Flowering ecology of a Box-Ironbark Eucalyptus community

Box-Ironbark forests occur on the inland hills of the Great Dividing Range in Australia, from western Victoria to southern Queensland. These dry, open forests are characteristically dominated by Eucalyptus species such as Red Ironbark E. tricarpa, Mugga Ironbark E. sideroxylon and Grey Box E. microcarpa. Within these forests, several Eucalyptus species are a major source of nectar for the blossom-feeding birds and marsupials that form a distinctive component of the fauna. In Victoria, approximately 83% of the original pre - European forests of the Box-Ironbark region have been cleared, and the remaining fragmented forests have been heavily exploited for gold and timber. This exploitation has lead to a change in the structure of these forests, from one dominated by large 80-100 cm diameter, widely -spaced trees to mostly small (≥40 cm DBH), more densely - spaced trees. This thesis examines the flowering ecology of seven Eucalyptus species within a Box-Ironbark community. These species are characteristic of Victorian Box-Ironbark forests; River Red Gum E. camaldulensis, Yellow Gum E. leucoxylon, Red Stringybark E. macrorhyncha, Yellow Box E. melliodora, Grey Box E. microcarpa, Red Box E. polyanthemos and Red Ironbark E. tricarpa. Specifically, the topics examined in this thesis are: (1) the floral character traits of species, and the extent to which these traits can be associated with syndromes of bird or insect pollination; (2) the timing, frequency, duration, intensity, and synchrony of flowering of populations and individual trees; (3) the factors that may explain variation in flowering patterns of individual trees through examination of the relationships between flowering and tree-specific factors of individually marked trees; (4) the influence of tree size on the flowering patterns of individually marked trees, and (5) the spatial and temporal distribution of the floral resources of a dominant species, E. tricarpa. The results are discussed in relation to the evolutionary processes that may have lead to the flowering patterns, and the likely effects of these flowering patterns on blossom-feeding fauna of the Box-Ironbark region. Flowering observations were made for approximately 100 individually marked trees for each species (a total of 754 trees). The flower cover of each tree was assessed at a mean interval of 22 (+ 0.6) days for three years; 1997, 1998 and 1999. The seven species of eucalypt each had characteristic flowering seasons, the timing of which was similar each year. In particular, the timing of peak flowering intensity was consistent between years. Other spatial and temporal aspects of flowering patterns for each species, including the percentage of trees that flowered, frequency of flowering, intensity of flowering and duration of flowering, displayed significant variation between years, between forest stands (sites) and between individual trees within sites. All seven species displayed similar trends in flowering phenology over the study, such that 1997 was a relatively 'poor' flowering year, 1998 a 'good' year and 1999 an 'average' year in this study area. The floral character traits and flowering seasons of the seven Eucalyptus species suggest that each species has traits that can be broadly associated with particular pollinator types. Differences between species in floral traits were most apparent between 'summer' and 'winter' flowering species. Winter - flowering species displayed pollination syndromes associated with bird pollination and summer -flowering species displayed syndromes more associated with insect pollination. Winter - flowering E. tricarpa and E. leucoxylon flowers, for example, were significantly larger, and contained significantly greater volumes of nectar, than those of the summer flowering species, such as E. camaldulensis and E. melliodom. An examination of environmental and tree-specific factors was undertaken to investigate relationships between flowering patterns of individually marked trees of E. microcarpa and E. tricarpa and a range of measures that may influence the observed patterns. A positive association with tree-size was the most consistent explanatory variable for variation between trees in the frequency and intensity of flowering. Competition from near-neighbours, tree health and the number of shrubs within the canopy area were also explanatory variables. The relationship between tree size and flowering phenology was further examined by using the marked trees of all seven species, selected to represent five size-classes. Larger trees (≥40 cm DBH) flowered more frequently, more intensely, and for a greater duration than smaller trees. Larger trees provide more abundant floral resources than smaller trees because they have more flowers per unit area of canopy, they have larger canopies in which more flowers can be supported, and they provide a greater abundance of floral resources over the duration of the flowering season. Heterogeneity in the distribution of floral resources was further highlighted by the study of flowering patterns of E. tricarpa at several spatial and temporal scales. A total of approximately 5,500 trees of different size classes were sampled for flower cover along transects in major forest blocks at each of five sample dates. The abundance of flowers varied between forest blocks, between transects and among tree size - classes. Nectar volumes in flowers of E. tricarpa were sampled. The volume of nectar varied significantly among flowers, between trees, and between forest stands. Mean nectar volume per flower was similar on each sample date. The study of large numbers of individual trees for each of seven species was useful in obtaining quantitative data on flowering patterns of species' populations and individual trees. The timing of flowering for a species is likely to be a result of evolutionary selective forces tempered by environmental conditions. The seven species' populations showed a similar pattern in the frequency and intensity of flowering between years (e.g. 1998 was a 'good' year for most species) suggesting that there is some underlying environmental influence acting on these aspects of flowering. For individual trees, the timing of flowering may be influenced by tree-specific factors that affect the ability of each tree to access soil moisture and nutrients. In turn, local weather patterns, edaphic and biotic associations are likely to influence the available soil moisture. The relationships between the timing of flowering and environmental conditions are likely to be complex. There was no evidence that competition for pollinators has a strong selective influence on the timing of flowering. However, as there is year-round flowering in this community, particular types of pollinators may be differentiated along a temporal gradient (e.g. insects in summer, birds in winter). This type of differentiation may have resulted in the co-evolution of floral traits and pollinator types, with flowers displaying adaptations that match the morphologies and energy requirements of the most abundant pollinators in any particular season. Spatial variation in flowering patterns was evident at several levels. This is likely to occur because of variation in climate, weather patterns, soil types, degrees of disturbance and biotic associations, which vary across the Box-Ironbark region. There was no consistency among sites between years in flowering patterns suggesting that factors affecting flowering at this level are complex. Blossom-feeding animals are confronted with a highly spatially and temporally patchy resource. This patchiness has been increased with human exploitation of these forests leading to a much greater abundance of small trees and fewer large trees. Blossom-feeding birds are likely to respond to this variation in different ways, depending upon diet-breadth, mobility and morphological and behavioural characteristics. Future conservation of the blossom-feeding fauna of Box-Ironbark forests would benefit from the retention of a greater number of large trees, the protection and enhancement of existing remnants, and revegetation with key species, such as E. leucoxylon, E. microcarpa and E. tricarpa. The selective clearing of summer flowering species, which occur on the more fertile areas, may have negatively affected the year-round abundance and distribution of floral resources. The unpredictability of the spatial distribution of flowering patches within the region means that all remnants are likely to be important foraging areas in some years.

