坡位对高寒草甸山体断面重建植被及土壤性状的影响

针对川西高寒草甸公路山体断面植被重建的实际技术需求,以G248国道建成3年的护坡草坪植被为样地,通过测定4个坡位（上坡、中坡、下坡和坡底）群落特征、优势种种类、功能群重要值及草坪草性状等植被指标,以及颗粒组成和理化性状等土壤指标,研究坡位对重建植被结构和土壤性状的影响。结果表明：1）低坡位可增加护坡植被的群落密度和投影盖度（P<0.05）,但下坡植被基盖度和物种多样性、丰富度、均匀度均最大。2）坡位越低优势种占物种数比例越低,下坡群落高度和第一优势种高度显著低于其他坡位（P<0.05）。3）坡位越低草坪草存活密度、自然高度、分蘖数、生物量和重要值越大（P<0.05）,草坪草重要值仅0.04%～16.52%,4个坡位均演替为以乡土植物为主的植被群落。4）坡位显著影响生活型功能群组成（P<0.05）,4个坡位中多年生杂类草重要值均为最大,下坡6种生活型功能群组成较为均衡。5）坡位显著影响土壤颗粒组成和理化性状（P<0.05）,坡位越高土壤粒级组成越失衡,有机质含量越低且保水供肥能力越差。综上,坡位影响再生植被的群落特征、功能群结构、优势种种类及土壤粒级组成和理...     

白龙江中游地震滑坡体植被初期的自然恢复能力——以陇南市武都区清水沟滑坡体为例

在野外样方调查的基础上,对陇南市武都区清水沟地震滑坡体上的植物群落组成以及物种多样性进行详细调查和统计分析。结果表明,1)研究区域内植被自然恢复以草本植物为主,有26种,占研究区植物总数的76.5%,灌木较少,有8种,无乔木分布,植物群落组成以草本和小灌木为主,其中优势种为狗牙根(Cynodon dactylon)、马唐(Digitaria sanguinalli)、黄茅(Heteropogon contortus)、芦苇(Phragmites australis)、骆驼蓬(Peganum harmala)等;2)由于环境因子的差异,不同立地条件植物群落物种组成、群落类型以及群落结构存在差异;3)不同立地条件的环境因子不同,特别是水热光照条件组合存在差异,导致不同立地条件下植物群落的自然恢复能力存在明显差异,其自然恢复能力和抗干扰能力指数大小表现为中坡位下坡位上坡位。     

皖北石灰岩山地不同植被恢复模式对植物群落物种组成及多样性的影响

通过研究皖北石灰岩山地生态系统的植被群落,分析不同植被恢复群落的组成、结构、多样性和生活型组成,进而阐明石灰岩山地生态系统植被恢复模式对群落结构特征以及植物物种多样性的影响。结果表明:研究区有54种植物,隶属26科54属。侧柏(Platycladus orientalis)+构树(Broussonetia papyrifera)人工混交林有植物种类16科26种,分别占总数的61.5%和48.1%。酸枣(Ziziphus jujuba var.spinosa)+牡荆(Vitex negundo var.cannabifolia)灌丛和荩草(Arthraxon hispidus)+牡荆草灌丛植物种类分别为32和33种,分别占调查总物种数的59.3%和61.1%。不同植被恢复群落生活型也有差异。侧柏+构树人工混交林群落高位芽植物占优势,而酸枣+牡荆灌丛和荩草+牡荆草灌丛则以地面芽植物所占比例较大。分析表明,多样性指数、均匀度指数和优势度指数均表现为侧柏+构树混交林>酸枣+牡荆灌丛>荩草+牡荆草灌丛,但物种丰富度表现为荩草+牡荆草灌丛>酸枣+牡荆灌丛>侧柏+构树混交林。Sörensen较高值出现在酸枣+牡荆灌丛与侧柏+构树混交林和荩草+牡荆草灌丛之间,侧柏+构树混交林与荩草+牡荆草灌丛Sörensen多样性值较低。研究结果表明,石灰岩山地独特的地貌特征和人工植被恢复对植物群落组成、多样性及其生活型组成产生重要影响。     

