Why is such a tunnel needed?

funny@lemmus.org to Ask Lemmy@lemmy.world – 703 points –

I found such a photo on the Internet and became interested in what function such a structure could perform.

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My guess is that it will be a “nature highway” so migratory species can cross over the road

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These are great for wildlife as they provide a safe crossing over high-speed highways. They are usually design to be in already existing migration paths where moving a proposed highway may not work and not disrupting migration paths is of importance.

So they're literally building the mountain next year. Neat.

They dug it out before. Later they rebuild it. But if they wait for a year, nature suffers much.

Looks like a nice choke point for a predator to hang about.

Possibly but I’d think it’s still safer than vehicles and less disruptive to overall migration for a given species.

I wonder if there’s been any studies showing how effective, if at all, these are.

There have been study's, these crossing are usually design to feel like open fields in a sense, so most animals will cross quick and on high alert to get through the "opening" in the field.

Are there any predators smart enough to strategize like this? I know that some use water holes as hunting grounds, but that's probably more instinctive than actual strategy.

Are there any predators smart enough to strategize like this?

it is the predators that build such passages. Have you ever seen any construction company building them? Even in the first photo that is under construction, there is not any human worker in sight

That under construction pit is the pit of the manlion. It's similar to the pit of the antlion, except for construction workers.

They always have to deal with the manlion before they start building. Often by pouring concrete over it.

So you're telling me lions and tigers built that tunnel and that natural bridge? okay.

Would they need to be that smart? Ambush predators that stay in roughly one area, for example, could naturally grow their numbers in the area around such a chokepoint simply by virtue of the ones in that area having more food available and therefore better survival chances.

I think that these human-made structures provide such a different environment (loud sounds from cars, moving/flashing lights etc.) that previous instinctual adaptations wouldn't trigger.

They can track other species by smell at least. If that path is used by too many and smells like a farm, they would probably get used to hang around it naturally.

Maybe canines? Idk

I just think it would be dope to drive under as a dramatic fight between an elk and wolves tumbled off the side onto my vehicle. Killing all of us instantly. What a way to go!

I know octopi have been escaping their aquarium enclosures and covering their tracks that humans would see. Just to take one at a time pray from their tank. If I recall correctly even killer wailes have been taking down human boats. In conclusion there are for Shure aquatic predators that use genuine strategy. Granted with my killer waile example is a similar case of is it strategy or instinct.

After seeing an aerial view of an African wild dog hunt, a coyote hanging out by a bottleneck doesn't seem outlandish. (here)

I don't imagine it would be a major problem though maybe it would let them get one or two easy meals but predators don't hunt unless they're hungry. So once they've taken down one prey animal they'll ignore the rest. On a species level it's probably not a major issue.

As opposed to roads which will kill lots of animals.

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It's taken into consideration of the design of these crossings.

I'd like to read about that,understand how it's done. it's a thought I have whenever I see them but of course the professionals designing them would have thought about it.

There was a documentary I watch years ago where they went into great detail into this, as well as the design of these things. Can't remember where i saw this documentary though.

Anyways, researchers setup cameras trigger by movement and body heat to watch these overpasses and found no evidence of higher predetor active.

They also went into detail about how these things are design with extra width and gentle slopes to make them as "friendly" as possible depending on the specific species that will be migrating in the area, as different wildlife species prefer different types of crossing structures.

For example:

Grizzly bears and wolves

Wary animals like grizzly bears and wolves there is a "learning curve", it may take up to five years before they feel secure using newly built crossings. Grizzly bears, elk, moose and deer prefer wildlife crossings that are high, wide and short in length, including overpasses

Cougars and black bears

Cougars and black bears prefer long, low and narrow crossings such as underpasses.

Elk

Elk are usually the first large species to use the new crossings, even using some while they are still under construction!

Here are some articles that talk about some of the studies:

https://wildlife.org/wild-cam-do-predators-ambush-at-underpasses/

https://www.nature.com/articles/s41598-020-67340-8

Yea elk don't give a fuck about much really. We have a few herds where I live and they don't even move when we walk our dogs nearby. I even have a video of one coming right up to the fence around my property, both my great pyrenees were losing their minds with the elk less than a foot away, the elk seemed more curious about the noisy little things ("little" relative to a full grown elk that is) than anything else.

It is like that playground game, but with less violence since only one player gets hurt at a time.

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It's also amazing visually! Forget regular highways! Let's have buried highways! That's especially good for if our country is invaded because we can install physical barriers to logistical supply lines against us!

Buried highways would be insanely expensive, and in the case of invasion, one well placed shot would completely kill logistics for the defenders as much as it would for the invaders, so probably not the best idea to rely on those

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Sure looks like an animal crossing.

Why do they put deer crossing signs on the highway? Why can’t they put them on smaller roads instead‽

Also, deer can't read street signs, so they don't know where to cross.

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It bothers me that someone actually said this,and was serious....

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This is the one! They're ridiculously effective, so much so that my home provinces is sinking like 250 million into building 5 more of them over the next 5 years

It actually takes 50 million to make these? Gimme 50 good men who want to be millionaires and we can figure out the capital cost between us.

