Home on the Range Map

Abstract

Range maps fascinate entomologists, and we are not alone. Range maps show us which species live in a particular place, but they also show us how the world is changing, whether through climate change, the arrival of “invasive” species, or other aspects of the ongoing dynamic changes that constitute the ecology of our planet. I have a theory: most people are very aware of their own personal geographic setting, for political and economic reasons, so maps that show how other species overlap with our sociopolitical view of the world make a strong impression on us. In the course of working on my various field guides, I've given quite a bit of thought to range maps, and on more than one occasion, I have found myself caught up in controversy over the question of shaded versus dot maps. I preferred shaded, but I quickly learned that many of my colleagues feel that shaded maps are something less than truly scientific. They argue that a species isn't found everywhere within the shaded region, whereas dots represent actual instances, and preferably, actual specimens as well. My response has always been that a field guide is a summary, by an expert, of what species live where, how to identify them, and what they are doing, and a shaded distribution map is also a summary, based on expert judgment, of where a species might be found. I'll admit that I also prefer shaded maps because dots represent data points, and data is subject to ownership. A shaded map represents a notion of public domain knowledge, and sidesteps arguments about ownership of particular data points. …