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1 INTRODUCTIONGLOBALURBANISATIONUrbanisation is a worldwide phenomenon; the WorldResource Institute (2001) estimated that in 2025 morethan 50% of the African and Asian populations wouldbe living in urban areas. In Central and South Americathese figures will be between 75% and 85%. Urbanareas in developing countries will account fornearly 90% of the projected world populationincrease of 2.700 million people between 1995 and2030 (Figure 1) .Managing urban population change will b…  相似文献   

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The need to carry out biological conservation outside protected areas requires avoiding, minimizing or mitigating impacts brought about by habitat transformation upon the biota. Usually, forest plantations hold fewer species than the original forest. However, structurally complex plantations support more species and individuals than simpler ones. Here we test if this phenomenon occurs in amphibian and reptilian assemblages, analyzing information regarding their richness and abundance in forestry plantations from 14 countries and 72 case studies which compare species richness and abundance in plantations and forests. Among amphibians, species richness is lower in plantations than in forests while among reptiles there is no significant difference. The abundance of reptiles increases in plantations. Three studies dealt with reptile assemblages in relation to structural complexity of plantation, which suggest that species richness and abundance is higher in complex plantations. Despite accounting for 50 % of the terrestrial vertebrates, herpetological studies account for 15 % of the research available regarding the impact of plantation upon vertebrates, information deficiency that hampers decision-making on the conservation of herpetozoans outside protected areas.  相似文献   

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In order to approach the comprehensive results of CHFRP, Mayandong stock cooperation forest farm was selected as research object in Xupu county. These methods such as semi-structure interview, second data analysis and sample sites survey were used to investigate and study the ecological results, economical results and social results of CHFRP. The results show that CHFRP can restore the forest vegetation, promote forest growth, improve the physical and chemical properties and nutrition condition of forest soil, enhance economical result, and stabilize the production form in countryside. Therefore, the ecological results, economical results and social results of CHFRP are good. This research has found a way for reclaiming degraded forestland in Xupu county and other areas.  相似文献   

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Conjugation of δ-endotoxin from Bacillus thuringiensis with abamectin, a toxin of Streptomyces avermitilis, was carried out to form a new type of biocide, GCSC-BtA based on “Germany-China Scientific Cooperation” research, for the control of agricultural insect pests. The strategy for biochemical linkage was designed by conjugating an amino group in B.t. protoxin with a carboxyl group in carboxylated abamectin under the treatment of conjugator EDC [1-Ethyl-3-(3-dimethylaminopropyl carbodiimide Hydrochloride)]. The formation of B.t. protoxin was processed by solubilizing B.t. crystal in 25?mM dithiothreitol (DTT) at 37?°C for 2?h. The carboxylated abamectin was formed by carboxylating the NaH-activated abamectin with 10?mg/ml butyric anhydride at 111?°C in a water-circumfluent condensation device for 2?h. The conjugating reaction, consisting of 5?mg/ml B.t. protoxin, 10?mg/ml carboxylated abamectin and 19.17?mg/ml EDC, was successfully conducted at room temperature for 24?h. Significant differences were found between pure abamectin, carboxylated abamectin and the conjugated BtA by means of UV-photo absorptions recorded at wavelengths 354, 438, 518, 600?nm (P?<?0.01). LT50 of the conjugated GCSC-BtA to the 3rd instar larvae of Plutella xylostella (L.) (Lep., Plutellidae) was 35.27 μg a.i./ml, about 62?% and 76?% of that caused by the B.t. protoxin and the caxboxylated abamectin, respectively. The conjugated GCSC-BtA caused 87.14?% mortalities in larvae of P. xylostella, 93.75?% in adult Myzus persicae (Sulzer) (Hom., Aphididae) and 89.33?% in adult Phyllotreta vittata Fabricius (Col., Chrysomelidae) as compared to 48.33?% by the B.t. crystal only in P. xylostella. The symptoms caused by conjugated GCSC-BtA in the 3rd instar of P. xylostella were black color in the head part and white-yellow in the abdomen of dead larvae, which differed from the black color or the white-yellow all along the body caused by either the B.t. crystal or the abamectin, respectively. It was concluded that the conjugated GCSC-BtA biocide had a broader host spectrum and a faster killing speed than either the B.t. crystal or abamectin alone for the control of agricultural pests.  相似文献   

