Agricultural expansion and intensification is a major threat to biodiversity globally, yet agricu... more Agricultural expansion and intensification is a major threat to biodiversity globally, yet agricultural landscapes often support complex and dynamic biological communities within a diverse array of land uses. To examine the relative biodiversity value of land uses ranging from low to ...
Conservation biology : the journal of the Society for Conservation Biology, Jan 21, 2015
Recognising that protected areas (PAs) are essential for effective biodiversity conservation acti... more Recognising that protected areas (PAs) are essential for effective biodiversity conservation action, the Convention on Biological Diversity established ambitious PA targets as part of the 2020 Strategic Plan for Biodiversity. Under the strategic goal to "improve the status of biodiversity by safeguarding ecosystems, species and genetic diversity", Target 11 aims to put 17% of terrestrial and 10% of marine regions under PA status by 2020. Additionally and crucially, these areas are required to be of particular importance for biodiversity and ecosystem services, effectively and equitably managed, ecologically representative and well connected, and to include "other effective area-based conservation measures" (OECMs). While the area-based targets are explicit and measurable, the lack of guidance for what (i) "important" and "representative"; (ii) "effective"; and (iii) OECMs means is affecting how nations are implementing the target. Th...
... Managing tradeoffs in landscape restoration and revegetation projects. Ecological Application... more ... Managing tradeoffs in landscape restoration and revegetation projects. Ecological Applications 18, 20412049. Maron, M., Dunn, PK, McAlpine, CA and Apan, A.(2010). Can offsets really compensate for habitat removal? The case of the endangered red-tailed black-cockatoo. ...
A palaeoclimatic Holocene rainfall history is reported for Lake Broadwater in southeast Queenslan... more A palaeoclimatic Holocene rainfall history is reported for Lake Broadwater in southeast Queensland, Australia. This naturally-occurring semi-permanent freshwater lake is part of the Condamine-Balonne Catchment on the Darling Downs. It is an important natural habitat for waterbirds and other wildlife, but it dried-out completely during the Australian Millennium Drought. Lake sediments were sampled to a depth of about 1.7 m from the centre of the lake in March 2007. A detailed chronology developed from radiocarbon (14C) dating indicates that sedimentation was fairly constant into the lake and averaged ~0.16 mm year-1 since about 11 kyr cal B.P. An interpretation of the palaeoclimatic record indicates higher rainfall and moist conditions prevailed from ~11 kyr to ~3.5 kyr cal B.P., followed by lower rainfall, decreasing further from ~2.2 kyr cal B.P to the present day. This change to drier conditions most likely reflects an increase in El Niño–Southern Oscillation (ENSO) cycles which b...
Matrix land-use intensification is a relatively recent and novel landscape change that can have i... more Matrix land-use intensification is a relatively recent and novel landscape change that can have important influences on the biota within adjacent habitat patches. While there are immediate local changes that it brings about, the influences on individual animals occupying adjacent habitats may be less evident initially. High-intensity land use could induce chronic stress in individuals in nearby remnants, leading ultimately to population declines. We investigated how physiological indicators and body condition measures of tropical forest-dependent birds differ between forest adjacent to surface mining sites and that near farmlands at two distances from remnant edge in southwest Ghana. We used mixed effects models of several condition indices including residual body mass and heterophil to lymphocyte (H/L) ratios (an indicator of elevated chronic stress) to explore the effect of matrix intensity on forest-dependent passerines classed as either sedentary area-sensitive habitat specialis...
