bluuebunny/crossref_metadata_2025 huggingface dataset:
Heart failure and its impact on older women's lives
Authors: Rhodes Diane L. , Bowles Cheryl L.
Published: March 2003

Aim of the study.  This phenomenological study sought to examine and describe the experience of living with heart failure (HF) from the perspective of five women who live with Stage II HF.

Background.  Research has shown that women are affected by HF differently than men, having different risk factors, a higher increase in mortality per decade, and longer survival after diagnosis. Women have also been greatly under‐represented in studies of HF. A search of the literature revealed only one Swedish study examining the overall impact of HF on women's conceptions of their own lives.

Research methods.  Four 1‐hour semi‐structured interviews were held with each participant. Colaizzi's steps were used to analyse the verbatim transcripts of the interviews, drawing meanings from the participants' words.

Findings.  Four main themes emerged from the data: ‘Acknowledging Losses in Their Lives’, ‘Accepting the Losses’, ‘Changing Their Lives’ and ‘Deepening Relationships’. Additionally, each theme contained several subthemes.

Conclusion.  Findings from this study indicate that no aspect of women's lives escapes the impact of HF. It causes immense losses in many areas of life, and requires tremendous changes in many aspects of daily living. Yet, drawing on inner resources of great strength and courage, these women learn to find contentment in their lives. They discover ways to create productive lives and deeply meaningful relationships, within the boundaries imposed by HF.
Dis/integrated care: family caregivers and in‐hospital respite care
Authors: Gilmour Jean A.
Published: March 2003

Aim.  The aim of this study was to explore family caregivers' experiences of in‐hospital respite care for people with dementia and the factors that influenced their perceptions of the service.

Background.  The provision of respite care is based on the assumption that temporary relief from caregiving will relieve caregiver stress and may possibly extend the duration of home care. Research evidence suggests that this is a simplistic perspective which fails to account for families' concerns about the quality of institutional care and the impact of relocation on the person being cared for.

Design.  Nine family caregivers, using four different hospitals sites were interviewed during a period of 3 years from 1994 to 1997. The research texts were analysed using a critical discourse analysis approach drawing on the work of Foucault.

Findings.  Family caregiver texts were distinguished by difference rather than by homogeneity. Caregivers occupied a range of positions in terms of their ability to take advantage of the respite time intermittent care offered. My reading of these texts has highlighted the aspects of nurse–family relationships that ameliorated, or alternately exacerbated, the tensions felt by caregivers, as they were torn between the necessity to have a break and their anxieties about the impact of in‐hospital respite care on the person with dementia.

Conclusion.  Nurses' practices in this study were a critical element in facilitating, or alternately constraining, family caregivers' ability to relinquish care and to take full advantage of the respite time. The research findings highlight the need for nurses and other formal caregivers to locate themselves in a secondary and supporting caregiving role, to acknowledge the family caregivers as the primary caregiver, and use family caregivers in‐depth and intimate knowledge of the needs of their relative to inform care within the institutional setting.
Titmuss and the gift relationship: altruism revisited
Authors: Rapport F.L. , Maggs C.J.
Published: March 2003

Rationale.  This paper revisits Richard Titmuss' 1970s blood donation model in the light of its 1997 reprint in order to consider whether we are justified in continuing to accept that the main reason for blood donation (and other donation types) is an altruistic desire to help others.

Aim.  This paper explores how others have examined the notion of altruism, before concentrating on two major elements of Titmuss' work: blood donors' motives to donate and the social implications of gift‐giving in relation to the uniqueness of blood donation.

Design.  Donor motivation is discussed in detail with particular reference to questions 4 and 5 of Titmuss' blood donor survey and through a critical appraisal approach to his work.

Findings.  Methodological inconsistencies are revealed in the design and implementation of the survey, as well as in Titmuss' list of blood donation's unique attributes, bringing into question the rigour of his findings. It may be that blood donors are altruistically motivated, but such conclusions cannot be drawn from this work. It is also unclear if ‘altruism’ can be shown in the example of blood donation or other donation types.

Recommendations.  We should reconsider the motivation behind gifting in health care in the light of these findings and ensure that evidence‐based practice is consistent with methodological rigour. Nurses and other health professionals need to have a clearer understanding of concepts such as altruism in order to appreciate why people seek to donate.
A review of physical restraint minimization in the acute and residential care settings
Authors: Evans David , Wood Jacquelin , Lambert Leonnie
Published: March 2003

Objectives.  The objective of this review was to investigate physical restraint minimization in acute and residential care settings. The first aim was to determine the effectiveness of attempts to minimize the use of physical restraint, and the second was to generate a description of the characteristics of restraint minimization programmes.

