bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of large‐scale fragmentation on bryophytes in temperate forests
Authors: PHARO EMMA J. , LINDENMAYER DAVID B. , TAWS NICKI 
Published: September 2004

Summary

Bryophyte response to landscape fragmentation has not been investigated in replicated studies in temperate forests. Many bryophytes disperse widely but have narrow habitat requirements, suggesting that their responses to fragmentation may differ from other taxa.
We studied 16 sites in native eucalypt remnants located within an intensively managed plantation of exotic Pinus radiata. Eight further sites were dominated by exotic pines, and eight more were in large, continuous areas of native eucalypt forest located at the plantation boundary. We investigated how landscape context, remnant size and time since remnant isolation influence the bryophyte assemblage. Rocks, logs, soil, upturned trees and standing dead and live trees were sampled at each site.
Eucalypt remnants supported all but six of a total of 58 bryophyte taxa. Radiata pine sites were missing 40% of the species found in native forest, and pine was the only landscape context class not to have unique species. There was little difference in the richness or assemblage composition between the remnants and the unfragmented eucalypt forest.
Bryophyte assemblages differed between substrates but were similar across the same substrates even in different landscape context classes (except for rocks). Strip‐shaped remnants had more bryophytes in common with continuous forest than patch‐shaped remnants, while moss richness increased with remnant size.
Synthesis and applications. Native eucalypt remnants surrounded by intensively managed radiata pine plantation appeared to have retained, or regained, much of their bryoflora. Pine plantations were relatively depauperate, although burned eucalypt logs that remained after clearing native forest provided key substrates for many species and were crucial for maintaining bryophyte diversity. Forest managers aiming to retain bryophyte diversity should conserve native remnants of all sizes and retain suitable structural attributes, such as large decayed logs. Our findings support the hypothesis that many bryophytes have the mobility to overcome dispersal problems posed by fragmented landscapes if appropriate habitat or substrate is available.
Effects of nitrogen addition on the invasive grass Phragmites australis and a native competitor Spartina pectinata
Authors: RICKEY MARCIA A. , ANDERSON ROGER C. 
Published: September 2004

Summary

Phragmites australis is an invasive grass that has increased dramatically in distribution and abundance within the USA in the last 100 years. This study determined the effect of nitrogen addition on the growth of this invasive species compared with an indigenous competitor species, Spartina pectinata.
Twenty plants from each of three Illinois (USA) populations were collected and planted in the same garden in April 2001 and grown until August 2002. Following a year of growth in the garden, high‐nitrogen (45 g N m−2) and low‐nitrogen (5 g N m−2) treatments were applied to plants grown from paired rhizome cuttings from each plant. A single S. pectinata plant was grown with each P. australis. In August 2002, plants were harvested and above‐ and below‐ground biomasses were determined for both species.
Mean (± SE) P. australis above‐ and below‐ground biomasses were significantly higher in the high‐nitrogen treatment (68·4 ± 2·6 g and 39·0 ± 4·5 g, above‐ and below‐ground, respectively) than the low‐nitrogen treatment (37·3 ± 2·0 g and 25·5 ± 4·5 g). There were no differences in S. pectinata above‐ and below‐ground biomasses between high‐ (46·8 ± 3·2 g and 71·4 ± 9·6 g) and low‐ (45·4 ± 3·5 g and 50·3 ± 6·5 g) nitrogen treatments. The ratio of P. australis to S. pectinata biomass was used to compare the relative response of each species between nitrogen treatments; the mean ratio of P. australis to S. pectinata for the high‐nitrogen treatment (2·72 ± 0·499) was significantly higher than the low‐nitrogen treatment (1·83 ± 0·42).
Synthesis and applications. This study supports the hypothesis that P. australis benefits from increased nitrogen, and may be more likely to displace S. pectinata in nitrogen‐rich environments. Our study also confirms the importance of nitrogen in affecting the interactions between invasive and native plants. Control of P. australis may be aided by nutrient management.
Applicability of landscape and island biogeography theory to restoration of riparian understorey plants
Authors: HOLL KAREN D. , CRONE ELIZABETH E. 
Published: September 2004

