Determining Effective Riparian Buffer Width for Nonnative Plant Exclusion and Habitat Enhancement

Table 1

Summary of repeated measures ANOVA models on nonnative prevalence across multiple riparian buffer widths in Delaware and Pennsylvania, 2007-2008. We tested for within-sample effect of distance from buffer edge as well as the interaction between distance and total riparian buffer width, basal density at sampled distance, and canopy coverage at sampled distance. Stars indicate significance (𝑃≤0.10). We further tested for trends across buffer width exhibiting significant (𝑃≤0.10) linear, quadratic, or cubic relationships.

Species	Repeated measures ANOVA model	Distance (m)
		10	20	35	55
		𝑛=31	𝑛=24	𝑛=20	𝑛=12
Japanese honeysuckle	Distance	—	—	—	—
	Distance contrast	—	—	—	—
	Distance ∗ total buffer width	—	—	—	—
	Distance ∗ basal density	—	—	—	—
	Distance ∗ canopy coverage	—	—	—	—
	Between sample effect	—	—	—	—
Garlic mustard	Distance	∗	—	—	—
	Distance contrast	Linear	—	—	—
	Distance ∗ total buffer width	—	∗	—	—
	Distance ∗ basal density	—	—	—	—
	Distance ∗ canopy coverage	∗	—	—	—
	Between sample effect	—	—	—	—
Multiflora rose	Distance	—	∗	—	∗
	Distance contrast	—	Quadratic	—	Linear
	Distance ∗ total buffer width	—	∗	—	—
	Distance ∗ basal density	—	—	—	—
	Distance ∗ canopy coverage	—	∗	—	∗
	Between sample effect	—	—	∗	—
Bittersweet	Distance	∗	∗	—	—
	Distance contrast	Linear	Cubic	—	—
	Distance ∗ total buffer width	—	∗	—	—
	Distance ∗ basal density	—	—	—	—
	Distance ∗ canopy coverage	∗	∗	—	—
	Between sample effect	—	—	—	—