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The Ecological Society of Australia was founded in 1959, and the society's journal was first published in 1976. To examine how research published in the society's journal has changed over this time, we used text mining to quantify themes and trends in the body of work published by the Australian Journal of Ecology and Austral Ecology from 1976 to 2019. We used topic models to identify 30 'topics' within 2778 full‐text articles in 246 issues of the journal, followed by mixed modelling to identify topics with above‐average or below‐average popularity in terms of the number of publications or citations that they contain. We found high inter‐decadal turnover in research topics, with an early emphasis on highly specific ecosystems or processes giving way to a modern emphasis on community, spatial and fire ecology, invasive species and statistical modelling. Despite an early focus on Australian research, papers discussing South American ecosystems are now among the fastest‐growing and most frequently cited topics in the journal. Topics that were growing fastest in publication rates were not always the same as those with high citation rates. Our results provide a systematic breakdown of the topics that Austral Ecology authors and editors have chosen to research, publish and cite through time, providing a valuable window into the historical and emerging foci of the journal. [ABSTRACT FROM AUTHOR]

In exploring the relationship between multivariate abundance data and environmental variables, a rarely used approach is to graph raw data separately for each different taxon. It is proposed that such raw data graphs become part of the standard toolset for graphing and analysing multivariate abundances. The key advantage of this approach is that axis scales have quantitative interpretations, enabling quantitative interpretation of patterns in abundance. In contrast, ordinations only present qualitative information. Ordinations are useful for inferring overall, qualitative patterns and raw data graphing is a complementary tool of greater use for answering more specific questions, aimed at a deeper understanding the ecology of a community. It is demonstrated using some well-known examples that our understanding of the nature of associations can be considerably improved by using raw data graphs, even when only plotting a subset of variables. One example describes how an often-cited dataset has been misinterpreted in key methodological papers, because data were interpreted from ordinations alone, with no consideration of plots of the raw data. [ABSTRACT FROM AUTHOR]

Introduces articles in the October 2000 issue of the journal 'Australian Ecology.' Ecology and management of environmental weeds and Australia and New Zealand; Diversity of habitats invaded by environmental weeds; Value of exploratory and long-term studies; Interactions between environmental weeds and other biota.

In 2050, which aspects of ecosystem change will we regret not having measured? Long-term monitoring plays a crucial part in managing Australia's natural environment because time is a key factor underpinning changes in ecosystems. It is critical to start measuring key attributes of ecosystems - and the human and natural process affecting them - now, so that we can track the trajectory of change over time. This will facilitate informed choices about how to manage ecological changes (including interventions where they are required) and promote better understanding by 2050 of how particular ecosystems have been shaped over time. There will be considerable value in building on existing long-term monitoring programmes because this can add significantly to the temporal depth of information. The economic and social processes driving change in ecosystems are not identical in all ecosystems, so much of what is monitored (and the means by which it is monitored) will most likely target specific ecosystems or groups of ecosystems. To best understand the effects of ecosystem-specific threats and drivers, monitoring also will need to address the economic and social factors underpinning ecosystem-specific change. Therefore, robust assessments of the state of Australia's environment will be best achieved by reporting on the ecological performance of a representative sample of ecosystems over time. Political, policy and financial support to implement appropriate ecosystem-specific monitoring is a perennial problem. We suggest that the value of ecological monitoring will be demonstrable, when plot-based monitoring data make a unique and crucial contribution to Australia's ability to produce environmental accounts, environmental reports (e.g. the State of the Environment, State of the Forests) and to fulfilling reporting obligations under international agreements, such as the Convention on Biological Diversity. This paper suggests what must be done to meet Australia's ecological information needs by 2050. [ABSTRACT FROM AUTHOR]

The need to improve environmental management in Australia is urgent because human health, well-being and social stability all depend ultimately on maintenance of life-supporting ecological processes. Ecological science can inform this effort, but when issues are socially and economically complex the inclination is to wait for science to provide answers before acting. Increasingly, managers and policy-makers will be called on to use the present state of scientific knowledge to supply reasonable inferences for action based on imperfect knowledge. Hence, one challenge is to use existing ecological knowledge more effectively; a second is to tackle the critical unanswered ecological questions. This paper identifies areas of environmental management that are profoundly hindered by an inability of science to answer basic questions, in contrast to those areas where knowledge is not the major barrier to policy development and management. Of the 22 big questions identified herein, more than half are directly related to climate change. Several of the questions concern our limited understanding of the dynamics of marine systems. There is enough information already available to develop effective policy and management to address several significant ecological issues. We urge ecologists to make better use of existing knowledge in dialogue with policy-makers and land managers. Because the challenges are enormous, ecologists will increasingly be engaging a wide range of other disciplines to help identify pathways towards a sustainable future. [ABSTRACT FROM AUTHOR]

In arid and semiarid Australia fossorial vertebrates have been a major component of the soil biota mediating many fundamental landscape processes. However, many species such as the burrowing bettong ( Bettongia lesueur) have become seriously depleted following European pastoral settlement. As ‘landscape engineers’, they were responsible for creating and maintaining a high degree of surface heterogeneity that promoted a diverse and productive herbaceous understorey, particularly in ‘hard-red’ communities dominated by mulga ( Acacia aneura). While their regional extinction has had major impacts by contributing to desertification and loss of biodiversity, relict warrens ‘engineered’ by B. lesueur still remain in certain ecosystems and despite continual weathering, contribute significantly to herbage productivity and species diversity. This paper details the results obtained from a number of field studies aimed at determining the distribution of relict warrens at contrasting scales and their influence on landscape patch dynamics resulting from their impacts on soil nutrients, herbage composition and herbivory. Finally, the conservation implications following the continental extinction of this species and the resulting loss of fundamental ecosystem services, as well as cultural values, are discussed in the context of future re-introduction efforts. [ABSTRACT FROM AUTHOR]

Araucaria Forest expansion over grassland takes place under wet climate conditions and low disturbance and it is hypothesized that isolated trees established on grassland facilitate the establishment of forest woody species beneath their canopies. Forest with Araucaria angustifolia is a particular type of Brazilian Atlantic Forest and the main forest type on the highland plateau in south Brazil, often forming mosaics with natural Campos grassland. The objectives of this paper were to evaluate the role of isolated shrubs and trees as colonization sites for seedlings of Araucaria Forest woody species on grassland, to determine which species function as preferential nurse plants in the process and the importance of vertebrate diaspore dispersal on the structure of seedling communities beneath nurse plants. The study was conducted in São Francisco de Paula, Rio Grande do Sul State, where we sampled isolated shrubs and trees in natural grassland near Araucaria Forest edges. Seedlings were counted and identified, and seedling diaspore dispersal syndromes, size and colour were registered. We detected 11 woody species with a potential role in nucleating grassland colonization by forest species. Beneath the canopies of nurse plants more forest species seedlings were found compared with open field grassland and the seedlings had diaspores mostly dispersed by vertebrates. Also, more seedlings were found under the canopy of A. angustifolia than beneath other nurse plant species. We conclude that A. angustifolia trees established on grassland act as nurse plants, by attracting disperser birds that promote colonization of the site by other forest species seedlings, and that under low level of grassland disturbance, conservation of frugivorous vertebrate assemblages may increase forest expansion over natural grassland and also facilitate the regeneration of degraded forest areas. [ABSTRACT FROM AUTHOR]

