Austral Ecology最新文献

Natural regeneration in tropical open ecosystems has proved to be an effective mechanism for recovering degraded areas when considering the woody vegetation layer. However, little is known about the potential of the ground layer to recover after anthropogenic disturbances. Here, we aim to deepen the current understanding of community assembly in tropical open ecosystems by studying the natural regeneration potential in the Cerrado, with a focus on the ground layer. By inducing disturbance in conserved and degraded Cerrado grasslands, we tested the hypothesis that typical (native) Cerrado species colonise the disturbed patches primarily through vegetative propagation rather than by seed germination. Therefore, the vegetation would resemble the surrounding area instead of forming a novel species assembly. We induced disturbance by creating small gaps and monitored species colonisation strategies under both conditions. Non-native species dominated the degraded site, whereas the conserved site—an old-growth grassland—was dominated by native species. After 18 months (two reproductive seasons after the gaps opening), few native species colonised the degraded area, despite the removal of the non-native species in the gaps and the proximity to the conserved vegetation. Only exotic and ruderal species colonised the gaps in the degraded area, primarily through seed germination. Conversely, in the conserved area, the most common regeneration strategies were resprouting from deep and lateral underground structures (bud-banks) and stolon propagation. Therefore, we provide evidence that natural regeneration is dominated by vegetative propagation and resprouting in the Cerrado, with limited scope for native plants to colonise, even over short distances. Without a viable belowground bud-bank, restoring the Cerrado open ecosystems requires active techniques.

Invasive rodents are among the world's most damaging invasive species linked to declines and extinctions of many vertebrate and invertebrate species, especially in island ecosystems. However, despite a mainly herbivorous diet, their impacts on plant communities are less well known, with few studies in Australian ecosystems. We studied the potential impacts of high-density populations of invasive black rats (Rattus rattus) on the restoration of an endangered ecological community of sub-tropical rainforest on two small islands in southeastern Australia. We used two experiments to investigate rat impacts on two woody rainforest species, Hibiscus heterophyllus and Acacia maidenii, that are frequently used for successional planting in restoration. We hypothesised that, as black rats generally obtain a large amount of their diet from plants, they would rapidly damage Hibiscus and Acacia seedlings and consume Hibiscus seeds. We found that using cages to exclude black rats for 11–14 days had significant effects on herbivory of Hibiscus seedlings but not for Acacia seedlings. Hibiscus seedlings with no exclusion cage lost an average of 17% more leaves (1.83 of initial average 10.6 leaves per plant) when compared to caged seedlings. We also found that excluding rats reduced the number of Hibiscus seedlings damaged, although 50% of the damage was suspected to be caused by insects. Although only 4.5% of total Hibiscus seeds were removed during the 3-day experimental period, the night-time removal rate (mostly attributed to black rats) was 10 times more than that of other diurnal foragers. This rate of seed removal by black rats has the potential to contribute to poor restoration in rainforest but was lower than black rat consumption of seeds in other systems. We conclude that, in our system, black rats appear to have minimal potential impacts on these rainforest species, despite high rat densities, confirming the successful use of these species in restoration. However, being novel to the system, the additive effects of rats on seed loss over time warrant further investigation.

Tree ferns (order Cyatheales) are a key component of wet forests globally, providing critical forest understorey structure and ecosystem functions. Tree ferns may be impacted by ungulates in novel habitats, but the extent and severity of these impacts are often uncertain. We aimed to determine the impact of introduced deer on tree ferns in wet forests of south-eastern Australia. Using both broadscale deer abundance and impact surveys and targeted tree fern assessments, we surveyed browsing impacts on tree ferns at over 200 sites across a range of wet forest types in south-eastern Australia where deer are present. Tree fern species, plant height and estimates of foliage biomass removed by browsing were recorded for over 4500 individual tree ferns including 1871 Cyathea australis, 2622 Dicksonia antarctica and 41 Todea barbara. Browsing impacts on tree ferns were recorded at 96% of surveyed sites, with a third to a half of tree ferns typically impacted by browsing at each site. There were no differences in recorded impact between tree fern species. Browsing of tree ferns was strongly height dependent, regardless of species, and associated with indices of deer density. Tree ferns < 100 cm were often highly impacted (mean > 20% foliage browsed), with impact declining approximately linearly with height to 200 cm, typically low 200 to 300 cm, and absent thereafter. The widespread and in many cases severe browsing on tree ferns recorded can be largely attributable to introduced deer. These impacts potentially threaten tree fern populations and diminish the vegetation structure and ecosystem function of these wet forests. Management interventions to reduce deer populations in the wet forests of south-eastern Australia are critical to protect forest integrity and function.

Turban snails (known as Gugumbal in Gumbainggir Country) are bioculturally important Sea Country molluscs distributed throughout south-eastern Australia. Like most shallow water marine species, climate change is anticipated to result in poleward range shifts, or possibly even regional extinctions. Given the biocultural importance of Gugumbal, an understanding of how future climate change impacts is necessary to anticipate cultural and ecological implications associated with the redistribution of these species. We developed species distribution models to assess for climate-driven redistributions among three Gugumbal species, including Turbo militaris, Lunella torquata and Lunella undulata. Modelling under four IPCC future climate change scenarios and two future time points (RCP2.6, 4.5, 6.0 and 8.5, for 2050 and 2100) identified equatorward range edge contractions across all three species and poleward range edge expansion in two species, with the magnitude of anticipated range shifts being generally concomitant with increasing climate scenario severity. We discuss the ecological and cultural implications of the future redistribution of Gugumbal across the various Indigenous Sea Countries in south-eastern Australia.

