Lynda E. Chambers

Near-Global Sea Surface Temperature Anomalies as Predictors of Australian Seasonal Rainfall

An operational system for the prediction of Australian seasonal rainfall variations using sea surface temperature anomaly (SSTA) patterns over the Indian and Pacific Oceans is described. The SSTA patterns are represented by rotated principal components, with individual monthly values at 1- and 3-month lead times used as predictors; for example, November and January SSTAs are used to forecast March‐May seasonal rainfall. The historical seasonal rainfall is also represented by rotated principal components of a gridded 1 8 rainfall dataset, with the principal component loadings used as weights to project the forecasts back to the original 1 8 grid points. Forecasts of seasonal rainfall in two (above/below median) or three categories (terciles) are produced using linear discriminant analysis. Hindcast skill, measured by the linear error in probability space (LEPS) skill score has been assessed using cross validation. Experiments were also performed using a double or nested crossvalidation procedure to select the best model or combination of predictors. The model chosen for operational seasonal forecasts uses the first two rotated SSTA components lagged by 1 and 3 months as predictors for every season and location, to maintain continuity of forecast probabilities between the overlapping 3-month seasons. Current values of the principal component amplitudes are calculated by projecting either the Bureau of Meteorology’s or the National Centers for Environmental Prediction’s SST analysis onto the set of SST principal components. The hindcasts and experimental real-time forecasts over the 5-yr period from January‐March 1994 to December‐February 1998/99 indicate improved skill over parts of southern Australia during the autumn period using the SST-based schemes when compared with forecasts using the Southern Oscillation index alone.

Phenological changes in the southern hemisphere.

Current evidence of phenological responses to recent climate change is substantially biased towards northern hemisphere temperate regions. Given regional differences in climate change, shifts in phenology will not be uniform across the globe, and conclusions drawn from temperate systems in the northern hemisphere might not be applicable to other regions on the planet. We conduct the largest meta-analysis to date of phenological drivers and trends among southern hemisphere species, assessing 1208 long-term datasets from 89 studies on 347 species. Data were mostly from Australasia (Australia and New Zealand), South America and the Antarctic/subantarctic, and focused primarily on plants and birds. This meta-analysis shows an advance in the timing of spring events (with a strong Australian data bias), although substantial differences in trends were apparent among taxonomic groups and regions. When only statistically significant trends were considered, 82% of terrestrial datasets and 42% of marine datasets demonstrated an advance in phenology. Temperature was most frequently identified as the primary driver of phenological changes; however, in many studies it was the only climate variable considered. When precipitation was examined, it often played a key role but, in contrast with temperature, the direction of phenological shifts in response to precipitation variation was difficult to predict a priori. We discuss how phenological information can inform the adaptive capacity of species, their resilience, and constraints on autonomous adaptation. We also highlight serious weaknesses in past and current data collection and analyses at large regional scales (with very few studies in the tropics or from Africa) and dramatic taxonomic biases. If accurate predictions regarding the general effects of climate change on the biology of organisms are to be made, data collection policies focussing on targeting data-deficient regions and taxa need to be financially and logistically supported.

Climate change and its impact on Australia's avifauna

Abstract Relative to the northern hemisphere, little is known about the effect of climate change on southern hemisphere birds, although the impact could be significant. Here we review the effects of climate change on birds that have been documented or predicted, with particular reference to Australian species. Potential impacts include changes in geographic range, movement patterns, morphology, physiology, abundance, phenology and community composition. The evidence suggests that these changes are already happening, both overseas and in Australia, but more research is needed to determine the extent of these impacts and how to conserve birds in the face of climate change. Management options include promoting adaptation and resilience, intensive management of sensitive species, and improved planning for mitigation techniques and monitoring.

Riparian Ecosystems in the 21st Century: Hotspots for Climate Change Adaptation?