Method.  A comprehensive search was undertaken involving all major databases and the reference lists of all relevant papers. To be included in the review studies had to be an evaluation of restraint minimization in an acute or residential care setting. As only a single randomized controlled trial (RCT) was identified, it was not possible statistically to pool the findings of different studies on the effectiveness of restraint minimization. To generate a description of the characteristics of restraint minimization programmes, the reported components of these programmes were identified and categorized.

Results.  A total of 16 studies evaluating restraint minimization were identified: three in acute care and 13 in residential care. Of these, only one was an RCT, with the most common approach being the before and after study design. Based on the findings of the single RCT, education supported by expert consultation effectively reduced the use of restraint in residential care. There has been little evaluation of restraint minimization in acute care settings. The common approach to restraint minimization has involved a programme of multiple activities, with restraint education being the characteristic common to most programmes.

Discussion.  Evidence suggests that physical restraint can be safely reduced in residential care settings through a combination of education and expert clinical consultation. There is little information on restraint minimization in acute care settings. The major finding of this review is the need for further investigation into all aspects of restraint minimization.
Development and testing of the theory of collaborative decision‐making in nursing practice for triads
Authors: Dalton Joanne M.
Published: March 2003

Background.  Although nurses depend heavily on informal family caregivers to provide care to clients and to be involved in care planning and decision‐making, no nursing theories that include the client, the caregiver, and the nurse were available to guide collaborative care planning and decision‐making.

Aim.  The purpose of this paper is to describe the construction and initial testing of the theory of collaborative decision‐making in nursing practice for a triad. The theory represents an extension of Kim's theory of collaborative decision‐making in nursing practice. Kim's theory was developed to describe and explain collaborative decision‐making in a dyad (client and nurse). The inclusion of a third person (family caregiver) in the theory required the addition of concepts about the caregiver, coalition formation, and nurse and caregiver outcomes. The expansion of Kim's dyadic theory to a triadic theory was achieved by means of a modified version of the theory derivation process described by Walker and Avant.

Conclusions.  The theory of collaborative decision‐making in nursing practice for a triad can be used to guide further research and clinical practice. The theory provides a framework for researchers who are interested in studying the effects of collaboration regarding decision‐making among nurses, family caregivers, and clients. The initial testing of the new theory in home health care nursing revealed variety in the nature of the client–caregiver–nurse relationships, the many processes used by the nurses in proceeding with the home visits, a multitude of decisions considered and different collaborative, noncollaborative, and coalition–forming interactions. The limited evidence of the empirical adequacy of the theory precludes development of definitive guidelines for clinical practice at this time. More studies are required before clinical practice guidelines can be developed.
Who owns the child in hospital? A preliminary discussion
Authors: Shields Linda , Kristensson‐Hallström Inger , Kristjánsdóttir Gudrun , Hunter Judith
Published: March 2003

Aim.  To ‘own’ a person is considered an infringement of human rights, but we suggest that concepts of ownership influence interactions between parents and staff when a child is admitted to hospital. This paper aims to stimulate debate and contains an explanation of the exploration of the literature for research and discussion of ownership of the child.

Method.  A wide variety of library indexes, databases and populist media were examined although it was impossible to examine all literature which may have contained references to this topic, and, apart from databases which contained abstracts in English, we could not include literature written in any language other than English, Swedish, and Icelandic.

Findings.  We found no research that examines how concepts of ownership of a child affects communication between health professionals and parents and, ultimately, the delivery of health care. This paper begins discussion on the issues.

Discussion.  Historical literature shows that ownership of humans has been a part of many cultures, and parents were once considered to own their children. Ownership of another has legal connotations, for instance in guardianship struggles of children during marriage breakup and in ethical debates over surrogacy and products of assisted conception. Within health care, it becomes a contentious issue in transplantation of body parts, in discourse on autonomy and informed consent, and for religious groups who refuse blood transfusions. In health care, models such as family centred care and partnership in care depend on positive communication between parents and staff. If a hospital staff member feels that he/she owns a child for whom he/she is caring, then conflict between the staff member and the parents over who has the ‘best interests of the child’ at heart is possible.

Conclusion.  We encourage debate about concepts of who owns the hospitalized child – the parents or the staff? Should it be argued at all? Is the whole concept of ownership of another, be it adult or child, the ethical antithesis to modern beliefs about human rights? Comment on this issue is invited.
Strategies for resolving aboriginal adolescent pregnancy in eastern Taiwan
Authors: Tsai Yun‐Fang , Wong Thomas K.S.
Published: March 2003

Background. Adolescent pregnancy has become a main issue in the health care system for aborigines in eastern Taiwan. Using aboriginal nurses to provide information on sexual behaviour may have potential as a means of promoting healthy sexual practices among aborigines.

Aim. To explore aboriginal nurses' perspectives on strategies for resolving the high prevalence rate of Aboriginal adolescent motherhood in eastern Taiwan.

