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McCall S.C.,University of Melbourne | McCarthy M.A.,University of Melbourne | van der Ree R.,University of Melbourne | Harper M.J.,Australian Research Center for Urban Ecology | And 2 more authors.
Ecology and Society | Year: 2010

Roads and traffic are prominent components of most landscapes throughout the world, and their negative effects on the natural environment can extend for hundreds or thousands of meters beyond the road. These effects include mortality of wildlife due to collisions with vehicles, pollution of soil and air, modification of wildlife behavior in response to noise, creation of barriers to wildlife movement, and establishment of dispersal conduits for some plant and animal species. In southeast Australia, much of the remaining habitat for the squirrel glider, Petaurus norfolcensis, is located in narrow strips of Eucalyptus woodland that is adjacent to roads and streams, as well as in small patches of woodland vegetation that is farther from roads. We evaluated the effect of traffic volume on squirrel gliders by estimating apparent annual survival rates of adults along the Hume Freeway and nearby low-traffic-volume roads. We surveyed populations of squirrel gliders by trapping them over 2.5 years, and combined these data with prior information on apparent survival rates in populations located away from freeways to model the ratio of apparent annual survival rates in both site types. The apparent annual survival rate of adult squirrel gliders living along the Hume Freeway was estimated to be approximately 60% lower than for squirrel gliders living near local roads. The cause of the reduced apparent survival rate may be due to higher rates of mortality and/or higher emigration rates adjacent to the Hume Freeway compared with populations near smaller country roads. Management options for population persistence will be influenced by which of these factors is the primary cause of a reduced apparent survival rate. © 2010 by the author(s).


van der Ree R.,Australian Research Center for Urban Ecology | Cesarini S.,Monash University | Sunnucks P.,Monash University | Moore J.L.,Australian Research Center for Urban Ecology | Taylor A.,Monash University
Ecology and Society | Year: 2010

Roads and traffic reduce landscape connectivity and increase rates of mortality for many species of wildlife. Species that glide from tree to tree may be strongly affected by roads and traffic if the size of the gap between trees exceeds their gliding capability. Not only are wide roads likely to reduce crossing rates, but mortality may also be increased if gliders that do cross have poor landing opportunities. The road-crossing behavior of 47 squirrel gliders (Petaurus norfolcensis) was investigated in southeast Australia using radio-tracking. The proportion of gliders crossing one or both roadways of a freeway where trees were present or absent from the center median was compared to that at single-lane country roads (control). The proportion of gliders crossing the road at control sites (77%) was similar to the proportion that crossed one or both roadways at the freeway with trees in the median (67%), whereas only a single male (6%) crossed the freeway where trees were absent from the median. The frequency of crossing for each individual was also similar at control sites and freeway sites with trees in the median. The almost complete lack of crossing at sites where trees were absent from the median was attributed to the wider gap in canopy (50 - 64 m vs. 5 - 13 m at sites with trees in the median). This suggests that traffic volume, up to 5,000 vehicles per day on each roadway, and the other characteristics of the freeway we studied are not in themselves complete deterrents to road crossing by squirrel gliders. This study demonstrates that retaining and facilitating the growth of tall trees in the center median of two-way roads may mitigate the barrier effect of roads on gliders, thus contributing positively to mobility and potentially to connectivity. This information will be essential for the assessment of road impacts on gliding species using population viability models. © 2010 by the author(s).


Simmons J.M.,Monash University | Simmons J.M.,Australian Center for Biodiversity | Sunnucks P.,Monash University | Sunnucks P.,Australian Center for Biodiversity | And 3 more authors.
Ecology and Society | Year: 2010

Habitat fragmentation continues to occur despite increasing evidence of its adverse effects on ecosystems. One of the major detrimental effects of roads and traffic is the creation of barriers or filters to the movement of wildlife, ultimately disconnecting some populations. Our understanding of the extent to which roads reduce the movement of biota is mostly based on field-based observational methods of inferring animal movement, and to a much smaller extent, on allele frequency-based genetic analyses. Field-based methods, as it is typically feasible to apply them, tend to be informative at fine temporal and spatial scales. Allele frequency-based genetic methods are informative at broad geographic scales but at timescales usually greater than recent disturbance events. Contemporary analyses based on genotypes of individual organisms (called genotypic approaches herein) can augment these other approaches. They can be informative at fine spatial and temporal scales, are readily scaled up, and are complementary to the other field-based approaches. In genotypic analyses, every capture can be effectively a recapture, relieving a major limitation in sample size. They can evaluate the influence of even recently constructed roads on movements and their emergent effects on important population processes at the spatial and temporal scales of interest to wildlife and infrastructure managers. Information derived from genetic and field-based methods can be used to model the viability of populations influenced by roads and to evaluate and monitor mitigation efforts. Despite some excellent examples, we suggest that such applications are still rare relative to their potential. This paper emphasizes some of the detailed inferences that can be made using different types of genetic analyses, and suggests paths by which researchers in road ecology can incorporate genetic approaches. We recommend that the proven capacities of genetic techniques be routinely explored as approaches to quantify the diverse influences of roads on wildlife populations. With appropriate expertise, molecular ecology can be done extremely inexpensively. It is conducted within the same funding frameworks as field-based approaches and, in budgeting funding applications, molecular ecology maintenance costs are about 20-30% of payroll, in line with other disciplines and approaches. This and other common arguments against application of genetic approaches are often based on misconceptions, or limitations that no longer apply. © 2010 by the author(s).