Wild birds can provide essential benefits and cause significant harm in food production systems, commonly framed as ecosystem services and disservices, respectively. We conducted a systematic review of the literature on avian ecosystem services and disservices in horticultural systems, analysing 251 studies published between 1912 and 2023. Species richness and abundance were the most commonly used metrics. A total of 128 studies investigated ecosystem services, 109 addressed disservices, and only 22 considered both. Pest control (137 occurrences) and crop damage (120) were the dominant subjects within ecosystem services and disservices, respectively. However, crop damage was frequently reported without assessment, suggesting a confirmation bias towards birds as pests. The methods used to assess services and disservices were diverse, including species identification, damage and yield surveys, landscape analysis, experiments, published data, social surveys, laboratory techniques, and economic or ecological modelling. Despite this methodological diversity, most studies used only one or two approaches. Studies incorporating human-wildlife conflict were rare, despite their relevance for both conservation and horticultural management. This review reveals a bias towards studying avian contributions that are more easily measurable, such as pest control and crop damage, while more complex or less visible effects, such as pollination, disease control, or herbivore release, remain underexplored. As a result, birds' roles in horticultural systems are often understood in fragmented terms, potentially leading to ineffective or unjustified management decisions. A more holistic, species-focused, and integrative approach is needed to fully understand the trade-offs between ecosystem services and disservices. Such understanding is critical not only for enhancing the sustainability and productivity of food systems, but also for conserving wild birds in increasingly intensified agricultural landscapes.

Feral horses (Equus caballus) are listed as a Key Threatening Process (KTP) under federal and state conservation policies, leading to active state government management programs aimed at reducing feral horse populations in ecologically sensitive regions (Tables 1 and 2). Program and expert reporting shows benefits for water, vegetation, soil, waterbirds and native fish from horse removal in these systems (Rowland, Moore, and Walsh 2023; Just et al. 2025). The NSW Government's Kosciuszko Wild Horse Heritage Act 2018 diverges from the policies of other States, and conflicts with the NSW KTP listing, by mandating retention of 3000 horses in one third of Kosciuszko National Park. This is despite extensive scientific evidence of the environmental harm caused by feral horses in Kosciuszko National Park, across other alpine, subalpine and riverine regions (Figure 1), and in other ecosystems (Nimmo and Miller 2007; Driscoll et al. 2019; Stobo-Wilson et al. 2020).

Complete removal via culling of feral horses from threatened alpine and subalpine ecosystems, including peatlands and wetlands, is recommended (Beeton and Johnson 2019). Excluding horses from sensitive locations (e.g., through fencing), or using fertility control methods, is insufficient for preserving ecological function and connectivity of sensitive ecosystems such as alpine peatlands and wetlands (Driscoll et al. 2019; Hobbs and Hinds 2018).

Horse control must be coordinated with integrated fire and pest management strategies addressing other invasive herbivores and omnivores, weeds and invasive predators (Keith et al. 2022; Rowland, Walsh, et al. 2023). Restoration, including moss layer transfers and hydrological repair in peatlands, may reverse some damage and recover lost carbon storage capacity once horses are removed (Treby and Grover 2023).

Uncensored evidence-based communication of feral horse impacts by State agency staff, independent scientists and political leaders is essential to make the cost of inaction clear (Nimmo and Miller 2007). The evidence is unequivocal: feral horses present a significant ecological threat to Australia's alpine and subalpine environments. Legislation that supports effective feral horse control throughout national parks and other public land designated for conservation purposes must be in place.

The authors declare no conflicts of interest.

This study investigates the absence of non-indigenous sun coral Tubastraea in Guanabara Bay, Rio de Janeiro, despite its presence on nearby islands. Tubastraea corals are known for their high reproductive plasticity and resilience to varying environmental conditions. An ex-situ experiment was conducted in which colonies of Tubastraea aurea were exposed to a continuous flow of seawater sourced from Guanabara Bay. During the experiment, colonies developed a Stress-Induced Mucus Aggregate (SIMA) that progressively enveloped the polyps and was associated with marked tissue loss upon removal. This response is distinct from the coral's typical mucus secretion and is hypothesised to result from environmental stress-induced alterations in the associated microbiota. The influx of organic matter and pollutants likely promotes a shift toward pathogenic and anaerobic microbial communities, which may further impair tissue respiration and contribute to coral mortality. 16S rRNA gene sequencing identified four ecologically significant bacterial genera—Vibrio, Pseudoalteromonas, Alcanivorax and Shewanella—commonly found in marine systems. These organisms demonstrate functional duality in coral microbiomes, simultaneously influencing both biofilm-mediated community assembly and disease dynamics. Their context-dependent roles markedly affect coral health outcomes under environmental stress regimes, highlighting their importance in reef ecosystem resilience. These findings suggest that microbial community dynamics in highly disturbed environments may play a key role in limiting the establishment and persistence of T. aurea in Guanabara Bay. Future research will focus on elucidating the role of physico-chemical water parameters, sedimentation and microbial community shifts in the survival of Tubastraea corals in Guanabara Bay.