bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of patch characteristics on browsing of tree seedlings by mammalian herbivores
Authors: Pietrzykowski E. , McArthur C. , Fitzgerald H. , Goodwin A. N. 
Published: June 2003

Summary

In south‐eastern Australia, browsing of commercial tree seedlings by mammalian herbivores in plantation forestry incurs a large economic cost to the industry, through its effect on tree survival, growth and form. In the absence of lethal methods to control herbivore populations, appropriate manipulation of vegetation through silvicultural management may reduce browsing but it relies on understanding the feeding responses of the herbivores to such changes.
We evaluated the extent to which vegetation patch characteristics affected browsing of pine Pinus radiata seedlings by generalist mammalian herbivores, including red‐bellied pademelons Thylogale billardierii, Bennett's wallaby Macropus rufogriseus rufogriseus and the common brushtail possum Trichosurus vulpecula.
In field trials, browsing of pine seedlings was greatest when they were located in patches of high quality, i.e. palatable short vegetation (grass), intermediate in high‐quality tall vegetation (Lomandra longifolia) and least in low‐quality tall vegetation (bracken and shrub). Patch structure also affected browsing: in low‐quality patches pine seedlings were browsed more in short vegetation patches (12–24 cm shorter than the seedling) than in tall vegetation patches (at least as tall as the seedling). This difference was at least partly because herbivores took, on average, 2 weeks longer to locate seedlings in tall than in short vegetation.
In trials with captive red‐bellied pademelons and brushtail possums, pine seedlings were browsed similarly in small short grass and soil patches. However, when these patches were large and spatially separated, they were browsed more in short grass than soil patches. Selection at the patch or individual plant level therefore depended on spatial scale and proximity of the patches.
Synthesis and applications. The influence of patch characteristics on browsing has the potential to be exploited for the management of browsing damage to commercially important tree seedlings in forestry plantations. Retention of relatively tall vegetation, particularly if it is unpalatable, in areas at risk of heavy browsing, for example by delaying the use of herbicide, may be a useful management strategy for reducing browsing. This needs to be weighed against the potential detrimental competitive effects of neighbouring vegetation on the seedlings.
Application of merged 1‐m and 4‐m resolution satellite data to research and management in tropical forests
Authors: Read Jane M. , Clark David B. , Venticinque Eduardo M. , Moreira Marcelo P. 
Published: June 2003

Summary

Until very recently there have been no digital data from satellites for studying events that occur at scales of 10–1000 m2 over large areas (100–100 000 ha). Many phenomena of interest to ecologists, such as impacts of selective logging on forest processes, occur over large extents but at local scales. Here we report results from a pilot project to evaluate through visual interpretation the potential of newly available 1‐m panchromatic and 4‐m multi‐spectral data from the IKONOS satellite, for studying forest structure, dynamics and logging impacts in logged and old‐growth tropical moist forest.
The study area, the Mil Madeireira Itacoatiara Ltda site of Precious Woods Amazon, near Itacoatiara, Amazonas, Brazil, is managed using reduced‐impact logging practices to minimize environmental impacts, and thus represents a lower bound for logging impacts in tropical rain forests.
The IKONOS image was georeferenced using uncorrected global positioning system (GPS) locations for 10 control trees whose crowns were clearly visible in the image. The root mean square error (RMSE) of the geometric transformation was 4 m, while the mean crown diameter of 50 randomly chosen trees in old‐growth forest was 9·4 m. The fact that the RMSE was less than half the average crown diameter implies that it will usually be possible to locate from the ground crowns that are distinct on the image, given sufficiently accurate GPS locations.
IKONOS data are well suited for evaluating and monitoring logging impacts. Many impacts of logging were clearly observable in the image, including major and some minor roads, logging patios and larger logging gaps. Smaller extraction roads and logging gaps were not observable.
Many individual trees were distinct on the IKONOS image, indicating that it is now feasible to conduct demographic studies of tropical rain forest canopy trees based on repeated satellite observations. Linking these remotely sensed data to ground data will require improved GPS positions, because it is currently difficult to obtain accurate GPS readings in tropical rain forest understoreys.
Synthesis and applications. IKONOS 1‐m and 4‐m data were found to be useful for identifying individual trees as well as some logging management features in a tropical moist forest in central Amazonia. These data will have many applications for research and management of intervened and old‐growth tropical forests, including planning and assessment of logging activities, as well as monitoring adherence to certification criteria such as those of the Forest Stewardship Council. Rapid development of these applications will come from building on existing data on forest structure and function, and by fostering collaborations between remote sensing scientists, ecologists and natural resource managers.
The relative roles of domestication, rearing environment, prior residence and body size in deciding territorial contests between hatchery and wild juvenile salmon
Authors: Metcalfe Neil B. , Valdimarsson Sveinn K. , Morgan Ian J. 
Published: June 2003