Newbound M.,University of Melbourne | Newbound M.,Australian Research Center for Urban Ecology | Mccarthy M.A.,University of Melbourne | Mccarthy M.A.,Australian Research Center for Urban Ecology | Lebel T.,National Herbarium of Victoria
Landscape and Urban Planning | Year: 2010

Although the functional importance of fungi in ecosystems is well recognised, there has been comparatively little focus on their role in urban systems and the ways fungi may be affected by urbanisation. This review advances our knowledge in these areas by drawing together urban fungal studies along with relevant broader research on both fungal and urban ecology. From these studies we discuss the ecological roles of fungi, such as their beneficial interactions with plants and animals. We also highlight the ecological processes that could potentially threaten the persistence of fungi in cities. Among these are the dangers of soil pollution and changes to the biota that form relationships with fungi. We conclude by suggesting some ways forward for research in this area, as well as considering the potential for fungal conservation in cities if their ecology can be understood and communicated to land managers. © 2010 Elsevier B.V.


Williams N.S.G.,University of Melbourne | Williams N.S.G.,Australian Research Center for Urban Ecology | Rayner J.P.,University of Melbourne | Raynor K.J.,University of Melbourne
Urban Forestry and Urban Greening | Year: 2010

There is increasing public, industry and government interest in establishing green roofs in Australian cities due to their demonstrated environmental benefits. While a small number of green roofs have been constructed in Australia, most are roof gardens or intensive green roofs. Despite their potential as a climate change adaptation and mitigation tool and their widespread use in the northern hemisphere, there are very few examples of extensive green roofs in Australia. One of the major barriers to increasing the prevalence of extensive green roofs in Australia is the lack of scientific data available to evaluate their applicability to local conditions. Relying on European and North American experience and technology is problematic due to significant differences in climate, available substrates and plants. This paper examines green roofs in Australia, discusses the challenges to increasing their use and the major information gaps that need to be researched to progress the industry in Australia. © 2010 Elsevier GmbH.


Soanes K.,Australian Research Center for Urban Ecology | Soanes K.,University of Melbourne | Lobo M.C.,Australian Research Center for Urban Ecology | Lobo M.C.,University of Melbourne | And 4 more authors.
Biological Conservation | Year: 2013

Wildlife crossing structures are commonly used to mitigate the barrier and mortality impacts of roads on wildlife. For arboreal mammals, canopy bridges, glider poles and vegetated medians are used to provide safe passage across roads. However, the effectiveness of these measures is unknown. We investigate the effect of canopy bridges, glider poles and vegetated medians on squirrel glider movement across a freeway in south-east Australia. We monitored structures directly using motion-triggered cameras and passive integrated transponder (PIT) scanners. Further, post-mitigation radio-tracking was compared to a pre-mitigation study. Squirrel gliders used all structure types to cross the freeway, while the unmitigated freeway remained a barrier to movement. However, movement was not restored to the levels observed at non-freeway sites. Nevertheless, based on the number and frequency of individuals crossing, mitigation is likely to provide some level of functional connectivity. The rate of crossing increased over several years as animals habituated to the structure. We also found that crossing rate can be a misleading indicator of effectiveness if the number of individuals crossing is not identified. Therefore, studies should employ long-term monitoring and identify individuals crossing if inferences about population connectivity are to be made from movement data alone. © 2012 Elsevier Ltd.


Garrard G.E.,University of Melbourne | Garrard G.E.,RMIT University | Mccarthy M.A.,University of Melbourne | Williams N.S.G.,University of Melbourne | And 3 more authors.
Methods in Ecology and Evolution | Year: 2013

Imperfect detectability is a critical source of variation that limits ecological progress and frustrates effective conservation management. Available modelling methods provide valuable detectability estimates, but these are typically species-specific. We present a novel application of time-to-detection modelling in which detectability of multiple species is a function of plant traits and observer characteristics. The model is demonstrated for plants in a temperate grassland community in south-eastern Australia. We demonstrate that detectability can be estimated using observer experience, species population size and likelihood of flowering. The inclusion of flower colour and species distinctiveness improves the capacity of the model to predict detection rates for new species. We demonstrate the application of the general model to plants in a temperate grassland community, but this modelling method may be extended to other communities or taxa for which time-to-detection models are appropriate. Detectability is influenced by traits of the species and the observer. General models can be used to derive detectability estimates where repeat survey data, point counts or mark-recapture data are not available. As these data are almost always absent for species of conservation concern, general models such as ours will be useful for informing minimum survey requirements for monitoring and impact assessment, without the delays and costs associated with data collection. © 2012 The Authors. Methods in Ecology and Evolution. © 2012 British Ecological Society.