黄土丘陵区天然群落的植物组成、植物多样性及其与环境因子的关系

选择陕北黄土丘陵区不同立地条件下的4个典型群落,进行群落调查与土壤水分和养分的测定,探索天然群落自然恢复过程中群落的结构组成、植物多样性与环境因子的关系,为该地区的植被恢复提供指导。结果表明:植物群落组成主要集中在菊科、禾本科、豆科和蔷薇科,这4大科植物在该区具有较强的生态适应性;研究区天然群落组成较为简单;铁杆蒿(Artemisia sacrorum)在各立地均有分布,且重要值相对较大,为各个群落的优势种或者亚优势种;植物的生活型中多年生草本植物占优势,其次是半灌木,再其次是一、二年生草本植物,灌木植物所占的比例最少;相同坡向不同坡位的群落较为相似;不同立地条件下群落多样性指数的大小与各立地的水分条件关系密切。植被盖度、坡度、海拔高度和坡向对多样性产生影响,主要是通过直接影响土壤含水量实现的。土壤含水量是影响植物群落组成和多样性最为关键的生态因子,是黄土高原植被恢复和重建的关键性因子。     

半干旱黄土丘陵区微地形变化对人工柠条林草本分布的影响

本研究在典型半干旱黄土丘陵区龙滩小流域内,以水平阶整地方式栽植柠条（Caragana korshinskii）林为研究对象,调查不同坡位柠条林下水平阶内和阶间坡面草本群落组成及生物量,确定微地形及土壤环境变化对草本分布的影响及相对贡献率。结果表明：草本地上生物量及含水量均表现为水平阶内 > 阶间坡面,不同坡位水平阶内和阶间坡面草本组成的相异性为上坡位（75.2%） > 中坡位（60.0%） > 下坡位（50.7%）。pRDA排序表明：土壤含水量、微生境和坡位解释了35.8%的坡面草本群落变异,是影响草本群落分布的主要环境因子。相关分析表明：土壤含水量与长芒草（Stipa bungeana）的重要值呈显著负相关,与茵陈蒿（Artemisia capillaris）和束伞亚菊（Ajania parviflora）呈显著正相关;草本地上生物量与草本物种丰富度、长芒草等草本重要值呈显著负相关,与茵陈蒿等草本重要值呈显著正相关;下坡位草本地上生物量的降低促进了长芒草等地带性草本的恢复。综上所述,水平阶整地提高了林下草本地上生物量,降低了草本的物种丰富度,这在中、上坡位表现尤为明显。     

坡位及接种剂对苜蓿青贮品质及CNCPS蛋白组分的影响

分别以种植在上坡、中坡和下坡处的苜蓿品种中苜1号为原料,设置植物乳杆菌、复合乳酸菌剂两个接种剂处理,研究坡位和接种剂对苜蓿青贮品质及CNCPS蛋白组分的影响。结果表明,上坡处苜蓿青贮饲料的乳酸、粗蛋白质含量极显著高于另外两种坡位(P0.01),pH值、丁酸、中性洗涤纤维含量极显著低于另外两种坡位(P0.01)。接种剂的使用可以不同程度地降低苜蓿青贮饲料的pH值,减少氨态氮生成,抑制丁酸的产生,提高乳酸和干物质含量。植物乳杆菌可以降低上坡和中坡处的苜蓿青贮饲料的非蛋白氮含量(P0.05),提高中速降解蛋白含量(P0.05)。综上所述,上坡×植物乳杆菌处理的青贮品质较好,且可以保护更多的真蛋白不被降解。     

坡向对退化冷季型护坡草坪中植物种类及多样性的影响

以建成2年后的3个不同坡向的退化冷季型草坪中的植物群落为研究对象,通过测定群落组成、盖度、高度、密度及生物量,分析坡向对群落植物种类、重要值及物种多样性的影响。结果表明:坡向对退化草坪群落的植物组成有影响,不同坡向上植物种类差异明显,乡土植物入侵完全替代了多年生黑麦草(Lolium perenne L.)和早熟禾(Poa annua L.),荩草(Arthraxon hispidus)成为优势种;坡向对群落和草坪盖度、密度和生物量有显著影响(p0.05),对群落植物的重要值有明显影响;坡向对群落的Shannon-wiener多样性指数(H)和Pielou均匀度指数(J)有显著影响(p0.05),对Margalef丰富度指数(DM)和shimpson优势度指数(D)无显著影响(p0.05)。边坡草坪建植养护时,要考虑坡向对群落结构和群落稳定性的影响。     