A lot of the money is probably sunk into ecological surveys, permits, bureaucracy overall

Will there be compacted earth on top of the tunnel so animals can walk?

Yep, they call them land bridges. More of a hill than a mountain, but the meme is right!

This is cool. This is the first time I have heard about such projects.

So I was technically right in saying it would be an overpass, and as we all know technically right is the best kind of right lol

Nature is already a "nature highway", we fucked it up and now consultants sell the term "nature highway" to act like they are doing someone a favor. This is just restoring SOME man-made damage to an area to a less functional state than original for (hundreds of?) millions of dollars. Better than nothing sure, but not a "nature highway" for Simba, Timon and Pumba to dance and sing songs upon.

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That's an unfinished nature bridge.

Quite a common feature in Europe. Gives the animals safe passage over busy roads.

More or less safe. Predators often camp these choke points for obvious reasons.

I read pedesterians often camp these choke points. I was picturing hobo joe sitting there to catch a passing rabbit or deer for a good meal.

Fucking scrubs, can't hunt without getting an unfair advantage.

I've heard that makes the spot real popular with sparkly vampires.

not just that but it saves human lives as well by reducing animal collisions.

And the true motive bubbles to the surface. Drivers must be prioritized at all costs.

Edit: damn y'all really salty, ask yourself what the chances are they would have built this if only wildlife benefitted and maybe you'll see my point

You think people built entire highways just because they wanted the most inefficient and expensive way to screw over some deer? No fucking shit all this infrastructure is for driving.

No I thought they built highways because they wanted the most inefficient and expensive way to get around.

Common in New Jersey too. Were essentially Europe of America.

Well that explains the smell!

(I know very little about Europe or New Jersey)

"Essentially" is doing SOOOO much work there (for anyone not from America).

Hey, we're trying, just as hard as my "essentially" is.

I really hope you're making a joke cos of this one very limited example. Cos if not...

I mean, I thought it was obviously a joke, and you're there with me. Right? I took the use of land bridges, nature bridges, animal bridges, whatever term is used, and used it to compare the State of New Jersey to a continent, neither of which are homogenous enough to be able to even make a comparison.

I'm just curious why you really hope it's a joke though. I suppose I have the ire of some Europeans in drawing such a conclusion, and I'm genuinely curious why that's the case.

I guess the best place to start would be what's European?

The thing that made me question it is that Americans have a tendency of saying dumb stuff like you did, and mean it. Cos like you said, there is very little to properly compare them.

Were essentially Europe of America.

Get back to me when you have mandatory vacation time, universal healthcare, universal college-level education, universal pre-k, family leave, modern public transportation, non-crumbling infrastructure, climate-friendly policies, etc, etc.

NJ offers free community college, they're working on universal preschool but it varies district to district (my district is about to move it to thee years old), NJ Transit trains are built in Germany, so that's something right? We are working on offshore wind farms but the Dutch company backed out (and to be fair the economy is a shit show and I get it and I won't point fingers). NJ is pretty much as progressive as it gets in the US, which is why I referred to it, tongue in cheek, as the Europe of America.

Some of the US is trying, and the amount of unjustified shit reddit, and now Lemmy, throw indiscriminately at the US is foolish. To suggest Mississippi and Vermont are the same is just not true, but that's the vibe I get when I scroll through "America Bad" after "America Bad" post.

There's no reason for people to be up on their high horse when we're all a decade away from collapse. Let's be friends and joke with one another. Sometimes all you got is jokes.

Oh wow I didn't know new jersey had rail and walkable streets

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My first thought as well.

Also my first thought.

It was my first thought too

Actually it was my second.

Naaah, it was the first.

Honestly my first thought was snow shed but when I saw the nature bridge comments I was like oh derp yah that’s it. The slope isn’t steep enough to warrant a snow shed.

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They disrupt the nature a little less. Animals aren’t hit crossing the street because they can go over and other small benefits like that. They also look nice and tunnels are fun when your car sounds nice

It's not finished. It will look like this when they complete it. It's a nature bridge.

If a duct that transfers water is an Aquaduct, then a duct that transfers nature is an Ecoduct

In that case, the bridge in OP's image is currently just an airduct.

We had a few of these built in my country to allow wildlife to cross safely.

We’ve had a few of these built on my planet too actually

Coquihalla highway has something like this to keep avalanches and rocks off the road.

It's the only tunnel I've driven that has windows.

Great Bear Snow Shed https://maps.app.goo.gl/HJUSEtGB2Jg8FFTN7

Italy and austria have a lor of those because of the mountains.

This was my assumtion as well. Colorado (I.E. Red Mountain Pass) has such things for avalanches and rock slides.

Could be for a skii-slope as well. There are similar structures in Are, Sweden for example.

On ski mountains these are usually placed in an avalanche prone area to stop the snow blocking the road

They're probably going to build an overpass on top of it later

I think that the overpass needs more powerful supports

Curved Tunnel ceilings are quite strong, as they distribute the pressure of the surrounding rock/soil quite well. So if it is covered with loads of rocks and soil it could probably hold another street passing over.

I suppose it would depend on what is passing over.

I Are they are used to ski over the road, it enables the slope to go all the way to the city cente.

“I don’t understand a thing and therefore it’s dumb!!!”