Diversity of land crabs in Hengchun Peninsula plummets, experts warn of ecological crisis

Hengchun Peninsula was once the paradise with the highest diversity of land crabs in the world. (Photo by reporter Cai Zongxian)

The Hengchun Peninsula was once a paradise for land crabs with the highest diversity in the world, but now it faces an unprecedented ecological crisis! Three conservation scholars, including Liu Hengchang, Li Zhengzhang and Qiu Yuwen, who have long been involved in land crab research, recently pointed out at a meeting advocating the protection of land crabs that in recent years, due to the infestation of exotic yellow crazy ants, man-made overfishing, and loopholes in regulations, the coastal forests of the Hengchun Peninsula have shown serious warning signs of "the disappearance of giant crabs and the death of coastal forests."

Liu Hengchang pointed out that during a survey of the Banana Bay Coastal Forest in 2002, land hermit crabs could be seen everywhere carrying plastic lids, plastic bottles and other garbage. At that time, the ecological community described it as: "Hermit crabs abroad are still living in the Stone Age, but hermit crabs in Taiwan are already desperate." We have entered the 'industrial age.

However, this evolutionary miracle has suffered a devastating blow in recent years; the latest survey from 2024 to 2025 found that "almost all large land hermit crabs have disappeared" in the coastal forests. The main reason is that "the bigger the crabs, the higher the price" in the market, which triggered large-scale commercial capture. The exotic "yellow crazy ants" also massacred land crabs and protozoa in order to supplement protein, causing the coastal forest to be almost silent at night. In a 2023 survey of conserved coconut crabs, only one out of nearly a hundred exceeded 1 kilogram, showing a serious breeding gap.

Li Zhengzhang pointed out that terrestrial hermit crabs can be called an "orphan group" in terms of evolution. Among the hundreds of species of Anomura, only the terrestrial hermit crabs (including the genus Coconut Crab and the genus Terrestrial Hermit crab) have truly completely landed. They rely on physical moisture retention in the microenvironment in their shells, which is an important key to their ability to survive on land. Therefore, habitat conservation is a top priority.

Regarding the common phenomenon of land hermit crabs being sold live in the market, Qiu Yuwen pointed out that the currently common land hermit crabs with wrinkles, concave feet, short arms, etc. are not listed as protected species (only coconut crabs are protected species). Stalls often claim that they "raised them themselves." However, hermit crabs cannot be artificially reproduced at present. Local governments and competent authorities should establish multi-level checks. The first-level inspection " The legality of the source of the Wildlife Conservation Law; the second level is based on the "Regulations on the Management of Profitable Wild Animal Breeding, Breeding, Trade, and Processing" to check the "breeding fishery registration certificate", "water rights registration", breeding records and invoice receipts. Without permission, it is illegal; the third and fourth levels should implement the spirit of the "Environmental Education Law" and animal welfare regulations to prevent illegal harvesting in the wild.

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In response to the public response to the "Sending snail shells to hermit crabs" campaign, by 2020, the population of land hermit crabs in Back Bay and other places had increased significantly to tens of thousands. (Photo provided by Qiu Yuwen)

Scholars believe that coastal forests have suffered a major decline in life. (Photo by reporter Cai Zongxian)

Experts call for a sound habitat and legal system to save land crabs. (Photo by reporter Cai Zongxian)