Dear MARMAM members, I am pleased to announce the open-access publication of our study "A stochastic model for estimating sustainable limits to wildlife mortality in a changing world" in Conservation Biology. In that study we are introducing a new modeling tool to determine sustainable limits to human-caused mortality of wildlife. We called this approach 'SAMSE' for ‘Sustainable Anthropogenic Mortality in Stochastic Environments' and applied this to a case study of bottlenose dolphins (Tursiops truncatus) that are impacted by fisheries bycatch in Western Australia. The main feature of this new method is that it allows us to incorporate stochastic, chance events. We found that current levels of bycatch in the region are unsustainable--especially when incorporating environmental and demographic stochasticity.
Oliver Manlik, Robert C. Lacy, William B. Sherwin, Hugh Finn, Neil R. Loneragan, Simon J. Allen (2022). A stochastic model for estimating sustainable limits to wildlife mortality in a changing world. Conservation Biology, e13897. https://doi.org/10.1111/cobi.13897 The article is available here, and the abstract is below: https://conbio.onlinelibrary.wiley.com/doi/10.1111/cobi.13897 Abstract: Human-caused mortality of wildlife is a pervasive threat to biodiversity. Assessing the population-level impact of fisheries bycatch and other human-caused mortality of wildlife has typically relied upon deterministic methods. However, population declines are often accelerated by stochastic factors that are not accounted for in such conventional methods. Building on the widely applied potential biological removal (PBR) equation, we devised a new population modeling approach for estimating sustainable limits to human-caused mortality and applied it in a case study of bottlenose dolphins affected by capture in an Australian demersal otter trawl fishery. Our approach, termed sustainable anthropogenic mortality in stochastic environments (SAMSE), incorporates environmental and demographic stochasticity, including the dependency of offspring on their mothers. The SAMSE limit is the maximum number of individuals that can be removed without causing negative stochastic population growth. We calculated a PBR of 16.2 dolphins per year based on the best abundance estimate available. In contrast, the SAMSE model indicated that only 2.3–8.0 dolphins could be removed annually without causing a population decline in a stochastic environment. These results suggest that reported bycatch rates are unsustainable in the long term, unless reproductive rates are consistently higher than average. The difference between the deterministic PBR calculation and the SAMSE limits showed that deterministic approaches may underestimate the true impact of human-caused mortality of wildlife. This highlights the importance of integrating stochasticity when evaluating the impact of bycatch or other human-caused mortality on wildlife, such as hunting, lethal control measures, and wind turbine collisions. Although population viability analysis (PVA) has been used to evaluate the impact of human-caused mortality, SAMSE represents a novel PVA framework that incorporates stochasticity for estimating acceptable levels of human-caused mortality. It offers a broadly applicable, stochastic addition to the demographic toolbox to evaluate the impact of human-caused mortality on wildlife. On behalf of my co-authors, Simon J. Allen, Bob R. Lacy, Bill Sherwin, Hugh Finn and Neil Loneragan. Greetings, Oliver Manlik Dr. Oliver Manlik Adjunct Lecturer Ecology and Evolution Research Centre Biological, Earth and Environmental Sciences (BEES) University of New South Wales Sydney, NSW 2052 Australia E-mail: o.man...@unsw.edu.au<mailto:o.man...@unsw.edu.au> www.bees.unsw.edu.au/oliver-manlik<http://www.bees.unsw.edu.au/oliver-manlik> ---------------------------------------------------------------------------------- <http://www.bees.unsw.edu.au/oliver-manlik> <http://www.bees.unsw.edu.au/oliver-manlik>Assistant Professor, Molecular Ecology Biology Department, College of Science, United Arab Emirate University, UAE E-mail: oliver.man...@uaeu.ac.ae<mailto:oliver.man...@uaeu.ac.ae> <http://www.bees.unsw.edu.au/oliver-manlik> --------------------------------------------------------------------------------------------------- Associate Editor, Ecology and Evolution Researchgate Profile<https://www.researchgate.net/profile/Oliver_Manlik> <https://www.researchgate.net/profile/Oliver_Manlik> Google Scholar<https://scholar.google.com.au/citations?user=gJ5oIEMAAAAJ&hl=en> Twitter: @OManlik<https://twitter.com/omanlik?lang=en>
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