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1.
Avian productivity in urban landscapes: a review and meta-analysis   总被引:1,自引:0,他引:1  
There is an urgent need to thoroughly review and comprehend the effects of urbanization on wildlife in order to understand both the ecological implications of increasing urbanization and how to mitigate its threat to biodiversity globally. We examined patterns in comparative productivity of urban and non-urban passerine birds, using published estimates from paired comparisons, and by reviewing and developing explanations in terms of resources, competitors, predators and other specifically urban environmental factors. The most consistent patterns were for earlier lay dates, lower clutch size, lower nestling weight and lower productivity per nesting attempt in urban landscapes; these were supported by a formal meta-analysis. Nest failure rates did not show consistent patterns across the species considered. We suggest that food availability is a key driver of differences in passerine demography between landscapes. In urban habitats, human-provided food may improve adult condition over winter, leading to earlier lay dates and, in some species, to higher survival and higher breeding densities, but paucity of natural food may lead to lower productivity per nesting attempt. We demonstrate that additional comparative research is needed on a wider range of species, on the effects of natural and human-provided food availability, and on the differences in survival and dispersal between urban and non-urban populations. Importantly, better-targeted research and monitoring is needed in areas that are at greatest threat from urbanization, especially in the developing world.  相似文献   

2.
Although several studies have examined the functional diversity of freshwater macroinvertebrates, the variety of methodologies combined with the absence of a synthetic review make our understanding of this field incomplete. Therefore, we reviewed the current methodology for assessing functional diversity in freshwater macroinvertebrate research. Our review showed that most papers quantified functional diversity using biological traits, among which feeding habits were the most common traits probably due to the assumed links between feeding and ecosystem functions. A large number of diversity measures have been applied for quantifying functional diversity of freshwater macroinvertebrate assemblages, among which Rao’s quadratic entropy looks like the most frequent. In most papers, functional diversity was positively related to taxon richness, and functional redundancy was a key concept in explaining this correlation. Most studies detected strong influence of the environmental factors as well as human impact on functional diversity. Finally, our review revealed that functional diversity research is biased towards European running waters and is hindered by yet insufficient information on the autecology of macroinvertebrates.  相似文献   

3.
Grasslands are the dominant landscape in China, accounting for 40% of the national land area. Research concerning China's grassland ecosystems can be chronologically summarized into four periods: (i) pre-1950s, preliminary research and survey of grassland vegetation and plant species by Russians, Japanese and Western Europeans, (ii) 1950-1975, exploration and survey of vegetation, soils and topography as part of natural resource inventory programmes by regional and national institutions mainly led by the Chinese Academy of Sciences, (iii) 1976-1995, establishment of field stations for long-term ecological monitoring and studies of ecosystem processes, (iv) 1996-present, comprehensive studies of community dynamics and ecosystem function integrating multi-scale and multidisciplinary approaches and experimental manipulations.Major findings of scientific significance in China's grassland ecosystem research include: (i) improved knowledge on succession and biogeochemistry of the semi-arid and temperate grassland ecosystems, (ii) elucidation of life-history strategies and diapause characteristics of the native grasshopper species as one of the key grassland pests, and (iii) development of effective management strategies for controlling rodent pests in grassland ecosystems. Opportunities exist for using the natural grasslands in northern China as a model system to test ecosystem theories that so far have proven a challenge to ecologists worldwide.  相似文献   

4.
The effect of water-level (WL) fluctuations on both the structure and functioning of coastal marshes is well documented, and in the past, scientists have demonstrated this by relating historical changes in the areal cover of emergent vegetation (EM) of a particular site to corresponding WL data. This approach of relating areal cover to WL cannot be applied to multiple sites from a region experiencing the same WL because in that instance, WL would be a constant and cannot be used as an explanatory variable for emergent cover. In a previous study of Cootes Paradise Marsh, we proposed the use of a Digital Elevation Model (DEM) to examine the effect of WL fluctuations on emergent plant cover over a 60-year period (1934–1993), and found that the inundated area (IA) was a better predictor of emergent cover than WL. However, the transferability of the marsh-inundation model and the related uncertainty has not yet been tested in a distinct geographic region. In the present article, we test the transferability of the model and develop a regional model of vegetation response to validate the DEM-based method. We confirm the existence of a highly significant relationship between percent IA and percent emergent cover over a large spatial scale in Eastern Lake Ontario. Additionally, we showed that this general relationship might be modified by the degree of urbanization in wetland watersheds. Our results suggest that this DEM-based approach is useful for predicting the aggregate response of EM to annual WL fluctuations and is transferable from local to regional scales. Handling editor: L. M. Bini  相似文献   

