bluuebunny/crossref_metadata_2025 huggingface dataset:
Phylogeography in coastal marine animals: a solution from California?
Authors: Dawson Michael N
Published: March 2003

Aim

Recently discovered deep phylogenetic gaps in coastal California marine taxa are geographically discordant with the provincial biogeographic boundary at Point Conception. This discordance runs contrary to the phylogeographic hypotheses that were derived from studies of coastal marine taxa in south‐eastern North America. Here, I investigate the nature of the discrepant phylogeographic and biogeographic patterns in coastal California.

Location

Coastal south‐western North America.

Methods

The scientific literature describing the phylogeography and biogeography of coastal California taxa was reviewed. Data describing life‐history characteristics, habitat, and degree of phylogeographic structure were extracted and compared. The geographical distribution of phylogenetic breaks was compared with regional biogeographic data.

Results

All taxa were genetically variable. Those with greater dispersal ability generally had less phylogeographic structure. Although few taxa had very limited dispersal ability, many exhibited phylogeographic breaks within the California Transition Zone, a region of gradual species replacement between Oregonian and Californian biogeographic provinces. The most precisely resolved phylogeographic breaks were geographically concordant with peaks in the distribution of edge‐effect species, which are strong indicators of environmental discontinuities, or ecotones. Moreover, these phylogeographic gaps, edge‐effect species, and ecotones coincide geographically with Late Pleistocene faunal discontinuities and probable long‐term physical barriers to gene flow.

Main conclusions

Contrary to prior inference, phylogeographic patterns in coastal California marine taxa are consistent with the phylogeographic hypotheses. The concordance of phylogeographic and biogeographic patterns in the coastal marine faunas of south‐eastern and south‐western North America, and also the Indo‐Pacific, suggests that the phylogeographic hypotheses are generally applicable to many coastal marine settings. As such, they provide a framework for investigating and comparing patterns of evolution in disparate coastal marine faunas.
Ichthyofaunistic biogeography of the Japan (East) Sea: the comparison of various rank taxa for zoning
Authors: Kafanov Alexander I. , Volvenko Igor V.
Published: March 2003

Aim

The aim of the present study is the analysis of the latitudinal distribution of taxonomic richness (number of genera and families) of ichthyofauna at the western and eastern coasts of the Japan Sea for the purpose of identification of natural boundaries, and subsequent comparison with results obtained using the distribution analysis of species richness.

Location

Japan Sea (Korean – East Sea).

Methods

All statistical procedures were based on well‐tried and widely accepted numerical methodology and the STATISTICA program package. For identifying the statistically meaningful (non‐random) maxima and minima in taxonomic richness (n), arithmetic differences in the number of taxa at ith and i − 1th geographical latitudes and the measurements of as well as residuals in polynomial trends and clustering (Ward’s method) of genera and family lists, were analysed. The relationship between the number and the scope of taxa was approximated by Zipf–Pareto–Mandelbrot frequency distribution: p(N)=k/N1+k, where p(N) is a relative number of taxa, each of them includes N taxa of the next lower rank; k is a constant. The determination of the constant was made by a nonlinear estimation procedure using quasi‐Newton algorithms approximating the second‐order derivatives of the loss function to guide the search for estimation of the minimum/best parameter estimates.

Results

The comparison between all the types of analysis gives similar results and the boundaries of faunistic units identified from taxonomic lists of species, genera and families are practically coincident at herein accepted regional biogeographical scaling. The relation between the number and the scope of taxa is approximated satisfactorily by Zipf–Pareto–Mandelbrot model.

Main conclusions

The differences obtained by other authors in the results of zoning by species, genera and family lists are largely pre‐determined by commonly used quantitative analytical methods: theoretical‐and‐graph methods and clustering procedures. The distribution analysis of species and superspecific taxa gives closely approaching results for relatively high latitudes and sharply diverging results for relatively low latitudes. The Zipf–Pareto–Mandelbrot distribution describing the relation between the number and the scope of taxa uniquely pre‐supposes definite quantitative relationships between various rank taxa. So, the predicted species number S may be calculated on observed genera number G. If the values of species/genus ratios (S/G) are tabulated for various G, it turns out that the relationship S/G shows an almost linear variation (between 1.78 and 2.50) in the interval between twenty and 1000 species, abruptly rising with further increase in the length of species list. Therefore, the S/G ratios widely used and considered important by various ecological and biogeographical concepts are a statistical artefact. Variation analysis of taxonomic richness is a basic operational procedure in faunistic biogeography.
Holocene landscape development and human impact in the Connemara Uplands, Western Ireland
Authors: Huang Chun Chang
Published: March 2003

Aim

Aim Investigate: (1) the role of human impact in shaping the landscape and particularly the initiation of blanket bog; (2) the short‐lived abrupt changes and their causation; (3) the phenomenon of large‐scale upland peat erosion to answer the question of when and why erosion of upland blanket peat commenced in the Connemara uplands.

