bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing biogeographic relationships between North American and Chinese macrofungi
Authors: Mueller Gregory M. , Wu Qiu‐Xin , Huang Yong‐Qing , Guo Shou‐Yu , Aldana‐Gomez Ruth , Vilgalys Rytas
Published: March 2003

Aim

A close biogeographic relationship between the macrofungi of eastern North America and eastern Asia has been documented based on comparisons of species lists. In addition to having a similar species composition, the two regions are reported to share a number of species with putative disjunct distributions. This close biogeographic relationship, however, has rarely been tested within a phylogenetic context. In this paper we examine relationships within three genera, Armillaria, Xerula and Suillus (Fungi, Basidiomycetes, Agaricales) chosen as exemplars of different ecological guilds occupied by macrofungi (plant pathogens, saprobes, mutualists).

Location

Fieldwork for this project centered in eastern North America, Central America, China and Australasia. Material from additional localities were obtained from cooperating herbaria and additional sequences were downloaded from GenBank.

Methods

ITS sequence data were used to construct phylogenies for each genus.

Results

Only one of four tested putative disjunct species, Xerula hispida Halling and Mueller, was supported. Material referable to X. furfuracea (Peck) Redhead, Ginns and Shoemaker from China and North America do not form a monophyletic group. Disjunct populations of Suillus spraguei (Berkeley & Curtis) Kuntze were shown to be paraphyletic. The morphological similarity of the Chinese material to the North American material is likely due to morphological stasis. Finally, morphologically identical material referable to Suillus americanus (Peck) Snell in Slipp and Snell from eastern North America and S. sibiricus (Singer) Singer from China, along with the morphologically similar western North American S. sibiricus, probably represent a single circumboreal taxon.

Main conclusions

The resulting data, while not refuting the hypothesis that there exists a relatively close biogeographic relationship for macrofungi between eastern North America and eastern Asia, suggest that the relationship may not be as close as indicated by morphological data. These results are similar to emerging data from analyses of flowering plants displaying putative eastern North American/eastern Asian disjunct distribution patterns.
Linking abundance, occupancy and spatial structure: an empirical test of a neutral model in an open‐forest woody plant community in eastern Australia
Authors: Falster Daniel S. , Murray Brad R. , Lepschi Brendan J.
Published: March 2003

Aims

We implemented a neutral model of a positive relationship between abundance and distribution (occupancy) to examine how spatial structure influences abundance–occupancy relationships. The spatially explicit neutral model distributes individuals of species randomly and independently of one another in space to produce a positive abundance–occupancy relationship. Using empirical data, we tested whether abundance–occupancy relationships diverged significantly from the theoretical neutral model, and determined whether significant divergences emerged through intraspecific aggregation or over‐dispersion of individuals.

Location

Field work was conducted in open‐forest vegetation of the Black Mountain region in south‐eastern Australia.

Methods

At eight floristically similar sites in open‐forest vegetation, we established a 20 × 20 m census plot and spatially mapped all individuals of each woody species. The abundance and distribution of each species was determined at each site at three spatial scales within the census plot. Observed abundance–occupancy relationships were compared with the spatially explicit neutral model using linear regression techniques. Monte‐Carlo methods using a two dimensional Poisson process were then used to classify the spatial structure of species as random, aggregated or over‐dispersed.

Results

We found consistent evidence among the eight sites for abundance–occupancy relationships to diverge significantly from the neutral model at the three spatial scales within each community. The direction that the slopes of relationships diverged from the neutral model provided consistent evidence that aggregation of individuals within species was responsible for modifying the form of abundance–occupancy associations in this vegetation, a feature most evident with increasing scale.

Main conclusions

Aggregation is not a mechanism that causes positive abundance–occupancy relationships. Under the neutral model of a positive abundance–occupancy relationship, aggregation should be viewed as a mechanism which modifies a pre‐existing relationship, rather than causing a relationship which would not have otherwise existed. In other words, in the absence of aggregation a positive abundance–occupancy relationship would still exist.
Climate and animal distribution: a climatic analysis of the Australian marsupial Trichosurus caninus
Authors: Fischer J. , Lindenmayer D. B. , Nix H. A. , Stein J. L. , Stein J. A.
Published: March 2003

Aim

A detailed bioclimatic analysis was completed for an Australian arboreal marsupial, the mountain brushtail possum Trichosurus caninus. This was done to explore climatic factors underpinning the distribution of the species.

Location

Location data used for bioclimatic modelling comprised of 879 records, covering the entire known range of T. caninus throughout eastern Australia.

Methods

The computer package BIOCLIM was used to generate a bioclimatic profile of T. caninus. Frequency distributions of climatic attributes in the profile were examined using histograms and a pattern analysis (using the computer package PATN) to determine if there were bioclimatically distinct groups of possums.

