Estimating future changes in flood risk: case study of the Brisbane River, Australia

Estimates of potential changes to flood risk due to climate change can be of great value but are difficult to estimate for various reasons including uncertain rainfall projections and problems associated with transforming model rainfall values into runoff and inflows at relevant catchment scales. Here we attempt to estimate changes to flood risk for the Brisbane River region of south-east Queensland which has a long history of serious flood events but which now benefits from the mitigating effect of the upstream Wivenhoe Dam. In this specific case study, the existence of good quality long-term records of rainfall, a relatively large number of climate model projections and the fact that the storage levels within the dam can be reasonably simulated as a function of annual rainfall totals provides a basis for estimating possible changes to flood risk. Changes to the risk of more serious floods is assumed to depend on changes to either the magnitude or frequency of extreme rainfall events combined with changes to the amount of water actually stored in the dam. An increase in extreme rainfall events could be offset by lower annual rainfall totals that effectively increase the mitigation capacity of the Dam. We analyse the results from climate models which simulate the effect of increased greenhouse gas emissions and note that they tend to favour an increase in the former and a decrease in the latter. As a consequence, the model results indicate a range of possible outcomes with no clear tendency one way or another. This outcome reflects the fundamental nature of the climate model results for rainfall for this region and will, most likely, dominate all attempts to reduce uncertainty

Rainforest Reforestation and Biodiversity Benefits: A Case Study from the Australian Wet Tropics

This paper examines the effectiveness of a rainforest reforestation program (the Community Rainforest Reforestation Program in north-eastern Queensland, Australia) in providing amenity and biodiversity benefits. This program involved small areas of mainly mixed native timber species on private farmland. Government support was provided for the program, for both timber production and environmental reasons. Survey results reveal that landholders have planted trees, and intend to manage plantations, for diverse reasons, including conservation purposes. The plantings appear to be of environmental value, forming wildlife corridors and buffer areas. In this respect, the CRRP has achieved a limited success in meeting the implicit goal of biological conservation

Power, politics and policy in the appropriation of urban wetlands: the critical case of Sri Lanka

Little is known about the drivers and governance strategies of appropriation of urban nature in the global south. We compare urban land-grabbing in the city of Colombo, Sri Lanka, with broader understanding of rural land-grabbing in the developing world. We show that the colonial legacy of appropriation and alteration of urban wetlands in Colombo has attained new heights in the neo-liberal period. This cyclical process has caused acute irreversible damage to the wetland ecosystem and a vast majority of the urban poor, with the marginalised continuing to suffer dispossession and environmental hazard. In recognition of the inherent limitations of 'uncontrollable' hybrid ecologies, potent social struggles have emerged to resist the continued appropriation agenda. As this cycle is perpetuated, broader social struggles for democratic urban governance have overtaken the pursuit of narrow political-economic goals and internal policy reform

Climate-Relevant Land Use and Land Cover Change Policies

Both observational and modeling studies clearly demonstrate that land-use and land-cover change (LULCC) play an important biogeophysical and biogeochemical role in the climate system from the landscape to regional and even continental scales. Without comprehensively considering these impacts, an adequate response to the threats posed by human intervention into the climate system will not be adequate. Public policy plays an important role in shaping local- to national-scale land-use practices. An array of national policies has been developed to influence the nature and spatial extent of LULCC. Observational evidence suggests that these policies, in addition to international trade treaties and protocols, have direct effects on LULCC and thus the climate system. However, these policies, agreements, and protocols fail to adequately recognize these impacts. To make these more effective and thus to minimize climatic impacts, we propose several recommendations: 1) translating international treaties and protocols into national policies and actions to ensure positive climate outcomes; 2) updating international protocols to reflect advancement in climate–LULCC science; 3) continuing to invest in the measurements, databases, reporting, and verification activities associated with LULCC and LULCC-relevant climate monitoring; and 4) reshaping Reducing Emissions from Deforestation and Forest Degradation+ (REDD+) to fully account for the multiscale biogeophysical and biogeochemical impacts of LULCC on the climate system