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Small-scale Forestry - Both the reducing emissions from deforestation and forest degradation program (REDD+) and community-based forest management (CBFM) aim to combat forest degradation and...  相似文献   

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The oxidized cellulose(OC) was prepared through selective oxidation of softwood dissolving pulp cellulose by HNO3/H3PO4/NaNO2 oxidant. The effects of oxidizing conditions, e.g., oxidizing time, temperature and dosages of NaNO2 on the yields and carboxyl groups contents of OC were studied. The structures and properties of OC samples were characterized by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD) and thermogravimetric analysis(TGA) respectively. The nanoparticle solution was prepared by dispersing the OC sample in aqueous solution under ultrasound wave. The sizes and morphologies of particles were characterized by dynamic light scattering(DLS) and transmission electron microscopy(TEM). The results showed that the nanoparticles were spherical in shape with monodisperse, and the sizes of micelles were in the range of 30 nm to 80 nm. The optimum conditions of OC preoaration were as the followings: reaction temperature 50 ℃, NaNO2 dosage 1.4 % and reaction for 12 h. Compared with water and cellulose, the OC nanoparticle was an excellent aqueous dispersant for multi-walled carbon nanotube(CNT). © 2018, Editorial Board of «Chemistry and Industry of Forest Products». All right reserved.  相似文献   

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云南大叶茶成熟种子子叶诱导产生愈伤组织,在改良MS并附加0.05mgl-12,4-D和0.5mgl-16-BA的琼脂培养基上经多次继代培养后,形成了五种类型的愈伤组织:黄色松散颗粒状(YF)、黄色半透明(YS)、绿色半透明(GS)、绿色坚硬(GH)、白色坚硬(WH).愈伤组织的分散程度及液体培养基的组成成分影响细胞悬浮培养物的建立:①黄色松散颗粒状愈伤组织最适合建立细胞悬浮系统;②在改良的MS液体培养基中添加较高的维生素(18.03mgl-1)和较高的生长素/细胞分裂素的比例(2,4-D/6-BA=0.1/0.5)及20mll-1的椰子乳,细胞生长和细胞分散程度良好.将YF接种到这种改良的MS的液体培养基中,在室温25±2℃,每天16小时散射光照射,120rpm的旋转振荡器上悬浮培养,三周后建立了云南大叶茶的胚性悬浮系统:系统中单细胞占5.36%,2~5个细胞的小细胞团占23.81%,6~20个细胞的细胞团占70.83%;有丝分裂指数为3.25%,活细胞率为70%~80%;悬浮培养物中细胞生长周期为10天左右.  相似文献   

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Conserving saproxylic beetles in temperate forests will require a better understanding of habitat requirements. So far, quantitative community studies have rarely considered their vertical requirements. In comparison with the tropical forest canopy, it remains to be seen whether a comparably high level of beetle diversity exists in the temperate forest canopy.We compared saproxylic beetle assemblages at two vertical levels in three temperate French forests. Two datasets originated from emergence traps of pine and oak deadwood substrates (mid-canopy and forest floor branches) in lowland forests. The third compared flying beetle fauna at mid-canopy and understory levels using pairs of flight interception traps in beech-fir mountain forests.Our study provided contrasting results regarding the contribution of each stratum to biodiversity. Whereas higher abundance and species richness were apparent in understory samples in beech-fir stands and in oak branches, no difference for richness - or even the opposite pattern for abundance - was observed in pine branches. A significant inter-strata dissimilarity was revealed in all datasets. Each stratum harbored specialist taxa. Exclusive canopy species accounted for 20-40% of all species. In accordance with dissimilarity partitioning, arboreal saproxylic beetle communities were not just nested subsets of ground assemblages.It is likely that microhabitat requirements, food availability and other non-resource-based factors (microclimate preference, species interactions) drive the stratification of beetle assemblages.Our results lend support (i) to the recommendation of a multi-strata sampling strategy for forest insects and (ii) to management practices in favour of valuable canopy micro-habitats.  相似文献   

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Key message

Growth and wood chemical properties are important pulpwood traits. Their narrow-sense heritability ranged from 0.03 to 0.49 in Eucalyptus urophylla × E. tereticornis hybrids, indicating low to moderate levels of genetic control. Genetic correlations were mostly favorable for simultaneous improvement on growth and wood traits. Additive and non-additive genetic effects should be considered in making a hybrid breeding strategy.

