人类活动和滩涂变迁对苏北沿海地区獐分布的影响

结合查阅历史资料,访问当地群众和实地调查等方法,对獐在江苏沿海的历史分布以及人类活动和滩涂变迁对其分布的影响进行了研究。历史上,江苏沿海地区有大量适合獐生存的草滩,尤其是1128年黄河夺淮后,使江苏沿海的滩涂迅速淤涨,形成了大面积的适合獐生存的草滩。1855年黄河北归以后,滩涂淤涨减少,本世纪初开始,随着人类对滩涂围垦和开发的强度日益增加,獐分布面积日益减少。近20年来,獐的分布区开始破碎。目前,江苏沿海獐的分布已分裂为4个面积不足100km2的小区,如没有有效的措施保护獐的栖息地,该地区獐的灭绝将不可避免。     

人类活动和滩涂变迁对沿海地区獐分布的影响

结合查阅历史资料,访问当地群众和实地调查等方法,对獐在江苏沿海的历史分布对及人类活动和滩涂变迁对其分布的影响进行了研究。历史上,江苏沿海地区有大量适合獐生成的草滩,尤其是１１２８年黄河夺淮后,使江苏沿海的滩涂迅速淤涨,形成了大面积的适合生存的草滩。１８５５年黄河北归以后滩涂淤涨减少,本世纪初开始,随着人类对滩涂围垦和开发的强度日益增加,獐分布面积日益减少。近２０年来,獐的分布区开始破碎,目前,江苏     

江苏盐城自然保护区獐栖息地的质量评价

本研究通过1999 年3 月至2000 年11 月期间的实地调查,利用地理信息系统(GIS)对江苏省盐城自然保护区及周边地区獐在产仔前期、产仔期以及产仔后期栖息地适宜性进行了评价,并对理想状况下獐的潜在栖息地和实际栖息地的范围及分布进行了比较。理想状况下3 个不同时期獐的最适宜栖息地面积分别为361.0 km² 、267. 5 km² 和338. 5 km², 主要分布在保护区核心区、东台市琼港镇南的新东乡滩涂;而实际在各个时期獐的最适宜栖息地面积只有44.75 km² 、36.00 km² 和54. 50 km² ,仅为潜在栖息地的1/7 左右。通过比较獐的潜在栖息地与实际栖息地的综合适宜性指数发现,整个研究地区适合獐生存的栖息地非常少,最适宜栖息地的面积不到总面积的1%,而不适宜的栖息地面积却达到40%,其余大部分均是次适宜的栖息地。由于獐的栖息地受到道路和居民等人为活动的影响,导致大量适宜栖息地丧失。为了有效地保护盐城保护区及周边地区的獐种群,建议减少对滩涂的各种开发活动,保护现有的适宜栖息地,引导当地居民合理利用滩涂资源。     

江苏沿海滩涂泌盐植物——獐毛的形态特征及经济性状

獐毛是江苏沿海滩涂分布的一种多年生草本植物和盐渍土指示植物,具有很强的抗盐、抗旱能力。獐毛也是极具潜力的、可贵的抗性基因库的重要物种。同时,还具有很高的药用和生态价值。     

基于红外相机技术的秋冬季城市森林公园獐的活动节律分析和生境选择

獐(Hydropotes inermis)是东亚特有种,其自然分布范围仅限于中国与朝鲜半岛,过度的人为干扰造成獐种群数量锐减和分布空间破碎化,形成孤立的岛屿化分布。为了解獐在岛屿化城市森林公园中的生存状况,我们利用红外相机技术在南京老山森林公园及周边对秋冬季獐进行监测,分析了其活动节律和生境选择偏好。2020年10月—2021年3月,共设置了35个相机位点,期间共拍摄獐的有效照片233张,有效探测次数245次,相对丰富度指数为10.7。獐的日活动节律呈双峰模式,分别在04:00—06:00和18:00—20:00达到高峰;獐活动节律存在月间变化,月活动高峰为12月;不同的温度区间对獐的活动有显著影响,环境温度4～6℃时獐的活动强度最大;广义线性模型结果表明,獐对常绿落叶阔叶林、优势灌丛高度≥120 cm的生境有显著偏好,且相对丰富度指数与距最近路口距离呈正相关,与干扰指数呈负相关。与其他大面积的自然保护区和水网地域相比,城市森林公园中的獐虽呈现出典型的晨昏活动模式但无明显的夜行性活动特点,对距最近水源距离呈随机选择。老山地区獐受干扰强度较大。因此,合理管控老山森林公园及周边地区的人类活...     

