遥感技术在新疆阜康县草地估产中的应用研究

利用１９９１－１９９６年在阜康县不同草地类型上观测的草地产量、环境与遥感资料等,使用ＲＳ技术和ＧＩＳ系统进行了多重相关分析和遥感估产研究,并在处理,信息提取和遥感知识与草原生态结合方面有益探讨。结果表明,４个类型的鲜草产量与两种遥感绿度间存在着极显著相关性,display status     

典型草原植被生物量遥感监测模型——以锡林郭勒盟为例

以锡林郭勒盟典型草原为研究区域,将遥感技术用于草地牧草产量测量,分析了遥感植被指数与牧草产量之间的相关关系,比较和分析了3种植被指数的应用范围,研究了草地牧草产量遥感监测的方法,并利用遥感植被指数建立了草地牧草产量估产模型y=368.273x 2.973(R=0.908,R2=0.824),该模型通过2005年预测值与实测值的误差统计分析,2005年估产精度达到97%,研究还表明,锡林郭勒草地牧草产量估产的植被指数是归一化植被指数(NDVI).研究结果为今后开展大面积草地牧草产量估产和动态监测提供了有效途径.     

不同类型草地监测与估产遥感指标和光学模型建立的研究

对１９９１－１９９３年在新疆阜康县不同草地类型上观测的牧草产量、环境资料与地面光谱资料等进行的多重相关分析和光学模型建立的研究结果表明，不同类型的草地产量与各咱光谱工值间存在着显著相关性（Ｐ〈０．０５），相关系数（ｙ）均达到０．８４以上，且通过Ｆ检验。在找出影响牧草类型地面光谱绿度值的时空变化规律，建立了最优草地监测与估产指标和模型，其模型精度较高可用于草地资源大面积监测和估产。     

利用遥感环境资料进行草地大面积估产研究

利用１９９１￣１９９３年在新疆阜康县不同草地类型上观测到的牧草产量、环境资料与地面光谱、气象卫星资料等，进行了多重相关分析。结果表明，不同类型的草地产量和环境因子与各种遥感绿度值间存在着显著相关性（Ｐ〈０．０５），相关系数均达到０．４５以上，并通过Ｐ检验。在对草地气候因子和牧草产量动态变化的分析基础上，探索了牧草产量形成环境关系的机理分析与解释。进而，摸清了不同草地类型地面光谱绿度值的时空变化规律     

基于3S技术的甘肃省甘州区荒漠草地生产力评价

以荒漠草地为主的甘州区天然草原为研究对象,利用3S技术一体化集成平台,进行了甘州区荒漠草地植被指数的选择及提取、草地植物量估产模型的构建及验证,并对甘州区天然草地生产力进行了评价。研究结果显示,修正土壤调整植被指数(MSAVI)对甘州区低盖度荒漠草原植被具有较好的指示作用,MSAVI与产草量之间存在显著正相关(相关系数r=0.803,P<0.01);经实际测产验证,以MSAVI为基础建立的甘州区草地植物量估产模型,估产值与实测产量之间的平均误差为9.08%,比较准确地反映了甘州区天然草地产草量;经估算,甘州区天然草原总鲜草产量46.01万t,总可食鲜草产量26.81万t,理论载畜量为5.76万羊单位。     

草地遥感估产的原理与方法

在介绍草地遥感估产的原理和方法的基础上,分析了单纯的遥感模型、遥感模型与地学模型相结合等不同估产方法及草地面积动态监测的特点和存在问题,并对草地遥感估产方法发展趋势做了总结。随着遥感技术的发展,草地遥感估产技术和方法也将继续发展,基于遥感数据和方法的草地估产模型更加趋于成熟,其应用也将向草原生态系统、草地退化监测、草地植被生长监测等领域扩展。     

锡林郭勒盟草地植被生物量遥感监测模型的研究

以锡林郭勒盟为研究区域,将遥感技术用于草地地上生物量估算,分析了遥感植被指数与草地地上生物量之间的相关关系,比较和分析了三种植被指数的应用范围,研究了草地地上生物量遥感监测的方法,并利用遥感植被指数建立了草地地上生物量估算模型.研究表明:锡林郭勒草地地上生物量估产的植被指数是NDVI,其估产模型是"S"曲线,回归模型Y=e5.983-0.479/x(R=0.828, R2=0.685).     

基于MODIS-NDVI的天山北坡中段草地动态估产模型研究

利用EOS/MODIS卫星遥感数据,以天山北坡中段山地草原带为典型研究区,进行草地生物量变化动态监测。运用植被指数最大合成法,分析了研究区草地植被指数的时空变化特征,以及植被指数NDVI与地上生物量的相关关系,建立了MODIS NDVI在山地草甸草原、山地草原和山地荒漠草原上不同季节的生物量动态估测模型。结果表明：3种草地类型的最优动态估产模型分别是一元线性回归模型、二次曲线回归模型、幂函数曲线模型,估产精度分别达到83.06%、90.85%、88.06%。     

利用MODIS-NDVI进行草地估产研究--以内蒙古锡林郭勒草地为例

MODIS较高的空间分辨率(250 m/pixel)比AVHRR(1.1 km/pixel)在空间分析方面具有更高的精度.以内蒙古自治区锡林郭勒盟的温性荒漠草原、温性沙地典型草原、温性典型草原和温性草甸草原4种具有代表性的草地类型为例,以2002年5-9月的地面测产数据和同步MODIS遥感数据为基础,分别建立每类草地的草产量与MODIS-NDVI关系模型及4类混合的总模型.所有模型均通过0.01的极显著水平的F检验,不同模型拟合效果不同,R由0.55～0.87不等,分析得出:植被覆盖度大、空间分布均匀、NPP大的模型拟合效果好,反之则差.在此基础上初步探讨了利用MODIS-NDVI进行草地估产研究的可行性.     

基于MODIS的青海草原产草量及载畜平衡估算

为了科学合理地利用、管理草地,及时准确掌握草原产草量信息和载畜平衡状况,对保障草原的可持续发展具有重要意义。本研究利用2016年5-9月青海的MODIS NDVI、EVI数据和地面调查数据,按草地类型分别建立可食草鲜草产量的估算模型,通过比较基于NDVI和EVI建立的不同产草量估算模型的精度,选出了各类型草地的最优估产模型。在此基础上,计算了不同类型草地的干草产量,并结合畜牧业统计数据估算了青海牧区和半牧区各县(市)的载畜平衡情况。结果表明,1)基于NDVI的可食鲜草产量估算模型精度普遍高于基于EVI的模型,但各类型草地的最优估算模型不同。2)2016年青海省草原干草总产量空间分布差异明显,干草单产在1 200kg·hm-2以上的草地主要分布在东部的禾草草原和高寒草原,干草单产在300kg·hm-2以下的草地主要分布于北部的高寒荒漠以及西部的盐生草甸和高寒草原。对总产草量贡献最大的为高寒草甸,占70.35%。3)2016年青海省29个半牧区和牧区的县(市)中,有21个县(市)为载畜平衡或载畜不足,8个县(市)为超载,并且载畜平衡状况与存栏牲畜密度具有较好的对应关系。     

Heartworm in dogs in Canada in 1984

In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.

Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.

     

Heartworm in dogs in Canada in 1983

In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario.

Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously.

     

Heartworm in dogs in Canada in 1991

In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium.     

Heartworm in dogs in Canada in 1985

In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).

Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1988

In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%).     

Heartworm in dogs in Canada in 1989

In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.

Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.

     

Heartworm in dogs in Canada in 1987

In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%).     

Heartworm in dogs in Canada in 1986

In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).

Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.