Landscape-scale effects of fire on bird assemblages : does pyrodiversity beget biodiversity?

Aim A common strategy for conserving biodiversity in fire-prone environments is to maintain a diversity of post-fire age classes at the landscape scale, under the assumption that 'pyrodiversity begets biodiversity'. Another strategy is to maintain extensive areas of a particular seral state regarded as vital for the persistence of threatened species, under the assumption that this will also cater for the habitat needs of other species. We investigated the likely effects of these strategies on bird assemblages in tree mallee vegetation, characterized by multi-stemmed Eucalyptus species, where both strategies are currently employed.

Location The semi-arid Murray Mallee region of south-eastern Australia.

Methods We systematically surveyed birds in 26 landscapes (each 4-km diameter), selected to represent gradients in the diversity of fire age classes and the proportion of older vegetation (>35years since fire). Additional variables were measured to represent underlying vegetation- or fire-mediated properties of the landscape, as well as its biogeographic context. We used an information-theoretic approach to investigate the relationships between these predictor variables and the species richness of birds (total species, threatened species and rare species).

Results Species richness of birds was not strongly associated with fire-mediated heterogeneity. Species richness was associated with increasing amounts of older vegetation in landscapes, but not with the proportion of recently burned vegetation in landscapes.

Main conclusions The preference of many mallee birds for older vegetation highlights the risk of a blanket application of the 'pyrodiversity begets biodiversity' paradigm. If application of this paradigm involved converting large areas from long unburned to recently burned vegetation to increase fire-mediated heterogeneity in tree mallee landscapes, our findings suggest that this could threaten birds. This research highlights the value of adopting a landscape-scale perspective when evaluating the utility of fire-management strategies intended to benefit biodiversity.

Variation in the impact of non-native seaweeds along gradients of habitat degradation: a meta-analysis and an experimental test

Biological invasions are acknowledged among the main drivers of global changes in biodiversity. Despite compelling evidence of species interactions being strongly regulated by environmental conditions, there is a dearth of studies investi-gating how the effects of non-native species vary among areas exposed to different anthropogenic pressures. Focusing on marine macroalgae, we performed a meta-analysis to test whether and how the direction and magnitude of their effects on resident communities and species varies in relation to cumulative anthropogenic impact levels. The relationship between human impact levels and non-native species impact intensity emerged only for a reduced subset of the response variables examined. Yet, there was a trend for the effects of non-native species on community biomass and abundance and on species abundance to become less negative at heavily impacted sites. By contrast, the magnitude of negative effects of seaweed on community evenness tended to increase with human impact levels. The hypothesis of decreasing severity of invader’ impacts along a gradient of habitat degradation was also tested experimentally at a regional scale by comparing the effects of the removal of non-native alga,
Caulerpa cylindracea, on resident assemblages among rocky reefs exposed to different anthropogenic pressures. Assemblages at urban and pristine site did not differ when invaded, but did so when C. cylindracea was removed. Our results suggest that, despite the generally weak relationship between human impacts levels and non-native species impacts, more negative impacts can be expected in less stressful environments (i.e. less degraded or pristine sites), where competitive interactions are presumably the driving force structuring resident communities. Implementing strategies for controlling the establishment of non-native seaweeds should be, thus, considered a priority for preserving biodiversity in relatively pristine areas. On the other hand, control of invaders at degraded sites could be warranted to lessen their role as propagule sources

The role and contribution of private land in Victoria to biodiversity conservation and the protected area system

The distribution and attributes of properties involved in three major programs for biodiversity protection on private land in Victoria, Australia, was investigated to determine their role in relation to the reserve system. Overlaying of dowsets in a geographic information system, with particular emphasis on property distribution in relation to bioregional and population centres, was undertaken. Land for Wildlife agreements had greater numbers of properties and total area protected in all bioregions throughout the State, yet average protected area sizes were lower than those of conservation covenants and Trust for Nature reserves. A combination of large bioregional area and human population size tended to attract more private conservation properties and, to a lesser extent, the total area they protected. The potential contribution that such properties made to biodiversity conservation varied between bioregions. Inclusion of properties within a national reserve framework is proposed to improve the coordination and effectiveness of conservation measures.

