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Volume ,2017 Issue 6
Volume ,2017 Issue 6
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2008,28(12):6272-6281, DOI: 10.1016/S1872-2032(09)60016-0
Abstract:
Hirudinea in China were reviewed. The ecological distribution of Hirudinea, the population dynamics of H. hainana, the adaptation of H. hainana to temperature, soil humidity and pH, the response of H. hainana to temperature, relative humidity and light, and the effects of human activities on H. hainana populations were discussed. The land-leeches' behavior ecology, including (1) the locomotion of H. hainana such as shortening, oscillating, rotating, sucking cleaning, rubbing and foraging behaviors; (2) the factors influencing these behaviors; (3) the ecological significance, was also discussed. The ecology of freshwater leeches including (1) behavior in paddy fields of Ninghsien, Zhejiang Province, China; (2) relationship between population dynamics of Whitmania laevis and chemical factors in paddy fields of Guangzhou, China; (3) chemical environment of blood-sucking Hirudinaria manillensis in paddy fields of Guangzhou was described. The study also discussed the foraging, growth dynamics, life recycle and biology of reproduction of blood-sucking land-leech H. hainana and freshwater leech Hirudinaria manillensis, the taxonomy and the zoogeography. In addition, the morphology including histology and anatomy of the organic system of H. hainana was described. The Hirudinea can be classified into 2 subclasses (Branchiobdellidea and Euhirudinea), 3 orders (Branchiobdellida, Rhynchobdellida and Arhynchobdellida), 9 families, 33 genera and 111 species. The response of leeches to pesticides, including toxicity (LD50, LD95) of different pesticides to H. hainana, was presented. Medical usage of the leech Hirudin from salivary glands as anticoagulant material was discussed. Hirudin (from Hirudo medicinalis), Haemadin (from land-leech), and hementi (from Hementeria ghilianii) were identified and isolated.
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Ma Jinhu, Xing Guofang, Yang Wenxiu, Ma Leilei, Gao Mei, Wang Yuguo, Han Yuanhuai
2012,32(1):50-56, DOI: 10.1016/j.chnaes.2011.12.004
Abstract:
Amaranthus retroflexus L. and Chenopodium glaucum L. are two widely distributed destructive weeds. Their strong adaptability and massive seed production make them the hardest weeds to deal with. This present study intended to investigate the effect of leachate from Eupatorium adenophorum on the growth of these weeds and explore the potential to develop an environmental friendly strategy to use the leachate to control the weeds.
Seeds of A. retroflexus L. and C. glaucum L. were soaked in solutions containing 0%, 0.6%, 1.25%, 2.5%, and 5% leachate from E. adenophorum leaves. A. retroflexus and C. glaucum seedlings grown in pots were sprayed with leachate solutions in the same concentration range. The effects of these leachate solutions on membrane permeability and germination of seeds, and growth and physiological characteristics of the seedlings were investigated. The highest concentration of leachate (5%) caused significant damage to the cell membrane of seeds of both weed species, whereas lower concentrations (0.6%) promoted repair of the membrane system, as reflected by higher and lower than control in relative conductivity (RC), respectively. Different concentrations of leachate showed distinct allelopathic inhibitory effects on the two weed species; lower concentrations showed weak inhibitory or even positive effects, whereas higher concentrations showed stronger inhibitory effects. Higher concentrations of leachate (2.5% and 5%) delayed germination and significantly decreased the emergence rate of the seeds, survival rate, and dry matter accumulation of the seedlings. When treated by 5% leachate, the emergence date of A. retroflexus was delayed by 3.6 d, emergence rate of the seeds and survival rate was 69.1% and 70.6% of the control, respectively, seedling dry matter was 48.6% less than the control; In the case of C. glaucum, the emergence date was delayed by 2.7 d, emergence rate of the seeds and survival rate was 45.1% and 58.6% of the control, respectively, seedling dry matter was 44.7% less than the control. There were significant interactions among the different concentrations of leachate and the length of treatment period with respect to activities of antioxidant enzymes, malondialdehyde (MDA) contents, and chlorophyll contents. Seedlings treated with 0.6%, 1.25%, or 2.5% leachate solution for 24–72 h showed increased superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities. When seedlings were treated with leachate solutions for 96 h, antioxidant enzyme activities and chlorophyll content decreased in A. retroflexus, but only CAT activity decreased in C. glaucum. When seedlings of the two weed species were treated with 5% leachate solution, CAT activity and chlorophyll content decreased and MDA content gradually increased with longer treatment times (from 24 to 96 h). The two weed species showed different allelopathic responses to E. adenophorum; A. retroflexus was more sensitive than C. glaucum.