Intergenerational differences in food, physical activity, and body size perceptions among African migrants

We assessed intergenerational differences in food, physical activity, and body size perceptions among refugees and migrants from the Horn of Africa living in Victoria, Australia. We used a qualitative design and obtained data from 48 participants (18 individual interviews; 3 semistructured focus groups). Three major themes emerged: (a) food and physical activity, (b) preference of body size and social expectations, and (c) perceived consequences of various body sizes. For parents, large body size was perceived to equate with being beautiful and wealthy; slimness was associated with chronic illness and poverty. Parents adopted strategies that promoted weight gain in children. These included tailored food practices and restricting children’s involvement in physical activity. For young people, slimness was the ideal body size endorsed by their peers, and they adopted strategies to resist parental pressure to gain weight. Obesity-prevention programs in this subpopulation need to adopt a multigenerational approach.

Ecosystem relevance of variable jellyfish biomass in the Irish Sea between years, regions and water types

Monitoring the abundance and distribution of taxa is essential to assess their contribution to ecosystem processes. For marine taxa that are difficult to study or have long been perceived of little ecological importance, quantitative information is often lacking. This is the case for jellyfish (medusae and other gelatinous plankton). In the present work, 4 years of scyphomedusae by-catch data from the 2007-2010 Irish Sea juvenile gadoid fish survey were analysed with three main objectives: (1) to provide quantitative and spatially-explicit species-specific biomass data, for a region known to have an increasing trend in jellyfish abundance; (2) to investigate whether year-to-year changes in catch-biomass are due to changes in the numbers or in the size of medusa (assessed as the mean mass per individual), and (3) to determine whether inter-annual variation patterns are consistent between species and water masses. Scyphomedusae were present in 97% of samples (N=306). Their overall annual median catch-biomass ranged from 0.19 to 0.92gm-3 (or 8.6 to 42.4gm-2). Aurelia aurita and Cyanea spp. (Cyanea lamarckii and Cyanea capillata) made up 77.7% and 21.5% of the total catch-biomass respectively, but species contributions varied greatly between sub-regions and years. No consistent pattern was detected between the distribution and inter-annual variations of the two genera, and contrasting inter-annual patterns emerged when considering abundance either as biomass or as density. Significantly, A.aurita medusae were heavier in stratified than in mixed waters, which we hypothesize may be linked to differences in timing and yield of primary and secondary productions between water masses. These results show the vulnerability of time-series from bycatch datasets to phenological changes and highlight the importance of taking species- and population-specific distribution patterns into account when integrating jellyfish into ecosystem models.

Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks in 188 countries, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013

Background: The Global Burden of Disease, Injuries, and Risk Factor study 2013 (GBD 2013) is the first of a series of annual updates of the GBD. Risk factor quantification, particularly of modifiable risk factors, can help to identify emerging threats to population health and opportunities for prevention. The GBD 2013 provides a timely opportunity to update the comparative risk assessment with new data for exposure, relative risks, and evidence on the appropriate counterfactual risk distribution. Methods: Attributable deaths, years of life lost, years lived with disability, and disability-adjusted life-years (DALYs) have been estimated for 79 risks or clusters of risks using the GBD 2010 methods. Risk-outcome pairs meeting explicit evidence criteria were assessed for 188 countries for the period 1990-2013 by age and sex using three inputs: risk exposure, relative risks, and the theoretical minimum risk exposure level (TMREL). Risks are organised into a hierarchy with blocks of behavioural, environmental and occupational, and metabolic risks at the first level of the hierarchy. The next level in the hierarchy includes nine clusters of related risks and two individual risks, with more detail provided at levels 3 and 4 of the hierarchy. Compared with GBD 2010, six new risk factors have been added: handwashing practices, occupational exposure to trichloroethylene, childhood wasting, childhood stunting, unsafe sex, and low glomerular filtration rate. For most risks, data for exposure were synthesised with a Bayesian metaregression method, DisMod-MR 2.0, or spatial-temporal Gaussian process regression. Relative risks were based on meta-regressions of published cohort and intervention studies. Attributable burden for clusters of risks and all risks combined took into account evidence on the mediation of some risks such as high body-mass index (BMI) through other risks such as high systolic blood pressure and high cholesterol. Findings: All risks combined account for 57·2% (95% uncertainty interval [UI] 55·8-58·5) of deaths and 41·6% (40·1-43·0) of DALYs. Risks quantified account for 87·9% (86·5-89·3) of cardiovascular disease DALYs, ranging to a low of 0% for neonatal disorders and neglected tropical diseases and malaria. In terms of global DALYs in 2013, six risks or clusters of risks each caused more than 5% of DALYs: dietary risks accounting for 11·3 million deaths and 241·4 million DALYs, high systolic blood pressure for 10·4 million deaths and 208·1 million DALYs, child and maternal malnutrition for 1·7 million deaths and 176·9 million DALYs, tobacco smoke for 6·1 million deaths and 143·5 million DALYs, air pollution for 5·5 million deaths and 141·5 million DALYs, and high BMI for 4·4 million deaths and 134·0 million DALYs. Risk factor patterns vary across regions and countries and with time. In sub-Saharan Africa, the leading risk factors are child and maternal malnutrition, unsafe sex, and unsafe water, sanitation, and handwashing. In women, in nearly all countries in the Americas, north Africa, and the Middle East, and in many other high-income countries, high BMI is the leading risk factor, with high systolic blood pressure as the leading risk in most of Central and Eastern Europe and south and east Asia. For men, high systolic blood pressure or tobacco use are the leading risks in nearly all high-income countries, in north Africa and the Middle East, Europe, and Asia. For men and women, unsafe sex is the leading risk in a corridor from Kenya to South Africa. Interpretation: Behavioural, environmental and occupational, and metabolic risks can explain half of global mortality and more than one-third of global DALYs providing many opportunities for prevention. Of the larger risks, the attributable burden of high BMI has increased in the past 23 years. In view of the prominence of behavioural risk factors, behavioural and social science research on interventions for these risks should be strengthened. Many prevention and primary care policy options are available now to act on key risks.

