Effects of environmental variation and livestock grazing on ant community structure in temperate eucalypt woodlands
- Barton, Philip, Sato, Chloe, Kay, Geoffrey, Florance, Daniel, Lindenmayer, David
- Authors: Barton, Philip , Sato, Chloe , Kay, Geoffrey , Florance, Daniel , Lindenmayer, David
- Date: 2016
- Type: Text , Journal article
- Relation: Insect Conservation and Diversity Vol. 9, no. 2 (2016), p. 124-134
- Full Text:
- Reviewed:
- Description: Grazing by livestock is a major ecological disturbance, with potential effects on vegetation, soil, and insect fauna. Ants are a diverse and functionally important insect group with many associations with the ground layer, yet recent global syntheses question the importance of grazing effects on ant communities relative to vegetation or soil. We examined the effects of vegetation, soil and grazing on the whole ant community, ant functional groups, and abundant species in temperate eucalypt woodlands, southeastern Australia. We found limited influence of grazing on our vegetation and soil measures, except for a positive association between grazing and exotic perennial grass cover. We also found that exotic grass cover had a negative effect on overall ant abundance and richness, but not functional groups or individual species. Soil C:N ratio had a positive effect on the subdominant Camponotini, and leaf litter cover had a positive effect on the abundance of cryptic species. Partial Mantel tests revealed an effect of both environmental and grazing measures on ant assemblage composition, but constrained ordination showed that leaf litter cover, grass biomass, and native and exotic perennial grass cover had stronger correlations with ant community structure than grazing. Our study shows that both environmental variation and grazing play a role in driving ant community structure, but that key environmental variables such as grass biomass and leaf litter cover are particularly important in temperate eucalypt woodlands. Monitoring of ant communities to measure the benefits of changed grazing regimes for biodiversity should consider contemporary grazing pressure as well as the underlying effects of variation in plants and soils. © 2016 The Royal Entomological Society.
- Authors: Barton, Philip , Sato, Chloe , Kay, Geoffrey , Florance, Daniel , Lindenmayer, David
- Date: 2016
- Type: Text , Journal article
- Relation: Insect Conservation and Diversity Vol. 9, no. 2 (2016), p. 124-134
- Full Text:
- Reviewed:
- Description: Grazing by livestock is a major ecological disturbance, with potential effects on vegetation, soil, and insect fauna. Ants are a diverse and functionally important insect group with many associations with the ground layer, yet recent global syntheses question the importance of grazing effects on ant communities relative to vegetation or soil. We examined the effects of vegetation, soil and grazing on the whole ant community, ant functional groups, and abundant species in temperate eucalypt woodlands, southeastern Australia. We found limited influence of grazing on our vegetation and soil measures, except for a positive association between grazing and exotic perennial grass cover. We also found that exotic grass cover had a negative effect on overall ant abundance and richness, but not functional groups or individual species. Soil C:N ratio had a positive effect on the subdominant Camponotini, and leaf litter cover had a positive effect on the abundance of cryptic species. Partial Mantel tests revealed an effect of both environmental and grazing measures on ant assemblage composition, but constrained ordination showed that leaf litter cover, grass biomass, and native and exotic perennial grass cover had stronger correlations with ant community structure than grazing. Our study shows that both environmental variation and grazing play a role in driving ant community structure, but that key environmental variables such as grass biomass and leaf litter cover are particularly important in temperate eucalypt woodlands. Monitoring of ant communities to measure the benefits of changed grazing regimes for biodiversity should consider contemporary grazing pressure as well as the underlying effects of variation in plants and soils. © 2016 The Royal Entomological Society.