SummaryInteractions between captive‐reared and wild salmonids are frequent because hatcheries annually rear millions of fish for release in conservation programmes while many thousands of domesticated fish escape from fish farms. However, the outcome of competition between captive‐reared and wild fish is not clear: wild fish may be smaller and less aggressive than hatchery fish, but they have more local experience and a prior residence advantage. Moreover, it is important to know whether any competitive differences are genetic (due to the process of domestication) or due to the rearing environment.We therefore examined the factors influencing competition for feeding territories in juvenile Atlantic salmon. We studied the effect of domestication by using three independent stocks of both domesticated and wild‐origin fish, all of which were reared in a common hatchery environment. We also used fish from the same wild stocks that had been living in the wild. Territorial contests were staged in stream tank compartments between pairs of fish differing in origin or rearing environment; the relative importance of body size and prior residence was also assessed.All three stocks of domesticated fish were generally dominant over wild‐origin fish when both had been raised in a common hatchery environment. If the wild‐origin fish were given a 2‐day period of prior residence on the territory this asymmetry in dominance was reversed. However, domesticated fish did not gain any additional advantage from being prior residents. The relative body size of the two contestants had a negligible effect on contest outcomes.Truly wild fish (i.e. those of wild origin that had also grown up in the wild) were generally dominant over domesticated or wild‐origin fish that had been hatchery‐reared. Differences in body size between contestants had no effect on the outcome.Synthesis and applications. These results show that, while juvenile farmed Atlantic salmon are inherently more aggressive than wild‐origin fish, the hatchery environment reduces their ability to compete for territories with wild resident fish. Rearing salmon in conventional hatcheries for later release into the wild where natural populations already exist may not be a prudent conservation measure; it is preferable to plant eggs or first‐feeding fry rather than attempt to ‘help’ the fish by rearing them through the early life stages.
Demography and management of the invasive plant species Hypericum perforatum. II. Construction and use of an individual‐based model to predict population dynamics and the effects of management strategies
Authors: Buckley Yvonne M. , Briese David T. , Rees Mark 
Published: June 2003

Summary

Hypericum perforatum, St John's wort, is an invasive weed of natural and agro‐ecosystems in south‐eastern Australia. In previous work we used a long‐term data set to determine which plant traits and environmental factors influence population growth and persistence in this species. These results were then used to parameterize an individual‐based model of the population dynamics of H. perforatum, and this model was used to make predictions about what control strategies will be most effective for populations in open and shaded sites.
The model was constructed using multi‐level, mixed‐effects statistical models of growth, survival, fecundity and damage, incorporating intrinsic plant variables, environmental variables, herbivory and spatial and temporal stochasticity.
We found that populations in shaded and open sites had different dynamics and responses to control strategies. Shaded populations took longer to reach infestation densities and were less affected by herbivory and reductions in survival than open populations. Open populations increased faster in response to increases in rainfall, but this was not so for shaded populations.
We used sensitivity testing and management simulations to predict that the most successful control strategies will involve a reduction in vegetative size in both open and shaded sites. Reductions in flowering stem size and survival in shaded and open sites, respectively, are predicted to be the next most successful strategies. Dry conditions in the austral autumn/winter adversely affect populations in both open and shaded sites.
Synthesis and applications. These models have enabled us to rank management strategies based on quantitative analysis of their potential effects on population size. This is an important tool not only for ecologists concerned with control of invasive species but for conservation biologists trying to understand the factors limiting a rare or endangered species.
The relative importance of cattle grazing in subtropical grasslands: does it reduce or enhance plant biodiversity?
Authors: Mcintyre S. , Heard K. M. , Martin T. G. 
Published: June 2003

