bluuebunny/crossref_metadata_2025 huggingface dataset:
Independent evolution of migration on the South American landscape in a long‐distance temperate‐tropical migratory bird, Swainson's flycatcher (Myiarchus swainsoni)
Authors: Joseph Leo , Wilke Thomas , Alpers Deryn
Published: May 2003

Aim  To understand the evolution of long‐distance temperate–tropical migration in a South American bird, Swainson's flycatcher (Myiarchus swainsoni).

Methods  A total of 842 base pairs of the mitochondrial DNA genes ATPase 8 and 6 were sequenced from forty‐nine individuals of the M. swainsoni complex from most of its range. Analyses measured the phylogenetic signal in the data, and tools of population genetics, phylogeography and phylogeny were used to interpret the evolution of the bird and its migration on the South American landscape.

Results  Migratory populations in the M. swainsoni complex are not each other's closest relatives. The migratory subspecies M. s. swainsoni, which breeds in south‐eastern South America, is not closely related to the rest of the complex. The remaining migratory populations of the subspecies M. s. ferocior and two intergrade populations are extremely closely related to non‐migratory populations with which they form a well‐supported clade despite substantial morphological differentiation from each other. Within this clade of migrants and non‐migrants, net divergence across 4000 km of lowland South America is zero and most diversity is distributed among individuals not populations. Mismatch analyses and significant values of Tajima's D and Fu's Fs suggest the clade has undergone a very recent range expansion. Migration and the shifts of breeding distribution that accompanied its evolution evolved twice within what has recently been considered the polytypic species M. swainsoni. Furthermore, these shifts of range probably occurred at very different times as parts of different southward ‘pulses’ of humid, Amazonian taxa.

Main conclusions  Evolution of temperate‐tropical migration in the M. swainsoni complex has been spatio‐temporally layered on the South American landscape. The analysis cautions that the historical biogeography underlying a single present‐day migration system need not have been driven by a single set of environmental factors operating at one time. We suggest directions for further study of ecology and demography in zones of apparent contact between various migratory and non‐migratory populations.
Critique of parsimony analysis of endemicity as a method of historical biogeography
Authors: Brooks Daniel R. , Van Veller Marco G. P.
Published: May 2003

Aim Assess the value of parsimony analysis of endemism as either ana priori(cladistic) and ana posteriori(phylogenetic) method of historical biogeography.

Location World‐wide.

Methods Parsimony analysis of endemicity (PAE) and Brooks parsimony analysis (BPA).

Results Parsimony analysis of endemicity is capable of finding correct and unambiguous area relationships only under scenarios of vicariance in combination with non‐response to vicariance or extinction. An empirical comparison between PAE and BPA, using the poeciliid fish generaHeterandriaandXiphophorus, demonstrates that PAE fails to document much of the historical complexity in this relatively simple system.

Main conclusions Thea prioriassumptions of PAE are far more restrictive than those made by othera priorimethods, limiting its utility as a method of cladistic biogeography. The inability of PAE to detect perfect vicariance or biogeographical histories involving dispersal, renders it unsuitable as a method of phylogenetic biogeography.
Host introductions and the geography of parasite taxonomic diversity
Authors: Poulin Robert , Mouillot David
Published: May 2003

Aim  Geographical variation in parasite diversity is examined among populations of fish in their original heartland and in areas where they have been introduced. The diversity in heartland and introduced populations is contrasted, and also compared with the expectations of a null model.

Location  Data on the parasite communities of two salmonid fish species were obtained: the rainbow trout Oncorhynchus mykiss in its British Columbia heartland and in introduced populations in North America, Great Britain, South America and New Zealand; and the brown trout Salmo trutta in heartland populations from Great Britain, and in introduced populations in North America, South America and New Zealand.

Methods  The average taxonomic distinctness and its variance were computed for each parasite community, and used as measures of the taxonomic diversity of parasite species in each fish population. Observed values of taxonomic distinctness were also compared with those expected if each community was a random selection from the world list of parasite species known for each of the two host species.

Results  Few parasite communities departed from the expectations of the null model, i.e. few had a taxonomic diversity of parasites greater or lower than that expected from a random selection of parasite species. However, these departures were not more or less likely among heartland fish populations than among introduced ones. In both fish species, parasite communities in introduced populations tended to be a little more taxonomically diverse than in the heartland populations.

Main conclusions  Overall, the results suggest that the accumulation of parasite species in introduced hosts over short (ecological) periods of time can result in parasite assemblages that are just as, or even more, taxonomically diverse than those developed over much longer (evolutionary) time frames in the host species geographical heartland. This finding highlights the importance of ecological factors in parasite biodiversity in addition to coevolutionary processes.
Relative importance of environment, human activity and spatial situation in determining the distribution of terrestrial mammal diversity in Argentina
Authors: Real Raimundo , Márcia Barbosa A. , Porras Daniela , Kin Marta S. , Márquez Ana L. , Guerrero José C. , Javier Palomo L. , Justo Enrique R. , Mario Vargas J.
Published: May 2003

Aim The partition of the geographical variation in Argentinian terrestrial mammal species richness (SR) into environmentally, human and spatially induced variation.