The ecotone zone between epigean and hypogean environments has been delimited for two limestone caves using a new method proposed herein. The richness and the diversity of the ecotone, epigean and hypogean environments and their similarities have also been determined. The ecotones were delimited using a similarity matrix between the inner and outer sectors of each cave. The ecotone of Dona Rita's cave was estimated to be 12 m long and the ecotone of Retiro's cave 16 m. The richness (S) of arthropods in Dona Rita's cave was higher in the ecotone (S = 131), intermediate in the epigean environment (S = 75) and lower in the hypogean system (S = 45). The invertebrate diversity (H′) was lower in the hypogean environment (H′ = 2.89) and not statistically different between the epigean environment and the ecotone (H′ = 3.56 and H′ = 3.76, respectively). The richness in Retiro's cave was higher in the ecotone (S = 86), intermediate in the epigean environment (S = 39) and lower in the hypogean system (S = 12). The invertebrate diversity was lower in the hypogean environment (H′ = 0.48), intermediate in the ecotone (H′ = 3.02) and higher in the epigean region (H′ = 3.29). Species migration patterns, differential environmental barriers and determination of accidental versus trogloxenes/troglophylous species are topics that are primarily approached by establishing ecotone zones in caves. The aim of the present paper is to establish the delimitation of theses zones. [ABSTRACT FROM AUTHOR]

We explored the key issues that are most likely to influence any set of guiding principles for developing biodiversity monitoring programmes in Australia's rangelands. We defined the Australian rangelands and came up with an overview of their climate extremes, land-use pressures and biodiversity loss, and then focussed on issues underpinning the design phase of any monitoring programme. Using Noss's 1990 framework of compositional, structural and functional attributes of biodiversity and its new revisions by others, we showed how the elusive, abstract concept of biodiversity can be used to identify many measurable attributes that can form a minimum and necessary set of indicators for any biodiversity monitoring task. We then described the steps in the monitoring process, with a particular focus on the reasons for monitoring biodiversity as they strongly influence the selection of indicators. We concluded by compiling a table of key issues as background information for developing guiding principles (Table 4). The list is by no means an exhaustive list for the design phase but it does indicate that considerable attention needs to be given to this phase when developing monitoring programmes. We have intentionally not addressed the equally important issues associated with the planning and delivery phases of developing a monitoring programme, as Wallace et al. and Watson and Novelly cover these in their papers in the present issue of Austral Ecology. [ABSTRACT FROM AUTHOR]

Abstract The species saturation hypothesis in ground-dwelling ant communities was tested, the relationship between local and regional species richness was studied and the possible processes involved in this relationship were evaluated in the present paper. To describe the relationship between local and regional species richness, the ground-dwelling ant fauna of 10 forest remnants was sampled, using 10 1 m2 quadrats in each remnant. The ants were extracted from the litter by using Winkler sacs. Using regression analyses, an asymptotic pattern between local and regional species richness was detected. This saturated pattern may be related to three processes: (i) high interspecific competition; (ii) habitat species specialization; or (iii) stochastic equilibrium. It is concluded that non-interactive processes, such as stochastic equilibrium and habitat specialization may act as factors regulating species richness in this community. The predominance of locally restricted species, in all sampled remnants, seems to indicate the occurrence of a high degree of habitat specialization by the ant species. This result is evidence for the hypothesis that community saturation has been generated by non-interactive processes. Although ants are frequently described as highly interactive, it is possible that interspecific competition is not important in the structuring of ground-dwelling ant communities. [ABSTRACT FROM AUTHOR]

Abstract Hypothesis-testing methods for multivariate data are needed to make rigorous probability statements about the effects of factors and their interactions in experiments. Analysis of variance is particularly powerful for the analysis of univariate data. The traditional multivariate analogues, however, are too stringent in their assumptions for most ecological multivariate data sets. Non-parametric methods, based on permutation tests, are preferable. This paper describes a new non-parametric method for multivariate analysis of variance, after McArdle and Anderson (in press). It is given here, with several applications in ecology, to provide an alternative and perhaps more intuitive formulation for ANOVA (based on sums of squared distances) to complement the description provided by McArdle and Anderson (in press) for the analysis of any linear model. It is an improvement on previous non-parametric methods because it allows a direct additive partitioning of variation for complex models. It does this while maintaining the flexibility and lack of formal assumptions of other non-parametric methods. The test-statistic is a multivariate analogue to Fisher’s F-ratio and is calculated directly from any symmetric distance or dissimilarity matrix. P-values are then obtained using permutations. Some examples of the method are given for tests involving several factors, including factorial and hierarchical (nested) designs and tests of interactions. [ABSTRACT FROM AUTHOR]

Larvae of many anuran taxa display strong behavioural responses to chemical cues, including alarm signals from injured conspecific tadpoles. We exposed tadpoles and metamorphs from an Australian population of the invasive cane toad ( Chaunus[ Bufo] marinus) to a range of chemical stimuli and quantified their responses both in the laboratory and in the field. Filtered fluids containing scent cues from crushed conspecifics elicited strong avoidance from tadpoles, whereas other cues (e.g. scent of food, of native-range fish or urodele predators, and thermal stimuli) did not. Apparent aggregation of tadpoles in response to scent cues proved to be an artifact of tank design, and was an indirect consequence of avoidance of those cues. Field trials confirmed that free-ranging toad tadpoles and metamorphs avoided chemical cues from crushed conspecifics, suggesting that the chemicals inducing this response might provide an opportunity to develop targeted control methods for this invasive species. [ABSTRACT FROM AUTHOR]

Understanding the factors that influence the trade‐off between flowering and clonal growth in angiosperms is of great interest to botanists, plant ecologists and evolutionary biologists. Being able, ultimately, to manipulate these factors has potentially wide‐ranging applications in conservation biology, horticulture and agriculture. A rare, native Australian species, Melaleuca deanei, displays a low frequency of flowering and failed seedling recruitment, with persistence and expansion in the field predominantly via clonal root suckering. A decade of studies into its reproductive biology and ecology reveal both genetic and environmental factors reducing sexual success within its populations. Five factors influencing the trade‐off from sexual reproduction to clonal propagation are distilled and discussed in this work: 1. environmental constraint on sexual success; 2. small population size/low mate availability; 3. an obligate outcrossing breeding system; 4. somatic mutations in older clones; and 5. phylogenetic constraint. The work is potentially informative to the life cycles and management of other clonal angiosperms, be they rare and endangered; highly fecund weedy species; or economically important species. Methods to test each factor in future studies are proposed. [ABSTRACT FROM AUTHOR]

The cover page of the journal "Austral Ecology," is presented.

