動物可以作為消防員或無意的縱火犯影響火災(zāi)
動物可以作為消防員或無意的縱火犯影響火災(zāi)
Following the astonishing expansion of fires in the Amazon, Arctic, and Australia recently scientists are considering where animals fit in. Besides being victims to an utterly horrifying extent, animals can reduced the circumstances under which fires reach such terrifying intensity, but sometimes they can also create those very conditions.
最近，隨著亞馬遜、北極和澳大利亞的森林大火驚人地蔓延，科學(xué)家們開始考慮動物的生存環(huán)境。動物們除了成為可怕程度的受害者外，還能減少火災(zāi)達(dá)到如此可怕程度的情況，但有時它們也能創(chuàng)造出這種情況。
Many local councils use grazing animals such as goats to keep down grasses that turn to fuel in a dry spell. Dr Claire Foster of the Australian National University notes it's not just animals specifically employed for the task who fill this role. In Trends in Ecology and Evolution, Foster gives examples of creatures as diverse as termites and elephants that contribute to hazard reduction.
許多地方議會使用食草動物，如山羊，來抑制草的生長，草在干旱期會變成燃料。澳大利亞國立大學(xué)的克萊爾·福斯特博士指出，不僅僅是專門為這項任務(wù)而雇傭的動物才擔(dān)任這一角色。在《生態(tài)和進(jìn)化趨勢》一書中，福斯特列舉了各種有助于減少危害的生物，如白蟻和大象。
"One of the most amazing examples is from savanna ecosystems with termites," Foster in a statement. "They create massive structures where a huge variety of other animals choose to live. These 'nutrient islands' attract large herbivores that preferentially graze around the termite mounds, making them less likely to burn and creating a safety zone during moderate-severity bushfires."
福斯特在一份聲明中說:“最令人驚奇的例子之一就是熱帶草原生態(tài)系統(tǒng)中的白蟻。”“他們建造了巨大的建筑，其他種類的動物可以選擇在這里生活。這些“營養(yǎng)島”吸引了大型食草動物，它們喜歡在白蟻丘周圍覓食，這使它們不太可能被燒毀，并在中度程度的森林火災(zāi)中形成了一個安全區(qū)。”
Stephen Luntz
On the other hand, Foster notes, some animals have the opposite effect. “A lot of the things that make a plant good to eat are the things that make it hard to burn. When you take out all the nutritious, palatable plants, those left over tend to be drier and more flammable."
另一方面，福斯特指出，有些動物卻有相反的效果。“讓植物好吃的很多東西都是讓它難以燃燒的東西。當(dāng)你把所有營養(yǎng)豐富、美味可口的植物都拔掉后，剩下的那些就會變得更干燥、更易燃。”
Grassland habitats are safest when grazed by large beasts, but alpine areas are often the opposite, Foster reports. Foster explained to IFLScience that grazing animals usually suppress fires in high productivity environments, but in places with less productivity, which usually includes alpine regions, removing the grasses “can lead to shrub or forest encroachment,” making for greater fire danger. “[Flatlands] have lots of grazing-resistant grasses, so they tend to stay as grasslands,” she said.
福斯特報告說，大型動物吃草時，草原棲息地是最安全的，但高山地區(qū)往往相反。福斯特向IFLScience解釋說，放牧動物通常在生產(chǎn)力高的環(huán)境下抑制火災(zāi)，但在生產(chǎn)力較低的地方，通常包括高山地區(qū)，除去草地“可能導(dǎo)致灌木或森林的侵蝕”，從而導(dǎo)致更大的火災(zāi)危險。她說:“(平地)有很多抗放牧的草，所以它們往往是草地。”
"It's very clear that when used strategically, and in the right ecosystems, mammals like goats and cattle can have strong fire-suppressive effects, but I've also seen many examples where they actually do the opposite and increase the risk of severe fires," Foster said.
福斯特說:“很明顯，如果在適當(dāng)?shù)纳鷳B(tài)系統(tǒng)中合理使用，像山羊和牛這樣的哺乳動物可以起到很強的滅火作用，但我也看到過很多例子，它們實際上起到了相反的作用，增加了發(fā)生嚴(yán)重火災(zāi)的風(fēng)險。”
Foster also describes a few species with more distinctive consequences. Certain Australian birds have been observed deliberately spreading fires to flush out prey, while beavers maintain ponds and wetlands that act as firebreaks, protecting areas downwind. Animals trails can prevent the spread of low-intensity fires, and astonishingly this even includes ant trails, with areas around leafcutter ants' nests less likely to be burnt than other parts of the same ecosystem. Vizcacha, rabbit-like South American creatures collect wood for their courtship displays. The areas around occupied vizcacha burrows don't tend to burn because the inhabitants keep the grasses down, but once abandoned, these sites become particularly fire-prone.
福斯特還描述了一些后果更為獨特的物種。有人觀察到某些澳大利亞鳥類故意放火驅(qū)趕獵物，而海貍則在池塘和濕地上筑起防火屏障，保護(hù)順風(fēng)的區(qū)域。動物足跡可以防止低強度火災(zāi)的蔓延，令人驚訝的是，這甚至包括螞蟻足跡，與同一生態(tài)系統(tǒng)的其他部分相比，切葉蟻巢穴周圍的區(qū)域更不容易被燒毀。Vizcacha是南美洲的一種類似兔子的生物，它們會收集木頭來進(jìn)行求愛表演。被占領(lǐng)的vizcacha洞穴周圍的地區(qū)不容易被燒毀，因為居民們會把草壓下去，但是一旦被遺棄，這些地方就特別容易著火。
A lot more research is required to identify better ways to use animals for fire control, but Foster told IFLScience some lessons could be applied immediately. “In Australia we have a lot of ground-dwelling animals (including bandicoots, bettongs, and Malleefowl) that turn over leaf litter, mixing it with soil to make it less flammable. Many have been killed by cats and foxes and their reintroduction could bring big benefits,” she said.
需要更多的研究來找出更好的方法使用動物來控制火災(zāi)，但是福斯特告訴IFLScience一些經(jīng)驗教訓(xùn)可以立即應(yīng)用。“在澳大利亞，我們有很多生活在地面的動物(包括土匪、火鉗和槌頭貓頭鷹)，它們把落葉翻過來，與泥土混合，使其不那么易燃。許多人被貓和狐貍殺死，重新引入它們可能會帶來巨大的好處。”她說。