Evaluating the effectiveness of overstory cover as a surrogate for bird community diversity and population trends
- Pierson, Jennifer, Mortelliti, Alessio, Barton, Philip, Lane, Peter, Lindenmayer, David
- Authors: Pierson, Jennifer , Mortelliti, Alessio , Barton, Philip , Lane, Peter , Lindenmayer, David
- Date: 2016
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 61, no. (2016), p. 790-798
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- Description: Landscape features are often used as surrogates for biodiversity. While landscape features may perform well as surrogates for coarse metrics of biodiversity such as species richness, their value for monitoring population trends in individual species is virtually unexplored. We compared the performance of a proposed habitat surrogate for birds, percentage cover of vegetation overstory, for two distinct aspects of bird assemblages: community diversity (i.e. species richness) and population trends. We used four different long-term studies of open woodland habitats to test the consistency of the relationship between overstory percentage cover and bird species richness across a large spatial extent (>1000 km) in Australia. We then identified twelve bird species with long-term time-series data to test the relationship between change in overstory cover and populations trends. We found percentage cover performed consistently as a surrogate for species richness in three of the four sites. However, there was no clear pattern in the performance of change in percentage cover as a surrogate for population trends. Four bird species exhibited a significant relationship with change in percentage overstory cover in one study, but this was not found across multiple studies. These results demonstrate a lack of consistency in the relationship between change in overstory cover and population trends among bird species, both within and between geographic regions. Our study demonstrates that biodiversity surrogates representing community-level metrics may be consistent across regions, but provide only limited information about individual species population trends. Understanding the limitations of the information provided by a biodiversity surrogate can inform the appropriate context for its application. Crown Copyright © 2015 Published by Elsevier Ltd. All rights reserved.
- Authors: Pierson, Jennifer , Mortelliti, Alessio , Barton, Philip , Lane, Peter , Lindenmayer, David
- Date: 2016
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 61, no. (2016), p. 790-798
- Full Text:
- Reviewed:
- Description: Landscape features are often used as surrogates for biodiversity. While landscape features may perform well as surrogates for coarse metrics of biodiversity such as species richness, their value for monitoring population trends in individual species is virtually unexplored. We compared the performance of a proposed habitat surrogate for birds, percentage cover of vegetation overstory, for two distinct aspects of bird assemblages: community diversity (i.e. species richness) and population trends. We used four different long-term studies of open woodland habitats to test the consistency of the relationship between overstory percentage cover and bird species richness across a large spatial extent (>1000 km) in Australia. We then identified twelve bird species with long-term time-series data to test the relationship between change in overstory cover and populations trends. We found percentage cover performed consistently as a surrogate for species richness in three of the four sites. However, there was no clear pattern in the performance of change in percentage cover as a surrogate for population trends. Four bird species exhibited a significant relationship with change in percentage overstory cover in one study, but this was not found across multiple studies. These results demonstrate a lack of consistency in the relationship between change in overstory cover and population trends among bird species, both within and between geographic regions. Our study demonstrates that biodiversity surrogates representing community-level metrics may be consistent across regions, but provide only limited information about individual species population trends. Understanding the limitations of the information provided by a biodiversity surrogate can inform the appropriate context for its application. Crown Copyright © 2015 Published by Elsevier Ltd. All rights reserved.
Two roles for ecological surrogacy : indicator surrogates and management surrogates
- Hunter, Malcolm, Westgate, Martin, Barton, Philip, Calhoun, Aram, Pierson, Jennifer
- Authors: Hunter, Malcolm , Westgate, Martin , Barton, Philip , Calhoun, Aram , Pierson, Jennifer
- Date: 2016
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 63, no. (2016), p. 121-125
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- Reviewed:
- Description: Ecological surrogacy - here defined as using a process or element (e.g., species, ecosystem, or abiotic factor) to represent another aspect of an ecological system - is a widely used concept, but many applications of the surrogate concept have been controversial. We argue that some of this controversy reflects differences among users with different goals, a distinction that can be crystalized by recognizing two basic types of surrogate. First, many ecologists and natural resource managers measure "indicator surrogates" to provide information about ecological systems. Second, and often overlooked, are "management surrogates" (e.g., umbrella species) that are primarily used to facilitate achieving management goals, especially broad goals such as "maintain biodiversity" or "increase ecosystem resilience." We propose that distinguishing these two overarching roles for surrogacy may facilitate better communication about project goals. This is critical when evaluating the usefulness of different surrogates, especially where a potential surrogate might be useful in one role but not another. Our classification for ecological surrogacy applies to species, ecosystems, ecological processes, abiotic factors, and genetics, and thus can provide coherence across a broad range of uses. © 2015 Elsevier Ltd. All rights reserved. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton" is provided in this record**
