Reptiles are an important part of the vertebrate fauna in the temperate woodlands of south-eastern Australia. However, compared to birds and mammals, the long-term occurrence of reptiles across ...woodland growth types–old growth, regrowth, and replantings–remains poorly understood. Here, using 18-years of data gathered at 218 sites across 1.5 million hectares in New South Wales South West Slopes bioregion, we sought to quantify patterns of temporal change in reptile occurrence and determine if such changes varied between woodland growth types. Despite extensive sampling, almost 75% of our 6341 surveys produced no detections of reptiles. Significant survey effort exceeding 2000 surveys was needed over a prolonged period of time to record detections of 26 reptile species in our study area. Our analyses showed a temporal increase in estimated reptile species richness and abundance over 18 years. Such increases characterized all three vegetation structural types we surveyed. At the individual species level, we had sufficient data to construct models for five of the 26 species recorded. Three of these species were least commonly detected in replantings, whereas the remaining two were most often detected in replantings relative to old growth and regrowth woodland. We found evidence of a temporal increase in two skink species, a decline in one gecko species, and no change in the remaining two skink species. Although detections were consistently low, active searches were the best survey method, and we suggest using this method in habitats known to be hotspots for reptiles, such as rocky outcrops, if the aim is to maximize the number of individuals and species detected. Our findings highlight the value of all three broad vegetation structure types in contributing to woodland reptile biodiversity.
Extensive areas of the Earth's terrestrial surface have been subject to restoration, but how best to manage such restored areas has received relatively limited attention. Here, we quantify the ...effects of livestock grazing on bird and reptile biota within 61 restoration plantings in south‐eastern Australia. Using path analysis, we identified some of the mechanisms giving rise to differences in patterns of species richness and individual species occurrence between grazed and ungrazed plantings. Specifically, we found evidence of both: (1) indirect effects of grazing on various elements of biodiversity mediated through changes in vegetation condition (primarily the leaf litter layer), and (2) direct effects of grazing on biodiversity (irrespective of modification in vegetation cover attributes), possibly as a result of trampling by livestock. We also uncovered evidence of direct effects on bird and reptile biota of other planting attributes such as planting width and planting age. The results of our study suggest that the biodiversity benefits of restoration programs can be undermined by grazing, especially by uncontrolled grazing. We suggest that where the objective of vegetation restoration is to enhance biodiversity conservation, grazing within plantings should be limited or excluded.
Extinction risk of the world's freshwater mammals Sanders, Emmalie; Wassens, Skye; Michael, Damian R. ...
Conservation biology,
February 2024, 2024-02-00, 20240201, Volume:
38, Issue:
1
Journal Article
Peer reviewed
Open access
The continued loss of freshwater habitats poses a significant threat to global biodiversity. We reviewed the extinction risk of 166 freshwater aquatic and semiaquatic mammals—a group rarely ...documented as a collective. We used the International Union for the Conservation of Nature Red List of Threatened Species categories as of December 2021 to determine extinction risk. Extinction risk was then compared among taxonomic groups, geographic areas, and biological traits. Thirty percent of all freshwater mammals were listed as threatened. Decreasing population trends were common (44.0%), including a greater rate of decline (3.6% in 20 years) than for mammals or freshwater species as a whole. Aquatic freshwater mammals were at a greater risk of extinction than semiaquatic freshwater mammals (95% CI –7.20 to –1.11). Twenty‐nine species were data deficient or not evaluated. Large species (95% CI 0.01 to 0.03) with large dispersal distances (95% CI 0.03 to 0.15) had a higher risk of extinction than small species with small dispersal distances. The number of threatening processes associated with a species compounded their risk of extinction (95% CI 0.28 to 0.77). Hunting, land clearing for logging and agriculture, pollution, residential development, and habitat modification or destruction from dams and water management posed the greatest threats to these species. The basic life‐history traits of many species were poorly known, highlighting the need for more research. Conservation of freshwater mammals requires a host of management actions centered around increased protection of riparian areas and more conscientious water management to aid the recovery of threatened species.