Location Argentina, using the twenty‐three administrative provinces as the geographical units.

Methods We recorded the number of terrestrial mammal species in each Argentinian province, and the number of species belonging to particular groups (Marsupialia, Placentaria, and among the latter, Xenarthra, Carnivora, Ungulates and Rodentia). We performed multiple regressions of each group's SR on environmental, human and spatial variables, to determine the amounts of variation explained by these factors. We then used a variance partitioning procedure to specify which proportion of the variation in SR is explained by each of the three factors exclusively and which proportions are attributable to interactions between factors.

Results  For marsupials, human activity explains the greatest part of the variation in SR. The purely environmental and purely human influences on all mammal SR explain a similarly high proportion of the variation in SR, whereas the purely spatial influence accounts for a smaller proportion of it. The exclusive interaction between human activity and space is negative in carnivores and rodents. For rodents, the interaction between environment and spatial situation is also negative. In the remaining placental groups, pure spatial autocorrelation explains a small proportion of the variation in SR.

Main conclusions  Environmental factors explain most of the variation in placental SR, while Marsupials seem to be mainly affected by human activity. However, for edentates, carnivores, and ungulates the pure human influence is more important than the pure spatial and environmental influences. Besides, human activity disrupts the spatial structure caused by the history and population dynamics of rodents and, to a lesser extent, of carnivores. The historical events and population dynamics on the one hand, and the environment on the other, cause rodent SR to vary in divergent directions. In the remaining placental groups the autocorrelation in SR is mainly the result of autocorrelation in the environmental and human variables.
Shapes and functions of species–area curves: a review of possible models
Authors: Tjørve Even
Published: May 2003

Aim  This paper reviews possible candidate models that may be used in theoretical modelling and empirical studies of species–area relationships (SARs). The SAR is an important and well‐proven tool in ecology. The power and the exponential functions are by far the models that are best known and most frequently applied to species–area data, but they might not be the most appropriate. Recent work indicates that the shape of species–area curves in arithmetic space is often not convex but sigmoid and also has an upper asymptote.

Methods  Characteristics of six convex and eight sigmoid models are discussed and interpretations of different parameters summarized. The convex models include the power, exponential, Monod, negative exponential, asymptotic regression and rational functions, and the sigmoid models include the logistic, Gompertz, extreme value, Morgan–Mercer–Flodin, Hill, Michaelis–Menten, Lomolino and Chapman–Richards functions plus the cumulative Weibull and beta‐P distributions.

Conclusions  There are two main types of species–area curves: sample curves that are inherently convex and isolate curves, which are sigmoid. Both types may have an upper asymptote. A few have attempted to fit convex asymptotic and/or sigmoid models to species–area data instead of the power or exponential models. Some of these or other models reviewed in this paper should be useful, especially if species–area models are to be based more on biological processes and patterns in nature than mere curve fitting. The negative exponential function is an example of a convex model and the cumulative Weibull distribution an example of a sigmoid model that should prove useful. A location parameter may be added to these two and some of the other models to simulate absolute minimum area requirements.
How does landscape context contribute to effects of habitat fragmentation on diversity and population density of butterflies?
Authors: Krauss Jochen , Steffan‐Dewenter Ingolf , Tscharntke Teja
Published: May 2003

Aim Studies on habitat fragmentation of insect communities mostly ignore the impact of the surrounding landscape matrix and treat all species equally. In our study, on habitat fragmentation and the importance of landscape context, we expected that habitat specialists are more affected by area and isolation, and habitat generalists more by landscape context.

Location and methods The study was conducted in the vicinity of the city of Göttingen in Germany in the year 2000. We analysed butterfly communities by transect counts on thirty‐two calcareous grasslands differing in size (0.03–5.14 ha), isolation index (2100–86,000/edge‐to‐edge distance 55–1894 m), and landscape diversity (Shannon–Wiener: 0.09–1.56), which is correlated to percentage grassland in the landscape.

Results A total of 15,185 butterfly specimens belonging to fifty‐four species are recorded. In multiple regression analysis, the number of habitat specialist (n = 20) and habitat generalist (n = 34) butterfly species increased with habitat area, butz‐values (slopes) of the species–area relationships for specialists (z = 0.399) were significantly steeper compared with generalists (z = 0.096). Generalists, but not specialists, showed a marginally significant increase with landscape diversity. Effects of landscape diversity were scale‐dependent and significant only at the smallest scale (landscape context within a 250 m radius around the habitat). Habitat isolation was not related to specialist and generalist species numbers. In multiple regression analysis the density of specialists increased significantly with habitat area, whereas generalist density increased only marginally. Habitat isolation and landscape diversity did not show any effects.

