Landscape-scale differences among cities alter common species' responses to urbanization

Area of Science:

• Urban Ecology
• Wildlife Conservation
• Landscape Ecology

Background:

• Most urban ecology studies focus on single cities, limiting understanding of broad-scale biodiversity responses.
• Urbanization presents complex challenges for wildlife, with varying impacts based on local and landscape factors.

Purpose of the Study:

• To investigate continent-scale patterns of urban species assemblages across North American cities.
• To quantify the relationship between greenspace availability, housing density, and mammal distribution in urban environments.
• To understand how city-level characteristics modify species' responses to urbanization.

Main Methods:

• Utilized data from a multi-city camera trap survey across 10 North American cities.
• Deployed camera traps at 569 sites between June and August (2016-2018).
• Analyzed the distribution of eight widespread North American mammals in relation to greenspace and housing density.

Main Results:

• Species' responses to urbanization varied with city-scale greenspace and housing density.
• Eastern gray squirrels, fox squirrels, and red foxes shifted from negative to positive responses with >20% green space.
• Raccoons and Virginia opossums shifted from positive to negative responses with >700 housing units/km².
• Species richness declined with urbanization primarily in cities exceeding 700 housing units/km².

Conclusions:

• City design, including increasing green space, can mitigate negative urbanization effects on wildlife.
• Densely populated cities require innovative strategies to enhance wildlife resilience and prevent biodiversity loss.
• Understanding landscape-scale factors is crucial for predicting and managing urban biodiversity.