © 2011 The Wildlife Society.  相似文献   

8.
本文报告了西藏地区鹅膏菌属(Amanita)的真菌26种。其中灰鳞鹅膏菌(Amanita griseofarinosa Hongo),红鹅膏菌[A.parcivolvata(Peck)Glib.],浅杏黄鹅膏菌[A.Crocca(Quél.)Kühn.& Romagn.],黄赭毒鹅膏菌(A.flavorubescens Atk.),黄毒蝇鹅膏菌(A.flavoconia Atk.),史米斯鹅膏菌(A.smithiana Bas),褐黄鹅膏菌:(A.umbrinoluteaSeer.)等是我国新纪录种。西藏地区的首次新纪录13种。该属真菌均是树木的外生菌根真菌,有毒种多,具有重要的经济价值。  相似文献   

9.
    
ABSTRACT Because habitat loss and fragmentation threaten giant pandas (Ailuropoda melanoleuca), habitat protection and restoration are important conservation measures for this endangered species. However, distribution and value of potential habitat to giant pandas on a regional scale are not fully known. Therefore, we identified and ranked giant panda habitat in Foping Nature Reserve, Guanyinshan Nature Reserve, and adjacent areas in the Qinling Mountains of China. We used Mahalanobis distance and 11 digital habitat layers to develop a multivariate habitat signature associated with 247 surveyed giant panda locations, which we then applied to the study region. We identified approximately 128 km2of giant panda habitat in Foping Nature Reserve (43.6% of the reserve) and 49 km2in Guanyinshan Nature Reserve (33.6% of the reserve). We defined core habitat areas by incorporating a minimum patch-size criterion (5.5 km2) based on home-range size. Percentage of core habitat area was higher in Foping Nature Reserve (41.8% of the reserve) than Guanyinshan Nature Reserve (26.3% of the reserve). Within the larger analysis region, Foping Nature Reserve contained 32.7% of all core habitat areas we identified, indicating regional importance of the reserve. We observed a negative relationship between distribution of core areas and presence of roads and small villages. Protection of giant panda habitat at lower elevations and improvement of habitat linkages among core habitat areas are important in a regional approach to giant panda conservation.  相似文献   

10.
横断山地区石炭纪和二叠纪有孔虫   总被引:5,自引:4,他引:5  
横断山地区石炭纪和二叠纪海相沉积分布非常广泛,在早石炭世杜内期至晚二叠世各沉积中均含有大量有孔虫化石,其中尤以维宪期和长兴期沉积中的有孔虫化石最为丰富和保存极佳。本文描述了较为常见和特征的分子共11科30属65种,其中8个为新种,根据分析和比较,横断山地区石炭纪和二叠纪有孔虫动物群的组合面貌和特征与我国华南地区同期地层中所见有孔虫动物基本一致,同属“南方型”生物群,同时也与特提斯海域同期地层中有孔虫动物群非常近似,因此可以说明横断山地区当时的海水不仅与我国华南海域及特提斯海域都是相通的,同时都繁衍着大致相同的有孔虫动物群,它们均生活在温暖和盐度较为正常的浅海水域中。  相似文献   

11.
刘德旺  张树仁 《西北植物学报》2007,27(11):2320-2322
发现了分布于西藏的2个珍珠茅属新记录种:小型珍珠茅和毛果珍珠茅,并补充记载了2个新记录种的文献和标本引证。  相似文献   

12.
13.
列当科野菰属主要分布于南亚和东南亚,在西藏的分布为新记录。  相似文献   

14.
西藏新生代秋乌组孢粉化石的发现及其初步研究   总被引:7,自引:0,他引:7  
本文首次报道西藏雅鲁藏布江缝合带附近秋乌组含煤沉积中的孢粉化石。孢粉植物群主要由Quercoidifes,具孔类及三孔沟类花粉组成,包括12科26属及一些未定类群。组合中产有少量的Graminidites及Tsugaepollenites。植物群的总体特征显示其时代可能为渐新世至早中新世。秋乌组沉积早期的环境比较温暖。  相似文献   

15.
中国102个人群的身高与地理环境相关性研究   总被引:1,自引:0,他引:1  
本文对分布在中国16个不同行政区域的102个人群(汉族23个,少数民族79个)的人体发育指标—身高,应用地理信息系统(GIS)的空间分析功能和制图表达方法,对身高受地理环境因素影响的程度进行了综合分析。研究结果显示:随着地理纬度的升高,身高呈现逐渐增高的趋势。随着地区太阳总辐射量的增大,该地区的群体身高水平呈现增高的趋势;随着降雨量和湿度的增大,群体的身高水平呈现降低的趋势;随着地区平均风速指数的增加,身高亦呈现增高趋势。此外,研究还表明区域海拔和气压等因素对身高无明显影响。地理信息系统的技术与方法为分析人体身高发育受地理环境因素的差异性影响提供了新的技术手段和解决方案。  相似文献   