Results

Initial analyses of bioclimatic attributes of all records split the location data into two discrete groups based on the frequency distribution of ‘mean temperature of the wettest quarter’ of an average year, as this had a discontinuous, bimodal frequency distribution. Pattern analysis produced groupings congruent with this. When analysed separately, the bioclimatic domains of the two groups were geographically discrete. Although many key bioclimatic attributes were similar (particularly those defining light and moisture regimes that relate to vegetation structure), temperature regimes and seasonality of rainfall regime were very different for each group.

Main conclusions

The two groups identified in this study were congruent with two groups established by an earlier multivariate morphometric analysis of T. caninus. Further targeted field research together with genetic analyses, are needed to further investigate the taxonomic significance of findings on (1) the bioclimatic domain(s) and (2) the morphology of T. caninus.
Ecological biogeography of southern polar encrusting faunas
Authors: Barnes David K. A. , De Grave Sammy
Published: March 2003

Aim

To investigate the affinities and similarities between coastal (marine) encrusting faunas along the Andes–Scotia Arc–Antarctic Peninsula mountain chain with a uniform sampling strategy.

Location

Twelve different samples sites were selected on the (southern) South American and (western) Antarctic continents. The sites spanned 25° of latitude along the Andes–Scotia Arc–Antarctic Peninsula mountain chain from Tierra del Fuego to the Ross Sea (Antarctica).

Methods

Encrusting faunal colonists were identified on rocky (boulder/cobble) surfaces constituting a total surface area of 2 m2from each of twelve localities at depths from the intertidal zone to 12 m. Faunal suites of sites were subjected to differing but common modern analyses, Detrended Correspondance Analysis (DCA) andTWINSPAN.

Results

Typically the number of encrusting species increased with depth and decreased with isolation (remote islands, such as South Georgia and Bird Island had depauperate faunas). The proportion of the total fauna constituted by bryozoans, sponges and other taxa changed with site latitude and isolation. Ordination (DCA) of the site species data matrix revealed distinct Patagonian, Falkland and Antarctic groupings. Ordination of just the Antarctic grouping revealed a cline from the northerly and shallower sites to those more southerly and deep.TWINSPANanalysis of the same data set largely supported the ordination. Ordination at generic level showed a high degree of similarity with the species ordination pattern.

Main conclusions

The north/south, deep/shallow, cline found shows distinct faunistic patterning within biogeographic zones. The separation of sites within and outside the Polar Frontal Zone (PFZ) support more classically based historic biogeographic studies. The major difference between the findings of this study was the organization of sites into a cline vs. distinct zones. The simplest explanation for why studies yeild such different findings must lie with the considerable differences in the types of data sets used; historical records or (as here) short‐term, uniform, sampling strategies.
Biogeography of tropical reef fishes: the South Atlantic puzzle
Authors: Joyeux J.‐C. , Floeter S. R. , Ferreira C. E. L. , Gasparini J. L.
Published: March 2003

Aim

To reveal underlying distributional mechanisms of tropical reef fishes in the South Atlantic.

Location

The tropical South Atlantic, with emphasis on the Brazilian province.

Methods

The disjunct distributions of thirty‐five reef fish species occurring in the Brazilian Province were analysed to allow a better understanding of present biogeographical patterns. To avoid potential bias because of taxonomic problems or misidentification, we only included families taxonomically well documented, with conspicuous species, and relatively easy to identify.

Results

The low‐level differentiation between Caribbean and Brazilian species/populations, as well as the presence of restricted populations of a few northern or southern species on the opposite side of the Amazon River, clearly indicate that this barrier to dispersion can be occasionally bridged. Transoceanic dispersal appears to be frequent and to occur along three routes: from the Caribbean to North East Atlantic, from northern Brazil to the Gulf of Guinea, and from Africa to southern Brazil. Intermediate stepping‐stones are apparently not required along transatlantic routes because of the rarity of consecutive colonizations. However, intermediate stopovers are persistently used along short routes. In all cases, the long‐term success of colonists, i.e. the establishment of stable local populations, appears to depend upon ecological factors.

Main conclusions

The puzzling patterns of distribution found in the South Atlantic seem primarily the outcome of allopatric speciation and of the interaction of long distance dispersal abilities and ecological processes. Successfulness of the colonization of remote sites appears to be less dependent from dispersal ability than upon persistence ability or settlement preferences.
Biogeography of the tenebrionid beetles (Coleoptera, Tenebrionidae) on the Aegean Islands (Greece)
Authors: Fattorini Simone
Published: March 2003

Aim

This research aimed to study if a transitional character can be postulated for the tenebrionid beetle (Coleoptera, Tenebrionidae) fauna of the Aegean Islands, and to identify ecological and historical factors responsible for observed patterns.

