Effects of habitat modification in mangroves on the structure of mollusc and crab assemblages

The abundance and species richness of mollusc and crab assemblages were examined in a subtropical mangrove forest in Moreton Bay, Queensland, Australia, which has been disturbed and damaged by the construction of a wooden boardwalk and a path. Sections of the forest immediately adjacent to the boardwalk and path were compared with reference areas to determine whether changes to the small-scale structural complexity within the forest affected the benthic fauna. The disturbed area was characterised by having 65-80% fewer pneumatophores, significantly fewer species and individuals of molluscs, but significantly more species and individuals of crabs than the reference areas. The abundance of mangrove pneumatophores and the attached epiphytic algae were manipulated at two sites to determine whether observed differences in these features could account for the differences in the assemblage of molluscs in the disturbed area of the forest compared with reference areas. Five experimental treatments were used: undisturbed controls, pneumatophore removals (abundance reduced by ca. 65%), epiphytic algal removals (algae removed from ca. 65% of pneumatophores), pneumatophore disturbance controls and algal disturbance controls. The experimental reduction of the abundance of mangrove pneumatophores and the associated epiphytic algae led to significant declines (by as much as 83%) in the number of molluscs utilising the substratum in the modified plots. There was no significant difference in the abundance of molluscs in the pneumatophore and algal removal plots suggesting any effect was primarily related to removal of the epiphytic algae from the surface of the pneumatophores. The responses by the biota to the changes in the physical environment demonstrate that even relatively small-scale modifications to the physical structure of subtropical mangrove forests can lead to significant effects on the diversity and abundance of macrobenthic organisms in these habitats. Such modifications have the potential to cause cascading effects at higher trophic levels with a deterioration in the value of these habitats as nursery and feeding grounds. Future efforts at conservation of these estuarine environments must focus on the prevention or reduction of modifications to the physical structure and integrity of the system, rather than just on the prevention of loss of entire patches of habitat. (C) 2000 Elsevier Science B.V. All rights reserved.

Modernity Contextualises New Zealand's Royal Commission on Genetic Modification: A Discourse Analysis

The New Zealand's Royal Commission on Genetic Modification (RCGM)'s report was released in the year 2001. RCGM's findings supports the ongoing development of genetic engineering in New Zealand and recommends the recommencement of genetic modification field trials.

Environmental Risk Factors for Parkinson's Disease

Parkinson’s disease (PD) is a progressive, degenerative, neurological disease. The progressive disability associated with PD results in substantial burdens for those with the condition, their families and society in terms of increased health resource use, earnings loss of affected individuals and family caregivers, poorer quality of life, caregiver burden, disrupted family relationships, decreased social and leisure activities, and deteriorating emotional well-being. Currently, no cure is available and the efficacy of available treatments, such as medication and surgical interventions, decreases with longer duration of the disease. Whilst the cause of PD is unknown, genetic and environmental factors are believed to contribute to its aetiology. Descriptive and analytical epidemiological studies have been conducted in a number of countries in an effort to elucidate the cause, or causes, of PD. Rural residency, farming, well water consumption, pesticide exposure, metals and solvents have been implicated as potential risk factors for PD in some previous epidemiological studies. However, there is substantial disagreement between the results of existing studies. Therefore, the role of environmental exposures in the aetiology of PD remains unclear. The main component of this thesis consists of a case-control study that assessed the contribution of environmental exposures to the risk of developing PD. An existing, previously unanalysed, dataset from a local case-control study was analysed to inform the design of the new case-control study. The analysis results suggested that regular exposure to pesticides and head injury were important risk factors for PD. However, due to the substantial limitations of this existing study, further confirmation of these results was desirable with a more robustly designed epidemiological study. A new exposure measurement instrument (a structured interviewer-delivered questionnaire) was developed for the new case-control study to obtain data on demographic, lifestyle, environmental and medical factors. Prior to its use in the case-control study, the questionnaire was assessed for test-retest repeatability in a series of 32 PD cases and 29 healthy sex-, age- and residential suburb-matched electoral roll controls. High repeatability was demonstrated for lifestyle exposures, such as smoking and coffee/tea consumption (kappas 0.70-1.00). The majority of environmental exposures, including use of pesticides, solvents and exposure to metal dusts and fumes, also showed high repeatability (kappas >0.78). A consecutive series of 163 PD case participants was recruited from a neurology clinic in Brisbane. One hundred and fifty-one (151) control participants were randomly selected from the Australian Commonwealth Electoral Roll and individually matched to the PD cases on age (± 2 years), sex and current residential suburb. Participants ranged in age from 40-89 years (mean age 67 years). Exposure data were collected in face-to-face interviews. Odds ratios and 95% confidence intervals were calculated using conditional logistic regression for matched sets in SAS version 9.1. Consistent with previous studies, ever having been a regular smoker or coffee drinker was inversely associated with PD with dose-response relationships evident for packyears smoked and number of cups of coffee drunk per day. Passive smoking from ever having lived with a smoker or worked in a smoky workplace was also inversely related to PD. Ever having been a regular tea drinker was associated with decreased odds of PD. Hobby gardening was inversely associated with PD. However, use of fungicides in the home garden or occupationally was associated with increased odds of PD. Exposure to welding fumes, cleaning solvents, or thinners occupationally was associated with increased odds of PD. Ever having resided in a rural or remote area was inversely associated with PD. Ever having resided on a farm was only associated with moderately increased odds of PD. Whilst the current study’s results suggest that environmental exposures on their own are only modest contributors to overall PD risk, the possibility that interaction with genetic factors may additively or synergistically increase risk should be considered. The results of this research support the theory that PD has a multifactorial aetiology and that environmental exposures are some of a number of factors to contribute to PD risk. There was also evidence of interaction between some factors (eg smoking and welding) to moderate PD risk.