High Stakes: Lessons from stakeholder groups in the biodiversity conservation network

Research in common property, participatory resource management, and community development points to the central importance of organizational arrangements in conservation and development interventions. The dilemma facing contemporary conservation practitioners is how best to assist and facilitate such arrangements in support of participatory resource management and sustainable livelihoods, given the range of organizations, societal processes, and structures in which interventions might engage. This article presents some key findings from a study of stakeholder groups at 4 project sites, with information from a further 16 sites, in the Biodiversity Conservation Network: (1) Longstanding organizations had an established community niche, but could become bogged down in bureaucratic procedures; (2) poor communication between organizations was common and could undermine resource management; and (3) charismatic individuals and local elite interests could dominate groups, diminishing their representativeness. Based on these findings, the article argues that conservation professionals need to build their capacity as facilitators and negotiators, paying greater attention to how stakeholder groups form and function, their links to wider arenas, and the aims and positions of groups and individuals.

Land retirement: a biodiversity policy for the rangelands of Western N.S.W.

In this article we examine land retirement as a biodiversity policy option for the rangelands of Western NSW, a region seriously under-represented in biodiversity provision. We argue that the use of policies that rely on moral suasion, education and minimal costsharing will not yield the level of on-farm biodiversity provision demanded by society. Instead, a much greater commitment to the use of monetary incentives to induce the voluntary cooperation and production of biodiversity is required. The analysis explains the importance in policy design of determining transparent, meaningful and achievable objectives in delivering cost-effective environmental outcomes. We propose a land retirement
policy that rakes account of environmental, economic and political criteria. Finally, our land retirement proposal is supported quantitatively by benefit-cost analysis.

How well do ecosystem-based planning units represent different componenets of biodiversity?

There are many proposals for managing biodiversity by using surrogates, such as umbrella, indicator, focal, and flagship species. We use the term biodiversity management unit for any ecosystem-based classificatory scheme for managing biodiversity. The sufficiency of biodiversity management unit classification schemes depends upon (1) whether different biotic elements (e.g., trees, birds, reptiles) distinguish between biodiversity management units within a classification (i.e., coherence within classes}; and (2) whether different biotic elements agree upon similarities and dissimilarities among biodiversity management unit classes (i.e., conformance among classes). Recent evaluations suggest that biodiversity surrogates based on few or single taxa are not useful. Ecological vegetation classes are an ecosystem-based classification scheme used as one component for biodiversity management in Victoria, Australia. Here we evaluated the potential for ecological vegetation classes to be used as biodiversity management units in the box-ironbark ecosystem of central Victoria, Australia. Eighty sites distributed among 14 ecological vegetation classes were surveyed in the same ways for tree species, birds, mammals, reptiles, terrestrial invertebrates, and nocturnal flying insects. Habitat structure and geographic separations also were measured, which, with the biotic elements, are collectively referred to as variables. Less than half of the biotic element-ecological vegetation class pairings were coherent. Generalized Mantel tests were used to examine conformance among variables with respect to ecological vegetation classes. While most tests were not significant, birds, mammals, tree species, and habitat structure together showed significant agreement on the rating of similarities among ecological vegetation classes. In this system, use of ecological vegetation classes as biodiversity management units may account reasonably well for birds, mammals, and trees; but reptiles and invertebrates would not be accommodated. We conclude that surrogates will usually have to be augmented or developed as hierarchies to provide general representativeness.

Porous titanium with porosity gradients for biomedical applications

Highly porous titanium and titanium alloys with an open cell structure are promising implant materials due to their low elastic modulus, excellent bioactivity, biocompatibility and the ability for bone regeneration. However, the mechanical strength of the porous titanium decreases dramatically with increasing porosity, which is a prerequisite for the ingrowth of new bone tissues and vascularization. In the present study, porous titanium with porosity gradients, i.e. solid core with highly porous outer shell was successfully fabricated using a powder metallurgy approach. Satisfactory mechanical properties derived from the solid core and osseointegration capacity derived from the outer shell can be achieved simultaneously through the design of the porosity gradients of the porous titanium. The outer shell of porous titanium exhibited a porous architecture very close to
that of natural bone, i.e. a porosity of 70% and pore size distribution in the range of 200 - 500 μm. The peak stress and the elastic modulus of the porous titanium with a porosity gradient (an overall porosity 63%) under compression were approximately 152 MPa and 4 GPa, respectively. These
properties are very close to those of natural bone. For comparison, porous titanium with a uniform porosity of 63% was also prepared and haracterised in the present study. The peak stress and the elastic modulus were 109 MPa and 4 GPa, respectively. The topography of the porous titanium
affected the mechanical properties significantly.

