Global wildlife trade threatens evolutionary history and ecosystems

• University of Sheffield scientists warn that the global wildlife trade has the potential to alter vital ecological processes in some of the world’s most biodiverse regions.
• Scientists find that areas of the tropics are hotspots for the diversity of birds and mammals in the global wildlife trade, which targets an evolutionary and functionally diverse range of species, with potential ramifications for essential ecosystem processes and the health of our planet.
• Researchers urge directing conservation resources and future research towards these trade hotspots to prevent substantial losses of species from ancient lineages and functionally distinct groups.

New research from the University of Sheffield has revealed that the wildlife trade relentlessly exploits numerous animal species, known for their uniqueness and ancient origins, across substantial regions of the world, despite their crucial contributions to the global ecosystems.

Global wildlife trade endangers biodiversity

Researchers from the School of Biosciences at the University have conducted a study revealing that the wildlife trade in many regions across the globe is endangering a diverse range of species with unique functions and evolutionary significance. This concerning discovery highlights the potential for significant losses in evolutionary history and disruption of crucial ecological processes.

The research, published in Nature, reveals that traders predominantly situate the hotspots of birds and mammals in tropical regions. These areas are incredibly rich in biodiversity, yet the trading of exceptional birds and mammals that play vital roles in the functioning of these ecosystems poses a risk of disrupting crucial ecological processes. This, in turn, can have adverse effects on both biodiversity and human communities that rely on these ecosystems.

The study's researchers are urging the allocation of conservation resources, including financial and political support, towards the tropics and other critical global wildlife trade hubs.

Trade endangers diverse species' functions

Professor David Edwards, the senior author of the study from the University of Sheffield's School of Biosciences, stated, "We need to urgently focus conservation resources towards trade hotspots, such as those in the tropics, to prevent extinctions, as thousands of species are globally traded, and many of these trade practices are unsustainable."

“At present, we’re in grave danger of losing some of the world’s most evolutionarily and functionally distinct animals, and this could have major consequences for our planet’s ecosystems".

The researchers synthesized previous studies on birds and mammals involved in trade, and combined them with global evolutionary and trait datasets. They used this information to construct a comprehensive mapping of diverse aspects found within trade. Functional diversity, which goes beyond species count and encompasses the range of traits and roles that species fulfill in ecosystems, was among the important aspects that were examined.

In addition, they examined phylogenetic diversity, which illustrates the evolutionary past found in a wildlife community. For instance, a community consisting of species from various groups or ancient lineages like pangolins and elephants would exhibit higher phylogenetic diversity compared to a community composed of closely related species. Both measures are crucial for assessing biodiversity and ecosystem well-being, as communities with greater functional and phylogenetic diversity tend to possess higher resilience against disturbances.

Trade risks altering ecosystem function

Liam Hughes, lead author of the study, says that by overlaying the range maps of birds and mammals in trade, researchers found that much of the world is using an overrepresentation of these metrics, particularly in tropical regions. The highest levels of traded phylogenetic diversity are found in areas of South-East Asia and sub-Saharan Africa, while parts of South America also emerge as epicentres of traded functional diversity. Hughes suggests that this high level of use implies that if trade in these areas is unsustainable, it risks substantially altering the evolutionary history present within these communities and the functioning of these ecosystems.

Despite considering the larger number of species involved in trade in the highly diverse tropical regions, the research reveals that a significant portion of the tropics serve as global hubs for the exchange of functional and phylogenetic diversity.

The study considers species abundance and identifies previously unrecognized areas in North America (where traders trade substantial evolutionary history despite relatively low species richness) and Europe (which witnesses trade involving a small number of species fulfilling diverse functional roles). These findings indicate that trade could potentially affect ecological processes in these regions as well.

The team also discovered that trade disproportionately represents larger species, suggesting that exploitation may specifically diminish the unique role they play in ecosystems. For example, the evolutionary distinct African Forest Elephant plays a vital role in ecosystems, creating openings in the Congo forests and dispersing the seeds of a wide range of tree species.

Trade threatens vital ecosystem functions

The rampant ivory poaching in recent years has caused a significant decline in various species, resulting in detrimental effects on forest health and carbon storage. Likewise, the trade of species like the Helmeted Hornbill, which plays a crucial role in dispersing large seeds over vast areas, has led to its Critically Endangered status due to the high demand for its sought-after casques, also known as 'red ivory'.

The authors emphasize the need for additional research to improve our limited knowledge about the sustainability of trade involving numerous species. They also urge for a greater emphasis on assessing the impact of species' roles in ecosystems within sustainability evaluations.

Liam Hughes (lead author) emphasizes that species with evolutionary distinctiveness play a crucial role in ecosystem functioning, making it imperative to protect these species and prevent unsustainable exploitation.

Dr Oscar Morton from the University of Sheffield’s School of Biosciences and a co-author of the study says, "When we remove or deplete certain species for trade, we risk changing the myriad of interconnected services that the ecosystem provides. Removing bricks from a building is similar to this - if we remove too many, we risk the whole building crumbling down. However, we currently understand frighteningly little of the scale of the issue or its wider implications for ecosystems."

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