Hotter climate makes city life tougher on native wildlife
(CN) — A warming climate can exacerbate barriers native mammals face trying to survive in the growing urbanization of cities, according to a paper published Monday in Nature Ecology & Evolution.
In partnership with the Urban Wildlife Information Network, researchers and scholars studied data from 725 sites outfitted with cameras located across 20 cities in the United States and Canada to evaluate the effects of ecoregional characteristics and mammal species traits on the urbanization-diversity relationship.
The data were collected using a camera-trapping protocol established by UWIN for the long-term monitoring of ground-dwelling wildlife species. The passive, infrared-triggered cameras were located along wildlife travel corridors such as parks, preserves, riparian corridors and trails. The cameras captured 37 native mammal species from the images, including black bears, chipmunks, cougars and white-tailed deer.
“Species occupancy and diversity were most negatively related to urbanization in the warmer, less vegetated cities. Additionally, larger-bodied species were most negatively impacted by urbanization across North America,” the study authors wrote.
“Our results suggest that shifting climate conditions could worsen the effects of urbanization on native wildlife communities, such that conservation strategies should seek to mitigate the combined effects of a warming and urbanizing world,” researchers said.
In cities with greener vegetation, diversity and richness (the number of species in a community) tended to be greater and less negatively affected by urbanization. So animals in Phoenix, the least vegetated city, fared worse than animals in the most vegetated city, Sanford, Fla.
A city’s temperature also factored into the equation.
Urbanization in the warm city of Los Angeles was expected to have negative relationships with richness and diversity that were 3.97 and 1.29 times stronger, respectively, than those in Salt Lake City, one of the coldest cities with similar vegetation greenness.
“These apparent temperature-driven differences in urbanization effects may result, in part, from associations between temperature and other ecological characteristics that make cities in different ecoregions distinct, such as vegetation type, structure and evapotranspiration. Urban heat island effects (that is, higher temperatures in highly urbanized areas than in wildlands) may additionally be greater in warmer cities,” the study stated.
Additionally, larger-bodied species were most negatively impacted by urbanization. Researchers are advocating for strategies that mitigate the combined effects of a warming and urbanizing world.
UWIN describes itself as “a collaborative group of diverse researchers housed in institutions across the globe working together to understand urban wildlife.”
Founded in 2017, UWIN applies its research findings in order to achieve conservation goals while aiding urban planning, design and management. Partners of the network are experts in disease, landscape, wildlife ecology, habitat management, education and more.
“UWIN uses this information to provide city planners, wildlife managers and researchers with the tools needed to make cities part of the solution to the biodiversity crisis,” UWIN’s website states.
Species’ functional traits can also influence how landscape change shapes wildlife communities. As researchers expected, larger-bodied mammal species responded more negatively to urbanization. However, the greater mobility of larger species can enable them to better access resources. However, those species are also generally more sensitive to urbanization-driven habitat losses due to their greater space needs and lower reproductive rates, the study authors found.
In their effort to protecting biodiversity from the human-caused change, researchers are campaigning for plans to alter designs. The key, researchers say, is lessening the impact of human-modified habitats by identifying key areas where sustainability goals can be reached and management practices implemented.
“Effectively protecting biodiversity from the impacts of landscape change necessitates that ecological understanding of human-modified habitats be more thoroughly integrated into landscape design processes,” the study authors said.
Researchers are pushing for multiple cities and continents to work together and to identify biodiversity threats so they can mitigate the impacts to “enable declining species and communities to better persist in an increasingly human-dominated world.”
A call to one of the paper’s main authors, Jeffrey Haight, a postdoctoral research scholar at Arizona State University’s School of Life Sciences, was not returned by deadline.