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Rebuilding A Forest? Just Add Termites - Video học tiếng Anh
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Rebuilding A Forest? Just Add Termites
Rebuilding A Forest? Just Add Termites
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Субтитры (116)
0:00
Termites eat wood.
0:01
That is their thing -- pretty much their entire deal.
0:04
So, if you were to guess which organism might be
0:06
counted on to restore a plot of destroyed rainforest,
0:09
termites might not be the first thing that comes up.
0:12
But what if an organism famous for destroying wood is actually
0:16
the thing that helps a baby rainforest grow big and strong?
0:19
It's a weird planet! And one group of Australian
0:21
researchers say these little wood-eating insects are probably
0:25
exactly what's needed to revitalize a wrecked rainforest.
0:31
[♪INTRO]
0:32
Rainforest restoration is more complex than you'd think,
0:36
partly because of a concept called succession.
0:38
The idea of ecological succession assumes that biological
0:42
communities replace each other over time, and that each stage
0:46
creates the conditions needed for the next community to thrive.
0:49
Conventional ecological wisdom says that the process of succession
0:53
eventually pauses once the community has reached a climax stage –
0:57
the forest's final form – where it remains until there is
1:00
a disturbance and the process of succession starts over.
1:03
So, even though it seems as if forest restoration would be as easy as
1:07
plunking down some baby trees and waiting a few years to enjoy a
1:10
little slice of "Fern Gully," the process is actually a bit more like baking.
1:15
Just like a cake isn't just a pile of flour, the successional stages of
1:19
an ecosystem need a bunch of ingredients to come together.
1:23
Ingredients like species, temperature, and time.
1:26
And termites have a place in the rainforest, too,
1:28
but one that we need to understand.
1:30
Your cake needs baking powder to rise,
1:33
but you definitely don't want it to taste like baking powder.
1:37
So, it's possible that the wrong amount of it could make
1:39
or break your cake. And the same might go for termites.
1:42
That is to say, termites could make
1:44
or break rainforest restoration, not a cake.
1:47
A cake, they would definitely ruin.
1:50
Anyway, an Australian research group began to think about the
1:54
part termites play in the succession of rainforest communities.
1:58
Decomposers like termites and mushrooms are vitally
2:01
important to the health of a mature rainforest
2:03
because they recycle carbon and unlock nutrients like nitrogen
2:07
from dead plants, allowing them to be used by new ones.
2:11
But generally speaking, a rainforest rehab starting
2:14
kit doesn't come with a little box of termites.
2:17
The researchers wondered if or when,
2:19
during the many-step succession process required
2:22
to transform a piece of cleared land into a mature rainforest,
2:26
termites would wander back in to do their job.
2:28
So, they monitored two different types of decomposers –
2:31
termites and mushrooms – in Australian replanted
2:34
forests in different successional stages.
2:37
Based on similar experiments in South America, they expected
2:40
the termites to waddle back in on their own, possibly even faster than
2:44
the mushrooms started breaking down old wood and leaf litter.
2:48
But it turns out Australia is built different, shocker.
2:52
The experiment involved placing blocks of wood in restored
2:55
rainforests of various ages, and they returned regularly for four years
3:00
to see how long it was taking the wood blocks to decay, and whether
3:04
the blocks had been discovered by mushrooms, termites or both.
3:07
The outcome was something of a surprise.
3:10
Turns out the Australian termites didn't spring into action
3:13
like the team thought they would, whereas the fungi got
3:16
right back to work, and returned to their
3:18
old growth forest decay rate very quickly.
3:21
And this is why you can go on Etsy
3:23
and find hundreds of mushroom-themed stickers,
3:26
t-shirts, and cross stitched pillows that say
3:28
You Cannot Kill Me in a Way That Matters.
3:30
With the termites, on the other hand, it actually seemed to take longer.
3:31
Although the experiment found that they eventually straggled back
3:33
into the reforested sites to munch on the wood blocks,
3:36
but they didn't show up in great numbers or very quickly.
3:39
Which isn't all that surprising, given that termite
3:42
colonies in Australia can take 25 years to mature.
3:45
The researchers suggested they would eventually build
3:48
a full head of steam in terms of population size and
3:51
biomass and get back to termite business as usual.
3:54
But what it means for rainforest restoration is that
3:57
Australian forest regeneration will probably have lower
4:01
rates of termite-driven decay than sites on other continents,
4:05
which may mean carbon and nutrients return to the soil more slowly.
4:09
The research team suggests that maybe we need to be thinking about
4:12
termite transplants from old-growth rainforests into younger forests.
4:17
Decomposers are necessary for nutrient cycling,
4:19
and the faster that gets going, the better!
4:21
Tropical rainforests are important because they house
4:24
around half of Earth's plant and animal species,
4:27
drive weather patterns all over the globe,
4:30
and act as the "lungs of the planet" by
4:32
making a bunch of oxygen and cleaning the air.
4:34
They also act as carbon sinks,
4:36
locking up huge amounts of atmospheric carbon dioxide.
4:40
In doing so, forests are essential for regulating the global climate.
4:43
Also, the plants in a forest hold onto a bunch of nitrogen
4:47
that needs to be unlocked by decomposers in order
4:50
for it to be used by the next generation of plants.
4:53
So, the part termites play in the life and growth of
4:56
a rainforest is very complex, and in order to restore these forests,
5:00
we need to understand a bit more about their place in them.
5:04
Unfortunately, we know so little about termites.
5:07
We know they produce methane,
5:08
a greenhouse gas we don't really want any more of,
5:12
but also they might be locking up giant
5:15
amounts of carbon in their nests.
5:17
So where they fall on the climate-friendliness spectrum,
5:20
we’re not totally sure.
5:21
Plus some species have a special relationship to nitrogen-fixing
5:25
bacteria, which provide the type of nitrogen plants need to grow.
5:29
They’re also very tasty to a lot of critters higher up the food web.
5:33
So, we really should get on understanding termites
5:35
a bit better because it's possible they would also lure other rainforest
5:39
species like lizards and sugar gliders back into the restoration site.
5:44
The point is, rainforest restoration is hard.
5:47
But at the end of the day, sometimes building a rainforest
5:50
requires adding in a little bit of something
5:52
that's going to tear the rainforest down.
6:01
[♪OUTRO]
