Algal flora and its importance in the economy of rice fields

Summary The growth of algae has been studied simultaneously in nature and in soil culture of some of the paddy fields. Although some of them are common to both, there are conspicuous differences in the algal vegetation under the two conditions. The algal growth is mainly governed by the seasonal and other ecological conditions of their habitat.The growth of algae effects the paddy crop in various ways i.e. by nitrogen fixation and secretion of growth promoting substances etc.Read at the annual meeting of the Sci. and Techn. Society, Kanpur, Dec. 1963.     

转基因抗虫杂交稻对非靶标害虫稻飞虱田间种群动态的影响

以常规稻Ⅱ优明86为对照,研究了转双价基因(cry1Ac SCK)抗虫杂交稻Ⅱ优科丰6号对稻飞虱田间种群的影响。采用吸虫器法调查结果表明,Ⅱ优科丰6号在水稻的整个生育期内,对白背飞虱Sogatella fucifera、褐飞虱Nilaparvata lugens种群及飞虱若虫群体均未产生显著影响;田间卵量剥查镜检结果表明,Ⅱ优科丰6号生长前期对白背飞虱的产卵有一定的吸引和刺激作用,而后期对褐飞虱的产卵有一定的拒避和抑制作用,但从整个生育期来看对飞虱的产卵行为无显著影响。因此,从短期研究结果分析,Ⅱ优科丰6号对非靶标害虫稻飞虱田间种群表现安全,同时也未引起稻飞虱田间种群猖獗。     

Unraveling the drivers of intensifying forest disturbance regimes in Europe

Natural disturbances like wildfire, windthrow and insect outbreaks are critical drivers of composition, structure and functioning of forest ecosystems. They are strongly climate‐sensitive, and are thus likely to be distinctly affected by climatic changes. Observations across Europe show that in recent decades, forest disturbance regimes have intensified markedly, resulting in a strong increase in damage from wind, bark beetles and wildfires. Climate change is frequently hypothesized as the main driving force behind this intensification, but changes in forest structure and composition associated with management activities such as promoting conifers and increasing standing timber volume (i.e. ‘forest change’) also strongly influence susceptibility to disturbances. Here, we show that from 1958 to 2001, forest change contributed in the same order of magnitude as climate change to the increase in disturbance damage in Europe's forests. Climate change was the main driver of the increase in area burnt, while changes in forest extent, structure and composition particularly affected the variation in wind and bark beetle damage. For all three disturbance agents, damage was most severe when conducive weather conditions and increased forest susceptibility coincided. We conclude that a continuing trend towards more disturbance‐prone conditions is likely for large parts of Europe's forests, and can have strong detrimental effects on forest carbon storage and other ecosystem services. Understanding the interacting drivers of natural disturbance regimes is thus a prerequisite for climate change mitigation and adaptation in forest ecosystem management.     

Effects of the surrounding landscape on waterbird populations in estuarine ecosystems of central Chile

Wetlands Ecology and Management - Waterbirds have high potential as bioindicators of the status and functioning of estuarine ecosystems, because they respond to multiple stress factors in a wide...     

Identifying new buffer areas for conserving waterbirds in the Mediterranean basin: the importance of the rice fields in Extremadura,Spain

The impact of wetland loss on migratory waterbirds can be mitigated by the presence of anthropogenic habitats such as rice fields. In the Mediterranean basin, wetlands have been drained and altered to such a degree that their very existence is threatened. It is, therefore, essential to identify key buffer areas in the basin to develop conservation strategies for migratory waterbirds. In Extremadura, continental SW Spain, 30,000 ha of new rice fields have created since the 1960s. The present study describes for the first time the waterbird community associated with these inland rice fields, and addresses the question of the potential value of this area in buffering the loss of natural wetlands for populations of waterbirds using the East Atlantic Flyway (EAF). The waterbird community studied consisted of 45 species, with population levels reaching values of international importance (>1% of the biogeographical population using EAF) for the Common Crane Grus grus (19%), Black-tailed Godwit Limosa limosa (1.2%), Black-winged Stilt Himantopus himantopus (1.2%), and Cattle Egret Bubulcus ibis (1%). The presence of these rice fields may be modifying the wintering and/or feeding sites of some waterbird species such as the Common Crane and Black-tailed Godwit. Unfortunately, there is no legal protection for this area. We propose the designation of these rice fields as a Special Protection Area for birds.     