Main conclusions Habitat area was the most important predictor of butterfly community structure and influenced habitat specialists more than habitat generalists. In contrast to our expectations, habitat isolation had no effect as most butterflies could cope with the degree of isolation in our study region. Landscape diversity appeared to be important for generalist butterflies only.
Regional and local variation of spider assemblages (Araneae) from coastal grey dunes along the North Sea
Authors: Bonte D. , Criel P. , Van Thournout I. , Maelfait J.‐P.
Published: May 2003

Aim This study aims to determine the underlying causes of local and regional patterns of variation in community structure of spiders in coastal grey dunes, and especially whether ecological time constrains the species composition in young and isolated grey dune habitats.

Location The study was conducted in coastal dunes from northern France (Boulonnais, Nord‐Pas‐de‐Calais), Belgium (Flemish coastal dunes) and the Netherlands [Amsterdam Water Supply (AWD) dunes and Dunes from the Provincial Water Company North‐Holland].

Methods Spiders were collected with pitfall traps in twenty‐eight grey dune patches in the four areas under investigation. Species composition and environmental parameters (vegetation structure, distance to the sea and the patch‐edge, eolic dynamics and lime richness) were determined. Assemblage composition was related to the regional and local environmental factors with the Primer software package to determine the assemblage‐determining parameters. Differences in species presence were analysed as a function of their habitat preference and distribution range.

Results Differences in grey dune spider assemblage structure can mainly be attributed to differences in local sand dynamics and the region. Species from dynamic dunes are mainly present in grey dunes from Belgium and France, while species from non‐dunal xerothermic habitats (chalk grasslands and heathland) occur in both the Boulonnais and the north Holland dune region. These species are absent from geologically young or other xerotherm habitat isolated Flemish coastal dunes.

Main conclusion The data show that regional variation in spider assemblage composition results from local landscape characteristics (dynamics in the dune area), the latitude and the connectivity to non‐dunal xerothermic habitats. The strong and moderate geological isolation of dune areas from the Flemish coast and the AWD dunes, respectively, results in the absence of (at least some) species that are primarily bound to heathland and/or chalk grassland. This indicates the importance of ecological time for the assemblage structure. The limited dispersal capacity of the heathland and/or chalk grassland species is probably the main reason for their absence.
Morphological variability and developmental instability in subpopulations of the Eurasian badger (Meles meles) in Denmark
Authors: Pertoldi Cino , Bach Lars A. , Madsen Aksel Bo , Randi Ettore , Loeschcke Volker
Published: May 2003

Aim Local populations from different geographical regions may differ in the selection regimes to which they are exposed. Differences in environmental factors and population density may affect the relative importance of different selective forces (e.g. natural vs. sexual selection). We suggest a direction of investigation concerned with the developmental instability of morphological traits. The goal is to disclose putative small‐scale geographical differences in the evolutionary forces, which may be hard to detect.

Location Craniometrical investigations were carried out on ninety‐eight skulls and teeth of the Eurasian badger (Meles meles) collected during the period 1995–97 from three different populations in Denmark. One of these thrives at low population density, whereas the two others are characterized by high local density.

Methods The skulls were investigated for developmental instability (DI) using fluctuating asymmetry (FA) as its estimator. FA was measured on canines, molars, premolar teeth and other skull and mandible traits. For the statistical analyses, we applied nonparametric permutation tests.

Results Evidence was found suggesting differentiation among populations in mean degree of FA, and the FA values measured on canines were higher in the high‐density populations. FA of the canines was significantly higher in males than females, in contrast to FA of the other traits. Evidence of a negative relationship between canine size and their FA was found, whereas no significant correlations were found between the molar and premolar teeth measures and their FA.

Main conclusions Our results suggest that canines could be under directional selection stemming from intrasexual competition, which may be stronger in high‐density zones. The other teeth investigated seem to be under a stabilizing regime hence their FA is mainly affected by environmental stresses. The negative relationship between canine size and FA found in males suggests the capacity of badgers to respond in an evolutionary way to environmental changes, despite the low genetic variability previously found at the molecular level.
Island biogeography of temporary wetland carabid beetle communities
Authors: Brose Ulrich
Published: May 2003

Aim  The study tests if island biogeography is applicable to invertebrate communities of habitat islands in the agricultural landscape that are not fragments of formerly larger habitats.

Location  Thirty temporary wetlands in the agricultural landscape of northeast Germany.

Methods  The composition and species richness of carabid beetle communities was analysed. Habitat area, isolation, the density of temporary wetlands in the landscape, land‐use intensity and the maximum duration of flooding were recorded as independent variables. Overall species richness and wetland species richness were studied in independent regression analyses. The community composition was analysed by means of a Canonical Correspondence Analysis (CCA). A partial CCA was used to analyse the effect of the distance to the edge of the field after removing impacts of other independent variables.

Results  The area of the habitats and various measures of isolation (mean distances = 81–240 m) did not influence species richness or wetland species richness. The community composition was mainly determined by the land‐use intensity, habitat area did not have significant effects, and the distance to the edge of the field was the only effective isolation parameter. Short‐winged species were more often affected by the distance to the edge of the field than full‐winged species.