Vegetation restoration is a globally important form of management intervention designed to both remediate degraded land and to restore biodiversity. Using a 15‐year controlled experimental study in endangered Australian temperate woodlands, we quantified the response of bird biota to vegetation enhancement leading to the re‐establishment of an understorey, an increase in woodland patch size, or a combination of both. Our empirical results were characterized by marked variation in species richness and in the response of individual species to both time since enhancement and type of enhancement. For example, overall bird species richness initially responded negatively to enhancements but the effects were mitigated over time. Similar responses were identified for individual species such as the Rufous Songlark (Megalurus mathewsii). In the case of the Noisy Miner (Manorina melanocephala), responses to enhancement were negative and remained so over time. Conversely, the White‐plumed Honeyeater (Ptilotula penicillata), Yellow‐rumped Thornbill (Acanthiza chrysorrhoa) and Superb Fairy‐wren (Malarus cyaneus) responded positively to enhancements. We also found evidence for variable responses to the kind of enhancement with some species responding to increased woodland patch size (e.g. Yellow‐rumped Thornbill), others to a combination of enhancements (e.g. White‐plumed Honeyeater), whereas yet others were agnostic to the kind of intervention that was implemented (e.g. Noisy Miner). Positive effects of enhancement were often time lagged for 6–8 years following instigation of underplanting and/or increases in woodland patch size. The negative effects of patch enhancement on the Noisy Miner indicate that underplanting and/or increases in woodland patch size may represent ways in which the impacts on other bird taxa of this despotic, hyper‐aggressive species might be mitigated. [ABSTRACT FROM AUTHOR]

In the face of massive human impacts upon the environment, a prevailing attitude among Australian ecologists seems to have become one of pessimism. The essay explores the consequences of this stance. Pessimism arises understandably from personal values favouring care for the natural world under conditions of rapid global change. Expression of such values is in no way illegitimate; pessimism is as justifiable a perspective as is optimism when interpreting ecology. Examples are mentioned of areas of Australian ecology where pessimism does not predominate, and where the ecological changes being wrought by the Anthropocene are accepted. But, the predominance of gloom can cause ecologists to flirt with exaggeration and with misanthropy, and perversely it can cause them to strive to prevent ecological change even though the discipline is rooted in the reality of flux. Most profoundly, it causes many citizens to switch off: gloom has limited capacity to motivate, whereas hope is the elixir of action. Because of predominant negativity, we risk losing the confidence of society. The solution is for the discipline to develop more diverse strands of interpretation, characterized by more equal doses of acceptance and hope. By balancing dejection, ecology may achieve the efficacy in debate and decision-making that it warrants in these challenging times. [ABSTRACT FROM AUTHOR]

Monarch butterfly ( D anaus plexippus) populations are in decline in agricultural landscapes, in which genetically modified crops that are resistant to herbicides (' Roundup Ready') have resulted in the decimation of milkweed ( A sclepias spp.) hosts over large areas due to the increased use of glyphosate. Movement is the key ecological process linking individual fitness traits to the utilization of sparse resources distributed across landscapes with emergent population level consequences. Often, movement ecology is highly simplified or even abstracted into a simple rate of flow between populations (i.e. a metapopulation) separated by a hostile 'matrix'. Whereas, we can gain important insights into the population dynamic as a whole if we explore movement as an explicit, complex, behavioural process in which the matrix is not simply a void. We developed a spatially explicit individual-based model to describe host-seeking behaviour over the lifetime of a monarch butterfly, which utilizes hosts both aggregated in patches and scattered across the wider landscape as a substrate for laying eggs. We examine the simulated movement distances and spatial population distribution (eggs laid) as a result of different movement rules (directionality), perceptive distance (ability to find) and landscape configuration (how milkweed is distributed). This indicates the potential consequences of cleaning up the matrix (i.e. the obliteration of non-crop vegetation with Roundup) and changing habitat configurations at a landscape scale on individual movement behaviours and the emergent number of eggs laid, essentially the birth term in any population model. Our model generates movement distances of the order of 12 km commensurate with summer breeding monarchs and suggests that milkweed removal has reduced egg laying by up to 30%. We suggest possible amelioration strategies. [ABSTRACT FROM AUTHOR]

We studied how grazing intensity by small and mid-sized ungulate grazers varied with nutritional quality and grass species composition in wet oligotrophic tallgrass savanna of coastal northern Tanzania. Average grazing intensity was low (3-15% by cover), and most grass species were scarcely used by herbivores. Only two grasses, P anicum infestum and D igitaria milanjiana, had nitrogen and phosphorus concentrations that were consistently above the minimum levels (e.g. nitrogen concentrations <7 mg g−1) required by the three commonest grazers, Bohor reedbuck, waterbuck and wildebeest. The best predictors of grazing intensity were cover of P. infestum (the most abundant grass, with a mean cover of 15%) and canopy height of ungrazed vegetation. Models did not contain separate predictors for nutritional quality, presumably because quality varied mainly at the grass species level and therefore was fully represented by the variable 'cover of P . infestum'. Given that the three grazers differed greatly in body size and muzzle width (parameters known to influence nutrient requirements and the ability of grazers to feed selectively at the smallest spatial scale), we expected there to be strong resource partitioning that would be detectable in terms of grazing strategies and feeding sites. However, apart from minor differences in canopy height, greenness and diameter of grazed patches (albeit consistent with our expectations), feeding stations of the three grazers were similar and strongly dominated by P . infestum. We conclude that the low quality of herbage in wet oligotrophic savannas restricts foraging choices, which produces a characteristic yet impoverished grazing community that exhibits only limited resource partitioning. [ABSTRACT FROM AUTHOR]

In this study, systematic variation in tree morphology across a rainfall gradient in Australia's tropical savanna biome and its implications for carbon stocks and dynamics were quantified. The aim was to support efforts to manage fire regimes to increase vegetative carbon stocks as a greenhouse gas mitigation strategy. The height of trees for a given trunk diameter declines with decreasing rainfall from 2000 to 300 mm and increasing dry season length across the Australian savanna biome. It is likely that increasing dry season length is the main driver of this decline rather declining rainfall per se. By taking account of the response of total basal area to rainfall and soil type, stand structure, and tree height and diameter relationships, the carbon stocks in live trees were estimated to decline from about 34 t ha−1 in the wetter savannas to 6 t ha−1 in the drier savannas. These values are broadly consistent with field-based estimates. Because of the declining ratio of height to trunk diameter, trees of a given diameter in drier regions will be more likely to be killed by fires of a given intensity than trees in wetter regions. Thus single fires of given intensity are likely to have a greater proportionate impact on live tree carbon stock in drier savannas, but a much greater absolute impact in wetter savannas due to the greater total carbon stock. Projected decreases in early wet season rainfall under climate change scenarios, despite projections of little change in total precipitation in northern Australia, may lead to decreased carbon stock in live trees through two mechanisms: a reduction in total basal area and decreases in tree height for given trunk diameters. [ABSTRACT FROM AUTHOR]

Bell miners ( M anorina melanophrys; Meliphagidae) are a highly social and very aggressive honeyeater. They are despotic and cooperate in the defence of their territories against other bird species, leading to the almost complete exclusion of other avifauna from miner-occupied regions. This study aimed to resolve some of the fine-scale effects of bell miner aggression on avian diversity both within and adjacent to colonies to determine the true impact of a colony on local avifaunal abundance. Three areas, distributed throughout the range of the bell miner, were surveyed across both non-breeding and breeding seasons to assess the temporal and spatial impacts of bell miner aggression on other bird species. Bell miner colonies were found to occupy very clearly defined areas and had the expected negative impact on avian diversity within their colony. The effects of bell miner colony presence on abundance and richness of avian species were found to cease at the colony boundary, with both recovering to normal levels immediately outside the bell miner colony. Whether bell miners were breeding or not, and irrespective of the amount of vegetation coverage, bell miner colonies were found to have relatively marginal impacts on avian richness and abundance. No impact of colony presence/absence was found on the richness or abundance of the avian species that dwell in the undergrowth, with some evidence that these species were actually more common at the colony edge. Our results demonstrate that the influence of bell miner colony presence upon avian biodiversity is restricted to the confines of the colony and does not radiate outwards into the surrounding habitat. Colony presence influences, therefore, have implications when considering the impact of bell miner behaviour on the diversity of insectivorous birds and processes, most notably the propagation of Bell Miner Associated Dieback. [ABSTRACT FROM AUTHOR]