Location

Eastern Mediterranean, Aegean Islands.

Methods

A total of 32 Aegean Islands and 166 taxa (species and subspecies) were included in this study. In order to assess whether the Aegean tenebrionid fauna is mainly equilibrial or relictual, the importance of different eco‐geographical variables (i.e. area, latitude, longitude, distance to the nearest island, distance to the mainland) in determining species richness and endemicity levels was analysed by using several statistical methods. These included single regressions, multiple regressions, and partial correlations. Cluster analysis, multidimensional scaling (MS) and discriminant function analysis (DFA) were used to quantify the similarities between the islands. Regression lines were used to study variations in the proportion of Balkan and Anatolian species. Parsimony Analysis of Endemicity (PAE) was used to study possible relationships between hierarchical species assemblages and palaeogeographical reconstructions.

Results

Island area accounted for most variability in species number. Distances to the nearest island and to the mainland were not identified as of any statistical importance in affecting species number. The proportion of Balkan taxa sharply decreases from west to east, whereas the Anatolian taxa follow an opposite trend. The proportion of endemic taxa appears uncorrelated with island present isolation, while the proportion of subendemic taxa appears to be affected by present distance to mainland and interisland distances. Cluster analysis, MS and DFA, as well as PAE, revealed a clear faunal discontinuity between the western and central Aegean Islands on one side, and the islands close to the Anatolian coast on the other side. This discontinuity, consistent with the persistence (from Messinian to Pleistocene) of a sea barrier between these two groups of islands, strongly supports the importance of Pleistocene island configurations in determining present distributional patterns.

Main conclusions

The tenebrionid fauna of the Aegean Islands appears to be relictual. Most of the tenebrionid species have probably colonized the Aegean Islands by means of land‐bridges during Pleistocene falls in the sea level. The palaeogeography of Pleistocene island groupings is identified as responsible for present levels of endemicity and distributional patterns. An overall transitional character can be observed for the tenebrionid fauna in the study area. However, in accordance with the persistence of a deep sea barrier between the western and the eastern islands, these two groups appear to harbour very distinct faunas.
The biology of insularity: an introduction
Authors: Drake Donald R. , Mulder Christa P. H. , Towns David R. , Daugherty Charles H.
Published: March 2003

Insular environments, ranging from oceanic islands to fragments of once‐contiguous natural systems, have long been used by biologists to test basic principles of ecology, evolution and biogeography. More recently, insular environments have figured prominently in conservation ecology, where the aim has usually been to conserve species or assemblages unique to isolated habitats. Improving the level of communication among the evolutionary biologists, theoretical ecologists and conservation biologists who study insular biotas will work to the benefit of all. This volume was inspired by a recent conference on the ecology of insular biotas, in which participants from a wide range of disciplines came together to compare ecological processes across a variety of taxonomic groups inhabiting a wide range of isolated environments. In this introduction, we point out the themes underlying these very diverse contributions. First we elaborate on the value of islands for elucidating processes underlying ecosystem functioning, population dynamics of reintroduced species, and restoration of disturbed habitats, and emphasize those areas where the use of islands could be expanded. The second section focuses on the link between ecology and evolutionary processes in insular systems and includes examples from oceanic islands, naturally patchy habitats and recently fragmented habitats. The third section illustrates some of the ways that invasive alien species on oceanic islands affect plant–animal mutualisms, particularly seed dispersal and pollination. The final section, on consequences of habitat fragmentation, focuses mainly on studies that describe the consequences that fragmentation has for plants and animals as they are forced into artificially insular environments. We close with a study that points out the differences among types of insular systems and identifies gaps in our knowledge of insular biotas, particularly the importance of explicitly incorporating patch type, age and patch–matrix contrasts in research. Finally, we recommend a greater emphasis on linking ecological theory and applied research, and improving communication between those who ask basic ecological questions and those who use insular systems for conservation.
Fluctuating asymmetry as a bio‐indicator in isolated populations of the Taita thrush: a Bayesian perspective
Authors: Lens Luc , Van Dongen Stefan
Published: March 2003

Aim

We examined whether developmental instability can be used as a bio‐monitoring tool in the endangered Taita thrush (Turdus helleriL.) through the measurement of individual levels of fluctuating asymmetry in tarsus length. Because estimates of the association between developmental instability, stress and fitness derived from traditional regression are biased, we compared parameter estimates obtained from likelihood based analysis with those obtained from a Bayesian latent variable model.

Location

Taita thrushes were captured and measured in three isolated cloud forest fragments located in the Taita Hills of south‐east Kenya.

Methods

We applied mixed‐effects regression with Restricted Maximum Likelihood parameter estimation (performed with SAS version 8.0) and Bayesian latent variable modelling (performed with WINBUGS version 1.3 and CODA version 0.4) to estimate unbiased levels of developmental instability and to model relationships between developmental instability and body condition in 312 Taita thrushes.