Context

Eucalypt hybrids are widely planted for pulpwood production purposes. Genetic variations and correlations for growth and wood chemical traits remain to be explored in Eucalyptus interspecific hybrids.

Aims

Our objectives were to clarify the heritability of growth and wood chemical traits and determine the genetic correlations between traits and between trials in E. urophylla × E. tereticornis hybrids.

Methods

Two trials of 59 E. urophylla × E. tereticornis hybrids derived from an incomplete factorial mating design were investigated at age 10 for growth (height and diameter) and wood chemical properties (basic density, cellulose content, hemi-cellulose content, lignin content, and syringyl-to-guaiacyl ratio). Mixed linear models were used to estimate genetic parameters.

Results

Narrow-sense heritability estimates were 0.13?0.22 in growth and 0.03?0.49 in wood traits, indicating low to moderate levels of additive genetic control. Genetic correlations were mostly positively significant for growth with basic density and cellulose content but negatively significant with hemi-cellulose and lignin contents, being favourablefavorable for pulpwood breeding purpose. Type-B correlations between sites were significant for all the traits except diameter and lignin content.

Conclusion

Hybrid superiority warrants the breeding efforts. An appropriate breeding strategy should be able to capture both additive and non-additive genetic effects.
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By investigation, the thesis analyses and summarizes the forming and developing of CHFRP In Xupu county. We select the Mayandong stock cooperation forest farm as object, adopt the methods such as semi-structure interview, analysing second data and surveying sample plots, analyse and study the process to clarify the property right, the profits allocated forms and the management forms. The results show that CHFRP can tentatively resolve the contradiction between the forestland using right scattered to every household and proper scale management demanded by forestry production. CHFRP can enhance economic result and stabilize the production form in countryside. The ecological result, economic result and social result of CHFRP are sufficient.  相似文献   

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Interspecific hybrids of Eucalyptus urophylla S. T. Blake × E. tereticornis Smith were used for quantitative genetic analysis of cold hardiness (CH) and growth traits height (H), diameter at breast height (D) and volume (V) at 0.5, 1.5, 2.5 and 4 years of age. The effect of E. tereticornis male variance was significant (P < 0.05) for CH as well as 2.5- and 4-year-old growth except for H 4, and E. urophylla female × E. tereticornis male interaction was significant for 0.5- and 1.5-year-old growth and CH except for CH 0.5, whereas E. urophylla female effect was not significant for the majority of traits analyzed. Both additive and dominance gene action were present in the genetics of all the traits measured at most ages, indicating that those traits may be improved by hybrid breeding. The σ D 2/σ A 2 ratios tended to decline after 1.5 years of age in CH and growth traits, implying that breeding value predictions derived from older performance might be more reliable. Estimates of narrow-sense heritability (h 2 ) for CH and growth ranged from 0.03 ± 0.05 to 0.28 ± 0.13, depending on trait and age. Additive genetic correlations between CH and V were 0.28 ± 0.48 and 0.69 ± 0.30 at ages 1.5 and 2.5, respectively, suggesting that selection for growth would cause a favorable increase in cold hardiness in E. urophylla × E. tereticornis hybrids.  相似文献   

