Successional models as guides for restoration of riparian forest understory

Published source details McClain C.D., Holl K.D. & Wood D.M. (2011) Successional models as guides for restoration of riparian forest understory. Restoration Ecology, 19, 280-289.
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This study is summarised as evidence for the following.

	Action	Category
	Other biodiversity: Restore habitat along watercourses Action Link

Other biodiversity: Restore habitat along watercourses

A replicated, before-and-after site comparison in 1989–2008 in riparian forests along the Sacramento River, California, USA, found fewer native species, with lower ground and canopy cover, and more exotic species in restored sites, compared to remnant sites. Plants: Fewer native species (5–7 vs 10 species; 21–32% vs 65% relative cover, 48–56% vs 87% frequency) and more exotic species (15–16 vs 9 exotic species; 79–67% vs 34% relative cover; 91–84% vs 56% frequency) were found in the 15 sites planted with overstorey species, compared to forest remnants. Fewer native species (4–6 vs 10 species; 16–19% vs 65% relative cover; 41–42% vs 87% frequency) and lower overstorey cover (31–39% vs 79%) were found in the 20 sites planted in 1997–2003, compared to forest remnants, in some comparisons. Implementation options: Between 2001 and 2007, increases in native species (5 vs 7 species) and overstorey cover (29% vs 60%) were found in the 15 sites planted with overstorey species in 1989–1996. Similar numbers of native species (5–6 species, 16–29% relative cover; 41–65% frequency) and similar overstorey cover (31–39%) were found in plots planted with understorey species at high or low densities in 1997–2003. Lower overstorey cover (31% vs 64) was found in plots planted with both overstorey and understorey species, compared to overstorey species, in one of two comparisons (31% vs 64%). Methods: Native overstorey species (trees and shrubs) were planted on 15 sites in 1989–1996 and 20 sites (14 of which were also planted with understory species, at high or low densities: herbs, vines, grasses, and low shrubs) in 1997–2003 (5–60 ha sites; 530–1,300 plants/ha; disked, planted, mown, irrigated, and weeds controlled for three years). Plants were surveyed in plots planted with overstorey species (in 2001 and 2007) or non-woody vegetation (2007) and in 10 forest remnants (15–20 ha, five sites in 2001, five sites in 2008). Vegetation was surveyed in quadrats (1 x 1 m, 20–80 quadrats/site) along a transect (part of a 40 x 80 m grid).