Brendan Mackey

Re-evaluation of forest biomass carbon stocks and lessons from the world's most carbon-dense forests

From analysis of published global site biomass data (n = 136) from primary forests, we discovered (i) the worlds highest known total biomass carbon density (living plus dead) of 1,867 tonnes carbon per ha (average value from 13 sites) occurs in Australian temperate moist Eucalyptus regnans forests, and (ii) average values of the global site biomass data were higher for sampled temperate moist forests (n = 44) than for sampled tropical (n = 36) and boreal (n = 52) forests (n is number of sites per forest biome). Spatially averaged Intergovernmental Panel on Climate Change biome default values are lower than our average site values for temperate moist forests, because the temperate biome contains a diversity of forest ecosystem types that support a range of mature carbon stocks or have a long land-use history with reduced carbon stocks. We describe a framework for identifying forests important for carbon storage based on the factors that account for high biomass carbon densities, including (i) relatively cool temperatures and moderately high precipitation producing rates of fast growth but slow decomposition, and (ii) older forests that are often multiaged and multilayered and have experienced minimal human disturbance. Our results are relevant to negotiations under the United Nations Framework Convention on Climate Change regarding forest conservation, management, and restoration. Conserving forests with large stocks of biomass from deforestation and degradation avoids significant carbon emissions to the atmosphere, irrespective of the source country, and should be among allowable mitigation activities. Similarly, management that allows restoration of a forests carbon sequestration potential also should be recognized.

Incorporating ecological and evolutionary processes into continental‐scale conservation planning

Systematic conservation planning research has focused on designing systems of conservation areas that efficiently protect a comprehensive and representative set of species and habitats. Recently, there has been an emphasis on improving the adequacy of conservation area design to promote the persistence and future generation of biodiversity. Few studies have explored incorporating ecological and evolutionary processes into conservation planning assessments. Biodiversity in Australia is maintained and generated by numerous ecological and evolutionary processes at various spatial and temporal scales. We accommodated ecological and evolutionary processes in four ways: (1) using sub-catchments as planning units to facilitate the protection of the integrity and function of ecosystem processes occurring on a sub-catchment scale; (2) targeting one type of ecological refugia, drought refugia, which are critical for the persistence of many species during widespread drought; (3) targeting one type of evolutionary refugia which are important for maintaining and generating unique biota during long-term climatic changes; and (4) preferentially grouping priority areas along vegetated waterways to account for the importance of connected waterways and associated riparian areas in maintaining processes. We identified drought refugia, areas of relatively high and regular herbage production in arid and semiarid Australia, from estimates of gross primary productivity derived from satellite data. In this paper, we combined the novel incorporation of these processes with a more traditional framework of efficiently representing a comprehensive sample of biodiversity to identify spatial priorities across Australia. We explored the trade-offs between economic costs, representation targets, and connectivity. Priority areas that considered ecological and evolutionary processes were more connected along vegetated waterways and were identified for a small increase in economic cost. Priority areas for conservation investment are more likely to have long-term benefits to biodiversity if ecological and evolutionary processes are considered in their identification.

The Nature of Northern Australia: Natural Values, Ecological Processes and Future Prospects

The book offers a synthesis of the natural values and ecology of north Australia together with recommendations for actions needed to maintain these values. The book’s authors, John Woinarski (NRETA), Brendan Mackey (ANU), Henry Nix (ANU) and Barry Traill (Pugh Foundation, formerly The Wilderness Society) have brought together a great deal of recent research in these areas, much of it enabled by the TS–CRC partners, particularly through John Woinarski and NRETA.

Use of farm dams as frog habitat in an Australian agricultural landscape: factors affecting species richness and distribution

The terrestrial and aquatic attributes of 70 farm dams and five semi-natural waterbodies in the upper Shoalhaven catchment, south-eastern Australia, were examined. Relationships between habitat attributes, frog species richness and the presence of individual species were explored using mixed and logistic models. A positive relationship was found between the extent of native canopy cover in the surrounding landscape and frog species richness, and the occurrence of Litoria peronii and Uperoleia laevigata at farm dams. Annual mean temperature was negatively associated with the occurrence of L. peronii and L. verreauxii, but positively associated with Crinia parinsignifera. Extent of bare ground in the riparian zone and extent of emergent vegetation cover at the waters edge were also useful habitat predictors for several species. Results demonstrate that consideration must be given to both the aquatic and terrestrial environment to develop an understanding of factors influencing frog populations in modified environments and that these factors may vary from species to species. A comparison of species richness and individual models demonstrates that there are limitations associated with reliance upon species richness data to achieve conservation outcomes. Important habitat attributes of the environment may be masked at the species richness level as a result of contrasting responses between individual species.

Major conservation policy issues for biodiversity in oceania

Oceania is a diverse region encompassing Australia, Melanesia, Micronesia, New Zealand, and Polynesia, and it contains six of the worlds 39 hotspots of diversity. It has a poor record for extinctions, particularly for birds on islands and mammals. Major causes include habitat loss and degradation, invasive species, and overexploitation. We identified six major threatening processes (habitat loss and degradation, invasive species, climate change, overexploitation, pollution, and disease) based on a comprehensive review of the literature and for each developed a set of conservation policies. Many policies reflect the urgent need to deal with the effects of burgeoning human populations (expected to increase significantly in the region) on biodiversity. There is considerable difference in resources for conservation, including people and available scientific information, which are heavily biased toward more developed countries in Oceania. Most scientific publications analyzed for four threats (habitat loss, invasive species, overexploitation, and pollution) are from developed countries: 88.6% of Web of Science publications were from Australia (53.7%), New Zealand (24.3%), and Hawaiian Islands (10.5%). Many island states have limited resources or expertise. Even countries that do (e.g., Australia, New Zealand) have ongoing and emerging significant challenges, particularly with the interactive effects of climate change. Oceania will require the implementation of effective policies for conservation if the regions poor record on extinctions is not to continue.

