• Energy Research

Geographic range size is often conceptualized as a fixed attribute of a species and treated as such for the purposes of quantification of extinction risk; species occupying smaller geographic ranges are assumed to have a higher risk of extinction, all else being equal. However many species are mobile, and their movements range from relatively predictable to-and-fro migrations to complex irregular movements shown by nomadic species. These movements can lead to substantial temporary expansion and contraction of geographic ranges, potentially to levels which may pose an extinction risk. By linking occurrence data with environmental conditions at the time of observations of nomadic species, we modeled the dynamic distributions of 43 arid-zone nomadic bird species across the Australian continent for each month over 11 years and calculated minimum range size and extent of fluctuation in geographic range size from these models. There was enormous variability in predicted spatial distribution over time; 10 species varied in estimated geographic range size by more than an order of magnitude, and 2 species varied by >2 orders of magnitude. During times of poor environmental conditions, several species not currently classified as globally threatened contracted their ranges to very small areas, despite their normally large geographic range size. This finding raises questions about the adequacy of conventional assessments of extinction risk based on static geographic range size (e.g., IUCN Red Listing). Climate change is predicted to affect the pattern of resource fluctuations across much of the southern hemisphere, where nomadism is the dominant form of animal movement, so it is critical we begin to understand the consequences of this for accurate threat assessment of nomadic species. Our approach provides a tool for discovering spatial dynamics in highly mobile species and can be used to unlock valuable information for improved extinction risk assessment and conservation planning.

Geographic range size is often conceptualized as a fixed attribute of a species and treated as such for the purposes of quantification of extinction risk; species occupying smaller geographic ranges are assumed to have a higher risk of extinction, all else being equal. However many species are mobile, and their movements range from relatively predictable to-and-fro migrations to complex irregular movements shown by nomadic species. These movements can lead to substantial temporary expansion and contraction of geographic ranges, potentially to levels which may pose an extinction risk. By linking occurrence data with environmental conditions at the time of observations of nomadic species, we modeled the dynamic distributions of 43 arid-zone nomadic bird species across the Australian continent for each month over 11 years and calculated minimum range size and extent of fluctuation in geographic range size from these models. There was enormous variability in predicted spatial distribution over time; 10 species varied in estimated geographic range size by more than an order of magnitude, and 2 species varied by >2 orders of magnitude. During times of poor environmental conditions, several species not currently classified as globally threatened contracted their ranges to very small areas, despite their normally large geographic range size. This finding raises questions about the adequacy of conventional assessments of extinction risk based on static geographic range size (e.g., IUCN Red Listing). Climate change is predicted to affect the pattern of resource fluctuations across much of the southern hemisphere, where nomadism is the dominant form of animal movement, so it is critical we begin to understand the consequences of this for accurate threat assessment of nomadic species. Our approach provides a tool for discovering spatial dynamics in highly mobile species and can be used to unlock valuable information for improved extinction risk assessment and conservation planning.

AbstractEcosystem management in the face of global change requires understanding how co‐occurring threats affect species and communities. Such an understanding allows for effective management strategies to be identified and implemented. An important component of this is differentiating between factors that are within (e.g. invasive predators) or outside (e.g. drought, large wildfires) of a local manager's control. In the global biodiversity hotspot of south‐western Australia, small‐ and medium‐sized mammal species are severely affected by anthropogenic threats and environmental disturbances, including invasive predators, fire, and declining rainfall. However, the relative importance of different drivers has not been quantified. We used data from a long‐term monitoring program to fit Bayesian state‐space models that estimated spatial and temporal changes in the relative abundance of four threatened mammal species: the woylie (Bettongia penicillata), chuditch (Dasyurus geoffroii), koomal (Trichosurus vulpecula) and quenda (Isoodon fusciventor). We then use Bayesian structural equation modelling to identify the direct and indirect drivers of population changes, and scenario analysis to forecast population responses to future environmental change. We found that habitat loss or conversion and reduced primary productivity (caused by rainfall declines) had greater effects on species' spatial and temporal population change than the range of fire and invasive predator (the red fox Vulpes vulpes) management actions observed in the study area. Scenario analysis revealed that a greater extent of severe fire and further rainfall declines predicted under climate change, operating in concert are likely to further reduce the abundance of these species, but may be mitigated partially by invasive predator control. Considering both historical and future drivers of population change is necessary to identify the factors that risk species recovery. Given that both anthropogenic pressures and environmental disturbances can undermine conservation efforts, managers must consider how the relative benefit of conservation actions will be shaped by ongoing global change.