5.
We contrast some recent uses of the concept of male-female conflict, with the type of conflict that is inherent in traditional Darwinian female choice. Females in apparent conflict situations with males may suffer reduced lifetime reproduction, but nevertheless benefit because they obtain sons with superior manipulative abilities. Female defences against male manipulations may not be 'imperfect' because of inability to keep pace with male evolution, but in order to screen males and favour those that are especially good manipulators. We examine the consequences of these ideas, and of the difficulties of obtaining biologically realistic measures of female costs, for some recent theoretical and empirical presentations of male-female conflict ideas, and find that male-female conflict in the new sense is less certain than has been commonly supposed. Disentangling previous sexual selection ideas and the new conflict of interest models will probably often be difficult, because the two types of payoffs are not mutually exclusive.  相似文献   

6.
Hyperhidrosis: a review of current management   总被引:11,自引:0,他引:11  
Primary hyperhidrosis is a troublesome disorder of excessive perspiration that affects as much as 1 percent of the population. Sufferers are usually young and are often affected by related social, professional, and psychological problems. Many methods for treating hyperhidrosis exist; however, no single treatment is without its weakness or complications. This article aims to clarify the issues related to the use of each treatment modality, including the most recently proposed method using botulinum toxin.  相似文献   

7.
This historical review was compiled and edited by Giorgio Forti, whereas the other authors of the different sections are listed alphabetically after his name, below the title of the paper; they are also listed in the individual sections. This review deals with the research on photosynthesis performed in several Italian laboratories during the last 50 years; it includes research done, in collaboration, at several international laboratories, particularly USA, UK, Switzerland, Hungary, Germany, France, Finland, Denmark, and Austria. Wherever pertinent, references are provided, especially to other historical papers in Govindjee et al. [Govindjee, Beatty JT, Gest H, Allen JF (eds) (2005) Discoveries in Photosynthesis. Springer, Dordrecht]. This paper covers the physical and chemical events starting with the absorption of a quantum of light by a pigment molecule to the conversion of the radiation energy into the stable chemical forms of the reducing power and of ATP. It describes the work done on the structure, function and regulation of the photosynthetic apparatus in higher plants, unicellular algae and␣in photosynthetic bacteria. Phenomena such as photoinhibition and the protection from it are also included. Research in biophysics of photosynthesis in Padova (Italy) is discussed by G.M. Giacometti and G.␣Giacometti (2006).  相似文献   

8.
It is the best of times for biofilm research. Systems biology approaches are providing new insights into the genetic regulation of microbial functions, and sophisticated modelling techniques are enabling the prediction of microbial community structures. Yet it is also clear that there is a need for ecological theory to contribute to our understanding of biofilms. Here, we suggest a concept for biofilm research that is spatially explicit and solidly rooted in ecological theory, which might serve as a universal approach to the study of the numerous facets of biofilms.  相似文献   

9.
  1. Semi-arid and arid landscapes (dry-lands) cover 41% of the Earth’s land surface over five continents. These areas are home to 55% of mammal species. Bats have the second highest species richness among mammals, and, although many species are adapted to arid conditions, they are particularly sensitive in these habitats and require conservation priority.
  2. Information on bats in arid and semi-arid landscapes is scattered, patchy and focused on small-scale studies; therefore, we undertook a systematic review using the PRISMA protocol to identify the current knowledge status, detect knowledge gaps and propose future research priorities.
  3. We analysed 346 published articles and evaluated 40 topics within five topic categories (taxa studied, methodologies used, biology, ecology and conservation). The most commonly studied topic categories were ecology and biology. However, we found a gap in the topic category conservation (including topics such as conservation status and roost conservation). Our network analysis of topics within the categories showed that most ecology papers were focused on distribution, species richness and habitat use.
  4. When we analysed keywords, we found that phylogeny, taxonomy and distribution demonstrated relatively high presence. Moreover, comparison of the percentage of studies conducted in dry-lands and the percentage of land surface area covered by dry-lands in the continents revealed that dry-lands in Africa and Australia were especially under-represented. Our review shows that knowledge of bats in semi-arid and arid landscapes is biased towards new records of the distribution of species, as well as covering systematic/taxonomic and morphological aspects of bat biology.
  5. We suggest that research on conservation measures and guidelines to protect the bat species found in semi-arid and arid landscapes should be prioritised, together with the sharing of knowledge with local practitioners and the development of citizen science programmes.
  相似文献   