Based on the investigation, it could be speculated that the delayed germination and low germination rate of the weeds after treatment by leachate could be due to the fact that leachate damaged the membrane system of the seeds. By delaying germination, lowering the germination rate of the weeds and inhibiting seedling growth, leachate from E. adenophorum could provide an effective way of controlling the weeds. -
2012,32(4):209-214, DOI: 10.1016/j.chnaes.2012.05.003
Abstract:
The evaluation of microbial molecular diversity has been mainly based on the extraction of total DNA from environmental samples. The indirect extraction methods, which have been used for prokaryotes, have never been used to recover soil microeukaryotic DNA. We evaluated the efficiency of an improved indirect DNA extraction protocol developed herein and the direct lysis (the sodium dodecyl sulfate (SDS)-based method and commercial DNA extraction kit) on estimating the molecular diversity of soil microbial eukaryotes. DNA quality and quantity as well as denaturing gradient gel electrophoresis (DGGE) profiles were determined using three soil samples from different stations. The indirect method detected the highest DGGE bands in spite of the low DNA yield. The commercial kit detected a lower number of DGGE bands than the indirect method. The SDS-based method produced the lowest DGGE bands and DNA purity but the highest yield. Using the indirect method, we further evaluated the effect of freezing and air-dried preservations on estimating the microeukaryotic diversity. In spite of the low DNA yield obtained from the air-dried preservation, no significant differences were found in either the number of DGGE bands or the DNA purity between two manners. Our results indicate that the improved indirect method could obtain a high purity of intracellular DNA and high efficiency in the estimation of molecular diversity of soil microbial eukaryotes.
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Wang Xuezhi, Xu Weihua, Ouyang Zhiyun, Liu Jianguo, Xiao Yi, Chen Youping, Zhao Lianjun, Huang Junzhong
2008,28(2):821-828, DOI: 10.1016/S1872-2032(08)60030-X
Abstract:
Ecological-niche factor analysis (ENFA) is a multivariate approach to study geographic distribution of species on a large scale with only “presence” data. It has been widely applied in many fields including wildlife management, habitat assessment and habitat prediction. In this paper, this approach was applied in habitat suitability assessment for giant pandas in Pingwu County, Sichuan Province, China. With “presence” data of giant pandas and remote sensing data, habitat suitability of pandas in this county was evaluated based on ENFA model, and spatial distribution pattern of nature reserves and conservation gaps were then evaluated. The results show that giant pandas in this county prefer high-elevation zones (> 2128 m) dominated by coniferous forest, and mixed coniferous and deciduous broadleaf forest, and avoid deciduous broadleaf forest and shrubs. Pandas avoid staying at habitats with human disturbances. Farmland is a major factor threatening panda habitat. Panda habitat is mainly distributed in north and west of Pingwu with a total area of 234033 hm2, 106345 hm2 for suitable habitat and 127688 hm2 for marginally suitable habitat). 3 nature reserves were located in Pingwu, covering over 49.2% of total suitable habitat and 45.6% of total marginally suitable habitat. Although 47.2% of panda habitat was in reserves under protection, connectivity between reserves was weak and a conservation gap existed in the north part of Pingwu. Thus, a new nature reserve in Baima and Mupi should be established to link the isolated habitats.
