水资源投入产出方法研究进展

从扩展建模技术、系数调整2条线索回顾国内外的水资源投入产出研究进展, 并讨论水资源的投入产出研究的不足和发展趋势。因为水资源投入产出表反映的是水资源与经济结构的关系,如果研究人员自己编制一张水资源投入产出表是不容易的事情。通常情况下都是以研究地域的投入产出表为基础,与其他模型相结合来研究水资源投入产出,但是水资源投入产出建模技术因为数据的限制而只能建立年度模型,具有很强的前提假定,使得投入产出建模技术缺乏灵活性,因而在运用中有对模型改进的必要。水资源投入产出扩展建模技术在这些方面就分别形成了与地区投入产出表结合的投入产出建模技术、与水资源供给相结合的投入产出扩展建模技术、与延长表结合的投入产出扩展建模技术。时效性缺乏一直就成为影响IO模型研究的最主要的瓶颈之一,为此,对各种用于建立新的 IO 表技术的研究一直受到普遍的重视。目前, IO 表系数调整方法已从消耗系数不变的系数调整方法、以RAS为代表的比例法, 发展到多种手段相结合的优化法。算法的改进和求解非线性规划问题的大量计算机软件的出现使得非线性优化模型得到了广泛的应用。     

天目山自然保护区银杏天然种群生命表

以种群生命表和生存分析理论为基础,采用空间代替时间法和分段匀滑技术,编制浙江天目山自然保护区银杏天然种群特定时间生命表,绘制其死亡率曲线、消失率曲线、存活曲线和生存函数曲线,分析种群数量动态变化.结果表明:银杏种群结构存在波动性,趋于Deevey Ⅱ型,其成年阶段的个体较丰富;银杏种群死亡率和消失率曲线变化趋势基本一致...     

山西历山国家级自然保护区千金榆群落种间分离研究

对山西历山国家级自然保护区普通沟和西峡的千金榆(Carpinus cordata)群落进行野外调查,共记录了40个样方,44个物种,组成946个种对.利用最近邻体法构造N×N最近邻体列联表,以x2检验和种间分离指数S作为区分指标,研究了千金榆群落的种间分离情况.结果表明:(1)946个种对中呈现随机毗邻的最多,有507个种对,占总数的53.59％;呈现正分离的有349个种对,占总数的36.89％;而呈现负分离种对最少,只有90对,占总数的9.52％.(2)群落的建群种或优势种因为有较强的生存能力和竞争能力,往往表现出正分离,例如千金榆、小叶鹅耳枥(Carpinus turczaninowii)、五角枫(Acer mono)、葛罗槭(Acer grosseri)等有较强生存能力的物种与大多数的物种发生正分离;而六道木(Abelia biflora)、东北茶镳子(Ribes mandshuricum)、小花溲疏(Deutziaparviflora),美蔷薇(Rosa bella)和紫花卫矛(Euonymus porphyries)等群落中的伴生种或小灌木,与部分物种形成负分离.其余物种之间发生随机毗邻的较多.(3)对千金榆群落44×44列联表进行全面分离,结果表明群落内的44个物种相互交错分布,不是全面分离.此外,种间分离的结果也揭示该群落处于演替初期,受岩石风化崩塌的影响较严重,人为干扰因素较轻.     

Restoration of managed pine fens: effect on hydrology and vegetation

Question: How does restoration affect the hydrology and the understorey vegetation of managed pine fens? Location: Oligotrophic pine fens in Natura 2000 areas in Kainuu, eastern Finland. Methods: Eleven managed pine fens and eight pristine reference pine fens were chosen for the study in 2005. The managed fens, which had been drained for forestry during the 1970s and 1980s, were restored in 2007. The water table was monitored in all fens over four growing seasons during 2006 to 2009, and vegetation was surveyed from permanent sample plots in 2006 and 2009. Results: Before restoration in 2006, the water table was at a significantly lower level in the managed fens compared with the pristine fens. Immediately after restoration, the water table rose to the same level as in the pristine fens, and this change was permanent. Forest drainage had had little impact on the understorey vegetation of the managed fens in the three decades before restoration, with species typical of pristine fens still dominating the sites. Forest dwarf shrubs and feather mosses had started to increase in cover, but mire dwarf shrubs and Sphagnum mosses still dominated the managed fens. Only the typical hollow species Sphagnum majus, Sphagnum balticum and Scheuzeria palustris were missing from the managed fens. Two years after restoration, the changes in species composition were also marginal, with increased cover of mire dwarf shrubs and sedges being the only significant change. Conclusions: The success of restoration of oligotrophic pine fens seems likely, given that changes in hydrological functioning occurred rapidly, and since little change has occurred in the vegetation composition after draining. Speeding up the regeneration process in these peatland types by restoration may, therefore, be recommended, especially if the drainage effect extends to nearby pristine mires and influences their biodiversity.     

