(waves splashing)
- [Narrator] When you think of islands,
you might think of pristine beaches and palm trees
gently swing along with a warm breeze.
Sounds like paradise.
And as a scientist,
islands are my kind of place for research.
Islands are very beautiful
and they also have a lot of biodiversity.
Biodiversity can be described
as the variety of species in an ecosystem.
Now, some ecosystems have higher biodiversity than others,
but all ecosystems have a variety
of species that interact in specific ways
with one another.
Islands have such a variety of species
that they're often called biodiversity hotspots.
They're home to so many diverse species,
much more so than the continents.
There are nearly half a million islands around the world,
but they only make up about 5% of the Earth's land area.
Yet, islands are home to 20% of the world's plant species
and 15% of all mammal, bird and amphibian species.
Many of these island species can only be found
on one island or within a group of islands.
For example, you can only find the 'i'iwi,
a honeycreeper bird species, in the main Hawaiian islands
in the North Pacific Ocean.
(birds chirping)
The 'i'iwi are important pollinator species
for Hawaiian plants, including the 'opelu
and and the 'ohi'a.
Pollination is an essential part of plant reproduction
allowing plants to produce their fruits and seeds.
While the 'i'iwi feeds on the sweet nectar of these plants,
this bird also helps to support the next generation
of 'opelu and 'ohi'a.
These and other types of interactions
are happening all the time
between species in an ecosystem.
You can think of biodiversity as a sort of safety net,
with each species as a knot,
and the ropes between knots as their interactions.
The diversity of species and their interactions,
hold the net together
allowing the ecosystem to function.
Plus, the relationships between species are often unique.
For example, the 'i'iwi has a special curved bill,
and it's evolved to feed on the nectar
of very specific flowers that are similarly curved.
Like the 'opelu.
Now, even though the 'i'iwi
is highly adapted to its environment, if something happens
to the 'opelu or 'ohi'a and the plants start to decline,
it can spell disaster for the 'i'iwi.
When an ecosystem changes so much
that a species can no longer survive?
That species may become extinct or die out,
causing biodiversity to decrease.
And unfortunately, many of Hawaii's honeycreepers
and overall biodiversity have been lost through extinction.
In the past, there were at least 20 other species
of honeycreeper found across Hawaii,
but many of them have become extinct over time.
If we return to our analogy of biodiversity
as a safety net?
Whenever a species goes extinct
it's like a knot becomes undone
and parts of the net start to fall apart.
A decrease in biodiversity
is often a result of human activities
which is especially clear in the Hawaiian Islands.
In the last few hundred years, agriculture, grazing,
logging and development have taken almost half
of Hawaii's forest cover.
And along with it, a big part of its biodiversity.
Humans have also brought non-native animals like rats
and feral pigs to Hawaii,
which have changed or destroyed native habitats.
Plus, new diseases and climate change
have led to the extinction of many Hawaiian species.
When an ecosystem loses biodiversity,
it doesn't function as well.
If 'ohi'a starts to disappear from Hawaiian forests?
It's not just the 'i'iwi
that loses an important food source,
but the entire ecosystem is affected.
In fact, scientists often look
at how complete an ecosystem's biodiversity is
in order to measure the ecosystem's health.
The safety net of biodiversity is supported
by having lots of different species,
which allows the ecosystem to cope
with natural disasters like drought, storms and disease.
With more biodiversity, ecosystems are stronger
and more resilient so they can recover quickly.
But, with less biodiversity,
ecosystems become more vulnerable.
I told you a lot about how Hawaii is losing biodiversity,
however, there is cause for some hope.
The nene, or Hawaiian goose, nearly went extinct.
There were less than 30 birds in the wild 50 years ago.
Now, thanks to lots of conservation work
to improve the habitat for those species,
there are over 3,000 nene throughout the islands.
We humans are part of earth's biodiversity too.
We are components of the ecosystems we touch.
So if we have the power to hurt these ecosystems,
we have the power to protect and heal them too.
Aloha.