A Field Guide to the Natural Communities of Michigan by Joshua G. Cohen et al. (review)

From the front cover, featuring volcanic cliffs in the northwestern corner of the state, to the last community type, sinkholes near Lake Huron, this book detailing key distinguishing features of Michigan’s natural communities is full of surprises. For a state that is commonly associated with either ‘Rust Belt’ cities or vast Great Lakes waters, this guide reveals the diversity and complexity that characterizes Michigan’s habitats. The authors of this beautiful book draw on their many years of work with the Michigan Natural Features Inventory (MNFI), and their field work and expertise shows through clearly.

The great strength of this book is its concise yet informative differentiation between numerous ecological community types that share many broader characteristics. The authors (and the MNFI) use a classification system that is common to a number of states, moving from the broadest category of class (e.g., palustrine, terrestrial, etc.) to subsetting groups (e.g., prairie, savanna, forest, etc.) and finally types (e.g., patterned fen, sandstone cobble shore, etc.) as the most detailed classification. Thus, the descriptions in this book can be directly compared with those in other states, especially those within the same bioregions. This taxonomy is especially clear in the palustrine community class, where no less than 33 types are distinguished from each other on the basis of landscape situation, soil characteristics, and especially, plant community assemblages! Careful examination of the expected species list for each of two similar communities (e.g., wet meadows and wet mesic prairies) quickly identifies the salient species to look out for when trying to categorize a particular site in the field.

As with any good field guide, this book features abundant high quality photographs; both of the community types as a whole, for a more gestalt-based analysis, and close-ups of characteristic plant species that would help users confirm their classification. Together with probabilistic maps of community distribution, and descriptions of typical landscape positioning for a given community, it becomes possible for readers to quickly narrow in on the desired community. An additional helpful feature is a short list of specific locations to visit that contain relatively-intact examples of each community type. The binding and pages are thick and durable, and should hold up to heavy use. Curiously, the authors omit captions for some of the photographs, even though many others are labeled. Perhaps intended to protect the locations of sensitive species, it nonetheless limits the field utility of some of the photographs.

Other features of the book are less successful in their goal of serving as a field guide to these communities. A major trouble spot lies with the dichotomous keys that are intended to guide readers quickly to the appropriate community descriptions. These are organized very confusingly, with no indentation or other visual clues to help orient readers to the next pair of clues. The number of items between alternatives also varies so much that it quickly becomes disorienting to use this key. This is especially frustrating given that a much more readable version of this key was printed in the earlier, more extensive report by these authors (Kost et al. 2007). That report also provided much more detail about each community, including notable animals, typical land use histories and land management considerations, all of which are absent from this book. In that sense, this book is more accurately a guide to the plant communities of Michigan, as those are the only taxa included. Another simple addition that would have greatly increased the usability of the book is an index by plant species. Since most occur in more than one community type, I wanted many times while reading to find other communities where a species was common, and couldn’t accomplish this quickly.

I suspect that many of these aspects of the book were an attempt to simplify the...