Kendal D.,University of Melbourne | Kendal D.,Australian Research Center for Urban Ecology | Williams K.J.H.,University of Melbourne | Williams N.S.G.,University of Melbourne | Williams N.S.G.,Australian Research Center for Urban Ecology
Landscape and Urban Planning | Year: 2012

Gardens are ubiquitous in western cities, comprising up to a third of the total urban area and often containing a majority of the vegetation present. Gardens are the cumulative result of many individual plant choices, yet we know relatively little about the role of preference in these choices. We investigated peoples' preference for different garden plants and reasons for plant choices using a postal questionnaire (n= 224) containing 30 colour photos of garden plants and questions about gardening behaviour. Preferences were compared with the plants growing in the gardens of 48 randomly selected respondents. Objectively measured plant traits were used to relate preferences to the plants growing in people's gardens. Significant relationships were found between survey responses and both the traits and taxonomy of plants growing in respondent gardens. The results also show that people's preferences are very diverse, and that these preferences were related both to aesthetic traits such as flower size, leaf width and foliage colour, and non-visual traits such as nativeness and drought tolerance. Together these findings provide evidence that garden floras have responded to their social environment, and suggests that the very high levels of diversity observed in gardens can in part be attributed to the heterogeneity observed in this social environment. © 2011.


Kendal D.,Australian Research Center for Urban Ecology | Kendal D.,University of Melbourne | Williams N.S.G.,Australian Research Center for Urban Ecology | Williams N.S.G.,University of Melbourne | Williams K.J.H.,University of Melbourne
Urban Forestry and Urban Greening | Year: 2012

While we know that urban vegetation is often distributed unequally, most studies have been undertaken in cities with relatively high levels of income inequality, using a single measure of distribution (usually tree cover) and in a single land use. This study explores predictors of both tree cover and species richness in gardens, streetscapes and parks in Ballarat, Australia. Spatial regression models found that education level was a more important predictor of tree cover than household income across all land uses in Ballarat which can be explained by some people with high incomes relative to education level choosing to live in new residential developments with disproportionately low levels of tree cover. Inequality in tree cover was greater in streetscapes than in residential gardens, suggesting that 'top down' political factors are more important than individual behaviours in determining tree cover in Ballarat. In contrast, physical rather than socioeconomic factors were better predictors of species richness across all land uses, highlighting that different measures of vegetation distribution are not necessarily correlated. © 2012.


Forster M.A.,University of New South Wales | Ladd B.,Australian Research Center for Urban Ecology | Ladd B.,University of Melbourne | Bonser S.P.,University of New South Wales
Annals of Botany | Year: 2011

• Background and Aims: Heteroblasty is an encompassing term referring to ontogenetic changes in the plant shoot. A shaded environment is known to affect the process of heteroblastic development; however, it is not known whether crowded or high density growing conditions can also alter heteroblasty. Compound leaves of the shade-intolerant Acacia implexa allocate less biomass per unit photosynthetic area than transitional leaves or phyllodes and it is hypothesized that this trait will convey an advantage in a crowded environment. Compound leaves also have larger photosynthetic capture area - a trait known to be advantageous in shade. This studied tested the hypothesis that more compound leaves will be developed under shade and crowded environments. Furthermore, this species should undergo optimal allocation of biomass to shoots and roots given shaded and crowded environments. • Methods: A full factorial design of irradiance (high and low) and density levels (high, medium and low) on three populations sourced from varying rainfall regions (high, medium and low) was established under controlled glasshouse conditions. Traits measured include the number of nodes expressing a compound leaf, biomass allocation to shoots and roots, and growth traits. • Key Results: A higher number of nodes expressed a compound leaf under low irradiance and in high density treatments; however, there were no significant interactions across treatments. Phenotypes strongly associated with the shade avoidance syndrome were developed under low irradiance; however, this was not observed under high density. There was no significant difference in relative growth rates across light treatments, but growth was significantly slower in a crowded environment. • Conclusions: Heteroblastic development in Acacia can be altered by shade and crowded environments. In this experiment, light was clearly the most limiting factor to growth in a shaded environment; however, in a crowded environment there were additional limiting resources to growth. © The Author 2010. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.

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