10.
Mapping the demand for ecosystem services (ES) has received increased attention in scientific research and is seen as a relevant tool to inform conservation planning, land use planning and management. Yet, there is a varying understanding of the concept of ES demand, which has implications on how and where ES demand is being mapped. In this paper we review the current conceptual understanding of ES demand, indicators to measure demand and the approaches used to quantify and map demand. We identified four distinct “demand types”, which relate to different ecosystem service categories. These demand types include demand expressed in terms of (1) risk reduction, (2) preferences and values, (3) direct use or (4) consumption of goods and services. Each of the demand types was linked to specific methods applied in the reviewed literature. We found that operationalization of ES demand in policy, planning and management requires a more consistent understanding and definition of ES demand, its drivers and its temporal dynamics. Furthermore, the impact of demands for multiple ecosystem services on land use change needs to be investigated. This will allow for the consideration of temporal and cross-level interactions between supply and demand of ecosystem services and its impacts in land use change modelling.  相似文献   

11.
12.

Purpose

Much collective wisdom and experience have been gained as an increasing number of Life Cycle Assessment (LCA) reviews are conducted. However, specifics on how and when to conduct critical review of LCA studies are still lacking. Toward this need, a technical session entitled “LCA Critical Review” was held during the Life Cycle Management (LCM) conference in Gothenburg, Sweden, 26 August 2013. The goal of the session was to have experts address LCA critical review as well as engage attendees in discussing gaps in the current guidance and how the review process can be improved.

Methods

The LCM session consisted of six presentations followed by open discussion with all session attendees. This paper begins with a review of the current state-of-the-practice in LCA critical review (CR) followed by a summary of the LCM session. It concludes with suggestions for how the newly drafted technical specification, ISO TS 14071 Critical review processes and reviewer competencies, can be improved as it is being developed.

Results and discussion

ISO TS 14071 promises to provide additional guidance to move the practice forward. But at only eight pages in length, its potential effectiveness appears moderate. Additional detailed guidance is needed to move the critical review process toward increased uniformity and clarity of practice, for example, when critical review is necessary.

Conclusions

A session on LCA critical review is planned to be held during the Life Cycle Management 2015 conference which will occur in Bordeaux, France (http://lcm2015.org/). Discussion on these issues related to LCA review will be continued.  相似文献   

13.
14.
Körner M  Reubi JC 《Peptides》2007,28(2):419-425
Many peptide hormone receptors are over-expressed in human cancer, permitting an in vivo targeting of tumors for diagnostic and therapeutic purposes. NPY receptors are novel and promising candidates in this field. Using in vitro receptor autoradiography, Y1 and Y2 receptors have been found to be expressed in breast carcinomas, adrenal gland and related tumors, renal cell carcinomas, and ovarian cancers in both tumor cells and tumor-associated blood vessels. Pathophysiologically, tumoral NPY receptors may be activated by endogenous NPY released from intratumoral nerve fibers or tumor cells themselves, and mediate NPY effects on tumor cell proliferation and tumoral blood supply. Clinically, tumoral NPY receptors may be targeted with NPY analogs coupled with adequate radionuclides or cytotoxic agents for a scintigraphic tumor imaging and/or tumor therapy.  相似文献   