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Zhu Wenfeng, Wang Songliang, Claude D. Caldwell
2012,32(1):9-17, DOI: 10.1016/j.chnaes.2011.11.001
Abstract:
Intrusive agriculture development, searching for higher profitability, has inflicted permanent damage to agroecosystems. Rapid deterioration of structure and functional properties in agroecosystems has intensified the need for research on agroecosystem health and agroecosystem management. This paper describes the concept of agroecosystem health which plays an important conceptual role in evaluating agroecosystem and agricultural research. Firstly, the development of agroecosystem health research is reviewed, and agroecosystem health from various dimensions is provided. Then, the methods and general criterias of agroecosystem health assessment are outlined, and a model for evaluating agroecosystem health is established. Finally, pathways of agroecosystem management from a holistic dimension are proposed to promote agroecosystem health and provide a scientific basis for making science-based policy decisions and formulating new plans in agricultural development.
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Zheng Mingguo, Cai Qiangguo, Chen Hao
2007,27(9):3572-3581, DOI: 10.1016/S1872-2032(07)60075-4
Abstract:
Whether vegetation reduces soil loss by reducing runoff volume or rather by changing runoff-sediment yield relationship has received little attention. Base on the observed data from monitoring stations and the published data from other research, this issue is addressed at different scales in hilly areas of the Loess Plateau, North China. At the plot scale, vegetation helps reduce soil loss not only by reducing runoff volume, but also by changing the runoff-sediment yield relationship, resulting that the sediment-reduction rate is higher than the runoff-reduction rate. At the watershed scale, gully erosion and mass wasting process are dominant. Vegetation measures are insufficient to control local mass movement, implying that sediment availability remains high even after vegetation is established. It is also hard for slope vegetation to change the capacity of the sediment transport system at the watershed scale. Therefore, vegetation cannot change the runoff-sediment yield relationship at the watershed scale. This implies that vegetation reduces sediment yield only by reducing runoff volume and the sediment-reduction rate approximates the runoff-reduction rate at the watershed scale. Other slope measures for soil conservation such as terraces are considered to have the same effect on the runoff-sediment yield relationship as the vegetation. Several case studies involving different spatial scales are presented and confirm this conclusion.
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Xiang Changguo, Zhang Pingjiu, Pan Genxing, Qiu Duosheng, Chu Qiuhua
2006,26(6):1667-1673, DOI: 10.1016/S1872-2032(06)60030-9
Abstract:
Influence of the agricultural management practices on soil quality and the ecosystem functioning has been an increasing concern in soil science and ecology with sustainable agriculture. This study deals with the changes of soil earthworm communityfrom a paddy soil under different long-term fertilizations. The soil earthworms were collected and counted from different fertilizer treated plots in the field after the rape harvest in May 2004, and their taxonomic groups were determined under a binocular stereoscope at the laboratory. The body of the earthworm (Metaphire californica) was crushed by a cell crusher to collect protein, and the protein molecules with different sizes were analyzed by electrophoresis. Furthermore, the Metaphire californica collected was hydrolyzed and the aliquots were subject to an amino acid auto-analyzer. The results showed that totally seven species of earthworms were recognized in the paddy field with the number varying with different fertilization treatments. The structure of earthworm communities was dramatically affected by the fertilization practice. Under chemical fertilization only, both the number of earthworm species and the quantity of individuals were significantly smaller than those under other treatments, or even than those under no fertilization. Furthermore, there was an obvious decrease in the total amino acid and the contents of most individual amino acids of Metaphire californica under chemical fertilization only, compared with those under the combined fertilization of chemical and organic fertilizers. Although chemical fertilizers in combination with rice straw return increased earthworm amino acid content, long-term pig manure application tended to increase earthworm protein content. As a molecular footprint, long-term chemical fertilization caused a reduction in the content of protein with MW less than 25 kd, but a significant increase in that of protein with molecule size around 33 kd. Our study demonstrated that different fertilizations affected not only earthworm population but also diversity and richness in the paddy soil after 16 years of treatment, and that long-term chemical fertilization may impact the soil animal community and, thus, influence the paddy ecosystem functioning for yield stability. This study implicated that not only the community structure but also the amino acid metabolism for life functioning of earthworms in cropland soils may pose significant responses to the agricultural management practices.