Toward an operating system that supports parallel processing on nondedicated clusters

Present operating systems are not built to support parallel computing on clusters - they do not provide services to manage parallelism, i.e., to manage parallel processes and cluster resources. They do not provide support for both programming paradigms, Message Passing (MP) or Distributed Shared Memory (DSM). Due to poor operating systems, users must deal with computers of a cluster rather than to see this cluster as a single powerful computer. There is a need for cluster operating systems. We claim that it is possible to develop a cluster operating system that is able to efficiently manage parallelism, support MP and DSM and offer transparency. To substantiate this claim the first version of a cluster operating system managing parallelism and offering transparency, called GENESIS, has been developed.

Improving infant sleep and maternal mental health: a cluster randomised trial

Objectives: To determine whether a community-delivered intervention targeting infant sleep problems improves infant sleep and maternal well-being and to report the costs of this approach to the healthcare system.

Design: Cluster randomised trial.

Setting: 49 Maternal and Child Health (MCH) centres (clusters) in Melbourne, Australia.

Participants: 328 mothers reporting an infant sleep problem at 7 months recruited during October–November 2003.

Intervention: Behavioural strategies delivered over individual structured MCH consultations versus usual care.

Main outcome measures: Maternal report of infant sleep problem, depression symptoms (Edinburgh Postnatal Depression Scale (EPDS)), and SF-12 mental and physical health scores when infants were 10 and 12 months old. Costs included MCH sleep consultations, other healthcare services and intervention costs.

Results: Prevalence of infant sleep problems was lower in the intervention than control group at 10 months (56% vs 68%; adjusted OR 0.58 (95% CI: 0.36 to 0.94)) and 12 months (39% vs 55%; adjusted OR 0.50 (0.31 to 0.80)). EPDS scores indicated less depression at 10 months (adjusted mean difference –1.4 (–2.3 to –0.4) and 12 months (–1.7 (–2.6 to –0.7)). SF-12 mental health scores indicated better health at 10 months (adjusted mean difference 3.7 (1.5 to 5.8)) and 12 months (3.9 (1.8 to 6.1)). Total mean costs including intervention design, delivery and use of non-MCH nurse services were £96.93 and £116.79 per intervention and control family, respectively.

Conclusions: Implementing this sleep intervention may lead to health gains for infants and mothers and resource savings for the healthcare system.

Family, school, peer and individual influences on early adolescent alcohol use: first-year impact of the Resilient Families programme

Introduction and Aims:  This study aimed to examine: (a) the influence of family factors relative to school, peer and individual influences on the development of adolescent alcohol use during the first year of secondary school; and (b) the feasibility of preventing adolescent alcohol use by modifying family factors. Design and Methods:  Twenty-four schools in Melbourne, Australia were randomly assigned to either the 'Resilient Families' intervention or a control condition. A baseline cohort of 2315 grade 7 students (mean age 12.3 years) were followed-up one year later (n = 2128 for longitudinal analyses). A sub-set of parents (n = 1166) also returned baseline surveys. Results: The prevalence of lifetime alcohol use in year 7 was 33% and rose to 47% by year 8. Student-reported predictors of year 8 alcohol use included baseline alcohol [Odds Ratio (OR) 3.64] and tobacco use (2.68), and school friend's alcohol (1.41) and tobacco use (1.64). After adjusting for other influences, student-reported family factors were not maintained as significant predictors of year 8 alcohol use. Parent-report predictors of student-reported alcohol use included allowing alcohol use in the home (2.55), parental alcohol use (1.88) and child hyperactivity (1.85). Protective factors included attendance at brief parent education (0.60) and parent involvement in school education (0.65). Discussion and Conclusions: The intervention appeared to benefit education-related outcomes, but no overall effect in reducing student alcohol use was found in year 8. Intervention effects on alcohol misuse may become significant in later secondary school once the entire program has been implemented. Considerable alcohol use was detected in early secondary school,   suggesting that interventions to reduce alcohol use may be usefully implemented prior to this period.

Associations among individual, social, and environmental barriers and children's walking or cycling to school

Purpose. To examine associations among individual, social, and environmental barriers and children's walking or cycling to school.

Design. Exploratory cross-sectional study.

Setting. All eight capital cities in Australia.

Subjects. Parents (N = 720) of school-aged children (4-13 years; 27% response rate 49% parents of boys,).

Measures. Multivariate-adjusted odds ratios (OR) and 95% confidence intervals (CI) for parental reporting of barriers to their children's walking or cycling to school, based on a computer-assisted telephone interview.