In this study we examined the spatial and temporal variation in a population of the critically endangered golden sun moth S ynemon plana over four years in a conservation reserve in south-eastern Australia. We found golden sun moth spatial distribution and abundance dramatically declined from a peak in extent and abundance from 2008-2009 to 2011-2012 due to a shift from drought to above average rainfall. Autoregressive correlative models indicated that a northerly aspect and landscape position were key predictors of abundance over time, and golden sun moth distribution shifted from wet to dry locations in the landscape. We conclude that: our data provide a counterpoint to conclusions that golden sun moth has been known to persist in very small areas and suggest that distribution can change quite markedly (from large connected populations to small patches) at a local scale, and this will be due to dispersal and survivorship; the variability in the data may have implications for adequate detection of the species over time, especially when populations have contracted and species have a naturally restricted activity and breeding period; and long-term weather patterns and landscape configuration (aspect, wet or dry position) interact to significantly affect local distribution and abundance over time. This has implications for the species under global change; increased variability in rainfall, temperature, productivity and exotic pasture growth may all alter and interact to either reduce or enhance persistence of golden sun moth populations over time. [ABSTRACT FROM AUTHOR]

We used a conjoint analysis to reveal the preferences of experts with respect to plant attributes under three different restoration scenarios (high-level conservation, functional native vegetation, perennial native pasture) and to generate prioritized lists for restoration of grassy woodland species. Nineteen experts participated in the conjoint analysis. The sample comprised researchers and practitioners with local knowledge of grassy ecosystems. The survey involved repeated pairwise ranking of the relevance of attributes of seven ecological criteria. The relative weightings of the attributes were then used to generate the 50 top-ranked species for each of the three scenarios. Overall phosphorus tolerance was considered the most important criterion, followed by grazing tolerance. Species favoured for high-level conservation management included nutrient- and grazing-intolerant plants with narrower distributions and some species of threatened status. The two scenarios with histories of fertilization and varying levels of ongoing grazing were most similar in that their lists were dominated by graminoids and did not contain any shrubs or geophytes. The ranking of species provides an initial list that could be tailored to take into account specific site conditions and additional knowledge of species. This approach to the selection of species shows promise as either a repeatable process to select species for particular sites, or to generate a classification of species that could be used generically for a small number of common situations. [ABSTRACT FROM AUTHOR]

In this study we assessed the water transport strategies and the abundance of alien and native tree species at a regional scale in Córdoba Mountains, Central Argentina. The aims of this study were: (i) to analyse whether alien and native tree species show divergent water transport strategies; and (ii) to explore whether species abundances of alien and natives are associated with specific trait attributes. Eight alien species and 12 native species were recorded in 50 complete vascular plant vegetation relevés. Water transport strategies were assessed through the following functional traits: minimum leaf water potential, potential water content of wood, effective leaf area, leaf area per sapwood area and wood density. Also, resource use strategies were assessed throughout the measurement of specific leaf area. We found that alien species had a higher efficiency in water transport (i.e. higher minimum leaf water potential and lower wood density values) and faster resource acquisition and use (higher specific leaf area values) than native species. We did not find evidence suggesting that the relative abundance of species was associated to water transport strategies and faster resource acquisition and use. Alien species seem to differ from natives in specific functional attributes that are absent in the resident community and might allow aliens to use more resources and at a higher rate than native species. Finally, our results show the potential of a trait-based predictive framework for alien species, and the possible effects on ecosystem functions. [ABSTRACT FROM AUTHOR]

Accurate determination of the population density of key focal species is necessary for monitoring the success of management programs and ecosystem health across a wide range of contexts. Unfortunately, many key taxa are visually cryptic and thus difficult to count using traditional observation-based techniques. Bell miners ( M anorina melanophrys), are just such a species. They are widespread throughout south-eastern Australia, yet they are critical to monitor given their association and potential causal link to spreading vegetative dieback in this region. A new passive acoustic monitoring technique was trialled by testing its ability to determine population densities of bell miner colonies via counting the distinctive 'tink' vocalization of this species. This call was given at a constant rate per individual, and at a common amplitude across 10 colonies throughout the entire geographic range of the species. Theoretical sound transmission and playback trials through typical habitat determined that any bird within a 50-m radius of the recorders used would be louder than 70 dB, enabling this threshold amplitude to be used to determine the number of birds in a 50 m radius of the recorder. Field trials of the acoustic protocol versus human observers using traditional visual surveys found that passive acoustic monitoring was able to detect more individuals, using a less expensive protocol that drastically reduced the need for observer training or expertise. Sound therefore offers a reliable method for determining the density of this vocal, but visually cryptic species. We present methods for calibrating recording devices and detecting calls louder than species-specific thresholds using readily available freeware, enabling our methods to be easily adapted to census a variety of acoustically distinctive species, offering a more effective, yet lower cost and in our case more efficient census technique for surveying difficult species. [ABSTRACT FROM AUTHOR]

Metabolomics may be defined as the analysis of thousands of naturally occurring small molecules (metabolites) such as sugars, organic acids, amino acids and nucleotides that are the products of cellular metabolism. As such, it is essentially the study of the complete biochemical phenotype (or metabotype) of any biofluid, cell, tissue or indeed organism, at both the qualitative and quantitative level. Metabolic profiles are context dependent, and will change in response to environmental circumstances. Therefore, while the technique has primarily been used in biomedical research to date, it is also applicable to ecological investigations and shows great promise in measuring the impact of factors such as climate change, disease, food restriction, infection and parasite load. In this review we detail the history and background of metabolomics and discuss examples of previous and potential future metabolic studies and applications in ecological science. [ABSTRACT FROM AUTHOR]

African olive ( Olea europaea ssp. cuspidata) is a small evergreen tree which has become highly invasive at a landscape scale in the western Sydney and Hunter Valley regions of New South Wales, Australia. African olive invasion results in the formation of a dense and permanent mid-canopy in grassy woodland vegetation. We investigated the relationship between African olive and native species establishment, abundance and diversity, using field surveys and a manipulative shading experiment. There were 78% fewer native species beneath African olive canopy in the field compared to uninvaded woodland sites. The shading experiment showed that simulated dense African olive shade levels produced the lowest dry weight for the three native species studied, with simulated canopy edge light providing optimal conditions for the native shrub Bursaria spinosa and African olive. Dense African olive shade levels produced the highest mortality rate for native species; however, African olive was able to maintain an 88% survival rate under dense canopy shade. This study confirms the adaptability of African olive and its capacity to decrease native plant diversity and substantially modify native vegetation at the community level. [ABSTRACT FROM AUTHOR]

Landscape ecology emerged as a terrestrial discipline to evaluate the effect of spatial configuration of natural systems on ecological patterns. The advances in marine systems have been comparatively scarce perhaps as a consequence of a long-standing view about the greater dispersal potential of marine species and its effect on the spatial homogenization of marine landscapes. Herein we used an intertidal rocky system as a model to analyse the effect of landscape attributes on local species richness and composition. We evaluated the effect of patch area, landscape connectivity and salinity gradient on local species richness of macro-invertebrates, and the effect of geographic distance on species similarity. We sampled 19 rocky patches along the Uruguayan Atlantic coast one time during the spring of 2003. The relative contribution of the variables assessed on specific richness of sessile, mobile and total macrofauna was analysed with a stepwise multiple linear regression. For the mobile macrofaunal richness, we also incorporated the sessile macrofaunal richness as another independent variable. The effect of geographic distance on biological similarity was assessed by a Mantel test. We showed that landscape connectivity, as a descriptor of the average physical isolation of a biological community in the landscape, is an important factor explaining the community species richness for sessile macrofauna, what indirectly increases the mobile macrofaunal richness. The geographic distance between sites was negatively related to species similarity. We suggest that at the landscape scale, connectivity among sites can be important to understand the local structure of marine communities, particularly in rocky intertidal systems. Also the distance-decay of similarity in community composition provides a useful descriptor of how biological composition varies along a physical gradient. Our results contribute to reinforce the view that mesoscale connectivity (101–2 km) in coastal marine landscapes plays a more important role in local community structure than previously assumed. [ABSTRACT FROM AUTHOR]