青藏高原东缘异针茅草地群落组成及生产力研究

于2002-2004年对青藏高原东缘异针茅草地群落植被结构特征(植物种群优势度和群落物种数与生态优势度)、种群和群落生物量及其构成进行了系统研究。结果表明,异针茅草地植被组成复杂,主要由中旱生和耐寒中生植物组成,以异针茅为优势种,羊茅为亚优势种;草地中平均优势度大于0.150的植物有12种,伴生种种类多。草地植物种群和群落地上植物量月动态变化均呈先增加后降低的单峰曲线变化模式,生物量峰值出现于7-9月,种群生物量月动态存在植物种间分异。随利用年限的增加,草地群落植物组成逐渐由复杂群落向简单群落演替,群落生产力逐渐降低。     

青海湖东北岸草甸化草原植物群落特征及多样性分析

2008年对海北牧业气象站附近的草甸化草原植物群落特征及生物多样性进行了监测和研究。结果表明,研究区内群落的组成成分单一,植物种类比较贫乏,主要植物有23种,隶属9科,21 属,主要优势种为西北针茅（Stipa krylovii）;次优势种为矮嵩草(Kobresia humilis)、冷地早熟禾(Poa crymophila)等。北温带分布的属占优势植物群落,其生活型多年生植物占绝对优势,尤其是多年生非禾草类植物是群落的主要生活型;群落垂直结构不太明显,大体分3层;从物种多样性分析看,4条样线中,物种丰富度指数（R1、R2）、Shannon Wiener指数(H)、Simpson指数(D)及匀均度指数（E1、E2）变化差异不显著（P>0.05）,表现出基本一致的变化趋势。     

干热河谷冲沟沟头活跃度对植物群落结构的影响

为研究干热河谷冲沟沟头活跃程度对植被物种组成及其群落结构的影响,从而服务于冲沟植被恢复过程中最佳植被配置,采用典型样地法对元谋县内22条冲沟进行实地调查。研究结果表明:1)冲沟内植物种类随着沟头的稳定程度增加而增加,其中活跃型冲沟内植物12科28属共28种,半稳定型冲沟内植物16科29属共29种,稳定型冲沟内植物15科35属共37种;2)不同活跃程度的冲沟植被群落按生活型可分为3个层次,一是以扭黄茅为优势种,孔颖草、三芒草为次优种的草本层;二是以车桑子为优势种,银合欢为次优种的灌木层;三是以印楝为优势种,桉树为次优种的乔木层,但活跃型冲沟无乔木层;3)冲沟乔木层、灌木层和草本层的植被盖度均随着冲沟沟头稳定性的增加而增加,表现为稳定型冲沟>半稳定型冲沟>活跃型冲沟;4)不同活跃程度的冲沟沟头群落结构均以多年生草本和灌木为主,乔木种类较少,优势物种相同且占有显著地位,但随着冲沟沟头的逐渐稳定,乔木数量和多样性均逐渐增加;5)活跃型冲沟、半稳定型冲沟、稳定型冲沟之间草本层、灌木层、乔木层的植物群落相似性分别表现为中等相似、极为相似、极度不相似,且冲沟不同恢复阶段灌木层中植物有趋同演化的趋势,共有程度很高,冲沟沟头活跃程度对灌木层植物群落功能造成的影响小于对草本层和乔木层植物群落。总体而言,不同活跃程度的冲沟沟头植被群落结构之间具有显著差异,研究结果将为冲沟生态恢复提供科学依据。     

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 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.

     

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%).     

Scrapie in goats in Cyprus

Ovine scrapie was first recorded in Cyprus in 1985. Subsequently four dairy goats kept in two mixed flocks with affected sheep developed characteristic clinical signs similar to those seen in sheep. Fifteen goats from the two flocks were examined histologically and neurological lesions consistent with a diagnosis of scrapie were found in the four animals and in three others which had subsequently developed early neurological signs. These lesions were similar to those of naturally-affected sheep although neuronal degeneration and vacuolation were more severe in some cases.     

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 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%).