Results. Forty-one percent of children walked or cycled to school at least once per week. Multivariable analyses found inverse associations with individual ("child prefers to be driven" [OR = 0.4, 95% CI = 0.3-0.6], "no time in the mornings" [OR 0.5, 95% CI = 0.3-0.8]); social ("worry child will take risk" [OR = 0.6, 95% CI = 0.3-0.9], "no other children to walk with" [OR = 0.7, 95% CI = 0.4-0.99], "no adults to walk with" [OR = 0.6, 95% CI = 0.4-0.9]); and environmental barriers ("too far to walk" [OR = 0.1, 95% CI = 0.0- 0.1], "no direct route" [OR = 0.4, 95% CI = 0.2-0. 7]) and positive associations with "concern child may he injured in a road accident" (OR = 1.9, 95% CI = 1.1-3.1) and active commuting.

Conclusion. Working with parents, schools, and local authorities to improve pedestrian, skills and environments may help to overcome barriers.

Describing individual incidents of sexual abuse: a review of research on the effects of multiple sources of information on children's reports

Objective: For successful prosecution of child sexual abuse, children are often required to provide reports about individual, alleged incidents. Although verbally or mentally rehearsing memory of an incident can strengthen memories, children’s report of individual incidents can also be contaminated when they experience other events related to the individual incidents (e.g., informal interviews, dreams of the incident) and/or when they have similar, repeated experiences of an incident, as in cases of multiple abuse.

Method: Research is reviewed on the positive and negative effects of these related experiences on the length, accuracy, and structure of children’s reports of a particular incident.

Results: Children’s memories of a particular incident can be strengthened when exposed to information that does not contradict what they have experienced, thus promoting accurate recall and resistance to false, suggestive influences. When the encountered information differs from children’s experiences of the target incident, however, children can become confused between their experiences—they may remember the content but not the source of their experiences.

Conclusions: We discuss the implications of this research for interviewing children in sexual abuse investigations and provide a set of research-based recommendations for investigative interviewers.

Dietary intakes and food sources of Omega-6 and Omega-3 polyunsaturated fatty acids.

Both n−6 and n−3 polyunsaturated fatty acids (PUFA) are recognized as essential nutrients in the human diet, yet reliable data on population intakes are limited. The aim of the present study was to ascertain the dietary intakes and food sources of individual n−6 and n−3 PUFA in the Australian population. An existing database with fatty acid composition data on 1690 foods was updated with newly validated data on 150 foods to estimate the fatty acid content of foods recorded as eaten by 10,851 adults in the 1995 Australian National Nutrition Survey. Average daily intakes of linoleic (LA), arachidonic (AA), α-linolenic (LNA), eicosapentaenoic (EPA), docosapentaenoic (DPA), and docosahexaenoic (DHA) acids were 10.8, 0.052, 1.17, 0.056, 0.026, and 0.106 g, respectively, with longchain (LC) n−3 PUFA (addition of FPA, DPA, and DHA) totaling 0.189 g; median intakes were considerably lower (9.0 g LA, 0.024 g AA, 0.95 g LNA, 0.008 g EPA, 0.006 g DPA, 0.015 g DHA, and 0.029 g LC n−3 PUFA). Fats and oils, meat and poultry, cereal-based products and cereals, vegetables, and nuts and seeds were important sources of n−6 PUFA, while cereal-based products, fats and oils, meat and poultry, cereals, milk products, and vegetable products were sources of LNA. As expected, seafood was the main source of LC n−3 PUFA, contributing 71%, while meat and eggs contributed 20 and 6%, respectively. The results indicate that the majority of Australians are failing to meet intake recommendations for LC n−3 PUFA (>0.2 g per day) and emphasize the need for strategies, to increase the availability and consumption of n−3-containing foods.

Individual, family, school, and community risk and protective factors for depressive symptoms in adolescents : a comparison of risk profiles for substance use and depressive symptoms

This study examines the relationship between adolescent depressive symptoms and risk and protective factors identified for substance use. A questionnaire, developed to measure these factors in a young persons community, family, school, peer group, and individual characteristics for substance use, was used to assess associations with self-reported depressive symptoms. Data were provided by a representative sample of 8984 secondary school students in Victoria, Australia. The prevalence of depressive symptoms was 10.5% (95% CI 9.2,12.0) for males and 21.7% (95% CI 20.3,23.7) for females. Depressive symptoms were associated with factors in all domains, with the strongest associations in the family domain. Strong relationships were found between the number of elevated risk and protective factors and depressive symptoms, maintained after adjusting for substance use. Patterns of associations were similar for users and nonsubstance users. The findings indicate that prevention programs targeting factors for substance use have the potential to impact on depression.