Summary

Ecosystem recovery is influenced by processes at different spatial scales, yet land managers lack specific predictions on the relative importance of such processes that might guide management decisions. We tested whether ideas from landscape ecology (local vs. landscape scales) and island biogeography theory (patch size and isolation) predict restoration success for understorey plant communities in a highly fragmented riparian landscape, in an effort to provide guidance on how to allocate scarce restoration resources.
We sampled naturally colonizing riparian forest understorey plant communities in 15 riparian forests restored by planting native woody species along a 150‐km stretch of the Sacramento River in central California. We analysed native and exotic understorey species richness and cover as a function of biotic and abiotic local and landscape variables.
Cover and species richness of exotic understorey plants decreased strongly with increasing overstorey cover, and were lower in quadrats closer to river base flow.
Native understorey species richness and cover were negatively related to exotic cover and positively related to connectivity with remnant forest. Cover of native wind‐dispersed species was best explained by higher percentage forest cover surrounding a site within a 1000‐m buffer, whereas cover of native water‐dispersed species was higher closer to the river.
Neither patch size nor time since restoration explained a significant amount of native or exotic species richness or cover.
Synthesis and applications. Local factors explained more of the variance in understorey plant communities, but much of the variance remained unexplained. Our results provide weak support for the predictions of island biogeography theory and the importance of landscape‐scale variables. These theories did not have strong predictive power in this applied restoration context at this temporal scale. Given limited resources, efforts to restore understorey plant communities in this highly fragmented system should focus on local‐scale restoration methodologies, such as increasing cover of native overstorey species and reducing cover of exotic plants.
Effects of reindeer browsing on tundra willow and its associated insect herbivores
Authors: DEN HERDER MICHAEL , VIRTANEN RISTO , ROININEN HEIKKI 
Published: September 2004

Summary

Browsing by large mammals may strongly constrain the growth and reproduction of woody plants, and may alter the food quality and resource availability for herbivorous insects. The response of the plants may vary between different growth stages, and the preference of herbivores may be related to plant age. Understanding the effects of reindeer Rangifer tarandus browsing on the growth of woody forage plants is important in formulating guidelines for reindeer grazing management, especially in low productivity subarctic environments.
We studied the effects of summer browsing by reindeer on the growth and reproduction of willow Salix phylicifolia and on the abundance of its insect herbivores, by studying plants inside and outside exclosures over a period of 6 years.
The experiment was run in northern Finland and included 80 willow genets in an area near the timberline formed by mountain birch Betula pubescens. At the beginning of the experiment, half of the willows were cut at ground level to rejuvenate ramets.
Reindeer feeding was more intense on rejuvenated willow compared with old willow, and the effects of browsing were more pronounced on rejuvenated plants.
Reindeer browsing reduced the height of willow by c. 50%, shoot length by c. 30% and accelerated dieback of the shoots by c. 50%. Browsed willow produced fewer shoots, with fewer buds and floral catkins, than unbrowsed willow. Browsing also reduced the densities of the most common insect herbivores: leaf beetles of the genus Gonioctena (Coleoptera: Chrysomelidae) and gall‐inducing sawflies (Hymenoptera: Tenthredinidae) belonging to the genera Phyllocolpa, Eupontania and Euura.
Synthesis and applications. We show that reindeer browsing in summer reduces biomass and diminishes reproductive success of willow; it also lowers the numbers of its associated insect herbivores. Our results suggest that this effect will be most evident in low‐productivity tundra heaths where alternative forage plants, such as relatively palatable and productive graminoids, are scarce. We advise that reindeer should be maintained below the present levels of 2–3 reindeer km−2 to sustain the long‐term persistence of important forage plants such as willow in these low productivity habitats.
Single vs. multiple introduction in biological control: the roles of parasitoid efficiency, antagonism and niche overlap
Authors: PEDERSEN BRENT S. , MILLS NICHOLAS J. 
Published: September 2004

