Austral Ecology最新文献

Fish-habitat associations are fundamental ecological relationships characterising marine community assembly. The strength of fish-habitat associations can be indicative of ecosystem resilience, making them important benchmarks for ecological monitoring. These relationships are relatively unknown in mesophotic (30–150 m) marine systems due to the constraints of sampling in deeper waters. We aimed to assess fish-habitat associations in two unstudied no-take National Park Zones in the recently established Abrolhos Marine Park, Western Australia. We used the first baited remote underwater stereo-video systems (stereo-BRUVs) in this area to quantify demersal fish and benthic habitats between 33 and 154 m depth and modelled associations among fish species, traits and environmental covariates using Hierarchical Modelling of Species Communities (HMSC). Significant evidence of species-environment, trait-environment, and species-species associations was identified which may influence local community assembly. Benthic habitats explained 62.4% of the modelled variation in fish abundance, and 7 of the 21 modelled species showed strong statistical relationships with habitat, particularly macroalgae. The modelled species-environment relationships enabled us to infer the distribution of a subset of fish species across these understudied no-take zones. This study demonstrates the potential of discrete opportunistic studies using stereo-BRUVs for investigating the key drivers of community assembly in mesophotic marine environments. Our findings emphasise the importance of ongoing efforts to map and monitor benthic habitats and bathymetry as influential drivers of higher order species distribution beyond the coastal zone.

Fire is an important factor influencing the evolution, structure and composition of Australia's native vegetation. Australia's many fire-adapted species regenerate en masse after fire, with a proliferation of new epicormic shoots and seedlings. Given Austropuccinia psidii (myrtle rust) mainly infects new growth, post-fire emergence of new epicormic shoots and seedlings is ideal for the development of the disease, leading to further loss of plants along with subsequent increase of fungal inoculum in the region. Extreme fire events across New South Wales and Queensland in 2019–2020 and subsequent vegetation regeneration across a wide area provided ideal conditions for disease epidemics. Surveys for myrtle rust were conducted across rainforest, coastal heath and woodland environments from south-eastern NSW to south-east Queensland 6–12 months post-fire. Myrtle rust was identified in all regions and ecosystems surveyed apart from areas in south-eastern NSW. Of the 73 Myrtaceae species surveyed in areas other than southern NSW, 44 were found with myrtle rust symptoms, ranging from small spots and limited damage to severe blighting, dieback and death of reshooting trees and seedlings. Monitoring plots were established for some of the more susceptible species, with monthly assessments conducted to determine impact levels and decline rates. The most severely impacted species were Rhodamnia rubescens and Uromyrtus australis, with infections of reshoots causing dieback. Infection of Melaleuca quinquenervia and M. nodosa reshoots and seedlings impeded recovery of populations, causing seedling and tree deaths and reducing flower set and subsequent seed production.

Translocations are increasingly used to restore populations, yet seldom are simultaneous over large climate gradients into different latitudes, and rarely consider both a host and its parasites. Tuatara (Sphenodon punctatus) is a long-lived reptile endemic to Aotearoa New Zealand (NZ). Once found throughout NZ, tuatara populations are now sustained on offshore islands and increased through translocation, including to pest-free sanctuaries. Here, we study the simultaneous translocations of adult tuatara to four mainland sanctuaries a decade following release, investigating populations established both north and south of the founding population that span nearly 1000 km in latitude. We compared changes in body condition and snout-vent length (SVL) of tuatara, and abundance of a host-specific, ectoparasitic tick for tuatara among sites, plus evidence for survival and emergence of the next generation of tuatara. We found a general increase in SVL and maintenance of body condition between release in 2012 and 2023 at all sites, with some differences between males and females. However, tuatara at some sites showed more growth and/or higher body condition by 2023, particularly correlating with site temperature. Although ticks persisted on founding tuatara, there were fewer ticks on the next generation and those at the southern site. Evidence for a second generation of tuatara was also weakest at the southern site. This study shows that long-distance translocations north and south of a source population can yield promising outcomes for survival and growth of a long-lived reptile in current climates, though with differences in outcomes among sites.