Location

Lough Maumeen in the Maumeen Gap, Connemara, Western Ireland.

Methods

Pollen, sedimentary analysis and 14C dating on the lake sediment cores.

Results

Pollen diagrams, charcoal fragments, bulk and dry densities, mineral content (or loss‐on‐ignition), whole core magnetic susceptibility, specific magnetic susceptibility for the core profile.

Main conclusions

Pine‐dominated woodland developed from 9250 BP. Human activities effected the deforestation between 5050–4000 BP. Peat bog initiated on the wet hollow ground in the gap during the elm decline. The major expansion of blanket bog landscape in the upland commenced at 4000 BP following immediately the Taxus decline. Human impact was the dynamic force responsible for the destruction of the woodland and the formation of blanket bog in the upland. Three episodes of short‐lived erosion events were identified between 8650–8400 BP, 5450–5250 BP, and 600–200 cal. BP, respectively. They are very different from each other in their causation. Large‐scale peat erosion is a recent phenomenon. It has been caused by intensive sheep grazing, which has been extended to the upland blanket bogs since the late eighteen century.
A conceptual framework for studying species composition in fragments, islands and other patchy ecosystems
Authors: Watson David M.
Published: March 2003

Aim

I propose and develop a new classification system to explain diversity patterns in habitat fragments, equally applicable to islands and other inherently patchy ecosystems. My primary goal is to provide an inclusive model to improve the comparability of studies and enhance future efforts to synthesize their findings, yielding a generalized basis for understanding species composition in patchy ecosystems.

Results

Differentiating islands from fragments and incorporating patch age and patch: matrix contrast, eight classes of patch are distinguished, spanning a range of geographical features. To compare studies of diversity patterns among and between patch types, patch biota are divided into three categories based on their origin—relict species (present before fragmentation), matrix‐derived species and interpatch dispersers. Applying this novel scheme to existing data, the effects of insularization are synthesized. Direct comparisons among fragments revealed broad similarity in the long‐term effects of habitat fragmentation compared with highly divergent patterns in younger landscapes (<200 years). Holding patch: matrix contrast and age constant, fragments and islands were compared. Despite initial differences in community assembly, the biota of islands and fragments converge in several properties over time, as diversities stabilize and patch biotas become distinct from the surrounding matrix.

Main conclusions

Although necessarily broad, this framework provides an explicit context within which to test forty‐four specific predictions regarding the distribution of diversity in patchy landscapes and thereby gain a clearer understanding of the long‐term biological consequences of insularization. I propose that the fragments‐as‐islands analogy be revisited, potentially yielding valuable insight into the long‐term future awaiting anthropogenically altered ecosystems.
Evaluating the effectiveness of two teaching strategies for patients diagnosed with hypertension
Authors: Zernike Wendy , Henderson Amanda
Published: March 2003

• This study investigated whether a structured patient‐centred education programme was more effective than the normal ad hoc information that patients receive in improving their knowledge of hypertension whilst in hospital.

• Forty patients were assessed to determine their knowledge level regarding the management of risk factors related to hypertension.

• A pre‐test was performed shortly after admission to hospital. Twenty patients in the test group received a structured education programme, and 20 patients in the control group received the usual ad hoc information. Two post‐tests were performed, one at the time of discharge and the other approximately 8 weeks after discharge, to determine the change in knowledge levels.

• Comparison of the pre‐ and post‐tests of the test group revealed a significant increase in knowledge level at the time of discharge from hospital. Patients were found to retain this new knowledge at 8 weeks and 1 year after discharge. No significant difference was found for the control group.

• This study has shown that a structured approach to health education is more effective in improving patients' knowledge about their condition than relying on the ad hoc information that patients traditionally receive during their hospitalization.
Patient's perceptions of bedside handovers
Authors: Cahill Jo
Published: March 2003

• The bedside handover is a universal phenomenon in nearly every type of care setting. It has become the chief arena for the intershift handover in contemporary nursing practice. Published literature investigating patients' viewpoints on the location of the bedside handover is sparse.

• The overall aim of this study is to describe and provide an analysis of patients' perceptions of the bedside handover.

• A grounded theory approach to data collection and data analysis was employed to capture surgical patients' views about the bedside handover.

• The analysis tentatively suggests the existence of three categories that describe the patients' perceptions of the bedside handover. ‘Maintaining a Professional Distance’, ‘Establishing Professional Sharing’ and ‘Maintaining Patient Safety.’
Identification of infection in granulating wounds by registered nurses
Authors: CUTTING KEITH F.
Published: March 2003

•The purpose of the study was to investigate the methods used by registered nurses to identify infection in granulating wounds.