基于MaxEnt模拟人类活动与环境因子对青藏高原特有植物祁连獐牙菜潜在分布的影响

以青藏高原特有植物祁连獐牙菜(Swertia przewalskii Pissjauk.)为材料,基于该物种18个种群分布点及8个生物气候变量、海拔变量以及人类活动强度变量,运用最大熵模型(Max Ent)和ArcGIS技术分别构建当前气候情景下及人类活动影响下祁连獐牙菜的适宜生境预测模型,研究人类活动及自然环境变量对祁连獐牙菜空间分布的影响。结果显示,人类活动影响下的训练集和测试集的AUC值均小于无人类活动干扰的AUC值,人类活动与祁连獐牙菜分布呈负相关。限制祁连獐牙菜分布的主要变量为海拔、等温性、人类活动足迹指数及平均温度日较差。当前气候情景下祁连獐牙菜的最适宜生境占祁连山国家公园青海片区总面积的36.6%,有利于该物种的保护和恢复,而位于门源县和祁连县保护区内一般控制区的潜在生境受到人为干扰的可能性较大,应加强关注和保护。     

互花米草入侵对大型底栖动物群落垂直结构的影响

2012年8月,在浙江省玉环县漩门湾国家湿地公园,利用自制分层采样器,以5 cm为单位对0—25 cm泥层进行分层取样,研究潮间带互花米草滩涂和自然滩涂两种生境中大型底栖动物的垂直分布情况,以及互花米草入侵对大型底栖动物垂直结构的影响。两种生境中共获得大型底栖动物40种,其中软体动物18种,甲壳动物13种,环节动物4种,其他类群5种。在自然滩涂生境中获得的物种数为30种,互花米草生境为31种,两种生境的共有种有21种。互花米草和自然滩涂生境平均栖息密度分别为222.6株/m2和1052.8株/m2。研究结果表明:(1)大型底栖动物主要栖息在0—10 cm泥层深度;(2)大型底栖动物群落沿泥层深度存在分层分布现象;(3)互花米草入侵缩短了底栖动物的垂直分布距离,但对其主要栖息深度影响不大;(4)互花米草入侵改变了原来生境特征,导致大型底栖动物的群落结构发生变化。     

长江口及杭州湾北部滩涂的生物群落特征分析

滩涂是指潮间带新沉积的滩地,是海岸带生态研究的主要组成部分,滩涂生境最显著的特点是潮汐的周期性变动,使滩涂的水界和气界呈规律性地交替。在这个特定生境中生活的各种生物种群,相互松散地结合,形成独特的潮间带滩涂群落。其结构,分布特点,优势种及相对丰富度等都与滩涂的潮汐节律、底质粒径、温度、盐度、光照强度等环境条件相关联。本文根据对长江口,杭州湾北部的滩涂生     

舟山群岛獐的分布

1999 年7 月至2000 年6 月采用访问和样线法对浙江舟山群岛25 个岛上的獐的分布进行调查。结果显示獐在该地区主要分布在北纬30°26′以南, 东经122°24′以西, 且集中在西南诸岛上。较大岛屿獐的分布比例较高, 10 km²以上的岛屿81.25 %有獐分布。并且其周围小岛獐的分布比例也较高。所调查的5 个距离舟山本岛3 km范围内的小岛均有獐分布。獐所分布的岛屿随着离大陆和本岛距离的增加而减少。獐主要栖息在山丘上, 但夜里常到农田觅食。21.47 %有人居住岛上有獐分布。对獐分布影响较大的因素是离本岛和大陆的距离及岛屿面积; 其次是人类活动, 主要是偷猎; 淡水水源影响不大; 分布与岛屿形状无关。獐可以在岛屿之间迁游, 从而影响分布。獐在舟山地区可能是原有分布的, 几次地质变化可能对其产生一定影响。     

