呼伦贝尔草甸草原地上净初级生产力对气候变化响应的模拟

利用内蒙古呼伦贝尔草原额尔古纳右旗牧业气象试验站1994-2009年牧草生长季逐月实测资料,对CENTURY模型进行检验,模拟了呼伦贝尔草甸草原1961-2010年间地上净初级生产力(ANPP)动态,并与26个气象因子进行相关性分析。模型检验结果显示,生长季内逐月地上生物量模拟值与观测值之间的相关系数为R²=0.53,斜率b=0.94,误差平方根值为72.07 g/m²,平均绝对百分比误差为38.02%。检验结果表明,CENTURY模型能够成功地模拟这类草原的季节动态和年际变化。在过去的50年中,呼伦贝尔草甸草原温度增加,降水略增,ANPP增加。相关分析表明,ANPP与生长季降水量(r=0.372)呈极显著正相关;与年平均最低气温、年平均地面气温、年平均气温、7月降水量呈显著正相关;与年平均风速(r=-0.382)呈极显著负相关;与其他气象因子无显著的相关关系。应用区域气候模式系统PRECIS输出的2021-2050年气候情景数据分析得出,在SRES B2、A2和A1B情景下,未来呼伦贝尔草甸草原平均最高气温和最低气温都将呈显著升高趋势,降水量略增,ANPP虽然在年际间存在波动,但总体呈明显增加态势,分别较基准时段增加了67.14%,69.65%和76.58%,增加速率分别为16.51,17.34和16.42 g/(m²·10 a)。在3种情景下,未来气候变化均会对呼伦贝尔草甸草原群落生产力产生显著的正面影响。     

探讨不同气候变化对内蒙古西部荒漠草原牧草生产力的影响

随着气候的不断变暖,牧草生产力受气候变化的影响逐渐受到社会人士和一些学者的注意,随之,气候生产力的大小也成为生态研究的重要领域。内蒙古荒漠草原是一种旱生性非常强的草原生态系统,它是草原向荒漠过渡的产物,并且其对天气的依赖性比较大。本文将通过对不同气候条件之下的内蒙古西部荒漠草原的介绍,对气候变化使得内蒙古西部荒原草原牧草生产力的影响做出简要的分析和探讨。     

近40年西乌珠穆沁旗牧草气候生产力变化特征分析

本文通过整理西乌珠穆沁旗近40年年均气温及年均降水量变化,利用Thorntn waite Menorial模型计算出该旗近40年的牧草气候生产力(FPCP)数据,并通过sas软件处理得出温度、降水与牧草气候生产力之间的回归模型。通过回归模型分析牧草气候生产力的变化特征、趋势,并分析气候因子对它的影响程度。分析结果表明:(1)近40年该旗年均气温增温趋势明显,增温率为0.41℃/10a。对牧草气候生产力的影响为2.3%。降水变化幅度比较大从2.31mm到240.79mm,对牧草气候生产力的影响为从0.37%到38.1%。降水是影响牧草气候生产力的关键因子;降水变化对FPCP的影响大于温度变化对FPCP的影响。(2)近40年西乌珠穆沁旗牧草气候生产力平均值为5660.13kg/hm2,前25年呈波浪形变化,出现增长趋势,后15年出现下降趋势,总体上与降水变化吻合。     

气候变化对三江源兴海县草地气候生产潜力的影响

利用三江源区兴海县草原区46年的气候资料,分析了气温、降水的变化趋势及其对草地气候生产潜力的影响.结果表明:三江源区兴海县气候总体上呈暖干化趋势,46年来年平均气温上升了1.6℃,平均每10年升高0.35℃;年降水量变化总体上呈不显著的增加态势,增加幅度为2.1mm/10a;草地气候生产力呈增加趋势.降水量是影响该地区草地气候生产潜力的关键因子,未来"暖湿型"气候对兴海草地干物质生产有利,平均增产幅度为2%～4%,而"冷干型"气候对草地的干物质生产最为不利,平均减产幅度为3%～7%.若气温升高1～2℃、降水量增加10%～20%,则兴海草地的气候生产力将增加2%～4%.     