Results

Likelihood and Bayesian analyses yielded highly comparable results. Individual levels of developmental instability were strongly inversely related to body condition in the subpopulation with the lowest average condition. In contrast, both variables were unrelated in two other subpopulations with higher average condition. Such heterogeneity in association was in the direction expected by developmental theory, given that higher condition suggests more benign ambient conditions. The estimated levels of body condition in the three subpopulations did not support their presumed ranking in relation to environmental stress. Developmental instability and body condition are therefore believed to reflect different aspects of individual fitness.

Main conclusions

Variation in developmental homeostasis, either modelled as observable variable (fluctuating asymmetry) or latent variable (developmental instability), appears a useful indicator of stress effects in the Taita thrush. Because relationships between environmental stress and developmental instability may depend on the extent to which stress‐mediated changes in other components of phenotypic variation are correlated, the study of trait asymmetry should preferably be combined with that of other measures of trait variability, such as trait size or organismal condition.
Important aspects of nursing care in surgical wards as expressed by nurses
Authors: IDVALL EWA , ROOKE LISELOTTE
Published: March 2003

• The aim of this study was to find out clinical nurses' perceptions of important aspects of nursing care that might have an impact on quality of care in surgical wards.

• A qualitative approach using focus group interviews was used.

• The data analysis revealed 15 categories of important aspects of care which could be condensed into two dimensions, here called `prerequisites' (i.e. staffing, routines and attitudes) and `elements of performance' (i.e. detecting and acting on signs and symptoms and acting on behalf of the patients). These aspects could be a starting point for developing quality indicators.

• Carper's four fundamental patterns of knowing were used to make a theoretical interpretation, and three of them were identified.
Teaching sociology to nurses: exploring the debate
Authors: WILLIAMSON GRAHAM R.
Published: March 2003

• This article reviews literature on the current debate concerning teaching sociology to nurses.

• The debate is limited because it does not take into account the work of Donald Schön, or Anthony Giddens.

• The article also discusses theories of adult education which support teaching sociology in nurse education.

• Sociology is essential for nurses, because it can help to develop an understanding and analysis of the context and substance of nursing practice.
Operational and resource management of an RCT: some of the pitfalls and lessons learned
Authors: DOLAN GINA , BROOMFIELD JACKIE , LEWITH GEORGE , WATKINS ALAN
Published: March 2003

• Nurses frequently fulfil important functions within a research team involved in clinical trials. This paper describes the challenges inherent in developing and managing a large clinical trial involving the evaluation of homoeopathy and asthma.

• Teamwork, a clear and comprehensive understanding of the research protocol, marketing the project, and the ability to manage human resources within both a primary and secondary care environment are all essential aspects of clinical research.

• Our experience in establishing and managing this project has suggested to us that a high standard of clinical research demands an open approach to problem‐solving as well as the realization that efficient research is as much about the management of people as it is about scientific rigour.
The decision to resuscitate: older people’s views
Authors: Phillips Karen , Woodward Valerie
Published: March 2003

• The aim of this study was to explore how a healthy sample of the older population feel about resuscitation and the decision not to resuscitate certain patients.

• Their views were sought on whether a Do Not Resuscitate decision is appropriate in certain circumstances, whom they think should be involved in the decision, whether they think patients should be consulted, and if they would like to be involved in the decision themselves.

• Two focus groups were held in a day care setting in order to collect data, and a thematic analysis was conducted.

• Participants thought that a Do Not Resuscitate decision should be discussed with patients and also with relatives if appropriate.

• However, there was ambivalence about whether individuals would like to be involved personally in such a decision because of the anxiety this would produce.
A comparison of the nursing competence of graduates and diplomates from UK nursing programmes
Authors: Bartlett Helen P. , Simonite Vanessa , Westcott Elizabeth , Taylor Heidi R.
Published: March 2003

• This paper reviews the literature on nursing competence measurement and reports the results of a comparative quantitative study of the competencies of Project 2000 diplomates and BA (Hons) Adult Nursing graduates from two UK nursing programmes.

• The findings reveal that graduates appear to overcome any initial limitations and become more competent than the diplomates in certain areas.

• Attention to social awareness and participation is necessary in both pre‐registration programmes, whilst greater attention could be given to graduates’ leadership and management development.

• Diplomates need support in their professional development if they are to achieve the same level of competence as graduates during the first post‐qualifying year.

