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71.
1. The freshwater crayfish Cherax dispar (Decapoda: Parastacidae) inhabits coastal regions and islands of South East Queensland, Australia. We hypothesised that populations of C. dispar on different islands would be more genetically divergent from each other than populations from different drainages within the same island or on the mainland. 2. Phylogenetic and phylogeographic analyses were conducted on two mitochondrial genes (cytochrome oxidase subunit I & 16S ribosomal DNA) and one nuclear gene (Internal Transcribed Spacer region 2). Phylogeographic patterns were compared with those for other freshwater organisms in the area. 3. Deep genetic divergences were found within C. dispar, including four highly divergent (up to 20%) clades. The geographic distribution of each of the clades revealed strong latitudinal structuring along the coast rather than structuring among the islands. The high genetic divergence observed among the C. dispar clades was estimated to have pre‐dated island formation and may represent ancient river drainage patterns. 4. A restricted distribution was observed for the most divergent clade, which was discovered only on two of the sand islands (North Stradbroke Island and Moreton Island). Furthermore, strong phylogeographic structuring was observed within this clade on North Stradbroke Island, where no haplotypes were shared between samples from opposite sides of the island. This low connectivity within the island supports the idea that C. dispar rarely disperse terrestrially (i.e. across watersheds).  相似文献   
72.
长期施肥对黄淮海平原农田中小型土壤节肢动物的影响   总被引:4,自引:1,他引:3  
在2008年9月和2009年2月,采用改良干漏斗方法(Modified Tullgren)对黄淮海地区长期定位施肥试验下中小型土壤节肢动物进行调查。试验包括氮磷钾(NPK)、氮磷(NP)、氮钾(NK)、磷钾(PK)、有机肥(OM)、1∶1化学氮肥与有机氮肥(OMNPK)和不施肥(CK)7个处理。结果表明:OM和OMNPK处理有利于提高土壤动物丰富度和多样性;NK处理不利于土壤动物的生存和发展,缺磷影响了土壤动物数量的增长;从优势类群弹尾目和蜱螨目来看,OM和OMNPK处理对弹尾目等节跳科、棘跳科和球角跳科的生长有利,而圆跳科在NPK处理下具有更高的数量;OMNPK处理对蜱螨目中气门亚目有显著的正效应,对前气门亚目和甲螨亚目也有一定的正向作用;氮肥对弹尾目没有表现出正相关关系,但在一定程度上增加了蜱螨目的数量。  相似文献   
73.
1995~2003年调查并整理分析青海湟水流域的蝶类,有9科52属80种,其中凤蝶科1属2种,绢蝶科1属6种,粉蝶科8属22种,斑蝶科1属1种,眼蝶科12属13种,蛱蝶科15属18种,蚬蝶科1属3种,灰蝶科9属10种,弄蝶科4属5种.以古北界为主,青藏区最为丰富.  相似文献   
74.
The migrations of Gymnocephalus baloni Balon's ruffe into the side branch of the Danube at Schönbühel were restricted to the spawning season between the end of April and mid-June. The main environmental factor correlating with the immigration is assumed to be water temperature. Water level changes influence emigration.  相似文献   
75.
长江口海三棱藨草带生长季大型底栖动物群落变化特征   总被引:4,自引:0,他引:4  
2006年4—11月对长江口崇明东滩海三棱藨草(Scirpus mariqueter)带大型底栖动物群落进行了定位调查研究。每月1次采用样方法对大型底栖动物和植被进行同步取样;在鉴定、计数和生物量(干重)测定分析的基础上,进行了多样性测度以及聚类、排序等统计分析。研究结果表明,生长季内海三棱藨草带大型底栖动物的多度和生物量整体呈上升趋势,但是月间存在一定波动变化,9月份多度最高,平均为1536ind/m2,10月份生物量(干重)最高,平均为21.60g/m2;不同月份优势类群组成、多度及生物量特征存在明显差异,瓣鳃类仅在部分时段表现出优势特征。物种数整体呈V字型变化特征,在8月份达到最低值。由于种间个体数量分布的变化滞后于整体物种数的变化,Shannon-Wiener多样性指数、Pielou均匀度指数的峰谷变化滞后于物种数变化,即物种数在5月份达到最低,而多样性及均匀度指数在6月份达到最小值。海三棱藨草带大型底栖动物群落的月间变化特征,在很大程度上是水文(包括水动力条件)以及植被等因素综合作用的结果,但在不同时期主导因子或者不同因子协同作用不同。它们的直接影响是导致底栖动物种类组成、多度变化,进而改变整体生物量和多样性特征。  相似文献   
76.
Restoring ecological balance to the British mammal fauna   总被引:1,自引:0,他引:1  
  • 1 The mammal fauna of the British Isles has seen major perturbations since the end of the last ice age, some natural and some anthropogenic. Today, 61 species of terrestrial mammals breed in the British Isles, but only 39 of them are native species, the rest have been introduced. Furthermore, 19 native species have disappeared from the fauna including all the large predators, lynx Lynx lynx, wolf Canis lupus and brown bear Ursus arctos.