•Although this research was completed a few years ago recent observations confirm that the findings remain relevant and that accurate identification of wound infection continues to present a challenge.

•This study also set out to compare the subjects' and author's decisions on the infected status of the wounds.

•The author used criteria previously developed by Cutting & Harding (1994).

•Decisions made by the author were found to have a high level of accuracy when compared against a microbiological assay of the wounds.
School nurses’ operational modes and ways of collaborating in caring for child abusing families in Finland
Authors: Paavilainen Eija , Åstedt‐Kurki Päivi , Paunonen Marita
Published: March 2003

• The purpose of the study was to explicate and conceptualize school nurses’ work and working methods while caring for child abusing families. Child abuse in the family refers to physical or psychological abuse, sexual abuse or neglect by parents or other caregivers.

• Data were collected using semi‐structured interviews with broad themes from Finnish school nurses (n=20). School nurses were selected so that the sample represented a varied experience of school health services in various schools, differing in size, environment and number of pupils. Data were analysed by using qualitative content analysis.

• The analysis resulted in a description of school nurses’ operational modes with child abusing families. These were the ‘active and firm’ mode and the ‘passive and uninvolved’ mode. In addition, the study describes school nurses’ collaboration with other professionals working in school, mainly teachers.

• The primary goal of school nurses was to promote the child’s well‐being as effectively as possible, whereas caring for the whole family was of secondary importance. The difficulty in taking care of families with problems was shown in different operational modes, especially in ‘passive’ nurses.

• The results of the study can be used to plan and develop nursing education and the work of school nurses. Nurses need more knowledge about child abuse and working with families in school healthcare. It is important that nurses are trained to work with families who abuse their children.
Sexual problems in men with prostate cancer in comparison with men with benign prostatic hyperplasia and men from the general population
Authors: Jakobsson Liselotte , Lovén Lars , Hallberg Ingalill Rahm
Published: March 2003

• In a questionnaire study, men with prostate cancer (n=155) or benign prostatic hyperplasia (n=131) identified more sexual problems than did men from the general population (n=129). Sexual dysfunction was acknowledged regarding sexual pleasure and attraction, erectile function and sexual satisfaction and sexual performance.

• Lowered rates of sexual desire, pleasure and attraction were found when comparing their situation in recollection of pre‐treatment situation to the current situation. Lower intercourse frequency and sexual satisfaction were also found.

• Medication, masturbation and artificial aids to achieve erection were not used as substitutes for shortcomings of erectile function either by men with prostate cancer and benign prostatic hyperplasia nor by their partners.

• There seemed to be a lack of information about the illness and treatment consequences for sexual life, including what physical dysfunction to expect after surgery and also what possible help to expect to compensate for the shortcomings.
Stressors and coping methods among chronic haemodialysis patients in Hong Kong
Authors: Mok Esther , Tam Bonnie
Published: March 2003

• The purpose of the study was to determine the stressors and coping methods of chronic haemodialysis patients in Hong Kong. Relationships among treatment‐related stressors, coping methods and length of time on haemodialysis were explored.

• Fifty subjects completed the Haemodialysis Stressor Scale (HSS) and Jalowiec Coping Scale (JCS).

• Results revealed that limitation of fluid was the most frequently identified stressor, followed by limitation of food, itching, fatigue and cost.

• The most common coping methods are ‘accepted the situation because very little could be done’, followed by ‘told oneself not to worry because everything would work out fine’ and ‘told oneself that the problem was really not that important.’ It was found that the traditional philosophies of the Chinese – Confucianism, Buddhism, and Taoism – share an approach to the understanding and management of life stressors as different from that adopted by Western philosophies.

• The findings of this study can further facilitate nurse practitioners in providing support, information, and alternative solutions when assisting patients in coping with long‐term haemodialysis.
Protecting strategies used by sufferers of catastrophic illnesses and injuries
Authors: Dewar Anne
Published: March 2003

• The purpose of this research was to describe strategies used by sufferers of catastrophic illnesses and injuries.

• Participants were adult men and women with a variety of serious illnesses and injuries.

• Qualitative research approaches to data collection and data analysis, using grounded theory methods were employed.

• Descriptions of the participants indicate that several strategies are used; this discussion focuses on strategies to protect themselves from further suffering.

• Situations where participants use protecting strategies are identified and described.

• The findings indicate how care‐recipients try to lessen the burden on their care‐givers and to protect them from the stress of the sufferer’s problems.
Enhancing lives through the development of a community‐based participatory action research programme
Authors: KOCH TINA , SELIM PAM , KRALIK DEBBIE
Published: March 2003

• A community‐based participatory action research (PAR) programme that has spanned 5 years is discussed in this article. A primary healthcare philosophy requires research in this practice setting and supports the way healthcare is ideally organized within an integrated team and supported by a community network that includes not only the healthcare workers and service providers but also the community as partners.

