(gentle music)
- [Narrator] The science of measuring ecosystem diversity
is still pretty young,
but scientific knowledge at the ecosystem level
is now recognized as a critical part
of understanding total biodiversity on Earth.
Defining ecosystems is hard,
but we do know a distinct ecosystem when we see one.
We usually describe an ecosystem
in terms of a habitat and a climatic descriptor,
such as tropical rainforest or arid grassland,
but it's important to note that there's diversity
of habitats and ecological processes
within each ecosystem type.
You can have similar-looking ecosystems
that have very different makeups.
The name of an ecosystem doesn't automatically imply
that all the species in that ecosystem
are the same everywhere in the world.
High diversity among types of ecosystems means that there
will also be a high diversity of species themselves.
Each species is specialized to a type of ecosystem
in a particular place.
Most people are familiar with ecosystems
in terms of where they are,
that is, in terms of ecosystem distributions.
A tropical reef in the Philippines
will still be a coral reef
but, in terms of species composition,
could be very, very different from a reef in the Caribbean.
Organisms making up a Philippine reef might be similar to
and do the same jobs as those in a Caribbean reef,
but they will be different species,
sometimes very distantly related species at that.
In other words, the ecosystem functions performed
by these different reef organisms will be the same
in spite of how different the lists of species
from each reef might be.
And, in turn, the ecosystem functions will be similar,
but the species will be different
in the Great Barrier Reef off Australia
or reefs off Madagascar or wherever things
that we would label a tropical coral reef might occur.
To me, that's the essence of ecosystem diversity,
distinct types of ecosystems,
such as tropical reef or tropical rainforest,
combined with the diversity of the species
within a specific type of ecosystem.
Recognizing this means that we can ask
what makes a South American tropical rainforest
different from one in Africa?
It's always important to keep ecosystem diversity in mind
in any management or conservation strategy.
We can maximize protection of species numbers
in a given type of ecosystem
by protecting the most biodiverse example
of that ecosystem in the world.
For coral reefs,
that would be the ones in the Philippines, for example.
But what about all the others?
What effect will there be on the stability
of all Earth's ecosystems if we focus on
only one example of a particular ecosystem?
Is it enough to preserve a single ecosystem
as a kind of museum of diversity for that type of ecosystem?
I think most scientists would agree with me
that the only successful strategy is
to try to maximize the protection of as many ecosystems
and all their unique biodiversity as possible.
And there's another factor to consider
when we're talking about biodiversity
at the ecosystem level,
the interactions between the different types of ecosystems.
The interconnectedness of these systems is not best served
by labeling this or that ecosystem
as if it were some kind of distinct entity
that can be put in a giant, imaginary box and guarded.
There are complex webs of interactions among the species
that make each type of ecosystem unique.
But just as there are complex webs
of species interactions within ecosystems,
there are webs of interactions among ecosystems themselves.
And what will we lose
if we don't attempt to protect those interactions as well?