It's 5000 BCE in the verdant swamps of North America, and this young deer has no idea it’s being hunted. Suddenly, an alligator hurtles out of the water at almost 50 kilometers an hour, locking its jaws around its prey and swinging wildly in a signature move known as the death roll. This deer never stood a chance, but then, nothing in this region can compete with this apex predator. These alligators easily devour the birds, turtles, and small fish living in what’s known today as Everglades National Park. But despite ruling the swamp for millennia, the last 500 years have brought deadly new predators that challenge the alligators’ reign. And the origins of these international invaders are just as unexpected as their impact on the Everglades.
公元前 5000 年,北美 地区郁郁葱葱的沼泽地上, 小鹿尚未意识到 自己已经成为猎杀对象。 突然,一只鳄鱼以接近 50 公里的时速窜出水面, 用嘴紧紧咬住猎物, 以标志性的动作猛烈旋转, 上演著名的“死亡翻滚”。 这只鹿根本没有逃脱机会。 然而,在这个地区,没有谁 能与这种顶级捕食者抗衡。 鳄鱼能轻而易举地捕食生活 于此的鸟类、龟类以及小型鱼类。 这里如今被命名为 “大沼泽国家公园”。 尽管鳄鱼称霸沼泽地已有数千年之久, 最近 500 年,却出现了 新的致命捕食者, 挑战鳄鱼的统治地位。 而这些外来入侵物种 的来历却出人意料, 正如它们自身给大沼泽地 带来的影响一样令人意外。
We tend to think of swamps as hostile landscapes since they’re overflowing with plant and animal life. But all this biodiversity makes these environments vital to regional food webs. And the Everglades are no exception. The park's subtropical climate can support species from around the world, and its borders are full of ecotones— transition areas between habitats— that connect the region’s freshwater prairies, rocky pinelands, mangrove forests, and more. Human activity has made the region even more biodiverse, developing Florida into a major port that welcomes countless human and non-human migrants.
我们往往会将沼泽想成凶险之地, 因为这里植物和动物泛滥。 然而,正是这种生物多样性使得环境 对区域食物网的稳定性 发挥着至关重要的作用。 大沼泽地的情况也不例外。 国家公园的亚热带气候能够维系 来自世界各地的物种生存。 公园边界遍布生态过渡带, 即各种生物栖息地之间的过渡区域, 这些生态过渡带将当地的淡水草原、 岩石松林地、红树林等连接起来。 人类活动使当地的生物多样性更加丰富, 佛罗里达也因此发展成为主要港口, 欣然接纳了无数人类 与非人类移民的到来。
In the 1500s, Spanish colonizers brought wild boar to the area, which quickly multiplied and uprooted the wetlands. They devoured alligator eggs and spread European parasites to local panthers. Then, in the 1800s, Florida’s shipping industry exploded, bringing all manner of new invasive species. Brazilian peppertrees blocked out the sun, water hyacinths clogged the rivers, and brown anole lizards upset the food chain. Alligator populations mostly endured this onslaught, but in the late 19th century, human intervention kicked things up a notch. Government and business officials wanted to turn the Everglades into farmland and began building canals to drain the swamp. They also planted non-native trees which crowded out the plants local birds relied on for food and shelter, which in turn limited the alligators’ supply of prey.
16 世纪,西班牙殖民者 将野猪带入当地。 野猪迅速繁殖,并摧毁了湿地。 它们吞食鳄鱼蛋,将源自 欧洲的寄生虫传播给黑豹。 然后,在 19 世纪, 佛罗里达的航运业蓬勃发展, 随之带来各种各样的新入侵物种。 巴西胡椒树遮挡了阳光, 水葫芦堵塞了河流, 棕色变色蜥蜴扰乱了食物链。 鳄鱼种群基本上顶住了这波攻势。 然而, 19 世纪末, 人为干预使事态升级。 政府和企业官员 想要将大沼泽地变成农田。 于是开凿水渠用以排干沼泽。 他们还引进外来树种,这挤占了 本土鸟类赖以食用 和栖息的植物生存空间, 进而限制了鳄鱼的猎物供应数量。
Interventions like this wreaked havoc on the Everglades for decades, until a conservationist named Marjory Stoneman Douglas finally came to their defense. In 1947, Douglas published a landmark book explaining that the Everglades were not only a unique and precious ecosystem, but that the region’s most fearsome residents were actually vital to sustaining it. During the wet season, alligators are constantly shaping the muddy landscape, drawing lines with their bodies and digging holes with their snouts, claws, and tails. In the dry season, these indentations become essential watering holes and firebreaks, maintaining and protecting the swamp’s other residents.