Main conclusion  There is evidence that the distances between the wetlands do not provide an effective barrier to the species dispersal and, therefore, metapopulation structures including subpopulations of multiple temporary wetlands might counteract local area effects on subpopulations. Short‐winged species, however, might be more affected by isolation than full‐winged species. As carabid beetle community structure in most early successional habitats is similar, these results may be representative of many agricultural landscape habitats. Nature conservancy concepts that aim to increase habitat area and habitat connectivity have successfully been applied to fragmented late‐successional habitats. The present study indicates that such concepts do not necessarily result in higher diversity or larger populations in early successional habitats.
The limits to biogeographical distributions: insights from the northward range extension of the marine snail, Kelletia kelletii (Forbes, 1852)
Authors: Zacherl Danielle , Gaines Steven D. , Lonhart Steve I.
Published: May 2003

Aim The development of accurate models predicting species range shifts in response to climate change requires studies on the population biology of species whose distributional limits are in the process of shifting. We examine the population biology of an example system using the recent northward range expansion of the marine neogastropod Kelletia kelletii (Forbes, 1852).

Location This is a marine coastal shelf neogastropod species whose range extends from Isla Asuncion (Baja California, Mexico) to Monterey (CA, USA). Research sites spanned the extent of the range.

Methods We examine abundance distributions and size frequency distributions of K. kelletii for evidence of factors determining historic and contemporary distributional patterns. Population studies were supplemented by historic and contemporary hydrographic data, including seawater temperature data from California Cooperative Oceanic Fisheries Investigations (CalCOFI ) and National Data Buoy Center (NDBC), and seawater circulation data.

Results The structure of recently established populations varied dramatically from that of historic populations. Markedly low densities and irregular size frequency distributions characterized recently established populations and suggested only occasionally successful recruitment. The point of transition between historic and recently established populations also corresponded to the location of a gradient in seawater temperature and the confluence of two major oceanic currents. The accumulated data suggest that temperature and/or barriers to dispersal could have set both contemporary patterns in population structure as well as the former northern range limit.

Main conclusions Early life stages play a critical role in determining distributional patterns of K. kelletii. Dispersal barriers and temperature limitation are two plausible mechanisms that could determine both contemporary and historic distributional patterns. Future studies on this species should attempt to tease apart the relative importance of these factors in maintaining the populations at the northern edge of the range.
Non‐linearity in clinical practice
Authors: Petros Peter
Published: June 2003

The whole spectrum of medicine consists of complex non‐linear systems that are balanced and interact with each other. How non‐linearity confers stability on a system and explains variation and uncertainty in clinical medicine is discussed. A major theme is that a small alteration in initial conditions may have a major effect on the end result. In the context of non‐linearity, it is argued that ‘evidence‐based medicine’ (EBM) as it exists today can only ever be relevant to a small fraction of the domain of medicine, that the ‘art of medicine’ consists of an intuitive ‘tuning in’ to these complex systems and as such is not so much an art as an expression of non‐linear science. The main cause of iatrogenic disease is interpreted as a failure to understand the complexity of the systems being treated. Case study examples are given and analysed in non‐linear terms. It is concluded that good medicine concerns individualized treatment of an individual patient whose body functions are governed by non‐linear processes. EBM as it exists today paints with a broad and limited brush, but it does promise a fresh new direction. In this context, we need to expand the spectrum of scientific medicine to include non‐linearity, and to look upon the ‘art of medicine’ as a historical (but unstated) legacy in this domain.
Achieving change in health care practice
Authors: Redfern Sally , Christian Sara
Published: June 2003

This study evaluated a practice development programme consisting of nine projects together known as STEP (South Thames Evidence‐Based Practice Project). The aim of STEP was to establish and assess evidence‐based practice in nursing and other health care practice areas. Objectives of the independent evaluation were to identify and assess outcomes from the process of change and investigate the association between these intermediate outcomes and patient outcomes. Outcomes were measured before and after the changes were introduced. Data collection methods included interviews with the change agents and other stakeholders, and a questionnaire to staff in each centre. Patient outcome data were collected from each centre. The findings revealed ‘dissemination’ of information to staff and ‘adherence’ by staff to new practice guidelines to be important intermediate outcomes in the process of change. The need emerged for a supportive organizational culture and commitment, recognition of the importance of change and a credible change agent. There was some evidence of linearity in the process of change in that a logical route appeared from dissemination of information to staff through adherence to the change guidelines to improvement in patient outcome in six of the nine centres. Linearity was less apparent in the other three centres, where the process of change seemed more dynamic and chaotic. These three centres were affected more than the others by organizational barriers to change. Our conclusions support the view that the linear model of change can work in settings with high levels of certainty but complexity theory is more likely to underpin the process of change in organizations characterized by uncertainty.
A critical appraisal of evidence‐based medicine: some ethical considerations
Authors: Gupta M.
Published: June 2003

