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 171 毫秒
1.
Research on ecosystems patterns and dynamics is critical for understanding the regional problems of resources and environment. In this study, based on the technology of RS and GIS, the composition, patterns and dynamics of the ecosystems in Haihe river basin during 1990–2005 were analyzed using landscape indices including the area of average patches, aggregation index and Shannon–Weaver diversity index. According to the development situation of economy and society in Haihe river basin, some driving factors for dynamics of ecosystems patterns were concluded based on correlation analysis. Results showed that the ecosystems patterns in Haihe river basin changed greatly from 1990 to 2005. The area of urban and grassland increased, but farmland, forest and wetland decreased. As for landscape indices, the area of average patches, value of aggregation index, clump index and diversity index all increased, indicating the trend of evenness for the whole ecosystems. Growth of population, economy growth together with urbanization and policy were the main driving factors for dynamics of ecosystem pattern in this basin.  相似文献   

2.
3.
Research on ecosystems patterns and dynamics is critical for understanding the regional problems of resources and environment. In this study, based on the technology of RS and GIS, the composition, patterns and dynamics of the ecosystems in Haihe river basin during 1990–2005 were analyzed using landscape indices including the area of average patches, aggregation index and Shannon–Weaver diversity index. According to the development situation of economy and society in Haihe river basin, some driving factors for dynamics of ecosystems patterns were concluded based on correlation analysis. Results showed that the ecosystems patterns in Haihe river basin changed greatly from 1990 to 2005. The area of urban and grassland increased, but farmland, forest and wetland decreased. As for landscape indices, the area of average patches, value of aggregation index, clump index and diversity index all increased, indicating the trend of evenness for the whole ecosystems. Growth of population, economy growth together with urbanization and policy were the main driving factors for dynamics of ecosystem pattern in this basin.  相似文献   

4.
Teleconnection between the early immigration of brown planthopper (BPH) and El Nino/Southern Oscillation (ENSO) indices from January of two years previously to the current June was investigated to make long-term forecast. The teleconnection results were as follows: ENSO indices which were significantly correlated with the early immigration of BPH were primarily sea surface temperature anomalies (SSTA) in N3, N4 and N3.4 regions, accounting for 71.8% of the total. Significant ENSO indices from two years and one year before the immigration events had a proportion of about 84%, while those in the current year only accounted for 16.7%. There was significantly negative correlation between the early immigration of BPH and SSTA in each Nino region from two years before to the previous spring, whereas there was significantly positive correlation between these two factors during the period from the previous winter to the current spring. The significant correlation between the early immigration of BPH and SSTA in each Nino region in the last summer and autumn did not show any obvious tendencies. The relationship between the southern oscillation index (SOI) and the early immigration of BPH was opposite to that between the immigration and SSTA in each Nino region. The above mentioned significant ENSO indices were used as key factors to build forecasting models for the early immigration of BPH by step-wise multiple linear regression analysis. Finally, 12 integrated forecasting models were obtained, which could make predictions 3–27 months ahead and had a predictive accuracy of 88.9%.  相似文献   

5.
Teleconnection between the early immigration of brown planthopper (BPH) and El Nino/Southern Oscillation (ENSO) indices from January of two years previously to the current June was investigated to make long-term forecast. The teleconnection results were as follows: ENSO indices which were significantly correlated with the early immigration of BPH were primarily sea surface temperature anomalies (SSTA) in N3, N4 and N3.4 regions, accounting for 71.8% of the total. Significant ENSO indices from two years and one year before the immigration events had a proportion of about 84%, while those in the current year only accounted for 16.7%. There was significantly negative correlation between the early immigration of BPH and SSTA in each Nino region from two years before to the previous spring, whereas there was significantly positive correlation between these two factors during the period from the previous winter to the current spring. The significant correlation between the early immigration of BPH and SSTA in each Nino region in the last summer and autumn did not show any obvious tendencies. The relationship between the southern oscillation index (SOI) and the early immigration of BPH was opposite to that between the immigration and SSTA in each Nino region. The above mentioned significant ENSO indices were used as key factors to build forecasting models for the early immigration of BPH by step-wise multiple linear regression analysis. Finally, 12 integrated forecasting models were obtained, which could make predictions 3–27 months ahead and had a predictive accuracy of 88.9%.  相似文献   

6.
Dramatic changes in land use have occurred in arid and semi-arid lands of Asia duringthe 20th century. Grassland conversion into croplands and ecosystem degradation is widespreaddue to the high growth rate of human population and political reforms of pastoral systems. Rangeland degradation made many parts of this region vulnerable to environmental and political changes. The collapse of the livestock sector in some states of central Asia, expansion of livestockin China and intensive degradation of grasslands in China are examples of the responses of pastoral systems to these changes over the past decades. Carbon dynamics in this region is highly variable in space and time. Land use/cover changes with widespread reduction of forest and grasslands increased carbon emission from the region.  相似文献   