AbstractEcosystem management in the face of global change requires understanding how co‐occurring threats affect species and communities. Such an understanding allows for effective management strategies to be identified and implemented. An important component of this is differentiating between factors that are within (e.g. invasive predators) or outside (e.g. drought, large wildfires) of a local manager's control. In the global biodiversity hotspot of south‐western Australia, small‐ and medium‐sized mammal species are severely affected by anthropogenic threats and environmental disturbances, including invasive predators, fire, and declining rainfall. However, the relative importance of different drivers has not been quantified. We used data from a long‐term monitoring program to fit Bayesian state‐space models that estimated spatial and temporal changes in the relative abundance of four threatened mammal species: the woylie (Bettongia penicillata), chuditch (Dasyurus geoffroii), koomal (Trichosurus vulpecula) and quenda (Isoodon fusciventor). We then use Bayesian structural equation modelling to identify the direct and indirect drivers of population changes, and scenario analysis to forecast population responses to future environmental change. We found that habitat loss or conversion and reduced primary productivity (caused by rainfall declines) had greater effects on species' spatial and temporal population change than the range of fire and invasive predator (the red fox Vulpes vulpes) management actions observed in the study area. Scenario analysis revealed that a greater extent of severe fire and further rainfall declines predicted under climate change, operating in concert are likely to further reduce the abundance of these species, but may be mitigated partially by invasive predator control. Considering both historical and future drivers of population change is necessary to identify the factors that risk species recovery. Given that both anthropogenic pressures and environmental disturbances can undermine conservation efforts, managers must consider how the relative benefit of conservation actions will be shaped by ongoing global change.

Global food supply has substantial impacts on nature including environmental degradation from chemicals, greenhouse gas emissions and biodiversity loss through agricultural land conversion. Over the past decade, public demand for information on sustainable consumption choices has increased. Meanwhile, development and expansion of the life cycle assessment literature has improved scientific evidence on supply chain impacts on the environment. However, data gaps and biases lead to uncertainty and undermine development of effective impact mitigation actions or behavior change policies. This study evaluates whether scientific research into the nature-related impacts of agri-food systems aligns with the needs of the public, as indicated by patterns of information seeking. We compare the relative volume of public Google queries to scientific articles related to agri-food systems and three major impacts: chemical pollution, greenhouse gas emissions or biodiversity loss. We discover that biodiversity is systematically overlooked in scientific studies on agri-food system impacts in favor of research on emissions and to a lesser extent chemical impacts. In contrast, total relative volumes of public queries on agri-food systems and biodiversity equal those for emissions impacts at global and Australian scales. Public interest in biodiversity impacts of agri-food systems increased significantly between 2009 and 2019, despite no significant change in the relative volume of biodiversity-focused scientific articles. Global public attention on chemical impacts declined significantly over this time period, with no significant change in the relative representation of this topic in scientific outputs. We recommend strategic investment into the biodiversity impacts of agri-food systems to build a knowledge base that allows the public to learn about the impacts of their choices and be inspired to change to more sustainable behaviors.

Global food supply has substantial impacts on nature including environmental degradation from chemicals, greenhouse gas emissions and biodiversity loss through agricultural land conversion. Over the past decade, public demand for information on sustainable consumption choices has increased. Meanwhile, development and expansion of the life cycle assessment literature has improved scientific evidence on supply chain impacts on the environment. However, data gaps and biases lead to uncertainty and undermine development of effective impact mitigation actions or behavior change policies. This study evaluates whether scientific research into the nature-related impacts of agri-food systems aligns with the needs of the public, as indicated by patterns of information seeking. We compare the relative volume of public Google queries to scientific articles related to agri-food systems and three major impacts: chemical pollution, greenhouse gas emissions or biodiversity loss. We discover that biodiversity is systematically overlooked in scientific studies on agri-food system impacts in favor of research on emissions and to a lesser extent chemical impacts. In contrast, total relative volumes of public queries on agri-food systems and biodiversity equal those for emissions impacts at global and Australian scales. Public interest in biodiversity impacts of agri-food systems increased significantly between 2009 and 2019, despite no significant change in the relative volume of biodiversity-focused scientific articles. Global public attention on chemical impacts declined significantly over this time period, with no significant change in the relative representation of this topic in scientific outputs. We recommend strategic investment into the biodiversity impacts of agri-food systems to build a knowledge base that allows the public to learn about the impacts of their choices and be inspired to change to more sustainable behaviors.

Fire is an ecologically important process in many habitats. Increases in the frequency and intensity of wildfires due to anthropogenic activity or future changes in the global climate are suspected to impact heavily on components of the biota in fire-dependent landscapes, but there is almost no knowledge of how changes to fire regimes interact with other stressors such as drying environments. We used livetrapping techniques to investigate the effects of wildfire and drought on the abundance of 3 species of small mammals in coastal woodland in southeastern Australia. We used a generalized linear mixed effects model design to compare 4 years of post-fire trapping results with pre-fire data on both burned and unburned sites. Numbers of all small mammal species were declining due to drought prior to an extensive wildfire. Wildfire significantly exacerbated the decline in abundance of small mammals in the year after fire. A return to wetter climatic conditions was accompanied by a recovery in small mammal numbers, which was faster in unburned sites than burned sites. Our results demonstrate a strong linkage between climatic conditions, fire, and mammal assemblages, and emphasize the need for long-term research to disentangle the interactive effects of these factors on wildlife.