Evidence‐based medicine (EBM) is a concept that has grown to dominate the medical literature over the last decade. EBM has provoked a variety of criticisms, scientific, philosophical and sociological. However, while its basic conclusion – that we should practise EBM – is ethical, there has been limited ethical analysis of EBM. This paper aims to provide an analysis of EBM from an ethical perspective and identify some of EBM's potential ethical implications. Following a description of what constitutes EBM, this paper will identify and assess some of the basic values and epistemological assumptions of EBM that provide support for the moral duty to practise EBM. It will then examine potential ethical implications that could arise from practising EBM, given the challenges that have been made of EBM's assumptions and claims to authority. This paper will conclude by arguing that practitioners could strengthen the ethics of EBM by embracing a broader definition of evidence and including ethical criteria in the critical appraisal of research studies.
Production and characterization of intergeneric somatic hybrids between Moricandia arvensis and Brassica oleracea
Authors: Ishikawa S. , Bang S. W. , Kaneko Y. , Matsuzawa Y. , Röbbelen G.
Published: June 2003

Somatic hybrids were produced between Moricandia arvensis (MaMa, 2n= 28) and Brassica oleracea (CC, 2n= 18) through cell fusion and then characterized by analysing their morphology, cytology, DNA constitution, leaf anatomy and seed fertility. Cell fusion was carried out between greenish protoplasts isolated from the mesophyll of M. arvensis and colourless ones from hypocotyls of B. oleracea. Three plants were generated from one shoot via cuttings and acclimatized in vivo. They closely resembled each other in morphology, exhibiting traits intermediate between the parental species. They were confirmed to be amphidiploids by mitotic and meiotic analyses, being 2n= 46 (MaMaCC), with pollen fertility of about 50%, which was enough to develop the subsequent progenies. Anatomical analysis of the for leaf tissue showed that the bundle sheath cells of the somatic hybrids contained some centripetally arranged organelles, like those of M. arvensis. The hybridity was also confirmed by random amplified polymorphic DNA analysis. Both chloroplast DNA and mitochondrial DNA of the somatic hybrids were estimated to be derived from M. arvensis. In leaf anatomy, the somatic hybrid showed the C3‐C4 intermediate trait as in M. arvensis. Many progenies resulted from backcrossing with parental species. The somatic hybrids are expected to be used as bridging plant material to introduce the C3‐C4 intermediate trait into Brassica crop species.
Genetic gains for yield after two back‐crosses of the interspecific hybrid Libusta (Coffea canephora P. × C. liberica Bull. Ex Hiern) to C. canephora P.
Authors: Yapo A. , Louarn J. , Montagnon C. , Weber W. E.
Published: June 2003

The Libusta (Coffea canephora P. × C. liberica B.) programme initiated in the seventies in Côte d'Ivoire aims at improving the quality of coffee grown in low altitudes, with a yield comparable to current commercial C. canephora clones. The second generation of back‐crosses to the C. canephora (CAN) parent, BC2, are now likely to be commercially exploited as far as yield is concerned. The best BC2 progeny yielded 1386 kg of green coffee/ha/y, averaged over five harvest years. On average, the genetic gain for yield from BC1 to BC2 reached 22%. In a factorial mating design, no interaction was observed between BC1 and CAN parents, while both main effects were highly significant. This explained that observed genetic gains and further genetic gains may be achieved with appropriate strategies.
Genetic stability and maintenance of Raphanus sativus lines with an added Brassica rapa chromosome
Authors: Kaneko Y. , Yano H. , Bang S. W. , Matsuzawa Y.
Published: June 2003

The genetic stability and maintenance of Raphanus sativus‐Brassica rapa monosomic chromosome addition lines (a‐h‐types MALs, 2n = 19, BC2), developed by backcrossing the synthesized amphidiploid Raphanobrassica (Raphanus sativus × Brassica rapa, 2n = 38, RRAA) with R. sativus cv. ‘Shogoin’ (2n = 18, RR), was investigated. Transmission of the added alien chromosome through selected smaller seeds (SSS) and the inheritance of morphological traits and random amplified polymorphic DNA (RAPD)‐specific markers together with meiotic chromosome configuration and seed fertility were also investigated for three successive generations (BC3 to BC5). The distinctive traits and the RAPD‐specific markers of the eight types of MAL were substantially inherited and stably maintained throughout three generations, although a few variant plants (2n =18) resembling MALs (2n = 19) and hyperploidal plants (2n = 26 and 2n = 37) were generated in the earlier generations of BC3 and BC4 in comparison with BC5. The average transmission rates for three generations ranged from 26% for both the b‐type and the d‐type to 44% for the e‐type through SSS. On the other hand, the transmission rates through randomly selected seeds (RSS) were lower, ranging from 6.5% for the f‐type to 23.5% for the b‐type. In meiosis, more than 90% of PMCs showed the 9II +1I pairing configuration at metaphase I throughout three generations. For seed fertility, when backcrossed with the radish cv. ‘Shogoin’, the values were approximately 180% to 500% with the mode around 300% with the seed harvested from a pod increasing with the advancing generations. Genetic recombination between the radish chromosomes and the added chromosome is probably rare, suggesting that the added chromosome is mostly maintained unaltered in the background of the radish genome.
Low relative humidity increases haploid production in durum wheat X maize crosses
Authors: Ballesteros J. , García‐Llamas C. , Ramírez M. C. , Martín A. , Weber W. E.
Published: June 2003