Australian painted dragon lizards Ctenophorus pictus occur in three head colours (red, orange and yellow) that differ in their level of aggression (reds being most aggressive), hormone profile (reds having higher testosterone levels) and in their frequency in our study population over time. They are also polymorphic in bib colour; some males have a bright yellow area under the chin, while others lack this coloured area entirely. We show that red males with a bib are in better body condition than red males that lack a bib. This contrasts sharply to yellow males, in which males with a bib are in poorer condition than yellow males that lack a bib. Our analysis also shows that following exposure to a high percentage of red (more aggressive) neighbours, all males suffer a reduction in body condition, and importantly, males with a bib (regardless of their head colour) suffer a more severe loss of body condition than males that lack a bib. Finally, this condition loss is significantly higher for yellow bibbed males than for red bibbed males, suggesting that the cost of sporting a bib may be higher for them. Orange males showed a non-significant difference in condition between bib morphs. Our analysis also shows that bibbed yellow males (the morph with lower body condition), but no other morph category, declined significantly in their frequency between 2 years. [ABSTRACT FROM AUTHOR]

Eucalypt trees are in decline throughout urban landscapes of south western Australia. This study investigated the cause of decline in Eucalyptus marginata and Corymbia calophylla trees in parkland and compared water and nutrient relations with healthy trees in adjacent bushland in Perth, Western Australia. It was hypothesized that: (i) trees were drought stressed through competition for soil water by the vigorous turf; (ii) excessive uptake of nitrogen, because of fertilizer application to turf, caused toxicity; and/or (iii) micronutrient (Cu, Fe, Mn and/or Zn) deficit was induced by high-pH irrigation water applied to turf around parkland trees. Leaf water potential showed aseasonal variation in the irrigated parkland trees and foliar δ13C indicated that parkland trees generally had low water-use efficiency and were not drought stressed relative to bushland trees. Foliar N levels were not significantly different between parkland and bushland trees indicating that excess N uptake was not a factor in the decline. Foliar total Fe, ‘metabolically active’ Fe, Cu and Zn concentrations were not significantly different between parkland and bushland trees. Foliar manganese concentrations were indicative of deficiency and significantly lower in parkland trees (5–14 µg g−1) relative to bushland trees (22–35 µg g−1). It is concluded that application of alkaline irrigation water to the parkland site reduced the plant-availability of Mn; however, our study of only one parkland site does not allow us to generalize the results across other parklands. [ABSTRACT FROM AUTHOR]

The spatial organization of individuals, or groups of individuals, within a population can provide valuable information about social organization and population dynamics. We analysed the spatial distribution of nests of the sociable weaver ( Philetairus socius) on two farms in the Kalahari. Sociable weavers build large communal nests on big savannah trees, forming a pattern of trees with and without nests. We used two spatial statistics, Ripley's K and the pair correlation function, to describe characteristics of the point patterns over a range of distances. (i) At distances of 200 and 300 m, communal nests were clustered. (ii) At distances greater than 1000 m, communal nests were regularly distributed. These findings are independent of the spatial distribution of trees. Furthermore, we used Moran's I to analyse spatial autocorrelation of nest sizes. We expected negative autocorrelation because of competition between nests. But on both farms there was no significant autocorrelation of nest sizes for any distance class. The regular distribution observed at larger distances may indicate competition and/or territoriality among different nests, but the lack of spatial autocorrelation between nest sizes suggests that these interactions may happen between nest clusters rather than between single nests. This was confirmed by significant clustering of nests on small scales. We thus suggest, that colonies of P. socius consist of several nests on adjacent trees forming a cluster of subcolonies. The question why sociable weavers establish subcolonies instead of adding more chambers to the natal nest, could not simply be answered by limitation of nesting space. We suggest a strategy to avoid costs due to increasing colony size. [ABSTRACT FROM AUTHOR]

Hurricanes have visible and invisible effects on forests. The visible effects are dramatic, noticeable over the short-term and relatively well documented in the literature. Invisible effects are less understood as they require well-focused research both in the short- and long-term time scales. This review of the literature on hurricane effects focuses on the Neotropics and the temperate zone of North America. The material is organized according to a heuristic model that distinguishes between immediate effects (0 to 3 years), immediate responses (0 to 20 years), trajectories of responses (0 to 100 years) and long-term legacies (>100 years). It is suggested that the ecological role of hurricanes involves six principal effects: 1. they change the ecological space available to organisms; 2. they set organisms in motion; 3. they increase the heterogeneity of the landscape and the variability in ecosystem processes; 4. they rejuvenate the landscape and its ecosystems and redirect succession; 5. they shape forest structure, influence their species composition and diversity and regulate their function; and 6. they induce evolutionary change through natural selection and ecological creativity through self-organization. A new approach to hurricane research will study hurricanes at the same scale at which they operate (i.e., across latitudes and longitudes and over disturbed and undisturbed landscapes). This research will require networks of observation platforms located along expected hurricane paths to facilitate forest structure and functioning observations across gradients of hurricane frequency and intensity. This research will also require use of remote sensing and automated wireless technology, hardened to survive hurricane-strength winds and floods to assure real time measurements of the characteristics of hurricanes and ecosystem responses. No progress will be forthcoming in the understanding of hurricane effects if we do not learn to quantify objectively the energy dissipation of hurricanes on the full grid of affected forests as the hurricane passes over a landscape. [ABSTRACT FROM AUTHOR]

The existence of latitudinal gradients in species richness and their abundance is known for many free living organisms but few cases have been reported for parasitic diseases. In addition, asymmetries between the Northern and Southern Hemispheres in several characteristics may affect the distribution and diversity of species at all ecological levels. In this respect, we study the distribution of several genera of blood parasites infecting birds along a latitudinal gradient that includes the world's southernmost forests ecosystems. Birds were mist-netted and sampled for blood in localities across Chile ranging from 33°S to 55°S during the years 2003–06. Overall, 26 bird species were sampled and 27 parasite lineages were identified. The latter belonged to three genera: Plasmodium (8), Haemoproteus (8) and Leucocytozoon (11). We found a positive significant relationship between prevalence and latitude for Leucocytozoon lineages and a negative relationship for Haemoproteus, Plasmodium and mixed infections. However, we did not find a significant relationship between parasite diversity and latitude. We found 18 lineages infecting only one species of host, and 19 lineages appear in only one of the localities of sampling. This pattern implies that some parasite lineages may evolve in isolation in some species/localities. In addition, specificity at the host-family level was only found for Haemoproteus lineages infecting birds in the family Emberizidae. Individuals of the long distance migrant bird white-crested elaenia ( Elaenia albiceps), were found infected by the same parasite lineages in localities separated by 20° of latitude. Infections by these lineages were detected in other sedentary birds including juveniles and nestlings of different bird species. Therefore, long distance migrants are able to distort the presence of latitudinal gradients of diseases due to the potential role of migrants in spreading infections. Geographical gradients in prevalence of avian haematozoa differ between parasite genera and hemispheres, probably in relation to the existence of appropriate vector–parasite–host interactions. [ABSTRACT FROM AUTHOR]

