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The majority of the world's population growth to 2050 is projected to occur in the tropics. Hence, there is a serious need for robust methods for undertaking water resource assessments to underpin the sustainable management of water in tropical regions. This paper describes the largest and most comprehensive assessment of the future impacts of runoff undertaken in a tropical region using conceptual rainfall-runoff models (RRMs). Five conceptual RRMs were calibrated using data from 115 streamflow gauging stations, and model parameters were regionalized using a combination of spatial proximity and catchment similarity. Future rainfall and evapotranspiration projections (denoted here as GCMES) were transformed to catchment-scale variables by empirically scaling (ES) the historical climate series, informed by 15 global climate models (GCMs), to reflect a 1°C increase in global average surface air temperature. Using the best-performing RRM ensemble, approximately half the GCMES used resulted in a spatially averaged increase in mean annual runoff (by up to 29%%) and half resulted in a decrease (by up to 26%%). However, ~70%% of the GCMES resulted in a difference of within ±5%% of the historical rainfall (1930-2007). The range in modeled impact on runoff, as estimated by five RRMs (for individual GCMES), was compared to the range in modeled runoff using 15 GCMES (for individual RRMs). For mid- to high runoff metrics, better predictions will come from improved GCMES projections. A new finding of this study is that in the wet-dry tropics, for extremely large runoff events and low flows, improvements are needed in both GCMES and rainfall-runoff modeling. [ABSTRACT FROM AUTHOR]

Periodic vegetation patterns (PVPs) are striking features of many global drylands. Although they have attracted wide research study, resulting in many hypotheses, their origin and controlling factors remain unresolved. Theoretical works dominate a large literature seeking to account for the occurrence and properties of PVPs, especially banded vegetation patterns ('tiger bush'). In light of the plethora of theoretical studies, there is a need for more empirical observation and monitoring of PVPs, especially their responses to climatic variability and to foreshadowed climatic change. This paper highlights key results derived from more than 20 years of field study and monitoring of banded vegetation in arid New South Wales, Australia, where severe drought is a recurring feature. It advances the view that in this study area, and hence perhaps in other regions, local factors including plant physiology, soil properties, and climatic characteristics result in PVPs whose development and functioning might be quite unlike those of other regions. Importantly, these local characteristics appear to confer on the regional PVPs a considerable resilience to drought, and hence perhps to climate change. The field evidence from the study area suggests that, despite predictions of a number of theoretical analyses, the PVPs are not facing imminent collapse. Generalised and non-specific models of PVPs require more realistic parameterisation and more thorough validation than has been customary, and this will require additional field evidence of the kind reviewed here. Highlights: • highlights results of field study of banded vegetation in the Broken Hill region of Australia over more than 20 years • patterned vegetation in this area appears to be resilient in the face of drought and grazing pressure • contrary to most model predictions, the vegetation bands do not migrate upslope, and do not undergo pattern change during severe drought • direct observation of banded vegetation should increasingly accompany attempts at modelling responses of global drylands to climate change. [ABSTRACT FROM AUTHOR]

Aim: Geographic range size varies greatly across species. Climate, along with aspects of a species' biology, may influence its spatial extent. We investigate intrinsic and extrinsic predictors of range size in Australian skinks. We predicted that larger body size, longer limbs, and larger clutch sizes would be associated with larger ranges, and that ranges would be larger in colder, more arid, and more seasonal climates. Location: Mainland Australia. Taxon: Skinks (Scincidae). Methods: We test for climatic and geographic correlates of range size of Australian skink species (417 of 462 described species), as well as investigate the effects of body size and clutch size (259 species). We compare detailed morphological measurements of 1,324 specimens across nine pairs of widespread and narrow‐ranged congeneric species to investigate the roles of intrinsic (body size, clutch size, morphology) and extrinsic (mean temperature and precipitation) factors in determining range size. Results: In the broader analysis, large range sizes were associated with the presence of fully developed limbs, low precipitation seasonality, high temperatures, and high precipitation. Ranges of species traversing the Great Dividing Range are larger by an order of magnitude than those east of the range, with western ranges being intermediate. Affinity to specific biomes explained less variation than climatic variables. For the nine species pairs, wide‐ranging species share similar morphologies and clutch sizes with overlapping narrow‐ranging congeners, but generally inhabit more arid regions. Main conclusions: We found several extrinsic, but few intrinsic, factors were correlated with range size. The narrow mesic belts in Australia compared with the extensive expanse of arid and semi‐arid regions may explain why desert species have larger ranges. This interpretation agrees with the notion that the size of the domain, here a climatic domain rather than a physical one, may exert strong influence on species' range sizes. [ABSTRACT FROM AUTHOR]