Impact of landscape management on the genetic structure of red squirrel populations

Landscape management practices that alter the degree of habitat fragmentation can significantly affect the genetic structure of animal populations. British red squirrels use "stepping stone" patches of habitat to move considerable distances through a fragmented habitat. Over the past few decades, the planting of a large conifer forest has connected groups of forest fragments in the north of England with those in southern Scotland. This "defragmentation" of the landscape has resulted in substantial genetic mixing of Scottish and Cumbrian genes in squirrel populations up to 100 kilometers from the site of the new forest. These results have implications for the conservation management of animal and plant species in fragmented landscapes such as those found in Britain.     

Simulated increase of hurricane intensities in a CO2-warmed climate

Hurricanes can inflict catastrophic property damage and loss of human life. Thus, it is important to determine how the character of these powerful storms could change in response to greenhouse gas-induced global warming. The impact of climate warming on hurricane intensities was investigated with a regional, high-resolution, hurricane prediction model. In a case study, 51 western Pacific storm cases under present-day climate conditions were compared with 51 storm cases under high-CO2 conditions. More idealized experiments were also performed. The large-scale initial conditions were derived from a global climate model. For a sea surface temperature warming of about 2.2 degrees C, the simulations yielded hurricanes that were more intense by 3 to 7 meters per second (5 to 12 percent) for wind speed and 7 to 20 millibars for central surface pressure.     

High-frequency skywave radar measurements of hurricane anita

We tracked and monitored hurricane Anita over a 5-day period by using the SRI-operated Wide Aperture Research Facility (WARF) high-frequency skywave radar. The WARF-derived positions for Anita agreed to within +/- 19 kilometers of the coincident temporal positions along the National Hurricane Center's smooth track. Hurricane Anita passed near the open ocean-moored buoy EB-71 of the National Oceanic and Atmospheric Administration, and measurements of wind direction, wind speed, and significant wave height made during this period at the WARF and in situ at the buoy showed agreement of 7 degrees , 0.4 meter per second, and 0.5 meter, respectively. The WARF estimates of longshore coastal surface currents showed good agreement with measurements made at a moored current meter.     

水稻条纹叶枯病成灾原因初探

针对水稻条纹叶枯病在江淮地区大发生及其治理中存在的问题,分析了该病的为害特点和影响因素,提出了一些措施与建议。     

Virginia barrier island configuration: a reappraisal

The 12 Virginia barrier islands are divided into three groups on the basis of historical retreat rates and characteristics. The growth and reversal of inlet offsets is a long-term event that results from the operation of known coastal processes. Both geomorphic evidence and wave refraction analyses indicate that shoreline irregularity will diminish with time. There is no basis for the prediction (or expectation) that cape-like features will evolve along this shoreline.     

Deposit from a giant wave on the island of lanai, hawaii

Limestone-bearing gravel, the newly named Hulopoe Gravel, blankets the coastal slopes on Lanai. The deposit, which reaches a maximum altitude of 326 meters, formerly was believed to have been deposited along several different ancient marine strandlines, but dated submerged coral reefs and tide-gauge measurements indicate that the southeastern Hawaiian Islands sink so fast that former worldwide high stands of the sea now lie beneath local sea level. Evidence indicates that the Hulopoe Gravel and similar deposits on nearby islands were deposited during the Pleistocene by a giant wave generated by a submarine landslide on a sea scarp south of Lanai.     

松材线虫入侵对马尾松林主要种群生态位的影响

采用定量分析方法,对松材线虫不同受害阶段的马尾松群落中13个主要种群进行了生态位研究.以群落组成类型: ①马尾松＋NFDA4木＋白栎,②黑松＋马尾松＋冬青＋柃木,③马尾松＋冬青＋栀子+短柄NFDA5,④马尾松＋篌竹+NFDA4木,⑤木荷＋马尾松＋苦槠＋短柄NFDA5,⑥栓皮栎＋冬青＋杜虹花,及所建立的综合资源梯度指数（10～70）综合为一维资源位,调查6个资源位,定量测定不同受害阶段马尾松群落主要种群生态位宽度、生态位相似比例、生态位重叠,并阐述了各种群生态位的生态学意义.结果表明:由于松材线虫的入侵,加之随后的人为伐除马尾松受害木,马尾松林正朝着阔叶林和针阔混交林两个方向演替.      