Kin recognition has been demonstrated to play an important role in the social structure of a wide range of animals. Most studies to date have examined parent–offspring recognition only in species that provide offspring with direct parental care, however, there are several advantages to parent–offspring recognition even in the absence of direct parental care. In this study we investigated reciprocal mother–offspring recognition in the Australian scincid lizard Eulamprus heatwolei, a species that does not show direct parental care. We examined whether neonates could discriminate between their mothers and unrelated females, and whether females could discriminate between their offspring and unrelated neonates, via chemical cues, using retreat site selection experiments. We conducted trials when neonates were 1 and 4 weeks old to investigate whether responses are maintained as neonates age. We found that both neonates and mothers could discriminate between related and unrelated individuals when neonates were 1 week old. Mothers were more likely to take refuge under tiles treated with the odours of their own offspring, while neonates spent less time in areas treated with the odours of unrelated females. At 4 weeks of age, mothers no longer exhibited discriminatory behaviour between their offspring and unrelated neonates, while neonates were more likely to associate with the odour of any female over the odourless control. We hypothesize that reciprocal mother–offspring recognition in E. heatwolei reduces interference competition between mothers and their offspring and also may be important in habitat selection and territory establishment. [ABSTRACT FROM AUTHOR]

Invasive woody species frequently change the composition of the established vegetation and the properties of the soil under their canopies. Accordingly, invasion may well affect regenerative phases of the community, especially at the seed bank level, likely influencing community restoration. Pyracantha angustifolia (Rosaceae) is an invasive shrub in central Argentina that affects woody recruitment, particularly enhancing the recruitment of other exotic woody species. There is though no information regarding its effect on the soil seed bank within the invaded community. The present study was set up to gain further insight into the canopy effects of P. angustifolia. We aimed to assess whether the invasive shrub affects seed bank composition, richness and seed density as compared with the dominant native shrub Condalia montana (Rhamnaceae), and to relate the observed seed bank patterns with those of the established vegetation. We evaluated the composition of the germinable seed bank and the established vegetation under the canopy of 16 shrubs of P. angustifolia, 16 shrubs of C. montana, and in 16 control plots (10 m2) without shrub cover. The floristic composition of the seed bank differed among canopy treatments. However, seed bank richness did not differ significantly. There was an overall high seed density of exotic species throughout the study site, though exotic forbs showed significantly lower seed densities under the invasive shrub. Pyracantha angustifolia would not promote the incorporation of new species into the seed bank of the invaded community but rather favour the establishment of woody species that do not depend on seed banks. The absence of dominant woody species in the seed bank, the dominance of exotic forbs, and the high similarity between established exotic species and those present in the seed bank may surely affect community restoration following the main disturbances events observed in the region. [ABSTRACT FROM AUTHOR]

Masting, the intermittent and synchronous production of large seed crops, may result from either of two major processes: resource matching and economy of scale. Components of cone production in Araucaria araucana were partitioned among populations and trees to ascertain the existence of masting and the processes involved. Cone production data from seven populations were obtained during a 9-year period and seed gathering data were available for an 18-year time series from six sites in an area of more than 7600 km2. Araucaria araucana showed environmentally triggered, intermittent, moderately fluctuating, and highly regionally synchronous reproduction. The mean pairwise correlations of cones production among populations and seed gathering sites were 0.89 and 0.74, respectively, suggesting synchrony in reproduction. Among trees we observed a mean correlation of 0.74 with values ranging from 0.66 to 0.81 for the analysed populations. The existence of negative autocorrelation in seed production between year 0 and year −2 at the individual tree level suggests the presence of ‘switching’ or internal resource allocation, thus discarding the Resource Matching hypothesis. Mean coefficient of variation (CVp) among populations was moderate (0.95) and similar to the modal CVp values reported in the published reports. Mean CVi among individual trees was 1.16, suggesting a large number of equally and synchronously fluctuating trees, rather than a few largely fluctuating individuals. These results suggest that pollination efficiency and/or predator satiation hypotheses could be responsible for the masting cycles in this conifer. Ancillary data about limitation of airborne pollen dispersion and temporal variation in the amount of seeds per cone and about seed predator satiation, also support both proposed mechanisms. [ABSTRACT FROM AUTHOR]

We tested the hypothesis that providing high-quality food and water would increase reproduction, survival and population size in house mice living in a semi-arid cropping environment in the mallee region of western Victoria, Australia, where outbreaks of house mice ( Mus domesticus) occur irregularly. We employed a factorial design and applied treatments along internal fencelines (16 sites), adjacent to cropping areas, from November 2003 to July 2004. Population abundance was low during the experiment (0–26 mice per site), and the summer rainfall was below average. We confirmed that mice used the supplementary food and water through a reduction in weight of food containers over time and for water through the presence of Rhodamine B in blood samples and positive bands in whiskers. Abundant food was also available through grain spilt on the ground after harvest of the wheat and barley crops. There was some evidence of increased breeding on sites where water was added, but no effect of food or food and water in combination. Sites where free water was available had marginally higher populations over summer (∼2 more mice on average; P = 0.07). This difference was well below any biologically meaningful effect. Mice were 0.9 g heavier on sites where water was added ( P = 0.04), and were in better condition ( P = 0.03). The addition of high-quality food did not affect mouse population dynamics, and the addition of water resulted in only marginal responses for some demographic characteristics. We conclude that other factors appear to be important for limiting mouse population growth in summer and autumn. [ABSTRACT FROM AUTHOR]

The importance of disturbance for regulating the structure and diversity of grassy ecosystems is widely recognized, but disturbance-mediated interactions between grassland composition and grassland resilience, and consequent implications for conservation management, are less well documented. We established replicated burning, mowing and (non-livestock) grazing regimes in two contrasting grassy woodland remnants in south-eastern Australia, and monitored the dynamics and resilience of the matrix-forming tussock grasses, Poa sieberiana ( Poa) and Themeda australis ( Themeda) , over 12 years. Introduction of frequent burning to a Poa-dominated understorey in a rarely burnt woodland enhanced dominance by Themeda, and conversely, reduced fire frequency in a frequently burnt Themeda grassland substantially increased Poa abundance . Burning was potentially detrimental in the Poa-dominated woodland, but sward resilience (recovery after the 2002 burn) increased as Themeda increased with repeated burning. By contrast, the Themeda grassland was resilient to 4- and 8-yearly burning, but biennial burning led to poor resilience and high tussock mortality under drought conditions. Contrary to other mesic grasslands, cessation of burning had not caused sward collapse by 14 years post-fire despite high litter accumulation, potentially due to compensatory growth of Poa, lower site productivity and drought. Biennial mowing without slash removal was similar to 4-yearly burning in effects, while exclusion from kangaroo and rabbit grazing significantly increased sward biomass and contributed to increased Poa cover and inflorescence production. We conclude that functional complementarity associated with mixed dominants enhances resilience to variable disturbance regimes, and that below certain thresholds of abundance of each dominant, this resilience declines. Conservation management of Themeda–Poa ecosystems should thus aim to maintain an effective balance of these dominants. [ABSTRACT FROM AUTHOR]