- Authors: Hunter, Malcolm , Westgate, Martin , Barton, Philip , Calhoun, Aram , Pierson, Jennifer
- Date: 2016
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 63, no. (2016), p. 121-125
- Full Text:
- Reviewed:
- Description: Ecological surrogacy - here defined as using a process or element (e.g., species, ecosystem, or abiotic factor) to represent another aspect of an ecological system - is a widely used concept, but many applications of the surrogate concept have been controversial. We argue that some of this controversy reflects differences among users with different goals, a distinction that can be crystalized by recognizing two basic types of surrogate. First, many ecologists and natural resource managers measure "indicator surrogates" to provide information about ecological systems. Second, and often overlooked, are "management surrogates" (e.g., umbrella species) that are primarily used to facilitate achieving management goals, especially broad goals such as "maintain biodiversity" or "increase ecosystem resilience." We propose that distinguishing these two overarching roles for surrogacy may facilitate better communication about project goals. This is critical when evaluating the usefulness of different surrogates, especially where a potential surrogate might be useful in one role but not another. Our classification for ecological surrogacy applies to species, ecosystems, ecological processes, abiotic factors, and genetics, and thus can provide coherence across a broad range of uses. © 2015 Elsevier Ltd. All rights reserved. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton" is provided in this record**
Higher-taxon and functional group responses of ant and bird assemblages to livestock grazing : a test of an explicit surrogate concept
- Barton, Philip, Evans, Maldwyn, Sato, Chloe, O'Loughlin, Luke, Foster, Claire
- Authors: Barton, Philip , Evans, Maldwyn , Sato, Chloe , O'Loughlin, Luke , Foster, Claire
- Date: 2019
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 96, no. (2019), p. 458-465
- Full Text:
- Reviewed:
- Description: Biodiversity monitoring programs are routinely established to quantify changes in biotic communities in response to land management. Surrogacy is implicitly used in many such monitoring programs whereby the measurement of a component of biodiversity is used to infer responses of broader biodiversity. Yet rarely is this surrogacy validated by demonstrating that measured variables and the target variable of interest have matching responses to management treatments. Here we examined the responses of higher-taxon and functional groupings of ants and birds (our surrogate variables) two years after the implementation of experimental livestock grazing treatments, and compared these with the responses of total ant and bird species richness (our target variables) to the same treatments. We found significant and strong correlations between surrogate and target variables, but this did not predict corresponding similar response to treatments. For ants, we found that the genus Monomorium had a negative response to the grazing exclusion treatment, but there was no matching response of species richness, and so no surrogacy was identified. For birds, total species richness had a weak positive response to spring/summer grazing exclusion, and the abundance of honeyeaters (Meliphagidae) showed a similar positive response, suggesting surrogacy. Our study highlights that correlations among variables do not necessarily lead to surrogacy, and indeed that different sub-components of biotic assemblages can respond in ways that contrast with overall species richness. Careful assessment of the matched responses of surrogate and target variables to management can provide a simple and robust way to critically assess biodiversity surrogacy. © 2018 Elsevier Ltd. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton” is provided in this record**
- Authors: Barton, Philip , Evans, Maldwyn , Sato, Chloe , O'Loughlin, Luke , Foster, Claire
- Date: 2019
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 96, no. (2019), p. 458-465
- Full Text:
- Reviewed:
- Description: Biodiversity monitoring programs are routinely established to quantify changes in biotic communities in response to land management. Surrogacy is implicitly used in many such monitoring programs whereby the measurement of a component of biodiversity is used to infer responses of broader biodiversity. Yet rarely is this surrogacy validated by demonstrating that measured variables and the target variable of interest have matching responses to management treatments. Here we examined the responses of higher-taxon and functional groupings of ants and birds (our surrogate variables) two years after the implementation of experimental livestock grazing treatments, and compared these with the responses of total ant and bird species richness (our target variables) to the same treatments. We found significant and strong correlations between surrogate and target variables, but this did not predict corresponding similar response to treatments. For ants, we found that the genus Monomorium had a negative response to the grazing exclusion treatment, but there was no matching response of species richness, and so no surrogacy was identified. For birds, total species richness had a weak positive response to spring/summer grazing exclusion, and the abundance of honeyeaters (Meliphagidae) showed a similar positive response, suggesting surrogacy. Our study highlights that correlations among variables do not necessarily lead to surrogacy, and indeed that different sub-components of biotic assemblages can respond in ways that contrast with overall species richness. Careful assessment of the matched responses of surrogate and target variables to management can provide a simple and robust way to critically assess biodiversity surrogacy. © 2018 Elsevier Ltd. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton” is provided in this record**