Riesgo de extinción de los mamíferos de agua dulce
Resumen
La pérdida continua de hábitats de agua dulce representa una amenaza importante para la biodiversidad mundial. Analizamos el riesgo de extinción de 166 especies de mamíferos acuáticos y semiacuáticos de agua dulce—un grupo que se documenta pocas veces como colectivo. Usamos las categorías de la Lista Roja de Especies Amenazadas de la Unión Internacional para la Conservación de la Naturaleza de diciembre 2021 para determinar el riesgo de extinción. Después comparamos este riesgo entre grupos taxonómicos, áreas geográficas y caracteres biológicos. El 30% de los mamíferos de agua dulce están categorizados como amenazados. La declinación de las tendencias poblacionales fue común (44.0%), incluyendo una mayor tasa de declinación (3.6% en 20 años) que para los mamíferos o las especies de agua dulce como conjunto. Los mamíferos acuáticos de agua dulce se encuentran en mayor riesgo de extinción que los mamíferos semiacuáticos (95% IC ‐7.20 a ‐1.11). Veintinueve especies no contaban con suficientes datos o no estaban evaluadas. Las especies grandes (95% IC 0.01 a 0.03) con distancias de dispersión amplias (95% IC 0.03 a 0.15) tuvieron un mayor riesgo de extinción que las especies pequeñas con menores distancias de dispersión. El número de procesos amenazantes asociados a alguna especie agravó su riesgo de extinción (95% CI 0.28 a 0.77). Las principales amenazas para estas especies fueron la cacería, el desmonte de tierras para tala y agricultura, la contaminación, los desarrollos residenciales y la destrucción o modificación del hábitat causados por presas o manejo hidrológico. Se sabe poco sobre los caracteres básicos de la historia de vida de muchas especies, lo que destaca la necesidad de más investigación al respecto. La conservación de mamíferos de agua dulce requiere una serie de acciones gestoras centradas en el incremento de la protección de las áreas ribereñas y una gestión hidrológica más consciente para ayudar a la recuperación de las especies amenazadas.
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.
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
Artificial refuges are human‐made structures that aim to create safe places for animals to breed, hibernate, or take shelter in lieu of natural refuges. Artificial refuges are used across ...the globe to mitigate the impacts of a variety of threats on wildlife, such as habitat loss and degradation. However, there is little understanding of the science underpinning artificial refuges, and what comprises best practice for artificial refuge design and implementation for wildlife conservation. We address this gap by undertaking a systematic review of the current state of artificial refuge research for the conservation of wildlife. We identified 224 studies of artificial refuges being implemented in the field to conserve wildlife species. The current literature on artificial refuges is dominated by studies of arboreal species, primarily birds and bats. Threatening processes addressed by artificial refuges were biological resource use (26%), invasive or problematic species (20%), and agriculture (15%), yet few studies examined artificial refuges specifically for threatened (Vulnerable, Endangered, or Critically Endangered) species (7%). Studies often reported the characteristics of artificial refuges (i.e. refuge size, construction materials; 87%) and surrounding vegetation (35%), but fewer studies measured the thermal properties of artificial refuges (18%), predator activity (17%), or food availability (3%). Almost all studies measured occupancy of the artificial refuges by target species (98%), and over half measured breeding activity (54%), whereas fewer included more detailed measures of fitness, such as breeding productivity (34%) or animal body condition (4%). Evaluating the benefits and impacts of artificial refuges requires sound experimental design, but only 39% of studies compared artificial refuges to experimental controls, and only 10% of studies used a before‐after‐control‐impact (BACI) design. As a consequence, few studies of artificial refuges can determine their overall effect on individuals or populations. We outline a series of key steps in the design, implementation, and monitoring of artificial refuges that are required to avoid perverse outcomes and maximise the chances of achieving conservation objectives. This review highlights a clear need for increased rigour in studies of artificial refuges if they are to play an important role in wildlife conservation.
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.
Summary
Urban expansion is a major cause of land use change and presents a significant threat to biodiversity worldwide. Agricultural land is often acquired by local councils and developers to expand ...urban growth boundaries and establish new housing estates. However, many agricultural landscapes support high biodiversity values, especially farmlands that feature mosaics of native vegetation and keystone habitat such as hollow‐bearing trees. In south‐eastern Australia, many arboreal marsupials including the threatened Squirrel Glider (Petaurus norfolcensis) have populations within peri‐urban zones of expanding rural cities. A key challenge to planners, developers and conservation organisations is the need to maintain habitat for locally rare and threatened species as land undergoes changes in management. Critical to the sustainable development of peri‐urban landscapes is a thorough understanding of the distribution, habitat requirements and resources available to maintain and improve habitat for species dependent on limited resources such as tree cavities. In this management report, we present background information on an integrated research programme designed to evaluate potential impacts of urban development on fauna in the Albury Local Government Area, NSW. We mapped hollow‐bearing trees, erected nest boxes and monitored arboreal marsupials. Information presented in this report provides a blueprint for monitoring arboreal marsupials, including threatened species in other developing regions, and will assist the Albury‐Wodonga local governments in future planning of sustainable living environments.
Aim
After environmental disasters, species with large population losses may need urgent protection to prevent extinction and support recovery. Following the 2019–2020 Australian megafires, we ...estimated population losses and recovery in fire‐affected fauna, to inform conservation status assessments and management.
Location
Temperate and subtropical Australia.
