# 墾丁國家公園裡，寄居蟹快消失了

- URL: https://justfly.idv.tw/%e5%a2%be%e4%b8%81%e5%9c%8b%e5%ae%b6%e5%85%ac%e5%9c%92%e8%a3%a1%ef%bc%8c%e5%af%84%e5%b1%85%e8%9f%b9%e5%bf%ab%e6%b6%88%e5%a4%b1%e4%ba%86/
- 日期: 2026-09-23
- 分類: 我知故我在
- 標籤: 保育政策, 入侵種, 台灣生態, 國家公園

![墾丁國家公園裡，寄居蟹快消失了]
近百隻椰子蟹，只有一隻達到保護重量門檻。這是台灣生態學會2023年在恆春半島做的調查結果，數字擺在那裡，不用多加形容詞。椰子蟹是台灣最大型的陸寄居蟹，理論上受法規保護，實際上族群結構已經崩壞到近乎只剩幼體。

墾丁國家公園是全台知名度最高的自然保護區之一，每年遊客絡繹於途，海岸線、珊瑚礁、國家公園的招牌一應俱全。但招牌底下，海岸林裡曾經隨處可見、拖著貝殼緩慢爬行的陸寄居蟹，正在從這片核心保護區裡消失。台灣生態學會理事長劉烘昌指出，2024到2025年的調查顯示，大型陸寄居蟹已經幾乎從海岸林完全消失。這不是族群數量下滑，是幾乎看不到了。

##### 三個方向同時擠壓一種生物

先是外來種。黃瘋蟻（yellow crazy ants）是[入侵種](https://zh.wikipedia.org/wiki/入侵種)裡出了名的狠角色，在許多熱帶島嶼都留下生態浩劫的紀錄。牠們會集體獵殺陸蟹補充蛋白質，體型再大的寄居蟹也不是對手。這股壓力不是台灣獨有的問題，東南亞和太平洋島嶼同樣在應付黃瘋蟻的擴散，但恆春半島這次首當其衝。

再來是市場。大型陸寄居蟹市價高，商業捕捉的誘因跟著水漲船高。捕獲壓力持續上升，而長得夠大、夠值錢的個體，往往也是族群裡最關鍵的繁殖世代——牠們先被抓走，族群補不回來。

最後是法規。名義上椰子蟹和多種陸寄居蟹受保護，但保護措施在執行層面幾乎是空的。這種「有法律但沒保護」的狀況，其實在台灣其他保育領域也不陌生——海洋保護區同樣面臨人力不足、執法困難的老問題，墾丁國家公園海域面積約1.5萬公頃，海洋巡護員卻只有10名。陸域的陸蟹保育，處境並沒有比較好。

##### 曾經有效的做法，後來斷了

2000年代初期，台灣曾經推動過與貝殼供應相關的保育行動，一度看到成效——陸寄居蟹需要撿拾空螺殼當「房子」住，貝殼供應計畫等於是幫牠們補住房。但這個行動沒能持續下去，效果也跟著消退。保育不是做一次就結案的工程，停下來，問題就會捲土重來。

研究人員現在呼籲的方向很具體：加強執法、修訂法規。聽起來像老生常談，但對照近百隻椰子蟹只剩一隻合格的現實，這已經不是要不要做的問題，是還剩多少時間可以做。

##### 風景照裡看不到的東西

墾丁的觀光形象是陽光、沙灘、珊瑚礁潛點，陸寄居蟹從來不是主打的觀光賣點，卻是海岸林生態鏈裡清理有機質、幫忙鬆動土壤的角色。牠們安靜、不起眼、也不會出現在遊客的打卡照裡，正因為如此，牠們的消失才更容易被忽略——沒有人會為了「今年沒看到寄居蟹」而特地發一則貼文。

國家公園的名字本身帶著一種保證：這裡受到保護。恆春半島陸寄居蟹的處境提醒著，保護區這三個字，不會自動變成保護行動。

— 鄭佩玲

### Kenting Is Famous. Its Hermit Crabs Are Nearly Gone.

Out of nearly a hundred coconut crabs surveyed in 2023, only one met the weight threshold for legal protection. That single number, from a Taiwan Ecological Society survey on the Hengchun Peninsula, says more than any adjective could. The coconut crab is Taiwan’s largest land hermit crab, technically protected by law. In practice, its population structure has collapsed to something close to juveniles-only.

Kenting National Park is one of Taiwan’s best-known protected areas, drawing crowds year after year for its coastline and coral reefs. Underneath that reputation, something has been quietly disappearing. Land hermit crabs that once crawled across the coastal forest floor, shells on their backs, are vanishing from the park’s core zone. Liu Hung-chang, chairman of the Taiwan Ecological Society, points to surveys from 2024 and 2025 showing large land hermit crabs have nearly disappeared entirely from the coastal forest. Not declined. Nearly gone.

##### Three pressures, one species

First, an invasive species. [Yellow crazy ants](https://en.wikipedia.org/wiki/Yellow_crazy_ant) have a track record of ecological damage across tropical islands, and they hunt land crabs in groups for protein. Size offers little defense. This isn’t unique to Taiwan — Southeast Asia and Pacific islands face the same spread — but Hengchun is bearing the brunt of it now.

Second, the market. High prices for large land hermit crabs have driven up commercial harvesting pressure. The crabs most valuable to collectors tend to be the ones closest to breeding maturity — so they get taken before the population can replace itself.

Third, regulation. Coconut crabs and several hermit crab species are protected on paper. Enforcement on the ground tells a different story. It’s a familiar pattern in Taiwan’s conservation efforts more broadly — marine protected areas face the same staffing gaps, with Kenting’s roughly 15,000 hectares of marine zone patrolled by only 10 rangers. Land-based crab conservation hasn’t fared any better.

##### A fix that worked, then stopped

In the early 2000s, a conservation push tied to shell supply showed real results — land hermit crabs need empty snail shells to live in, and the program essentially restocked their housing. It didn’t continue, and the gains faded with it. Conservation isn’t a project finished once. Stop, and the problem comes back.

Researchers are now calling for stronger enforcement and revised regulations. It sounds routine, until measured against the reality of one crab out of a hundred meeting protection standards. This isn’t a question of whether to act anymore. It’s how much time is left.

##### What the postcards leave out

Kenting’s tourism image runs on sun, sand, and coral dive sites. Land hermit crabs were never the selling point, but they clean up organic matter and loosen soil in the coastal forest ecosystem. Quiet, unglamorous, absent from vacation photos — which is exactly why their disappearance goes unnoticed. Nobody posts about the crab they didn’t see this year.

A national park’s name carries an implicit promise: this place is protected. What’s happening to the Hengchun Peninsula’s land hermit crabs is a reminder that the words “protected area” don’t protect anything by themselves.

— 鄭佩玲