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葛瑞 保羅 納博罕 1999/5/24
「牧場上的作家」廣播節目內容
當我們聽到墨西哥和美國西部邊境進行著檯面下的活動，直覺就會聯想到一些危害社會治安的不法情事：為飢貧所逼、政治所迫而流落他鄉的難民，或是毒販洗錢、走私毒品殘害我們的下一代。
但現在，一股另類的移民潮正在美、墨兩國邊界上演，且對雙方首當其衝的居民有利而無害。當您看到此篇報導時，成群的蜜蜂正跨越國境，循著牠們的甘露走廊採集花粉，走避墨西哥的熱浪來到美國西部山區。
天下至美我盡見，一切無有如蜂者
這群蜂擁而至的旅人，在檯面下默默地辛勤工作著，不為世人所知曉，也得不到眾人的肯定，只得承受自生自滅的危機。小型長鼻蝙蝠一般多為龍舌蘭授粉，但由於不當的礦坑挖掘或火藥爆破，致使整個春天聚集在岩洞中待產的上萬隻母蝙蝠死於一夕。在亞利桑那州，為樹狀仙人掌授粉的白翅鴿的數量，不到一世紀便銳減了一半，因為牠們用來築巢的河岸邊的樹木，都為人類的開發而倒下。褐背蜂鳥
(rufous hummingbird) 的數量也在近幾年內下降了百分之五，原因可能是因為牠們從墨西哥西部的阿利斯科州（Jalisco）到阿拉斯加的遷徙路線之間，中途停歇地的農耕型態改變，以致於「能源補給」植物越來越少。而美國大平原上噴灑的除草劑，大量毀滅了美洲帝王蝶 (monarch butterfly) 賴以維生的主要植物，其生存面臨前所未有的威脅。
只要這些採集花粉的蟲鳥數量持續降低，美國的自然環境就會逐漸失去它的的繽紛、芳香與豐富的物產。大自然造福人群的授粉生態，向來被我們視為理所當然，也就無人為之投注心力，但它可能很快就會讓美國消費者的飲食生活，增加上億的支出，為什麼？因為北美地區的本土蜜蜂，在我們活著的短短幾十年間不斷消失，且在我們有生之年，都不太可能再重回當初的數量。假如我們繼續蠶食這些授粉生物棲息的叢林野地，農民將必須引進他種半人工養殖的授粉生物，再將成本轉嫁到你我身上。
一百名墨西哥與美國的頂尖生物學家，最近來到亞利桑那州圖森市(或譯作土桑市)（Tucson），共同探討如何保護這些對人類貢獻非凡的授粉生物。他們的結論是，凡是屬於主要遷移路線上的中途站乃至於過冬的棲息地，都應確保多種開花植物的生長，加強管制國境兩側的農藥施用，並嚴密監控外來品種作物的栽種，以防破壞當地固有的生態。
授粉生物正處在滅絕的危機之中，因為牠們沒有所謂的生態真空期，人類也是一樣。然而諷刺的是，某些授粉生物延著墨西哥西岸遷移到美國西南部的路線，正好是西班牙裔移民的農耕區，他們冬季採收的作物，是我們民生所需的蔬菜。這些農民與鳥類、蝙蝠和蝴蝶同樣暴露在殺蟲劑和除草劑等化學藥劑之中，但體積較小的蟲鳥們往往死得較快。事實上，當區域生態發生異狀，足以影響到人類的健康之時，遷徙的野生生物常扮演著預警的角色。許多外地來的農民都飽受農藥的侵害，但最先遭殃的，總是野生生物。
下次當你再聽到或看到報導有關困難重重的渡境消息時，試想一下這種檯面下的授粉生物萬一不再過境時，會危及其他*哪些生物。墨西哥生態學家的努力，固然需要我們全力的支持，然而我們自己的家園──美國，也同樣迫切需要國人的支持。這些授粉生物在美墨兩國，都需要安全的生存空間。
 葛瑞
保羅
納博罕，受羅拉多州鮑尼亞市的高原新聞廣播電台之邀，為「牧場上的作家」之節目撰稿。他並任職於亞利桑那州圖森市的「亞利桑那╱索諾拉沙漠博物館」，為保存及科學部門主管。與人合著有《被遺忘的授粉生物（The Forgotten Pollinators）》一書。
本文為「牧場上的作家」廣播節目內容
原文與圖片詳見: http://www.earthday.net/grist/
mainevent/nabhan052499.stm
版權歸屬 Earth Day Network，環境信託基金會 (張正慈 譯，陳維立審校)
中英對照全文詳見：http://news.ngo.org.tw/issue/animal/
issue-animal00070501.htm
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by Gary Paul Nabhan, Writers on the Range 05.24.99
When most of us hear of undocumented border crossings between Mexico and the western United States, we immediately think of devastating social problems: refugees fleeing poverty and political oppression, or drug runners laundering money and offering controlled substances to our children.