Establishing what are the underlying causes of species range limits is of fundamental interest in ecology. We followed the fate of individually mapped plants of three endemic New Zealand high-alpine species of Myosotis, over a period of 9 years. The species provide contrasts in their geographical range and their demography. Myosotis oreophila Petrie is rare and extremely localized ( c. 0.5 ha extent), Myosotis cheesemanii Petrie is regionally endemic, and Myosotis pulvinaris Hook. f. is more widespread. All three occur on the Dunstan Mountains, Central Otago, South Island, New Zealand within a 1-km radius, and individual plants were followed in four permanent plots. The three species differed in their longevity and in population variability, with the most widespread species ( M. pulvinaris) having the lowest survival (61% per year), the fewest old plants (only 3% of plants present in 1993 surviving until 2001), no increase in survival rates with age, and the most variability in total numbers across years. Both of the rare species, M. oreophila and M. cheesemanii, had higher survival (75% and 88%, respectively, per year) especially for older plants, many older plants (20% and 59%, respectively, of 1993 plants surviving until 2001), and lower variability in total numbers across years. These results are consistent with other studies showing that rare plant species tend to have higher inertia than more common congeners. The range limits of M. oreophila showed a high level of spatial constancy on a scale of metres over the 9 years, despite 80% turnover in plants during that time. The M. oreophila population showed lower mean densities of plants near to the population boundaries, identical age-specific survival rates, but lower flowering probabilities, than the core of the population. We were unable to detect any abiotic differences between inside and outside the M. oreophila range in terms of topography, soil parent materials, microclimate or through manipulation of snow cover. Disturbance may be a factor affecting the distribution of M. cheesemanii but limiting factors for M. oreophila and M. pulvinaris are likely to be biotic (competition, seed limitation, dispersal capacity) and/or historic. Further experimentation is recommended. [ABSTRACT FROM AUTHOR]

There is less certainty about the impact of climate change on tropical rainforests than on temperate forests because of the comparative lack of background data and because few large scale experiments have been, and are being, carried out in tropical rainforests. Many of the factors critical to the future of tropical rainforests concern canopies, the key processes that take place there, and the roles and interactions of canopy biodiversity. In particular there are almost no data on how forest canopies and processes are changing with increased carbon dioxide levels. The implications of elevated carbon dioxide, climatic stress and related changes in water-use efficiency, nutrient availability and other such changes are discussed particularly with references to Australia's tropical rainforests. [ABSTRACT FROM AUTHOR]

We describe extraordinary aspects of the feeding ecology of the austral parakeet, Enicognathus ferrugineus – the most southerly distributed psittacid in the world – that allow this endemic species to inhabit and become a common bird in relatively species-poor temperate and subantarctic Nothofagus forests of South America. We used two sources of information to analyse temporal and spatial dietary changes of austral parakeets in subalpine forests near Lake Distric of southern Argentina: (i) relative abundance of parakeet foraging on the forest floor along an altitudinal transect from 1000 to 1420 m; and (ii) faeces analyses of seasonal collections. Austral parakeets largely relied on a protein-rich pollen-based spring – early summer diet by destructively harvesting large quantities of wind-pollinated Nothofagus pumilioflowers and efficiently emptying pollen grains – specializations previously described only in pollinating nectarivorous vertebrates. Pollen emptying rates ( c. 65%) were the highest reported for psittacids and among the highest for vertebrates in general. Parakeets made extended use of short-lived N. pumilioflowers by tracking the altitudinal shifts in flowering phenology. Additionally, parakeets complemented their diet with carbohydrates from N. pumilio insect exudates. By late summer, parakeets switched to a lipid-rich diet based on N. pumilio seeds. This resource remained available through mid-autumn because parakeets also followed in altitude the phenological delays in fruiting. In winter, parakeets fed on N. pumilio parasitic Misodendrum mistletoe buds and leaves and Cyttaria sp. parasitic canopy fungi. These results suggest that stringent food availability in these relatively high latitudes may have led to behavioural and physiological specializations of austral parakeets to obtain year-round food resources efficiently from Nothofagus trees. [ABSTRACT FROM AUTHOR]

We report the composition of terrestrial, intertidal and shallow sublittoral faunal communities at sites around Rothera Research Station, Adelaide Island, Antarctic Peninsula. We examined primary hypotheses that the marine environment will have considerably higher species richness, biomass and abundance than the terrestrial, and that both will be greater than that found in the intertidal. We also compared ages and sizes of individuals of selected marine taxa between intertidal and subtidal zones to test the hypothesis that animals in a more stressed environment (intertidal) would be smaller and shorter lived. Species richness of intertidal and subtidal communities was found to be similar, with considerable overlap in composition. However, terrestrial communities showed no overlap with the intertidal, differing from previous reports, particularly from further north on the Antarctic Peninsula and Scotia Arc. Faunal biomass was variable but highest in the sublittoral. While terrestrial communities were depauperate with low biomass they displayed the highest overall abundance, with a mean of over 3 × 105 individuals per square metre. No significant differences in ages of intertidal and subtidal individuals of the same species were found, with bryozoan colonies of up to 4 years of age being present in the intertidal. In contrast with expectation and the limited existing literature we conclude that, while the Antarctic intertidal zone is clearly a suboptimal and highly stressful habitat, its faunal community can be well established and relatively diverse, and is not limited to short-term opportunists or waifs and strays. [ABSTRACT FROM AUTHOR]

Recolonization patterns of a tall-tussock grassland differ between low-frequency and high-intensity fires. A series of laboratory and field experiments were performed on the seed bank and on seeds of the main colonizing species ( Carduus acanthoides, Cirsium vulgare, Lotus glaber) to determine and compare the effects of fire frequency and fire intensity on their recolonization potential. Seed-bank size of colonizing species did not show a significant variation with contrasting fire frequencies, so overall interval-dependent effects do not seem to affect their propagule pool at the time of fire. However, frequency of fire modified the proportion of viable seeds and their dormancy state according to species. Accumulated emergence from experimentally buried soft-seeds of Lotus was lower after high-intensity fires (following wind direction) than after back-fires (against wind direction), but no significant effects of fire-front direction on seedling emergence were observed for hard-seeds of Lotus nor Carduus and Cirsium. Seedling emergence from buried seeds of Cirsium was increased with doubling fuel loads, particularly from deepen soil layers, where Cirsium had most of their viable seeds after a low frequency of fire. Emergence from hard-seeds of Lotus was less promoted than Cirsium by doubling fuel loads, and according to analysis of excavated seedlings, it was completely inhibited from upper soil layers of the seed bank. Integration of species-specific and burial depth-specific responses of Cirsium and Lotus seeds according to fuel load, vertical distribution of the seed banks, seed dormant states and mean emergence depths, resulted in expected emergence values which agree with their previously observed patterns of recolonization. Thus, event-dependent mechanisms had a better predictive value on recolonization success of the studied species than the observed cumulative effects of fire history on their seed-bank size. [ABSTRACT FROM AUTHOR]

Despite outnumbering their temperate counterparts, tropical snake species have been poorly studied. Yet, the few tropical species that have been studied show a variety of behavioural traits beyond those described in temperate species. Here we reveal both age and sexual differences in the movements of tropical green pythons ( Morelia viridis: Pythonidae). We radio-tracked 27 individuals (17 females and 10 males) for up to 18 months, locating individuals during both the day and night. The home range size for adult females (mean ± SE of 6.21 ± 1.85 ha) was correlated with snout–vent length. Neither adult males nor juveniles had a stable home range. Adult females had stable home ranges that overlapped considerably with those of other females and yellow individuals. Multiple radio-tracked adult males passed through the territory of radio-tracked adult females during the study. Females of all sizes were more likely to change position each day than males. There were no differences between the sexes or size categories in the distances moved in most months, although the variation in movement distances was higher in the dry season than during the wet season. In the wet season (January–March) movement distances increased and these were size- and sex-related. This increased activity may be associated with mate searching. Males of M. viridis may maximize their rate of encountering mature females by roaming rather than maintaining a home range. Juvenile green pythons moved distances equal to adult snakes in most months despite their comparatively small size. [ABSTRACT FROM AUTHOR]

