Synopsis "The Wind Cave Bison Herd: A Century of Success (in English)"
The American plains bison, also known as buffalo, is an iconic and keystone Great Plains species. However, they almost disappeared from the face of the earth at the end of the 19th Century. Shortly thereafter, 20 bison were reintroduced to Wind Cave National Park in western South Dakota. A century later the herd not only survives, it prospers. Over 2,500 surplus bison have been shipped to other entities to start or augment other herds; had those bison and their offspring been allowed to procreate to their full potential they would have produced a staggering 140 million animals by the year 2020. This success occurred at the same time the park killed over 1,000 bison in a successful effort to eradicate brucellosis. But Wind Cave's contribution to the global recovery of bison is only part of the story. The bison reintroduction has been a 100-year experiment, and the park is the laboratory. In addition to describing the fascinating recovery of bison, the book reports the lessons to be learned from a hundred years of conserving a large animal on a relatively small tract of land. For example, throughout the herd's history, there have been concerns of inbreeding, with many calls for introducing "new blood" into the herd. Yet a century later the descendants of those animals not only survive, they prosper. Yet the weights of the animals appear to be decreasing over at least the past 50 years. A plausible explanation is climate change, yet the data suggest that time itself may be a bigger factor than weather. Are the animals getting smaller in part because they no longer face predators or harsh winters? Are the more successful females those that mature earlier and invest more energy into reproduction versus survival? Could the decrease in body size be a form of insular dwarfism? Although there is a long-term decline in body size, there are short-term variations due to rainfall amounts. Although the herd is very lightly stock, increasing rainfall results in increasing weights. But what is surprising is that the current year's rain has less correlation than rainfall several years prior. A plausible explanation is that rain 4-7 years back improves the range for the next few years, which improves the condition of cows, which in turn increases calf sizes, which results in heavier yearlings several years after the wet period. Such long-term patterns can only be established with long-term data sets. In that regard, the Wind Cave Bison Herd is a priceless resource and the story needs to be told.