7.
武晓东  傅和平  保平  甘红军 《兽类学报》2004,24(4):365-368,349
The rodents were investigated with trap-day method in Mashan Desert of Inner Mongolia from August to September 1998 and 1999. Sixty-five sites were selected according to conditions of vegetation, landform, topography and soil. The area of the site was 10 ha in which 400 - 500 traps were arranged. There were 1019 samples captured with 31 469 effective trap-days in all sites.The results showed that Meriones meridianus was a typical dominant species and Euchoreutes naso was one of representative rodents in Mashan Desert. The Mashan Desert was a new distribution region of Salpingotus crassicauda in China. Therefore, geographical distribution of the three rodents was analyzed with Map-info Professional 6.5 software of GIS (Geographical Information System).The results showed that the distribution maps of the three rodents, which were obtained on the basis of GIS, not only told the information of prophetical distribution of the three rodents in Mashan Desert, but also reported information of the rodents‘ distribution affected by habitat change, which can not be obtained by traditional site-distribution ways. This result can be used as scientific foundation for perfecting research design and monitoring harmful rodents in future.  相似文献   

8.
Spatial and temporal patterns of insect damage in relation to aflatoxin contamination in a corn field with plants of uniform genetic background are not well understood. After previous examination of spatial patterns of insect damage and aflatoxin in pre-harvest corn fields, we further examined both spatial and temporal patterns of cob- and kernel- feeding insect damage, and aflatoxin level with two samplings at pre-harvest in 2008 and 2009. The feeding damage by each of the ear/kernel-feeding insects (i.e., corn earworm/fall armyworm damage on the silk/cob, and discoloration of corn kernels by stink bugs) and maize weevil population were assessed at each grid point with five ears. Sampling data showed a field edge effect in both insect damage and aflatoxin contamination in both years. Maize weevils tended toward an aggregated distribution more frequently than either corn earworm or stink bug damage in both years. The frequency of detecting aggregated distribution for aflatoxin level was less than any of the insect damage assessments. Stink bug damage and maize weevil number were more closely associated with aflatoxin level than was corn earworm damage. In addition, the indices of spatial-temporal association (χ) demonstrated that the number of maize weevils was associated between the first (4 weeks pre-harvest) and second (1 week pre-harvest) samplings in both years on all fields. In contrast, corn earworm damage between the first and second samplings from the field on the Belflower Farm, and aflatoxin level and corn earworm damage from the field on the Lang Farm were dissociated in 2009.  相似文献   

9.
The characteristic of change in value of Tarim River ecosystem service function and its causes are discussed by combining the remote-sensing images with social statistical data related to the change in land utilization of Tarim River Main stream area during 1973–2005 and applying correlation analysis, regressional analysis and principal component analysis methods. The results show a right ascension state in the value of Tarim River ecosystem service function over the past 30 years. Of which, the Cropland ecosystem service function is of the largest increment in the economic value, which is far in excess of other ecosystem systems; the capacity of forest, grassland and wetland in service supply and value attribution show a downward tendency relatively; the area of Cropland and unused land ecosystems increase while that of forest, grassland and wetland ecosystems decrease, which indicates that the integral capacity and balance of the ecosystem in the region investigated has been affected severely and the ecosystem deteriorated; the economic activity of human is the key factor to regulate the change in economic value of Tarim River ecosystem service function and its trend in development.  相似文献   

10.
The characteristic of change in value of Tarim River ecosystem service function and its causes are discussed by combining the remote-sensing images with social statistical data related to the change in land utilization of Tarim River Main stream area during 1973–2005 and applying correlation analysis, regressional analysis and principal component analysis methods. The results show a right ascension state in the value of Tarim River ecosystem service function over the past 30 years. Of which, the Cropland ecosystem service function is of the largest increment in the economic value, which is far in excess of other ecosystem systems; the capacity of forest, grassland and wetland in service supply and value attribution show a downward tendency relatively; the area of Cropland and unused land ecosystems increase while that of forest, grassland and wetland ecosystems decrease, which indicates that the integral capacity and balance of the ecosystem in the region investigated has been affected severely and the ecosystem deteriorated; the economic activity of human is the key factor to regulate the change in economic value of Tarim River ecosystem service function and its trend in development.  相似文献   