Risk assessment systems for introduced species are being developed and applied globally, but methods for rigorously evaluating them are still in their infancy. We explore classification and regression tree models as an alternative to the current Australian Weed Risk Assessment system, and demonstrate how the performance of screening tests for unwanted alien species may be quantitatively compared using receiver operating characteristic (ROC) curve analysis. The optimal classification tree model for predicting weediness included just four out of a possible 44 attributes of introduced plants examined, namely: (i) intentional human dispersal of propagules; (ii) evidence of naturalization beyond native range; (iii) evidence of being a weed elsewhere; and (iv) a high level of domestication. Intentional human dispersal of propagules in combination with evidence of naturalization beyond a plants native range led to the strongest prediction of weediness. A high level of domestication in combination with no evidence of naturalization mitigated the likelihood of an introduced plant becoming a weed resulting from intentional human dispersal of propagules. Unlikely intentional human dispersal of propagules combined with no evidence of being a weed elsewhere led to the lowest predicted probability of weediness. The failure to include intrinsic plant attributes in the model suggests that either these attributes are not useful general predictors of weediness, or data and analysis were inadequate to elucidate the underlying relationship(s). This concurs with the historical pessimism that we will ever be able to accurately predict invasive plants. Given the apparent importance of propagule pressure (the number of individuals of an species released), future attempts at evaluating screening model performance for identifying unwanted plants need to account for propagule pressure when collating and/or analysing datasets. The classification tree had a cross-validated sensitivity of 93.6% and specificity of 36.7%. Based on the area under the ROC curve, the performance of the classification tree in correctly classifying plants as weeds or non-weeds was slightly inferior (Area under ROC curve = 0.83 ± 0.021 (±SE)) to that of the current risk assessment system in use (Area under ROC curve = 0.89 ± 0.018 (±SE)), although requires many fewer questions to be answered. [ABSTRACT FROM AUTHOR]

Despite the enormous contribution of invertebrates to global biodiversity and ecosystem function, the patterns and causes of insect responses to tropical rainforest destruction and fragmentation remain poorly understood. We studied the responses of beetles to these factors in a fragmented upland rainforest landscape in north-east Queensland, Australia. Beetles were sampled using flight interception traps from six replicate sites in rainforest interior, rainforest edge, small rainforest remnants and pasture, interspersed across about 600 km2. Beetles from 10 family/subfamily groups were sorted to species. There were three major findings. First, converting rainforest into pasture has a very strong negative effect on beetle diversity and species composition. Very few beetle species were present in pasture and none of the most abundant species was more abundant in pasture than rainforest. Second, beetle assemblages appeared to respond to climate. Beetle species composition in drier rainforest habitats was different from that of moister rainforest and there were species unique to each rainforest type. Third, beetle species composition differed between small remnants and interior rainforest: drier-associated species were more abundant in small remnants, whereas wetter-associated species were more abundant in interiors. Edges tended to be intermediate. We argue that this pattern can be attributed to a fragmentation effect mediated by differences in microclimate rather than by floristic, structural, or area and isolation effects. [ABSTRACT FROM AUTHOR]

The genus Nothofagus in New Zealand and Australia exhibits strong mast seeding (i.e. highly variable seed crops between years). Seed crop variation is synchronized within and between species over large spatial scales, and results in greatly increased wind pollination efficiency which could provide a selective benefit favouring the maintenance of mast seeding. However, the null hypothesis (that plants simply match their reproductive effort to the variable resources available each year) has not been tested in Nothofagus. Here we use a 33-year dataset on seedfall and wood ring increments for 19 individual Nothofagus truncata trees at Orongorongo, New Zealand, to test for the presence of switching (exaggeration of seedfall variability by diverting resources into, then out of, reproduction). A generalized least squares model explained 40.7% of the variance in standardized ring widths, using six weather variables (absolute minimum temperatures in March (lag 0) April (lag 0 and lag 1), May (lag 0) and rainfall in November and February (lag 0) ) and seedfall. Seedfall had a negative relationship with the current year's ring widths even after controlling for all significant weather variables. This shows that switching is occurring in N. truncata within individuals among years, and therefore that masting in this species is the result of selective forces such as increased wind pollination efficiency. As this result has been demonstrated for very few masting species, we call for this test to be applied more widely. [ABSTRACT FROM AUTHOR]

Plant species vary widely in their average leaf lifespan (LL) and specific leaf area (SLA, leaf area per dry mass). The negative LL–SLA relationship commonly seen among species represents an important evolutionary trade-off, with higher SLA indicating greater potential for fast growth (higher rate of return on a given investment), but longer LL indicating a longer duration of the revenue stream from that investment. We investigated how these leaf-economic traits related to aggregate properties of the plant crown. Across 14 Australian sclerophyll shrub species, those with long LL accumulated more leaf mass and leaf area per unit ground area. Light attenuation through their canopies was more severe. Leaf accumulation and light attenuation were more weakly related to SLA than to LL. The greater accumulation of foliage in species with longer LL and lower SLA may counterbalance their generally lower photosynthetic rates and light-capture areas per gram of leaf. [ABSTRACT FROM AUTHOR]

Global climate warming is expected to cause systematic shifts in the distribution of species and consequently increase extinction risk. Conservation managers must be able to detect, measure and accurately predict range shifts in order to mitigate impacts on biodiversity. However, important responses to climate change may go unnoticed or be dismissed if we fail to collect sufficient baseline data and apply the most sensitive analytical tests. Here we use randomizations of a contemporary data set on rainforest birds of north-eastern Australia to quantify the sensitivity of three measures for assessing range shifts along altitudinal gradients. We find that smaller range shifts are detectable by analysing change in the mean altitude of presence records rather than upper or lower range boundaries. For a moderate survey effort of 96 surveys, measurements of change in the mean altitude of 34 species have the capacity to provide strong inference for a mean altitudinal range shift as small as 40 m across the species assemblage. We also show that range shifts measured at range boundaries can be potentially misleading when differences in sampling effort between contemporary and historical data sets are not taken into account. [ABSTRACT FROM AUTHOR]

All natural populations fluctuate in abundance and age structure through time; understanding why they do so is a critical step towards their effective management and conservation. However, the long-term data sets needed for such an understanding are rarely available, especially for tropical organisms. A 17-year capture-mark–recapture study yielded detailed information on the demography of water pythons ( Liasis fuscus) and their main prey, the dusky rat ( Rattus colletti), on the Adelaide River flood plain in tropical Australia. The link between annual rainfall patterns and rat demography was highly non-linear. Rat numbers were low during years with low and high rainfall at the end of the wet season (April). Numbers of both predators and prey fluctuated considerably among years. Annual fluctuations in rat numbers generated a corresponding variation in rates of female python reproduction, python body condition and survival. Although variation in recruitment, survival and prey abundance all had a significant impact on annual fluctuations in python numbers, our analyses suggest that recruitment constituted the main determinant in driving the population dynamics of these large tropical predators. In combination with our other studies on this system, the data show that population dynamics of the water python population is ultimately driven by annual variation in rainfall, mediated via shifts in prey availability. The water pythons and the dusky rats of the Adelaide River flood plain thus demonstrate an unusually clear and direct link between an abiotic factor (rainfall) and predator–prey population dynamics. [ABSTRACT FROM AUTHOR]