The role of connectivity in Australian conservation

The existing system of nature reserves in Australia is inadequate for the long-term conservation and restoration of native biological diversity because it fails to accommodate, among other elements, large scale and long-term ecological processes and change, including physical and biotic transport in the landscape. This paper is an overview of the connectivity elements that inform a scientific framework for significantly improving the prospects for the long-term conservation of Australias biodiversity. The framework forms the basis for the WildCountry programme. This programme has identified connectivity at landscape, regional and continental scales as a critical component of an effective conservation system. Seven categories of ecological phenomena are reviewed that require landscape permeability and that must be considered when planning for the maintenance of biological diversity and ecological resilience in Australia: (1) trophic relations at regional scales; (2) animal migration, dispersal, and other large scale movements of individuals and propagules; (3) fire and other forms of disturbance at regional scales; (4) climate variability in space and time and human forced rapid climate change; (5) hydroecological relations and flows at all scales; (6) coastal zone fluxes of organisms, matter, and energy; and, (7) spatially-dependent evolutionary processes at all scales. Finally, we mention eight cross-cutting themes that further illuminate the interactions and implications of the seven connectivity-related phenomena for conservation assessment, planning, research, and management, and we suggest how the results might be applied by analysts, planners, scientists, and community conservationists.

Assessing representativeness of places for conservation reservation and heritage listing

Problems arising from application of the representative criterion for conservation and natural heritage evaluation are discussed. An ecological basis to this criterion is suggested that focuses on those key environmental factors dominating biotic response. A methodology is proposed that utilizes computer-based methods of establishing and interrogating spatial data bases (geographic information systems), environmental modeling, and numeric analysis. An example is presented illustrating some of the advantages and limitations of classification and dimension reduction techniques in both defining bioenvironments and displaying their spatial distribution. The advantages of this method for representativeness evaluation are that it maximizes the utility of available data, is explicit and repeatable, and enables large areas to be analyzed at relatively fine scales.

Assessing the representativeness of the wet tropics of Queensland world heritage property

Abstract An assessment is made of the representativeness of the Wet Tropics World Heritage property of north-east Queensland, Australia. The relevance of this feature to the World Heritage criteria is discussed. Computer-based spatial data sets are used to provide a sample of the distribution of key environmental factors at both continental and regional scales. Numerical classification techniques are applied to generate environmental groups from pattens in the distribution of these environmental factors. An evaluation is presented of the representation of these groups within the World Heritage property, in the context of present and potential tropical forest cover.

Improving the use of species distribution models in conservation planning and management under climate change

Choice of variables, climate models and emissions scenarios all influence the results of species distribution models under future climatic conditions. However, an overview of applied studies suggests that the uncertainty associated with these factors is not always appropriately incorporated or even considered. We examine the effects of choice of variables, climate models and emissions scenarios can have on future species distribution models using two endangered species: one a short-lived invertebrate species (Ptunarra Brown Butterfly), and the other a long-lived paleo-endemic tree species (King Billy Pine). We show the range in projected distributions that result from different variable selection, climate models and emissions scenarios. The extent to which results are affected by these choices depends on the characteristics of the species modelled, but they all have the potential to substantially alter conclusions about the impacts of climate change. We discuss implications for conservation planning and management, and provide recommendations to conservation practitioners on variable selection and accommodating uncertainty when using future climate projections in species distribution models.

Climate change, biodiversity conservation, and the role of protected areas: An Australian perspective

Abstract The reality of human-forced rapid climate change presents an unprecedented challenge to the conservation of biodiversity in Australia. In this paper we consider the role of Australias current protected area network in mitigating biodiversity loss across the continent. We do this by first examining the evolutionary history of Australias extant fauna and flora and, specifically, the reasons why species have persisted through major changes in climate during repeated glacial cycles, and through the massive climatic changes that occurred during the Miocene and Pliocene climate change events. We then review the current major threats to Australian native species, including inappropriate fire regimes, feral mammalian predators and herbivores, invasive plants, and habitat loss, fragmentation and degradation by land use activities (especially commercial logging, water impoundment and diversion, agricultural expansion, and the intensification of pastoralism). We argue that these current threats are interfering with the natural responses to climate change that native species have relied upon in the past, thereby undermining their resilience in the face of current, human-forced climate change. We predict that the current approach to conservation planning based on accumulating small amounts of protected lands across the continent, using a set of arbitrary conservation ‘targets’, will not be effective in mitigating the impacts of human-forced climate change on Australias biodiversity. We argue that an Australia-wide conservation strategy is needed that incorporates a larger adaptation agenda- one that recognizes the importance of protecting and restoring those natural processes and responses that have enabled species to persist through past environmental change. The following key elements are a crucial component of an effective conservation plan: identifying and protecting important climate refugia (both ecological and evolutionary); conserving the large-scale migration and connectivity corridors that operate at continent scales (including regional networks of habitat patches and habitat ‘stepping stones’); maintaining viable populations of all extant species to maximize intra-species genetic diversity and thus options for local adaptation; reducing all current threatening processes at the landscape scale across the continent; and protecting and restoring key large scale ecological processes (especially hydro-ecology and ecological fire regimes). Finally, underpinning climatic adaptation responses must be a thorough understanding of the special role Australias extensive intact landscapes will play in the future protection of Australias native biodiversity.