SummaryTheoretical studies have presented conflicting conclusions about the value of introducing multiple parasitoid species to control insect pests, depending on the presence and form of niche separation in the model. We investigated the impacts of multiple species introduction on control using a modelling approach.We started with a discrete‐time model of a pest, a primary parasitoid and a parasitoid that can interact antagonistically with the primary parasitoid as well as the pest. Implicit niche separation between parasitoids occurs via aggregated encounters with pests. We subsequently modified the simple model to include explicit niche separation and a refuge from parasitism, allowing the assumption of implicit niche separation to be relaxed. Multiple introduction is deemed beneficial if equilibrium pest densities are lower after the release of the interactive parasitoid.The outcome of biological control under the simple model depends largely on the search efficiency of the primary parasitoid. The primary parasitoid can co‐exist with an antagonistic interactive parasitoid, and multiple introduction is beneficial provided that the level of antagonism by the interactive parasitoid is not too high.In the more complex model with explicit niche separation, the ratio of primary search efficiencies of the two parasitoids, niche occupancy and degree of aggregation are shown to be important predictors of the outcome of multiple introduction. We demonstrate the importance of refuge breaking by an additional parasitoid as a compelling reason for multiple introduction. In addition, antagonistic interactions between parasitoids can be mediated by overall efficiency and explicit niche separation.For both implicit and explicit niche separation scenarios, the interactive parasitoid was excluded at high levels of niche overlap. Minimum pest densities with a three‐species equilibrium were similar between the two scenarios.Synthesis and applications. After consideration of explicit niche separation in a two parasitoid–one pest system, we conclude that multiple introduction is often a sound strategy in biological control, despite potential antagonistic interactions from competition, cleptoparasitism or facultative hyperparasitism. In selecting parasitoids for introduction, practitioners should evaluate the potential for niche separation between parasitoids and the overall efficiency of each parasitoid (primary search efficiency and aggregation of search) rather than dismiss a biological control candidate because of moderate antagonistic interactions.
Aetiology of obesity: a striving after wind?*
Authors: Rosmond R. 
Published: September 2004

SummaryThe current global epidemic of obesity is fuelled by a constant, unidirectional adverse effect on energy balance that exceeds the adaptive capacity of the system. The individual response to this environmental pressure is under the control of a variety of genes, which not only interacts with environmental factors but also with one another. Since the discovery that adipocytes may produce and secrete hormones, the adipose tissue has taken on increasing importance in the regulation of energy balance. Indeed, the pathogenesis of obesity, once regarded as so obvious and simple, is becoming one of the most complex in medical practice. From a clinical perspective, obesity is associated with a remarkably broad spectrum of health complications and, over the years, obesity‐related mortality has consistently increased. From a theoretical viewpoint, the growing complexity of factors affecting the liability to obesity, the inconsistency of scientific results, the lack of consensus among scientists, and so forth, obstruct our efforts to unravel the aetiology of obesity. Is the field of obesity research merely a striving after wind, and nothing more?
Evaluating commercial weight loss programmes: an evolution in outcomes research
Authors: Hamilton M. , Greenway F. 
Published: September 2004

SummaryThe increasing prevalence of obesity has been mirrored by a parallel increase in the number of commercial weight loss programmes. Research evaluating these programmes is meagre, however, compared to the numbers treated. Reluctance of commercial weight loss programmes to meaningfully evaluate their weight loss efficacy may arise from fear that competitors will use the results against them. Evaluation of commercial weight loss programmes usually progresses from testimonials, often by famous people who were successful, to uncontrolled studies of past participants evaluated either by the programme itself or by an outside entity. The gold standard, however, is a scientifically rigorous, controlled study of the programme conducted by an independent entity. Such a study, published in a peer‐reviewed journal, can gain credibility for a programme, as it did with Slim Fast, if the results are positive, or herald the end of the programme, as it was with Simeons human chorionic gonadotropin injection clinics. This review of the evolution of the evaluation process of commercial weight loss programmes leads us to conclude that consumers are likely to demand greater scientific rigour in the future, a change that will favour informed choice and discourage the practice of unrealistic advertising that raises false hopes.
Adipose tissue: new therapeutic targets from molecular and genetic studies – IASO Stock Conference 2003 report
Authors: Farmer S. R. , Auwerx J. 
Published: September 2004