Time period
2019–2030 and beyond.
Major taxa
Australian terrestrial and freshwater vertebrates; one invertebrate group.
Methods
From > 1,050 fire‐affected taxa, we selected 173 whose distributions substantially overlapped the fire extent. We estimated the proportion of each taxon’s distribution affected by fires, using fire severity and aquatic impact mapping, and new distribution mapping. Using expert elicitation informed by evidence of responses to previous wildfires, we estimated local population responses to fires of varying severity. We combined the spatial and elicitation data to estimate overall population loss and recovery trajectories, and thus indicate potential eligibility for listing as threatened, or uplisting, under Australian legislation.
Results
We estimate that the 2019–2020 Australian megafires caused, or contributed to, population declines that make 70–82 taxa eligible for listing as threatened; and another 21–27 taxa eligible for uplisting. If so‐listed, this represents a 22–26% increase in Australian statutory lists of threatened terrestrial and freshwater vertebrates and spiny crayfish, and uplisting for 8–10% of threatened taxa. Such changes would cause an abrupt worsening of underlying trajectories in vertebrates, as measured by Red List Indices. We predict that 54–88% of 173 assessed taxa will not recover to pre‐fire population size within 10 years/three generations.
Main conclusions
We suggest the 2019–2020 Australian megafires have worsened the conservation prospects for many species. Of the 91 taxa recommended for listing/uplisting consideration, 84 are now under formal review through national processes. Improving predictions about taxon vulnerability with empirical data on population responses, reducing the likelihood of future catastrophic events and mitigating their impacts on biodiversity, are critical.
Sampling of environmental DNA (eDNA) and high‐throughput sequencing is emerging as an effective biodiversity assessment method in aquatic systems and may have utility for biodiversity inventory in ...terrestrial environments. Rock pools (gnammas) on granite inselbergs support a rich community of aquatic organisms and are culturally important to Indigenous peoples worldwide. However, the application of eDNA to survey rock pool biodiversity are undocumented. In a collaborative study with traditional owners, we explore the application of eDNA metabarcoding and traditional sampling methods to document and compare species richness and composition of eukaryotes from 15 rock pools (pits and pans) on granite inselbergs in southeastern Australia. We detected 116 taxonomic units, 81 assignments from eDNA sequencing and 35 species (23 rotifers and 12 microcrustaceans) using microscopic analysis. eDNA detected a broad range of taxa not previously documented from rock pools in Australia, although significantly more zooplankton (rotifers and microcrustaceans) were detected under a microscope, including several rare species and two undescribed species of rotifer. Brachionus calyciflorus and B. angularis were the only rotifer species assigned to species level through eDNA sequencing and were detected using both methods. We found no significant difference in mean species richness between rock pool types; however, species composition differed significantly between pits and pans. This study highlights the value of using eDNA to document biodiversity of ephemeral aquatic habitats in terrestrial ecosystems but reveals the general lack of reference sequence data for microorganisms, underscoring the value of using traditional sampling and taxonomic assignment methods.
Environmental DNA sampling coupled with high‐throughput sequencing is increasingly recognized as a useful method for assessing biodiversity with potential applications in terrestrial environments. Rock pools on granite inselbergs support diverse aquatic communities, yet the application of eDNA to document their biodiversity is lacking. Through a collaborative study with Indigenous communities, we investigated the effectiveness of eDNA metabarcoding alongside traditional sampling methods in characterizing the species richness and composition of eukaryotes in 15 rock pools across southeastern Australia.
Abstract Despite being a central aspect of a species' ecology and having important conservation implications, the use of fine‐scale habitat features (microhabitats), and how they vary over time, are ...poorly known for most species. In this study, we leveraged 522 relocations of radio‐tracked mallee tree dragons ( Amphibolurus norrisi ) and painted dragons ( Ctenophorus pictus ) to investigate the effect of environmental and individual variables on microhabitat use. Mallee tree dragons were more likely to use trees on hot days and in the middle of the day (the hottest time of day), whereas shrub use was more likely on cool days and in the mornings. Painted dragons were more likely to use shrubs and grass trees on warmer days and during the middle of the day, whereas burrows were used during cooler days and in the mornings and afternoons. We expect these patterns represent animals moving from refuge resources, occupied during unsuitable thermal conditions, to microhabitats offering basking, foraging and social opportunities during periods of thermal optimum. Additionally, we found evidence of an ontogenetic shift, with larger mallee tree dragons favouring tree use and higher perches, suggesting a transition from shrub to tree use with age. Our findings underscore the need for diverse microhabitats to accommodate the thermoregulatory and ontogenetic requirements of lizards. These insights can inform conservation and habitat restoration efforts, ensuring the provision of essential microhabitats to support species persistence.
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