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A significant share of the current seasonal losses of honey bee colonies can be attributed to the ectoparasitic mite Varroa destructor. Its direct feeding behaviour and virus vectoring decimate the colony until collapse if there is no effective control management in place. The synthetic pyrethroids such as tau-fluvalinate and flumethrin were intensively used to control the mite until multiple cases of resistance were reported since the early 1990s. Previous studies have shown that there are three different mutations at amino acid position 925 (L925V, I and M) of the V. destructor voltage-gated sodium channel associated with the resistance to these compounds. Here, we report the development of a new PCR–RFLP methodology to discriminate between susceptible and pyrethroid-resistant Varroa destructor mites. This is a DNA-based assay that proved to be as accurate and robust as the previously reported TaqMan®-based high-throughput genotyping assays but significantly cheaper and more accessible to low-resourced laboratories. It is also easier to identify resistant mites using the new assay. The beekeeping community will surely welcome this new technology since there are very few effective acaricides to deal with the mite. They are aware that pyrethroids can be very effective in absence of resistance so having the possibility to use them as alternative to other compounds as part of an integrated management strategy would be of great help for long-term controlling of the parasite.  相似文献   

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Introduction   

Future climatic scenarios demand an increasing involvement of management for forest preservation, but little is known on how forestry practices will benefit stands in facing variation of climatic components.  相似文献   

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Due to the expected increases of number and intensity of summer droughts in Central Europe the identification of drought tolerant ecotypes becomes more important in future forestry. A common garden experiment with seedlings of Fagus sylvatica provenances from the center (Germany) and eastern margin (Poland) of the species’ distribution range was conducted. Responses of morphological, physiological, chemical and growth parameters to three drought treatments were analyzed. Relative growth rates of the marginal provenance were lower as compared to the central provenance. The marginal seedlings showed a tendency to higher total biomasses because of higher seed masses. In both provenances drought decreased biomass production and root/shoot ratio which was lower in the central provenance. A lower specific root area of the marginal provenance indicated a better adaptation to low xylem water potentials. Under moderate drought, lower leaf δ13C signatures may indicate lower stomatal limitation (or a reduced rate of CO2 assimilation) in the marginal provenance. We conclude that marginal beech provenances may exhibit a better drought adaptation.  相似文献   

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Key message

Soil texture and temperature-related variables were the variables that most contributed to Nothofagus antarctica forest height in southern Patagonia. This information may be useful for improving forest management, for instance related to the establishment of silvopastoral systems or selection of suitable sites for forest reforestation in southern Patagonia.

Context

Changes in forest productivity result from a combination of climate, topography, and soil properties.

Aims

The relative importance of edaphic and climatic variables as drivers of productivity in Nothofagus antarctica forests of southern Patagonia, Argentina, was evaluated.

Methods

A total of 48 mature stands of N. antarctica were selected. For each study site, we measured the height of three mature dominant trees, as an indicator of productivity. Seven soil, five spatial, and 19 climatic features were determined and related to forest productivity. Through partial least squares regression analyses, we obtained a model that was an effective predictor of height of mature dominant trees in the regional data set presented here.

Results

The four variables that most contributed to the predictive power of the model were altitude, temperature annual range, soil texture, and temperature seasonality.

Conclusion

The information gathered in this study suggested that the incidence of the soil and temperature-related variables on the height of dominant trees, at the regionally evaluated scale, was higher than the effect of water-related variables.
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Over the last few decades, important advances have been made in understanding of host–parasitoid relations and their applications to biological pest control. Not only has the number of agent species increased, but new manipulation techniques for natural enemies have also been empirically introduced, particularly in greenhouse crops. This makes biocontrol more complex, requiring a new mathematical modeling approach appropriate for the optimization of the release of agents. The present paper aimed at filling this gap by the development of a temperature- and stage-dependent dynamic mathematical model of the host–parasitoid system with an improved functional response. The model is appropriate not only for simulation analysis of the efficiency of biocontrol agents, but also for the application of optimal control methodology for the optimal timing of agent releases, and for the consideration of economic implications. Based on both laboratory and greenhouse trials, the model was validated and fitted to the data of Chelonus oculator (F.) (Hym.: Braconidae) as a biological control agent against the beet armyworm, Spodoptera exigua Hübner (Lep.: Noctuidae). We emphasize that this model can be easily adapted to other interacting species involved in biological or integrated pest control with either parasitoid or predator agents.  相似文献   

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