Haploidization is a useful tool for genetic analysis and plant breeding, but a consistent and satisfactory protocol for haploid production has been difficult to achieve in durum wheat. The objective of this study was to analyze the influence of the relative humidity of the environment, when culturing detached tillers during the production of haploids plants in durum wheat by the maize method. Thirty‐eight F3 lines from eight crosses of durum wheat were pollinated with bulked pollen from three commercial maize hybrids. A mixture of 2‐4D and dicamba was used as a hormone treatment. The numbers of caryopses, embryos and haploids plants were scored. When 65‐85% (light‐dark) humidity was substituted for 55‐65% the number of haploids per spike increased notably. This increased frequency was largely attributed to a rise in the production of generated caryopses. On average, 15.2 vs. 9.3 caryopses, 5.0 vs. 2.8 embryos, and 3.1 vs. 0.6 haploid plants, per spike, were produced under low and high humidity regimes, respectively.
Working in a community recreation program: A study of consumer‐staff perspectives
Authors: Yuen Maria S. K. , Fossey Ellie M.
Published: May 2003

Consumers working as service providers make unique contributions to the quality, accessibility, and responsiveness of mental health services. Relatively little research has explored these roles. This study used a naturalistic inquiry methodology to explore consumer‐staff views of working in a program that assists people living with mental illness to access recreation. Three consumer‐staff were interviewed about the rewards and challenges of their work. Qualitative analysis of participants’ views identified eight themes: (i) wanting purposeful activity; (ii) the importance of work; (iii) rewards of helping others; (iv) re‐establishing social networks; (v) gaining a sense of belonging; (vi) experiencing teamwork; (vii) challenges of working; and (viii) maintaining well‐being. These findings suggest consumer‐provider initiatives may create occupational opportunities and facilitate empowerment of consumers in provider roles. A team approach, clear roles, appropriate remuneration and support are central to achieving these benefits. Occupational therapists should advocate for, and support such initiatives that empower consumers in overcoming barriers to meaningful occupation.
Value of life stories in occupation‐based research
Authors: Wicks Alison , Whiteford Gail
Published: May 2003

Life stories are valuable resources in occupational therapy because they are personal interpretations of people's occupational participation throughout their life course. Life stories can be used as data in occupation‐based research to understand the form, function and meaning of occupation at different stages of a person's life. As occupational therapy aims to enable people to participate in meaningful occupation, understandings gained from life‐story analysis can be incorporated into the knowledge base of occupational therapy, to advance practice.
Occupational therapy intervention, involving preventive health promotion, maintained an improvement in well being in older independent‐living adults 6 months following completion of intervention
Authors: Wallen Margaret , Stanley Mandy
Published: May 2003

Introducing a new department in the Australian Occupational Therapy Journal: Critically Appraised Papers or CAPs. This department arose from a demand for critical appraisal of relevant research literature to keep occupational therapists up‐to‐date with advances related to practice. The broad aim is to publish two CAPs on a theme; one an RCT or systematic review, the other qualitative research. Each CAP will consist of a structured abstract of the content of the research and a commentary completed by an expert in the field. The commentary will critically appraise the research, place it in context with existing research and discuss practice implications.
Advances in bioherbicide formulation
Authors: AULD BRUCE A. , HETHERINGTON SHANE D. , SMITH HEATHER E.
Published: May 2003

Formulation of a bioherbicide ideally should result in a product that has low cost, long shelf‐life, ease of application and efficacy. Formulation persists as a constraint to commercial development of many potential bioherbicides often because dew dependence in fungi limits their efficacy under dry‐land conditions. This has not been a problem with several commercial bioherbicides because they are used in irrigated systems or applied as wound inoculations. Thus, reduction in dew dependence is a principal aim in the formulation of many potential bioherbicides. In the present paper, formulation research attempting in part to overcome this problem via the development of novel solid and liquid formulations is described. Solid formulations typically must be able to survive in the field and await suitable conditions before becoming activated. Liquid formulations have the potential to produce infections soon after application provided they remain moist on the target plant surface. Several attempts to improve water‐holding capacity in liquid formulations have been examined. The use of multiple emulsions of water in oil in water has recently shown promise.
Impact of direct dry seeding on rainfed paddy vegetation in north‐east Thailand
Authors: TOMITA SHINSUKE , NAWATA EIJI , KONO YASUYUKI , INAMURA TATSUYA , NAGATA YOSHIKATSU , NOICHANA CHAIRAT , SRIBUTTA AKKADET
Published: May 2003