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Song Fuqiang, Song Ge, Dong Airong, Kong Xiangshi
2011,31(6):322-327, DOI: 10.1016/j.chnaes.2011.09.001
Abstract:
Arbuscular mycorrhizal (AM) fungi colonize the roots of over 80% of terrestrial plant species, forming mutually beneficial symbioses. During the colonization process, symbiotic partners recognize each other, and undergo observable morphological and physiological changes; indicating that symbiosis formation involves multiple factors that are finely regulated. Sometimes host plants generate a transient, weak, defense response. This response and its down-regulation play a very important role in the development of AM symbioses. Although AM fungi can infect a wide range of host root tissues, which host defense may play a crucial role is hypothesized from the fact that hyphal expansion is only observed in the root cortex.
We discuss five defense mechanisms. (1) The degradation of exogenous elicitors. The host’s weak defense response may be due to the degradation of the exogenous elicitor chitin, or the prevention of release of an endogenous inductor from the plant cell wall. (2) The inactivation of defense signal molecules. Some defense signal molecules such as hydrogen peroxidase, salicylic acid (SA), and jasmonic acid (JA), are inactivated in host plants. This helps to avoid the turn-on of defense-related genes and facilitate mycorrhizal formation. (3) The regulation of plant hormones and plant photosynthates. Plant hormone levels and plant photosynthate metabolism both change during AM colonization. These mechanisms need further exploration. (4) Changes in levels of phosphorous (P), and (iso)flavonoids. High P levels can induce some defense genes to express hydrogen peroxidase, chitinase, and glucanase. These gene products can repress colonization by AM fungi. The plant defense response regulatory effect for different (iso)flavonoids varies, and their levels are regulated by P. (5) The suppressed expression of symbiotic genes. Some symbiosis-related genes inhibit plant defense responses, but it is still unclear which mechanisms underlie gene regulation. We provide here a theoretical basis for research into AM symbiosis that may promote study of host plant resistance and the mechanisms of symbiosis formation.
We provide a deeper insight into the signal transduction pathways of mycorrhization that will aid understanding and analysis of plant defense mechanisms in the AM context. The on-going development of genome sequencing technology will contribute greatly to the detailed study of symbiosis-related genes, and pathogenesis-related protein genes. These related genes may be induced to express corresponding proteins, be repressed, postpone expression or even shutdown, or both may work together to form symbioses. Elucidation of these features will help us understand the roles that plant defenses play in mycorrhizal formation; providing an unprecedented opportunity for research into mycorrhizal molecular biology and the interaction of symbiotic partners, and allowing the underlying mechanisms to be gradually uncovered. -
Fu Xiaocheng, Tang Tao, Jiang Wanxiang, Li Fengqing, Wu Naicheng, Zhou Shuchan, Cai Qinghua
2008,28(1):45-52, DOI: 10.1016/S1872-2032(08)60019-0
Abstract:
The influence of small hydropower plants (SHPs) on the spatial distribution of macroinvertebrate assemblages was investigated in 5 cascade SHPs along the Xiangxi River in October 2005. 5 sites were sampled at each SHP. A total of 4656 macroinvertebrates belonging to 69 genera were collected. The characteristics of macroinvertebrate community structures were analyzed by using richness, abundance, dominant species and functional feeding groups. The results suggested that construction of SHPs had no significant impact on water chemistry, but on physical variables (such as current velocity and water depth) which varied significantly among the 5 sites. All the characteristics of the macroinvertebrate community were more or less affected by the construction, especially by the abundance, filter-collector percentage, predator percentage, and the stations. The results also suggested that the sites beneath the dam had the most different community structures, indicating that diverting the water current completely is harmful to the protection of macroinvertebrate diversity of the river.
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2008,28(3):1257-1269, DOI: 10.1016/S1872-2032(08)60039-6
Abstract:
Wood borers are important forest insect pests and difficult to be controlled owing to their concealed behavior. However, parasitic wasps can effectively ascertain and parasitize wood borers as well as other concealed pests by using special searching, finding and attacking mechanisms, which have been developed during the course of long-term coevolution with their hosts. The present paper summarizes the behavioral mechanisms of parasitic wasps involved in searching and locating their concealed hosts. Parasitic wasps can accurately find the location of their hidden hosts and then parasitize them, usually by using olfactory semiochemicals from hosts (lavare and adults), host frass and symbiotic microorganisms in host galleries; visual signals from color contrast of plant surface; contact stimuli from characters of host physical defense; substrate vibrations produced by host feeding and movement; infrared radiation from host activities and metabolizability. Some parasitic wasps may integrate the information of several stimuli from different sources to enhance the reliability and accuracy of host locations. In addition, the potentials for utilizing the host location signals of parasitoids in biological control are discussed.
