Tuesday, October 29, 2013

Białowieża

0.4% of the world's European bison in one field.

This week, we are in Białowieża** National Park in Poland. Yesterday, we saw about 0.5% of the world's population.

**I've been pronouncing this name wrong for years. The ł is pronounced like a w, the w like a v and the ż like a zh. Bi-ah-wo-vay-zhuh. 

It's amazing the bison are not extinct.

Białowieża was the last wild refuge of the European bison. In 1914 there were over 700 here. In 1919, there were none. A hungry army extirpated it.

After WWI, the diaspora of bison gifted to zoos and kings, were brought together to repopulate Białoweiża.

Effective population size then: about 12.

Today, there are over 4000 European bison from that original group.

About a fourth of them are in Białowieża or the part of the old Białowieża that is now on the Belarussian side of the fence.

The animals are magnificent and so subtly different than North American Plains Bison. Stalking up to them through the forest was a rare treat...

The fundamental question about these animals these days is whether to think of them as forest animals that come out into open areas, or open area animals that take refuge in the forest.

As has been done for centuries in one way or another, hay is provided for the animals in pastures adjacent to the forest. They spend November – April eating here and then move back into the forest during the summer.

One important question is whether managers have set a trap for themselves. Hay is provided in the winter, which pulls animals out of the forest. This reduces pressure on the forest, which keeps the forest closed and filled with trees. The closed forest supports less bison, which necessitates more winter feeding.

It's a stable relationship, but the supplementing increases parasite transmission and messes with the animals' oestrus cycle, causing calves to be born too late (which necessitates further culling).

What scientists need to understand is whether a natural, non-supplemented system is possible. Can the forests be opened up, allowing bison to forage all year long in a more open forest system, eliminating the need for supplementation?

The system has been in place, no one knows if the alternative is possible.

There are stories of times when the forest was "overstocked" which opened up glades in the system. But was this overstocking? Or just a different system equilibrium?

Rafał Kowalczyk has done a great job finding out basic information about the bison, like what they eat. His graduate student Emilia Hofman-Kamińska is doing a great job looking at isotopes in bison skulls collected over the past 10K years to see if there were habitat shifts in the animals.

Still, large ideas like this need a lot more help. We need people to test alternative forest management practices. We need more measurements of diet. We need paleoecologists to reconstruct past animal numbers and diet.

The more we know about the ecology of the animals like this, the more secure is their future.

It seems like they (and us) deserve a secure future with more bison.


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