Summary

Livestock grazing enterprises have potentially threatening effects on the conservation of plants in grassy subtropical eucalypt woodlands. Commercial levels of grazing could cause local extinctions of sensitive native species and/or reductions in abundance and species richness in native pastures.
We studied the nature of grazing impacts on the diversity and composition of herbaceous plants and used a natural experiment to analyse the effects of disturbances (cattle grazing, soil disturbance, water enrichment) and environment (lithology, slope position, presence of trees) on plant community composition in eastern Australia. We sampled pastures and reserves at 191 sites over an area of 3000 ha.
Canonical correspondence analysis (CCA) was used to explore the relative importance of disturbance and environment in accounting for floristic variation and to examine individual species responses. From individual responses, we identified seven response groups relating to grazing. The factors analysed explained small but significant amounts of floristic variation, and there were interactions between soil disturbance, water enrichment and grazing.
We explored the hypothesis that grazing increased species density at small scales but decreased it at landscape scales, due to the elimination of grazing‐sensitive species. Our data did not support the hypothesis, as there were similar numbers of species that increase with grazing (increasers) and species that decline with increasing grazing (decreasers) in the assemblage. However, there were more native decreasers and more exotic increasers in the assemblage.
Synthesis and applications. For land managers to retain plant diversity on grazed landscapes, it would be desirable to provide all levels of grazing pressure across the landscape, including areas protected from livestock grazing. This would apply to all plant communities where both grazing increasers and decreasers are present. Extensive areas supporting grassland with a tall tussock structure that is selectively grazed are most important, as all plant response groups have some representation and ecosystem function is retained under moderate grazing. In terms of regional conservation planning, the protection and enlargement of areas protected from livestock grazing is important in the study area, as these occur on only about 4% of the landscape and are threatened by on‐going disturbances and land‐use intensification.
The impact of stroke practice guidelines on knowledge and practice patterns of acute care health professionals
Authors: Heinemann Allen W. , Roth Elliot J. , Rychlik Karen , Pe Klaren , King Caroline , Clumpner Jennifer 
Published: June 2003

AbstractRationale, aims and objectives  The Agency for Healthcare Research and Quality's Post‐Stroke Rehabilitation Guidelines were developed to improve the quality, appropriateness and effectiveness of rehabilitation practices. An important goal of the guidelines process is to disseminate information to practitioners in order to encourage adoption of effective practices. To date, no systematic evaluation of these guidelines has been completed, nor has a programme been designed to evaluate the effectiveness of an educational programme about the guidelines. The objective was to evaluate changes in knowledge and practice following presentation of a lecture‐based, educational programme about post‐stroke rehabilitation guidelines.Methods  The research design was a single group, pre‐test–post‐test design without a comparison group. A knowledge and referral practices questionnaire was developed specifically for this study.Results  Lecture attendance was not associated with an increase in knowledge or referrals. However, we found that respondents who made more referrals at follow‐up had a higher knowledge level at pre‐test. Also, those who completed a follow‐up assessment knew more about the guidelines at the initial assessment than did those who did not complete the follow‐up assessment. In addition, doctors knew more about stroke rehabilitation than the non‐doctors, both at the pre‐test and follow‐up.Discussion and conclusions  Encouraging behaviour change among doctors and allied health professionals in referrals and clinical practice is a complicated process. Providing individual follow‐up and lengthier contacts, assuring that care providers receive high‐quality evidence that guidelines improve care, and consulting with key decision‐makers about guideline implementation might enhance behaviour change.
Generalizability: beyond plausibility and handwaving
Authors: Shahar MD MPH Eyal 
Published: June 2003

AbstractThe question of how we apply knowledge from biomedical science to medical and public health practice has been the subject of heated debates about generalizability and related concepts, such as applicability and inductive inference. In this essay, I interpret the term from the perspective of two causal models: determinism and indeterminism. I suggest that theories of generalizability can be formulated on the basis of both models and take the form of testable but unverifiable hypotheses, an attribute that is common to all scientific theories. Nonetheless, there is one noteworthy difference between the two models: determinism allows one to rationalize a decision to treat a certain kind of patient but only indirectly a decision to treat any particular patient, whereas indeterminism accommodates both types of decisions.
The state of the science and art of practice guidelines development, dissemination and evaluation in Canada
Authors: Graham Ian D. , Beardall Susan , Carter Anne O. , Tetroe Jacqueline , Davies Barbara 
Published: June 2003

AbstractThe Canadian Medical Association (CMA) maintains a database of clinical practice guidelines (CPGs) developed or endorsed by Canadian organizations. The study purpose was to describe how these guidelines were developed, disseminated and evaluated. A survey was mailed to the developer of each CPG registered in the CMA Infobase between June 1996 and December 1999. Data were received for 730 unique guidelines (response rate of 70%) developed by 75 organizations. Of these, 72% were developed by committees that had a formal process for selecting their members. The scientific literature was reviewed for all of the guidelines, a computerized search undertaken for 88% and the search strategy included 34% of CPG documents. An attempt was made to grade the quality of the evidence underpinning 54% of the guidelines. For most guidelines, consensus about values or judgements was reached by expert opinion through open discussion (78% of guidelines). The most common strategies used to disseminate the guidelines were direct mailing of guidelines to members of the developing organization (80% of all guidelines), publishing guidelines in newsletters/journals (76%), direct mailing to others (73%), electronic dissemination (62%), educational or continuing medical education activities (50%), and providing information about guidelines to patients/consumers (47%). Overall, 5% of the guidelines have been evaluated to determine their impact on health outcomes. During the 5‐year study period (1994–99), the more recent guidelines were more likely to use multidisciplinary development panels, report the literature search strategies and grade the quality of the evidence. The CPG development process in Canada is becoming more rigorous and reproducible, but there is still considerable room for improvement. In addition to encouraging Canadian guideline developers to use more rigorous and transparent methods, considerably more attention must be focused on using and identifying effective and cost‐effective strategies to promote and facilitate the uptake of guidelines by practitioners and to evaluate the impact of guidelines on patient outcomes.
The Australian Centre For Evidence‐based Clinical Practice Generic Audit Tool: Auditmaker for health professionals
Authors: Shakib Sepehr , Phillips Paddy A 
Published: June 2003

