The fallacy of the missing middle: physics →…→ fisheries     

MICHAEL BAUMANN 《Fisheries Oceanography》1998,7(1):63-65

In this paper I discuss some of the shortcomings of today's marine science in response to a recently published paper by Ann Gargett (1997). Three problem areas have been identified in the field linking climate forcing and fish production: First, the yet-to-be established observational proof for a relationship between the two; Second, the strongly neglected biology of organisms at evolutionary and ecological time scales; and thrird, the disregard for spatial and temporal scales in the discussion of mechanisms and supporting data.  相似文献   

不同生境柚园果熟期橘小实蝇诱捕效果及种群密度比较     

蓝木香  杨和生  许良政  刘惠娜  曾宪录 《广东农业科学》2020,47(10):120-125

【目的】掌握不同生境柚园果熟期橘小实蝇种群密度和活动规律，探索不同色板、不同方位和不同气温环境对橘小实蝇的诱捕效果。【方法】于 2019 年 9—11 月在两类不同生境柚园开展橘小实蝇监测诱捕试验。【结果】经单因素方差分析表明，自然生境柚园中亮黄板每板诱捕数量为 24.84（±1.90）头，示范标准柚园中为 4.29（±0.44）头，诱捕效果显著高于土黄板和蓝板，自然生境柚园诱捕数量显著高于示范标准柚园。自然生境柚园中南面色板诱捕数量为 12.01（±2.02）头，示范标准柚园为 2.52（±0.44）头，均较其他方位多。气温与规范管理柚园橘小实蝇种群密度呈一定程度的负相关。两类柚园 11 月诱捕数量显著高于 9 月和 10 月。【结论】亮黄色粘虫板对柚园橘小实蝇有明显的防治效果。在示范标准柚园果实成熟期应结合自然条件下橘小实蝇的种群变化规律提前做好预防工作，根据柚园生境因地制宜，综合治理。  相似文献   

西双版纳自然保护区鼷鹿生境选择的初步研究   总被引：2，自引：0，他引：2  

罗爱东  黄建国  董永华  宋金平  唐爱军  冯国庆 《西部林业科学》1999,(2)

对中国仅见于西双版纳勐腊县鼷鹿（ＴｒａｇｕｌｕｓｊａｖａｎｉｃｕｓｗｉｌｉａｍｓｏｎｉＫｌｏｓ）栖息地生境因子的调查分析，初步得出鼷鹿栖息环境与植被类型、下木、地被、坡度、坡向、海拔、土质的相关程度。对各生境因子的优先选择顺序分别为：下木郁闭度，地表覆盖物，坡度，植被类型，土质，海拔，坡向。并初步划分出鼷鹿的４个生境等级为：（１）最佳生境地；（２）良好生境地；（３）一般生境地；（４）劣等生境地。并在此基础上提出相应的保护对策。  相似文献   

Restoration of Gypsicolous Vegetation on Quarry Slopes: Guidance for Hydroseeding under Contrasting Inclination and Aspect     

《Land Degradation \u0026amp; Development》2017,28(7):2146-2154

The establishment of gypsicolous vegetation of high conservation value on land impacted by quarrying requires restoration measures to overcome constraints imposed by the new landforms created in the process. The aim of this study was to assess the suitability of three standard hydroseeding methods to restore gypsicolous vegetation on quarry spoil slopes under a dry Mediterranean climate. The treatments were as follows: paper cellulose mulch, paper cellulose mulch + organic blanket, and wood fibre mulch, compared against a control. These treatments were tested on two slopes (10–15% vs 60–65%) and two contrasting aspects (north vs south). We evaluated the cover of all plant species 2·8 years after treatment, assessing both target gypsicolous species and non‐target species. Our results showed strong compositional and cover differences between hydroseeded and control plots. Control plots had a low cover of target species with a vegetation composed of early‐successional species that had the potential to hinder target species establishment over time. All hydroseeding treatments improved target vegetation cover, with wood fibre performing best in most situations studied here, alternatives being the cheaper but less effective paper mulch on shallow slopes, or the more expensive paper mulch + blanket on steep slopes in case of high erosion risk. Shallow and southern‐steep slopes were more suitable for the recovery of gypsum vegetation by hydroseeding, compared to northern‐steep slopes where non‐target species developed more readily outcompeting target species. These results will help to guide management decisions to restore gypsicolous vegetation by hydroseeding in disturbed gypsum habitats. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Polar light regime and piscivory govern diel vertical migrations of planktivorous fish and zooplankton in a subarctic lake     