SummaryThis review highlights the presentations and discussions held during the 2003 Stock Conference in Lisbon focussed on the identification of new therapeutic targets for the treatment of obesity and identified through molecular and genetic studies. Transcription factors and their cofactors, signalling pathways and new insights provided by cellular and genetic studies were discussed as potential new avenues to modulate adipocyte formation and function.
Firm Size Distribution in Small Samples
Authors: Buzzacchi Luigi , Valletti Tommaso M. 
Published: September 2004

AbstractSutton (1998) has recently proposed a theoretical lower bound to firm size inequality when a market is made of several independent submarkets. His results are valid asymptotically, as the number of submarkets becomes arbitrarily large. We show that, in small samples, his results can be interpreted as a positive relationship between an index of firm size inequality and the number of submarkets. We also test this relationship in the Italian motor insurance market.
Export Credit Guarantees, Moral Hazard and Exports Quality
Authors: García‐Alonso María del Carmen , Levine Paul , Morga Antonia 
Published: September 2004

AbstractWe analyse the role played by export credit guarantees (ECGs) in encouraging exports to developing countries. The existence of moral hazard on the side of the firm is introduced. We show that the inability of the exporter's government to verify the actual quality of the product will limit its ability to encourage trade through ECGs, once the coverage provided goes beyond a certain threshold. This result provides a rationale behind the limited coverage on ECGs.
Strategic Choice of the Price Structure and Entry Deterrence Under Price Cap Regulation
Authors: Iozzi Alberto , Fioramanti Marco 
Published: September 2004

AbstractThis paper shows that a price‐capped firm under the threat of entry in some of the markets it serves can strategically manipulate its price structure to deter entry. In doing so, the regulated firm uses the price cap constraint as a commitment device to an aggressive pricing behaviour in case of entry. A (dynamic) price cap generally entails that the prices allowed today are a function of the previous‐period prices and that the tighter is the constraint on each price, the larger is the quantity sold of this good in the previous period. Hence, the regulated firm may strategically choose its price structure before entry to place a tighter regulatory control on the prices set in the (potentially) competitive markets and to make it optimal to charge in these markets – in case of entry – prices so low that entry is unprofitable.
Output Variability and Economic Growth: the Japanese Case
Authors: Fountas Stilianos , Karanasos Menelaos , Mendoza Alfonso 
Published: September 2004

AbstractWe examine the empirical relationship between output variability and output growth using quarterly data for the 1961–2000 period for the Japanese economy. Using three different specifications of GARCH models, namely, Bollerslev's model, Taylor/Schwert's model, and Nelson's EGARCH model, we obtain two important results. First, we find robust evidence that the “in‐mean” coefficient is not statistically significant. This evidence is consistent with Speight's (1999) analysis of UK data and implies that output variability does not affect output growth. In other words, this finding supports several real business cycle theories of economic fluctuations. Second, we find no evidence of asymmetry between output variability and growth, a result consistent with Hamori (2000).
Agency Cost of Debt and Credit Market Imperfections: A Bargaining Approach
Authors: Koskela Erkki , Stenbacka Rune 
Published: September 2004

AbstractThis paper studies the effect of credit market imperfections, measured by the relative bargaining power of banks, on the agency costs of debt finance. The threshold of obtaining loan finance is shown to be independent of the relative bargaining power of the financier. However, lower relative bargaining power of banks leads to lower lending rates and investment return distributions with lower, but less risky returns. Thus, our analysis does not support the view, presented in a large existing literature, that there would be a trade‐off between reduced credit market imperfections and higher agency costs of debt finance.
Currency Options and Export‐Flexible Firms
Authors: Wong Kit Pong , Yick Ho Yin 
Published: September 2004

