Transcriber: Ian Edwards Reviewer: David DeRuwe
In a time when successful conservation laws are under attack
and threatened to be rolled back,
we need to get creative about how we want to protect nature
and save species from extinction.
One approach is to look at the past
and see how relationships between species have changed over time.
Our planet has been through five mass extinctions,
during which 50% to 90% of all species on Earth were lost.
Imagine, suddenly, no badgers, no crickets, no emus!
In the 1980s,
scientists realized that we are losing species faster than usual
and predicted that we could lose half of all species by the end of this century.
Are we living in what is called the "Sixth Extinction"?
How do we know when an important species, a keystone species, is lost?
How do we know what a keystone species is?
There's still a lot we don’t know about the mechanisms of mass extinctions,
letting alone the biological life on this planet.
But we do know that diversity is declining.
We know that from fossil records, narratives of early explorers,
and believe it or not, chefs,
who are really good at record keeping,
letting us know what was served at palaces, in monasteries,
and on ocean crossing ships.
But how many of the species we know to exist right now
will leave fossilized remains for future scientists?
How many of them were recorded because of commercial, medical,
or culinary interests?
Throughout history, we only know about the loss of a species
if it was important to us, one way or another.
That is to say, if it was big or tasty.
But ...
(Laughter)
But what about the tiny, inedible creatures?
What has happened to them over the millennia?
Let’s look at the oceans,
home to over 200,000 named species.
Yet, scientists estimate
that only 30% of creatures out there have even been named and classified.
That means that 70% of life in the oceans
is “unknown” to science.
Just last year, researchers discovered several new species of invertebrates
in the deep Pacific Ocean,
which they named after Game of Thrones characters.
(Laughter)
In 2016, a new species of whale was discovered in the north Pacific ...
a whale!
How many more undiscovered species are out there,
what are their roles in the ecosystem,
and, how many have we lost before we could find them?
And in order to more efficiently protect our ecosystems,
we need to look at their inhabitants
and learn how they are connected to each other.
Nobody is an island,
and that is especially true for marine animals.
We can tackle that by looking at food webs.
Food webs are systems that connect small animals to big animals,
surface species to deep sea species,
land creatures to ocean creatures.
Everybody eats,
and most species eat in a specific way.
They occupy a trophic niche, a certain place in a food web.
Imagine walking down Commercial Street,
here in Provincetown,
looking for a place to get dinner.
You know what you want,
and several places offer just that,
but each restaurant has a different vibe to it.
You are an omnivore; you have several choices.
Your niche is big.
But then your friend speaks up and says,
“I’m vegan and gluten-free."
(Laughter)
And just like that,
your choices are limited to one or two places.
Your friend is a highly specialized consumer.
Her niche is very small.
Now, imagine instead of summer,
the height of our tourist season,
it’s January and only a handful of places are open.
What would you do?
Your friend would probably go hungry or have to cook at home,
but you could eat out.
As an omnivore, you have options.
And, this is how food webs work.
Specialists, like your vegan friend,
thrive when their food source is plentiful,
and then either move away or die when their food source is scarce.
(Laughter)
(Applause)
Omnivores usually do well, no matter what.
Now, it's fairly easy to trace food webs on land.
Scientists can observe their study subjects in the wild.
They can even provide them with different choices of food
and see what they pick.
When talking about marine food webs, things get a little more challenging.
So instead of direct observation,
we employ what is called “stable isotope analysis”
to trace food webs.
Now, let’s take the long way round to explain what that is.
As Carl Sagan so eloquently put it, “We are all made of star stuff."
And he was right.
Because nature is really, really good at recycling.
The star stuff he speaks of is made up of by atoms,
just like every single thing we encounter in our daily lives.
And those atoms, the ones that built you and me,
were formed in the Big Bang and are constantly being recycled.
Not only are we made of star stuff, we are also what we eat.
Chances are you're part dinosaur,
Cleopatra,
and the clam chowder you had last week.
(Laughter)
And we can trace that.
Almost all elements we know of: hydrogen, carbon, oxygen,
and the whole lot, have multiple forms ...
small variables like identical twins,
similar, but not exactly the same,
called stable isotopes.
We can trace food sources by analyzing stable isotopes in tissues
such as hair, scales, skins or bones.
Now don't worry.
I’m not going to get into any detail
about the fascinating and exhilarating world
that is stable isotope analysis.