• The principles driving three PAR inquiries are described: the development of a model for prevention of workplace violence; working with clinicians towards improving wound management practice; and management of continence for community‐dwelling women living with multiple sclerosis.

• Participatory action research is a potentially democratic process that is equitable and liberating as participants construct meaning in the process of group discussions.

• We conclude that the cyclical processes inherent in PAR promote reflection and reconstruction of experiences that can lead to the enhancement of people's lives, either at an individual or community level, or both.
A method and tool for the design of educational multimedia material
Authors: Lewis R. , Koper E.J.R.
Published: March 2003

Abstract This paper deals with the problem of the specification of the pedagogic design of interactive multimedia and specific telematics applications developed for use in education. A method to specify the design and a supporting tool (SHOC‐TOOL) are described. The idea is that the use of such a method and tool can make the development process more efficient and can lead to a more professional approach to the pedagogic design of educational software in general. Resulting design specifications can be assessed for completeness, allow for comparisons among designs and are relatively easy to read for others than the designer himself. The method and the tool both stimulate the re‐use of existing design and code segments. SHOC‐TOOL is described along with several examples from real practice. The paper concludes with a discussion of the experience of its introduction and use.
Monitoring the on‐line behaviour of distance learning students
Authors: Wilson T. , Whitelock D.
Published: March 2003

Abstract Projects using Computer Mediated Communication (CMC) are becoming of interest to all academic institutions world‐wide. STILE (Students' and Teachers' Integrated Learning Environment) is one such project which used a CMC environment with one hundred and ten students and nine tutors in the United Kingdom and Europe. The participants were on‐line for a period of ten months in 1995. The course selected was Fundamentals of Computing (M205) which catered for both technical and nontechnical students. The provision of these facilities enabled distance learning students to avail themselves of better communication with their tutor and fellow students and to download extra electronic course materials. They could also send their computer code, created for the course, around electronically. This paper discusses student reactions to the on‐line collaborative experience and reports on their collaborative behaviour with respect to the conferencing environment.
A multimedia‐enhanced collaborative learning environment
Authors: Looi C‐K. , Ang D.
Published: March 2003

Abstract The proliferation of the Internet has brought about the notion of online virtual communities. One enabling technology for online communities is multiuser environments such as Multi‐User Dimensions (MUDs) and Object‐Oriented MUDS (MOOs). These text‐based collaborative learning environments have recently have been integrated with the World Wide Web, thus harnessing the graphics and multimedia‐rich environments available therein. Learners can directly experience, manipulate, and create objects in their rich multimedia form. MUDs and MOOs are augmented with synchronous collaboration technology that provided simultaneous control and viewing of shared documents and applications. In this paper, we describe a multimedia‐enhanced MOO system called SpaceALIVE! and our experiences from a pilot project involving Singapore students who use SpaceALIVE! as a collaborative learning environment are reported.
Learning physics with a computer algebra system
Authors: Savelsbergh E.R. , De Jong T. , Ferguson‐Hessler M.G.M.
Published: March 2003

Abstract  To become proficient problem‐solvers, physics students need to form a coherent and flexible understanding of problem situations with which they are confronted. Still, many students have only a limited representation of the problems on which they are working. Therefore, an instructional approach was devised to promote students' understanding of these problems and to support them in forming associations between problem features and solution methods. The approach was based on using the computer algebra softwareMathematicaas a tool for problem solving and visualisation. An electrostatics course module was implemented based on this instructional approach, and this module was compared with a usual paper‐and‐pencil based one. Learning outcomes for both courses were not significantly different. The experimental course was found to impose a high cognitive load on the students. Based on the outcomes, proposals are made for ways in which the course could be improved.
Sociodemographic factors associated with obesity in the USA
Authors: Nayga Rodolfo M.
Published: March 2003

Abstract: This paper examines the impact of sociodemographic factors on the likelihood of an individual being obese using a cross‐sectional survey of Americans and logit analysis. Results of the logit model indicate that those with children, black people, women, those with a lower education level, those from the Midwest, and those who have a lower level of physical activity during leisure time are more likely to be obese than others. Considering the extent of the obesity problem in the United States, these results should be used as a guide in the design of food policy and health education programmes concerning obesity. The results could also be used by marketers of health food and drug products in their marketing campaigns.
Towards a rationale for integrating consumer and citizenship education
Authors: McGregor Sue
Published: March 2003

Despite the importance of consumer education and citizenship education in contemporary societies, there has been little attempt to bring together the studies of these two fields to understand the developments in which they share an interest. After defining the parameters of consumer education and citizenship education, this paper will begin to develop a rationale for integrating consumer education and citizenship education, striving to identify synergies that could lead to revised consumer education curricula such that people are prepared to be citizens first and consumers second; that is, consumer‐citizens.
Young consumers’ food preferences within selected sectors of the Hospitality Spectrum
Authors: Brown Karen , McIlveen Heather , Strugnell Christopher
Published: March 2003

