Wednesday, June 14, 2023

Map Critique: Wildlife Corridors of North America

 



The map above is a selection from National Geographic magazine’s September 2022 edition.  While I enjoy reading their maps, a close examination of this map reveals many problems and others the magazine has published.  Its title “Free to Roam” is strikingly lacking in clarity.  I would have kept this headline, but added some context to the map, such as “Free to Roam: Wildlife Corridors in North America”.  This is a title that not only grabs the reader’s attention but specifies what the map is about.  Perhaps the magazine was trying to avoid redundancy in the context of the article surrounding it, yet if we are seeing the map by itself, the only thing that helps to determine what it’s about is the scale at the bottom left, showing modeled flows of wildlife.

            Textually, the map can be difficult to read due to the choice of using a white font on a background that features very light colors where the corridors are.  I’d go with a different color scheme altogether, as there are many dark areas on the land that approach the same darkness as lakes, rivers, and oceans, which only works if the reader is someone who knows the geography of North America well.  I’d go with brown or green for land areas with no corridors, keeping it relatively dark; and changing from white to red where the corridors are.  Adjusting these colors would make the white font more legible.  Also, the captions have some interesting information, but they may be too small to read- a common issue in their magazines.  I would shorten them to become more succinct and make the font slightly larger.

            Sources for the data can be found in the bottom right corner of the map.  They are the Wilderness Society and USGS, which are reputable sources.  The problem is the map fails to report how the data was calculated by these organizations.  There isn’t even information in the article that points to their data collection methods.  The casual reader might see USGS in the sources and think it’s a legitimate map, but without any reference to the real data it is hard to take seriously as an academic source.  The cartographers could have been biased, making wildlife mobility seem like a bigger problem than it really is to raise more concern from their readers and keep them buying their magazines.  But I believe they used the right sources; they just weren’t transparent enough in how these models were calculated.

            Another problem with the data is that its one-dimensionality makes it subject to an ecological fallacy.  One might assume from the map that areas heavily populated by humans have less wildlife movement, which makes sense from the standpoint of urban areas impeding migrations.  However, if we look more carefully at the map, we can see that areas directly east of the Rockies are severely limited to migrating animals, conflicting with the assumption about urban density.  Adding more data to the map would help clarify this disparity: particularly population density and major transit routes.  Since population density east of the Rockies is low, it could mean that intercontinental transit routes are blocking animals from migrating.  Prolific farmland in the area could also be contributing to the problem.  Adding a layer of farmland might help show this relationship, but that could make the map appear messy with the other layers.  An insert or a separate map showing all the farmland on the Great Plains in comparison to wildlife corridors would be helpful in analyzing that.  Such a relationship would suggest that if corridors need to be engineered, they shouldn’t just consist of overpasses on freeways, highways and railroads, but pathways through farmland as well.

As stated above, I’d go with a different color scheme because the extreme brightness doesn’t contrast well with the extreme darkness.  To better differentiate land from water, I’d use green and blue respectively, then use a spectrum of red for the corridors.  Not only would this make everything more legible, but it would help readers locate areas.  Even the borders are white (I’d change them to black) on this map, making them blend in with some of the corridors.  Since the colors on this map are in shades of black and white, it actually works well for a color-blind audience, though a color printer might have difficulty printing every shade.

The cartographers seek to promote wildlife mobility awareness and do a fairly good job at it.  The bright colors and the headline grab our attention, just as the cavity in the middle of the continent raises our concern.  There is so much greater mobility in Canada and Mexico that it makes the reader wonder if U.S. policies are causing these disruptions.  Based on the map and its captions, the message is that as migration patterns are deteriorating, human engineered wildlife corridors are increasing.  The only counter is that it also states how the wall at the U.S.-Mexico border blocks mobility, which isn’t just a political statement; an endangered species can cross a freeway at the right moment, but a wall limits its movement entirely.  Complementary data could include conservation efforts that show how much a government works to conserve their environment compared to others.

 

Source:

Chwastyk, M., Schnure, M., NGM staff.  Free To Roam.  National Geographic Magazine.  September 2022 ed., 51.

No comments:

Post a Comment

Software

My body is the motherboard, With circuits that calculate The answer to every imbalance. My eyes are the monitor With rods and cones intercep...