Michael Dunlop

Predicting Dispersal Spectra: A Minimal Set of Hypotheses Based on Plant Attributes

1 The dispersal mode adopted by a plant species is frequently associated with other attributes of the plant and its habitat. In this paper we review these associations and present a set of hypotheses which, when considered together, make a probabilistic prediction of the dispersal mode adopted by a plant species. When applied to a species list, the hypotheses can be used to generate a prediction of its dispersal spectrum, i.e. the percentages of different dispersal modes that have been adopted. 2 The formulation of such a set of hypotheses has several purposes: (i) to summarize existing knowledge about dispersal adaptations and their interrelations with other attributes of plants and their habitats; (ii) to couch that knowledge in such a way that falsifiable predictions can be made; (iii) to arrive at provisional conclusions about which factors are the most important in shaping the evolution of dispersal mode in different plants or different environments. 3 The review of relationships between dispersal mode and other attributes of plants and their habitats lead to the following provisional conclusions; (i) seeds larger than 100 mg tend to be adapted for dispersal by vertebrates while those smaller than 0.1 mg tend to be unassisted; most seeds, however, are between 0.1 and 100 mg, and in this range all of the dispersal modes are feasible; (ii) plant growth form and stature (sometimes in relation to the canopy height of the vegetation) seem to exclude certain dispersal modes; (iii) the availability of specific dispersal vectors seems rarely to be an important determinant of dispersal mode; (iv) attributes of the physical environment also seem rarely to be important, except indirectly through their influence on plant stature and seed size.

An assessment of biomass for bioelectricity and biofuel, and for greenhouse gas emission reduction in Australia

We provide a quantitative assessment of the prospects for current and future biomass feedstocks for bioenergy in Australia, and associated estimates of the greenhouse gas (GHG) mitigation resulting from their use for production of biofuels or bioelectricity. National statistics were used to estimate current annual production from agricultural and forest production systems. Crop residues were estimated from grain production and harvest index. Wood production statistics and spatial modelling of forest growth were used to estimate quantities of pulpwood, in‐forest residues, and wood processing residues. Possible new production systems for oil from algae and the oil‐seed tree Pongamia pinnata, and of lignocellulosic biomass production from short‐rotation coppiced eucalypt crops were also examined. The following constraints were applied to biomass production and use: avoiding clearing of native vegetation; minimizing impacts on domestic food security; retaining a portion of agricultural and forest residues to protect soil; and minimizing the impact on local processing industries by diverting only the export fraction of grains or pulpwood to bioenergy. We estimated that it would be physically possible to produce 9.6 GL yr−1 of first generation ethanol from current production systems, replacing 6.5 GL yr−1 of gasoline or 34% of current gasoline usage. Current production systems for waste oil, tallow and canola seed could produce 0.9 GL yr−1 of biodiesel, or 4% of current diesel usage. Cellulosic biomass from current agricultural and forestry production systems (including biomass from hardwood plantations maturing by 2030) could produce 9.5 GL yr−1 of ethanol, replacing 6.4 GL yr−1 of gasoline, or ca. 34% of current consumption. The same lignocellulosic sources could instead provide 35 TWh yr−1, or ca. 15% of current electricity production. New production systems using algae and P. pinnata could produce ca. 3.96 and 0.9 GL biodiesel yr−1, respectively. In combination, they could replace 4.2 GL yr−1 of fossil diesel, or 23% of current usage. Short‐rotation coppiced eucalypt crops could provide 4.3 GL yr−1 of ethanol (2.9 GL yr−1 replacement, or 15% of current gasoline use) or 20.2 TWh yr−1 of electricity (9% of current generation). In total, first and second generation fuels from current and new production systems could mitigate 26 Mt CO2‐e, which is 38% of road transport emissions and 5% of the national emissions. Second generation fuels from current and new production systems could mitigate 13 Mt CO2‐e, which is 19% of road transport emissions and 2.4% of the national emissions lignocellulose from current and new production systems could mitigate 48 Mt CO2‐e, which is 28% of electricity emissions and 9% of the national emissions. There are challenging sustainability issues to consider in the production of large amounts of feedstock for bioenergy in Australia. Bioenergy production can have either positive or negative impacts. Although only the export fraction of grains and sugar was used to estimate first generation biofuels so that domestic food security was not affected, it would have an impact on food supply elsewhere. Environmental impacts on soil, water and biodiversity can be significant because of the large land base involved, and the likely use of intensive harvest regimes. These require careful management. Social impacts could be significant if there were to be large‐scale change in land use or management. In addition, although the economic considerations of feedstock production were not covered in this article, they will be the ultimate drivers of industry development. They are uncertain and are highly dependent on government policies (e.g. the price on carbon, GHG mitigation and renewable energy targets, mandates for renewable fuels), the price of fossil oil, and the scale of the industry.