Design and methods. A qualitative research design was employed and intensive individual interviews and focus groups were conducted among a convenience sample of aboriginal nursing staff in eastern Taiwan. Content analysis was used to analyse the data.

Results. Nine strategies were identified. They can be divided into family, school and society aspects. The family aspect included ‘enhancing parents’ sex education' and ‘enhancing the understanding of older people about sex education in villages’. The school aspect included ‘enhancing sex education in school’, ‘offering interrelationship courses for adolescents’, ‘offering gender issue courses for adolescents’ and ‘enhancing school teachers’ sex education training'. The social aspect included ‘advocating the sense of family in church’, ‘advocating social norms in church’ and ‘discussing appropriate sexual behaviour in adolescent church fellowships’.

Conclusions. Health care providers can design intervention programmes to reinforce the ability of family, school and society to deliver sex education. In addition, training and cooperating with Aboriginal nurses to execute these programmes may also decrease teenage pregnancy rates in the future.
Multi‐species territoriality and dynamic of neotropical forest understorey bird flocks
Authors: Jullien Mathilde , Thiollay Jean‐Marc
Published: March 2003

1.  Eleven contiguous mixed‐species bird flocks, with colour‐banded individuals, were monitored continuously during 3  years in a 132‐ha study area of primary rainforest in French Guiana.

2.  Flock members were divided into six categories according to their flocking propensity and occurrence: 10 core or permanent species and 56 regular, occasional or incidental species. Each core species was represented by a single breeding pair with their fledglings and extra ‘floaters’ (unmated subadults and adults).

3.  Flock home ranges overlapped slightly, but were communally defended by all core species in areas of overlap. Their size varied from 3·2 to 14·3  ha and was inversely correlated with vegetation density, but not flock size or species composition.

4.  Flock number, size and composition, as well as boundaries were highly stable between seasons and years. Each flock had a single permanent gathering site and bathing site in late afternoon, the latter sometimes shared by 2–3 flocks.

5.  Core species produced 0·18–0·73 fledglings per pair per year, which stayed in their natal flock for 200 to over 421 days. Then, these individuals usually moved between two and six different flocks, sometimes for up to 3  years, before finding a mate and a flock where they could settle and breed. Once breeding, they probably remained for life in the same flock. The mean annual survival rate was at least 0·75.

6.  This highly evolved and stable organization, associated with a low breeding success and high survival rate was a critical factor maintaining low species density, delayed reproduction and a proportion of floating individuals buffering population fluctuations.

7.  These social groups with their multi‐species territoriality and co‐evolved roles of flock members were similar to those described elsewhere in South America. They seem to be a general phenomenon in neotropical lowland rainforests.
Persistence thresholds for phocine distemper virus infection in harbour seal Phoca vitulina metapopulations
Authors: Swinton  , Harwood  , Grenfell  , Gilligan
Published: March 2003

1.  This paper explores the concept of the critical community size for persistence of infection in wildlife populations. We use as a case study the 1988 epidemic of phocine distemper virus in the North Sea population of harbour seals, Phoca vitulina.

2.  We summarize the available data on this epidemic and use it to parameterize a stochastic compartmental model for an infection spreading through a spatial array of patches coupled by nearest‐neighbour mixing, with replacement of susceptibles occurring as a discrete annual event.

3.  A combination of analytical and simulation techniques is used to show that the high levels of transmission between different seal subpopulations, combined with the small annual birth cohort, act to make persistence of infection impossible in this harbour seal population at realistic population levels. The well known mechanisms by which metapopulation structures may act to promote persistence can be seen to have an effect only at weaker levels of spatial coupling, and higher levels of host recruitment, than those empirically observed.
Mechanisms determining the spatial distribution of microtine predators on the Arctic tundra
Authors: Wiklund Christer G. , Kjellén Nils , Isakson Erik
Published: March 2003

1.  We studied the spatial distribution of avian microtine predators using data from 19 study areas on the tundra of northern Siberia.

2.  Numbers of snowy owls, and long‐tailed skuas and pomarine skuas depended strongly on lemming density. However, a significant relationship between lemming density and number of rough‐legged buzzards appeared first after removal of the effect of snowy owl abundance on the distribution of rough‐legged buzzards.

3.  We applied a recently developed method (Manly 1995) to examine co‐occurrences of species and found that rough‐legged buzzards and snowy owls did not co‐occur while snowy owls, long‐tailed skuas and pomarine skuas did.

4.  There are large differences in nest construction and chick behaviour between rough‐legged buzzards and the three other species. Moreover, the snow owl is a polyphagous predator preying also on large birds including raptor chicks. Therefore, we propose that reduced risk of nest predation favours rough‐legged buzzards nesting away from snowy owls.

