Grant Wardell-Johnson

Conserving biodiversity efficiently: What to Do, Where, and When

Conservation priority-setting schemes have not yet combined geographic priorities with a framework that can guide the allocation of funds among alternate conservation actions that address specific threats. We develop such a framework, and apply it to 17 of the worlds 39 Mediterranean ecoregions. This framework offers an improvement over approaches that only focus on land purchase or species richness and do not account for threats. We discover that one could protect many more plant and vertebrate species by investing in a sequence of conservation actions targeted towards specific threats, such as invasive species control, land acquisition, and off-reserve management, than by relying solely on acquiring land for protected areas. Applying this new framework will ensure investment in actions that provide the most cost-effective outcomes for biodiversity conservation. This will help to minimise the misallocation of scarce conservation resources.

The capacity of refugia for conservation planning under climate change

Refugia – areas that may facilitate the persistence of species during large-scale, long-term climatic change –are increasingly important for conservation planning. There are many methods for identifying refugia, but the ability to quantify their potential for facilitating species persistence (ie their “capacity”) remains elusive. We propose a flexible framework for prioritizing future refugia, based on their capacity. This framework can be applied through various modeling approaches and consists of three steps: (1) definition of scope, scale, and resolution; (2) identification and quantification; and (3) prioritization for conservation. Capacity is quantified by multiple indicators, including environmental stability, microclimatic heterogeneity, size, and accessibility of the refugium. Using an integrated, semi-mechanistic modeling technique, we illustrate how this approach can be implemented to identify refugia for the plant diversity of Tasmania, Australia. The highest-capacity climate-change refugia we...

Landscape age and soil fertility, climatic stability, and fire regime predictability: Beyond the OCBIL framework

Hopper (Plant Soil 322:49–86, 2009) introduced landscape age, climate buffering, and soil nutrient status as descriptors for a continuum between old, climatically buffered landscapes characterised by low soil fertility (OCBIL) and young, often disturbed landscapes characterised by fertile soils (YODFEL). Hopper (Plant Soil 322:49–86, 2009) provided an important framework for biodiversity and conservation. We argue that Hopper’s (Plant Soil 322:49–86, 2009) conceptual framework includes five areas worthy of further consideration. These include: (1) The appropriateness of the original three dimensions; (2) The need for deeper consideration of rejuvenation and disturbance within OCBILs. (3) Broadening the globally relevant range of environments. (4) Operationalising the definitions or dimensions. (5) Revisiting the scale and compatibility of the predictions. Here, we address the first four of these areas and offer an alternative conceptual framework based on the idea of Old Stable Landscapes (OSLs). We redefine Hopper’s climate buffering as a dimension of climate stability, identify soil-impoverishment as a function of landscape age, and recognise fire regime predictability as a large-scale, long-term evolutionarily important dimension. In so doing, we construct a globally-relevant, qualitative template to enable the testing of evolutionary-ecological hypotheses concerning biodiversity (e.g. species diversity, diversity gradients, endemism, speciation and extinction rates, cladogenesis, persistence of old lineages, refugial phenomena). Our template is characterised by having operationally defined dimensions, which can be used to design surveys and experiments to address the issues of biodiversity conservation, recovery, and restoration under variations in landscape age, climatic stability and fire regime.

Old-growth forests, carbon and climate change: Functions and management for tall open-forests in two hotspots of temperate Australia