Riparian ecosystems in the 21st century are likely to play a critical role in determining the vulnerability of natural and human systems to climate change, and in influencing the capacity of these systems to adapt. Some authors have suggested that riparian ecosystems are particularly vulnerable to climate change impacts due to their high levels of exposure and sensitivity to climatic stimuli, and their history of degradation. Others have highlighted the probable resilience of riparian ecosystems to climate change as a result of their evolution under high levels of climatic and environmental variability. We synthesize current knowledge of the vulnerability of riparian ecosystems to climate change by assessing the potential exposure, sensitivity, and adaptive capacity of their key components and processes, as well as ecosystem functions, goods and services, to projected global climatic changes. We review key pathways for ecological and human adaptation for the maintenance, restoration and enhancement of riparian ecosystem functions, goods and services and present emerging principles for planned adaptation. Our synthesis suggests that, in the absence of adaptation, riparian ecosystems are likely to be highly vulnerable to climate change impacts. However, given the critical role of riparian ecosystem functions in landscapes, as well as the strong links between riparian ecosystems and human well-being, considerable means, motives and opportunities for strategically planned adaptation to climate change also exist. The need for planned adaptation of and for riparian ecosystems is likely to be strengthened as the importance of many riparian ecosystem functions, goods and services will grow under a changing climate. Consequently, riparian ecosystems are likely to become adaptation ‘hotspots’ as the century unfolds.

Observed and predicted effects of climate on Australian seabirds

Abstract Although there is growing evidence of climate warming, for many regions the broader effects of climate variation on marine top predators remains unknown owing to the difficulty in obtaining, for synthesis, long-term and short-term datasets on multiple species. In the Australian region, climatic and oceanographic variability and change have been shown to affect marine species, often with profound consequences. Many seabirds are apex predators for which changes in climatic and oceanic dynamics have driven range movements poleward, reduced breeding success and altered breeding timing for some species. Here we review the literature to assess and determine the vulnerability of Australian seabirds to variation and change in climate and identify which species and ecosystems may be more resilient to future climate warming. It is clear from this synthesis that not all Australian seabirds are affected similarly, with responses varying by species and location. In addition, the paucity of information on the distribution and biology of seabird prey, foraging patterns and movements of seabirds, and the ability of seabirds to switch between prey species or adjust timing of life-cycles make generalisations about potential effects of future climate change and adaptive capacity in seabirds difficult. This applies both within Australia and elsewhere, where data are similarly sparse.

Predicting Novel Riparian Ecosystems in a Changing Climate

Rapid changes in global climate are likely to alter species assemblages and environmental characteristics resulting in novel ecosystems. The ability to predict characteristics of future ecosystems is crucial for environmental planning and the development of effective climate change adaptation strategies. This paper presents an approach for envisioning novel ecosystems in future climates. Focusing on riparian ecosystems, we use qualitative process models to predict likely abiotic and biotic changes in four case study systems: tropical coastal floodplains, temperate streams, high mountain streams and urban riparian zones. We concentrate on functional groups rather than individual species and consider dispersal constraints and the capacity for genetic adaptation. Our scenarios suggest that climatic changes will reduce indigenous diversity, facilitate non-indigenous invasion (especially C4 graminoids), increase fragmentation and result in simplified and less distinctive riparian ecosystems. Compared to models based on biota-environment correlations, process models built on mechanistic understanding (like Bayesian belief networks) are more likely to remain valid under novel climatic conditions. We posit that predictions based on species’ functional traits will facilitate regional comparisons and can highlight effects of climate change on ecosystem structure and function. Ecosystems that have experienced similar modification to that expected under climate change (for example, altered flow regimes of regulated rivers) can be used to help inform and evaluate predictions. By manipulating attributes of these system models (for example, magnitude of climatic changes or adaptation strategies used), implications of various scenarios can be assessed and optimal management strategies identified.

