Substantial long-term effects of carcass addition on soil and plants in a grassy eucalypt woodland
- Authors: Barton, Philip , McIntyre, Sue , Evans, Maldwyn , Bump, Joseph , Cunningham, Saul , Manning, Adrian
- Date: 2016
- Type: Text , Journal article
- Relation: Ecosphere Vol. 7, no. 10 (2016), p.
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- Description: The decomposition of large vertebrate carcasses generates small-scale disturbances characterized by changes in soil chemistry and new opportunities for plant establishment. Yet few studies have examined whether this effect is still evident several years after death, or has consequences for landscape-scale heterogeneity. We examined soil chemistry and plant species richness and composition at 12 kangaroo carcasses (~30 kg initial mass) five years after their initial placement. Each carcass was paired with a nearby "control" site for comparison. We found that soil phosphorus was eight times higher at carcasses than at control sites, but that nitrogen concentration was similar. We also found that plant composition was substantially different between each carcass and control pair, with 80% of carcasses dominated by exotic species (mostly weedy annuals). Notably, overall variability in plant species composition across carcass sites was not different from the variability at control sites, indicating that the colonization of carcasses by weedy species did not have a homogenizing effect on plant assemblages across our study landscape. Our study demonstrates that a localized effect of large vertebrate carcasses on soil and plants was still evident after five years, indicating a state shift in the soil-plant dynamics at a carcass site. However, the effect of carcasses on landscape-scale plant community heterogeneity was minimal because colonization was by weedy plants already present in the landscape. © 2016 Barton et al.
Direct and indirect effects of herbivore activity on Australian vegetation
- Authors: Eldridge, Davied , Travers, Samantha , Manning, Adrian , Barton, Philip
- Date: 2017
- Type: Text , Book chapter
- Relation: Australian vegetation p. 135-155
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Effects of ecological restoration on soil microbial diversity in a temperate grassy woodland
- Authors: Hamonts, Kelly , Bissett, Andrew , Macdonald, Ben , Barton, Philip , Manning, Adrian , Young, Andrew
- Date: 2017
- Type: Text , Journal article
- Relation: Applied Soil Ecology Vol. 117-118, no. (2017), p. 117-128
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- Description: Soil microbial communities are often overlooked in the context of ecological restoration. Given their central role in a broad range of ecosystem processes, however, understanding their response to restoration activities is critical to predicting restoration trajectories. In this study, we quantified the response of soil bacterial and fungal communities to restoration treatments, variation in microhabitat elements and vegetation in a critically endangered Australian box-gum grassy woodland ecosystem. Restoration treatments included the addition of coarse woody debris (CWD) and reduced grazing pressure. Four years after applying restoration treatments, we found no significant effect of CWD addition on soil microbial diversity, while reduced grazing significantly affected composition of the fungal, but not the bacterial, communities. Both bacterial and fungal communities responded to microhabitat element (open ground vs. old logs and trees), overlying vegetation and soil edaphic properties, and strong aboveground-belowground linkages were observed. Plant alpha diversity was positively correlated to soil bacterial, but not fungal, alpha diversity and plant community composition was a good predictor of both soil bacterial and fungal beta diversity. Co-occurrence network analysis identified numerous complex, non-linear associations between soil bacteria, fungi, edaphic properties and overlying plants. Soil microbes affected by restoration treatments included fungal saprotrophs and Actinobacteria, likely involved in litter breakdown, as well as bacteria likely involved in soil N cycling. Although the directions of the observed plant-microbe relationships remain unclear, we demonstrated the possibility of inducing changes to soil microbial communities to enhance restoration outcomes in box-gum grassy woodland ecosystems. © 2017 Elsevier B.V.
