在采煤时代, workers would take canaries down to the tunnels with them to detect carbon monoxide. Canaries would warn miners of the impending danger in their surroundings.
Some environmentalists say Northern spotted owls in the forests of the Pacific Northwest are like the canaries in the coal mines. As an 森林健康指标, the spotted owl population also serves as a warning signal for the condition of its environment.
但也有坏消息.
“(斑点猫头鹰)正处于功能性灭绝的轨道上, 可能在本世纪内,” says Dan Donato, 一个科学家 华盛顿自然资源部.
那么这对斑点猫头鹰经常出没的森林意味着什么呢?
一个金发姑娘的栖息地困境
According to Donato, if you define forest health by a landscape’s ability to sustain populations of all its native species, then the decline of the spotted owl shows the forests it inhabits may be in trouble.
Donato specializes in the research and monitoring of northern spotted owl habitats, 它们依赖原始森林生存. The U.S. 农业部有 不同的定义 是什么构成了原始森林, 但他们通常都包括老年人, 成熟乔木,澳门威尼斯人游戏干直径大,澳门威尼斯人游戏冠层密.
This specific type of forest is becoming increasingly rare after decades of harvesting, disease, 还有昆虫侵扰. The 植澳门威尼斯人游戏节基金会 partnered with the 华盛顿自然资源部 to plant a dense tree canopy over thousands of acres to help spotted owls survive. 道格拉斯冷杉的种植, Western hemlock and Western redcedar mimic a similar structure of old-growth forests and serve to help owls nest, roost, and forage.
The destruction of old-growth forests caught the attention of the White House in 2022. 拜登政府发布了 an executive order that requires the U.S. Departments of Agriculture and the Interior to develop policies to address threats to old-growth forests.
A majority of the Northern spotted owl’s range is in old-growth forests on the coastal side of the Cascade Mountain Range. Unfortunately, 在这个湿润的地区, old-growth has been logged and the forests have been converted to new growth. Donato says this conversion of the land and habitat fragmentation has had a drastic impact on the species and are the most critical threats to the owl’s survival.
虽然猫头鹰大多生活在山区湿润的一侧, there are also some dry forests within their range standing east of the Cascade Mountain Range crest. 但是缺乏水分, 加上典型的老生长特征, 使得保护森林变得困难.
“斑点猫头鹰栖息地的许多结构特征, 就像密集的多层澳门威尼斯人游戏冠, 这些都是你所说的燃料堆积吗,” Donato warns, 指的是野火用来摧毁森林的植物材料.
为了防止野火——这是美国西部的一个可怕问题 浓密的澳门威尼斯人游戏木需要修剪 作为燃料管理的一部分.
“但如果你把它削得太薄,把它打开,这样它就防火了, 你让这里不再是斑点猫头鹰的栖息地了,” Donato cautions. “就是这种持续的紧张, and it’s actually one of the big active areas of both research and management: ‘How do we provide both?’”
Still, Donato notes that shrinking habitat is not the sole issue facing the northern spotted owl. 还有一个不同的对手:
THE BARRED OWL
最重要的是失去了它最喜欢的栖息地, 斑点猫头鹰面临着另一个挑战:一只更大的, aggressive cousin. The barred owl is native to Eastern North America but has now set up camp in the spotted owl’s West Coast territory. 科学家们也不确定原因.
“据大家所知,它不是被带到这里来的. 它只是移民到整个大陆,”多纳托说.
不管横斑猫头鹰为什么来到这个地区, the changing landscape of the American West is making it easy for them to stick around. 而斑点猫头鹰需要原始森林才能生存, 横斑猫头鹰在年轻森林和老森林都能茁壮成长. 这意味着现在的环境对横条纹猫头鹰有利.