Developing models of good practice in meeting the needs of homeless young people in rural areas

Andrew Beer, Paul Delfabbro, Susan Oakley, Fiona Verity, Kristin Natalier, Jasmin Packer and Alice Bas

Comparative population genetic structure of the endangered southern brown bandicoot, Isoodon obesulus, in fragmented landscapes of Southern Australia

Genetic connectivity is a key factor for maintaining the persistence of populations in fragmented landscapes. In highly modified landscapes such us peri-urban areas, organisms' dispersal among fragmented habitat patches can be reduced due to the surrounding matrix, leading to subsequent decreased gene flow and increased potential extinction risk in isolated sub-populations. However, few studies have compared within species how dispersal/gene flow varies between regions and among different forms of matrix that might be encountered. In the current study, we investigated gene flow and dispersal in an endangered marsupial, the southern brown bandicoot (Isoodon obesulus) in a heavily modified peri-urban landscape in South Australia, Australia. We used 14 microsatellite markers to genotype 254 individuals which were sampled from 15 sites. Analyses revealed significant genetic structure. Our analyses also indicated that dispersal was mostly limited to neighbouring sites. Comparisons of these results with analyses of a different population of the same species revealed that gene flow/dispersal was more limited in this peri-urban landscape than in a pine plantation landscape approximately 400 km to the south-east. These findings increase our understanding of how the nature of fragmentation can lead to profound differences in levels of genetic connectivity among populations of the same species.You Li, Steven J.B. Cooper, Melanie L. Lancaster, Jasmin G. Packer, Susan M. Carthe

Invasive non-native plants retain native mammal communities in novel ecosystems.

Biological invasions are a major threat to native ecosystems globally, yet in some landscapes they can also have important positive effects on native biodiversity. For example, invasive non-native plants have the potential to act as ecological engineers in novel ecosystems by ‘creating’ habitat where it is otherwise lacking, thereby increasing the diversity and abundance of native fauna. Yet little is known of their net effect on population persistence. Understanding the impact of non-native plants on native fauna is becoming increasingly urgent for conservation management, particularly in degraded and novel ecosystems where the broad-scale removal of weeds could threaten native fauna populations and the ecological processes they contribute to. This thesis takes a local and global view to investigate the conservation conundrum of native fauna responses to non-native plants. It examines the effect of non-native blackberry on individual, population and community-level responses of small native mammals in native, hybrid and novel ecosystems before proposing a multi-scale framework to quantify the net effect of non-native plants on native fauna persistence. The research was undertaken in the Mount Lofty Ranges of South Australia, a biodiversity hotspot that is considered a ‘canary landscape’ for temperate woodlands. The environmental decline seen here is expected to follow similar trends elsewhere. Blackberry (Rubus anglocandicans) is a non-native and highly invasive environmental weed that has been reported to provide habitat for native birds and mammals in the study region. The research was conducted as a multi-species study of small mammal responses to blackberry, with a particular focus on the nationally endangered southern brown bandicoot (Isoodon obesulus). Small mammal communities were surveyed for 11 consecutive seasons across 13 sites (7,500 ha) that represented native, hybrid and blackberry-dominated novel ecosystems of the region. A mixed modelling approach was used to quantify the net effect of blackberry on fauna responses at multiple scales, including: individual (reproduction and physiology); population (abundance, adult female density, and recruitment); and community (species richness, diversity and interspecific competition). To the best of knowledge, this is the first study on the impact of non-native plants on the recruitment and population persistence of native mammals. Ten species of small mammals, including six native, were captured across 12,235 captures and 31,407 trap sessions. Blackberry was identified as an ecological engineer in blackberry-dominated novel ecosystems, where it retains diverse native mammal communities of yellow-footed antechinus (Antechinus flavipes; vulnerable), bush rat (Rattus fuscipes), brushtail possum (Trichosurus vulpecula; rare), short-beaked echidna (Tachyglossus aculeatus) and southern brown bandicoot (Isoodon obesulus; endangered). The abundance, density, dispersal and recruitment of bandicoots were also greatest in blackberry, with arthropod abundance and blackberry density the strongest positive predictors for recruitment of juveniles from source populations into the overall meta-population. The results confirm that non-native plants can act as ecosystem engineers in novel ecosystems and create critical habitat that supports mammal communities where they would otherwise become locally extinct. Interactions between non-native and native species are increasing worldwide, and quantifying these complex dynamics is essential in order to successfully tackle the conservation challenges of the future. The final chapter of the thesis responds to this challenge by critiquing the traditional and emerging methods used in the empirical study, and synthesizing these with existing frameworks on non-native – native interactions. The thesis concludes by proposing two conceptual frameworks to: (1) inform future quantitative assessments of native fauna responses to non-native plants, and (2) guide restoration to retain positive ecosystem processes while reducing those that are harmful. Thus the research contributes to native fauna conservation in fragmented landscapes via both primary data collection for multiple species at multiple scales, and by suggesting frameworks to improve the effectiveness of restoration by prioritizing actions where non-native plants provide habitat for native fauna in degraded ecosystems.Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 201

Homelessness amongst young people in rural regions of Australia

Oxon, U

Native faunal communities depend on habitat from non-native plants in novel but not in natural ecosystems

Invasive non-native plants are a major driver of native biodiversity loss, yet native biodiversity can sometimes benefit from non-native species. Depending on habitat context, even the same non-native species can have positive and negative effects on biodiversity. Blackberry (Rubus fruticosus aggregate) is a useful model organism to better understand a non-native plant with conflicting impacts on biodiversity. We used a replicated capture-mark-recapture study across 11 consecutive seasons to examine the response of small mammal diversity and abundance to vegetation structure and density associated with non-native blackberry (R. anglocandicans) in native, hybrid and blackberry-dominated novel ecosystems in Australia. Across the three habitat types, increasing blackberry dominance had a positive influence on mammal diversity, while the strength and direction of this influence varied for abundance. At a microhabitat scale within hybrid and native habitat there were no significant differences in diversity, or the abundance of most species, between microhabitats where blackberry was absent versus dominant. In contrast, in novel ecosystems diversity and abundances were very low without blackberry, yet high (comparable to native ecosystems) within blackberry as it provided functionally-analogous vegetation structure and density to the lost native understory. Our results indicate the ecological functions of non-native plant species vary depending on habitat and need to be considered for management. Comparative studies such as ours that apply a standardized approach across a broad range of conditions at the landscape and habitat scale are crucial for guiding land managers on control options for non-native species (remove, reduce or retain and contain) that are context-sensitive and scale-dependent.ISSN:1572-9710ISSN:0960-311

Pairwise <i>F</i>_<i>ST</i> values (below diagonal) and pairwise <i>D</i>_<i>EST</i> values (above diagonal) estimated for the 15 sites sampled for <i>I</i>. <i>obesulus</i> (following Sequential Bonferroni correction).

<p>Pairwise <i>F</i>_<i>ST</i> values (below diagonal) and pairwise <i>D</i>_<i>EST</i> values (above diagonal) estimated for the 15 sites sampled for <i>I</i>. <i>obesulus</i> (following Sequential Bonferroni correction).</p

Correlograms showing genetic correlation (r) as a function of distance (0.5 km distance classes).

<p>The 95% confidence intervals (dashed lines) were determined by 1 000 permutations. Error bars of each estimate of r bound the 95% confidence intervals were determined by 1 000 bootstraps. (a) Whole data set; (b) Males only (n = 140) and (c) Females only (n = 105).</p

Results of migrants identified by STRUCTURE and GENECLASS analyses.

<p>Results of migrants identified by STRUCTURE and GENECLASS analyses.</p