Do socioeconomic gradients in women's health widen over time and with age?

A population-based study was conducted to investigate changes over time in women's well-being and health service use by socio-economic status and whether these varied by age. Data from 12,328 mid-age women (aged 45–50 years in 1996) and 10,430 older women (aged 70–75 years) from the Australian Longitudinal Study on Women's Health were analysed. The main outcome measures were changes in the eight dimensions of the Short Form General Health Survey (SF-36) adjusted for baseline scores, lifestyle and behavioural factors; health care utilisation at Survey 2; and rate of deaths (older cohort only). Cross-sectional analyses showed clear socioeconomic differentials in well-being for both cohorts. Differential changes in health across tertiles of socioeconomic status (SES) were more evident in the mid-age cohort than in the older cohort. For the mid-aged women in the low SES tertile, declines in physical functioning (adjusted mean change of –2.4, standard error (SE) 1.1) and general health perceptions (−1.5, SE 1.1) were larger than the high SES group (physical functioning –0.8 SE 1.1, general health perceptions –0.8 SE 1.2). In the older cohort, changes in SF-36 scores over time were similar for all SES groups but women in the high SES group had lower death rates than women in the low SES group (relative risk: 0.79, 95% confidence interval 0.64–0.98). Findings suggest that SES differentials in physical health seem to widen during women's mid-adult years but narrow in older age. Nevertheless, SES remains an important predictor of health, health service use and mortality in older Australian women.

Seeking mechanisms for improved integration of biodiversity issues in regional natural resource management planning

This article reviews the literature on natural resource management (NRM) planning in Australia, with particular consideration given to exploring how regions might better integrate biodiversity conservation into catchment or regional planning in ways that lead to improved biodiversity conservation practice in the field. Many of the findings of the review are generic, affecting a range of NRM issues (including biodiversity conservation) and the NRM planning process itself, whilst other findings are specific to conservation of biodiversity. Factors affecting the integration of biodiversity include the organizational characteristics of the regional NRM body, clarity in the region of the responsibilities across the three tiers of government, effective participation of stakeholders, existence of detailed NRM plans that include sound biodiversity data and management principles, access to interpreted information, use of a mix of policy instruments capable of delivering biodiversity goals, and effective monitoring frameworks and tools to track the return on investment. there is considerable variability in the ways that NRM planning is practiced across Australia, at the enterprise, regional or catchment levels. However, an overarching issue is how well the planning caters for differences across space, time and human values and this article attempts to identify the considerations that impact on that requirement.

Freshwater finfish biodiversity and conservation: an Asian perspective

Aspects on biodiversity and conservation of the ichthyofauna in the Asian region, in comparison to that of Africa, Europe and North America have been relatively less documented. This paper attempts to evaluate the above aspects in the East, and South and Southeast Asia based on available information in the literature. The familial diversity in inland waters in Asia (121 families) is considerably higher than in African and Latin American. Also, the finfish faunal diversity of 21 major river basins in East, and South and Southeast Asian indicate that species diversity is not necessarily related to familial diversity. The fish fauna in the region considered presently is highly diverse with an estimated cumulative total of 7447 species. Amongst the freshwater fishes the dominant groups are cyprinids (Cyprinidae, about 1000 species), loaches (about 400 species) of the families Balitoridae and Cobitiidae, gobids (Gobiidae, 300 species), catfishes (Bagridae, about 100 species), and the Osphronemidae (85 species). In the region, 462 freshwater finfish species are reckoned to be threatened, accounting for 17.5% of the all finfish species in this status in the world. In the region there are 66 species that are critically endangered and/or endangered, of which 32 are cyprinids, 14 of which are endemic to Lake Lanao, Mindano Island, Philippines. The diversity of freshwater fish species in the region was significantly related to the land area of the different countries in the following manner:

ln (species ratio) = ln 0.384 (land area in km2) + 0.651( R² = 0.628; p < 0.001).

In addition, the fish species diversity in the major river basins of the region was also found to be positively related to the basin area:

ln (Species richness index) = - 0.789 ln (Area) + 9.368( R² = 0.748; p < 0.001).

Based on above relationship, the predicted fish species richness did not necessarily correlate to river basin size, and rivers with small basins were shown to have high indices. The paper also attempts to evaluate the reasons affecting fish species diversity in the region and suggests mitigating measures.