ORCID Profile
0000-0003-2212-2562
Current Organisation
BirdLife Australia
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Informa UK Limited
Date: 03-07-2023
Publisher: Wiley
Date: 07-2023
DOI: 10.1002/ECE3.10331
Abstract: Detection is essential to studying and monitoring wild animals however, detection is challenging for small endotherms that are nocturnal or best detected at night. Techniques such as trapping or spotlighting disturb focal species, and the effectiveness of spotlighting can be limited for cryptic species, resulting in low detection rates that hinder our ability to monitor and study some endotherms at night. Thermal scanners detect infrared wavelengths not otherwise visible to humans. With improvements in equipment size and cost, thermal scanners have emerged as a valuable tool for passive detection of endotherms. Here we seek to provide objective guidance on thermal tool selection to practitioners who wish to adopt such tools to detect and monitor small endotherms. We compared the efficacy of three handheld thermal scanners (of varying resolutions) and a traditional spotlight for detecting small, cryptic endotherms at night. Random arrays of artificially heated small bird models (representing small, cryptic endotherms) were established along transects in native grasslands that support a range of small threatened endotherms, including the Critically Endangered Plains‐wanderer ( Pedionomus torquatus ). Transects were independently surveyed by five observers, blind to model locations and model density. Performance measures representing detection capability were assessed for all devices, and usability of each device was assessed with a survey completed by all observers. Detection rates, detection distances, and survey accuracy were greater for thermal scanners with resolutions of 320 × 240 and 640 × 480 than for the spotlight. A low‐resolution thermal scope (160 × 120) performed poorly for all performance measures. There was a consensus among users that a video camera‐style thermal scanner was most comfortable to hold and view while traversing the transect, as opposed to thermal scopes where users look directly through the lens. These results suggest that high‐resolution thermal scanners (≥320 × 240) provide improved detection capabilities compared to traditional spotlights. Higher detection rates provide opportunities for detecting and monitoring small endotherms at night where this was once difficult or impossible.
Publisher: BirdLife Australia, Ltd.
Date: 2022
DOI: 10.20938/AFO39160166
Abstract: Advances in technology are changing the way that ecological monitoring is carried out, especially for those species with ecological characteristics that have traditionally made monitoring difficult. Autonomous acoustic recorders coupled with automated signal detection software is one such approach where technological advances are delivering rapid improvements in the passive monitoring of vocal fauna. Here we characterise the three common call types of the endangered Mallee Emu-wren Stipiturus mallee and present a signal detection template, or call recogniser, for the species. We evaluate the performance of this tool against an independent dataset of field recordings containing Mallee Emu-wren vocalisations. The recogniser performed well with mean precision and recall metrics ranging between 0.55–0.97 and 0.70–0.95, respectively, depending on user parameters. This tool is widely applicable in the ongoing conservation of the Mallee Emu-wren, particularly as a low-cost method for post-release monitoring following a future Mallee Emu-wren translocation.
Publisher: BirdLife Australia, Ltd.
Date: 2019
DOI: 10.20938/AFO36163167
Publisher: Wiley
Date: 11-2021
DOI: 10.1111/CSP2.569
Abstract: Translocation, the human‐mediated movement of organisms from one area to another, is a popular tool in conservation management. Wild‐caught in iduals are more likely to persist following release than those sourced from captive breeding. However, this benefit of obtaining in iduals from wild populations must be carefully weighed against the potential harm to the viability of source populations. In this structured review, we assess the peer‐reviewed primary literature that addresses wild‐sourced translocation programs. We aim to determine what proportion of studies make a priori estimates of the impact of harvesting on source populations, what proportion provide quantitative evidence of demographic trends in source populations following harvest, and which methods are being used to assess impacts of harvesting on source populations. Of 292 articles reviewed, we identified just 32 instances (11%) where impact on the source population was estimated. The proportion of studies that assess impacts on source populations in a given year has not increased over time. However, studies that make explicit a priori comparisons of alternative harvesting strategies are becoming more frequent. We propose a standardized framework for reporting on management of translocation source populations. Published summaries of wild‐sourced translocations should include clear conservation goals, a description of the methods used to assess potential impact, an a priori justification based on evidence for the chosen harvesting strategy, an estimated timeline for recovery and a summary of postremoval population trends to assess the efficacy of a priori impact assessment. Routinely reporting impacts of harvesting on source populations will inform management when source sustainability is uncertain, improve transparency and increase the likelihood of successful conservation for many threatened species.
