UNTIL the mid-19th century North America鈥檚 bison were among the most
numerous large mammals on Earth. Although the North American Indians hunted
them up hill and across plain, preferring them to deer, enough bison survived
to support them. As late as 1865 the explorer John McDougall described a plain
鈥減erhaps 10 miles across鈥� in which 鈥渋t did not seem possible to pack another
buffalo鈥�. Yet by 1875 they were devastated 鈥� shot out by 鈥渂uffalo skinners鈥�
and soldiers given carte blanche to take pot shots. The 鈥淚ndians鈥� had been
packed off to reservations.
But many Americans have long taken bison conservation seriously. Now 11 000
or so plains bison, Bison bison bison, and another 2900 or so 鈥渨ood bison鈥�, B.
b. athabascae, plus 4800 鈥渉ybrids鈥�, live in about 50 public reserves in North
America. Individual populations range in size from 15 to 4500. So the story
has a happy ending. Does it not?
Well, as Joel Berger and Carol Cunningham have shown in their five-year
study in Badlands National Park in South Dakota during the mid 1980s, long-
term management of 鈥渂ig animals in a small world鈥� is not exactly simple. Most
straightforward conceptually 鈥� but extremely ticklish nonetheless 鈥� are the
logistical problems. For example, bison wander outside the reserves 鈥� and they
carry brucellosis.
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More insidious, however, are the genetic problems. The park populations,
numerous though they may seem collectively, are isolated from each other.
Animals that evolved on continents where land is limitless are thus confined
to 鈥渋slands鈥�, where the ecological rules are quite different. Year by year
they lose genetic variation, and with it the potential for further evolution.
Theoretically the problem can be overcome by adopting the zoo practice of
ferrying breeding animals from park to park 鈥� but this is not so easy in the
鈥渨ild鈥�. Male bison imported to Badlands from Colorado proved too timid to win
mates, so their genes will die with them. The imported females are breeding 鈥�
impregnated by the Badlands鈥� males 鈥� but, oddly, their offspring seem less
viable than the 鈥減ure-bred鈥� Badlands animals. The attempted introduction of
new blood has had only limited success.
Then again, bison are not the only deserving species 鈥� and a reserve that
is good for them may not suit others. However, heavy grazing by bison created
excellent territory for prairie dogs which in turn might support reintroduced
black-footed ferrets. So this at least could turn out well.
Conservation needs this kind of intensive research, although the five-year
Badlands study cost $400 000. This book is a fine description of it. I
would like to see a popular version, however, for everyone from greens to
politicians must begin to appreciate the real difficulties.