  • 2 Inevitably, these changes in species composition have been accompanied by major changes in community function including changes in patterns of energy flow through the mammalian community. For example, a high percentage of all the energy now flows through the introduced rabbit Oryctolagus cuniculus population and red deer Cervus elaphus, which, in the absence of natural predators, are living at extremely high densities.
  • 3 Could the reintroduction of species help to reverse such changes in community structure and function? The successful return to the wild of species such as the Arabian oryx Oryx leucoryx and beaver Castor fiber has shown that reintroductions are certainly possible. However, the impact on community function of returned species is more difficult to evaluate.
  • 4 This question is addressed in relation to the consequences for deer populations of any possible reintroduction of the wolf to Scotland. Based on what we know of wolves elsewhere, predictions are made about the likely demography and patterns of killing behaviour of introduced wolves. These values are then used to parameterize a Leslie matrix simulation of the impact of wolves on contemporary populations of red deer in Scotland. The simulations suggest very strongly that wolves are very unlikely to have any significant impact on the high‐density populations of deer now living in the Scottish landscape.
  相似文献   
77.
This study assesses the impact of a changing climate on fish fauna by comparing the past mean state of fish assemblage to a possible future mean state. It is based on (1) local scale observations along an Inner-Alpine river called Mur, (2) an IPCC emission scenario (IS92a), implemented by atmosphere-ocean global circulation model (AOGCM) ECHAM4/OPYC3, and (3) a model-chain that links climate research to hydrobiology. The Mur River is still in a near-natural condition and water temperature in summer is the most important aquatic ecological constraint for fish distribution. The methodological strategy is (1) to use downscaled air temperature and precipitation scenarios for the first half of the twenty-first century, (2) to establish a model that simulates water temperature by means of air temperature and flow rate in order to generate water temperature scenarios, and (3) to evaluate the impact on fish communities using an ecological model that is driven by water temperature. This methodology links the response of fish fauna to an IPCC emission scenario and is to our knowledge an unprecedented approach. The downscaled IS92a scenarios show increased mean air temperatures during the whole year and increased precipitation totals during summer, but reduced totals for the rest of the annual cycle. These changes result in scenarios of increased water temperatures, an altered annual cycle of flow rate, and, in turn, a 70 m displacement in elevation of fish communities towards the river’s head. This would enhance stress on species that rely on low water temperatures and coerce cyprinid species into advancing against retreating salmonids. Hyporhithral river sectors would turn into epipotamal sectors. Grayling (Thymallus thymallus) and Danube salmon (Hucho hucho), presently characteristic for the Mur River, would be superceded by other species. Native brown trout (Salmo trutta), already now under pressure of competition, may be at risk of losing its habitat in favour of invaders like the exotic rainbow trout (Oncorhynchus mykiss), which are better adapted to higher water temperatures. Projected changes in fish communities suggest an adverse influence on salmonid sport fishing and a loss in its high economic value.  相似文献   
78.
徐宁  魏刚 《四川动物》2007,26(2):350-353
在柏菁保护区共采到两栖动物标本267号,经整理鉴定隶属1目、6科、6属、13种。该区两栖动物垂直分布划为3个带:(1)海拔600.1000m为低山河谷农田两栖类带,本带两栖类6种,占总种数的46.15%;(2)海拔1000.1750m为中山台地农田针叶林两栖类带,有两栖类11种,占总种数的84.62%;(3)海拔1750~2200m为中山高原森林两栖类带,仅有1种。柏箐地区在动物地理区划上属于华中区,但两栖类以华中及华南区种为主。还讨论了中华蟾蜍和华西蟾蜍的分类地位。  相似文献   
79.
2003~2005年对四川海子山自然保护区兽类资源进行了3次野外调查,结合历史文献确认保护区有兽类64种。其中东洋界种类有32种,古北界种类30种,广布种2种。保护区兽类有11种分布型,有国家Ⅰ级重点保护动物6种,Ⅱ级保护动物20种。有我国特有或主要分布于我国的兽类31种。保护区兽类的特点是大型兽类如白唇鹿、水鹿、林麝、马麝、黑熊、马熊等资源非常丰富,种群数量大、密度高,具有很高的保护价值;小型兽类资源丰富,有较多的珍稀物种。  相似文献   
80.
从2007年4月到9月,对八大公山国家自然保护区蛾类昆虫进行了初步调查,共获得蛾类标本4000余号。与湖南农业大学昆虫学教研室以往在八大公山采集保存的蛾类标本1000余号一起,共鉴定出19科175种,其中7种为湖南省新记录种。区系分析结果表明:该地区蛾类昆虫以东洋种为主。  相似文献   
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