• There are implications for the level of support afforded to qualifying nurses in their first staff positions; preceptorship programmes could be an important means of assisting newly qualified staff to gain confidence. More research on nurse competencies with larger samples drawn from programmes across the UK is needed.
Technological competence as a fundamental structure of learning in critical care nursing: a phenomenological study
Authors: Little Christine V.
Published: March 2003

• Post‐registration education programmes are frequently informed by nationally agreed curriculum frameworks. Although these aim to promote comparability between similarly focused clinical courses, inconsistencies have recently been identified across a range of critical care curricula. This suggests that broad‐based frameworks may be insufficiently sensitive to local learning needs.

• This study was concerned with the extent to which the curriculum met the learning needs of 10 post‐registration critical care students and, in particular, aimed to explore the meaning of learning to the students themselves.

• The study revealed technological competence to be a necessary foundation to the development of clinical practice and this is discussed from a philosophical perspective which allows the nature of contemporary nursing practice to be reconceptualized.

• It is argued that curriculum development for clinically based, post‐registration courses can be constructively informed by local consultation and that phenomenological study can complement more traditional approaches often relied upon in educational research.
Elders’ perceptions of formal and informal care: aspects of getting and receiving help for their activities of daily living
Authors: Roe Brenda , Whattam Maxine , Young Heather , Dimond Margaret
Published: March 2003

• A purposive and convenience sample of 16 women and four men receiving informal and formal care for their activities of daily living either at home or institutions in Southeast Washington, USA was interviewed.

• Qualitative findings related to asking for help, getting and receiving help, interpersonal aspects of receiving help, and met and unmet needs are reported.

• Some seniors found it more difficult to ask for and accept help and there were gender differences, with men tending to adopt a more logical and pragmatic approach while women viewed receiving help as a loss of independence and an invasion of privacy. Intimacy and nudity were also threats for women.

• Three styles of adjustment and acceptance were identified within the data and related to positive acceptance, resigned acceptance and passive acceptance.

• There appeared to be a relationship between independence and control, with elders losing some independence but retaining control through choice, payment and involvement in decision making.

• Reciprocity was found to bring added value to relationships between care providers and elders, with a rhythm and symmetry developing in relationships where needs were known, anticipated and met.

• Seniors should be encouraged to plan for their future and to find out about local help and services available to them in advance of their requiring any assistance.
Relocation stress in critical care: a review of the literature
Authors: Mc KINNEY AIDÍN A. , MELBY VIDAR
Published: March 2003

• Transfer to the ward following a period in intensive care may cause stress for patients.

• A review of the literature reveals that this phenomenon has been described in a number of different ways, such as transfer stress, transfer anxiety, translocation syndrome and, more recently, relocation stress.

• This paper reviews the various concepts before arriving at a more operational definition of the phenomenon.

• It attempts to reveal what causes this phenomenon and to what extent it exists.

• Patients' responses to transfer are identified and the physical and psychological problems that have been associated with discharge from intensive care are discussed.

• Lists of interventions that the literature suggests may reduce or prevent this phenomenon from occurring are reviewed.

• Recommendations for practice development and further research are made.
Research as a catalyst for change: the transition from student to Registered Nurse
Authors: ROSS HELEN , CLIFFORD KEVIN
Published: March 2003

• This paper outlines the qualitative findings of a study exploring the transition from student to Registered Nurse and the catalytic effect of the way in which newly registered nurses are prepared for this role change.

• The study explored the experiences of one cohort of students undertaking the pre‐registration Advanced Diploma in Nursing Studies at the University of Sheffield.

• Data were collected pre‐qualification and post‐qualification in order to compare the expectations and reality of the transition period. Two key aspects emerged, one relating to the experience of students undertaking the final module of the course and the other to preceptorship once qualified. These two areas of practice have been the focus of development following dissemination of the research findings in the local NHS Hospitals.

• The study suggests that the transition period remains very stressful for some nurses, because of both pre‐registration educational issues and the level of support received once qualified. Careful planning of the student experience in the final year and addressing inconsistencies within the preceptorship programmes of newly qualified nurses are needed. The study is stimulating change in the local NHS hospitals, with the aim of enhancing the overall experience of student nurses and newly qualified staff alike.
Being a palliative care nurse in an academic hospital: a qualitative study about nurses' perceptions of palliative care nursing
Authors: Georges Jean‐Jacques , Grypdonck Mieke , De Casterle Bernadette Dierckx
Published: March 2003

•  The original philosophy of palliative care emphasizes the importance of the integration of compassion and medical science. The meaning palliative care nurses assign to their relationships with patients has been described in several studies.

•  This qualitative research was undertaken in order to elicit the way nurses working on a palliative care ward in an academic hospital perceive their role and gain insight into the problems they encounter.

•  The findings present two different perceptions held by nurses about the nature of their work. The first, the more prominent, is ‘striving to adopt a well‐organized and purposeful approach as a nurse on an academic ward’; the second is ‘striving to enhance the well‐being of the patient’.