5.  Variations in abundance of the two lemming species did not seem to influence the distributions of snowy owls and rough‐legged buzzards. Neither was it likely that latitudinally related factors such as breeding season length affected the distribution of rough‐legged buzzards.
Measuring the degree of sexual segregation in group‐living animals
Authors: Conradt Larissa
Published: March 2003

1.  So far, no measure exists to quantify sexual segregation in animal populations. Studies on segregation have relied on ecological measures of overlap and association to estimate the degree of segregation.

2.  However, existing ecological measures of overlap and association are stochastically related to sex ratio, population density or group size. These stochastic relations can lead to confounding results, making the existing measures unsuitable for quantitative studies on segregation.

3.  In the present paper a new measure of segregation, the ‘segregation coefficient’, is suggested, which is free of stochastic relations.

4.  The segregation coefficient is suitable for quantitative studies on segregation. It also makes possible, for the first time, comparisons between the degree of social segregation and the degree of habitat or spatial segregation in a population of animals.
A dynamic refuge model and population regulation by insect parasitoids
Authors: Lynch Liam D. , Bowers Roger G. , Begon Michael , Thompson David J.
Published: March 2003

1.  The population dynamic effects of refuges, which hosts enter and leave by diffusive movement, in host–parasitoid interactions are explored using simple models in continuous time.

2.  This type of refuge has a stabilizing effect on a host–parasitoid interaction, which is contrary to the implications of some previous models.

3.  Stability can be explained by considering how depletion processes lead to a refuge proportion (proportion of hosts protected at a given instant) that increases as parasitoid density increases. This effect is synonymous with pseudointerference in the context of the model.

4.  Very high rates of movement of host larvae largely destroy this stability process. Stability is greatest at intermediate levels of movement.

5.  Density‐dependent host movement can alter the effect of these refuges such that they are either more stabilizing, or tend to destabilize, the dynamics of host–parasitoid systems, depending on the type of density dependence assumed. The conclusion that intermediate movement rates are likely to generate stability with this general type of refuge is not altered in the presence of any type of density dependence, unless the density dependence is at levels which we consider unrealistically high and unlikely to be encountered in nature.

6.  It is the assumption that larvae do not move into the refuge prior to becoming vulnerable to parasitism that ensures top‐down population control in the model. Thus, parasitoids attacking very early instars make good candidates for biological control when faced with a structural refuge.
Hatching asynchrony in Eurasian kestrels in relation to the abundance and predictability of cyclic prey
Authors: WIEBE KAREN L. , KORPIMÄKI ERKKI , WIEHN JÜRGEN
Published: March 2003

Many hypotheses for hatching asynchrony within avian clutches centre around food supply during the laying or nestling periods, but food is measured in few studies.

Patterns of clutch size and hatching asynchrony were analysed in the Eurasian kestrel [Falco tinnunculus (Linnaeus)] breeding in Finland, where small mammal populations show dramatic 3‐year cycles.

Data collected over 12 years showed that clutches were larger when food was more abundant in spring.

While controlling for clutch size, hatching was more synchronous in the low phase of the vole cycle compared to the increase phase, contrary to conventional interpretation of the brood reduction hypothesis. The age of the female, but not the age of the male was associated with the degree of asynchrony.

Paradoxically, numbers of voles were most stable in the ‘low’ phase, which may lead to a unique situation, where food is more predictable when scarce. Kestrels have small, synchronous clutches in the ‘low’ phase and large asynchronous clutches in the ‘increase’ phase.

Based on results of this study, it is suggested that it is important to consider the predictability of food, and not only the mean abundance of food when evaluating hypotheses for hatching asynchrony. Patterns of clutch size and hatching asynchrony at the population level can be used to evaluate current energy‐related hypotheses for asynchrony.
Pre‐breeding survival of barnacle geese Branta leucopsis in relation to fledgling characteristics
Authors: JEUGD HENK P. VAN DER , LARSSON KJELL
Published: March 2003

Pre‐breeding survival, i.e. survival from fledging up to the third winter, of barnacle geese (Branta leucopsis) was analysed by using more than 45000 resightings of 1302 individually marked birds. Since observations from the wintering areas only were used, the survival estimates obtained were not confounded by natal dispersal.

Post‐fledging survival, i.e. survival from fledging to the start of the first winter, differed significantly among the 10 cohorts analysed. These differences were related to the mean body weight and mean tarsus length of cohorts just before fledging. In further analyses, when data from all cohorts were combined, body weight and tarsus length of individuals just before fledging were found to be positively related to Post‐fledging survival.

Post‐fledging survival rates were, on average, lower than survival rates after the first winter. This age effect was largest in cohorts with low mean body weight at capture and was absent in cohorts with high mean body weight at capture.

The age effect on survival could only partly be explained by individuals with low body weight having lower survival and successively disappearing from the cohort. It was therefore concluded that other factors must have contributed to the age effect as well.