AbstractThis paper examines the production and hedging decisions of a globally competitive firm under exchange rate uncertainty. The firm is risk averse and possesses export flexibility in that it can distribute its output to either the domestic market or a foreign market after observing the realized spot exchange rate. To hedge against its exchange rate risk exposure, the firm can trade fairly priced currency call options of an arbitrary strike price. We show that both the separation and the full‐hedging results hold if the strike price of the currency call options is set equal to the ratio of the domestic and foreign selling prices. Otherwise, neither result holds. Specifically, we show that the optimal level of output is always less than that of an otherwise identical firm that is risk neutral. Furthermore, an under‐hedge (over‐hedge) is optimal whenever the strike price of the currency call options is below (above) the ratio of the domestic and foreign selling prices.
The Wretchedness of Belief
Authors: Plant Bob 
Published: September 2004

ABSTRACTIn Culture and Value Wittgenstein remarks that the truly “religious man” thinks himself to be, not merely “imperfect” or “ill,” but wholly “wretched.” While such sentiments are of obvious biographical interest, in this paper I show why they are also worthy of serious philosophical attention. Although the influence of Wittgenstein's thinking on the philosophy of religion is often judged negatively (as, for example, leading to quietist and/or fideist‐relativist conclusions) I argue that the distinctly ethical conception of religion (specifically Christianity) that Wittgenstein presents should lead us to a quite different assessment. In particular, his preoccupation with the categorical nature of religion suggests a conception of “genuine” religious belief which disrupts both the economics of eschatological‐salvationist hope, and the traditional ethical precept that “ought implies can.” In short, what Wittgenstein presents is a sketch of a religion without recompense.
Schleiermacher and the Ethics of Authenticity
Authors: Sockness Brent W. 
Published: September 2004

ABSTRACTSchleiermacher's Soliloquies not only represent a pivotal work in this classically modern theologian's development as a moral philosopher. They are also arguably the principal moral writing of the early German romantic movement and therefore a significant, if widely overlooked, contribution to the history of ethics in the West. This essay provides a comprehensive interpretation and modest retrieval of this unusual and difficult work by bringing Schleiermacher's early “ethics of individuality” into conversation with Charles Taylor's conception of “expressivist” understandings of human selfhood. It argues that the Monologen are a signal instance of what Taylor has subtly characterized as romanticism's expressivist impulse.
Feminism and Postmodernism in Susan Frank Parsons
Authors: Gudorf Christine E. 
Published: September 2004

ABSTRACTReviewing The Ethics of Gender, Feminism and Christian Ethics, and The Cambridge Companion to Feminist Theology, the author suggests that Susan Parsons responds to questions postmodernism has posed to both feminism and Christian ethics by using insights gained from various accounts of the moral subject found in feminist philosophy, ethics, and theology. Hesitant to embrace postmodernism's critique of the possibility of ethics, Parsons redefines ethics by establishing a moral point of view within discursive communities. Yet in her brief treatment of Emmanuel Levinas, Parsons does not explore the postmodern option he offers feminists: an understanding of moral responsibility that can be critical of ethics. Parsons also ignores some feminist perspectives in the physical and natural sciences, thereby missing valuable insights of feminists who insist upon the materiality of the body.
‘Ein Deutsches Trauma?’: Zur Schamlosigkeit Deutscher Opferidentifikation
Authors: Frahm Ole 
Published: September 2004

AbstractDer Artikel kritisiert anhand von Habbo Knochs Dissertation Die Tat als Bild und Aleida Assmanns Essay Ein deutsches Trauma eine Tendenz in der bundesdeutschen Wissenschaft, die Traumatisierung aufgrund der Vernichtung der europäischen Juden mit einer Traumatisierung der Deutschen durch Bilder von der Befreiung der Konzentrationslager gleichzusetzen. Die Kontinuität deutscher Opferidentifikation ist in diesem Diskurs völlig vergessen und so fortgeschrieben. In einem ersten Teil wird deshalb anhand von populären Bildern Erich Ohsers und A. Paul Webers von 1942/43 die Kontinuität der Darstellung der Deutschen als Opfer nachgezeichnet, die sich in Schreckensbildern mit Leichenbergen materialisiert. Im zweiten Teil wird ein Begriff der Scham entwickelt, der an Primo Levis ‘Scham, ein Mensch zu sein’ anschließt. Dieser kritisiert Aleida Assmans Begriff einer deutschen Scham aufgrund eines Traumas durch die Betrachtung von Schreckensbildern.