Resource bottlenecks—periods of severe restriction in resource availability—triggered by increase... more Resource bottlenecks—periods of severe restriction in resource availability—triggered by increased climate variability represent important and little-understood mechanisms through which climate change will affect biodiversity. In this review, we aim to synthesise the key global change processes that exacerbate the severity of bottlenecks in resource availability on animal populations, and outline how adaptation responses can help buffer the impacts. We collate examples from the literature of population-level impacts of resource bottlenecks induced by extreme weather and climate events to explore the types of population impacts that have most frequently been recorded and the type of extreme events associated with them. We then develop a conceptual framework that captures the factors contributing to species’ vulnerability to climate-induced spatial and temporal resource bottlenecks in increasingly variable environments. Increases in the frequency, severity and/or duration of extreme weather and climate events can trigger resource bottlenecks that act as powerful demographic constraints on terrestrial fauna, and often exacerbate other human-induced pressures such as land use change. Such phenomena are likely to become more frequent and severe, with potentially nonlinear increases in impact. Forty-nine instances of population-level impacts from climate-induced resource bottlenecks were recorded from the literature, including four extinctions and ten population crashes. Anthropogenic land use change interacts with increasing climatic variability to exacerbate these resource ‘crunches’, but can sometimes act as a buffer for species. Resource bottlenecks are likely to be a large class of climate-sensitive stressors whose impacts may play out at the population scale, even well within a species’ apparent climatic envelope. More effective conservation responses to climate-related threats include explicit actions, such as managing protected area networks for spatial and temporal resource complementarity, that buffer vulnerable species against bottlenecks.
ABSTRACT Forest use practices such as logging, lopping of tree branches for fodder, and grazing d... more ABSTRACT Forest use practices such as logging, lopping of tree branches for fodder, and grazing do not reduce forest area but disturb forest structure and impact biodiversity. Although such forest disturbances can be key determinants of the biota occupying a site, rarely is the interaction between disturbance intensity and landscape context considered, despite its relevance to conservation management. We investigated the influence of site-and landscape-level habitat characteristics on birds, and explored whether the effects of site-level disturbance on bird richness varied with forest extent in lowland landscapes in Nepal. While extractive uses reduced forest structural complexity and altered the avifaunal community of a site, the intensity of such effects depended on the extent of forest in the surrounding landscape (19.6 km2). The extent of forest, large tree density, and tree canopy cover were important predictors for all bird response groups. However, the effect of forest extent on bird richness was stronger for sites with greater disturbance intensity. Managing and restoring landscapes to support greater forest cover may not only have a positive direct effect on bird conservation, but may also help to compensate for site-level disturbance, such as characterises multiple-use forests worldwide.
ABSTRACT Context. Large reserves have potential to provide important refugia for fragmentation-se... more ABSTRACT Context. Large reserves have potential to provide important refugia for fragmentation-sensitive species as they lack many aspects of habitat degradation associated with fragmented regions. However, large reserves often have a history of deleterious management practices that may affect the restoration of biological diversity. One significant symptom of habitat fragmentation and disturbance in Australia is the increased occurrence of the aggressive noisy miner (Manorina melanocephala). In Queensland, however, even large continuous areas of woodland appear to be dominated by the noisy miner. Aims.We examined the severity of this phenomenon by identifying the interactions between habitat structure, noisy miner abundance and avian assemblages in a private and a public conservation reserve in central Queensland. We investigated potential constraints on restoration of avian diversity including: (1) how changes in habitat structure as a result of grazing by feral animals and burning regimes affect bird assemblages; and (2) how the noisy miner impacts on avian assemblages in these unfragmented woodlands. Methods. Bird surveys and habitat assessments were conducted in 49 sites on three separate occasions. Fire history and intensity of grazing pressure were determined for each site with direct and indirect observations. Sampling for lerp from insects of the family Psyllidae was also undertaken during the survey periods. A Bayesian model averaging (BMA) approach was used to model avian response to each of the habitat variables. Key results. The noisy miner dominated most of the study area, reducing small passerine abundance and species richness. Noisy miners were advantaged where shrub cover was low and feral grazing impacts were evident. Disturbance factors including recent wildfire and heavy grazing strongly reduced small passerine bird richness and abundance. Conclusions. Reducing the abundance of this 'reverse keystone' species requires control of feral herbivore populations and modification of fire regimes to achieve a mosaic including patches with a dense shrub layer. Implications. Deleterious interactions with competitive native species, such as noisy miners, are obstacles to bird conservation not only in fragmented landscapes but also in large, continuous woodland areas. Land mangers of protected areas need to be aware of shifts in interactions among native species driven by habitat disturbance, which may ultimately affect conservation outcomes.
Agricultural expansion and intensification is a major threat to biodiversity globally, yet agricu... more Agricultural expansion and intensification is a major threat to biodiversity globally, yet agricultural landscapes often support complex and dynamic biological communities within a diverse array of land uses. To examine the relative biodiversity value of land uses ranging from low to ...