It is hypothesized that lightweight birds are more vulnerable to, for example, diseases, parasites and predation during the first months of their life. Once they have survived this critical period, the effects of characters related to low body weight at capture seem to disappear.

Body size of juveniles just before fledging has previously been found to be greatly affected by weather factors and the availability of high quality food during the growth period. Hence, a considerable part of the observed variation in Pre‐breeding survival appears to be outside the individual's control.
Co‐existence between Iberian lynx and Egyptian mongooses: estimating interaction strength by structural equation modelling and testing by an observational study
Authors: PALOMARES F. , FERRERAS P. , TRAVAINI A. , DELIBES M.
Published: March 2003

We used path analysis to investigate the causal relationships between Iberian lynx and Egyptian mongoose track numbers, and to estimate the direct effect of the former on the latter in the Doñana area (2750 km2), south‐western Spain. Relative abundance of rabbits, shrub cover and protection level were also considered in the path analysis.

An observational study consisting of a repeated track survey with a split‐plot design was also carried out between 1990 and 1996 to independently test the results obtained by path analysis.

Maximum likelihood ratio tests of the goodness‐of‐fit of the model to the data and other indices used all indicated that the proposed theoretical model depicting the relationships among variables was adequate. Egyptian mongooses suffered a significant direct negative effect from lynx, and rabbits and protection level positively, and significantly affected lynx track abundance; rabbits were also significantly affected by shrub cover (all these standardized partial correlation coefficients ranged from 0.34 to 0.41). Shrub cover did not directly affect either lynx or mongoose tracks.

Relatively important indirect effects were found between shrubs and lynx (0.12), and between rabbits and mongooses (−0.14), and protection and mongooses (−0.17). The two latter non‐intuitive indirect effects were through the lynx path, as a consequence of the negative direct influence of lynx on mongooses.

The repeated track censuses confirmed that lynx presence significantly affects number of mongoose tracks. In areas without lynx, mean number of mongoose tracks were 3.6 times higher than in areas with lynx.

It remains an interesting question which of several proposed hypotheses explains co‐existence of both species in south‐western Spain.
Allometry of territory size and metabolic rate as predictors of self‐thinning in young‐of‐the‐year Atlantic salmon
Authors: Steingrímsson Stefán Ó. , Grant James W. A.
Published: March 2003

1. Self‐thinning is a progressive decline in population density caused by competitively induced losses in a cohort of growing individuals and can be depicted as: log10 (density) = c − β log10 (body mass).

2. In mobile animals, two mechanisms for self‐thinning have been proposed: (i) the space hypothesis predicts that maximum population density for a given body size is the inverse of territory size, and hence, the self‐thinning slope is the negative of the slope of the allometric territory‐size relationship; (ii) the energetic equivalence hypothesis predicts that the self‐thinning slope is the negative of the slope of the allometric metabolic rate relationship, assuming a constant supply of energy for the cohort.

3. Both hypotheses were tested by monitoring body size, population density, food availability and habitat for young‐of‐the‐year Atlantic salmon (Salmo salar) in Catamaran Brook, New Brunswick. The results were consistent with the predictions of the space hypothesis. Observed densities did not exceed the maximum densities predicted and the observed self‐thinning slope of −1·16 was not significantly different from the slope of −1·12, predicted by the allometry of territory size for the population under study.

4. The observed self‐thinning slope was significantly steeper than −0·87, predicted by the allometry of metabolic rate, perhaps because of a gradual decline in food abundance over the study period. The decline in density was more rapid in very shallow sites and may have been partly caused by a seasonal change in water depth and an ontogenetic habitat shift rather than solely by competition for food or space.

5. The allometry of territory size may be a useful predictor of self‐thinning in populations of mobile animals competing for food and space.
Egg viability as a constraint on hatching synchrony at high ambient temperatures
Authors: Stoleson Scott H. , Beissinger Steven R.
Published: March 2003

1. We tested experimentally the effects of exposure to high ambient temperatures, for periods of 1–9 days, on the viability of eggs of the green‐rumped parrotlet.

2. The hatchability of 534 newly laid parrotlet eggs declined after exposure of 3 or more days.

3. The probability of hatching was not significantly affected by the duration or proportion of time exposed to temperatures below physiological zero or above normal incubation range.

4. Incubation periods were negatively correlated with exposure time, suggesting some embryo development occurred prior to incubation.

5. Results presented here corroborate similar studies of temperate zone birds, and suggest that the decline in egg viability may be particularly extreme in hot climates, such as tropical lowlands.