Latitudinal trends in breeding waterbird species richness in Europe and their environmental correlates

We analysed the latitudinal trend in the number of breeding waterbird species in Europe using the main river basins as geographic units. The number of breeding waterbird species decreases southward, but this latitudinal trend is composed of two opposed patterns: a southward increase in the number of resident species (RS) and a southward decline in the number of aestival species (SS). Following both a bivariate and a multivariate approach, we tested nine hypotheses about the environmental causes of these trends. Using Partial Regression Analysis and Path Analysis, we found that SS richness depends on the bloom in food availability in areas with high seasonality more than on the other environmental factors; environmental stress due to an excess of energy is the second most important factor involved, whereas the third factor involved in the distribution of SS richness is competition with RS. For RS the factors involved are the climatic stability of the basins and their productivity. We also discuss the suitability of river basins as observational units in this kind of analyses and the marginal influence of their surface area in the latitudinal gradients detected here.     

Effects of organic and inorganic fertilisers on mosquito populations in rice fields of southern India

The effects of nitrogenous (inorganic) fertilisers, organic manures and blue-green algae (BGA) biofertiliser on mosquito populations (Diptera: Culicidae) were studied in rice fields of Madurai, Tamil Nadu, south India, with particular attention to Culex vishnui Theobald, Cx. pseudovishnui Colless and Cx. tritaeniorhynchus Giles, the vectors of Japanese encephalitis (JE). The application of urea, a nitrogenous fertiliser, in rice fields significantly increased the grain yield and the population densities of mosquito larvae and pupae (anophelines as well as culicines) in a dose-related manner. Fields treated with inorganic fertilisers (N, P, K) had significantly higher population densities of mosquito immatures than fields treated with organic manures (farmyard manure and green manure). Without nitrogenous fertiliser, BGA increased paddy yield without enhancing mosquito production. Therefore, the use of BGA with less nitrogenous fertiliser is recommended, which is beneficial economically and agronomically to the farming community and also significantly reduces mosquito production in rice fields. Increased use of nitrogenous fertiliser over the past two decades may have contributed to the increased severity of Japanese encephalitis epidemics, vectors of which breed in rice fields.     

Half a century of changes in waterbird populations in a semiarid wetland system

Mexican inland wetlands in the arid and semiarid interior highlands historically held very large numbers of waterbirds. However, they have been deteriorated by agriculture, industrial and urban development, tourism and aquaculture, although the effects of this are known poorly. At the southern end of the Central Plateau of Mexico, the region of El Llano, in the states of Aguascalientes and Jalisco, is densely dotted with wetlands amidst an agricultural landscape. The wetlands that existed at the time of Spanish contact have disappeared or been modified, but many new ones have been created, including large and mid-size reservoirs, as well as small cattle watering tanks. The importance of this region for waterbirds was analyzed based on the data from the USFWS mid-winter Mexican waterfowl surveys, and surveys by ourselves in 1984–1985 and from 2010 to 2014. The data exhibited a peak in diving ducks in the late 1970s, which might reflect reservoir restoration and, or creation. Wetland water levels as well as their use by waterbirds was highly variable during the study period, and some sites that were important in 1984–1985 have silted and dried up. The major waterbird trend in the survey area has been a steady increase in the number of the threatened Mexican Duck since the late 1970s until 2010–2011, that might have been resulted from a reduction in its hunting and egg collecting, and, or improvement in nesting habitat, along with reservoir creation or restoration.     

转 Bt 基因水稻对三化螟自然种群的影响

为了了解水稻重要害虫三化螟 Scirpophaga incertulas（Walker）对转 Bt 基因水稻产生抗性的潜在风险,本文利用自然种群生命表,研究了第 3 代三化螟在转Bt基因杂交稻汕优 63 及非转 Bt 基因杂交稻汕优 63 上的种群参数。结果表明：在 Bt 稻上1～2 龄幼虫的存活率为 4.03%,极显著低于非转基因 SY63（55.76%）;Bt 稻上幼虫为害率为1.75%,极显著低 于非转基因 SY63（5.98%）;Bt 稻上存活的幼虫发育历期明显长于非转 Bt SY63。     

