Study: Half the World's Species are on the Move
"We're talking about a redistribution of the entire planet's species," says Gretta Pecl, lead author of a new study in Science that examined the implications of wildlife on the move.
The changes already are quite dramatic. Malaria, for example, now appears higher up mountain slopes in Colombia and Ethiopia, as rising thermostats make way for mosquitoes at higher elevations. Leishmaniasis, a sometimes-fatal, once primarily tropical affliction, has moved into northern Texas as the sandflies that host the disease-causing parasite head north.
Agriculture is feeling the effects too, as crop pests expand their range. Diamondback moths, which ravage the cabbages, kale, and cauliflower grown by poor urban farmers, are spreading in South Africa. In Latin America, coffee plant funguses and pests are appearing in new areas, threatening a key industry. The same is happening to French olives, wine grapes, and lavender. And in the United States, scientists suspect climate change has promoted the increasingly rapid spread of Johnson grass, a highly invasive weed that reduces yields for legumes, corn, sorghum, and soybean.
Brad Smith