11.
根据草地畜牧业的特点,建立了以草地、家畜、饲料储备和牧区人文经济为主体的四类三级雪灾评价指标体系。通过格栅获取法和模糊Borda数分析法,确定了指标体系各因素的权重,建立了雪灾对草地畜牧业影响的定量评价和雪灾损失计算模型。提出了以载畜量、受灾面积、积雪与牧草高度之比和气候为变量因子的不同等级雪灾损失指数模型。用模糊评价和德尔菲法相结合的方法,综合评价了雪灾对草地畜牧业的影响。结果表明:雪灾对草地畜牧业的有利影响度为0.481,不利影响度为6.8。以新疆阿勒泰地区为例,估算了该区2000年雪灾对草地畜牧业影响的综合评价值和损失率,取得了较好的效果。  相似文献   

12.
阿勒泰地区雪灾遥感监测模型与评价方法   总被引:7,自引:2,他引:5  
利用我国新疆阿勒泰地区1996~1997年两次雪灾期问的NOAA卫星数据及地面气象台站观测资料,建立了积雪深度遥感反演模型;利用线性混合光谱分解原理,研究了基于像元的积雪覆盖率及积雪空间分类算法;提出评价积雪对草地畜牧业危害程度的两种基于格网数据结构的定量化指数.结果表明,通过积雪深度反演模型和线性混合光谱分解方法可计算基于像元的积雪深度和覆盖率,提高积雪分类的精度.建立的基于格网单元的积雪危害指数模型可系统地表达积雪区的雪情、草情、畜情和气象因子的空间分布状况,综合反映积雪对草地畜牧业的危害程度。  相似文献   

13.
利用我国新疆阿勒泰地区1996~1997年两次雪灾期间的NOAA卫星数据及地面气象台站观测资料,建立了积雪深度遥感反演模型;利用线性混合光谱分解原理,研究了基于像元的积雪覆盖率及积雪空间分类算法;提出评价积雪对草地畜牧业危害程度的两种基于格网数据结构的定量化指数.结果表明,通过积雪深度反演模型和线性混合光谱分解方法可计算基于像元的积雪深度和覆盖率,提高积雪分类的精度.建立的基于格网单元的积雪危害指数模型可系统地表达积雪区的雪情、草情、畜情和气象因子的空间分布状况,综合反映积雪对草地畜牧业的危害程度.  相似文献   

14.
北疆牧区雪灾预警与风险评估方法   总被引:5,自引:0,他引:5  
在分析北疆牧区畜牧业生产与雪灾分布特征的基础上,利用RS、GIS和地面监测资料,从草地抗灾力、家畜承灾体和积雪致灾力3个子系统中选择9个因素作为预警参评因子,用家畜死亡率作为风险评估因子,构建了一个在完全放牧状态下的牧区雪灾预警与风险评估体系和模式.采用多层次综合法和目标线性加权函数法,建立了雪灾预警分级模型、判别模型和风险评估模型,据此可对草地和家畜抵御雪灾的强度和雪灾的风险期望损失进行动态预警与评估.北疆牧区雪灾预警与风险评估模型的精度分别达85%和72%.  相似文献   

15.
侯丽丽  都瓦拉  银山  玉山 《生态学报》2022,42(3):1059-1070
草原火灾给牧区人民生命财产及牧区生境带来了严重的威胁。以牧区村落汗敖包嘎查为例,从牧户微观尺度出发,基于实地调查获取的牧民社会经济数据,并结合气象和遥感数据,运用自然灾害风险指数法、主成分分析法和加权综合法构建了汗敖包嘎查草原火灾风险评价指标体系,获取了汗敖包嘎查草原火灾风险分布图。结果表明:汗敖包嘎查草原火灾风险从中部地区向四周递减,西北部地区风险高于东部、南部地区,中、高风险区占研究区总面积的49.85%。研究结果从微观尺度为草原火灾风险评价提供了新的视角和参考。  相似文献   

16.
草原毛虫Gynaephora qinghaiensis是分布在我国青藏高原高寒牧区的一种重要害虫,对高寒草甸植被破坏相当严重。为调查青藏高原高寒牧区草场草原毛虫的分布与危害情况,本研究在青海省玉树州的高寒牧区布设了10个调查样地,连续5年(2015-2019年)采用随机抽样的方法调查了草原毛虫种群密度,并于2016年同步调查了草原毛虫生境植被指数,并对2016年不同调查样地的草原毛虫种群密度与生境植被指数之间的相关关系进行了分析。调查结果显示,10个调查样地的草原毛虫种群密度在1.0~200.6 头/m^2之间,具有聚集性分布的特点,集中分布在治多草原、嘉塘草原和隆宝草原。根据高寒草甸草原毛虫危害等级划分标准,30%调查样地达到重度、极重度危害等级。相关分析结果显示,草原毛虫种群密度与植被总盖度之间呈极显著的负相关关系(P<0.01),表明随着草原毛虫种群密度的增大,草甸植被总盖度总体呈逐渐减小的趋势。总之,玉树州高寒牧区草场草原毛虫种群分布相对集中,密度较高,对草场植被危害严重,需及时采取有效措施予以治理。本研究对草原毛虫种群分布及其生境植被展开的基础调查工作可为草原毛虫灾害的预测预报以及草原毛虫的防控提供科学的基础数据,对保护青藏高原高寒牧区草场生态环境具有重要的意义。  相似文献   