2011-2020年夏季全国草原净初级生产力时空变化及其气象影响评估

为评估2011—2020年夏季全国草地净初级生产力时空变化以及气象条件对净初级生产力的影响,本研究依据气象站逐日气象观测资料以及中分辨率成像光谱(Moderate-resolution imaging spectroradiometer,MODIS)系列卫星资料遥感数据,分析了近10年夏季全国草地净初级生产力变化。结果表明:2011—2020年夏季全国草原净初级生产力总体呈现增加趋势,平均每年增加0.2 gC·m^-2·a^-1,内蒙古中部、甘肃东部、青海东部、西藏东部等地近10年草原净初级生产力明显增加。近10年全国大部草原区平均气温和降水量均呈增加趋势,较好的气象条件利于夏季牧草生长。2020年夏季全国草原区的气温和降水量也较常年偏高,北方草原区草地平均净初级生产力为121.3 gC·m^-2·夏季^-1,为近10年偏好年份。2011—2020年夏季全国草原净初级生产力呈增加趋势,较好的气象条件对其贡献较大。     

气候变化对甘肃玛曲草原生态的影响

采用甘肃省玛曲县1967年至2005年的年降水、气温、大风、沙尘等气候资料和1997～2005年卫星数据资料(NOAA14-AVHRR和EOS-MODISD),分析了玛曲草原38年来的气候演变特征和近10年来的草地植被月及年与相同时相降水之间的关系.结果表明:玛曲在降水量减少、气温升高的气候条件下,大风沙尘天气却显著减少;秋季降水出现明显转型信号,从90年代中期转入连续增加;近10年中,草原植被1997～2001年逐年显著减少(除个别年份随年降水波动外),2000年最差,草原沙漠化占总面积的5%,退化面积高达45%;2001～2005年间牧草植被缓慢恢复,呈现不显著的增加趋势,增加的变幅总体小于减少的变幅.     

2007年春季全国大部分草原牧草长势较好

农业部草原监理中心对2007年春季全国草原气象条件和牧草长势进行了监测,结果表明:2007年入春以来,我国草原大部分地区降水量较常年同期偏多,也多于去年同期,且降水时段分配比较均匀,3月以来气温呈前春偏低、仲春以来偏高的态势,总体热量条件优于常年,由于水热匹配,水分条件有利于牧草返青生长,牧草长势好于去年和常年。气象条件评价:1)水分条件。自3月份以来,全国大部分草原地区出现了近年来少见的多雨(雪)过程,降水量明显多于常年同期,部分地区比常年偏多5成以上,为牧草返青提供了良好墒情,有利于牧草返青生长。其中内蒙古东北部和西部、…     

内蒙古东部气候变化及其草地生产潜力的区域性分析

运用48个气象站点1961～2005年间的气象观测资料,在以聚类分析方法对内蒙古东部草原区进行气候分区的基础上,以Thornthwaite Memorial模型作为草地生产潜力估算指标,运用典型相关分析方法分析了各区年平均气温、年平均最高气温、年平均最低气温与年降水量的变化特征及其与草地生产潜力趋势的关系.结果表明,在大兴安岭中部地区,气温与降水有不断增加的潜势,草地生产力增长趋势明显,而在大兴安岭南麓与西侧的草地区域,气候变化呈暖干化趋势.降水是草地生产力提高的限制性因素.     

内蒙古荒漠草原不同等级降水时空变化特征

根据内蒙古荒漠草原11个气象观测站1961~2010年逐日降水资料,采用线性倾向估计、趋势分析、反距离权重(IDW)差值法,分析内蒙古荒漠草原50 a不同等级降水贡献率及降水日数的时空变化特征。结果表明:(1)内蒙古荒漠草原以日降水量≤5mm的降水事件为主。各级降水对总降水量的贡献率大小依次为中雨>小雨>小到中雨>大雨>微雨>暴雨>大暴雨;(2)近50年微雨、小雨的贡献率波动中减少,中雨的贡献率增加;(3)微雨、小雨、小到中雨日数均呈弱减少的趋势,仅中雨日数呈增加趋势,但不显著,主要分布在荒漠草原中南部和北部;(4)空间上,微雨、小雨、小到中雨的降水日数呈现由南向北逐渐减少的分布特征;中雨日数最多分布在草原区西南部。小降水事件(≤5mm降水)对荒漠草原生态系统具有显著的生态作用,研究结果可为当地畜牧业生产提供科学参考。     

内蒙古农牧交错区草地气候生产力对气候变化的响应

摘要：本研究以太仆寺旗为例,利用1979-2009年的气候数据,分析了内蒙古农牧交错区气候变化趋势,并结合Miami和Thornthwaite Memorial模型研究草地气候生产力对不同气候变化情景的响应。结果表明,近30年来,太仆寺旗年平均气温增温趋势明显（每10年0.62 ℃）,四季平均气温均有显著上升,以冬季升温最明显（每10年0.84 ℃）;年降水量有下降趋势（每10年5.3 mm）,但趋势不明显;综合考虑水热因子的Thornthwaite Memorial模型更能够反映草地气候生产力的变化趋势,与温度相比,降水是影响草地生产力的关键因子;在气候变暖的背景下, “暖湿型”气候可提高草地气候生产力,变化幅度为8.3%~16.7%,假如未来气候向“暖干型”发展,草地气候生产力的变化为-4.8%~3.5%。     

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 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 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 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 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.