Building resilient pathways to transformation when “no one is in charge”: insights from Australia's Murray-Darling Basin

Climate change and its interactions with complex socioeconomic dynamics dictate the need for decision makers to move from incremental adaptation toward transformation as societies try to cope with unprecedented and uncertain change. Developing pathways toward transformation is especially difficult in regions with multiple contested resource uses and rights, with diverse decision makers and rules, and where high uncertainty is generated by differences in stakeholders’ values, understanding of climate change, and ways of adapting. Such a region is the Murray-Darling Basin, Australia, from which we provide insights for developing a process to address these constraints. We present criteria for sequencing actions along adaptation pathways: feasibility of the action within the current decision context, its facilitation of other actions, its role in averting exceedance of a critical threshold, its robustness and resilience under diverse and unexpected shocks, its effect on future options, its lead time, and its effects on equity and social cohesion. These criteria could potentially enable development of multiple stakeholder-specific adaptation pathways through a regional collective action process. The actual implementation of these multiple adaptation pathways will be highly uncertain and politically difficult because of fixity of resource-use rights, unequal distribution of power, value conflicts, and the likely redistribution of benefits and costs. We propose that the approach we outline for building resilient pathways to transformation is a flexible and credible way of negotiating these challenges.

Combining community-level spatial modelling and expert knowledge to inform climate adaptation in temperate grassy eucalypt woodlands and related grasslands

Many studies predict effects of future climate scenarios on species distributions, but few predict impacts on landscapes or ecological communities, the scales most relevant to conservation management. We combined expert knowledge with community-level spatial modelling (using artificial neural networks, ANN, and generalised dissimilarity modelling, GDM) to inform climate adaptation management in widespread but highly threatened temperate grassy ecosystems (TGE) of Australian agricultural landscapes. GDM predicted high levels of ‘biotically-scaled environmental stress’ (scaled in terms of potential change in species composition of communities) for plants, reptiles and snails within the TGE under medium, and especially high, 2070 climate scenarios. Predicted stress was lower for birds, mammals and frogs, possibly owing to generally wider species distributions, but these models do not account for changing habitat characteristics. ANN predicted environments within the current TGE biome will become increasingly favourable for formations such as chenopod shrublands, Casuarina L. forests and Callitris Vent. forests by 2070, although classification error for eucalypt woodland in current climates was high. Expert knowledge and GDM suggest these predictions may be mediated by attributes such as environmental heterogeneity that confer resilience, but GDM confirms that widespread degradation has greatly compromised the capacity of TGE to adapt to change. Based on model predictions and expert knowledge we discuss five potential climate change outcomes for TGE: decreasing fire frequency, structural change, altered functional composition, exotic invasion, and cascading changes in ecological interactions. Although significant ecological change in TGE is likely, it is feasible to ameliorate non-climatic limits to adaptation and promote reassembly by native rather than exotic species. Current conservation efforts already target similar goals, and reinforcing and adjusting these approaches offer the highest priority, lowest risk climate adaptation options. We conclude that despite high uncertainties, combining community-level modelling with expert knowledge can guide climate adaptation management.

Future oriented conservation: knowledge governance, uncertainty and learning

Despite significant progress in understanding climate risks, adaptation efforts in biodiversity conservation remain limited. Adaptation requires addressing immediate conservation threats while also attending to long term, highly uncertain and potentially transformative future changes. To date, conservation research has focused more on projecting climate impacts and identifying possible strategies, rather than understanding how governance enables or constrains adaptation actions. We outline an approach to future-oriented conservation that combines the capacities to anticipate future ecological change; to understand the implications of that change for social, political and ecological values; and the ability to engage with the governance (and politics) of adaptation. Our approach builds on the adaptive management and governance literature, however we explicitly address the (often contested) rules, knowledge and values that enable or constrain adaptation. We call for a broader focus that extends beyond technical approaches to acknowledge the socio-political challenges inherent to adaptation. More importantly, we suggest that conservation policy makers and practitioners can use this approach to facilitate learning and adaptation in the context of complexity, transformational change and uncertainty.

