This episode is sponsored by Wren, a website with a monthly subscription
that helps fund projects to combat the climate crisis.
Click the link in the description to learn more about how you can make
a monthly contribution to support projects like rainforest protection programs.
[♪ INTRO]
Just about everything in nature goes back to the Earth after death.
Ideally, microbes and a few slightly larger creatures gobble up carrion
and leaf litter, thus recycling dead things and completing the circle of life.
Now, the climate crisis is making this
fundamental process run a little less smoothly.
Like everything in nature, it’s complicated.
But we’re starting to understand some of the effects on the humble arthropods
that break down leaf litter and other refuse.
And we’ll need to understand how those changes
will ripple through the ecosystem.
Unless you love the pool, hot summer days are unpleasant for just about everyone.
And while it’s far from the only effect of the climate crisis,
I don’t have to tell you that summer days are getting even hotter.
Warmer temperatures create favorable conditions for the bacteria that
play an important part in breaking down organic material.
So it’s tempting to think that hotter conditions mean
natural recycling processes work better.
But larger decomposers aren’t always so happy in warm temperatures,
though that does depend a lot on the specific kind of creature.
Either way, temperature can have a big impact on how fast things break down.
A lot of the critters responsible for decomposition are arthropods.
This is the phylum that includes insects,
arachnids like spiders and mites, and crustaceans.
But just like us, some of these animals just nope out at hotter temperatures.
Leaf litter from red maple and red oak trees, for example,
is supposed to get broken down by black field ants.
But just like you and me, the ants would rather sit in front of
an air conditioner than do backbreaking work while it’s hot outside.
The ants may be turning on their own, personal version of an air conditioner
by building and hiding in nests that are deeper and cooler
in response to higher temperatures.
And if this is the case, that means they’re not spending
as much time on the surface doing their leaf decomposition work.
Similarly, some of the woodlice that are supposed to break down
the leaves of the common lime tree are much less active during drought.
Researchers hypothesize that that’s because
if they spend too much time in the open, they’ll risk death by desiccation.
So instead of foraging, they spend their time
sheltering under the bark of dead trees.
This, too, slows down the decomposition process.
For other critters, though, the heat is much more welcome.
Hot temperatures favor many of the insects that break down carrion,
like decomposing beetles and flies.
Blowfly larvae, for example, develop faster when the temperatures are warmer.
The rate of development can be pretty stark, too, with larvae maturing more than
three times as fast in hot temperatures as in cooler temperatures.
When the larvae develop faster, they appear to do more nomming on carrion.
Insects may also use more energy in hot weather.
And animals that use up a lot of energy need more food
to support that faster metabolism.
When everyone is eating more, there’s less to go around.
So there’s sometimes also more competition in hotter temperatures.
Caddisflies, for example, are mothlike insects that live near freshwater.
Their larvae help break down leaf litter.
When it gets hot, caddisfly larvae compete amongst themselves for food,
and the winners tend to be the smaller individuals.
These smaller larvae are more efficient eaters and hence,
more efficient decomposers.
Predator activity can make a big difference, too.
Springtails, for example, are tiny arthropods that eat fungi and bacteria.
They are preyed on by mites, which get hungrier in hotter, dryer weather.
When mites eat more springtails, the springtails eat less fungi and bacteria.
That leaves more fungi and bacteria to do their job,
for example breaking down litter from maize as one study showed.
Ultimately, warmer temperatures do seem to have
an overall positive effect on decomposers.
But that doesn’t mean we can conclude that everything is fine, then.
Because the effect is species-specific,
we don’t really know how this will change the food web.
We do know that even small changes in the composition of species in a community
can have a profound impact on biodiversity.
So the effect might be a big problem in some habitats,
and much less of a problem in others.
But there could be other consequences, too.
It's possible that in places where decomposition slows down,
the leaf litter could accumulate just a little bit more, and we know that even
a little bit of excess fuel can contribute to catastrophic wildfires.
And when things don’t decompose, their nutrients don’t return to the soil,
and microbes, and the entire food web, lose out on an important energy source.
When you think about the impact of climate change on the circle of life,
you probably picture polar bears and Bengal tigers.
But the impacts can also be felt all the way down to some of the
smallest creatures, which do some of the most important jobs.
We’re still not exactly sure how changing temperatures and increasing drought
will impact our planet’s natural recycling process.
But it’s safe to say that keeping the world greener will make it
easier for those important critters to keep the world cleaner, too.
If these tiny critters can help, then so can we.
And if you want to do more, you might be interested in today’s sponsor, Wren.
If you’re looking to do something about the climate crisis,
this is one way that you can learn more about
your carbon contribution and take some action.
You can calculate your carbon footprint at their website,
and then see ways to help offset it.
This can be anything from fighting wildfires in California,
to helping indigenous people in the Amazon protect their home!
Once you signup to make a monthly contribution to offset your carbon footprint,
they’ll send you monthly updates so you can
follow your money and see how it’s helping.
We’ve partnered with Wren to plant 10 additional trees for the first 100 people
who sign up using our referral link!
Use the referral link in the description,
and thanks for supporting SciShow.
[♪ OUTRO]