基于MaxEnt模型预测白琵鹭在中国东北地区的适宜分布区

白琵鹭(Platalea leucorodia)为我国国家Ⅱ级保护野生动物,目前已知的白琵鹭繁殖生境分布较为破碎。近年来,在全球气候变化的背景下,人类对地下水超采、湿地开垦等致使作为白琵鹭主要繁殖地的我国东北地区湿地面积缩减,因此有必要制定科学的保护计划去减轻东北地区环境变化导致的白琵鹭生境破碎化。本研究的主要目的是运用MaxEnt模型与GIS空间技术对东北地区白琵鹭的生境适宜性及其主要影响因子进行分析。受试者工作特征曲线下面积(训练AUC和测试AUC)分别为0.918和0.945,显示了模型预测能力较高,适合白琵鹭的潜在生境预测。研究发现:影响白琵鹭繁殖生境分布的主要环境因子是海拔(36.8%)和植被覆盖度(32.6%),其次是等温性(11.5%)、距湖泊距离(8.6%)和最干季降水量(4.0%),影响较少的是距道路距离(2.7%)、最湿月降水量(2.4%)、距居民地距离(0.8%)、土地利用类型(0.4%)和距河流距离(0.2%)。白琵鹭在东北地区的适宜栖息地集中在低海拔、气候适宜和离水源较近的地方。获得了适宜白琵鹭生境的自然保护地(自然保护区、湿地公园)分布。本研究为白琵鹭的保护提供了科学信息,并为其栖息地管理提出了相关建议。     

Action of volatile substances liberated from couch grass

A study was made of the action of volatile substances liberated from the rhizome of couch grass on wheat seedlings. The experiments were made in a closed atmosphere in glass vessels with continual removal of expired CO₂ and the addition of O₂. Volatile substances liberated from couch grass produced numerous morphological and physiological changes in wheat seedlings. They caused retarding of the growth of overground parts and roots, the excessive formation of root hairs, curling of the roots and bending of the coleoptiles. The respiratory rate was higher in the leaves and roots of the experimental wheat seedlings than in the controls. The changes observed were similar to those produced by hydrocarbons of the ethylene series, which are well documented in the literature.     

SLUG DAMAGE AND NUMBERS OF SLUGS IN OILSEED RAPE BORDERING ON GRASS STRIPS

In 1995, slug damage and numbers of slugs were estimated intwo grass strips and adjacent rape fields. Investigations beganas soon as rape seedlings emerged and lasted for five weeks.Slug damage to rape plants 1 m from the grass strips was significantlyhigher than at greater distances from the strips. Derocerasreticulatum was the most abundant slug species recorded in bothgrass strips and adjacent rape fields. Arion lusitanicus andArion fasciatus were much less abundant than D. reticulatum.In one field, D. reticulatum declined steadily with increasingdistance from the grass strips and therefore appeared to havecaused the majority of severe damage to rape plants close tothe strips. This finding was surprising because until now severeslug damage in oilseed rape beside semi-natural habitats hasbeen observed only where A. lusitanicus was abundant. (Received 12 November 1997; accepted 26 January 1998)     

A new type of cereal lectin from leaves of couch grass (Agropyrum repens)

Extracts from couch grass (Agropyrum repens) leaves contain relatively high lectin concentrations. Preliminary experiments with crude extracts indicated that the leaf lectin differs from the embryo lectin of the same species and other Gramineae embryo lectins with respect to its sugar and blood group specificity, and serological properties. A comparison of the biochemical, physicochemical and biological properties of purified lectins from couch grass leaves and embryos, and wheat germ agglutinin revealed that the leaf lectin has the same molecular structure as the embryo lectins. It is a dimer composed of two identical subunits, which, however, are slightly larger than embryo lectin subunits. Structural differences between both couch grass lectins were further inferred from in vitro subunit exchange experiments and serological analyses. Whereas the embryo lectin readily forms heterodimers with embryo lectins from other cereal species and also is serologically indistinguishable from them, the leaf lectin does not exchange subunits with the same embryo lectins and is serologically different. In addition, couch grass leaf lectin exhibits specificity for N-acetylgalactosamine and agglutinates preferentially blood-group-A erythrocytes whereas the embryo lectin is not inhibited by N-acetylgalactosamine and exhibits no blood-group specificity. It was observed also that the lectin content of couch grass leaves varies enormously during the seasons.     