Conservation biology : the journal of the Society for Conservation Biology, Jan 21, 2015
Recognising that protected areas (PAs) are essential for effective biodiversity conservation acti... more Recognising that protected areas (PAs) are essential for effective biodiversity conservation action, the Convention on Biological Diversity established ambitious PA targets as part of the 2020 Strategic Plan for Biodiversity. Under the strategic goal to "improve the status of biodiversity by safeguarding ecosystems, species and genetic diversity", Target 11 aims to put 17% of terrestrial and 10% of marine regions under PA status by 2020. Additionally and crucially, these areas are required to be of particular importance for biodiversity and ecosystem services, effectively and equitably managed, ecologically representative and well connected, and to include "other effective area-based conservation measures" (OECMs). While the area-based targets are explicit and measurable, the lack of guidance for what (i) "important" and "representative"; (ii) "effective"; and (iii) OECMs means is affecting how nations are implementing the target. Th...
... Managing tradeoffs in landscape restoration and revegetation projects. Ecological Application... more ... Managing tradeoffs in landscape restoration and revegetation projects. Ecological Applications 18, 20412049. Maron, M., Dunn, PK, McAlpine, CA and Apan, A.(2010). Can offsets really compensate for habitat removal? The case of the endangered red-tailed black-cockatoo. ...
A palaeoclimatic Holocene rainfall history is reported for Lake Broadwater in southeast Queenslan... more A palaeoclimatic Holocene rainfall history is reported for Lake Broadwater in southeast Queensland, Australia. This naturally-occurring semi-permanent freshwater lake is part of the Condamine-Balonne Catchment on the Darling Downs. It is an important natural habitat for waterbirds and other wildlife, but it dried-out completely during the Australian Millennium Drought. Lake sediments were sampled to a depth of about 1.7 m from the centre of the lake in March 2007. A detailed chronology developed from radiocarbon (14C) dating indicates that sedimentation was fairly constant into the lake and averaged ~0.16 mm year-1 since about 11 kyr cal B.P. An interpretation of the palaeoclimatic record indicates higher rainfall and moist conditions prevailed from ~11 kyr to ~3.5 kyr cal B.P., followed by lower rainfall, decreasing further from ~2.2 kyr cal B.P to the present day. This change to drier conditions most likely reflects an increase in El Niño–Southern Oscillation (ENSO) cycles which b...
Matrix land-use intensification is a relatively recent and novel landscape change that can have i... more Matrix land-use intensification is a relatively recent and novel landscape change that can have important influences on the biota within adjacent habitat patches. While there are immediate local changes that it brings about, the influences on individual animals occupying adjacent habitats may be less evident initially. High-intensity land use could induce chronic stress in individuals in nearby remnants, leading ultimately to population declines. We investigated how physiological indicators and body condition measures of tropical forest-dependent birds differ between forest adjacent to surface mining sites and that near farmlands at two distances from remnant edge in southwest Ghana. We used mixed effects models of several condition indices including residual body mass and heterophil to lymphocyte (H/L) ratios (an indicator of elevated chronic stress) to explore the effect of matrix intensity on forest-dependent passerines classed as either sedentary area-sensitive habitat specialis...
Resource bottlenecks—periods of severe restriction in resource availability—triggered by increase... more Resource bottlenecks—periods of severe restriction in resource availability—triggered by increased climate variability represent important and little-understood mechanisms through which climate change will affect biodiversity. In this review, we aim to synthesise the key global change processes that exacerbate the severity of bottlenecks in resource availability on animal populations, and outline how adaptation responses can help buffer the impacts. We collate examples from the literature of population-level impacts of resource bottlenecks induced by extreme weather and climate events to explore the types of population impacts that have most frequently been recorded and the type of extreme events associated with them. We then develop a conceptual framework that captures the factors contributing to species’ vulnerability to climate-induced spatial and temporal resource bottlenecks in increasingly variable environments. Increases in the frequency, severity and/or duration of extreme weather and climate events can trigger resource bottlenecks that act as powerful demographic constraints on terrestrial fauna, and often exacerbate other human-induced pressures such as land use change. Such phenomena are likely to become more frequent and severe, with potentially nonlinear increases in impact. Forty-nine instances of population-level impacts from climate-induced resource bottlenecks were recorded from the literature, including four extinctions and ten population crashes. Anthropogenic land use change interacts with increasing climatic variability to exacerbate these resource ‘crunches’, but can sometimes act as a buffer for species. Resource bottlenecks are likely to be a large class of climate-sensitive stressors whose impacts may play out at the population scale, even well within a species’ apparent climatic envelope. More effective conservation responses to climate-related threats include explicit actions, such as managing protected area networks for spatial and temporal resource complementarity, that buffer vulnerable species against bottlenecks.