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Jiang Zhibing, Huang Yijun, Xu Xiaoqun, Liao Yibo, Shou Lu, Liu Jingjing, Chen Quanzhen, Zeng Jiangning
2010,30(1):8-15, DOI: 10.1016/j.chnaes.2009.12.002
Abstract:
Recently, the impact of petroleum pollution on marine plankton has been complemented by a great concern. This review summarizes the reports about toxic effects of oil water accommodated fraction (WAF) on marine phytoplankton, zooplankton and early life stage of animal. For the oil WAF, toxicants are mainly composed of the aromatic hydrocarbons, such as the benzene hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) with 2–5 rings. The oil WAF, especially the PAHs, can be accumulated in plankton due to their great lipophilic abilities, and thus elicites various deleterious effects. Toxicological tests show that marine plankton is very sensitive to the petroleum WAF, as the order of median effective/lethal concentration is merely μg/L or mg/L. There are species and developmental stages differences of plankton tolerance to petroleum WAF, and the toxicity of different oil WAF is various. Generally, its toxicity enhances with increasing carbonic chain length and benzene ring number. Many studies on the acute and sub-acute toxic effects of oil WAF have been done, however few researches on its chronic toxic effects has been carried out till now. Besides, most reports focused on the levels from molecule to individual, though very little work of petroleum toxic effects has ever been performed on the marine plankton population or community levels. Therefore, it is necessary to continue these studies in future.
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Wang Yunxia, Michael Frei, Song Qiling, Yang Lianxin
2011,31(6):277-282, DOI: 10.1016/j.chnaes.2011.09.006
Abstract:
Global atmospheric carbon dioxide concentration ([CO2]) is increasing rapidly. The Intergovernmental Panel on Climate Change estimated that atmospheric [CO2] has risen from approximately 280 μmol mol-1 in pre-industrial times to approximately 381 μmol mol-1 at present and will reach 550 μmol mol-1 by 2050. In the absence of strict emission controls, atmospheric [CO2] is likely to reach 730–1020 μmol mol-1 by 2100. Rising atmospheric [CO2] is the primary driver of global warming, but as the principal substrate for photosynthesis it also directly affects the yield and quality of crops. Food quality is receiving much more attentions recently, however, compared with grain yield, our understanding in the response of grain quality to elevated [CO2] is very limited. Rice (Oryza sativa L.) is one of the most important crops in the world and the first staple food in Asia, providing nutrition to a large proportion of the world’s population. Elevated [CO2] leads to numerous physiological changes in rice crops, such as changes in the photosynthesis and assimilate translocation, nutrient uptake and translocation, water relation, and altered gene expression and enzyme activity. These altered processes are very likely to affect the chemical and physical characteristics of rice grains. In this review, we first describe main characteristics of rice grain quality, and then summarize findings in literature related to the impact of elevated [CO2] on grain quality falling into four categories: processing quality, appearance, cooking and eating quality, and nutritional quality, as well as the possible mechanisms responsible for the observed impacts. Elevated [CO2] caused serious deterioration of processing suitability, in particular, head rice percentage was significantly decreased. In most cases, elevated [CO2] increased chalkiness of rice grains. The evaluation of physicochemical characteristics together with starch Rapid Visco Analyser (RVA) properties indicated no change or small changes in cooking and eating quality under elevated [CO2], and these changes could not be detected by sensory taste panel evaluation. Elevated [CO2] significantly decreased nitrogen or protein concentration in rice grains, while in most cases other macro- and micro-nutrients showed no change or decrease in concentration. In addition, the responses of rice quality to elevated [CO2] might be modified by varieties, applied fertilizer rates or gas fumigation methodologies. The available information in the literature indicates a clear tendency of quality deterioration and thus lower commercial value for rice grains grown under a projected high CO2 environment. Understanding the factors causing quality deterioration in rice and the related biological mechanisms might be the utmost important scientific theme in future research. Here we also discuss the necessity of formulating adaptation strategies for rice production in future atmospheric environments, nevertheless, the increase in yield, the improvement in quality and stress resistance of rice should be combined and integrated into the adaptation approaches. Compared with enclosure studies, the field experiments using Free-Air CO2 Enrichment (FACE) system provide sufficient experimental space and the most realistic mimic of a future high CO2 atmosphere, and give scientists perhaps the best opportunity to achieve multiple goals.
