景观廊道有助于火蚁的蔓延, 但这种影响是短暂的, 博彩平台推荐的研究员朱利安Resasco说

随着栖息地的丧失和碎片化的继续, many in the scientific community view l和scape 走廊 as important for connecting habitat fragments to maintain biodiversity.

然而,, might those same l和scape 走廊 make it easier for invasive species to spread 和 cause greater harm to biodiversity?

这是个问题 朱利安Resasco他是科罗拉多大学的助理教授 生态与进化生物学系他已经调查了十多年. 他现在对一种特殊的入侵物种有了答案.

When Resasco first began researching the issue while working on his PhD, he found the perfect setting with the Savannah River Site Corridor Experiment in South Carolina, 哪个是世界上最大的走廊实验场地. 他还在 火红蚁通常被称为火蚁.

火蚁 are considered one of the most problematic invasive species in the United States, 对本地蚂蚁物种造成损害, Resasco笔记. 火蚁原产于南美洲, but have made themselves at home in the United States since the 1930s 和 today can be found in many southern states.

“The idea behind this experiment was to design an experiment to see how habitat fragmentation, 反之, 走廊, 影响生物的运动和生物多样性,雷萨斯科说. “And the Savannah River Site is an 80,这片占地1000公顷的土地归美国所有.S. 由能源部和林务局管理, so it’s one of the few places where large-scale experiments like this can happen.”

Resasco说 he initially contemplated focusing his research on small mammals, but eventually decided to study fire ants because they are so invasive. They worked well with the idea of potential negative effects related to 走廊, 它们在实验的规模上也很有效.

“此外，收集蚂蚁的数据也很容易，”他补充道. “所以，很快我就有了一个很酷的问题和大量的数据. 因为火蚁对共生蚂蚁非常有害, 我可以观察火蚁对走廊的反应, 和 what the effect is on the native ants that live with them.”

在某些情况下, 火蚁会袭击土蚁的巢穴, while in others they will simply monopolize the food 和 resources in areas they share with native ants 和 crowding them out, Resasco说, noting fire ants are more aggressive than their native counterparts.

创建大规模的测试区域

To test whether 走廊 aided the spread of fire ants, the U.S. 林务局创造了实验性景观，叫做街区. One block consists of a central patch created by clearing plantation forest, 为火蚁创造更好的栖息地, surrounded by three r和omly assigned patch types: connected 和 rectangular or winged. (Rectangular 和 winged patches were unconnected to the central patch.)

研究ers used pitfall traps to capture ant workers over a period of years, 包括2008年和2014年至2019年的每年, 估计火蚁和土蚁的密度.

Resasco说他在2014年发表的研究 生态 showed that fire ant biology played an important role in their degree of spread. 具体地说, trait differences between monogyne (single egg-laying queen) 和 polygyne (multiple egg-laying queen) colonies were important predictors of fire ant population densities, 它们对当地蚂蚁的影响和走廊的影响.

值得注意的是, monogyne queens taking part in large aerial mating flights will establish new colonies as far as several kilometers away from their natal homes, 而一夫多妻的蚁后则分散在较短的距离内.

“当一个群体只有一个蜂王时(一夫一妻制), 蚂蚁的行为是非常不同的,雷萨斯科解释道. “它们保卫大片领土，不让其他火蚁靠近, whereas in the polygyne social form there are many egg-laying queens per colony 和 they will not be aggressive toward non-nestmates. 而不是分散开来, they intermingle with each other 和 establish really high densities, 哪一个对本地蚂蚁的负面影响更大.”

由于它们各自的交配分散模式, Resasco说 his 2014 published research showed polygyne fire ants benefitted from l和 走廊, while monogyne fire ants—aided by their ability to fly above the tree canopy 和 for longer distances—were readily able to establish new colonies in patches regardless of whether they were connected with 走廊.

然而, Resasco说 he theorized in 2014 that the effects of 走廊 on polygne fire ants were transient, meaning fire ant density differences between connected 和 non-connected patches would dimmish over time, 当一夫多妻的火蚁完全在斑块中站稳脚跟时. 现在, 在过去的十年里进行了测试, 研究表明，情况确实如此, 说Resasco, 他最近出版了 最新研究结果 生态昆虫学.

“通常, invasive species are invasive because they’re really good at getting around, so 走廊 might not make a big difference one way or another if the species can readily colonize,他说. 同时, 火蚁只是入侵物种的一个例子, so there may be cases in which the benefits of l和 走廊 should be carefully weighed against drawbacks.

而元分析文章发表于 景观生态学最新报告 和 保护生物学 by Resasco 和 his colleagues found much evidence of positive effects of 走廊 和 limited evidence of negative effects, Resasco笔记 that “there could potentially be times when connecting 走廊 could have some negative effects we should consider,” adding negative effects of l和scape 走廊 are much less studied than positive effects. Study by other researchers on aspects l和scape 走廊 related to fauna, 昆虫和动物正在进行, 他补充说.

“The value of research sites like the Corridor Experiment at Savannah River Site is we can develop theories of how things work 和 test them out on larger-scale models,Resasco总结道. “这就是这项研究的价值所在.”

上图:一只火蚁女王(图片来源:Nash Turley)

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