The Age of Nature

NARRATOR

Another indicator is the presence of very rare keystone species. BISON PUFFS BISON GROWL

FEMALE

This is the last place in Europe where European bison can be seen roaming free in the forests, in the fields. FLIES BUZZ And I think you can call it a success story. European bison disappeared from this area. The last one was shot about a hundred years ago, but people realised that this is a problem and they made efforts to reintroduce this species. So, now we have about seven hundred bison roaming the Bialowieza forest and I think they have quite a large role in the ecosystem. BISON GRUNT

NARRATOR

Bringing the bison back has helped make Bialowieza as natural as possible. They spread seeds over long distances and maintain open spaces... creating a variety of habitats for other species. This is how biodiversity works.

SPEAKER

So, the more complex a forest is, the more resilient against different changes it will be, against different environmental pressures which is really important now in relation to climate change because the more complexity there is, it's easier to adapt to new conditions. Because even if one species with some particular function in an ecosystem disappears because of climate change, there will be other species that take over this function. BIRDS SQUAWK

NARRATOR

This complexity gives the whole ecosystem a natural buffer, helping it to cope with any disruption. A forest like this is likely to stay healthier.

FEMALE

And a natural forest is not a stable forest. It's not that you always have, let's say 20 percent of spruce, 10 percent of pine and 30 percent of oak. It is changing with time, it's a very long process but it's changing. I think also that's why it's quite important to keep the forest like this, as a place of research where you actually can learn how things work and the different connections between species. And I would say that this is why biodiversity decline is such a worrying thing. Because it will have less biodiversity, the ecosystems will be simpler, they will not be that complex as they should be, to be able to withstand different pressures like climate change.