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Gong Minggui, Tang Ming, Zhang Qiaoming, Feng Xinxin
2012,32(2):62-67, DOI: 10.1016/j.chnaes.2011.12.005
Abstract:
In order to investigate the effects of climatic and edaphic factors on arbuscular mycorrhizal (AM) fungi in the rhizosphere of Hippophae rhamnoides in the Loess Plateau, spore density, mycorrhizal colonization and gene diversity were analyzed by using the methods of microscopy and polymerase chain reactiondenaturing gradient gel electrophoresis (PCR-DGGE) respectively. The results showed that H. rhamnoides could form strong symbiotic relationships with AM fungi. There existed obvious differences in AM fungal colonization among five sampling sites in the Loess Plateau (P < 0.05). Correlation analysis showed that AM fungal colonization and spore density were closely related with climatic and edaphic factors. 42 different species (band types) were found in the DGGE gel. Based on analysing the position and intensity of AM fungal DGGE bands, the gene diversity indices, including species richness, evenness, Simpsom’s and Shannon-Weiner index, showed significant differences among five sampling sites (P < 0.05). All the AM species could be classified into four groups in the biplot of canonical correspondence analysis (CCA), and each group had various responses to climatic and edaphic factors. Monte Carlo random test indicated that soil available phosphorus (F = 2.26, P = 0.025) and spore density (F = 1.76, P = 0.006) were the dominating factors affecting AM fungal communities. In conclusion, AM fungal colonization and community diversity in the rhizosphere of H. rhamnoides showed obvious spatial heterogeneity among the different areas of the Loess Plateau, and climatic and edaphic conditions were important factors affecting the AM fungal communities. Therefore, screening and application of AM fungal strains in the Loess Plateau need to fully consider the local climatic and edaphic conditions.
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2009,29(4):237-243, DOI: 10.1016/j.chnaes.2009.08.006
Abstract:
Robinia pseudoacacia is a North American species and in Poland it is currently invasive in character. It is used to recultivate sand excavations and others, most often in order to make the process of plant and soil succession more advanced. It has been observed that in places were R. pseudoacacia dominated in plantations, the herbaceous vegetation under the trees is poor and sometimes other vascular plants are not appearing at all. Plants usually overgrow the space out of the canopy shade. The positive influence of R. pseudoacacia on a habitat is primarily connected with the chemical composition of plant litter, as well as with the biology of the species. Chemical composition of R. pseudoacacia litter has been researched. The greatest accumulation of elements has been observed in the following parts: green leaves (Ca > K > Mg > P > Si > Na > Fe > Zn > Al > Mn) and leaf litter (Ca > K > Mg > Si > Fe > P > Na > Al > Zn > Mn). Similar regularities are observed in the remaining litter of R. pseudoacacia. It must be emphasized that nitrogen occurs in similar quantities in particular samples and it varies from 1.01 to 2.65%. The plant litter reaction (pH) vary from acid to weakly acid. In a short period of time under the canopy of R. pseudoacacia a 10 cm organic and humus horizont (O/A) has developed.