Environmental and spatial drivers of spider diversity at contrasting microhabitats
- Authors: Barton, Philip , Evans, Maldwyn , Foster, Claire , Cunningham, Saul , Manning, Adrian
- Date: 2017
- Type: Text , Journal article
- Relation: Austral Ecology Vol. 42, no. 6 (2017), p. 700-710
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- Description: The relative importance of environmental and spatial drivers of animal diversity varies across scales, but identifying these scales can be difficult if a sampling design does not match the scale of the target organisms' interaction with their habitat. In this study, we quantify and compare the effects of environmental variation and spatial proximity on ground-dwelling spider assemblages sampled from three distinct microhabitat types (open grassland, logs, trees) that recur across structurally heterogeneous grassy woodlands. We used model selection and multivariate procedures to compare the effects of different environmental attributes and spatial proximity on spider assemblages at each microhabitat type. We found that species richness and assemblage composition differed among microhabitat types. Bare ground cover had a negative effect on spider richness under trees, but a positive effect on spider richness in open grassland. Turnover in spider assemblages from open grassland was correlated with environmental distance, but not geographic distance. By contrast, turnover in spiders at logs and trees was correlated with geographic distance, but not environmental distance. Our study suggests that spider assemblages from widespread and connected open grassland habitat were more affected by environmental than spatial gradients, whereas spiders at log and tree habitats were more affected by spatial distance among these discrete but recurring microhabitats. Deliberate selection and sampling of small-scale habitat features can provide robust information about the drivers of arthropod diversity and turnover in landscapes. © 2017 Ecological Society of Australia
Fine-scale drivers of beetle diversity are affected by vegetation context and agricultural history
- Authors: Ross, Catherine , Barton, Philip , McIntyre, Sue , Cunningham, Saul , Manning, Adrian
- Date: 2017
- Type: Text , Journal article
- Relation: Austral Ecology Vol. 42, no. 7 (2017), p. 831-843
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- Description: Environmental gradients have been shown to affect animal diversity, but knowledge of fine-scale drivers of insect diversity is, in many cases, poorly developed. We investigated the drivers of beetle diversity and composition at different microhabitats, and how this may be mediated by past agricultural activities. The study was undertaken in temperate eucalypt grassy woodland near Canberra, south-eastern Australia, with a 200-year history of pastoral land use. We sampled beetles using pitfall traps at three microhabitats (open grassland, logs and under trees). We analysed the effects of soil properties, vegetation structure, and plant composition on beetle composition, and compared beetle responses among the microhabitats. We found that microhabitat was a strong determinant of the way beetle communities responded to their environment. Soil nutrients (C, N and P) were the strongest drivers of beetle species richness, abundance and composition at open and log microhabitat, however vegetation structure (tree basal area) was more important for beetle richness, abundance and biomass under trees. We also found significant differences in beetle composition among distinct ground-layer plant communities at log and tree microhabitat. We show that prior agricultural land use, particularly fertilization, has altered soil and plant communities, and that these effects continue to flow through the system affecting beetle assemblages. These findings have implications for future management of microhabitat structures in temperate grassy woodlands with a history of agricultural use. © 2017 Ecological Society of Australia
Beetle ecological indicators – A comparison of cost vs reward to understand functional changes in response to restoration actions
- Authors: Evans, Maldwyn , Cunningham, Saul , Gibb, Heloise , Manning, Adrian , Barton, Philip
- Date: 2019
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 104, no. (2019), p. 209-218
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- Description: Ecosystem restoration can play a vital role in conserving biodiversity, but its effectiveness can be difficult to assess for hyperdiverse biota such as insects. Species traits of insects can be used to understand their functional responses to restoration, but their use often requires considerable effort, and few studies have examined what additional insight can be gained from this approach. We used a spatially and temporally controlled restoration experiment to examine beetle species, grouped by flight ability, family membership and feeding guild, as indicators of ecosystem functional change. We tested for the effects of reduced vertebrate grazing on beetle assemblages sampled from two different microhabitats (next to log and in open ground)one year prior and two years after a vertebrate grazing treatment was applied. We compared the responses of the different beetle functional groupings, and then related these to the effort involved in employing these indicators. We found that beetle species traits gave several functional insights into their responses to reduced grazing, including responses to changes in vegetation structure and biomass. Species richness indicators and abundance indicators of beetle functional groups showed similar responses in many cases, whereas biomass indicators gave additional insights related to the extra biomass of vegetation and detritus resulting from the reduction in grazing. We found that most results were revealed by using family groups as indicators for functional change. This is because the traits that often define beetle families, such as size, flight ability and feeding guilds each have distinctive functional roles, allowing a link from family to function, and supporting the idea that phylogeny is often a useful shortcut to species ecology. We conclude that in our study system, the least-cost approach to identifying functional responses of beetles to reduced vertebrate grazing, and possibly other restoration actions, is to use abundance indicators of the most common family groups. © 2019 Elsevier Ltd
Outfoxing the fox : effect of prey odor on fox behavior in a pastoral landscape
- Authors: Andrewartha, Tim , Evans, Maldwyn , Batson, William , Manning, Adrian , Barton, Philip
- Date: 2021
- Type: Text , Journal article
- Relation: Conservation Science and Practice Vol. 3, no. 12 (2021), p.
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- Description: Invasive mammalian predators have had a devastating effect on native species globally. The European red fox (Vulpes vulpes) is one such species where it has been introduced in Australia. A novel but unexplored tactic to reduce the impact of mammalian predators is the use of unrewarded prey odors to undermine the effectiveness of olfactory hunting behavior. To test the viability of unrewarded prey odors in an applied setting we investigated how foxes responded to the odors of three different prey species. We used the odors of two locally extinct native Australian marsupials; the eastern quoll (a smaller carnivore) and eastern bettong (a fungivore), and the European rabbit, an introduced herbivore. Conducting our research over a period of 3 weeks in a pastoral environment in South-eastern Australia, we used video observations of foxes' behaviors, as they encountered the different odors. We found a reduction in the number of fox visits to bettong odors in the third week. In contrast, we observed a sustained number of visits to rabbit odors. Foxes also spent more time investigating rabbit odors and displayed longer durations of vigilance behavior at quoll odors. Our results support the hypothesis that the exposure of wild foxes to unrewarded odors of novel prey species can reduce their interest in these odors, which might translate to a reduction in predation pressure. Our results also suggest, however, that olfactory pre-exposure may not be as effective at reducing fox interest in a competitor species' odor. © 2021 The Authors. Conservation Science and Practice published by Wiley Periodicals LLC. on behalf of Society for Conservation Biology