AbstractAudit is an important step in the process of health care evaluation and quality improvement. Some of the barriers to audit include the lack of support in initiating an audit, difficulty with data collection and lack of time. Auditmaker is a computer package that guides the clinician through the initial process of designing an audit, choosing factors and outcomes to analyse, then provides customizable data entry forms, and finally simple reports summarizing the data. It has user‐friendly features, such as help buttons, drop‐down lists and built in comorbidities and outcomes of common interest. It provides a generic tool for performing an audit as well as providing an opportunity for different clinicians in different institutions or practice settings to perform similar audits using the same data collection tool, which can provide the basis of benchmarking. Auditmaker is available for downloading from the ACEPCP website: http:www.acebcp.org.au.
Evidence‐based practice in mental health: practical weaknesses meet political strengths
Authors: Tanenbaum Sandra 
Published: June 2003

AbstractRationale, aims, and objectives  Evidence‐based medicine (EBM) has given rise to evidence‐based practice (EBP) in the field of mental health. EBP too is predicated on an evidence hierarchy and has the goal of using the “best evidence” (usually randomized controlled trials) to improve practice. EBP is increasingly influential in mental health care in the U.S. Growing numbers of researchers and public officials endorse its claims and pursue its benefits. The rationale for this paper is to examine the potential of EBP for the field of mental health—and public mental health care specifically. Is it likely to contribute to improved lives for mentally ill people? If so, how?Methods  This qualitative study relies on archival, and to a much lesser extent, informant interview data. Informants were mostly public mental health officials because they are in a position to implement EBP on a large scale and their policies are a matter of public record. Interviews were semi‐structured, held in person and on the telephone, and lasted one to two hours. Archival research included the substantial literature on EBM and EBP plus studies and articles on the practice and policy of U.S. public mental health care.Results  The results of this study were that there exists an extensive, coherent literature critical of EBM and of EBP specifically. Attempts to implement EBP will falter on epistemological and organizational barriers. Still, as a public idea—that more science will bring about better mental health practice—EBP may well serve political purposes, especially in the U.S. public mental health system, where more overtly ideological policies have been inadequate in the past. EBP, as a public idea, has the advantage of ambiguity, accountability, quantifiability, etc.Conclusions  This paper concludes that EBP is growing more influential in public mental health care in the U.S. Its practical strengths, i.e., its improvement of mental health practice, may turn out to be less than its strengths as a public idea in the formulation and dissemination of mental health policy.
Prolactin and Oxytocin Interaction in the Paraventricular and Supraoptic Nuclei: Effects on Oxytocin mRNA and Nitric Oxide Synthase
Authors: Popeski N. , Amir S. , Diorio J. , Woodside B. 
Published: May 2003

AbstractWe investigated the contribution of prolactin and oxytocin to the increase in staining for NADPH‐d and oxytocin mRNA in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) observed at the end of pregnancy, or following a steroid‐priming regimen that mimics the hormonal profile of late pregnant females. Ovariectomized rats received chronic implants of silastic capsules containing oestrogen and progesterone followed by progesterone removal. In experiment 1, oxytocin antagonist (OTA) was administered to rats to investigate whether intranuclear oxytocin release was necessary for NADPH‐d staining. In experiments 2a and b, rats received concurrent treatment with bromocryptine (0.5 mg/day) to suppress endogenous prolactin release, and either systemic prolactin (0.5 mg once daily), or prolactin (2 µg/µl), or vehicle infused twice a day into the third ventricle, or chronic oxytocin infusion (24 ng/day) for 3 days following progesterone removal. Brains were then processed for NADPH‐d histochemistry. In experiment 3, the interaction of prolactin and oxytocin on oxytocin mRNA within the SON and PVN was examined. NADPH‐d staining in the SON and PVN was reduced by the highest dose of the OTA, and by bromocryptine treatment. Central prolactin and oxytocin replacement completely restored NADPH‐d staining in bromocryptine‐treated rats. Finally, both bromocryptine and the OTA suppressed oxytocin mRNA expression and prolactin replacement restored expression levels to that of controls. Together, these data suggest that the increased capacity to produce nitric oxide in the SON and PVN during late pregnancy is dependent on prolactin stimulating oxytocin gene mRNA and hence intranuclear oxytocin release.