这样的干预行为在几十年间给 大沼泽地的生态环境造成严重破坏, 直到名为马乔里·斯通曼·道 格拉斯的生态环境保护者 终于站出来捍卫环境。 1947 年,道格拉斯出版了一本具有 里程碑意义的书,指出大沼泽地 是独特而宝贵的生态系统, 这里最恐怖的居民实际上 对于维持生态系统的平衡至关重要。 在雨季, 鳄鱼不断地打造淤泥景观。 用身体勾勒线条, 用大嘴巴、爪子、尾巴挖洞。 在旱季, 这些坑洼就成了必不 可少的饮水点和防火带, 维系并保障了沼泽地 其他居民的生存。
In the wake of Douglas’ book, Everglades National Park was established to formally begin protecting the landscape and its scaly stewards. But outside the park, conditions were brewing for the most dangerous invasion yet. Over the next 40 years, the exotic pet trade brought parakeets, iguanas, and relatives of piranhas to the region. In the 1990s, Burmese pythons became a cheap, popular pet for many Floridians. Some snake owners released their pets into the wild when they grew too large. But the python population really exploded in 1992 when a hurricane destroyed a breeding facility and released countless snakes into the wild. Since then, pythons have been connected to a 90% decrease in some local mammal populations, decimating the alligators’ food supply. And with help from other invasive reptiles like black and white tegus— giant lizards who devour alligator eggs— these snakes have made a serious play for the top of the local food chain.
道格拉斯的书出版之后, 大沼泽国家公园设立, 景观与鳞甲卫士的保护工程正式启动。 然而,在公园之外的地区, 迄今为止最危险的入侵 状况却正在酝酿发酵。 在接下来的 40 年里, 异域宠物贸易 将鹦鹉、鬣蜥和食人鱼 的近亲带入此地。 20 世纪 90 年代, 缅甸蟒蛇成为备受许多 佛罗里达人喜爱的廉价宠物。 当蟒蛇体型变得过大,有些 宠物主就将其放生至野外。 但 1992 年,蟒蛇数量 才真正呈现爆发式增长。 当时飓风摧毁了一处养殖场, 将无数蟒蛇放归野外。 从那时起,蟒蛇造成 某些本土哺乳动物数量锐减 90 %, 使鳄鱼的食物供应遭到严重破坏。 而且,在其他外来入侵爬行 动物的助力下,如黑白泰加巨蜥—— 一种会吞食鳄鱼蛋的巨型蜥蜴—— 这些蟒蛇已经开始争夺 本土食物链顶端的位置。
Today, Florida ranks among the regions with the most invasive species in the world. Some researchers suggest hunting these invaders down, while others recommend bringing in yet more creatures to balance the scales, such as releasing insects to eat invasive plants. It might seem absurd to try solving this problem with more foreign fauna. But perhaps a new arrival could fight invaders and feed the alligators— giving them the boost they need to reclaim their ancient home.
如今,佛罗里达被列为 世界上外来入侵物种最多的地区。 一些研究人员建议捉捕外来入侵生物, 但另一些人建议引入 更多的物种,以维持生态平衡。 比如释放昆虫,吃掉外来入侵植物。 尝试引入更多外来动物 以解决问题似乎很荒谬, 但也许引入新种群能够对抗 入侵者,还能养活鳄鱼—— 帮助鳄鱼夺回古老家园。