Minnesota's Natural Heritage (Second Edition)

Abstract

Gray wolves and moose are Minnesota’s iconic mammals. Both species reach their greatest abundance in the northern coniferous forest biome that occupies the northeastern third of the state adjacent to Lake Superior and the Boundary Waters Canoe Area Wilderness. In 2017, over 2800 gray wolves inhabited the state, and the population appeared to be spreading southward. In contrast, moose have been in decline. In 1994, 7000 to 8000 moose were estimated to live in northern Minnesota, but since the early 2000s numbers have been falling, and in 2018 there were fewer than 4000. Moose decline is attributable to a number of factors, including the effects of changing climate on forage. However, other factors are equally or more important. While gray wolves prey mainly on white-tailed deer, they also occasionally kill moose. In addition, logging in the northern coniferous forest created brushy, early successional woodland habitat perfect for deer, which now are far more abundant than they were before European settlement. With the large number of deer came ‘‘moose sickness’’ caused by a parasitic brainworm that is fatal for moose. Moose are also increasingly plagued by winter ticks (up to 40,000 per animal), probably as a result of more temperate winters. Heavily infested animals rub their hides on trees to relieve irritation and suffer exposure from hair loss; others can develop anemia. The plight of moose is illustrative of the changes wrought to Minnesota’s natural ecosystems by human dominance, which is thoroughly documented in this book. In the case of the tallgrass prairie in the southwestern and western parts of the state, conversion to agriculture is all but complete. Minnesota’s Natural Heritage could easily serve as a comprehensive and accessible ecology textbook with examples drawn from Minnesota’s biomes and ecosystems. Readers familiar with ecological principles will be rewarded with details of ecosystem processes in a Midwestern context. General natural history readers, especially those seeking specific information about Minnesota, should develop a deeper appreciation of ecosystem functioning when they have completed the book. This is the book’s second edition, originally published in 1995. The authors have significantly updated and revised the information to reflect changes in ecological thinking and modifications to the state’s landscape over the last quarter-century. Although not formally designated as such, the book functionally is divided into three sections, each with three chapters. The first three chapters serve as a general introduction. The book opens with a consideration of the state’s landscape, with an emphasis on underlying geology and the influence of the Pleistocene continental glaciers. The second chapter explores climate patterns and weather. The third chapter introduces general ecological principles that are important throughout the remainder of the book. Interestingly, the authors go to great lengths to review the evolution in thinking about ecological succession during the 20th century. They finally conclude that the concept of an enduring, changeless climax ecosystem as an inevitable successional endpoint is outdated. Nevertheless, the authors then go on to continue to use the term periodically throughout the remainder of the book where ‘‘late successional’’ sere would be more appropriate. The second section explores the state’s three terrestrial biomes: the deciduous forest, the northern coniferous forest, and the tallgrass prairie. The three biome chapters all follow the same format: beginning with a general overview, the authors then go on to describe the various vegetation communities comprising the biome. The community descriptions are followed by a consideration of some of the important and charismatic animals inhabiting the biome: mammals, birds, herpetofauna, and invertebrates. Following the faunal review, each chapter concludes with discussions of conservation issues, trends in