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Ren Xiaolong, Jia Zhikuan, Chen Xiaoli, Han Qingfang, Li Rong
2008,28(3):1006-1015, DOI: 10.1016/S1872-2032(08)60034-7
Abstract:
A field experiment was conducted to determine the effects of a rainwater-harvesting furrow/ridge system (RHFRS) on water use efficiency (WUE) and grain yield of spring com in different simulated rainfall treatments. Our results showed that when rainfall supply ranged between 230 and 440 mm, the rainwater-harvesting furrow/ridge system increased surface temperature by 0.7–1°C at the depth of 10 cm and increased soil water storage by 5%–12% in the soil layer of 0–120 cm compared with the control. Emergence was also more rapid in the furrow-ridge system. Spring corn yield in the rainwater-harvesting furrow/ridge system was 83% higher in the 230 mm rainfall treatment, 43% higher in the 340 mm rainfall treatment, and 11% higher in the 440 mm rainfall treatment compared with the control. Similarly, WUE was 77% higher in the 230 mm rainfall treatment, 43% higher in the 340 mm treatment, and 10% higher in the 440 mm treatment than those of the control under the corresponding rainfalls. In summary, results from this study indicate that 440 mm rainfall during the spring corn growing season is the upper limit for which the rainwater-harvesting furrow/ridge system should be adopted.+
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Ye Le, Yang Shengyun, Zhu Xiaoming, Liu Min, Lin Jingyi, Wu Kaichang
2011,31(5):241-245, DOI: 10.1016/j.chnaes.2011.06.003
Abstract:
To understand the physiological and ecological responses of marine fishes to the change of water temperature, newly-hatched larvae of Yellowtail clownfish Amphiprion clarkii were reared in captivity at water temperatures of 23, 26 and 29 °C till they completed the metamorphosis to juvenile phase, and larval survival, development, growth and feeding were evaluated during the experimental period. The results showed that water temperature influenced the physiological performance of larvae of A. clarkii significantly. The survival and growth rates of larvae of A. clarkii increased significantly with the increase of water temperature from 23 to 29 °C (P < 0.05). Water temperature also influenced larval development of A. clarkii significantly and larvae reared at 23 °C took longer time for post-larval development and metamorphosis compared to 26 and 29 °C (P < 0.05). Total length and body weight for post-larval development and metamorphosis decreased with the increase of water temperature from 23 to 29 °C (P < 0.05). Q10 in developmental rate was higher than in daily growth rate at the same rearing temperature, indicating that at water temperature had greater influence on larval development than on growth. Water temperature also influenced larval feeding of A. clarkii significantly with feed ration (FR) and feed conversion efficiency (FCE) increased with the increase of water temperature from 23 to 29 °C (P < 0.05). There was a positive correlation between FR and specific growth rate (SGR) (P < 0.05) but not between FCE and SGR (P > 0.05), indicating that FR influenced growth rate significantly in larvae of A. clarkii. This study demonstrated that the physiological responses of larvae of A. clarkii to the change of water temperature and confirmed that water temperature influenced larval survival, development, growth and feeding significantly. This study suggests that the decline of larval survival and growth rates, extension of pelagic larval duration and reduction of larval feeding at lower temperature have ecological impacts on larval dispersal and metamorphosis, juvenile settlement and population replenishment in A. clarkii in the wild.
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Yan Yunrong, Chen Junlan, Lu Huosheng, Hou Gang, Lai Jinyang
2012,32(1):18-25, DOI: 10.1016/j.chnaes.2011.04.008
Abstract:
The monthly and ontogenetic variations in diet of hairtail Trichiurus margarites Li (1992) [20] (Perciformes, Trichiuridae) were examined in the Beibu Gulf of the South China Sea from October 2008 to September 2009. Stomachs of 666 hairtail ranging in size from 121 mm to 561 mm pre-anal length (PL) were sampled monthly from commercial fish catches. Fish were the primary prey, with Decapterus maruadsi (Perciformes, Carangidae) averaging 23% by number, 34% by weight, and 49% by Index of Relative Importance (IRI). Other important prey in the diet included the small benthic fish, Bregmaceros rarisquamosus and Bregmaceros nectabanus (Gadiformes, Bregmaceroridae) and the decapod shrimp, Acetes chinensis, with IRI percentages of 8%, 4%, and 3%, respectively. Low rates of cannibalism and predation on 30 additional species of prey were observed. Trophic diversity (Brillouin Index, Hz) was moderate throughout the year. Mean feeding intensity (Repletion Index, RI) varied considerably by month and increased with the gonad maturity stages of hairtail; conversely, the proportion of empty stomachs decreased with maturity stages, from 60.9% empty at Stage I to 41.6% empty at Stage VI. Prey weight and numbers differed significantly among the 14 PL size classes and increased with body size. Cluster analysis of prey IRI values also indicated differences in the feeding habits of hairtail by size class. Understanding the monthly and ontogenetic changes in hairtail diet may assist in the development and improvement of marine ecosystem modeling for the Beibu Gulf, South China Sea.
