Urban specialization reduces habitat connectivity by a highly mobile wading bird

Movement Ecology

Photo courtesy of Claire Teitelbaum

Corresponding Author: Claire Teitelbaum, cteitelbaum@uga.edu

Summary by Ethan Hackmeyer

Urbanization can cause substantial changes in the movement behavior of animals. However, researchers do not completely understand the downstream effects of urban-induced alteration in behavior. Mobile animals can deposit important nutrients and seeds as they move across the landscape, making the effects of urbanization on movement patterns increasingly important to understand as the percentage of land taken up by cities continues to increase. A new study led by CEID member Claire Teitelbaum explores how urbanization changes movement patterns of American white ibis in South Florida, and discusses the potential impacts these changes could have on Floridian ecosystems.

To track the movement of ibis, both in urban and natural areas, researchers placed GPS tracking devices on ibis and monitored patterns during their non-mating seasons from 2015 to 2018. Every two hours, GPS coordinates were logged in order to get an accurate measurement of both daily and long-term movement. Mating season data was discarded because ibis usually migrate out of South Florida in order to breed. From this data, researchers constructed a habitat connectivity network, showing how much the ibis moved and what locations they used. This was then compared to a simulated network that was constructed with built-in assumptions that the ibis would not prefer any specific habitat.

When compared, the GPS data network showed less movement of individual ibis than the simulated network predicted, indicating that urban environments likely impact movement patterns. Urban ibis were observed to stay in urban areas, and the ibis from the natural wetlands tended to avoid more developed areas. ibis in urban areas showed less movement overall, possibly because they were being fed from human sources, while “natural” ibis moved about as much as expected, but avoided cities. These findings suggest that  urban areas reduce population connectivity, with ibis having fewer interactions with ibis from areas with different levels of development. As a result, nutrient transport, gene flow, and disease dynamics are also likely altered by increased urbanization, warranting further study. However, it was found that a small percentage of the ibis did move between area types, acting as a connection between urban and natural populations.

Teitelbaum et al. (2020). Urban specialization reduces habitat connectivity by a highly mobile wading bird. Movement Ecology 8:49 https://doi.org/10.1186/s40462-020-00233-7