Say you are on a road trip. You fall asleep, head lodged against the (hopefully passenger side) window. The last thing you see before drifting off is a string of stores: Starbucks, Target, Bed Bath and Beyond, Walmart, Home Depot……Zzzzzzzzz.
You wake up in half an hour, 2 hours, or 3 days, peek your eyes open and think you haven’t moved at all. The same string of stores would be outside your window again and again. Stop to eat in downtown Atlanta, San Antonio, Seattle or any city in between and you have the same experience. A few unique restaurants you never heard of and maybe you can track down some regional specialty but for the most part you have the same foods as in your home city.
This is called ‘urban homogenization’ and animals experience the same problem. Herbivorous insects and pollinators find the same plant species in urban landscapes across the country. Look outside your window. Do you see holly, boxwood, azalea, ligustrum, and cherry laurel shrubs? How about the trees?: red maple, lacebark elm, crape myrtle, crab apple? Since the plant community looks similar so does the community of arthropods that use those plants for food. Bugs that need a ‘regional specialty’ may be excluded from urban ecosystems.
The temperature, soil moisture, and air quality of distant cities are often more similar to each other than each city is to local natural areas. Kevin McCluney, a former postdoc in our lab (now at Bowling Green State University), conducted a study to determine if environmental homogenization among cities led to homogenization in arthropod hydration (or dehydration).
In a new paper, Kevin and coauthors report that due to homogenization in plant communities and landscape maintenance practices, like irrigation, that arthropods in a wet city (Orlando) and temperate city (Raleigh) were less hydrated than in adjacent natural areas but arthropods from a dry city (Phoenix) were more hydrated than arthropods from the adjacent desert areas. Thus, arthropods in very different background climates become more physiologically similar in cities.
Arthropod hydration and other physiological traits like heat tolerance affect their survival, plant and prey consumption, activity patterns, and reproduction. Understanding how physiological states change in cities can help predict the fate of species we are trying to conserve and the damage caused by pests to improve urban plant and wildlife management.
Read the full article:
McCluney,K.E., Burdine, J.D., Frank, S.D. (2017) Variation in arthropod hydration across US cities with distinct climate. Journal of Urban Ecology, 3 (1): jux003. doi: 10.1093/jue/jux003