6. We suggest that the relationship between ambient temperature and egg viability could contribute to both seasonal and latitudinal trends in clutch size, hatching success and hatching asynchrony.
Sex difference in criteria determining fidelity towards breeding sites in the great cormorant
Authors: Schjørring Solveig , Gregersen Jens , Bregnballe Thomas
Published: March 2003

1. Many animals choose to breed in sites where they have previously been successful. Such fidelity could arise from the predictability of high quality breeding sites in a temporally stable environment. The quality of a site may be indicated by factors other than an individual’s own success, because it may fail as a result of a random event that is unrelated to the intrinsic quality of the site. In particular, prior experience (familiarity) with the breeding area and the performance of neighbours could give complementary information about the quality of the site.

2. We present results from a long‐term study of colonial great cormorants (Phalacrocorax carbo sinensis), where movement and reproductive success of individually marked birds within a colony was known.

3. Individuals were more likely to return to the same breeding site if they had been successful the previous season.

4. Fidelity of both males and females increased with increasing level of familiarity with the breeding area. Males were more likely to breed again in the same area, and their fidelity was more dependent on familiarity with the area than female fidelity.

5. The success of breeding sites within the colony was spatially autocorrelated, and cueing on neighbour performance should thus be advantageous. Female fidelity increased with increasing success of neighbouring birds, while male fidelity was unaffected by neighbour success.

6. We suggest that the difference between the sexes in the criteria determining fidelity arises because it is mainly the males that are involved in territorial disputes. They may therefore benefit more than females from knowing their neighbours, and this could override the importance of the intrinsic quality of the breeding area (i.e. reproductive success of neighbours).

7. The conflict over preferred breeding sites that arises within breeding pairs because of this sex difference may be an explanation for the high rate of mate change between years (92.5%) observed in this species.
Beetles in fragmented woodlands: a formal framework for dynamics of movement in ecological landscapes
Authors: Murrell David J. , Law Richard
Published: March 2003

1. We consider the movement of carabid beetles in a fragmented woodland landscape. Landscape ecology has lacked a formal framework for the analysis of dynamics of this kind, and stochastic spatial simulations have generally been needed to gain insight.

2. We first define an individual‐based stochastic model for movement in a heterogeneous landscape. From this a deterministic approximation is derived which describes the build‐up in association of the beetles with their environment; the deterministic model makes use of a second‐order spatial moment. It is shown that the results of the deterministic approximation match closely those of the underlying stochastic process. On this basis we suggest that the dynamical system provides a formal framework for the dynamics of animal movements in ecological landscapes.

3. The results show that the beetles, starting from an initial random layout, rapidly become associated with the woodlands and, by the time 100 days have elapsed, the association is close to its asymptotic state. The strength of the association depends very much on the spatial auto‐covariance function of the environment.

4. A number of extensions are suggested, including landscapes comprising multiple habitats of different degrees of suitability, landscapes that change through human activity, birth and death processes of single species, and interactions between species. The method of moments provides a flexible basis for future work in this area.
Cycles and synchrony: two historical ‘experiments’ and one experience
Authors: Bjørnstad Ottar N.
Published: March 2003

1. Theoretical models predict that spatial synchrony should be enhanced in cyclic populations due to nonlinear phase‐locking.

2. This is supported by Rohani et al.′s (1999) comparison of spatial synchrony of epidemics in two childhood diseases prior to and during the vaccination era. Measles is both more synchronous and more cyclic before vaccination. Whooping cough, in contrast, is more synchronous during the vaccination era, during which multiannual fluctuations are also more conspicuous.

3. Steen et al. (1990) analysed historic records of cyclic rodents, to show that cyclicity was lost during the early part of the 20th century. I reanalyse the data, and find that the loss of cyclicity is associated with loss of regional synchrony.

4. I use a coupled map lattice model to show that imperfect phase‐locking provides an alternative explanation for regionwide synchrony of cyclic populations.
Mate fidelity, senescence in breeding performance and reproductive trade‐offs in the barn swallow
Authors: Saino Nicola , Ambrosini Roberto , Martinelli Roberta , Møller Anders Pape
Published: March 2003

Senescence is defined as the decline in performance with age, and can be determined by diverse mechanisms such as accumulation of mutations, ‘wear and tear’ and antagonistic pleiotropy. Animals can mitigate the negative effects of senescence on reproductive performance by acquiring experience as they age.

We analysed the effect of age on clutch size, breeding date, fledging success and offspring quality (morphology and T cell‐mediated immunity) of barn swallows (Hirundo rustica, Linnaeus) by comparing the progeny of individuals of known age during consecutive years.

Reproductive performance had no significant effect on probability of divorce, and adults that re‐mated with each other had no reproductive advantage.

Body size, feather development and T cell‐mediated immunity declined with paternal and/or maternal age already after the first breeding season. Body mass declined after paternal age of two years. T cell‐mediated immunity of nestlings in one year covaried negatively with that of their siblings the previous year.

