Nonnative, Noninvasive Woody Species Can Enhance Urban Landscape Biodiversity

Article Figures & Data

Table 1.

Study sites represented in the literature review.

Table 2.

Site and vegetation traits associated with animal species abundance and richness^{^z}.

Vegetation trait	Birds	Insects	Mammals	Reptiles
Habitat structure (canopy cover, vertical diversity, tree and shrub density and diversity)	X	X	X	X
Larger and/or connected sites	X	X	X
Older, larger trees	X	X	X	X
Hollow trees	X	X	X	X
Woody debris				X
Moderately disturbed sites	X
Profusely flowering species with seasonal diversity		X
Native vegetation^{^y}	X	X
Herbaceous/grass cover	X		X	X
Permanent water source	X	X	X

↵^z The absence of an association means only that none were found in the literature surveyed.
↵^y Specialists only.

Table 3.

Selecting tree and shrub species to enhance ecosystem biodiversity.

Goal	Activity	Information to collect	References
Determine the need for new trees	Conduct tree surveys	Age distribution, canopy cover, percent natives, species diversity
Determine potential environmental stresses	Evaluate site conditions	Air pollution, drought, heat, light, salt, soil conditions, pests, disease	Pair 1994; Kirnbauer et al. 2009
Determine community needs for specific resources	Diversify plant palette	Food, nesting habitat needs for native species of interest
Determine potential invasiveness	Research possible introductions using decision tree	Any relevant plant introduction regulations; data on invasiveness of related species	Reichard and Hamilton 1997; Kirnbauer et al. 2009; Zhu et al. 2010

Table 4.

Managing urban greenspaces to enhance native community biodiversity.

Goal	Activity	References
Reduce invasive plant species	* Plant alternative resources before removing invasives with food or nesting value * Remove invasives favored for nesting during the winter * Remove invasives favored for food only when ample alternatives present	Eliasaro et al. 2009; Kath et al. 2009; Gleditsch and Carlo 2011; Adhikari et al. 2012a;
Increase tree and shrub species diversity	* Plant native as well as non-invasive introduced species	Santamour 1978
Maintain a vertically diverse assemblage of vegetation	* Plant more ground and shrub vegetation for bird habitat * Plant trees in groups rather than as isolates * Retain deadwood and other nesting structures in place when possible	Oneal and Rotenberry 2008; Suarez-Rubio and Thomlinson 2009; Adhikari et al. 2012b
Improve tree size distribution	* Protect middle-aged trees to ensure longevity * Retain old, large trees * Use small “urban” tree species sparingly	Marzluff and Ewing 2001; Landmann 2006; Nagendra and Gopal 2011; Adhikari et al. 2012b
Enhance ecosystem edges	* Increase diversity of plants in edge habitats * Reduce management of edges (e.g., no mowing, pesticide application, etc.)	Marzluff and Ewing 2001; Stewart et al. 2004; Roberts et al. 2007; Shwartz et al. 2008; Vallet et al. 2010
Reduce predation on native animal species	* Reduce managed, open lawns	Marzluff and Ewing 2001
Improve soil habitat for insects, reptiles, and mammals	* Reduce soil compaction with organic mulch	Garden et al. 2007