Tropical dry forests (TDFs) have been altered by anthropogenic disturbances, particularly deforestation for pastures creation, which impacts plant and animal composition, abundance, and ecological processes. This study examined the spatio-temporal variation of fruit-feeding butterfly assemblage along an environmental gradient (forest interior, transition zone, and pasture) in TDFs at “Serra da Jacobina”, a mountain range 220 km long in Brazil. Butterflies were collected using 234 baited traps across nine transects in both the dry and rainy seasons. A total of 1091 individuals belonging to 35 species of the Nymphalidae family were sampled. Butterfly composition did not differ between environments or seasons, but forests showed higher abundance and richness, which were positively related to tree density. Species richness peaked in the rainy season, though abundance remained consistent. Eight species served as habitat indicators, with Hamadryas februa being the strongest indicator of old-growth forests; showing highest abundance in the forest interior and decreasing towards the pasture. Conversely, two species (Hamadryas feronia and Callicore sorana) showed the opposite pattern, predominating in pastures. Changes in land cover and tree density were key factors influencing butterfly assemblages. Longer pasture rotation and the preservation of native and fruit trees can help maintain insect diversity and ecosystem services, including those provided by fruit-feeding butterflies.

Community ecology explores the organisation and functioning of species assemblages shaped by historical, environmental and biotic processes. This review introduces community distribution models (CDMs), which extend species distribution models (SDMs) to higher ecological levels. CDMs integrate three key processes: (1) dispersal constraints, (2) environmental filters and (3) biotic drivers, while also incorporating metacommunity paradigms to explain community patterns. The review synthesises factors influencing community composition and identifies how CDMs can improve biodiversity predictions. We highlight the importance of environmental variables, biotic interactions and species traits and critically assess current modelling limitations. Functional traits, rather than species alone, are proposed as a more effective basis for modelling community dynamics, particularly in the context of climate change and habitat degradation. Finally, we advocate for integrative approaches combining correlative and mechanistic models to better capture community assembly across scales. CDMs hold great potential to address key ecological challenges, such as climate change impacts and conservation prioritisation. By advancing methodological frameworks and incorporating metacommunity theory, CDMs can provide deeper insights into emergent community properties and guide effective conservation strategies.

Modelling the distribution of microendemic species presents significant challenges due to limited occurrence records and the coarse resolution of available bioclimatic data. This is particularly true for montane regions, which harbour high levels of endemism and environmental heterogeneity. In this study, we modelled the potential distribution of Brachycephalus pernix group toadlets to assess their range and identify key environmental drivers of their ecological niches. We applied two correlative modelling approaches—model-selection procedures using MaxEnt and Ensemble Small Models—incorporating a broad suite of environmental predictors beyond traditional bioclimatic variables. Our results highlight that Ensemble Small Models outperformed model-selection procedures (MaxEnt) in predicting suitable habitats for these microendemic species, yielding more spatially precise predictions centred in highland, montane and submontane regions. Suitability was strongly associated with environmental variables related to precipitation and moisture, which play a critical role in shaping the realised niche of the B. pernix group. The species exhibited niche conservatism, likely reflecting the retention of ancestral ecological preferences that facilitate persistence in montane environments. This supports the hypothesis that mountain ranges act as long-term refugia during climatic fluctuations. Importantly, models incorporating heterogeneous environmental data outperformed those using only bioclimatic variables, highlighting the value of accounting for topographic and climatic complexity when modelling narrow-range taxa. Despite identifying additional suitable habitats, many of these areas remain unprotected and are increasingly threatened by deforestation and land-use change. Our findings provide new insights into the ecological requirements and distribution dynamics of the B. pernix group and emphasise the urgent need for targeted conservation efforts to safeguard their specialised habitats and ensure long-term persistence.