A spatially explicit habitat selection model incorporating home range behavior

Understanding habitat selection is of primary interest in theoretical and applied ecology. One approach is to infer habitat selection processes from differences in population densities between habitats using methods such as isodar and isoleg analysis. Another approach is to directly observe the movements of individuals. However, habitat selection models based on movement data often fail to adequately incorporate spatial processes. This is problematic if the probability of selecting a particular habitat is dependent upon its spatial context. This would occur, for example, where organisms exhibit home range behavior and the choice of habitat is dependent on its location relative to the home range. In this paper we present a spatially explicit habitat selection model for movement data that incorporates home range behavior as a spatial process. Our approach extends a previous model by formulating the probability of selecting a habitat as a function of its distance from the animal's current location and home range center. We demonstrate that these enhancements lead to more parsimonious models when applied to a koala radiotracking data set from eastern Australia. This approach could also be applied to modeling other spatial habitat selection processes, leading to more biologically meaningful models for a range of species and applications

Modelling the potential of integrated vegetation bands (IVB) to retain stormwater runoff on steep hillslopes of Southeast Queensland, Australia

Rainfall intensity is predicted to increase under a changing climate, leading to increased risks of hillslope erosion, downstream sedimentation and flooding. For many catchments used for grazing and agricultural land uses, it will become increasingly important to maintain ecohydrological functioning despite climatic extremes. One means to achieve this is through strategic reforestation using locally endemic species, in spatial configurations that effectively intercept, retain or and redistribute overland flows. This paper adopts a modelling approach for investigating the potential of one such design termed “integrated vegetation bands” (IVB), to increase the retention of runoff across steep hillslopes, particularly in the sub-tropics where rainstorms are becoming increasingly intense. A spatially distributed simulation model (MIKE-SHE) was applied to a steep, grazed catchment (Maronghi Creek catchment, Southeast Queensland, Australia) to compare stormwater runoff characteristics between: (1) the existing pasture land cover; and (2) a series of hypothetical IVB added across this pasture land. The IVB were approximately 20 m wide, and configured at 5% gradient towards ridgelines. Results for estimates of overland flow depth and infiltration (spatial), and accumulative water balance (temporal), confirm that the area of hillslope retaining > 10 mm/day more runoff increased by 22% under IVB compared to the pasture land use. Excluding the IVB themselves, the area of hillslope where runoff retention increased was 11%. During the most intense rainfall, IVB held up to 25% greater water depth and had 10% greater infiltration at the hillslope scale. At the sub-catchment scale, discharge decreased by 7% and infiltration increased by 23%. The findings for sub-tropical landscapes presented here are consistent with studies conducted in temperate regions. Based on the results of this preliminary modelling work, the IVB concept has been established as a paired-catchment field trial in a high rainfall catchment in Southeast Queensland, Australia

Despotic, high-impact species and the subcontinental scale control of avian assemblage structure

Some species have disproportionate influence on assemblage structure, given their numbers or biomass. Most examples of such "strong interactors'' come from small-scale experiments or from observations of the effects of invasive species. There is evidence that entire avian assemblages in open woodlands can be influenced strongly by individual species over very large areas in eastern Australia, with small-bodied species (2000 km). A series of linked Bayesian models was used to identify large-bodied (>= 50 g) bird species that were associated with changes in occurrence and abundance of small-bodied species. One native species, the Noisy Miner (Manorina melanocephala; family Meliphagidae), was objectively identified as the sole large-bodied species having similar detrimental effects in all districts, depressing occurrence of 57 of 71 small-bodied species. Adverse effects on abundances of small-bodied species were profound when the Noisy Miner occurred with mean site abundances >= 1.6 birds/2 ha. The Noisy Miner may be the first species to have been shown to influence whole-of-avifauna assemblage structure through despotic aggressiveness over subcontinental scales. These substantial shifts in occurrence rates and abundances of small-bodied species flow on to alter species abundance distributions of entire assemblages over much of eastern Australia

Planning guidelines for koala conservation and recovery: A guide to best planning practice

The information contained in the guide is a synthesis of four years research into the conservation and restoration of koala populations in fragmented landscapes of eastern Australia. The guidelines also capture a decade of practical research and planning experience by the Australian Koala Foundation in mapping koala habitat and developing koala conservation and management plans for local government areas in New South Wales. They draw on the collective knowledge of researchers who wanted to see their results put into action with practical outcomes for koala conservation