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991.
Elizabeth H. M. Tyler Paul J. Somerfield Edward Vanden Berghe Julie Bremner Emma Jackson Olivia Langmead Maria Lourdes D. Palomares Thomas J. Webb 《Global Ecology and Biogeography》2012,21(9):922-934
Aim Ecologists seeking to describe patterns at ever larger scales require compilations of data on the global abundance and distribution of species. Comparable compilations of biological data are needed to elucidate the mechanisms behind these patterns, but have received far less attention. We assess the availability of biological data across an entire assemblage: the well‐documented demersal marine fauna of the United Kingdom. We also test whether data availability for a species depends on its taxonomic group, maximum body size, the number of times it has been recorded in a global biogeographic database, or its commercial and conservation importance. Location Seas of the United Kingdom. Methods We defined a demersal marine fauna of 973 species from 15 phyla and 40 classes using five extensive surveys around the British Isles. We then quantified the availability of data on eight key biological traits (termed biological knowledge) for each species from online databases. Relationships between biological knowledge and our predictors were tested with generalized linear models. Results Full data on eight fundamental biological traits exist for only 9% (n= 88) of the UK demersal marine fauna, and 20% of species completely lack data. Clear trends in our knowledge exist: fish (median biological knowledge score = six traits) are much better known than invertebrates (one trait). Biological knowledge increases with biogeographic knowledge and (to a lesser extent) with body size, and is greater in species that are commercially exploited or of conservation concern. Main conclusions Our analysis reveals deep ignorance of the basic biology of a well‐studied fauna, highlighting the need for far greater efforts to compile biological trait data. Clear biases in our knowledge, relating to how well sampled or ‘important’ species are suggests that caution is required in extrapolating small subsets of biologically well‐known species to ecosystem‐level studies. 相似文献
992.
森林生态系统中的养分循环是该系统的主要功能之一 ,历来为许多研究者所重视[1,4 ,5] 。磷是植物生长发育所不可缺少的重要营养元素 ,它对促进林木生长 ,提高林业生产力具有很大作用。以往有关森林生态系统磷素循环的研究 ,大多忽视了根系凋落归还的作用 ,从而影响循环结果及其相应评价。为此 ,研究了苏南丘陵次生栎林生态系统磷素循环 ,并进行系统分析 ,建立生态系统磷素动态模型 ,预测并分析其变化规律 ,为制定合理的经营管理措施 ,保持林业持续发展提供理论依据。1 自然概况与研究方法1.1 自然概况试验地位于江苏省句容县境内 ,东经119… 相似文献
993.
Taking a recent column by Braden Allenby in this journal as a starting point, we argue the need for researchers in the field of industrial ecology to reflect upon its normative aspects. We argue that the field will advance through an explicit discourse on such issues as epistemological positions, the inherent normative nature of using metaphors, and the way in which the field of study relates to the field of practice.
In "Culture and Industrial Ecology," Allenby raises, and begins to address, some critical questions that define the field of industrial ecology. We suggest that his arguments dismiss too lightly issues that are central to this developing field. The purpose of this reply is to open up for further discussion what industrial ecology is, and what it is not.
We begin by summarizing Allenby's line of reasoning. We explore his arguments around the notion of objectivity and the questions he raises about the relationship among objective science, normative positions, opinions, and fads. While Allenby makes a strong plea for industrial ecology to maintain objectivity and avoid normative positions, we contend that any positions on what should or should not be included in a field of study carry normative intent. Although science might seek to be objective in its method, scientists are rarely free of such normative positions. These positions need to be explicit and open to debate. Also, Allenby's position implies that industrial ecology as a field of study should be separated from industrial ecology as a field of practice. We argue that the interrelation of these fields provides important advantages.
Our main concern is that Allenby's position forestalls discussion on important issues at the heart of the field of study. We examine some key issues around the concept of objectivity and propose an agenda for research on the cultural and ideological aspects of industrial ecology. 相似文献
In "Culture and Industrial Ecology," Allenby raises, and begins to address, some critical questions that define the field of industrial ecology. We suggest that his arguments dismiss too lightly issues that are central to this developing field. The purpose of this reply is to open up for further discussion what industrial ecology is, and what it is not.
We begin by summarizing Allenby's line of reasoning. We explore his arguments around the notion of objectivity and the questions he raises about the relationship among objective science, normative positions, opinions, and fads. While Allenby makes a strong plea for industrial ecology to maintain objectivity and avoid normative positions, we contend that any positions on what should or should not be included in a field of study carry normative intent. Although science might seek to be objective in its method, scientists are rarely free of such normative positions. These positions need to be explicit and open to debate. Also, Allenby's position implies that industrial ecology as a field of study should be separated from industrial ecology as a field of practice. We argue that the interrelation of these fields provides important advantages.
Our main concern is that Allenby's position forestalls discussion on important issues at the heart of the field of study. We examine some key issues around the concept of objectivity and propose an agenda for research on the cultural and ideological aspects of industrial ecology. 相似文献
994.