In north‐east Thailand where rainfed paddy cultivation is commonplace, direct dry seeding is replacing transplanting to increase the frequency of successful plantings and to save labor. The present study shows the impact of this change on paddy vegetation from agricultural and ecological viewpoints. One hundred and seventy‐nine paddy fields from a wide range of climatic, topography, soil and hydrological conditions were used in this study. Authors visited these fields every 3 weeks during the rainy seasons of 1996–1998 to collect data about water conditions, rice growth, progress of cultivation, paddy vegetation and roughness (unevenness) of the soil surface. Analysis of this data revealed that direct dry seeded fields are resource‐poor and have a wider range of water conditions within a field than transplanted fields due to a rougher soil surface. This results in lower productivity of total vegetation for rice growing in direct dry seeded fields. However, weed productivity was not significantly different between the direct dry seeding and transplanted fields. Direct dry seeded fields have more species‐rich vegetation and greater diversity than the transplanted fields. Previous planting methods for particular fields did not influence productivity and diversity of paddy vegetation. It is concluded that the use of direct dry seeding increases biomass production of rice and the diversity of the paddy vegetation. The present results also suggest that an analytical framework be used to integrate agricultural and ecological studies of paddy vegetation in order to harmonize agricultural productivity with biological diversity.
Analysis of weed vegetation of no‐tillage upland fields based on the multiplied dominance ratio
Authors: KOBAYASHI HIROYUKI , NAKAMURA YOSHIO , WATANABE YOSHIAKI
Published: May 2003

The objective of the present study was to clarify the characteristics of weed vegetation in no‐tillage upland fields in Japan. Vegetation surveys were conducted in two stages and the obtained data were analyzed based on the multiplied dominance ratio. The first was a two‐year survey of a no‐tillage field and a tilled field where no‐tillage or tillage farming had been carried out for more than 10 years. The no‐tillage field surveyed exhibited a different seasonal succession from the tilled field. Summer annuals dominated the tilled field in summer, and winter annuals dominated in spring. Perennials occupied the no‐tillage field in spring; summer annuals also dominated in summer. The second survey was of 19 and 22 fields, including some no‐tillage fields, in the summer of 2000 and the spring of 2001. The vegetation in both summer and spring was classified into three vegetation types, principally dependent on the no‐tillage periods: types I and II consisted mainly of tilled and under 3‐year‐old no‐tillage fields, and type III comprised no‐tillage fields three years old or over. Type II vegetation was characterized primarily by the presence of biennials and perennials of Asteraceae, and type III by perennials, such as sweet vernalgrass (Anthoxanthum odoratum), in addition to the same species as type II. Summer annuals such as southern crabgrass (Digitaria ciliaris) were abundant in many fields in summer regardless of the vegetation types.
Approach of allelopathy study with Arabidopsis thaliana (L.) Hevnh. and Neurospora crassa
Authors: TOMITA‐YOKOTANI KAORI , KATO TAKAKO , PARVEZ MOHAMMAD MASUD , MORI YASUHEI , GOTO NOBUHARU , HASEGAWA KOJI
Published: May 2003

Allelopathy in Arabidopsis seeds was investigated in the present study because there are few available reports of allelopathy studies regarding the early development stage of the plant life cycle, and because Arabidopsis is widely used as a model plant for molecular biology. When cockscomb (Celosia cristata) was incubated together with Arabidopsis seeds, the growth of cockscomb was promoted by Arabidopsis seeds. Exudate of Arabidopsis seeds showed a promotive activity on the growth of cockscomb and Arabidopsis itself. A new method for studying allelopathic mechanisms involving the interaction of the plant Arabidopsis thaliana (L.) Hevnh. and the fungus Neurospora crassa was suggested. Arabidopsis seed exudate and the water‐soluble fraction of the exudate promoted Arabidopsis growth and reduced fungal germination, indicating that the seed exudate has a species‐selective activity. Conversely, the ethylacetate‐soluble fraction inhibited growth of all tested materials in the current study. These results demonstrate that the water‐soluble substance(s) released from Arabidopsis seeds have species‐selective activity on growth of both plants and microorganisms.
Physiochemical factors affecting the salt tolerance of Echinochloa crus‐galli Beauv. var. formosensis Ohwi
Authors: YAMAMOTO AKIHIRO , SHIM IE‐SUNG , FUJIHARA SHINSUKE , YONEYAMA TADAKATSU , USUI KENJI
Published: May 2003

The effects of NaCl‐induced stress on physiochemical factors such as inorganic cations, proline, malondialdehyde (MDA) and polyamines were investigated in the gramineous weed, Echinochloa crus‐galli Beauv. var. formosensis Ohwi (E. crus‐galli) and rice (Oryza sativa L. cv. Nipponbare). Growth inhibition at the 2nd leaf stage under salt stress was more severe in rice than in E. crus‐galli. Water content in the 2nd leaves was also more severely decreased in rice, indicating that E. crus‐galli was more salt‐tolerant. After NaCl treatment, Na+ accumulated in the 2nd leaves of both plant species but not in their roots. Proline accumulation in the 2nd leaves was significantly higher in salt stressed E. crus‐galli than in rice, suggesting the significance of proline production in the salt tolerance of this weed. Content of MDA of the rice increased more greatly with NaCl treatment than that in E. crus‐galli. NaCl treatment affected polyamine metabolism of both plant species, but the response of each plant to salt stress was somewhat different, especially in the leaves. Leaf putrescine and spermidine contents were high in non‐stressed plants in salt‐sensitive rice, although rather lower in E. crus‐galli in response to NaCl concentrations. These results indicate that an increase in proline and changes in polyamines relates to the salt tolerance of E. crus‐galli.
Spatial heterogeneity and diurnal course of photon flux density on paddy field water surface under rice plant canopy
Authors: NISHIMURA SEIICHI , ITOH KAZUYUKI
Published: May 2003