Why biodiversity declines as protected areas increase: the effect of the power of governance regimes on sustainable landscapes

Achieving sustainable landscapes that integrate food production with biodiversity conservation remains challenging, particularly in the tropics where most forest clearance results from conversion to industrial agriculture. Land-sparing (delineating protected areas and intensifying agricultural production from developed land) has often been identified as more effective than land-sharing (mixing protection and production in an agro-ecological matrix) for biodiversity in the tropics. Nevertheless, biodiversity decline continues despite protected area expansion meeting global targets under international conventions. We developed a low-order stock-and-flow model to consider this apparent paradox, and used it to structure deliberations on the impacts of the power of governance regimes. The model articulates our shared hypothesis about the basic dynamics of the social–ecological system. We present scenarios that depict plausible biodiversity change over time under three different governance regimes and land-use trajectories. The scenarios raise the possibility that, while land-sparing gives better short-term results for biodiversity, land-sharing may outperform it over time. Two key insights derive from our deliberations. First, the forces that drive forest clearance for development do not necessarily oppose those that drive forest protection; this decoupling helps explain why biodiversity loss continues as protected areas increase. Second, the power of the governance regimes that protect existing forest can be weakened by protected area expansion, through lowering public discourse about risks from biodiversity loss, while the power of governance regimes for development concurrently remain strong; this helps explains why some REDD+ schemes are associated with increasing deforestation. These insights suggest novel leverage points for sustainable tropical landscapes, such as prioritising protected area placement by proximity to active agricultural frontiers, rather than by representative biodiversity or cost-effectiveness; or using area-based conservation targets that include both the extent of protected areas and of other remaining forest habitat. We recommend further investigation of these ideas, and of collaborative conceptual modelling approaches, to explore solutions for sustainable tropical landscapes.

Adaptation services of floodplains and wetlands under transformational climate change

Adaptation services are the ecosystem processes and services that benefit people by increasing their ability to adapt to change. Benefits may accrue from existing but newly used services where ecosystems persist or from novel services supplied following ecosystem transformation. Ecosystem properties that enable persistence or transformation are important adaptation services because they support future options. The adaptation services approach can be applied to decisions on trade-offs between currently valued services and benefits from maintaining future options. For example, ecosystem functions and services of floodplains depend on river flows. In those regions of the world where climate change projections are for hotter, drier conditions, floods will be less frequent and floodplains will either persist, though with modified structure and function, or transform to terrestrial (flood-independent) ecosystems. Many currently valued ecosystem services will reduce in supply or become unavailable, but new options are provided by adaptation services. We present a case study from the Murray-Darling Basin, Australia, for operationalizing the adaptation services concept for floodplains and wetlands. We found large changes in flow and flood regimes are likely under a scenario of +1.6°C by 2030, even with additional water restored to rivers under the proposed Murray-Darling Basin Plan. We predict major changes to floodplain ecosystems, including contraction of riparian forests and woodlands and expansion of terrestrial, drought-tolerant vegetation communities. Examples of adaptation services under this scenario include substitution of irrigated agriculture with dryland cropping and floodplain grazing; mitigation of damage from rarer, extreme floods; and increased tourism, recreational, and cultural values derived from fewer, smaller wetlands that can be maintained with environmental flows. Management for adaptation services will require decisions on where intervention can enable ecosystem persistence and where transformation is inevitable. New ways of managing water that include consideration of the increasing importance of adaptation services requires major changes to decision-making that better account for landscape heterogeneity and large-scale change rather than attempting to maintain ecosystems in fixed states.

Adaptation services and pathways for the management of temperate montane forests under transformational climate change

In regions prone to wildfire, a major driver of ecosystem change is increased frequency and intensity of fire events caused by a warming, drying climate. Uncertainty over the nature and extent of change creates challenges for how to manage ecosystems subject to altered structure and function under climate change. Using montane forests in south-eastern Australia as a case study, we addressed this issue by developing an ecosystem state-and-transition model based on a synthesis of expert knowledge and published data, with fire frequency and intensity as drivers. We then used four steps to determine future adaptation options: (1) estimation of changes in ecosystem services under each ecosystem state to identify adaptation services: the ecosystem processes and services that help people adapt to environmental change; (2) identification and sequencing of decision points to maintain each ecosystem state or allow transition to an alternative state; (3) analysis of interactions between societal values, scientific and management knowledge and institutional rules (vrk) required to reframe the decision context for future management, and (4) determining options for an adaptation pathway for management of montane forests under climate change. Our approach is transferable to other ecosystems for which alternative states can be predicted under climate change.

Second harvest-is there sufficient stubble for biofuel production in Australia?

Identifying the location and amount of grain crop residues (stubble) in Australia is necessary for determining the viability of potential biofuel plant locations. We combined 22 years of crop statistics with harvest indices and land use to arrive at spatially explicit stubble productivity figures. Stubble quantities using different focal radii and from different seasons provide an insight into the feasibility of its use for bioenergy. We focus on areas where the stubble concentrations within a 50 km radius were at least 500 kt per year; the amount suggested for a viable lignocellolosic bioethanol facility. The outcome of this study has been to show, for the first time, where there are large amounts of stubble in Australia. Whether the supply of stubble is sufficiently constant over time and indeed available at a price that is economic for a biofuel plant must be subject to future work.