Data Rescue in the Southeast Asia and South Pacific Region: Challenges and Opportunities

BY CHER M. PAGE, NEVILLE NICHOLLS, NEIL PLUMMER, BLAIR TREWIN, MIKE MANTON, LISA ALEXANDER, LYNDA E. CHAMBERS, YOUNGEUN CHOI, DEAN A. COLLINS, ASHMITA GOSAI, PAUL DELLA-MARTA, MALCOLM R. HAYLOCK, KASIS INAPE, VICTOIRE LAURENT, LUC MAITREPIERRE, ERWIN E.P. MAKMUR, HIROSHI NAKAMIGAWA, NONGNAT OUPRASITWONG, SIMON MCGREE, JANITA PAHALAD, M.J. SALINGER, LOURDES TIBIG, TRONG D. TRAN, KALIAPAN VEDIAPAN, AND PANMAO ZHAI

Dynamical Seasonal Forecasts during the 1997/98 ENSO Using Persisted SST Anomalies

Abstract An evaluation of trial seasonal forecasts during the 1997/98 El Nino, using an atmospheric GCM forced by persisted sea surface temperature and sea-ice anomalies, is presented. Generally, forecasts of seasonal anomalies of precipitation, surface air temperature, 200-hPa geopotential height, and mean sea level pressure (MSLP) are shown to have statistically significant skill in the Tropics and subtropics, but predominantly over the oceans. Surface air temperature and 200-hPa height anomalies are also skillfully forecast over land in the 30°S–30°N latitudinal band, and, in contrast to precipitation and MSLP, also show significant skill in the extratropics. The global pattern of significant skill seems not to be oversensitive to the use of a Kuo or a mass-flux convection scheme (Tiedtke), although the global root-mean-square errors are consistently larger, in the latter case. Results from multidecadal simulations of the model, when forced by observed sea surface temperature and sea-ice, show that the...

Trends in timing of migration of south-western Australian birds and their relationship to climate

Abstract The influence of climate on the timing of migration of Australian birds is poorly understood, particularly in Western Australia and for waterfowl. This paper examines a new dataset, comprising presence—absence records of 20 species of waterbirds and landbirds at Middlesex, south-western Australia, for the period 1973–2000. Considering only species with sufficient records to determine trends, over this period nine of 19 species (47%) had significantly altered arrival times (five arriving earlier and four later); seven of 17 species (41%) had significant changes in departure dates (four departing later, three earlier); and eight of 17 (47%) species had significantly different season lengths (the period spent at Middlesex, with five spending more time at Middlesex). Generally, changes in the timing of regular seasonal movements were consistent among species that arrived or departed in similar seasons, with species that arrive in spring tending to arrive earlier, while species arriving in autumn and winter arrived later. Trends were generally more pronounced in spring-arriving species, though strong trends were also seen in other seasons. This region experienced significant reductions in the number of rain-days and increased minimum temperature over the study period. For many Middlesex species, particularly waterbirds, precipitation changes appeared to have a greater influence on changes in migration timing than temperature, though some species also appeared to respond to changes in extreme temperatures. This differs from many northern hemisphere studies, where changes in mean, maximum, or minimum temperature were associated with changes in migration timing.

Poorer breeding by little penguins near Perth, Western Australia is correlated with above average sea surface temperatures and a stronger Leeuwin Current

Using 20 years of data (1986 to 2008), we examined relationships between oceanographic variables (Fremantle sea level (FSL) – a proxy for the strength of the Leeuwin Current – and sea surface temperature (SST)) and five measures of little penguin, Eudyptula minor, breeding performance near Perth, Western Australia: namely (1) the laying date, (2) the number of chicks produced per pair, (3) the proportion of eggs that hatched, (4) the overall breeding success, defined as the proportion of total eggs laid that resulted in successful fledglings and (5) chick mass at fledging. The next three years of data (2009 to 2011) were used to test the performance of our statistical predictive models. FSL provided more accurate predictions of timing of laying, whereas SST provided more accurate predictions of breeding success. A later end to laying was associated with a high FSL during the summer (December to February) before breeding. Higher SSTs in the pre-breeding period from April to May corresponded to reduced breeding success, with lower fledgling success, fewer chicks per pair and generally a lower mean mass of chicks at fledging. The models predict that future oceanographic warming is expected to reduce the breeding success of this colony of little penguins.