Abstract The prognosis and utility under climate change are presented for two old‐growth, temperate forests in Australia, from ecological and carbon accounting perspectives. The tall open‐forests (TOFs) of south‐western Australia (SWA) are within Australia’s global biodiversity hotspot. The forest management and timber usage from the carbon‐dense old‐growth TOFs of Tasmania (TAS) have a high carbon efflux, rendering it a carbon hotspot. Under climate change the warmer, dryer climate in both areas will decrease carbon stocks directly; and indirectly through changes towards dryer forest types and through positive feedback. Near 2100, climate change will decrease soil organic carbon (SOC) significantly, e.g. by ∼30% for SWA and at least 2% for TAS. The emissions from the next 20 years of logging old‐growth TOF in TAS, and conversion to harvesting cycles, will conservatively reach 66(±33) Mt‐CO2‐equivalents in the long‐term – bolstering greenhouse gas emissions. Similar emissions will arise from rainforest SOC in TAS due to climate change. Careful management of old‐growth TOFs in these two hotspots, to help reduce carbon emissions and change in biodiversity, entails adopting approaches to forest, wood product and fire management which conserve old‐growth characteristics in forest stands. Plantation forestry on long‐cleared land and well‐targeted prescribed burning supplement effective carbon management. Abbreviations: C, carbon; CBS, clearfell, burn and sow; CO2‐e, CO2 equivalents; CWD, coarse woody debris; DOC, dissolved organic carbon; GHG, greenhouse gas; Mt, megatonnes; SOC, soil organic carbon; SWA, south‐western Australia; SWAFR, Southwest Australian Floristic Region; TAS, Tasmania; TOF, tall open‐forest; t‐C ha−1 yr−1, tonnes of carbon per hectare per year

What makes a journal international? A case study using conservation biology journals

The qualitative label ‘international journal’ is used widely, including in national research quality assessments. We determined the practicability of analysing internationality quantitatively using 39 conservation biology journals, providing a single numeric index (IIJ) based on 10 variables covering the countries represented in the journals’ editorial boards, authors and authors citing the journals’ papers. A numerical taxonomic analysis refined the interpretation, revealing six categories of journals reflecting distinct international emphases not apparent from simple inspection of the IIJs alone. Categories correlated significantly with journals’ citation impact (measured by the Hirsch index), with their rankings under the Australian Commonwealth’s ‘Excellence in Research for Australia’ and with some countries of publication, but not with listing by ISI Web of Science. The assessments do not reflect on quality, but may aid editors planning distinctive journal profiles, or authors seeking appropriate outlets.

Rapid Characterisation of Vegetation Structure to Predict Refugia and Climate Change Impacts across a Global Biodiversity Hotspot

Identification of refugia is an increasingly important adaptation strategy in conservation planning under rapid anthropogenic climate change. Granite outcrops (GOs) provide extraordinary diversity, including a wide range of taxa, vegetation types and habitats in the Southwest Australian Floristic Region (SWAFR). However, poor characterization of GOs limits the capacity of conservation planning for refugia under climate change. A novel means for the rapid identification of potential refugia is presented, based on the assessment of local-scale environment and vegetation structure in a wider region. This approach was tested on GOs across the SWAFR. Airborne discrete return Light Detection And Ranging (LiDAR) data and Red Green and Blue (RGB) imagery were acquired. Vertical vegetation profiles were used to derive 54 structural classes. Structural vegetation types were described in three areas for supervised classification of a further 13 GOs across the region. Habitat descriptions based on 494 vegetation plots on and around these GOs were used to quantify relationships between environmental variables, ground cover and canopy height. The vegetation surrounding GOs is strongly related to structural vegetation types (Kappa = 0.8) and to its spatial context. Water gaining sites around GOs are characterized by taller and denser vegetation in all areas. The strong relationship between rainfall, soil-depth, and vegetation structure (R2 of 0.8–0.9) allowed comparisons of vegetation structure between current and future climate. Significant shifts in vegetation structural types were predicted and mapped for future climates. Water gaining areas below granite outcrops were identified as important putative refugia. A reduction in rainfall may be offset by the occurrence of deeper soil elsewhere on the outcrop. However, climate change interactions with fire and water table declines may render our conclusions conservative. The LiDAR-based mapping approach presented enables the integration of site-based biotic assessment with structural vegetation types for the rapid delineation and prioritization of key refugia.