Influence of diet on life table parameters of <Emphasis Type="Italic">Iphiseius degenerans</Emphasis> (Acari: Phytoseiidae)

Studies on the reproduction, longevity and life table parameters of Iphiseius degenerans (Berlese) were carried out under laboratory conditions of 25 ± 1 °C, 75 ± 5% RH and 16L:8D h. As food sources for the predatory mite, Ricinus communis L. pollen, all stages of the spider mite Tetranychus urticae Koch, Frankliniella occidentalis (Pergande) larvae, and Ephestia kuehniella Zeller eggs were selected. All diets were accepted as food by the adult mites. Female longevity ranged from 29.5 to 42.4 days, the highest value was recorded on a diet of Ephestia eggs. The highest percentage of females escaping the experimental arena was observed on the diet consisting of thrips larvae. The highest oviposition rate (1.9 eggs/female.day) was recorded when the predator was fed on spider mites on an artificial substrate. For other diets, oviposition rates ranged from 1.0 to 1.3 eggs/female.day. The intrinsic rate of natural increase (r _m) of I. degenerans varied between 0.015 and 0.142 females/female.day. The diet consisting of castor bean pollen resulted in the highest population growth whereas the diet on spider mites brushed off onto a bean leaf arena resulted in the slowest population growth. This can be explained by the inability of the predator to cope with the webbing of T. urticae, and the high escape rate of the progeny when reared on spider mites. The percentage of females in the offspring ranged from 40 to 73%.This revised version was published online in May 2005 with a corrected cover date.     

Impacts of biological control and invasive species on a non-target native Hawaiian insect

The potential for classical biological control to cause unintended harm to native species was evaluated in the case of the endemic Hawaiian koa bug, Coleotichus blackburniae White (Hemiptera: Scutelleridae), and parasitoids introduced to Hawaii for control of an agricultural pest, the southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae). Parasitism of C. blackburniae eggs, nymphs and adults by biocontrol agents was quantified across a wide range of habitats and compared to other sources of mortality. Egg mortality due to the biocontrol agent Trissolcus basalis Wollaston (Hymenoptera: Scelionidae) was low (maximum 26%) and confined to elevations below 500 m on a single host plant. Predation, mainly by alien spiders and ants, was the greatest source of egg mortality (maximum 87%). Parasitism of adult C. blackburniae by the biocontrol agent Trichopoda pilipes (F.) (Diptera: Tachinidae) was near zero at 21 of 24 sites surveyed. Three sites with high bug density had higher levels of T. pilipes parasitism, reaching maxima of 70% among adult female bugs, 100% among males and 50% among fifth instars. Male-biased parasitism indicated that T. pilipes is adapted to using male aggregation pheromone for finding C. blackburniae hosts. The relative impacts of biocontrol agents and other sources of mortality were compared using life tables. Invasive species, particularly generalist egg predators, had the greatest impacts on C. blackburniae populations. Effects of intentionally introduced parasitoids were relatively minor, although the tachinid T. pilipes showed potential for large impacts at individual sites. In retrospect, non-target attacks by biological control agents on C. blackburniae were predictable, but the environmental range and magnitude of impacts would have been difficult to foresee.     

Porosity and available water of temporarily waterlogged soils in a Quercus robur (L.) declining stand

Pedunculate oak (Quercus robur L.) is particularly sensitive to decline in clayey soils presenting a high-perched temporary water table. These soils induce two successive constraints in one-year cycle: water excess (and hypoxy) in winter and early spring, and water shortage in summer (water stress being more restrictive to oak). We determined the porosity and water properties of temporarily waterlogged clayey soils supporting forest stands of decliningQuercus robur trees in a 101yr-old oak stand in Belgium (50°06N, 4°16E). Roots unevenly colonized the soil down to 1.6m: fine roots (diameter<5mm) were mostly distributed on the surface horizons (0–0.3 m) and around 1.3m deep, despite dense clayey horizons appearing at 0.35m depth. Clay content below this depth reached 46–51. Illite and vermiculite were the dominant clay minerals. The clayey horizons exhibited marked shrink–swell properties: bulk density at 30kPa increased from 1.41 to 1.88gcm^–3 from the surface to 2m depth. There was also evidence of hypoxic conditions caused by water saturation of pore space in the rooting zone from October to mid-April. Extractable water (EW), calculated between moisture tensions of 5 and 1600kPa was 152.8mm. The level of perched temporary water table strongly depended on the seasonal rhythm of water uptake by trees and on the shrink–swell behaviour of soil.     

