保全：監視されていなかったクモ類の国際取引の実態が明らかになった

Over 1,200 arachnid species have been or are currently traded around the world, almost 80% of which are unmonitored according to a study published this week in Communications Biology. The study highlights that millions of spiders, scorpions, and their relatives are bought and sold, and that there is a pressing need to monitor trade to prevent biodiversity losses.

Alice Hughes and colleagues investigated global arachnid trades between 2000 and 2021 by combining data from the US Law Enforcement Management Information System (LEMIS) and Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) international trade databases with a systematic search of global online arachnid retailers. This revealed that 1,264 arachnid species have been or are currently being traded, 993 (79%) of which are listed on arachnid-selling websites but not included in trade databases. This indicates that their trades are currently unmonitored and that these species may be vulnerable to unsustainable harvesting and trade. Among popular traded species, the researchers found during the study period that 77% of emperor scorpions were wild-caught, with one million individuals imported into the USA alone. Additionally, over 50% of tarantula species had been traded, including 600,000 Grammostola tarantulas, a group that includes the common pet species Chilean rose tarantulas. Two-thirds of individuals from all traded species were reportedly wild-caught, which the authors suggest could have negative impacts on wild populations if they are harvested to an unsustainable extent.

To identify potential barriers to monitoring the arachnid trade and its impacts, the researchers also investigated which species had been assessed by the International Union for Conservation of Nature (IUCN) and which were regulated by CITES. They found that out of over one million known invertebrate species, under 1% had been assessed by the IUCN and that the trade of only a small fraction of invertebrate species was regulated by CITES – for instance only 39 of the 52,060 known species of spiders. This indicates that the vulnerability of traded species is currently unclear and that trades are often unregulated.

The researchers suggest that a lack of data on most arachnid species ranges means that assessing vulnerability and developing appropriate management or conservation policies is currently almost impossible, whilst slow breeding rates and small ranges makes them particularly vulnerable. Improving the monitoring and regulation of this trade, in addition to improving understanding of the distributions and conservation statuses of wild arachnid species, will be essential to understand the impact of trade on natural populations and to prevent biodiversity loss, they add.