High population differentiation and extensive clonality in a rare mallee eucalypt: Eucalyptus curtisii Conservation genetics of a rare mallee eucalypt

Microsatellite polymorphisms were analysed toassess the extent and pattern of geneticdiversity within and between isolatedpopulations of the rare mallee eucalypt, Eucalyptus curtisii. Twelve populations intotal were sampled throughout the 500 km rangeof the species in South-east Queensland.Results from analysis of 5 loci indicated ahigh degree of clonality within many of thesites, with two populations being comprised ofsingle genets. Estimates of radial growth ratessuggest that these clones may be between 4000and 9000 years old. Low overall levels ofgenetic diversity were recorded for thespecies, He = 0.54, however a highlysignificant amount of populationdifferentiation was observed, RST =0.22. There was no evidence of isolation bydistance and although there were morphologicaldifferences between some populations, this wasunrelated to molecular variation.The low level of genetic diversity and highproportion of interpopulation variation agreeswith the findings of other studies onregionally distributed eucalypts. The findingsindicate that previous estimates of theeffective population size of the species arelargely overestimated and that the individualpopulations are sufficiently differentiatedthat they should be treated as separatemanagement units. Further study is recommendedto elucidate the full extent of clonality inthe species and to conduct germination trialson seed collected from clonal populations.

High population differentiation and extensive clonality in a rare mallee eucalypt: Eucalyptus curtisii.

Microsatellite polymorphisms were analysed toassess the extent and pattern of geneticdiversity within and between isolatedpopulations of the rare mallee eucalypt, Eucalyptus curtisii. Twelve populations intotal were sampled throughout the 500 km rangeof the species in South-east Queensland.Results from analysis of 5 loci indicated ahigh degree of clonality within many of thesites, with two populations being comprised ofsingle genets. Estimates of radial growth ratessuggest that these clones may be between 4000and 9000 years old. Low overall levels ofgenetic diversity were recorded for thespecies, He = 0.54, however a highlysignificant amount of populationdifferentiation was observed, RST =0.22. There was no evidence of isolation bydistance and although there were morphologicaldifferences between some populations, this wasunrelated to molecular variation.The low level of genetic diversity and highproportion of interpopulation variation agreeswith the findings of other studies onregionally distributed eucalypts. The findingsindicate that previous estimates of theeffective population size of the species arelargely overestimated and that the individualpopulations are sufficiently differentiatedthat they should be treated as separatemanagement units. Further study is recommendedto elucidate the full extent of clonality inthe species and to conduct germination trialson seed collected from clonal populations.

A Review of Eucalypt Dieback Associated With Bell Miner Habitat in South-Eastern Australia

Summary We aim to assess current knowledge, and identify gaps in knowledge concerning bell-miner-associated dieback (BMAD) in south-eastern Australia. We review BMAD as a form of forest dieback, and bell miner and psyllid interrelations. We then consider indirect and direct causal factors associated with local functional scales (tree crown), and finally, indirect and direct causal factors associated with broader functional scales (forest stand and landscape processes). This paper emphasises published literature and is a summary of a more detailed report prepared for the BMAD working group which explicitly included personal communications with many researchers, managers and members of conservation groups and the timber industry. We conclude that BMAD is a significant threat to the sustainability of the moist eucalypt forests of north-eastern NSW and south-eastern Queensland, and to biodiversity conservation at a national scale. There are serious deficiencies in the information base for most BMAD issues. While there are clear interactions between bell miners and psyllids. there are many other, less well quantified interactions that may be of greater significance to the development of the problem. We suggest that management and research efforts towards solutions urgently target disturbances that lead to changes in forest canopy structure, but there is unlikely to be a single or simple management solution. An integrated management program will be necessary as concentration on particular management regimes in isolation is unlikely to resolve the BMAD problem because BMAD is associated with interacting disturbances.

Towards resolving conflict between forestry and conservation in Western Australia

SUMMARY There is widespread agreement that the indigenous forests of south-western Australia are an important refuge for wildlife in an otherwise extensively cleared landscape and that sustainable use of these forests is possible. Nevertheless, principles-based theses that have been proposed for assessing sustainability of forest use are of limited value unless they include assessable criteria for application. We argue that it is important to recognise that ecological science, like other disciplines is value-laden and that a statement of values is an important part of the scientific process. Furthermore, we believe that there is presently inadequate evidence to judge whether or not the current forest use is sustainable. Several areas of empirical work are suggested to resolve the outstanding issues. ‘The value of criticism and dissenting views is that they force a clearer articulation of the questions and the range of possible answers. This is the process that will hasten the resolution of fundamental iss...