Unraveling the complex maternal history of Southern African Khoisan populations

The Khoisan populations of southern Africa are known to harbor some of the deepest‐rooting lineages of human mtDNA; however, their relationships are as yet poorly understood. Here, we report the results of analyses of complete mtDNA genome sequences from nearly 700 individuals representing 26 populations of southern Africa who speak diverse Khoisan and Bantu languages. Our data reveal a multilayered history of the indigenous populations of southern Africa, who are likely to be the result of admixture of different genetic substrates, such as resident forager populations and pre‐Bantu pastoralists from East Africa. We find high levels of genetic differentiation of the Khoisan populations, which can be explained by the effect of drift together with a partial uxorilocal/multilocal residence pattern. Furthermore, there is evidence of extensive contact, not only between geographically proximate groups, but also across wider areas. The results of this contact, which may have played a role in the diffusion of common cultural and linguistic features, are especially evident in the Khoisan populations of the central Kalahari. Am J Phys Anthropol 153:435–448, 2014. © 2013 Wiley Periodicals, Inc.     

Identification of quantitative trait loci across recombinant inbred lines and testcross populations for traits of agronomic importance in rice

This study was conducted to determine whether quantitative trait loci (QTL) controlling traits of agronomic importance detected in recombinant inbred lines (RILs) are also expressed in testcross (TC) hybrids of rice. A genetic map was constructed using an RIL population derived from a cross between B5 and Minghui 63, a parent of the most widely grown hybrid rice cultivar in China. Four TC hybrid populations were produced by crossing the RILs with three maintaining lines for the widely used cytoplasmic male-sterile (CMS) lines and the genic male-sterile line Peiai64s. The mean values of the RILs for the seven traits investigated were significantly correlated to those of the F1 hybrids in the four TC populations. Twenty-seven main-effect QTL were identified in the RILs. Of these, the QTL that had the strongest effect on each of the seven traits in the RILs was detected in two or more of the TC populations, and six other QTL were detected in one TC population. Epistatic analysis revealed that the effect of epistatic QTL was relatively weak and cross combination specific. Searching publicly available QTL data in rice revealed the positional convergence of the QTL with the strongest effect in a wide range of populations and under different environments. Since the main-effect QTL is expressed across different testers, and in different genetic backgrounds and environments, it is a valuable target for gene manipulation and for further application in rice breeding. When a restorer line that expresses main-effect QTL is bred, it could be used in a number of cross combinations.     

Unraveling cell populations in tumors by single-cell mass cytometry

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The impact of changing irrigation practices in rice fields on frog populations of the Kanto Plain, central Japan

Rice fields are important substitute wetlands for frogs. Traditionally, rice fields in Japan were supplied with water and drained via shallow earth ditches (old-style). In the last 30 years, however, more than 80% of rice fields have been converted to a new irrigation system in which water is typically supplied through underground pipes via taps and is drained into deep, concrete-sided ditches (new-style). We compared the occurrence of frogs in paired areas of old- and new-style rice fields at six locations in Ibaraki Pref., central Japan, from May to August 1995. The Japanese tree frog (Hyla japonica) did not differ in abundance between the two types of rice fields, but the Japanese brown frog (Rana japonica) and the Tokyo daruma pond frog (Rana porosa porosa) preferred the old-style rice fields. These findings suggest that the status ofRana species has been adversely affected by the conversion of rice fields to the new irrigation system. Modification of the deep, U-shaped concrete ditches and the water management regime during the spawning season is needed to safeguard these species.     

Chironomids of Italian rice fields

Studies on chironomids of Italian rice fields began in 1914, but a comprehensive faunistic picture of Italian rice field chironomids was provided only by COCCHI in 1966. In 1988 and 1989 field research south of Verona (northern Italy) permitted us to confirm the results of COCCHI regardingC. sylvestris andChironomus spp., and to increase the number of known species of Italian rice field chironomids. The list of species which are injurious to rice is similar to that of other European countries, with the exception ofHarnischia falcata andTanytarsus sp. The type and period of damage is different for certain species (e.g. Cricotopus sylvestris) in Italy in comparison to other countries. A few agrotechnical steps are recommended to control pest species. The finding of the parthenogenetic speciesParatanytarsus grimmii in lab. aquaria used for rearing purposes is documented.     

Optimising hydrological conditions to sustain wintering waterbird populations in Poyang Lake National Natural Reserve: implications for dam operations

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Silent fields: the decline of farmland birds in Europe

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