In society, young consumers are influenced by an array of factors within their home, school and social environments. The adolescent period is one in which the individual becomes a more independent consumer, exerting increased degrees of independence and a subsequent freedom of preference. Such independence may be particularly apparent within the social environment, despite young consumers generally being categorized under the ‘family market’, within the Hospitality Spectrum. The aim of the study was to analyse young consumers’ food preferences within the home, school and social environments, with particular reference to the role of the Hospitality Spectrum. Young consumers for the study, are defined as being between 11 and 16 years, segmented into two age groups: 11–13 years and 14–16 years. The selected sectors of the Hospitality Spectrum which were studied, were the fast food service and school canteen sectors. In order to fulfil the research aim and objectives, a range of research instruments and analysis techniques were used. The results of the study to date would illustrate that tentative steps have been taken within the school and fast food sectors, to bridge the ‘gaps’ between business supply and consumer preferences. Gender differences were found in food selections within school canteens and fast food establishments, with females more likely to select ‘British’ styled fast foods at school and males more likely to select ethnic foods at fast‐food establishments. No significant differences were found between the two age segments. It is vital that the increasingly important role of the young consumer segment is recognized, in particular considering them as individuals rather than as a part of the ‘total’ family consumer package. However, in market segmentation young consumers are an important consumer group and it must not be overlooked that they will be the future adult consumers. The Hospitality Spectrum must therefore treat this group with respect for the consumer service industry to achieve its full potential. The results of this Northern Ireland study indicates that although the young consumer segment is viewed as important within the selected sectors of the Hospitality Spectrum, the extent of their full potential has yet to be recognized.
Establishment, competition and the distribution of native grasses among Michigan old‐fields
Authors: Foster Bryan L.
Published: March 2003

1 In this study the potential role of competition in influencing the distribution of three displaced native perennial grasses across complex gradients of plant productivity and species composition was investigated in Michigan old‐fields. To do this plant removal and propagule addition experiments were conducted at nine old‐field sites to examine the effects of living plant neighbours and litter on seedling establishment and growth of target species in relation to community biomass.

2 For two target species, Andropogon gerardi and Schizachyrium scoparium, living plant neighbours suppressed establishment from seed at most sites, and suppressed the growth of transplants at all sites.

3 Plant litter strongly inhibited the seedling establishment of both Andropogon and Schizachyrium at sites of high community biomass and litter accumulation, but had little impact on the growth rate of transplants at any of the sites.

4 The total suppressive effect of the plant community on seedling establishment and transplant growth of both Andropogon and Schizachyrium increased in magnitude in a non‐linear fashion with community biomass. These effects increased in magnitude more rapidly across sites of low to medium biomass than sites of medium to high biomass.

5 The results suggest that these native grasses may be restricted to low productivity habitats within this landscape because of strong competitive interference with establishment by the existing vegetation in the most productive sites.
Controls over the accumulation and decline of a nitrogen‐fixing lichen,Stereocaulon vulcani, on young Hawaiian lava flows
Authors: Kurina Lianne M. , Vitousek Peter M.
Published: March 2003

1 The abundance of the nitrogen‐fixing lichen colonist,Stereocaulon vulcani, was determined on a matrix of sites on the north‐east slope of Mauna Loa volcano, Hawaii.

2 Rates of lichen colonization and accumulation were highest at low elevation, where conditions are warm and wet, but lichens persisted longest in the colder, drier, higher elevation sites.

3 An analysis of lichen abundance data from Mauna Loa's north‐east slope, together with data from sites located on different aspects of Mauna Loa volcano and Kilauea volcano, showed that lichen accumulation on the youngest lava flows was limited most strongly by precipitation rather than by temperature.

4 Fertilization experiments showed that at high elevation (1800 m) rates of both nitrogen and carbon uptake were more strongly nutrient‐limited in lichens living on an older lava flow (142 years) than in lichens living on a younger lava flow (52 years). Decline ofS. vulcaniat high elevation may therefore be related to nutrient limitation.

5 An 80% reduction in direct light on the younger flow at low elevation decreased rates of nitrogen assimilation and nitrogen content significantly, suggesting that lichen decline here is most probably due to light limitation as a result of shading by vascular plants.
Geographical variation in predictive seedling emergence in a perennial desert grass
Authors: Smith Steven E. , Riley Emily , Tiss John L. , Fendenheim Debra M.
Published: March 2003

1 Mechanisms that link germination and emergence to environmental cues associated with seedling success (predictive germination) would be expected to evolve when seedlings have a greater mortality risk than seeds, but may be less important in perennial plants than in annual plants.

