Search

Altered fire regimes and the increased frequency and/or severity of wildfires are significant issues for fire‐sensitive species. In the Austral summer of 2019/2020, Australia experienced one of the worst fire seasons in recorded history (known as the 2019/2020 megafires), affecting 12.6 million hectares of eastern Australia. The Endangered southern greater glider (Petauroides volans) inhabits large areas impacted by the 2019/2020 megafires. With increasing fire severity, frequency, and intensity, there is a need to understand where in the landscape southern greater gliders are most impacted by fire, and where the species is most likely to persist in fire‐affected landscapes. This is challenging given the lack of systematic data collected for this species. Maximum entropy modelling (Maxent) is a type of species distribution model with good predictive performance for presence‐only records. We used Maxent to model the distribution of the southern greater glider in the two years prior (2017–2019) and two years post (2020–2022) megafire across the East Gippsland region of Victoria, an area heavily affected by the 2019/2020 megafires. Whilst we found that the predicted short‐term area of occurrence of the southern greater glider remained relatively stable in the two years after megafire, a large area of marginal habitat was considerably reduced. We interpret this result as a potential contraction of suitable habitat where southern greater gliders may become isolated. Post fire, higher elevation areas and locations that experienced comparatively lower fire severity and a lower fire frequency had a higher predicted occurrence of the southern greater glider. Understanding the role of fire in species survival is essential for effective biodiversity conservation and management of species. More comprehensive and systematic monitoring in suitable and unsuitable areas will enhance our understanding of the distribution of the southern greater glider, including areas subject to wildfire. [ABSTRACT FROM AUTHOR]

Co-occurring species often overlap in their use of resources and can interact in complex ways. However, shifts in environmental conditions or resource availability can lead to changes in patterns of species co-occurrence, which may be exacerbated by global escalation of human disturbances to ecosystems, including conservation-directed interventions. We investigated the relative abundance and co-occurrence of two naturally sympatric mammal species following two forms of environmental disturbance: wildfire and introduced predator control. Using 14 years of abundance data from repeat surveys at long-term monitoring sites in south-eastern Australia, we examined the association between a marsupial, the common brushtail possum Trichosurus vulpecula, and a co-occurring native rodent, the bush rat Rattus fuscipes. We asked: In a fox-controlled environment, are the abundances of common brushtail possums and bush rats affected by environmental disturbance and each other's presence? Using Bayesian regression models, we tested hypotheses that the abundance of each species would vary with changes in environmental and disturbance variables, and that the negative association between bush rats and common brushtail possums was stronger than the association between bush rats and disturbance. Our analyses revealed that bush rat abundance varied greatly in relation to environmental and disturbance variables, whereas common brushtail possums showed relatively limited variation in response to the same variables. There was a negative association between common brushtail possums and bush rats, but this association was weaker than the initial decline and subsequent recovery of bush rats in response to wildfires. Using co-occurrence analysis, we can infer negative relationships in abundance between co-occurring species, but to understand the impacts of such associations, and plan appropriate conservation measures, we require more information on interactions between the species and environmental variables. Co-occurrence can be a powerful and novel method to diagnose threats to communities and understand changes in ecosystem dynamics. [ABSTRACT FROM AUTHOR]

Restoring structural elements of habitats and understanding how restoration interacts with environmental factors such as grazing management can be crucial for improving conservation outcomes in agricultural landscapes. Surface rock is a structural habitat type that is critical for a range of reptile species; yet, it is often poorly managed and protected.Using a Before/After, Control/Impact (BACI) design, we experimentally quantified the response of reptiles to surface rock restoration in an agricultural landscape, and tested whether its effects interacted with livestock grazing treatments to influence various reptile diversity measures. To implement our crossed factorial design, we added approximately 50 tonnes of rock and 1 km of grazing exclusion fencing across 10 sites in south‐eastern Australia.We found increases in the number of total reptile captures, total individuals and species richness when comparing rock addition plots to non‐rock plots. There was no significant overall grazing exclusion effect or interactive effect of grazing and rock treatment on reptile measures.Synthesis and applications. Our study provides experimental evidence that surface rock addition is an effective restoration method for reptiles in agricultural landscapes. We recommend that the addition of surface rock is prioritised as a restoration tool for reptiles, and that existing surface rock areas are protected from clearing. [ABSTRACT FROM AUTHOR]