K. K. Kahilainen  T. Malinen  H. Lehtonen 《Ecology of Freshwater Fish》2009,18(3):481-490

Abstract –  Seasonal variation in light intensity has strong impacts on invertebrate and vertebrate habitat selection creating trade-offs between foraging gain and risk of death. Diel vertical migration (DVM) has received a particularly interest, but multitrophic level studies in lakes under polar light regime have not been conducted. Here, we examined habitat selection of pelagic zooplankton, planktivores and piscivores in subarctic Lake Muddusjärvi with polymorphic whitefish ( Coregonus lavaretus (L.)). Seasonal change in light was hypothesized to be the most important abiotic factor inducing DVM, whereas predation was considered as an ultimate biotic factor. During period of mid-night sun in June, no DVM was observed at any trophic level, whereas during normal day and night light in September planktivores and zooplankton migrated. DVM was top-down controlled, where piscivorous brown trout ( Salmo trutta L.) used pelagic habitat continuously inducing DVM of its main prey, pelagic whitefish morph, which cascaded to reverse DVM of zooplankton. Top-down control of lower trophic level DVMs by piscivores might be more general pattern in lakes than previously considered.  相似文献   

高山红景天的繁殖生态学研究 Ⅰ生态因子与植物学、物候学特性分析     

谭敦炎  朱建雯  田允温 《新疆农业大学学报》1997,(3)

本研究对生长在新疆天山１号冰川观测站附近的高山红景天，从生境土壤的理化性质、气象因子等方面进行了观测与统计，并对其植物学及物候学特性进行了较详细的观察，结果表明：高山红景天植株的形态特征、生长发育节律与其特殊的生态环境是相适应的。  相似文献   

壶瓶山自然保护区华南虎野外调查及栖息地评价   总被引：3，自引：0，他引：3  

黄祥云  胡德夫  唐小平  王志臣  刘伟石 《浙江林学院学报》2004,21(2):180-184

湖南省壶瓶山是森林和野生动物类型的国家级自然保护区,是近几年发现华南虎Panthera tigris amoyensis证据较多的区域.中美华南虎联合调查队于2001年10～12月采用访问调查法、样带调查法、痕迹调查法和红外线自动照相技术等目前国际国内通用的方法和技术,对该保护区进行了调查.此次调查虽未得到华南虎存在的确切证据,但较系统地调查了该区域的生境状况,初步评价了华南虎的生存环境.该区域历史上是华南虎分布较多的区域.经分析,目前仍具备华南虎生存的基本条件,是以后实施华南虎重引入工程较为理想的试验基地.表2参13  相似文献   

Habitat relationships with fish assemblages in minimally disturbed Great Plains regions     

J. R. Fischer  C. P. Paukert 《Ecology of Freshwater Fish》2008,17(4):597-609

Abstract – Effects of local environmental influences on the structure of fish assemblages were evaluated from 159 sites in two regions of the Great Plains with limited anthropogenic disturbance. These regions offered an opportunity to evaluate the structure and variation of streams and fish assemblages within the Great Plains. We used canonical correspondence analyses to determine the influence of environmental conditions on species abundances, species occurrences and assemblage characteristics. Analysis of regions separately indicated that similar environmental factors structured streams and fish assemblages, despite differences in environmental conditions and species composition between regions. Variance in fish abundance and assemblage characteristics from both regions was best explained by metrics of stream size and associated metrics (width, depth, conductivity and instream cover). Our results provide a framework and reference for conditions and assemblage structure in North American prairie streams.  相似文献   

莲花山自然保护区珍稀鸟类及其栖息地调查   总被引：1，自引：0，他引：1  

刘秀生  甘建民 《甘肃林业科技》2002,27(2):23-26

对莲花山自然保护区分布的珍稀鸟类及其栖息地进行了调查，并利用卫星影像资料分析了鸟类栖息地现状，表明该地区鸟类栖息地严重破碎化，严重威胁着保护区内珍稀鸟类的生存，提出了封山育林扩大保护区面积等加强珍稀鸟类保护的建议。  相似文献   

Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica III. Cycles of organic matter and nutrients     

H. W. Fassbender  L. Alpízar  J. Heuveldop  H. Fölster  G. Enríquez 《Agroforestry Systems》1988,6(1-3):49-62

Models for cycles for organic matter and nutrients element (N, P, K, Ca and Mg) are presented for the agroforestry systems of cacao (Theobroma cacao) withCordia alliodora orErythrina poeppigiana in Turrialba, Costa Rica. For the models, system reserves (soil, humus, vegetation divided into leaves, branches, stems, fine roots, fruits) and transference between compartments (production and decomposition of litter residues) inputs (fertilizer, rainfall) and outputs (harvests) of the system are considered. The implications of the models are discussed in detail. Aspects of net primary production in the systems studied are considered. N fixation is calculated on the basis of balances. Analysis of soil water showed high variations that coincided with rainfall patterns and pruning of theE. poeppigiana. For part I see Vol. 4, No. 3, 1986 For part II see this issue Agroforestry Project, CATIE/GTZ (Tropical Agricultural Research and Training Center/Gesellschaft für Technische Zusammenarbeit), Turrialba, Costa Rica  相似文献