•  Nurses should be supported in the development of their palliative care approach and be assisted in reflecting on their practice in terms of a model of ‘reflective practice’ and in the development of ‘moral imagination’.
A qualitative study of coping in the early stage of acute traumatic hand injury
Authors: Gustafsson Margareta , Persson Lars‐Olof , Amilon Anders
Published: March 2003

• Twenty patients with acute traumatic hand injury were interviewed 8–20 days after the day of the accident.

• The aim of the study was to identify coping strategies, defined as thoughts or actions used by the hand‐injured patients to manage stress factors and resulting emotions in the early stage. Stress factors were reported in an earlier study.

• The analyses of the interviews followed the first steps in the analytical process described in a modified model of grounded theory.

• Eleven different coping strategies were identified in the interviews. By ‘comparing with something worse’, ‘positive thinking’, ‘relying on personal capacity’, ‘distancing’ and ‘distracting attention’ the patients tried to play down the seriousness of the problem or situation. Other coping strategies used by the hand‐injured were ‘accepting the situation’, ‘seeking social support’, ‘maintaining control’, ‘solving practical problems by oneself’, ‘pain‐relieving actions’ and ‘active processing of the trauma experience.’

• The findings of the study show how important it is to identify the patient's own way of coping with a stressful illness situation in order to give adequate psychosocial support.
Self‐directed learning in simulation‐based discovery environments
Authors: De Jong T. , Van Joolingen W. R. , Swaak J. , Veermans K. , Limbach R. , King S. , Gureghian D.
Published: March 2003

SIMQUEST is an authoring system for designing and creating simulation‐based learning environments. The special character of SIMQUEST learning environments is that they include cognitive support for learners which means that they provide learners with support in the discovery process. In SIMQUEST learning environments, a balance is sought between direct guidance of the learning process and sufficient freedom for learners to regulate the learning process themselves. This paper describes the basic mechanisms of the SIMQUEST learning and authoring environments. The functionality authors have in providing the learner with guidance and some of the experiences on how authors use these opportunities and learners employ the cognitive support are reported.
Biotechnology in the textile/clothing industry – a review
Authors: Rowe Helen D.
Published: March 2003

Summary: This paper focuses on the use of biotechnology in the textile/clothing industry by identifying where and how such processes are already established and considers the latest developments, either in the research stage or in the early stages of commercialization. It has been found that biotechnology systems are already well known to those involved in fabric preparation, particularly as regards desizing. Enzymes used in detergent formulations have also been successfully used for the past 30–40 years. Most recent commercial advances have been in fabric finishing processes where handle modifications to cotton fabrics in particular are fast becoming established. Cutting‐edge research falls in the areas of fibre modification and the generation of new fibres from natural sources, such as natural polyester from bacteria. The isolation of DNA from the shaft of hair fibres and the encoding of detectable specific antigens to designer labels is providing new ways of helping to combat fraud and counterfeit in the fashion trade. The treatment of textile effluent continues to be a major problem to the industry, but here, biotechnological developments in other industries are helping to provide some answers.
Population genetics, molecular markers and the study of dispersal in plants
Authors: Ouborg N. J. , Piquot Y. , Van Groenendael J. M.
Published: March 2003

1 Long‐distance dispersal events are biologically very important for plants because they affect colonization probabilities, the probabilities of population persistence in a fragmented habitat, and metapopulation structure. They are, however, very difficult to investigate because of their low frequency. We reviewed the use of molecular markers in the population genetics approach to studying dispersal. With these methods the consequences of long‐distance dispersal are studied, rather than the frequency of the dispersal events themselves.

2 Molecular markers vary, displaying different amounts of variation and different modes of inheritance: they may be either dominant or codominant, and may or may not be subjected to genetic recombination. Use of markers has inspired the development of maximum likelihood techniques that take the evolutionary history of alleles into account while estimating gene flow.

3 Inferring seed dispersal rates from indirect measurements of gene flow involves three steps: (i) quantifying genetic differentiation among populations and using this to estimate the rate of gene flow; (ii) producing a genetic dispersal curve by regressing geographical distance among populations against the amount of gene flow; and (iii) separating seed‐mediated from pollen‐mediated gene flow, by comparing differentiation in nuclear vs. cytoplasmic molecular markers. In this way, potentially very low levels of gene flow can be detected.

4 The indirect approach is based on a number of assumptions. The validity of each assumption should be assessed by independent methods or the estimates of gene flow and dispersal should be mainly used in a comparative context. In metapopulations, with frequent extinction and colonization, the relationship between genetic differentiation and gene flow is not straightforward, and other methods should be used.

5 Highly variable molecular markers, especially microsatellites, have facilitated a direct genetic approach to measuring gene flow, based on parental analyses.