Context: Understanding what characteristics influence retreat-site selection by fauna is critical for both habitat management and species conservation. Despite the documented ecological values of surface rocks, there is limited knowledge of the attributes of surface rock that contribute to their use in agricultural landscapes or during winter months when reptiles are brumating, activity patterns are reduced, and sheltering individuals are most vulnerable to disturbance. Objectives: We surveyed reptiles sheltering beneath surface rocks in grazing farms in south-eastern Australia to address two questions: (i) What landscape factors influence the occurrence of reptiles over austral winter? (ii) What physical and thermal factors influence retreat-site selection? Methods: We surveyed 14 sites, with three plots per site, stratified across a gradient of canopy cover. We measured landscape attributes of surveyed sites and thermal and physical characteristics of individual surface rocks to quantify relationships between the occurrence of reptiles in the landscape and the properties of retreats selected. Results: We found that relatively small patches of surface rock can support high reptile numbers, with density estimates up to of 208 individuals per hectare. Reptile abundance was positively associated with increased elevation and limited canopy cover. Reptiles selected smaller rocks with high surface area to volume ratio, were minimally embedded in the soil, and rocks supporting few invertebrates. Conclusions: Conserving cryptozoic reptiles in agricultural landscapes can be enhanced through the appropriate management and retention of surface rock. We discuss implications for reptile conservation and surface rock management in agricultural landscapes. [ABSTRACT FROM AUTHOR]

Large quantities of dead wood can be generated by disturbances such as wildfires. Dead trees created by disturbances play many critical ecological roles in forest ecosystems globally. The ability of deadwood to serve its ecological roles is contingent, in part, on the length of time trees remain standing following disturbance. Here, we briefly outline the results of a 10‐year study that aimed to quantify the rate of collapse of trees killed in a major wildfire in the wet ash forests of mainland south‐eastern Australia. We also quantified the factors associated with dead tree collapse. Our analyses revealed that 23% of 417 measured trees collapsed between 2011 and 2021. The most parsimonious model of the factors influencing tree collapse revealed a strong effect of diameter; smaller diameter trees were more likely to collapse over the 10 years of our study than larger diameter trees. In addition, trees in small and large patches were more likely to collapse than trees in contiguous forest (where there had been no logging in the surrounding area). If current rates of tree fall are maintained, then many of trees initially measured will have collapsed by 2030. Such losses of dead trees will have major negative effects on key values of ash‐type forests such as biodiversity conservation. [ABSTRACT FROM AUTHOR]

Reintroduction and translocation are widely employed actions in restoration ecology. The broad aim of these activities is to re‐establish populations in places where they formerly existed. However, the success of re‐establishment efforts in terms of responses to key ecosystem processes such as natural disturbances like fires has rarely been quantified. Using the iconic and endangered Australian Eastern Bristlebird (Dasyornis brachypterus) as a case study, we quantified associations with fire regime variables in an intact population (surveyed for 17 years) and a translocated population (surveyed for 10 years). Both populations occurred in a similar environment and were surveyed on an (almost) annual basis using the same field protocols. We found that both the intact population and the translocated population of the Eastern Bristlebird were associated with the same key fire regime variable, time since fire, in a broadly similar way. In addition, the probability of species persistence was found to lowest on recently burnt sites. We tentatively suggest that the translocation program has not only successfully re‐established a population of the Eastern Bristlebird but associations with (and resilience to) fire as a key ecological process are similar in both populations. On the basis of our findings, we recommend that in areas where the Eastern Bristlebird occurs prescribed fire management should focus on ensuring there are patches of unburnt vegetation within the fire footprint. This is especially important given the widespread wildfires that have recently occurred throughout south‐eastern Australia. [ABSTRACT FROM AUTHOR]