2 We investigated variation in predictive seedling emergence among divergent populations of a short‐lived perennial desert grass, Digitaria californica, from sites that differed in climatic and edaphic factors. This species is native to environments in which the amount and duration of adequate soil moisture may control germination and seedling establishment success.

3 We utilized a special irrigation system that permits application of a range of amounts of water within a single experiment in a glasshouse. Emergence data were subjected to probit and survival analyses to describe differences among the populations in response to applied water.

4 Significant variation in predictive emergence was shown to exist among populations of D. californica when measured as amount of water required for 50% emergence following 3 days of water application, or as time required to achieve this level of emergence. Both climatic and soil characteristics were important with populations that originated from sites with less summer precipitation, and soils with higher water‐holding capacity tended to have lower water requirements for emergence.

5 The report demonstrates the existence of subtle variation in predictive emergence among populations of a perennial grass representing a relatively narrow range of ecological amplitude. It also establishes the usefulness of line‐source irrigation and probit analysis procedures in studying seedling emergence behaviour.
The demographic role of soil seed banks. II. Investigations of the fate of experimental seeds of the desert mustard Lesquerella fendleri
Authors: Cabin Robert J. , Marshall Diane L. , Mitchell Randall J.
Published: March 2003

1 Although poorly studied and understood, the post‐dispersal movements and fates of seeds may affect critically the subsequent structure of plant communities, particularly in desert ecosystems where seeds can be the most abundant or only viable form of many plant species. We investigated the fate of experimental seeds of the desert mustard Lesquerella fendleri by examining seed dispersal and predation, and by quantifying the proportion of seeds that germinated and survived as seedlings in three different microsites within a New Mexico desert shrubland.

2 We found very limited seed dispersal but strong density‐dependent seed predation by rodents. There was a significant and consistent microsite effect in the proportion of soil seeds germinating and seedlings surviving to the end of the experiments. We did not find a consistent microsite effect for soil seed persistence, but did find a positive correlation between soil seed persistence and soil seed germination. Overall, these results indicate that seed predation may strongly affect the distribution of the seed bank, and that the abiotic environment may largely determine the extent to which soil seed populations in turn affect the distribution of emerging surface plants.

3 We present a seed fate model that synthesizes the results of the present and previous empirical investigations of the Lesquerella study system. This diagram illustrates how interactions among the abiotic environment, microsite variation and seed genotypes can determine which soil seeds successfully germinate and establish into the surface plant population. We suggest that the demography of desert surface plant populations may depend more on the time between seed inputs and the longevity of these seeds in the soil than on the amount of seeds produced at any one point in time and space.
Population dynamics of Vulpia ciliata: regional, patch and local dynamics
Authors: Watkinson Andrew R. , Freckleton Robert P. , Forrester Lisa
Published: March 2003

1 Data on the population dynamics of the annual grass Vulpia ciliata were collected at three levels, from the scale of the regional population down to small (10 × 10 cm) patches. We use these data to explore the degree to which fine scale processes influence large scale patterns of abundance.

2 Populations were characterized by their persistence, despite their small size. The mean half‐life of populations was estimated to be around 45 years. Most populations are small (a few m2) in area, with only a few as large as a hectare in size.

3 Population regulation occurs as a consequence of density‐dependent seedling recruitment. This reduces population growth by up to 87%. The nature of this density dependence appeared to be essentially the same across sites and years.

4 Interactions with perennial vegetation also significantly affected population dynamics, through reducing seedling recruitment and survival, and on average depressed population growth by a further 30% at one site and by up to 96% in another population.

5 Plants were aggregated and densities were positively spatially autocorrelated. This tends to buffer patches against extinction. Mean seed production per plant, was also significantly spatially autocorrelated; however, the strength of this was minor.

6 Data on small‐scale extinction showed that disturbance is an important determinant of the distribution of numbers of plants within subplots. Comparison of the distribution of subplot densities with the results of a spatial simulation model suggested that disturbance at a relatively large scale (at least 20 × 20 cm) impacts on dynamics at the population scale.

7 An integro‐difference equation model for patch expansion shows that populations are constrained to an area no larger than around 100 m2 on a time‐scale relevant to the dynamics of this species (about 20 years).

8 We conclude that the most characteristic features of dynamics at the regional scale, namely the persistence and very small spatial size of individual populations, can be readily explained by processes operating at small spatial scales.
Plant diversity affects culturable soil bacteria in experimental grassland communities
Authors: Stephan André , Meyer Andrea H. , Schmid Bernhard
Published: March 2003

1 Utilization of carbon sources by culturable soil bacteria can be assessed with BIOLOG microtiter plates (contain 31 C sources). We used this technique to investigate bacterial community structure at various levels of plant diversity. Plant diversity levels were replicated and we investigated the influence of three plant functional groups, grasses, legumes and non‐leguminous herbs, as well as the influence of individual plant species.