ABSTRACT Forest use practices such as logging, lopping of tree branches for fodder, and grazing d... more ABSTRACT Forest use practices such as logging, lopping of tree branches for fodder, and grazing do not reduce forest area but disturb forest structure and impact biodiversity. Although such forest disturbances can be key determinants of the biota occupying a site, rarely is the interaction between disturbance intensity and landscape context considered, despite its relevance to conservation management. We investigated the influence of site-and landscape-level habitat characteristics on birds, and explored whether the effects of site-level disturbance on bird richness varied with forest extent in lowland landscapes in Nepal. While extractive uses reduced forest structural complexity and altered the avifaunal community of a site, the intensity of such effects depended on the extent of forest in the surrounding landscape (19.6 km2). The extent of forest, large tree density, and tree canopy cover were important predictors for all bird response groups. However, the effect of forest extent on bird richness was stronger for sites with greater disturbance intensity. Managing and restoring landscapes to support greater forest cover may not only have a positive direct effect on bird conservation, but may also help to compensate for site-level disturbance, such as characterises multiple-use forests worldwide.
ABSTRACT Context. Large reserves have potential to provide important refugia for fragmentation-se... more ABSTRACT Context. Large reserves have potential to provide important refugia for fragmentation-sensitive species as they lack many aspects of habitat degradation associated with fragmented regions. However, large reserves often have a history of deleterious management practices that may affect the restoration of biological diversity. One significant symptom of habitat fragmentation and disturbance in Australia is the increased occurrence of the aggressive noisy miner (Manorina melanocephala). In Queensland, however, even large continuous areas of woodland appear to be dominated by the noisy miner. Aims.We examined the severity of this phenomenon by identifying the interactions between habitat structure, noisy miner abundance and avian assemblages in a private and a public conservation reserve in central Queensland. We investigated potential constraints on restoration of avian diversity including: (1) how changes in habitat structure as a result of grazing by feral animals and burning regimes affect bird assemblages; and (2) how the noisy miner impacts on avian assemblages in these unfragmented woodlands. Methods. Bird surveys and habitat assessments were conducted in 49 sites on three separate occasions. Fire history and intensity of grazing pressure were determined for each site with direct and indirect observations. Sampling for lerp from insects of the family Psyllidae was also undertaken during the survey periods. A Bayesian model averaging (BMA) approach was used to model avian response to each of the habitat variables. Key results. The noisy miner dominated most of the study area, reducing small passerine abundance and species richness. Noisy miners were advantaged where shrub cover was low and feral grazing impacts were evident. Disturbance factors including recent wildfire and heavy grazing strongly reduced small passerine bird richness and abundance. Conclusions. Reducing the abundance of this 'reverse keystone' species requires control of feral herbivore populations and modification of fire regimes to achieve a mosaic including patches with a dense shrub layer. Implications. Deleterious interactions with competitive native species, such as noisy miners, are obstacles to bird conservation not only in fragmented landscapes but also in large, continuous woodland areas. Land mangers of protected areas need to be aware of shifts in interactions among native species driven by habitat disturbance, which may ultimately affect conservation outcomes.
Uploads
Papers by Martine Maron
Resource bottlenecks are likely to be a large class of climate-sensitive stressors whose impacts may play out at the population scale, even well within a species’ apparent climatic envelope. More effective conservation responses to climate-related threats include explicit actions, such as managing protected area networks for spatial and temporal resource complementarity, that buffer vulnerable species against bottlenecks.
Resource bottlenecks are likely to be a large class of climate-sensitive stressors whose impacts may play out at the population scale, even well within a species’ apparent climatic envelope. More effective conservation responses to climate-related threats include explicit actions, such as managing protected area networks for spatial and temporal resource complementarity, that buffer vulnerable species against bottlenecks.