McRae, L. | Search bioRxiv

bioRxiv2020

Body mass and latitude predict the presence of multiple stressors in global vertebrate populations

Multiple stressors are recognised as a key threat to biodiversity, but our understanding of what might predispose species to multiple stressors remains limited. Here we analyse a global dataset of over 7000 marine, freshwater, and terrestrial vertebrate populations, alongside species-specific trait data, to identify factors which influence the number of stressors a species is subjected to at the population level. We find that body mass and latitude can both influence the number of stressors a population is subjected to across ecosystems, with large-bodied species tending to be more threatened, except terrestrial amphibians which show the opposite trend. Latitudinal forecasts predict higher stressor numbers between 20{degrees}N and 40{degrees}N, and towards the poles. Global stressor distributions suggest a link between human population centres and stressor frequency generally impacting larger-bodied species. Latitude and body mass hence provide key predictive tools to identify which vertebrate populations are likely to be highly threatened, despite the strength of these trends differing between ecological system and taxonomic class.

ecology↗

bioRxiv2020

A global indicator of utilised wildlife populations: regional trends and the impact of management

The sustainable use of wildlife is a core aspiration of biodiversity conservation but is the subject of intense debate in the scientific literature as to how, and whether, species are best used and managed. While both positive and negative outcomes of sustainable use are known for specific taxa or local case studies, a global and regional picture of trends in wildlife populations in use is lacking. We use a global data set of over 11,000 time-series to derive indices of utilised and not utilised wildlife populations and assess global and regional changes, principally for mammals, birds and fishes. We also assess whether management makes a measurable difference to wildlife population trends, especially for the utilised species populations. Our results show that wildlife population trends globally are negative, but with utilised populations tending to decline more rapidly, especially in Africa and the Americas. Crucially, where utilised populations are managed, using a variety of mechanisms, there is a positive impact on the trend. It is therefore true that use of species can both be a driver of negative population trends, or a driver of species recovery, with numerous species and population specific case examples making up these broader trends. This work is relevant to the evidence base for the IPBES Sustainable Use Assessment, and to the development of indicators of sustainable use of species under the post-2020 Global Biodiversity Framework being developed under the Convention on Biological Diversity.

ecology↗