Test–retest repeatability of self-reported environmental exposures in Parkinson’s disease cases and healthy controls

There is substantial disagreement among published epidemiological studies regarding environmental risk factors for Parkinson’s disease (PD). Differences in the quality of measurement of environmental exposures may contribute to this variation. The current study examined the test–retest repeatability of self-report data on risk factors for PD obtained from a series of 32 PD cases recruited from neurology clinics and 29 healthy sex-, age-and residential suburb-matched controls. Exposure data were collected in face-to-face interviews using a structured questionnaire derived from previous epidemiological studies. High repeatability was demonstrated for ‘lifestyle’ exposures, such as smoking and coffee/tea consumption (kappas 0.70–1.00). Environmental exposures that involved some action by the person, such as pesticide application and use of solvents and metals, also showed high repeatability (kappas>0.78). Lower repeatability was seen for rural residency and bore water consumption (kappa 0.39–0.74). In general, we found that case and control participants provided similar rates of incongruent and missing responses for categorical and continuous occupational, domestic, lifestyle and medical exposures.

Modification of arthropod vector competence via symbiotic bacteria

Some of the world's most devastating diseases are transmitted by arthropod vectors. Attempts to control these arthropods are currently being challenged by the widespread appearance of insecticide resistance. It is therefore desirable to develop alternative strategies to complement existing methods of vector control. In this review, Charles Beard, Scott O'Neill, Robert Tesh, Frank Richards and Serap Aksoy present an approach for introducing foreign genes into insects in order to confer refractoriness to vector populations, ie. the inability to transmit disease-causing agents. This approach aims to express foreign anti-parasitic or anti-viral gene products in symbiotic bacteria harbored by insects. The potential use of naturally occurring symbiont-based mechanisms in the spread of such refractory phenotypes is also discussed.

Bringing Us Home: Cohousing and the Environmental Possibilities of Reuniting People with Neighbourhoods

Cohousing is a form of intentional community which has made a significant contribution to urban environmentalism by recreating the neighbourhood as the setting for engagement with the world beyond the front door.

Spatial Technologies: What use are they to managers of environmental lands?

This paper reviews the potential use of three types of spatial technology to land managers, namely satellite imagery, satellite positioning systems and supporting computer software. Developments in remote sensing and the relative advantages of multispectral and hyperspectral images are discussed. The main challenge to the wider use of remote sensing as a land management tool is seen as uncertainty whether apparent relationships between biophysical variables and spectral reflectance are direct and causal, or artefacts of particular images. Developments in satellite positioning systems are presented in the context of land managers’ need for position estimates in situations where absolute precision may or may not be required. The role of computer software in supporting developments in spatial technology is described. Spatial technologies are seen as having matured beyond empirical applications to the stage where they are useful and reliable land management tools. In addition, computer software has become more user-friendly and this has facilitated data collection and manipulation by semi-expert as well as specialist staff.