by Sophie Marsh
A new study presents an analysis of Red List data exploring levels of sustainable versus unsustainable use in wild species.
Scientists at University College London, ZSL (Zoological Society London), the IUCN (International Union for the Conservation of Nature) and others lay the groundwork for identifying the sustainability of use and trade across different taxonomic groups, and thousands of species. The study also investigates the main purposes of use of wild species, and the conservation actions - if any - that are in place to help prevent over-exploitation.
A year and a half ago, I undertook a research project aiming to use IUCN Red List data to investigate the patterns of human use across as many species as possible. This work was conducted with a team of experts from ZSL, IUCN, the University of Oxford’s Interdisciplinary Centre for Conservation Science, the International Institute for Environment and Development (IIED), the National Scientific and Technical Research Council (CONICET) of Argentina, and the UN Environment Programme World Conservation Monitoring Centre (UNEP-WCMC). One master's thesis, a manuscript, and many meetings and revisions later, our team produced a broad-scale analysis of Red List data, the first of its kind to span a range of 13 different taxonomic groups - a total of 30,923 species.
Why the Red List?
The IUCN Red List is a tool for estimating the extinction risk of species of animal, plants and fungi, but also provides a remarkable global dataset of information relevant to analyses of biological resource use. It documents the type(s) and severity of use a species may face (and hence whether it is contributing to increased extinction risk), the different purposes for which a species is used or traded, population trend data, and conservation actions that are in place or needed to address biological resource use as a threat.
The large number of published Red List assessments supports comparative analyses across a broad suite of species and taxa, allowing us to investigate global patterns in biological resource use. Our analyses required careful selection of data from standardized Red List classification schemes, and we only included species groups with sufficient data. The resulting dataset comprised six primarily aquatic groups: cephalopods, cartilaginous fishes, cone snails, bony fishes, reef-forming corals, and crustaceans; and seven mainly terrestrial groups: mammals, reptiles, dicotyledons, birds, conifers, cycads, and amphibians.
What are species mainly used for?
We found 10,098 species (around 40% of species we looked at) across 10 taxa with some form of harvest documented on the Red List. Corals, bony fishes, amphibians, reptiles, and birds are most used as pets or display animals. Crustacean species are mainly exploited
for human consumptive purposes, while cone snails (marine species with beautiful shells) are commonly collected as specimens. Cycads and dicotyledons are primarily used for horticultural purposes, such as cacti collected privately for their ornamental value, and conifers for building materials. While all utilized species have more than one use, we noted that plant species have more uses than animals.
Defining sustainable and unsustainable exploitation with Red List data
With species-level Red List assessments, we cannot systematically evaluate how specific instances of exploitation affect individuals: assessments focus on plants and animals in their entirety, generally overlooking localized uses and population fluctuations in favor of a comprehensive view of the species. We approached the question of sustainable use by focusing on the biological sustainability of the species. We defined “biologically sustainable use” as the use or trade of a species that does not contribute negatively to its extinction risk, nor cause a decline in overall population. In contrast, “biologically unsustainable use” is likely to increase the extinction risk of a species.
Can use of wild species be sustainable?
The use of wild species underpins the livelihoods of millions of people, but also presents a major threat to biodiversity. Can biological resource use sustainably help meet human needs and values, without driving species to extinction?
Our findings show that over-exploitation represents a major threat to many species, contributing to elevated extinction risk for at least a quarter of threatened and Near Threatened species. When looking at threatened and Near Threatened species, we found higher proportions of aquatic species for which use presents a threat: 100% of coral and 99% of cartilaginous fish species are impacted by use, which is their predominant threat.
Nevertheless, many Red List species are being used at levels that are unlikely to significantly increase their extinction risk. In fact, almost three quarters (72%) of Red List species which also had a documented use were categorized as Least Concern. Across all taxa, 34% of utilized species were Least Concern with stable or increasing population trends - this figure reaches 42% for birds and dicotyledon species. Finally, we found 172 threatened and Near Threatened species that were exploited (but not directly threatened by use) and not declining at the time of Red List assessment.
Are current actions sufficient to avert over-exploitation?
Previous research (e.g., Lichtenstein 2020; Austin & Corey 2012) has shown the use of wild species can be biologically sustainable with sufficient management. Policy and regulatory frameworks may promote sustainable use to ensure the long-term availability of natural resources. But these efforts must be informed by knowledge and research; our capacity to determine the effectiveness of conservation actions is limited by how well we can measure the impacts of use and the adequacy of management strategies. We investigated the prevalence of two conservation actions, international trade controls and species harvest management, in threatened and Near Threatened species for which use poses a significant threat.
We found over 206 threatened and Near Threatened species on the Red List that are not receiving either type of action to address the threat of intentional biological resource use. Out of 2,752 threatened and Near Threatened Red List species with intentional harvest listed as a threat, between 985 and 989 species do benefit from trade controls and/or harvest management. Used species are more likely to be covered by international trade controls (64% of species), such as those set up through the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), relative to species harvest management (9%).
Also, we found that of the harvested species with available Red List data, aquatic species are more likely to lack conservation management. Note that we chose to focus on intentional forms of harvest, where the use is intended for consumptive or trade purposes, as well as by-catch for cartilaginous fishes which are frequently traded even when caught unintentionally. This means there are likely many more threatened and Near Threatened species and forms of exploitation that are not being addressed by conservation actions.
With this study, we aimed to fill a gap in existing literature by assessing biological resource use across as many species as possible, spanning landscapes and aquascapes on a global scale. The report is meant to be as comprehensive as possible, and to support global policy instruments and capacity building for the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) and CITES. The Red List can play a crucial role in supporting assessment processes and is frequently considered in policymaking; ideally Red List data can be combined with other data sources to provide the most comprehensive analysis of the impacts of wild species use.
Click here to access the paper, and for a definitive assessment on the sustainable use of wild species, keep an eye on the forthcoming IPBES thematic assessment.
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