6 The population genetic approach provides different information about dispersal than ecological methods. Thus population genetic and ecological methods may supplement each other, and together lead to a better insight into the dispersal process than either of the methods on its own.
Slug herbivory as a limiting factor for the geographical range of Arnica montana
Authors: Bruelheide Helge , Scheidel Ulrich
Published: March 2003

1
 We tested whether slug herbivory is a factor restricting the rare perennial Arnica montana to high elevations in the Harz mountains, Lower Saxony.

2
 In one experiment we artificially increased the mollusc population density in plots containing native Arnica montana populations. Leaf loss and damage to Arnica increased significantly, whilst damage to other plant species in the same plots was unaffected by mollusc density.

3
 A second experiment examined damage by molluscs of transplanted Arnica montana plants at three different altitudes. Whilst damage to Arnica was negligible at 610 m a.s.l. (where natural populations occur), molluscs removed 8% of Arnica leaf area at 385 m a.s.l. and 75% at 180 m a.s.l. At the two lower sites, protective caging of Arnica plants significantly reduced the amount of leaf tissue consumed by molluscs. The impact of mollusc herbivory on Arnica montana therefore appears to increase with decreasing altitude.

4
 Despite the weak relationship between leaf damage to Arnica montana and mollusc abundance, periods of peak mollusc activity may well coincide with those phases in Arnica life history that are most sensitive to tissue removal by herbivores.

5
 Our results support the hypothesis that polyphagous herbivores play a major role in limiting the distribution of preferred plant species. We discuss how selective herbivory may influence the distribution of Arnica montana populations in these grassland communities.
Competition and herbivory during salt marsh succession: the importance of forb growth strategy
Authors: Dormann Carsten F. , Van Der Wal Rene , Bakker Jan P.
Published: March 2003

1  Despite much debate about their importance, only a few field studies have evaluated the intensity of competition and herbivory.

2
 
Artemisia maritima, Atriplex portulacoides and Plantago maritima, three plant species which are common in European temperate salt marshes, were transplanted into different successional stages (15, 30 and 45 years old) of a temperate salt marsh. Biomass of each transplant was measured as the response variable to treatments that manipulated competition and the level of herbivory.

3
 All species were shown to be negatively influenced by both competition and herbivory, with competition being in general of greater importance than herbivory. No change could be detected during succession in the intensity of either competition or herbivory. Their combined impact, however, increased over succession for Atriplex, although no trend was observed for the other two species.

4
 Both biomass and allocation patterns reflected further adaptations of these salt‐tolerant species to environmental stress and biotic interactions present in the salt marsh. Plantago, which is the best adapted to salinity, was shown to be markedly affected by competition and herbivory. Atriplex showed less response to herbivory and little response to competition, to which it is well adapted. The grazing‐deterrent Artemisia was influenced by herbivory only as a seedling.
Effects of migratory geese on plant communities of an Alaskan salt marsh
Authors: Zacheis Amy , Hupp Jerry W. , Ruess Roger W.
Published: March 2003

We studied the effects of lesser snow geese (Anser caerulescens caerulescens) and Canada geese (Branta canadensis) on two salt marsh plant communities in Cook Inlet, Alaska, a stopover area used during spring migration. From 1995 to 1997 we compared plant species composition and biomass on plots where geese were excluded from feeding with paired plots where foraging could occur.

Foraging intensity was low (650–1930 goose‐days km−2) compared to other goose‐grazing systems.

Canada geese fed mainly on above‐ground shoots ofTriglochin maritimum, Puccinelliaspp. andCarex ramenskii, whereas the majority of the snow goose diet consisted of below‐ground tissues ofPlantago maritimaandTriglochin maritimum.

Plant communities responded differently to goose herbivory. In the sedge meadow community, where feeding was primarily on above‐ground shoots, there was no effect of grazing on the dominant speciesCarex ramenskiiandTriglochin maritimum. In the herb meadow community, where snow geese fed onPlantago maritimaroots and other below‐ground tissues, there was a difference in the relative abundance of plant species between treatments. Biomass ofPlantago maritimaandPotentilla egediiwas lower on grazed plots compared with exclosed, whereas biomass ofCarex ramenskiiwas greater on grazed plots. There was no effect of herbivory on total standing crop biomass in either community. The variable effect of herbivory onCarex ramenskiibetween communities suggests that plant neighbours and competitive interactions are important factors in a species’ response to herbivory. In addition, the type of herbivory (above‐ or below‐ground) was important in determining plant community response to herbivory.

Litter accumulation was reduced in grazed areas compared with exclosed in both communities. Trampling of the previous year’s litter into the soil surface by geese incorporated more litter into soils in grazed areas.