2 Catabolic activity and catabolic diversity of culturable soil bacteria were used to estimate their density (abundance) and functional diversity, respectively. Both increased linearly with the logarithm of plant species number and with the number of plant functional groups in experimental grassland ecosystems. These effects may have been caused by an increased diversity and quantity of material and energy flows to the soil. They may also have been mediated by increased diversity of soil microhabitats via a stimulation of the soil fauna.

3 The presence of particular plant species or functional groups in the different experimental communities stimulated the activity and functional diversity of the culturable soil bacteria in addition to their contribution via plant diversity. The legumeTrifolium repenshad the strongest effect and may be regarded as a keystone species with regard to plant–microbial interactions in the systems studied.
Palaeovegetation‐model comparisons, climate change and tree succession in Scandinavia over the past 1500 years
Authors: Cowling Sharon A. , Sykes Martin T. , Bradshaw Richard H. W.
Published: March 2003

We assess the robustness of a 1500‐year palaeoclimate data base and forest gap model in simulating northern Scandinavian boreal forest succession since ad 500. We also evaluate trends in species abundance in a nemoral woodland in southern Scandinavia by comparing modelling results to palaeoecological data.

Simulated biomass trends for Picea, Pinus and Betula growing at Penningholmen (northern Sweden) are strikingly similar to those observed in the local pollen record, particularly in the replication of the early Little Ice Age (LIA) decline in Betula and the late‐LIA dieback of Picea and Pinus.

LIA decreases in Betula may therefore be partly due to the effects of climate on its competitive interactions with Pinus, as well as the previously proposed effects of insect herbivory.

Simulations of Draved Forest (western Denmark), suggest that Tilia is under‐represented in modern‐day Scandinavian nemoral woodlands, and consequently that the present dominance of Fagus probably reflects strong human–plant interactions from as early as the beginning of the 17th century.

This study highlights the importance, despite general limitations associated with vegetation models, of model‐data comparisons for understanding mechanisms and processes underlying past forest succession, and emphasizes the usefulness of forest models for reconstructing climate influences on past vegetation.
Population dynamics and stage structure in a haploid‐diploid red seaweed,Gracilaria gracilis
Authors: Engel Carolyn , Åberg Per , Gaggiotti Oscar E. , Destombe Christophe , Valero Myriam
Published: March 2003

Many red seaweeds are characterized by a haploid‐diploid life cycle in which populations consist of dioecious haploid (gametophyte) and diploid (tetrasporophyte) individuals as well as an additional diploid zygote‐derived sporangium (carposporophyte) stage. A demographic analysis ofGracilaria gracilispopulations was carried out to explore and evaluate the population dynamics and stage structure of a typical haploid‐diploid red seaweed.

 FourG. gracilispopulations were studied at two sites on the French coast of the Strait of Dover. Survival, reproduction and recruitment rates were measured in each population for up to 4 years. Eight two‐sex stage‐based population projection matrices were built to describe their demography.

 All four populations were characterized by high survival and low recruitment rates. Population growth rates (λ) were similar between populations and between years and ranged from 1.03 to 1.17. In addition, generation times were found to be as long as 42 years.

 Sex and ploidy ratios were variable across populations and over time. Female frequencies ranged from 0.31 to 0.59 and tetrasporophyte frequencies from 0.44 to 0.63. However, in most cases, the observed population structures were not significantly different from the calculated stage distributions.

 Eigenvalue elasticity analysis showed that λ was most sensitive to changes in matrix transitions that corresponded to survival of the gametophyte and tetrasporophyte stages. In contrast, the contribution of the fertility elements to λ was small. Eigenvector elasticity analysis also showed that survival elements had the greatest impact on sex and ploidy ratios.
The higher availability of N and P in lime‐poor than in lime‐rich coastal dunes in the Netherlands
Authors: Kooijman A. M. , Besse M.
Published: March 2003

1 Measurements of above‐ground productivity, plant nutrient levels,in situmineralization and litter decomposition in four localities differing in soil chemical conditions were used to assess the availability of N and P in Dutch coastal dune grasslands.

2 P‐availability is regulated by soil chemical conditions and seems to be a key factor regulating biomass production, whereas N‐availability seems to be determined by litter input from this biomass, and thus indirectly controlled by P.

3 Contrary to expectation, N‐availability is much higher in acid soils (with low rates of decomposition and high soil C : N ratios) than in calcareous soils (with high decomposition and low C : N ratios). Similar results have been reported from other ecosystems and may be due to a lower microbial N‐demand at low rates of decomposition, increasing the amount of N left over for the vegetation.