New similarity indices for the assignment of relevés to the vegetation units of an existing phytosociological classification

Every proposed vegetation classification is sooner or later confronted with an accumulation of new data, which has to be assigned to existing vegetation units. Calculation of similarity indices between new relevés (vegetation plots) and constancy columns of established vegetation units is a suitable method for computerised assignment of relevés to these units. This paper compares several similarity indices using simulated data set where either randomly distributed or diagnostic species prevail in the species composition of the tested relevé. Traditional indices, based only on species composition, produce different results than similarity indices that consider species fidelity. However, both types of indices failed in some situations and thus cannot be widely accepted as suitable methods of additional relevé assignment. Therefore a combined Frequency-Positive Fidelity Index (FPFI) is proposed. This new index includes compositional similarity of an assigned relevé with vegetation unit and retains the advantages and lacks the disadvantages of tested indices. The calculation of all these indices is available in the JUICE program (http://www.sci.muni.cz/botany/juice.htm).     

新疆褐家鼠种群生命表及其在干旱区的生存能力分析

从2000年至今,曾于野外捕捉的褐家鼠3 837只,其中雌鼠2 685只,雄鼠1 152只,经鉴定划分为幼年组(Ⅰ)、亚成年组(Ⅱ)、成年Ⅰ组(Ⅲ)、成年Ⅱ组Ⅳ、老年组(Ⅴ)等5个年龄组,其年龄结构探讨种群数量动态,结果表明,种群中Ⅱ龄的平均生命期望值最高1.0357,其次为Ⅲ龄0.9488。该种群中1龄个体占优势地位,种群属于增长性种群,种群内禀增长率rm为0.2789/年,年周限增长率λ为1.3217,世代时间T为2.623年,种群经一世代的净增殖率R0为2.0782。     

Life history, life table, habitat, and conservation of Byasa impediens (Lepidoptera: Papilionidae)

This article investigates the biology of Byasa impediens, presenting its life-table data and analyzing its habitat requirements and the key factors threatening the survival of this species. This study also aims to detect specific protection methods to guarantee the long-term survival of Byasa impediens in Baishuijiang Reserve. Byasa impediens is bivoltine in Baishuijiang Reserve. The pupae overwinter on shrubs or on branches of trees. The eclosion of the first generation starts in mid-April. The adults of the first generation emerge in large numbers in mid-late May, and the second generation emerges from late June to mid-July. The two generations overlap. The adult males emerge 7–10 days earlier than the adult females. Their flight behavior is determined by factors such as perching along small rivers and gullies, and visiting flowers. The males are strong fliers. On the contrary, the flying ability of the females is weak; therefore, they just visit flowers, mate, and lay eggs near the natal area. The ratio of female to male is 1:4.1. The maximum lifespan of the males is 26 days, with an average of 6.9 days, whereas the maximum lifespan of the females is 21 days, with an average of 7.6 days. The pregnant eggs per female are 31.5 on average. The incubation period of the first generation is 12–14 days, whereas that of the second generation is 7–9 days. The larvae feed mainly on Aristolochia heterophylla. The larval period of the first generation lasts for 30 days with five instars and that of the second generation lasts for 30–40 days with five or six instars. The pupal period of the first generation begins in early June and lasts for 20–26 days whereas for the second generation, it begins between late July and late September. The adults prefer the following nectar plants: Albizzia julibrissin, Bauhinia glauca, Clerodendrum bungei, and Sambucus chinensis. The plant Aristolochia heterophylla is distributed at an altitude of 900–1680 m, and the most suitable range is 1200–1500 m. The host plants grow mainly along the paths and along the borders of forests where the canopy is rather open and shrubby undergrowth is found. The plant can hardly be found when the canopy density of the forest is greater than 80%. The elevation range most suitable for the larvae is 1200–1500 m. The ideal habitat of host plants also seems to be the ideal habitat of Byasa impediens. The key factors that adversely affect the population of Byasa impediens are loss and deterioration of habitats. The loss and deterioration of the habitats result in a decrease in the numbers of host plants and a more restricted distribution of the potential habitats. The habitat is easily influenced by anthropogenic activities, such as herding, cultivating, and using pesticides, which in turn influences the growth of the host plant Aristolochia heterophylla and the larvae of butterflies. Abnormal climatic conditions and natural enemies are the key factors affecting population density. The hot and dry weather in summer and the heavy rain in autumn considerably reduce the survival rate of eggs and larvae. The ichneumon parasitoids reduce the survival rate of the over-wintering pupae. The primary natural enemies of the larvae include spiders, earwigs, wasps, bugs, and ichneumon parasitoids. Other natural enemies of pupae and adults are birds. The most important conservation measures are preservation and reconstruction of the natural habitat, which includes rebuilding forests, enhancing management, enforcing existing laws, and developing eco-tourism. Creating a core-patch near all patches at a central area is also an important measure for conservation. In the most ideal habitat, appropriate shrub cutting can increase the growth of host plants, thereby promoting expansion of the Byasa impediens population.