Publisher: CSIRO Publishing
Date: 16-04-2021
DOI: 10.1071/WR20133
Abstract: Abstract Context Species translocations are used in conservation globally. Although harvest for translocation may have negative impacts on source populations, translocation programs rarely explore ways of minimising those impacts. In fluctuating source populations, harvest timing may affect its impact because population size and trajectory vary among years. Aims We explored whether the timing and scale of harvest can be altered to reduce its impact on a fluctuating source population of Mallee Emu-wrens, Stipiturus mallee an endangered passerine in south-eastern Australia. Mallee Emu-wren populations fluctuate with ~5–10-year drought–rain cycles. Methods We used population viability analysis (PVA) to compare the impact of five harvest scales (no harvest, 100, 200, 300 or 500 in iduals) under three population trajectories (increasing, stable or decreasing) and two initial population sizes (our model-based estimate of the population size and the lower 95% confidence interval of that estimate). To generate a model-based estimate of the population size, we surveyed 540 sites (9 ha), stratified according to environmental variables known to affect Mallee Emu-wren occurrence. We used an information-theoretic approach with N-mixture models to estimate Mallee Emu-wren density, and extrapolated results over all potential habitat. Key Results We estimate that in spring 2019, the source population consisted of 6449 in iduals, with a minimum of 1923 in iduals (lower 95% confidence interval). Of 48 harvest scenarios, only seven showed no impact of harvest within 5 years (15%). Those seven all had increasing population trajectories and carrying capacity set to equal initial population size. Twenty-six populations showed no impact of harvest within 25 years (54%). These were either increasing populations that had reached carrying capacity or decreasing populations nearing extinction. Conclusions Initial population size, carrying capacity, harvest scale and population trajectory were all determinants of harvest impact. Given the importance of carrying capacity, further research is required to determine its role in the Mallee Emu-wren source population. Implications Harvesting Mallee Emu-wrens after high-rainfall years will have the least impact because source populations are likely to be large with increasing trajectories. For fluctuating source populations, flexibility in the timing of harvest can reduce its impact and should be considered during translocation planning.
Publisher: Resilience Alliance, Inc.
Date: 12-02-2019
DOI: 10.1111/JOFO.12285
Publisher: CSIRO Publishing
Date: 13-05-2021
DOI: 10.1071/PC20097
Abstract: When key ecological information is lacking, conservation translocations should be conducted within an adaptive, experimental framework to maximise knowledge gained and to increase the probability of success. Here we investigated whether timing of release or composition of release groups influenced indices of success during a trial reintroduction of the mallee emu-wren, Stipiturus mallee, to Ngarkat Conservation Park, South Australia. We translocated cohorts of 40 and 38 birds in the Austral autumn and spring of 2018 respectively. We released in iduals in small groups, comprising either familiar or unfamiliar birds, and intensively monitored all treatments for 2 weeks post-release to quantify short-term survival and dispersal. We used occupancy modelling to assess persistence of the translocated population for 2 years following releases. We also monitored source populations to assess the impact of removals. Mallee emu-wrens released in spring were more likely to remain at the release site and attempt breeding. Familiarity within a release group did not influence short-term survival. Mallee emu-wren occupancy at the release sites declined following releases and by July 2019 (12–15 months after release), we could no longer detect any emu-wrens. Density at source populations was lower 12 months after removal compared with pre-harvest levels, though these differences were not significant. Despite the failure to establish a population, we gained valuable management insights regarding both the focal species, and translocation practice more broadly. Timing of release can influence short-term indices of success. Spring releases should be considered priority actions in future mallee emu-wren translocations.
No related grants have been discovered for William Mitchell.