(Laughter)
We have more pressing issues at hand,
like, how to use food web science to streamline conservation efforts.
Knowing what animals eat in the wild is important.
It tells us of their place in the ecosystem.
Knowing that, we can better predict their chances of survival.
Imagine the demise of our vegan friends
because of a sudden shortage of fruits and veggies.
(Laughter)
In my PhD research,
I focused on food webs in seagrass meadows.
Seagrasses, like the eelgrass here on Cape Cod,
are important ecosystems.
They provide hiding spots and cover for juvenile animals.
Small species can find shelter there, too.
Therefore, seagrass beds usually boast of a high species diversity.
Most of those species are invertebrates like crabs, worms, amphipods or clams.
In my research, I focus on invertebrates
because they are important food sources
for fish and larger animals that are commercially important to us.
What I found was a very big and intricate food web
in which almost every species was connected to every other species.
How? They eat each other.
It was complicated, and it still is.
So, I decided to find the common denominator
in this eelgrass bed,
the one thing that connects to everything else.
That species or group of species, in ecology,
is called the keystone species.
In architecture, the keystone is at the apex of an archway.
It's the one stone that, if taken away, would cause cathedrals to crumble.
Have you ever played Jenga?
It’s that last block that you had better left alone.
And I found it! .
In this eelgrass bed,
the keystone species was an amphipod, or side swimmer,
a small invertebrate, the size of long-grained rice.
Now, there may be three people in this auditorium
who have heard of amphipods before.
And they are probably people I work with.
(Laughter)
(Applause)
That is because amphipods are not something
we usually pay attention to.
They are small, smaller than half an inch.
They hide in aquatic vegetation or sediment,
and they are of no direct commercial interest at all.
But there are more than 9,900 species of amphipods.
They live in salt water. They live in fresh water.
They can even venture onto land.
They live in every ocean. They are everywhere.
Amphipods are important food sources for fish and larger animals
and keep algal growth and biofilms under control
by their grazing.
Models showed that if these creatures were absent,
fish might not find enough food and would move away;
algae would start growing uncontrolled, causing algae blooms.
This tiny little critter was, unknowingly, in control of its entire world.
(Laughter)
It was the make-or-break component of the food web I was looking at.
Now, I also learned
that every food web can have a different keystone species.
So, I set out to determine as many keystone species as I could,
and I’m still at it,
collecting animals, analyzing their stable isotope composition,
and figuring out how they are all connected.
Think social media.
You are connected to people you’ve never even met,
and I’m sure one of them is an over-sharer.
(Laughter)
Now, you might not know them,
but you would notice if they stopped posting,
(Laughter)
if they disappeared.
Now, I also learned that almost anything can act as a keystone species,
depending on the ecosystem you’re looking at.
What they usually have in common
is that they are small, inconspicuous, and not cute.
(Laughter)
That is why I have made it my mission to spread the word on keystone species,
on invertebrates, on amphipods,
on the creatures we share the ocean with
and depend on to provide us with healthy ecosystems.
We need them, but we don’t see them.
Now, it’s not always possible to “protect” a keystone species.
Look at this critter. It’s not even a quarter of an inch long.
There's no way you can protect that without accidentally stepping on it.
But here's what I think:
We most certainly can protect its habitat,
the area where it lives.
Does it need seagrass to survive?
Let’s protect and restore seagrass beds.
Does is need mangroves?
Let’s protect the mangroves.
Us humans, we usually tend to identify with our own kind,
with mammals.
Don’t get me wrong, my dog is the most adorable living thing.
Audience: Aww ...
(Applause)
And she deserves my complete attention.
But if we take, say, 5%
of the billions and billions of dollars that are invested
in the conservation effort directed at cute and majestic mammals
and focused it on not-so-cute and sometimes slimy invertebrates,
not only would we be able to save that one species,
but all the other species of clams, crabs, shrimps, snails, amphipods,
worms, urchins, sea cucumbers, fish, seagrass, mangroves,
and horseshoe crabs that are part of its food web and depend on it.
Not only would the invertebrates benefit,
the cute and majestic mammals,
and ultimately, humanity, would benefit, as well,
because we all depend on healthy ecosystems.
And to keep our ecosystems healthy
and help the ones that aren’t doing so well,
we need to start with the little things in a big way.
Imagine protecting and saving an entire ecosystem
by protecting a tiny little amphipod.
Thank you.
(Applause) (Cheering)