Landscape and habitat factors affecting cabot's tragopan Tragopan caboti occurrence in habitat fragments.     

Wen-hong Deng  Guang-mei Zheng 《Biological conservation》2004,117(1):25-32

Cabot's tragopan Tragopan caboti is an endemic and endangered pheasant of the lower montane forests of southeastern China. The typical habitats of the tragopan have been seriously fragmented because of forest management for timber production and farmland reclamation in recent years. The effects of the fragment size and isolation on the distribution of the cabot's tragopan were studied in Wuyanling Natural Reserve. Thirty one habitat fragments (2.5-48.5 ha) surrounded by non-habitat sapling coniferous forests, in an intensively managed forested landscape, were surveyed over four seasons for the occurrence of cabot's tragopan. Five of the 31 fragments were occupied in all four seasons and nine were not occupied. Both landscape and habitat factors affected the occurrence of cabot's tragopan, with landscape factors having the greatest effect. Large and less isolated habitat fragments containing a larger amount of the tree Daphniphyllum macropodum were occupied significantly more often than small, isolated fragments. The appearance of cabot's tragopan in the habitat fragments was best explained by the size of the fragments, the distance to the nearest suitable habitat and the amount of macropdous daphniphyllum trees. Our results could be used to improve the management of the forests where Cabot's tragopan occurs in southeastern China.  相似文献   

承德避暑山庄杜梨瘿螨发生规律研究     

刘海光 《安徽农业科学》2009,37(16):7540-7541

[目的]研究杜梨瘿螨在杜梨树上的自然发生规律,并观察评估杜梨瘿螨对其他果树、蔬菜为害的可能性。[方法]野外调查结合室内观察了解杜梨瘿螨在杜梨树上的自然发生规律 室内人工接虫饲育观察杜梨瘿螨对其他多种果树、蔬菜为害的可能性。[结果]基本摸清了杜梨瘿螨在杜梨树上的自然发生规律,杜梨瘿螨在承德一年发生2代,以成螨于杜梨芽鳞内越冬,春季4月中旬在杜梨树初展叶时,越冬螨虫开始出蛰活动 7月下旬叶面上的虫瘿数达到最高峰,8月上旬后螨虫开始蛰伏越冬。接虫饲育试验表明,杜梨瘿螨仅在桃、山楂叶片上能存活较长时间,但不能形成虫瘿,在所有的供试果树和蔬菜上均不能最终成活。[结论]杜梨瘿螨活动为害期集中在4~7月,具有生态脆弱性,属单食性害虫,只能在杜梨树上形成虫瘿,对供试的多种植物不构成危害。  相似文献   

从江县柑桔矢尖蚧发生特点及主要因子分析     

石安鸠 《贵州林业科技》2006,34(2):32-34

对近几年从江地区柑桔矢尖蚧(Uaspis yanonensis(kuwana))发生危害的情况和特点进行了总结和分析,指出管理不善、不易抓住防治时机、虫源和天敌是影响柑桔矢尖蚧发生的主要因子,并提出了相应的防治对策。  相似文献   

中国果树类病毒的发生及其研究进展(英文)   总被引：4，自引：0，他引：4  

王国平  洪霓  Ahmed Hadidi 《果树学报》2005,22(1):51-54,F003

概述了在中国发生且己鉴定明确的5种果树类病毒,即苹果绣果类病毒(Apple scar skin viroid,ASSVd)、梨泡状溃疡类病毒(Pear blister canker viroid,PBCVd)、葡萄黄斑类病毒-1(Grapevine yellow speckle viroid-1,GYSVd-1)、柑橘裂皮类病毒(Citrus exocortis viroid,CEVd)和桃潜隐花叶类病毒(Peachlatent mosaic viroid,PLMVd)的研究进展,包括病害的首次发现、症状特征、发病规律、检测方法与防治对策以及这些类病毒的生物学与分子生物学特性。  相似文献   