OBSERVATIONS AND EXPERIMENTS ON THE HESSIAN FLY (MAYETIOLA DESTRUCTOR SAY)

Experiments showed that a stem midge collected locally on couch grass ( Agropyron repens ) and similar midges collected on wheat, barley and rye were of the same species, i. e. the hessian fly, Mayetiola destructor Say. There were three main flights per year, with some overlapping of the generations. In experiments, Aegilops ovata, Triticum compactum, T. dicoccoides, T. durum, T. spelta and T. turgidum were successfully used as host plants besides wheat, barley, rye and couch grass. Individual female midges when moved from plant to plant gave rise to families on the different host plants; similarly, succeeding generations of midges were able to breed on various host plants other than those from which they themselves were reared. Oviposition also took place on plants on which larvae failed to establish themselves.
Wheat seemed more favourable for the hessian fly than couch grass, and more midges were reared from young plants than from mature ones.
Unisexual families occurred in about half the experiments. The following parasites were bred: Trichacis didas Walker, Eupteromalus? hemipterus Walker, Platygaster sp., Chrysocharis sp. and Tetrastichus sp.     

三峡库区花岗岩坡耕地不同种植方式下水土流失定位研究

对三峡库区花岗岩坡耕地不同种植方式下水土流失规律的定位研究表明,库区雨季主要集中在5～8月,降雨量约占全年总降雨量的60%以上;此期间的土壤侵蚀量也占全年总侵蚀量的60%以上,其中6、7月土壤侵蚀量约占全年的1/2.不同种植方式下地面覆盖率差异较大,三熟制下或与多年生植物(牧草、黄花菜)间作时地面的覆盖率明显大于两熟制,夏季作物为花生时雨季的地面覆盖高于夏作为红薯,其土壤及养分流失量亦相对较低.不同种植方式下土壤及养分流失的大小顺序为油(麦)红薯>油菜(小麦)玉米红薯>油菜(小麦)玉米花生>油菜(小麦)金荞麦花生,油菜(小麦)黄花花生.研究结果还表明,在良好的种植与管理方式下,坡耕地土壤流失量仍可被控制在允许范围内.     

小麦间作大蒜或油菜对麦长管蚜及其主要天敌种群动态的影响

麦长管蚜是我国冬小麦产区的重要害虫.试验探索了不同间作方式对麦长管蚜及其主要天敌的影响.结果表明,在调查期内,麦-油(油菜)间作田和麦-蒜(大蒜)间作田中麦长管蚜无翅蚜的种群密度多显著低于单作田;麦-油间作田中有较高的瓢虫种群密度和瓢蚜比;5月2日前,麦-油间作田中蚜茧蜂的种群密度高于单作田和麦-蒜间作田;5月5日后,麦-油间作田的僵蚜率和蜂/蚜比也显著高于单作田和麦-蒜间作田;麦-蒜间作田有翅蚜的种群数量较高,但瓢虫和蚜茧蜂的种群数量无明显变化.麦-油间作和麦-蒜间作均能对麦田中麦长管蚜起到较好的控制作用.     