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Duan Xiaonan, Wang Xiaoke, Fei Lu, Ouyang Zhiyun
2008,28(2):463-469, DOI: 10.1016/S1872-2032(08)60025-6
Abstract:
As one of the important ecosystem services of wetlands, carbon sequestration potential of lakes and swamps in China were investigated. Significant differences were found among the carbon sequestration potential of various lakes, determined by natural conditions and human disturbance. In this study, swamps had a carbon sequestration potential of 4.90 TgC, much higher than lakes in China. Mangrove and coastal marsh have the highest carbon sediment rate among swamps. Carbon sequestration potential in returning farms to lakes and swamps was 30.26 and 0.22 GgC·a-1, respectively. Under the ongoing national wetland conservation action plan in China, the carbon sequestration potential of wetland restoration was 6.57 GgC·a-1. Protection and restoration measurements can improve carbon sequestration potential of wetlands.
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Chen Jin, Deng Xiaobao, Zhang Ling, Bai Zhilin
2006,26(2):309-316, DOI: 10.1016/S1872-2032(06)60006-1
Abstract:
The composition of the diet and the foraging ecology of the Asian elephant in its natural habitat were studied from 1998 to 2000 in the Shangyong National Natural Reserve located at Xishuangbanna, China, using field observation and dung analysis. A total of 106 plant species were recorded as being eaten by Asian elephants, 83 of which were identified in the elephants' dung. The plant families that contributed to a major proportion of the elephants' diet in the study area were: Gramineae (8 spp., 10.0%), Moraceae (7 spp., 9.9%), Papilionaceae (4 spp., 8.4%), Araliaceae (3 spp., 6.6%), Vitaceae (3 spp., 5.7%), Apocynaceae (3 spp., 4.6%), Musaceae (1 spp., 4.2%), Zingiberaceae (3 spp., 3.7%), Myrsinaceae (3 spp., 3.6%), Rosaceae (3 spp., 3.6%), Euphorbiaceae (5 spp., 3.3%), Ulmaceae (2 spp., 3.0%) and Mimosaceae (4 spp., 2.9%). The most important plants in the elephants' diet were Ficus spp. (Moraceae, 9.0%), Dendrocalamus spp. (Gramineae, 4.5%), Musa acuminata (Musaceae, 4.2%), Microstegium ciliatum (Gramineae, 3.5%) and Amalocalyx yunnanensis (Apocynaceae, 3.1%). Asian elephants consumed a variety of plants in terms of life forms, including trees, vines, shrubs and herbs. Early successional plant species constitute a higher proportion of the diet than late successional plants (42 spp. taking 59% vs. 32 spp. taking 37%). Browsing species accounted for a larger proportion of the diet compared to grazing species (77 spp. taking 91% vs. 6 spp. taking 9%). The number of plant taxa (species, genus, family) in elephants' diet each month negatively correlated with monthly rainfall and mean temperature. The study may help to develop proper strategies for wildlife management especially with regard to the human-elephant conflict, which is now a serious issue in the conservation of Asian elephants in this area.
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Xing Guangxi, Zhao Xu, Xiong Zhengqin, Yan Xiaoyuan, Xu Hua, Xie Yingxin, Shi Shulian
2009,29(1):45-50, DOI: 10.1016/j.chnaes.2009.04.006
Abstract:
The main research results of nitrous oxide (N2O) emission from paddy fields in China were summarized. Paddy fields are an important source of N2O emission. Denitrification process exists not only in the upper flooded cultivated layer in paddy fields but also in the underground saturated soil layer. The cropping system with rice–wheat rotation and the water regime with mid-season aeration (MSA) in paddy fields of China are not only the controlling factors of N2O emission but also the main factors influencing methane (CH4) emission. There is a trade-off relationship between N2O and CH4 emissions from paddy fields. Straw amendment reduced N2O emission but promoted CH4 emission. Therefore, effects of both CH4 and N2O emissions from rice fields on the global warming potential (GWP) should be taken into consideration when any mitigation options are to be established.