And yet, there is another kind of traffic crossing the U.S.-Mexico border that is wholly beneficial to inhabitants on both sides of the geopolitical line. As you read this, migratory pollinators are crossing the international boundary, visiting wildflowers as they travel up their nectar corridor from tropical Mexico to the Intermountain West.
I think that I shall never see, a poem lovely as a bee.
These pilgrims are largely undocumented, under-appreciated, and therefore at risk. Lesser long-nosed bats normally pollinate century plants, but are threatened by the inappropriate gating of mines or by the dynamiting of cave roosts where tens of thousands of pregnant females aggregate each spring. The white-winged dove populations that pollinate saguaro cactus in Arizona have dropped 50 percent within our lifetimes, as their riparian tree roosts have died off or come under the plow. Rufous hummingbirds have suffered a 5 percent decline in population for several years running, perhaps due to vegetation change reducing "fuel availability" at their stopovers from Jalisco to Alaska. And monarch butterflies now face more herbicides killing their host plants in the Great Plains than ever before.
Should these pollen-carrying pilgrims continue to decline, the colors, fragrances, and productivity of American wildlands may be diminished as well. Pollination, one of nature's services that we've always assumed to be free and therefore unworthy of our investment and care, may soon cost American consumers several billion dollars a year in increased food prices. Why? There are now fewer domestic honeybees left in North America than at any other moment during our lifetimes, and they are not likely to recover in number before we die. If we continue to fragment wildland habitats where wild pollinators dwell, farmers will be forced to invest in husbanding other semi-managed pollinators, and will pass on their costs to you and me.
One hundred of the top biologists in Mexico and the U.S. recently convened in Tucson, Ariz., to figure out how to protect our valuable migrant pollinators. They concluded that we must protect the many flowering plants along nectar corridors, as well as the major roosts where pollinators stop over and winter. Pesticide use on both sides of the border must be more carefully managed and more diligently monitored, as must the spread of exotic species of plants that take over native habitat.
Pollinators are exposed to many risks because they do not occur in an ecological vacuum. Neither do humans. Ironically, some pollinators follow much the same routes up the west coast of Mexico into the southwestern U.S. that Spanish-speaking migrant farmworkers do while picking the winter vegetables upon which most of us depend. These farmworkers are exposed to many of the same insecticides and herbicides that birds, bats, and butterflies may succumb to because of their smaller body sizes. In effect, migratory wildlife may be the early-warning indicators that something is awry in the relation between regional environmental health and human health. Many migrant farmworkers' lives are being tragically impaired by toxins whose effects often show up first in wildlife.
The next time you hear or read of perilous border crossings, think of what other lives may be at risk if these undocumented pollinators ever stop coming across. Our wholehearted support for conservation efforts by Mexican ecologists is needed just as much as such support is needed here "at home." These pollinators need to be safe in both countries.
Gary Paul Nabhan is a contributor to Writers on the Range, a service of High Country News, based in Paonia, Colo. He is director of conservation and science at the Arizona-Sonora Desert Museum in Tucson, Ariz., and coauthor of The Forgotten Pollinators. |