Host plant choice and location by larvae of the wheat bulb fly (Delia coarctata)

Wheat bulb fly (Delia coarctata Fallen, Diptera: Anthomyiidae) is an important pest of winter wheat in the eastern half of the UK, and in northern and eastern Europe. The larvae must find a host plant and invade a tiller soon after hatching in late January. Chemical controls are costly and weather conditions may reduce their efficacy or prevent their application. Post‐emergence control relies on organophosphate insecticides, which may soon be withdrawn due to concerns about their negative health and environmental effects. Winter wheat (Triticum aestivum L.) is the preferred cereal host, but other winter cereals and related grasses may also be attacked, while oats (Avena spp.) are shunned. In choice test bioassays, neonate larvae chose couch grass (Elytrigia repens (L.) Nevski syn. Elymus repens (L.) Gould, Agropyearon repens (L.) Beauv.) seedlings and exudates over wheat seedlings and exudates, and exhibited geotaxis and negative phototaxis. Analysis of larval trails in choice test bioassays of seedling exudates showed that couch exudates are more attractive than wheat exudates, and that wheat exudates are more arrestant than couch exudates. This suggests that infochemicals isolated from couch, wheat, and oats could be used in wheat bulb fly control; possible delivery mechanisms are discussed. These findings, previous research, and a comparison of the phenologies and geographical distributions of D. coarctata and its hosts suggest that E. repens is the natural host of D. coarctata.     

High‐resolution spatial modelling of greenhouse gas emissions from land‐use change to energy crops in the United Kingdom

We implemented a spatial application of a previously evaluated model of soil GHG emissions, ECOSSE, in the United Kingdom to examine the impacts to 2050 of land‐use transitions from existing land use, rotational cropland, permanent grassland or woodland, to six bioenergy crops; three ‘first‐generation’ energy crops: oilseed rape, wheat and sugar beet, and three ‘second‐generation’ energy crops: Miscanthus, short rotation coppice willow (SRC) and short rotation forestry poplar (SRF). Conversion of rotational crops to Miscanthus, SRC and SRF and conversion of permanent grass to SRF show beneficial changes in soil GHG balance over a significant area. Conversion of permanent grass to Miscanthus, permanent grass to SRF and forest to SRF shows detrimental changes in soil GHG balance over a significant area. Conversion of permanent grass to wheat, oilseed rape, sugar beet and SRC and all conversions from forest show large detrimental changes in soil GHG balance over most of the United Kingdom, largely due to moving from uncultivated soil to regular cultivation. Differences in net GHG emissions between climate scenarios to 2050 were not significant. Overall, SRF offers the greatest beneficial impact on soil GHG balance. These results provide one criterion for selection of bioenergy crops and do not consider GHG emission increases/decreases resulting from displaced food production, bio‐physical factors (e.g. the energy density of the crop) and socio‐economic factors (e.g. expenditure on harvesting equipment). Given that the soil GHG balance is dominated by change in soil organic carbon (SOC) with the difference among Miscanthus, SRC and SRF largely determined by yield, a target for management of perennial energy crops is to achieve the best possible yield using the most appropriate energy crop and cultivar for the local situation.     

安徽沿江圩丘农区夏收作物田杂草群落分布规律的研究

作者创用了七级目测调查取样,进行数量分析的方法,对夏收作物田杂草群落进行分类研究,揭示了安徽沿江圩丘农区夏收作物田杂草群落的分布规律主要受土壤类型和轮作制度制约。看麦娘杂草群落分布于水稻土田,猪殃殃,野燕麦杂草群落分布于丘岗区旱地,卷耳、婆婆纳杂草群落分布于灰潮土旱地。首次提出综合草害指数,用以评定杂草群落类型中每种杂草的危害性,从而,提出了不同土壤类型和轮作制度的田块中恶性杂草的定量化指标与防除策略。     

STUDIES OF FLUCTUATIONS IN INSECT POPULATIONS XII. FURTHER EVIDENCE OF PROLONGED LARVAL LIFE IN THE WHEAT-BLOSSOM MIDGES

Contarinia tritici emerges the same year as the larvae are in the wheat ears and up to 3 years later. Its parasites emerge up to 2 years after the larvae are in the wheat ears, but never the same year. This indicates that the supernumerary generation of C. tritici that occurs on couch grass in August and September may be expected to be free from parasites and so constitutes a dangerous source of replenishment of the pest.
Emergence of Sitodiplosis mosellana can take place after the larvae have been in the soil up to twelve winters. Most of any one year's larvae do not necessarily emerge as midges after one winter, although usually this is so. Any one year's flight is probably a composite one derived from several previous generations of this one-generation-a-year gall midge.