This study illustrates that even light herbivore pressure can alter plant communities and affect forage availability.
The effect of plant population size on the interactions between the rare plantGentiana cruciataand its specialized herbivoreMaculinea rebeli
Authors: Kéry Marc , Matthies Diethart , Fischer Markus
Published: March 2003

Many rare plant species are restricted to small isolated populations in which fitness may be reduced because of inbreeding, environmental and demographic stochasticity, and reduced pollination. However, specialist herbivores are less likely to be present in such populations because of higher probabilities of herbivore extinction and lower rates of colonization, and may therefore affect fitness only in larger plant populations.

We studied the relationships between the size of populations of the endangered grassland plantGentiana cruciataand the probability of occurrence and population size of its specialist herbivore, the endangered butterflyMaculinea rebeli, and their effects on plant size, fruit herbivory and seed production.

The 29G. cruciatapopulations studied ranged in size from 1 to 337 genets and 18 of them supported aM. rebelipopulation.M. rebelipopulations were both more likely and larger in largerG. cruciatapopulations. Estimated adult herbivore populations were small, ranging from 1 to 42 individuals, with a median of 11. We conclude that the conservation ofM. rebelirequires the conservation of largeG. cruciatapopulations.

Although large populations ofG. cruciataproduced more flowers, a greater proportion of their fruits were attacked by herbivores. Fruit herbivory, which considerably decreased the number of seeds per fruit, appears to have been caused largely byMaculinea. The number of seeds both per fruit and per genet significantly decreased with the number ofM. rebelieggs per genet. The overall independence ofG. cruciataseed production from population size may result from the opposing effects on fruit production and herbivory.

Our study suggests that complex interactions between different trophic levels may determine the population dynamics of rare species. Furthermore, small population size may have both negative and positive effects on the fitness of endangered species.
Water use trade‐offs and optimal adaptations to pulse‐driven arid ecosystems
Authors: Schwinning Susanne , Ehleringer James R.
Published: March 2003

We introduce a hydraulic soil‐plant model with water uptake from two soil layers; one a pulse‐dominated shallow soil layer, the other a deeper soil layer with continuous, but generally less than saturated soil moisture. Water uptake is linked to photosynthetic carbon assimilation through a photosynthesis model for C3 plants.

A genetic algorithm is used to identify character suites that maximize photosynthetic carbon gain for plants that experience a particular soil moisture pattern. The character suites include allocation fraction to stem, leaves and shallow root, stem capacitance and stem water storage capacity, maximal leaf conductance and sensitivity of leaf conductance to plant water potential, and a critical soil water potential at which shallow roots cease to transfer water.

We find that if pulse water is a more important water source than deeper soil water in the environment, optimal phenotypes lean towards adaptations that maximize pulse water use (small root : shoot ratio, predominantly shallow root system, high leaf conductance with high stomatal sensitivity to plant water status). If deeper soil water is more important, phenotypes lean towards adaptations that maximize deeper soil water use (large root : shoot ratio, predominantly deep root system, lower leaf conductance with low stomatal sensitivity). Stem succulence is adaptive only when deeper soil water is unavailable.

From among the continuum of derived phenotypes, four phenotypes are selected that resemble the character suites of winter annuals, drought‐deciduous perennials, evergreen perennials and stem succulents. Under common conditions, these phenotypes reproduce many of the responses to drought and water pulse observed in their respective life‐form counterparts. The comparison also highlights the differences in plant life‐form sensitivity to summer and winter drought conditions.

Based on these results, we discuss the possible role of annual precipitation patterns in shaping plant adaptations and determining the plant composition of arid and semi‐arid environments.
Frugivory at Juniperus communis depends more on population characteristics than on individual attributes
Authors: García Daniel , Zamora Regino , Gómez José M. , Hódar José A.
Published: March 2003

We investigated the spatio‐temporal variation in the interactions between the juniper Juniperus communis and its vertebrate frugivores (avian dispersers of Turdus spp. and predatory rodents Apodemus sylvaticus) in the Mediterranean mountains of south‐east Spain.

 Frugivore activity was evaluated at six sites and for 3 years, in relation to both plant reproductive traits (plant size, cone crop and cone size) and characteristics of the immediate environment (distance to the nearest female, abundance of perches, fruiting environment and habitat).

 Plant characteristics and levels of frugivory varied strongly among the six populations. Cone production, cone size and frugivory also differed significantly among years for the same population. Avian frugivory was only occasionally affected by density of cones per plant, abundance of perches or abundance of other fruiting species, or by habitat. Rodent predation was positively related only to the density of cones per plant and then only in two sites.

 Levels of both avian frugivory and rodent predation significantly increased in populations with higher cone production.

 Both groups of vertebrate frugivores responded to the spatio‐temporal variation in cone abundance at a regional scale, discriminating more between juniper populations than between individual plants within a population. The outcome of interactions with frugivores at the individual plant level thus proved more dependent on the whole‐population characteristics than on individual attributes.