How practitioners integrate decision triggers with existing metrics in conservation monitoring
- Foster, Claire, O'Loughlin, Luke, Sato, Chloe, Westgate, Martin, Barton, Philip
- Authors: Foster, Claire , O'Loughlin, Luke , Sato, Chloe , Westgate, Martin , Barton, Philip
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Environmental Management Vol. 230, no. (2019), p. 94-101
- Full Text:
- Reviewed:
- Description: Decision triggers are defined thresholds in the status of monitored variables that indicate when to undertake management, and avoid undesirable ecosystem change. Decision triggers are frequently recommended to conservation practitioners as a tool to facilitate evidence-based management practices, but there has been limited attention paid to how practitioners are integrating decision triggers into existing monitoring programs. We sought to understand whether conservation practitioners’ use of decision triggers was influenced by the type of variables in their monitoring programs. We investigated this question using a practitioner-focused workshop involving a structured discussion and review of eight monitoring programs. Among our case studies, direct measures of biodiversity (e.g. native species) were more commonly monitored, but less likely to be linked to decision triggers (10% with triggers) than measures being used as surrogates (54% with triggers) for program objectives. This was because decision triggers were associated with management of threatening processes, which were often monitored as a surrogate for a biodiversity asset of interest. By contrast, direct measures of biodiversity were more commonly associated with informal decision processes that led to activities such as management reviews or external consultation. Workshop participants were in favor of including more formalized decision triggers in their programs, but were limited by incomplete ecological knowledge, lack of appropriately skilled staff, funding constraints, and/or uncertainty regarding intervention effectiveness. We recommend that practitioners consider including decision triggers for discussion activities (such as external consultation) in their programs as more than just early warning points for future interventions, particularly for direct measures. Decision triggers for discussions should be recognized as a critical feature of monitoring programs where information and operational limitations inhibit the use of decision triggers for interventions. © 2018 Elsevier Ltd. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton” is provided in this record**
- Authors: Foster, Claire , O'Loughlin, Luke , Sato, Chloe , Westgate, Martin , Barton, Philip
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Environmental Management Vol. 230, no. (2019), p. 94-101
- Full Text:
- Reviewed:
- Description: Decision triggers are defined thresholds in the status of monitored variables that indicate when to undertake management, and avoid undesirable ecosystem change. Decision triggers are frequently recommended to conservation practitioners as a tool to facilitate evidence-based management practices, but there has been limited attention paid to how practitioners are integrating decision triggers into existing monitoring programs. We sought to understand whether conservation practitioners’ use of decision triggers was influenced by the type of variables in their monitoring programs. We investigated this question using a practitioner-focused workshop involving a structured discussion and review of eight monitoring programs. Among our case studies, direct measures of biodiversity (e.g. native species) were more commonly monitored, but less likely to be linked to decision triggers (10% with triggers) than measures being used as surrogates (54% with triggers) for program objectives. This was because decision triggers were associated with management of threatening processes, which were often monitored as a surrogate for a biodiversity asset of interest. By contrast, direct measures of biodiversity were more commonly associated with informal decision processes that led to activities such as management reviews or external consultation. Workshop participants were in favor of including more formalized decision triggers in their programs, but were limited by incomplete ecological knowledge, lack of appropriately skilled staff, funding constraints, and/or uncertainty regarding intervention effectiveness. We recommend that practitioners consider including decision triggers for discussion activities (such as external consultation) in their programs as more than just early warning points for future interventions, particularly for direct measures. Decision triggers for discussions should be recognized as a critical feature of monitoring programs where information and operational limitations inhibit the use of decision triggers for interventions. © 2018 Elsevier Ltd. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton” is provided in this record**