4 In contrast to ‘conventional wisdom’, low‐degradable litter may be a good plant strategy to improve the ecosystem recycling of nutrients and increase their availability. This may at least partly explain the success ofAmmophila arenariain lime‐ and iron‐poor dunes.
Spatially realistic plant metapopulation models and the colonization–competition trade‐off
Authors: Higgins Steven I. , Cain Michael L.
Published: March 2003

Results from patch‐occupancy metapopulation models indicate that a trade‐off between competitive and colonization abilities is necessary for species to coexist in patchy environments. However, such models are often based on unrealistic ecological assumptions, such as global dispersal and no local population dynamics.

We develop a plant metapopulation model that allows us to sequentially relax unrealistic assumptions about dispersal and local population interactions. We use our model to examine the extent to which the conclusions of analytical, patch‐based coexistence models depend on their assumptions.

We found that the need for an inferior competitor to be a superior colonizer was reduced by using a dispersal kernel to distribute seeds, and totally removed by relaxing the assumption of instantaneous competitive displacement. These results hold for annual or perennial plants with or without seedbanks, for global, local and stratified dispersal, for delayed competitive exclusion, two‐way competition and neighbourhood competition, and for landscapes where habitat patches are either adjacent or disjunct.

We conclude that the results of patch‐occupancy metapopulation models differ greatly from results of models that incorporate more realistic assumptions about dispersal and local population dynamics. As a result it may be premature to base biodiversity management and policy on the results of patch‐occupancy models.
Demographic consequences of inbreeding and outbreeding inArnica montana: a field experiment
Authors: Luijten Sheila H. , Kéry Marc , Oostermeijer J. Gerard B. , Den Nijs Hans (J.) C. M.
Published: March 2003

The genetic constitution of populations may significantly affect demography. Founder populations or isolated remnants may show inbreeding depression, while established populations can be strongly adapted to the local environment. Gene exchange between populations can lead to better performance if heterozygosity levels are restored (heterosis), or to reduced performance if coadapted gene complexes are disrupted (outbreeding depression).

Five populations of the self‐incompatible perennialArnica montana(Asteraceae) were analysed for the demographic consequences of inbreeding and of intra‐ and interpopulation outcrossing, using both small and large populations as donors for the latter. We analysed seed production and seed weight and monitored growth, survival and flowering of offspring introduced as seeds and as 4‐week‐old seedlings in a 4‐year field experiment.

Reduced seed set after selfing was probably due to the self‐incompatibility system rather than to inbreeding depression. There was a significant increase for seed set after interpopulation crosses, which resulted from the alleviation of low mate availability in one of the small populations.

Significant inbreeding depression was observed for growth rates of plants introduced as seedlings. We found significant heterosis for flowering probability of plants introduced as seeds, but for plants introduced as seedlings, heterosis for seedling size and flowering probability was only marginally significant. Outbreeding depression was not observed.

The results of this study are important for reinforcement measures in small, remnant populations. Significant differences among populations for all measured fitness components suggest that reinforcement is best achieved using material from several populations.

The observed higher survival of seedlings as compared with seeds suggests that it is better to plant individuals than to sow. Sowing, however, is easier and cheaper, and was more likely to eliminate poorly adapted genotypes before they contribute to the next generation.
Reasons for not reporting adverse incidents: an empirical study
Authors: Vincent Charles , Stanhope Nicola , Crowley‐Murphy Margaret
Published: March 2003

Abstract: A previous study (Stanhope et al. 1998) established that staff in two obstetric units reported less than a quarter of designated incidents to the units’ risk managers. A questionnaire was administered to 42 obstetricians and 156 midwives at the same two obstetric units, exploring the reasons for low rates of reporting. Questions concerned their knowledge of their unit's incident reporting system; whether they would report a series of 10 designated adverse obstetric incidents to the risk manager; and their views on 12 potential reasons for not reporting incidents. Most staff knew about the incident‐reporting system in their unit, but almost 30% did not know how to find a list of reportable incidents. Views on the necessity of reporting the 10 designated obstetric incidents varied considerably. For example, 96% of staff stated they would always report a maternal death, whereas less than 40% would report a baby's unexpected admission to the Special Care Baby Unit. Midwives said they were more likely to report incidents than doctors, and junior staff were more likely to report than senior staff. The main reasons for not reporting were fears that junior staff would be blamed, high workload and the belief (even though the incident was designated as reportable) that the circumstances or outcome of a particular case did not warrant a report. Junior doctors felt less supported by their colleagues than senior doctors. Current systems of incident reporting, while providing some valuable information, do not provide a reliable index of the rate of adverse incidents. Recommended measures to increase reliability include clearer definitions of incidents, simplified methods of reporting, designated staff to record incidents and education, feedback and reassurance to staff about the nature and purpose of such systems.