15.
We reviewed the use of captive European starlings (Sturnus vulgaris) in scientific research published between 2000 and 2004. We estimated the numbers of birds used and documented their origin and the range of husbandry regimes employed with the aim of comparing current practice with the new European guidelines for husbandry of laboratory animals. Over the five-year period, 106 primary articles report the use of an estimated total of 2490 captive starlings. The majority of birds were caught from the wild either as adults or fledglings, and only 3% were hand-reared from chicks. There was considerable variation in husbandry. In the majority of cases, standards fell below those currently recommended as best practice in the UK and cited in new European guidelines. The median volume of home cages employed was 0.42 m3 (0.13-5.1 m3, interquartile range), whereas current recommendations suggest a minimum of 1.0 m3 for a singly-housed bird. The median volume of space allowed per bird was 0.13 m3/bird (0.08-1.05 m3/bird, Q1-Q3), whereas current recommendations suggest a minimum of 0.33 m3/bird. Only 27% of the articles mentioned providing any form of environmental enrichment for birds in their home cages. We recommend that more research be conducted into the welfare of starlings to inform legislation and guidelines, and thus maximize the welfare of captive animals.  相似文献   

16.
Palaeoecological reconstructions based on a single proxy are limited, but by combining pollen, biogeochemistry and grass cuticle analysis, ecosystem structure and function can be better understood. Lake Rutundu is a small, subalpine lake on the northeast flank of Mt Kenya. During the last glacial, pollen evidence suggests a shrub grassland dominated by Afroalpine taxa and Poaceae, representing a dry, cold, open environment. The δ13C values of terrestrial biomarkers imply a high proportion of C4 plants. Grass cuticle analysis allows resolution of the different C4 subtypes and shows that the vegetation was dominated by tall C4 panicoid grasses, prone to frequent fires. During the Holocene, Poaceae pollen declined while subalpine shrubs increased. The δ13C values of terrestrial biomarkers imply a C3-dominated vegetation. Together with an expansion of rainforest at lower altitudes, this suggests wetter conditions more favourable to C3 plants. Increased percentages of C3 pooid grass cuticles confirm a reduction in moisture stress.  相似文献   

17.
LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Describe the differential diagnosis of xanthelasma palpebrarum. 2. Discuss the various nonsurgical and surgical treatment options and their advantages and disadvantages. 3. Describe the circumstances in which recurrence is most likely after treatment. Xanthelasma palpebrarum is the most common cutaneous xanthoma. It typically presents in middle-aged and older adults, most often around the eyelids. The diagnosis can often be made on clinical grounds alone. For the plastic surgeon, it is important to apply an algorithmic approach to the treatment of these lesions. Depending on the size and location, several different methods can be used to address this problem, ranging from simple excision, to laser treatment, to chemical peeling. This article addresses the underlying pathophysiology of xanthelasma and the currently accepted modes of treatment.  相似文献   

18.
19.
The aim of the study reported here was to provide some basic and general information on the suitability of an experimental sheep model for conducting in vivo orthopedic studies. The authors have classified the fundamental aspects that should be carefully evaluated when using sheep as an experimental model in orthopedic research: factors strictly related to bone anatomy and formation; and factors strictly affecting bone physiology, such as gastrointestinal mineral and vitamin absorption, and reproductive cycle. Future investigations should address all of the aspects highlighted, since there is no animal with the same anatomic, biochemical, physiologic, and biological characteristics as those of human beings. Moreover, useful data for treating orthopedic patients are based not only on good planning and study design, but also on perfect knowledge of the animal used and the differences between the model and the human being. The authors hope that this report will contribute to extrapolation of reliable data for use of sheep in the orthopedics field.  相似文献   

20.
兰科菌根的生态学研究进展   总被引:2,自引:0,他引:2  
兰科植物(Orchidaceae)是典型的菌根植物,自然条件下其种子的成功萌发和生长的早期阶段对菌根真菌有绝对的依赖性,在有些成年兰科植物中菌根真菌仍起着重要的作用。目前大部分兰科植物已为濒危物种,鉴于兰科植物天然的菌根共生关系,开展兰科植物和菌根真菌互作的生态学研究不仅具有极高的科研价值,更有助于兰科植物的物种保护和野生种群的生态恢复。近年研究表明,兰科植物对真菌的选择和二者共生关系的建立与菌根真菌的空间分布和丰度密切相关,然而当前对自然环境中兰科菌根真菌的实际分布还了解甚少,因此文章从生态学角度系统分析兰科植物与菌根真菌的关系,探讨该领域的研究热点,旨在为兰科菌根的生态学研究提供参考。  相似文献   

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