17.
李刚勇  陈春波  李均力  彭建 《生态学报》2023,43(16):6889-6901
低空域无人机遥感技术具有高时效性、高分辨率、低成本、易操控等优势,作为地面与高空遥感(航天与航空遥感)间测量尺度空缺的有益补充,低空无人机遥感扩展了样地样方空间尺度,提高了中、小尺度遥感观测信息的精细化程度,实现了草原生境信息的快速采集、处理与分析应用,是草原"星-空-地"一体化监测的重要组成。针对草原监测评价,总结了国内外低空无人机遥感在草原基况调查(草原草层高度监测、草原植被覆盖度监测与草原地上生物量估算)、草原动态监测(草原植被长势监测、草原产草量估测与草畜平衡监测)和草原应急管理(草原火灾、雪灾与生物灾害监测)中的应用。结合大数据、人工智能、云计算与物联网等新型技术,分析了低空无人机遥感在草原生态监测领域存在的不足和未来的发展方向,以期为低空无人机遥感关于草原监测评价与智慧草原的后续研究提供参考。  相似文献   

18.
福建东山岛灾害生态风险的时空演化   总被引:1,自引:0,他引:1  
将福建省东山岛作为灾害的承灾系统,以1994年、2003年及2011年3期遥感影像为基础,选择暴雨和大风作为东山岛主要灾害,从承灾系统脆弱性、承灾系统应灾力、承灾系统恢复力3个方面选择指标构建东山岛灾害生态风险评估指标体系,分别获得东山岛1994年、2003年和2011年3期暴雨和大风灾害生态风险图,结果表明:东山岛1994、2003、2011年暴雨和大风灾害生态风险格局均随时间出现明显变化;总体来看,东山岛西北部主要低山森林地带风险值较低,整体生态环境和抗灾能力较好,东北部城镇集中区和沿海地带风险值较高,生态环境质量和抗灾能力较低;东山岛17a来的人为干扰存在正负效应,长期生态建设使得东山岛西北部主要低山森林地带风险值下降,但大规模的城镇建设,旅游、养殖、房地产等对沿海地带的干扰,造成东北部城镇集中区及东部沿海地带风险值上升。  相似文献   

19.
神农架川金丝猴栖息地植物区系特征及食物资源研究   总被引:1,自引:0,他引:1  
2008年春季我国南方特大冰雪灾害,给受灾林区的森林生态系统及野生动物造成了巨大影响。神农架是川金丝猴分布的最东端,也是重灾区之一。该文基于灾前两年的实地调查资料,对神农架川金丝猴栖息地植物区系进行分析,以期为灾后生物多样性的检测评估及川金丝猴栖息地恢复建设提供依据。实地调查发现,川金丝猴栖息地内木本植物共有255种,隶属44科105属,其中乔木23科51属129种,灌木22科49属113种,木质藤本7科9属13种;据统计在栖息地内共有31科58属85种川金丝猴的食源植物。该区植物区系中温带分布性质的属占优势,有58个,占属数的56.30%;热带分布性质的属有22个,东亚和中国特有分布成分共有23个属,分别占属数的21.36%和22.33%;显示了该区地处亚热带与温带的过度性质。还统计了栖息地食源植物区系谱,分析了该区域食源植物特点。  相似文献   

20.
牧区妇女社会地位的高低对草地生态系统健康具有重要的影响。以祁连山区的天祝藏族自治县抓喜秀龙乡为调查研究区域,随机抽取100户藏族牧户为研究对象,采用问卷、座谈和关键人物座谈等形式,对妇女在社会生产中充当的角色、日常生活中承担的家务状况、受教育程度、参与社会活动情况以及对草地政策的认知等方面进行了系统调查和分析。研究结果表明:在农村社会变革中,女性是畜牧业生产的主力军,承担着将近80%的生产管理工作,74.3%的日常家务。其在家庭经济中的决策权和农村社会中的地位也在逐渐提高,在经济方面占36.5%的支配权,拥有14.5%的决策权。但是,妇女的受教育的程度普遍较低,女性的文盲率达14.4%。因此,妇女对草地生产管理技术的接受程度较低,对草原管理方面的政策及相关的法规缺乏认识,这将会对牧区草地畜牧业的可持续发展产生潜在影响。  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