The actions urban forest managers, ecologists, and com-
munity stewards undertake to review and comment
on new development plans and to plant, remove, and
otherwise manage trees in cities have implications for
local wildlife habitat and biodiversity. Far too often,
these influences do not receive enough attention unless
threatened and endangered species are present, or if
residents make it an issue. This article puts a spotlight on
the impacts of urbanization on ecological communities
and biodiversity, and how urban and community plans,
policies, and actions can make a difference in improving
the habitat function of urban trees and forests.
Native species
Urbanization has negatively impacted biodiversity glob-
ally, and the expansion of cities poses continuing threats
to native species survival (Seto et al. 2012). However,
while cities can appear devoid of wildlife, the impact of
urbanization is not universal across species. For example,
in some urban areas, native birds like American Robins
and mammals like raccoons thrive. Urban areas help
support the conservation of global biodiversity, and
the management of greenspaces determines the avail-
ability of habitat for native species (Lepczyk et al. 2017).
Conserving and managing wildlife habitat is increas-
ingly important and challenging as cities continue to
expand and meet the needs of people (Aronson et al.
2017). Just as we need to make space for street trees in
the built environment, it is important that we protect
spaces like local parks, woodland preserves, and forest
patches where native plants and biodiversity can thrive.
Ecosystem services and disservices
Urban wildlife populations provide essential ecosystem
services and benefits for people with increasing efficacy
as animal biodiversity increases (Schwarz et al. 2017).
Examples of services include plant pollination and seed
dispersal that help promote afforestation. Birds and
mammals scavenge carrion and insect pests, such as
ticks and mosquitoes that carry vector-borne diseases
(Cardinale et al. 2012). Arthropods, such as spiders, feed
on pests and parasites and complete decomposition
and consumption of waste (Youngsteadt et al. 2015).
While it is true that people benefit from increased
animal biodiversity, the perceptions of the benefits
may vary from person to person (Larson et al. 2019).
Additionally, urban green spaces are not always >>
From the USDA Forest Service and partners
Urban Forests as Habitat
for People and Wildlife
By Alexandreana Cocroft, USFS Resource Assistant; Susannah B. Lerman, USFS Research Ecologist;
Patrice N. Klein, USFS National Program Lead Fish and Wildlife Health; Phillip Rodbell, USFS
National Program Lead Urban Forest Research
24 CityTREES