16.
  总被引:2,自引:0,他引:2  
Abstract 1 The western corn rootworm (WCR), Diabrotica virgifera virgifera Leconte (Coleoptera: Chrysomelidae), creates economic and environmental concerns in the Corn Belt region of the U.S.A. To supplement the population control tactics of the Areawide Pest Management Program in Brookings, South Dakota, Geographical Information Systems (GIS) were used to examine the spatial relationships from 1997 to 2001 between WCR population dynamics, habitat structure, soil texture and elevation. 2 Using the inverse distance weighted interpolation technique, WCR population density maps were created from georeferenced emergence and post‐emergence traps placed in maize fields. For each year, these maps were overlaid with vegetation, soil and elevation maps to search for quantitative relationships. 3 Through visual interpretation and correlation analysis, shifts in landscape structure, such as size, number and arrangement of patches, were shown to associate with WCR population abundance and distribution in varying degrees. Contingency analysis showed that WCR population abundance is associated with soil texture and elevation. 4 An understanding of the interactions between WCR population dynamics and landscape variables provides information to pest managers, and this can be used to identify patterns in the landscape that promote high insect population density patches to improve pest management strategies.  相似文献   

17.
    
The robust growth of coastal communities in the southeastern United States is putting unique pressures on estuarine resources. Urbanization of estuarine systems may alter ecosystem function and thus affect the spatial scale and magnitude of nutrient concentrations and primary production temporally and spatially. We examined the spatial and temporal patterns of nutrient and chlorophyll a (Chl a) concentrations in two shallow well-mixed estuaries, (1) a developed estuary, Murrells Inlet (MI), South Carolina, and (2) a relatively pristine estuary, North Inlet (NI), South Carolina. The summer chlorophyll a maximum in MI was characteristically higher than in NI, which may be indicative of eutrophication. Correlations between salinity and inorganic nutrients (N and P) suggest that nutrient import from upland sources may be more pronounced in MI during stochastic precipitation events. Although inorganic nutrient concentrations between the estuaries were similar overall, during a wet period, inorganic N concentration in MI was increased to a greater extent than in NI, while only minimal increases in inorganic P were observed in both estuaries. Chlorophyll a concentrations decreased from the dry to wet period. Geographic Information System (GIS) plots of intensive spatial sampling in MI indicated spatial gradients of nutrient concentrations within this estuary that appeared to be consistent over time. These observations were investigated in more detail using regression analyses to examine the influences of coastal dilution and nutrient sources on relationships between water quality constituents. Results indicate the importance of stochastic rain events in affecting the linkages of estuarine processes to upland runoff in the urbanized estuary, MI.  相似文献   

18.
Methods for establishing biodiversity conservation priorities are urgently required, as the number of species and habitats that are threatened increases relative to the material resources available for their conservation. The identification of priority areas demands the integration of biophysical data on ecosystems together with social data on human pressures and planning opportunities. But comprehensive and reliable data are rarely available to demarcate where the need for action is most urgent and where the benefits of conservation strategies can be maximized. Strategic conservation initiatives cannot wait for the creation of comprehensive databases. In order to fill the missing data gaps, the combined knowledge of local and technical experts can be used. This study presents a collaborative geographic information system (GIS) method for integrating the knowledge of local and technical experts with existing spatial environmental data to establish priority areas for biodiversity conservation. Procedures for structuring and framing the discussions, establishing assessment criteria, integrating knowledge with data, and building consensus are incorporated into the method. The method provides a novel cooperative mechanism to aid spatial knowledge management and inclusive biodiversity planning.  相似文献   

19.
由中国生态学会、中国生态经济学会、中国城市科学研究会联合召开的“全国城市生态科学讨论会”于1984年12月2—6日在上海复旦大学举行。到会的有来自19个省、自治区和市的从事生态、环保、地理、社会、经济和城市规划等24个专业的代表共80人,共收到学术论文43篇。中国生态学会理事长马世骏同志,中国生态经济学会副理事长兼秘书长王耕今同志,中国城市科学研究会秘书长李梦白同志主持了会议。首届全国城市生态科学讨论会的中心议题是:探讨城市生态学研究的目的、任务、对象和方法等基本理论问题,用城市生态学的观点分析我国不同类型城市在规划建设和管理中存在的重大问题;并就解决这些问题提出可行建议。  相似文献   

20.
梅花山生物多样性信息系统简介   总被引:4,自引:0,他引:4  
以梅花山国家级自然保护区生物多样性管理信息系统的建立和应用为例,论述了在自然保护区中建立生物多样性信息系统的意义、目的及实现的功能,提出了自然保护区生物多样性信息系统的组成和具体结构。  相似文献   

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