Land-Use History in Ecosystem Restoration: A 40-Year Study in the Prairie-Forest Ecotone 总被引:4,自引:0,他引:4
W. Dean Kettle Paul M. Rich Kelly Kindscher Galen L. Pittman Pinde Fu 《Restoration Ecology》2000,8(3):307-317
Land‐use history, recent management, and landscape position influence vegetation at the Rockefeller Experimental Tract (RET), a 40‐year‐old restoration experiment in northeast Kansas. RET is representative of the prairie‐forest ecotone, containing native tallgrass prairie and oak‐hickory forest, but unique in having tracts of replanted prairie, seeded in 1957, that have undergone long‐term restoration treatments: burned, grazed, mowed, or untreated. A land‐use history database for RET was compiled using a geographic information system to integrate historic and contemporary sources of information. Restoration management on the reseeded prairie has had a profound effect on forest development: mowing or burning precluded forest establishment (<3% forest cover), whereas portions of untreated or grazed areas became heavily forested (>97% forest cover). Forest colonization depends upon biotic and edaphic conditions at the time restoration was initiated: for areas replanted to prairie and managed by grazing, forestation was 6% on land in cultivation prior to replanting, 20% on former pastureland, and 98% on land deforested just before replanting. Patterns of forest colonization were also significantly associated with three landscape positions: near existing forest, along water courses, and along ridge tops. Additionally, land‐use history analyses showed that the presence of various prairie and forest species resulted from persistence and not from colonization following restoration. Because of the lasting imprint of historic land use on the landscape, our results indicate that it is essential that restoration studies be evaluated within a site‐specific historical context. 相似文献
995.
本文在生物生产力研究的基础之上,通过热值测定,对东北东部帽儿山地区21年生人工落叶松(Larix gmelinii)生态系统净初级生产力形成过程中的能量特征做了系统研究。结果表明:(1)植物热值随植物种类、器官、分布层次、年龄及季节而发生变化。(2)生态系统中活植物体的能量现存量为269.719×1010J/ha,而枯死体中的能量现存量为36.817×1010J/ha,其中凋落物层和立枯体中能量贮量各占84.04%和15.96%。 (3)生态系统能量净固定量为264.346×109J/ha·yr,其中29.49%的能量存留在植物体中,用于植物净生长。生态系统年能量归还量为88.809×109J/ha,其中32.39%的能量在当年被分解释放,余下能量积累于凋落物层之中;生态系统的能量转化效率为2.299%,与其它森林植物群落相比,落叶松人工林系统是高效率的能量代谢系统。 相似文献
996.
激光扫描共聚焦显微镜与普通光学显微镜相比,其分辨率高,同时具有可对样品进行非侵入性无损伤断层扫描,以及对样品形貌进行三维成建等特点,因此,可作为研究晶体生长强有利的工具。本文介绍了其在定量测量晶体的个数,重组三维图像以获得晶体生长的过程信息及测定晶体生长台阶动态变化等方面的应用。还对激光扫描共聚焦显微镜在晶体生长研究的其它方面应用前景作了展望。 相似文献
997.
The release of N2O from the snow surface in winter and the soil in summer was measured in ten types of temperate ecosystems (bare ground, grassland, forest, marsh, and crop field) in Japan. The snow-covered crop field emitted by far the largest amount of N2O during the winter. Among the snow-covered natural ecosystems studied, marshy ecosystems showed the largest effluxes of N2O. Based on results showing that the magnitude of the winter N2O fluxes was not negligible compared with that of the summer N2O fluxes and because the snow period in the areas studied area is sufficiently long, we suggest that the winter N2O fluxes contribute significantly to the annual emission of N2O in the study areas. 相似文献
998.
Our objective was to determine how varied is the response of C cycling to temperature and irradiance in tundra vegetation. We used a large chamber to measure C exchange
at 23 locations within a small arctic catchment in Alaska during summer 2003 and 2004. At each location, we determined light
response curves of C exchange using shade cloths, twice during a growing season. We used data to fit a simple photosynthesis-irradiance,
respiration-temperature model, with four parameters. We used a maximum likelihood technique to determine the acceptable parameter
space for each light curve, given measurement uncertainty. We then explored which sites and time periods had parameter sets
in common—an indication of functional similarity. We found that seven distinct parameter sets were required to explain observed
C flux responses to temperature and light variation at all sites and time periods. The variation in estimated maximum photosynthetic
rate (Pmax) was strongly correlated with measurements of site leaf area index (LAI). The behavior of tussock tundra sites, the dominant
vegetation of arctic tundra, could largely be described with a single parameter set, with a Pmax of 9.7 μmol m−2 s−1. Tussock tundra sites had, correspondingly, similar LAI (mean = 0.66). Non-tussock sites (for example, sedge and shrub tundras)
had larger spatial and temporal variations in both C dynamic parameters (Pmax varying from 9.7–25.7 μmol m−2 s−1) and LAI (0.6–2.0). There were no clear relationships between dominant non-tussock vegetation types and a particular parameter
set. Our results suggest that C dynamics of the acidic tussock tundra slopes and hilltops in northern Alaska are relatively
simply described during the peak growing season. However, the foot-slopes and water tracks have more variable patterns of
LAI and C exchange, not simply related to the dominant vegetation type. 相似文献
999.
This commentary emphasizes the importance of including animal research and basic human research, contrasts the present state of affairs for biofeedback in the United States versus Europe, and proposes an alternative, more expanded definition of applied psychophysiology, which includes research, diagnostics, and education, as well as interventions. 相似文献
1000.