Green facades provide habitat for arthropods on buildings in the Washington, D.C. metro area

Green facades are a relatively new green building technology particularly relevant in urban areas where ground-level space is limited and vegetation is scarce. Increased wildlife habitat is often proposed as a benefit of the technology, but little experimental data exists supporting this claim. An observational field study tested whether green facades had a higher abundance or diversity of arthropods than non-vegetated building facades, and whether abundance and diversity values could be explained by specific vegetation characteristics. Green walls contained 16 to 39 times more arthropods per meter squared than adjacent blank walls. Measures of arthropod richness, Shannon-Wiener diversity, and order-area curve slopes were significantly higher on green walls than on blank walls. Arthropod abundance and richness were most strongly correlated with habitat availability and vine canopy thickness. Herbivores, predators, parasitoids, and detritivores were found on the green facades. Results indicate that green facades increase ecological habitat in urban environments.