Cultivation Influences on Soil Organic Carbon Associated with Texture in Seasonally Frozen Zones     

Xiao PU  ;Jing XIE  ;Hongguang CHENG  ;Shengtian YANG  ;Shuangbao WANG 《农业科学与技术》2014,(7):1147-1151

[Objective] This study aimed to examine indicative roles of texture representing soil organic carbon presence and variability subsequent to cultivation under cold temperate climates with seasonal freeze-thaw events.[Method] Three chronosequences were selected for paired comparisons.Soil samples were collected at six depths with a 10 cm increment.Analysis of variance with general linear model and regression was performed for statistical analysis.[Result] In seasonally frozen soils where fragmentation of macroaggregates was stimulated,soil organic carbon level was positively associated with clay ＋ silt proportion due to a wider textural range,better than sole clay content.Exponential function better fitted the experimental data to present progressively increased effectiveness of clay ＋ silt content in maintaining carbon.Clay content explained 12％-41％ and 14％-43％ of variation via linear and exponential functions,respectively.Accordingly,clay ＋ silt content explained 47％-65％ and 46％-70％.[Conclusion] Texture reflected soil organic carbon occurrence as consequences of reclamation.For seasonally frozen soils with wider textural ranges,it is robust to adapt clay ＋ silt content as dependent variable and exponential function.The generated algorithms provided an available pathway to estimate soil organic carbon losses following cultivation and to evaluate soil fertility.  相似文献   

通辽地区紫花苜蓿田杂草种类及发生规律的调查研究     

安瑞军王思源  侯瑞阔 《牧草与饲料》2007,1(2):36-38

通过对紫花苜蓿田杂草种类及发生规律的调查研究，表明通辽地区紫花苜蓿田有13科31种杂草，以一年生杂草为主；优势杂草藜、酸模叶蓼、打碗花、稗、反枝苋等呈集群分布；主要杂草发生时间在紫花苜蓿播种后10d左右进入出苗高峰期；一年生杂草大量发生时间在5～6月份，二年生和多年生杂草易常年发生；以禾本科稗草，阔叶类杂草藜、反枝苋、酸模叶蓼、打碗花发生最为普遍，危害严重。  相似文献   

关于全概率公式及其应用的研究     

戴维纪  贾振声 《山西农业大学学报(自然科学版)》1998,18(1):75-77

本文对全概率公式的直观背景及应用公式的关键作了分析。  相似文献   

如皋市双条杉天牛的发生及综合防治   总被引：3，自引：0，他引：3  

沈继珍  高国兴  丁海琴  陈建华  许小林 《江苏林业科技》2001,28(4):34-36

对双条杉天牛从形态特征、生物学特性、寄主范围、危害率等方面进行了调查，并提出了防治双条杉天牛的对策和措施。  相似文献   

萧氏松茎象发生现状与防控对策     

柴守权  尤德康  赫传杰  王志勇  李上福 《林业科技》2007,32(6):26-28

阐述了我国萧氏松茎象(Hylobilelus ×iaoi)的发生与危害现状,分析了主要发生原因,提出了包括治理思路、工程治理、机制创新、预防措施、调控措施和除治措施等方面的防控对策.  相似文献   

日本龟蜡蚧在枣树上的发生与危害   总被引：3，自引：0，他引：3  

李新岗  黄君伟 《陕西林业科技》1997,(3):51-54

１９９６年８月￣１９９７年６月，在陕西大荔县八鱼乡西营村和蒲支县平路庙乡直杜村调查了日本龟蜡蚧在枣树上的分布与危害。结果表明，单叶幼虫数随枣树受害程度的增加而增加，单果重随枣树爱害程度的增加而减少，越冬雌虫的危害造成每股的抽吊数减少，吊长显著变短，每吊的刺树数减少，幼虫和雌成虫在树冠上的分布是阳面（南面）大于阴面（北面），其中树冠中部虫量分布的最多。  相似文献