Individual foraging strategies in Australasian gannets (Morus serrator)

The individual foraging behaviour of Australasian gannets (Morus serrator) was studied using GPS and time-depth recorders. Gannets were found to forage at average maximum distances of 49 km (± 39 km) from the colony, with total foraging path lengths of 143 km (± 108 km) and foraging trip durations of 13.9 h (± 11 h). During foraging trips gannets spent on average 48.7% (± 17.6) of the time flying and made 37 (± 30.4) dives per trip, with an average maximum depth of 3.6 m (± 1 m). However, considerable variation in individual foraging strategies were recorded and these will be discussed in relation to individuals age, breeding experience and sex.

Isolation and characterization of polyunsaturated fatty acid producing Thraustochytrium species : screening of strains and optimization of omega-3 production

An isolation program targeting Thraustochytrids (marine fungoid protists) from 19 different Atlantic Canadian locations was performed. Sixty-eight isolates were screened for biomass, total fatty acid (TFA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) content. Analysis of fatty acid methyl ester results discerned four distinctive clusters based on fatty acid profiles, with biomass ranging from 0.1 to 2.3 g L−1, and lipid, EPA, and DHA contents ranging from 27.1 to 321.14, 2.97 to 21.25, and 5.18 to 83.63 mg g−1 biomass, respectively. ONC-T18, was subsequently chosen for further manipulations. Identified using 18S rRNA gene sequencing techniques as a Thraustochytrium sp., most closely related to Thraustochytrium striatum T91-6, ONC-T18 produced up to 28.0 g L−1 biomass, 81.7% TFA, 31.4% (w/w biomass) DHA, and 4.6 g L−1 DHA under optimal fermentation conditions. Furthermore, this strain was found to produce the carotenoids and xanthophylls astaxanthin, zeaxanthin, canthaxanthin, echinenone, and β-carotene. Given this strain’s impressive productivity when compared to commercial strains, such as Schizochytrium sp. SR21 (which has only 50% TFA), coupled with its ability to grow at economical nitrogen and very low salt concentrations (2 g L−1), ONC-T18 is seen as an ideal candidate for both scale-up and commercialization.

Psychosocial precursors and correlates of differing internalizing trajectories from 3 to 15 years

Psychosocial precursors and correlates of parent-reported internalizing behavior trajectories across the age span of 3–15 years were explored using a community-based cohort of Australian children. Six internalizing trajectories had previously been identified for both girls (N = 810) and boys (N = 874) in this sample, comprising stable low, high, decreasing, and increasing pathways. Infancy and toddler temperamental traits (inhibition/shyness, irritability), behavior problems, and parent–child relationship difficulties constituted significant risks for subsequent problematic internalizing profiles. Several gender-specific trends were evident, with temperamental reactivity and shyness, less optimal parenting, and peer difficulties more salient for girls on increasing trajectories whereas externalizing problems were more prominent among boys on increasing trajectories. Factors associated with recovery from elevated symptoms included higher levels of social competence, better parent and peer relations, and more positive school adjustment. Findings suggest that individual characteristics and relationship experiences may be involved in the development and course of internalizing problems.

Population structure in the highly fragmented range of Tor douronensis (Cyprinidae) in Sarawak, Malaysia revealed by microsatellite DNA markers

1. Understanding the structure of threatened populations, particularly those that exist in degraded or fragmented habitats is crucial for their effective management and conservation. Recently developed methods of individual-based analysis of genetic data provide an unprecedented opportunity to understand the relationships amongst fragmented populations.

2. In the present study, population structure of an important cyprinid species (Tor douronensis), which is indigenous to Sarawak, Malaysia, is investigated as part of an ongoing conservation effort to restore threatened wild populations of the species. The population structure inferred using data from seven autosomal microsatellite loci was generally consistent with geography and habitat fragmentation.

3. The results indicate that there are two well-defined clusters of T. douronensis in Sarawak, namely the 'northeastern' and the 'southwestern' clusters. In addition, a further subdivision was observed in each of the clusters distributed between river systems. Low levels of gene flow were also observed and migrants between habitat fragments were identified, possibly resulting from human-mediated translocations.

4. Implications of the findings for management and conservation of T. douronensis are discussed.