The use and utility of surrogates in biodiversity monitoring programmes
- Sato, Chloe, Westgate, Martin, Barton, Philip, Foster, Claire, O'Loughlin, Luke
- Authors: Sato, Chloe , Westgate, Martin , Barton, Philip , Foster, Claire , O'Loughlin, Luke
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Applied Ecology Vol. 56, no. 6 (2019), p. 1304-1310
- Full Text:
- Reviewed:
- Description: **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton” is provided in this record**
- Authors: Sato, Chloe , Westgate, Martin , Barton, Philip , Foster, Claire , O'Loughlin, Luke
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Applied Ecology Vol. 56, no. 6 (2019), p. 1304-1310
- Full Text:
- Reviewed:
- Description: **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton” is provided in this record**
Ant community responses to farmland use and revegetation in a fragmented agricultural landscape
- Ng, Katherine, Nowrouzi, Somayeh, Staunton, Kyran, Barton, Philip, Driscoll, Don
- Authors: Ng, Katherine , Nowrouzi, Somayeh , Staunton, Kyran , Barton, Philip , Driscoll, Don
- Date: 2021
- Type: Text , Journal article
- Relation: Agriculture Ecosystems & Environment Vol. 311, no. (May 2021), p. 8
- Full Text:
- Reviewed:
- Description: Recent alarming losses of insects from agricultural landscapes in multiple countries around the world have brought into sharp focus the urgent need to identify ways to manage these landscapes to avoid further biodiversity decline. Identifying the drivers of insect declines, such as land use change, is critical to this effort. We examined ant communities at the interface between remnant vegetation patches and three adjoining farmland types (wheat crop, rested from cropping and restoration plantings) in a fragmented landscape in temperate Australia. We asked: do ant communities and occurrence of individual species differ between remnant patches and farmlands with more intensive farmland use (restoration plantings < rested farmlands < wheat crop)? We recorded 13,283 ants belonging to 102 species from 30 genera. Excluding 21 singletons, 27 species only occurred in remnant patches compared to ten species found only in farmlands. Ant community composition in wheat crop and rested farmlands significantly differed from their adjacent remnant patches and were more homogeneous. In contrast, ant communities from restoration plantings in farmland were not significantly different in composition from those in the adjacent remnant patch. The large, aggressive Australian meat ant (Iridomyrmex purpureus) showed significantly higher occurrence in the remnant patch than all farmland types, and we suggest that the absence of this strongly interacting species from farmlands may have contributed to biotic homogenisation. Our findings show that native vegetation provides crucial habitat resources for many ant species that are not provided by farmlands, and native plantings can, in some cases, ameliorate negative effects of farmland clearing over relatively short time scales (<7 years). Agricultural intensification that involves loss of remnant native vegetation or reduced revegetation will contribute to ongoing losses and changes to ant biodiversity in farming landscapes. However, replanting native vegetation can lead to rapid restoration, signifying a possible simple remedy to insect declines.
- Authors: Ng, Katherine , Nowrouzi, Somayeh , Staunton, Kyran , Barton, Philip , Driscoll, Don
- Date: 2021
- Type: Text , Journal article
- Relation: Agriculture Ecosystems & Environment Vol. 311, no. (May 2021), p. 8
- Full Text:
- Reviewed:
- Description: Recent alarming losses of insects from agricultural landscapes in multiple countries around the world have brought into sharp focus the urgent need to identify ways to manage these landscapes to avoid further biodiversity decline. Identifying the drivers of insect declines, such as land use change, is critical to this effort. We examined ant communities at the interface between remnant vegetation patches and three adjoining farmland types (wheat crop, rested from cropping and restoration plantings) in a fragmented landscape in temperate Australia. We asked: do ant communities and occurrence of individual species differ between remnant patches and farmlands with more intensive farmland use (restoration plantings < rested farmlands < wheat crop)? We recorded 13,283 ants belonging to 102 species from 30 genera. Excluding 21 singletons, 27 species only occurred in remnant patches compared to ten species found only in farmlands. Ant community composition in wheat crop and rested farmlands significantly differed from their adjacent remnant patches and were more homogeneous. In contrast, ant communities from restoration plantings in farmland were not significantly different in composition from those in the adjacent remnant patch. The large, aggressive Australian meat ant (Iridomyrmex purpureus) showed significantly higher occurrence in the remnant patch than all farmland types, and we suggest that the absence of this strongly interacting species from farmlands may have contributed to biotic homogenisation. Our findings show that native vegetation provides crucial habitat resources for many ant species that are not provided by farmlands, and native plantings can, in some cases, ameliorate negative effects of farmland clearing over relatively short time scales (<7 years). Agricultural intensification that involves loss of remnant native vegetation or reduced revegetation will contribute to ongoing losses and changes to ant biodiversity in farming landscapes. However, replanting native vegetation can lead to rapid restoration, signifying a possible simple remedy to insect declines.
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