埃里克·蒂特斯沃思（Eric Teitsworth）在寻找仅在北卡罗来纳州发现的巨型sal架时，沿着河岸沿着高大的草和灌木丛涉水。每隔几英尺，他就会拉到他放在水中的一连串陷阱中，看着里面。
He pulled up a few tiny fish, and a couple crayfish. But more often, he pulled up nothing.
Teitsworth，an NC State graduate student, wasn’t particularly surprised. This salamander, called theNeuse River Waterdog, is rare – it’s only found in rivers, streams and creeks in central and eastern North Carolina, and nowhere else in the world.
It’s also in decline. Teitsworth and克里希纳·帕西奇（Krishna Pacifici），北卡罗来纳州渔业，野生动植物和保护生物学计划的副教授证实，自1980年代以来，水狗已经急剧下降，这与结论得出了结论。北卡罗来纳州野生动物资源委员会biologists made several years ago. In July, the waterdog was listed as threatened by the U.S. Fish and Wildlife Service.
Teitsworth说：“我们认为该物种正在下降，我们不确定为什么，因此我们想在它完全眨眼之前先看看它。”
A giant among salamanders
Eventually, Teitsworth, Pacifici and Jeff Humphries, a wildlife diversity biologist from the Wildlife Resources Commission, got to the 24th trap. A cry of delight and surprise rang out.
Inside the trap was a light brown, spotted salamander with red-colored gills near its throat. It was a Neuse River waterdog, at last.
This was only the second waterdog Teitsworth has caught in a trap since March, although he’s been looking for it in rivers, streams and creeks from the Triangle all the way to New Bern. He’d been able to see a few others by snorkeling in the water, but he said it shows just how difficult it can be to find them. They are typically more active in cooler temperatures, he explained.
Teitsworth充满了一滴水，然后将水狗放在里面。他拍摄了它，测量了它，称重，标记了它并取了一个小组织样品。他说，它可能是5至10岁之间的女性，指出了其腹部的明显解剖结构。
While this salamander only measuring about six inches long, the species can be considered somewhat of a giant among salamanders. On average, the adults Teitsworth catches are closer to 7 to 7.5 inches, but the largest one he’s caught was a touch over 10 inches. They can live up to 20 years, and have unique spotting patterns on their back.
脖子周围的ill从透明的皮肤中获得红色，下面暴露了含氧血液。如果水中没有太多氧气，他们还可以通过皮肤“呼吸”。
它们在水生态系统中很重要 - 不仅是捕食者，而且作为其他动物的食物。
Their long lifespan is one of the challenges for researchers in fully understanding population changes, Pacifici said.
“他们是如此长，” Pacifici说。“这令人着迷，但它使得很难确定，他们的人口如何变化。”
深入研究
在1980年代，由阿尔文·布拉斯韦尔（Alvin Braswell）领导的罗利北卡罗莱纳州自然科学博物馆的研究人员开始进行调查，以估计水狗人口频率。北卡罗来纳州野生动植物资源委员会生物学家进行了2011 - 2015年的后续调查，发现它们从历史范围的35％消失了。
Teitsworth and Pacifici have built on the commission’s work to confirm the species has declined since the 1980s. They did not find the waterdog in about 60% of the 131 locations they looked for it.
现在，他们试图深入研究更深入的问题 - 不仅是那里还有多少水狗，还有什么原因导致它们消失。
Teitsworth和Pacifici由美国鱼类和野生动植物服务局资助，试图描述发现萨拉曼德人的栖息地，而他们没有发现，以了解导致其下降的因素。他们想充分了解水道周围的不同土地利用特征如何影响这些水道。
“I’m trying to understand the current distribution, and from that, what are some of the habitat characteristics that influence where it’s found, as well as some of the landscape characteristics,” Teitsworth said.
Already, they have some ideas about what’s going on.
“We’re starting to learn some of what we think is threatening them,” Teitsworth said. “It’s a cumulative effect of everything we’re doing on the landscape – landscape change is pervasive.”
累积效应
特别是，他们认为影响溪流，河流和小溪中水流的土地利用变化可以发挥作用。
Teitsworth说：“似乎分水岭的稳定性，尤其是在侵蚀和沉积周围，似乎是一个巨大的压力源。”“我们可能还可以弥补水质，甚至可能是入侵物种也是一个问题。”
他们解释说，开发可以通过增加不透水的表面来改变水狗栖息地，从而增加奔向河流或小溪的水的力和量。这可能会破坏水狗外观或食物，或者在水狗产卵的方式和地点。
“Typically in a healthy stream, you would have patches of rocky cobblestone, and faster and slower moving water,” Teitsworth said. “Increasing water flow into the river can change the natural habitat and homogenize it.”
They’re hoping to catch waterdogs in different life stages so they can understand whether, and where, they’re successfully reproducing. Their work could inform regulators’ efforts to develop a recovery plan for the species.
在支流中坚持
总的来说，蒂茨沃思（Teitsworth）在那天在那天在该地点检查的40个陷阱中发现了两个水狗，然后继续进行下一个陷阱。
约翰斯顿县的小河（Teitsworth）当天正在调查水狗的地方，是他定期返回的地点。
他认为，上游污染的影响可能在他是否会找到它们中起作用，而他在小河上的地点上游的区域更为乡村。在某些地点，他说他只俘虏了几个成年人。伊诺河就是其中之一。
“I have no idea if they are reproducing there,” he said.
Teitsworth补充说，例如，他不太可能在Neuse River的主茎中找到它们，但有时仍在支流中。
“Like this one,” he said.
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