Hence, barn swallows suffer an age‐dependent decline in offspring quality, and apparently trade quality of current offspring against that of subsequent reproductive events, although causality of this relationship could not be assessed in this correlational study.
Effects of fat reserves on annual apparent survival of blackbirds Turdus merula
Authors: Miller Mark W. , Aradis Arianna , Landucci Giuseppe
Published: March 2003

Fat reserves are stored energy that may help birds survive periods of harsh winter weather. This hypothesis predicts that annual apparent survival is higher for birds with large fat reserves than for birds with few or no fat reserves in winter.

Blackbirds (Turdus merula Linnaeus) were ringed in central Italy from 16 November to 20 February during 1990–2001. Fat scores were recorded for each bird. We used these capture–mark–recapture data for 1703 blackbirds to estimate the effect of large fat reserves on annual apparent survival, while controlling for transients, using computer programs surviv and mark. Probability of birds retaining large fat reserves, or retaining few fat reserves, over 2 successive years was also estimated.

Birds with large fat reserves did not have higher estimated annual apparent survival than birds with few fat reserves (φ̂large= φ̂few= 0·595, SE = 0·043), inconsistent with our prediction. No effects of age, sex or year were detected on annual apparent survival. Birds with few fat reserves in any given year tended to have few fat reserves the following year (, SE = 0·052). Birds with large fat reserves in any given year were unlikely to have large fat reserves the next year (, SE = 0·080).

Large fat reserves may not increase annual survival of blackbirds wintering in central Italy. Winter weather in our study area may be too mild to effect survival. Alternatively, increased predation risk associated with large fat reserves may counteract any benefits of reduced starvation risk.
The geographical range structure of the holly leaf‐miner. II. Demographic rates
Authors: Brewer Andrew M. , Gaston Kevin J.
Published: March 2003

Few studies have sought to document the variation in demographic rates exhibited by local populations across the geographical range of a species. None the less, such information has the potential to yield insights into the factors that determine the internal abundance structure of ranges.

Major components of demographic rates are reported here for the holly leaf‐miner Phytomyza ilicis Curtis across its natural geographical range in Europe, including areas at each of the extreme limits and at the core of its occurrence.

Correlograms reveal that a number of these components exhibit significant spatial structure across the geographical range and, in conjunction with interpolated maps, suggest that some of these patterns are, in terms of broad trends, reasonably simple.

Across the whole range, individual mortality components are largely independent of one another and of leaf‐miner population densities, often exhibiting very different spatial patterns. Thus, P. ilicis populations experience markedly different mortality profiles across the range.

While some correlations between broad‐scale environmental variation and the components of demographic rates were found, it was not possible to separate these effects from shared spatial structure.

In sum, the contribution of different components of demographic rates to local densities varies markedly across the geographical range of P. ilicis, and in isolation the pattern observed in any one locality provides limited information on what is occurring elsewhere, but these components none the less often exhibit systematic geographical patterns of variation.
Determinants of survival for the northern brown bandicoot under a landscape‐scale fire experiment
Authors: Pardon L. Guy , Brook Barry W. , Griffiths Anthony D. , Braithwaite Richard W.
Published: March 2003

More than half of all Australian bandicoot species (family Peramelidae) are listed by the IUCN as extinct or threatened and changed fire regimes in arid and semi‐arid Australia have been identified as an important agent in their decline. The northern brown bandicoot is currently one of Australia's most common bandicoots, but their continued persistence in the tropical savannas cannot be taken for granted. Previous studies in Kakadu National Park, Northern Territory have shown this species to be prone to sudden declines in abundance, possibly linked to the occurrence of intense fires.

Here we examine the impact of four experimental fire management regimes (fire prevention, early dry season burning, late dry season burning and progressive burning several times through the dry season) on survival of the northern brown bandicoot. The analysis is based on capture–mark–recapture data obtained during a landscape‐scale fire experiment conducted at Kapalga, in Kakadu National Park from 1989 to 1995.

All experimental fire treatments (including total fire exclusion) were associated with decline in survival rates over time, indicating that none of the tested approaches were appropriate for this species. Burning in the late dry season or progressively throughout the dry season produced substantially more severe declines in survival than did early dry season fires or fire exclusion.

Fire regime was found to be the most important determinant of bandicoot survival, far exceeding other factors such as gender, age, vegetation type, rainfall and season, all of which had comparatively little influence. The results demonstrate the importance of the frequency and seasonal timing of fires in determining the survival of bandicoots and suggest that spatially uniform and temporally invariant fire regimes are inappropriate for bandicoot conservation in the north Australian savannas.
Responses of Salsola kali and Panicum virgatum to mycorrhizal fungi, phosphorus and soil organic matter: implications for reclamation
Authors: Johnson N.C.
Published: March 2003

1.  Owing to the difficulty of finding terrestrial ecosystems without mycorrhizas, their influence on plant community dynamics is not easy to discern. This study utilized unreclaimed taconite mine tailings as a mycorrhiza‐free ecosystem to gain insights about the influence of arbuscular mycorrhizas and soil organic matter on the growth of Salsola kali (an early successional colonist of taconite tailings) and Panicum virgatum (a late successional grass planted during reclamation).