Effective population monitoring programmes rely on identifying individual animals accurately and ethically without negatively impacting their natural behaviour and survival. This study aimed to determine if the chin scale patterns of the threatened yakka skink (Egernia rugosa) could be used to consistently identify individual skinks. We examined the pattern uniqueness by monitoring (1) juveniles within the same aggregation, (2) juveniles across aggregations and (3) all ages caught across all years. Finally, we trialled the utility of the process by testing 14 experienced and 14 inexperienced people to see if they could correctly identify recaptured lizards from different age cohorts and aggregations, and the timeliness of undertaking manual identification. We identified 377 individual skinks over the length of the study using their unique chin patterns. Juvenile skinks both from the same and different aggregations had unique chin patterns allowing individuals to be correctly identified. A total of 190 skinks (50.4%) were recaptured. Chin pattern stability was confirmed by the recapture of 76 sub-adult skinks between 2021 and 2023 during a period where the skinks had undergone a substantial increase in body size. Pattern stability was also recorded in 43 mature skinks that were recaptured over an extended period of 1–15 years (mean 4.9 years). Experienced and inexperienced volunteers successfully identified known individuals 96.5% and 97.6% of the time, respectively, and importantly, the level of experience did not influence the time required by participants to make an accurate identification. Natural chin scale pattern variation was shown to be an effective and efficient means to identify individuals of this species. Natural pattern variation should be considered a reliable alternative to more invasive reptile marking procedures (e.g., toe clipping) and for use with other reptiles with natural and stable scale pattern variation.

Australia's vast network of inland wetlands attracts thousands of waterbirds to congregate and breed during ‘boom’ periods of rainfall and productivity. Monitoring waterbird biodiversity predominantly relies on annual aerial and ground-based surveys, which may miss rare or elusive species of conservation importance. Environmental DNA (eDNA) metabarcoding is being increasingly used as a tool for rapid biodiversity assessments across a wide range of ecosystems. Before eDNA can be routinely applied to new ecosystems, assays need to be optimised to address several challenges, including primer bias, reference database limitations, and data curation strategies. Here, we used an eDNA assay to detect avian species at four inland wetlands in south-eastern Australia. We assessed the impact of filtering strategies on waterbird detection probabilities and compared results against historical observational survey records. Our eDNA assay identified up to 40% of waterbirds historically recorded at the sites. Waterbirds detected with eDNA included the elusive and endangered Australasian bittern, migratory species such as gull-billed tern and whiskered tern, and an introduced feral goose not previously recorded. Community composition varied with filtering and detection approaches, highlighting the importance of assessing the impact of data curation on species detection with respect to historical species records. This study demonstrates the potential for eDNA to be incorporated into waterbird monitoring programmes. Future research should prioritise improving reference databases and optimising field sampling protocols for these ecosystems.

Species interaction networks are expected to vary following temporal changes in the environment and the composition of the local community. However, there are still gaps in our knowledge about temporal variation in networks in tropical areas, where less variable climates are expected to produce more stable community structures over time. Here we describe a plant-hummingbird network in the Brazilian Campo Rupestre ecosystem and investigate multiscale temporal variation of interactions in this community as well as the possible mechanisms underlying the frequencies of species interactions. Plants visited by hummingbirds were observed monthly for a year and each species had morphology, phenology and nectar traits measured. During 624 h of observation we recorded nine hummingbird species visiting 47 plant species, amounting to 9015 visits to flowers. Most plants (28 species) were endemic to the Campo Rupestre and mostly visited by the also endemic hummingbird Augastes scutatus (the Hyacinth Visorbearer). The annual network was not nested but presented high modularity and intermediate specialisation. While the overall (annual) frequencies of interaction were primarily defined by morphological matching and phenological overlap, we found a remarkable temporal change in community structure over the year, with different processes underlying interactions among plants and hummingbirds at different seasons. The interaction pattern during the rainy season was more similar to the annual network than the dry season (when nectar sugar content and plant phenology were also important), with more links per species and lower specialisation. The higher importance of morphology to predict interactions during the rainy season suggests higher niche partitioning when more hummingbird species are present in the community. Our results exemplify the importance of considering the temporal dynamics of the community to advance the understanding of the processes defining species interactions over time in the tropics.