Detailed measurements of photon flux density (PFD) on the paddy field water surface were conducted under sunny sky conditions using a photosensor array of 100 small photodiodes under rice canopies at the heading and ripening stages. PFD on paddy water surface was not uniform and spatially variable even within a short distance of a few centimeters, showing that the irregular penetration of direct sunlight significantly affects the light environment under the canopies. Although occasional high peaks of PFD were observed, most of the water surface was exposed to a PFD of less than 200 µmol m−2 s−1, even around midday. Mean PFD were high at midday and low in early morning or late evening. Mean ratios of the PFD under the canopy to that outside the canopy (RPFD) were also high at midday and low in early morning or late evening, which can be explained by Poisson's model of light penetration. Maximum mean PFD and mean RPFD were often observed not around noon, but when the azimuth angle of the sun coincided with the row direction. Moreover, under rice canopies at the heading stage, rapid increases and decreases of mean RPFD were observed immediately before and after the peak time. These results indicate that significant high photosynthetic carbon fixation by the paddy field weeds can take place only during the few hours when the azimuth angle of the sun coincides with the row direction.
Allelopathy of pinecone in Japanese red pine tree (Pinus densiflora Sieb. et Zucc.)
Authors: NODE MARI , TOMITA‐YOKOTANI KAORI , SUZUKI TOSHISADA , KOSEMURA SEIJI , HIRATA HIROAKI , HIRATA KIMINORI , NAWAMAKI TSUTOMU , YAMAMURA SHOSUKE , HASEGAWA KOJI
Published: May 2003

There are fewer weeds in the ground covered with pinecones of Japanese red pine trees (Pinus densiflora Sieb. et Zucc.) than in the ground without pinecones. When six species of seeds were cultured with Japanese red pinecones on agar, the growth of cress, lettuce and cat's eye were inhibited. Pinecones had a plant species‐selective influence on their growth. Exudates of the pinecones showed high biological activity and also plant species‐selective activity. Some species‐selective allelopathic substances may be released from the pinecones. One of the inhibiting allelopathic substances was isolated from the exudates of the pinecones using a bioassay of cat's eye. The substance was identified as phenylacetic acid from an ESI‐MS and 1H NMR spectra. It inhibited shoot and radicle elongation of cat's eye at concentrations of 30–100 p.p.m. The substance was also isolated from an agar medium after removal of the pinecones. These results suggest that pinecones may inhibit some weeds that grow around pine trees. There are many reports of the allelopathic effect of leaves, bark and roots of many plants, however, this is the first report that reveals the cone also affects the allelopathy phenomenon in Japanese red pine trees.
Differences in weed vegetation in response to cultivating methods and water conditions in rainfed paddy fields in north‐east Thailand
Authors: TOMITA SHINSUKE , NAWATA EIJI , KONO YASUYUKI , NAGATA YOSHIKATSU , NOICHANA CHAIRAT , SRIBUTTA AKKADET , INAMURA TATSUYA
Published: May 2003

Rainfed paddy cultivation predominates in north‐east Thailand. Direct dry seeding is replacing transplanting rice cultivation to increase the frequency of successful plantings and to save labor. The present study clarified differences in weed vegetation of direct dry‐seeded and transplanted paddy fields under rich, medium and poor water conditions from agricultural and ecological viewpoints. A large number of paddy fields from a wide range of climatic, topographic, soil and hydrological conditions were used. A survey was conducted every three weeks, and data regarding paddy cultivation, weeds and water conditions were collected. Expansion of direct dry seeding may increase species with in‐between water adaptability to hygrophytes and mesophytes, and decrease hydrophytes and mesophytes. This characteristic was remarkable under poor water conditions. Rice cover was similar in either planting method under rich water conditions. However, cover of direct‐seeded rice was significantly smaller than that of transplanted rice under medium and poor water conditions. Species diversity was higher in direct dry‐seeded paddy fields than in transplanted paddy fields under medium and poor water conditions. Impact of direct dry seeding in the fields with rich water conditions on the vegetation is small in the context of maintaining rice production by transplanting and species diversity. However, direct dry seeding is mainly adopted in fields with poor water conditions. Impact of the changes in cultivating methods is large on rice productivity, species composition and species diversity under such conditions. Therefore, how to best use resource‐poor fields may be the key to maintaining rice production and regional‐level species diversity.