Supersaturated island faunas: a species-age relationship for lizards on post-pleistocene land-bridge islands

Lizard faunas on post-Pleistocene land-bridge islands in the region of Baja California were examined for the effect of island age on species diversity. Species diversity and age are significantly correlated; and when the variation in species diversity attributable to area and latitude are removed, the corrected species diversity plotted against island age produces a relaxation or extinction curve. These results provide evidence for supersaturated faunas which are relaxing to lower levels of species diversity consistent with the equilibrium theory of island biogeography.     

Deconvolution of the factors contributing to the increase in global hurricane intensity

To better understand the change in global hurricane intensity since 1970, we examined the joint distribution of hurricane intensity with variables identified in the literature as contributing to the intensification of hurricanes. We used a methodology based on information theory, isolating the trend from the shorter-term natural modes of variability. The results show that the trend of increasing numbers of category 4 and 5 hurricanes for the period 1970-2004 is directly linked to the trend in sea-surface temperature; other aspects of the tropical environment, although they influence shorter-term variations in hurricane intensity, do not contribute substantially to the observed global trend.     

Modulation of hurricane activity in the gulf of mexico by the madden-julian oscillation

The Madden-Julian oscillation (MJO) is a large-scale episodic modulation of tropical winds and precipitation that travels eastward from Asia to America, with a characteristic repeat time of 30 to 60 days. Here it is shown that when MJO wind anomalies in the lower troposphere of the eastern Pacific are westerly, Gulf of Mexico and western Caribbean hurricane genesis is four times more likely than when the MJO winds are easterly. Accurate predictions of the MJO may lead to improved long-range forecasts of tropical cyclone activity.     

Cavernicoles in lava tubes on the island of hawaii

Cave-adapted arthropods have evolved in lava tubes in Hawaii. This is the first report of cavernicoles from the Hawaiian islands. The specialization of the cavernicolous insects and the recent origin of the lava tubes suggest that subterranean connections between lava tubes regularly occur and provide dispersal routes. The discovery that lava tubes were colonized by representatives of the adaptively radiating native fauna offers significant potential for evolutionary studies.     

Effect of lizards on spider populations: manipulative reconstruction of a natural experiment

Which species affect one another, how intensely, and the mechanisms of those effects are crucial data for understanding how ecological communities work. Tropical islands without lizards, the major top predators, have about ten times as dense web spider populations as those with lizards; processes responsible for this effect were experimentally simulated by removing lizards from randomly selected mainland plots. Spider densities in removal plots averaged 2.5 times as high as controls. Spider survival, prey abundance, and prey consumption were all negatively affected by lizards. Contrary to most studies, predator removal caused an increase in the number of spider species.     

海岛棉的一个富含亮氨酸重复受体蛋白基因的克隆和功能分析

通过染色体步移获得了海岛棉的一个受体蛋白基因Gb Vdr1,其开放阅读框为3 387个核苷酸,编码1 128个氨基酸,编码蛋白分子量为1.249×105,等电点为5.86。Gb Vdr1与陆地棉抗病材料常抗棉和感病材料渝棉1号中的同源基因Gh Vdr1和Gh Vdr1-1的相似度高达99.85%。Gbvdr1具有信号肽、跨膜区、LRR重复区、蛋白质降解相关的PEST结构域以及内吞信号。Gb Vdr1在根茎中的表达量高于叶片,其对非落叶型黄萎病菌株BP2的反应较落叶型菌株V991的更为强烈,并且这种差异在茎和根中更为明显。Gb Vdr1定位于细胞膜上。PCR鉴定共获得Gb Vdr1过表达转基因株系23株,对目的基因表达量最高的株系进行黄萎病抗性鉴定,结果表明转基因株系对BP2的抗性显著增强,但是对V991没有抗性。转基因株系接种黄萎病后防卫反应(PR)相关基因PR1、PR5、EDS1以及GST1的表达量较野生型显著增加。对于Gb Vdr1的功能分析结果表明其参与了棉花对BP2的抗性反应。