2.  To assess relative mycorrhizal responsiveness, Panicum and Salsola were grown in taconite tailings along an experimental phosphorus gradient with and without mycorrhizal fungal inoculum isolated from reclaimed taconite tailings. At low phosphorus concentrations, mycorrhizal inoculum enhanced the growth (height and dry mass) of Panicum, but it decreased growth at the two highest phosphorous concentrations. At no phosphorus level did mycorrhizal inoculum enhance the growth of Salsola but it decreased growth at the highest phosphorus concentrations.

3.  In field plots, mycorrhizal inoculum and organic soil amendment (compostedpapermill sludge) enhanced the growth of Panicum and decreased the growth of Salsola.

4.  In this experiment, mycorrhizal inoculum enhanced the growth of the late successional grass but, during reclamation operations, manipulating edaphic conditions to favour mycotrophy may be more cost‐effective than large‐scale inoculation. The results of this study suggest that mycotrophy is favoured by increasing soil organic matter and avoiding heavy fertilization.
Germination and emergence characteristics of triazine‐susceptible and triazine‐resistant biotypes of Solanum nigrum
Authors: Kremer E. , Lotz L.A.P.
Published: March 2003

1.  Seedling emergence patterns of triazine‐susceptible and triazine‐resistant Solanum nigrum in the field were studied in Wageningen, the Netherlands. Emergence patterns were similar in the first year, but in the second year resistant seedlings emerged faster and the number of resistant seedlings was higher. To explain emergence patterns, a germination experiment was carried out.

2.  Seeds from two populations with triazine‐susceptible and ‐resistant biotypes were buried in late autumn and exhumed monthly during spring. Germination was assessed in incubators at different constant temperatures.

3.  The lowest temperatures for germination of seeds from the Achterberg population ranged from 20°C on 1 February to 10°C on 1 May for the susceptible biotype, and from 15°C on 1 February to 10°C on 1 May for the resistant biotype. The lowest temperatures for germination of seeds from the Zelhem population ranged from 25°C on 1 February to 10°C on 1 May for the susceptible biotype, and from 15°C on 1 February to 10°C on 1 May for the resistant biotype. The minimum germination temperature of seeds from the resistant biotype appeared to be lower than that of the susceptible biotype.

4.  Emergence patterns in the field could be explained by soil temperature and different minimum germination temperature requirements of seeds from the triazine‐susceptible and ‐resistant biotype. This knowledge can be used to manage triazine‐resistant biotypes of S. nigrum by the timing of soil cultivation.
Environmental impact prediction using neural network modelling. An example in wildlife damage
Authors: Spitz François , Lek Sovan
Published: March 2003

1. Decision making in management of environmental impact confronts the problem of analysing relationships in highly complex ecological systems. These relationships are generally non‐linear, and conventional techniques do not apply satisfactorily. The problem is equivalent to that of predicting the output of a black box. Artificial neural networks (ANN) have shown tremendous promise in modelling such situations.

2. The present work describes the development and validation of an ANN in modelling wildlife damage to farmland, a particular instance of ecological impact. An ANN approach was developed and tested using data from 200 damaged plots, and a control sample of 20 undamaged plots, described by 17 environmental characters. The dependent variable was the financial cost of impact per plot.

3. The predictive quality of the ANN models was evaluated through the ‘leave‐one‐out’ procedure. For 82% of predicted values, deviation from observed values is lower than 1780, that is 10% of the range of the observed values. The frequency of bad predictions depends on the minimum level of impact (critical effect size) considered. In France, compensation is given starting from a minimum level of 200 FF. At this level, the frequency of occurrence of Type I errors (predicted impact does not occur) is 7·11%. Different strategies of prevention of impact, using different threshold values for prevention, are analysed. Frequency of Type I errors increases, and that of Type II errors (occurrence of unpredicted impact) decreases as the threshold for prevention increases.

4. Sensitivity analysis allows the determination of the effect of seven quantitative variables on the cost of damage compensation. Proximity of a paved road, proximity and number of houses, and number of other buildings contribute negatively, and three other variables (proportion of the perimeter of the plot occupied by woody vegetation, density of the vegetation, and density of wild boar in the surrounding area) contribute positively to the predicted value.

5. Results show that the utility of impact prediction for prevention depends on the cost of errors and the absolute cost of prevention.

6. Finally, ANNs proved able to learn complex relationships between environmental variables and impact assessment, and to produce operationally relevant predictions. Good predictions can help managers to distribute efficiently their actions between prevention, protection and compensation.