Individual study: Least Bell’s vireo in restored riparian forests exhibit slow colonisation rates but similar reproductive productivity to those in natural areas
Kus B.E. (1998) Use of Restored Riparian Habitat by the Endangered Least Bell’s Vireo (Vireo bellii pusillus). Restoration Ecology, 6, 75-82
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Restore or create forests
A replicated, controlled study from 1989-1993 in four restoration sites (all established in 1989-1990; all 3-5 ha) and one natural site (16 ha) of riparian forest habitat in California, USA (Kus 1998) found that least Bell’s vireos Vireo bellii pusillus were slow to colonise restored sites and did so at lower abundances (9 pairs/site for restored sites vs. 41 for natural site) but exhibited similar reproductive output to natural areas when they did (56% nest success and 1.6 fledglings/nest for restored sites vs. 46% and 1.3 for natural sites). Vireos foraged in restored sites from the first growing season but they did not establish territories until small patches of vegetation became characteristic of natural nesting areas (colonisation rate was also correlated with the presence of adjacent mature riparian habitat).
Other biodiversity: Restore habitat along watercourses
A replicated site comparison in 1989–1993 in riparian forests along the San Luis Rey and San Diego Rivers, California, USA, found that the endangered Bell’s Vireo Vireo bellii pusillus nested in restored sites, and similar numbers of fledglings were found in restored and remnant sites, even though four of five sites did not meet modelled criteria for nesting habitat. Birds: Similar numbers of fledglings were found in restored and remnant sites, at least along the San Luis Rey River (1.9–4 vs 1–1.4 fledglings/nest; 3–4 vs 1.6–2.4 fledglings/breeding pair), and nests were established within 1–5 years. Plants: By 1993, the vegetation at one of five sites met the modelled criteria (e.g., height and cover) for Bell’s Vireo nesting habitat. Methods: Five restored sites (3–13 ha) were surveyed along the San Luis Rey River (three sites, established in 1989) and the San Diego River (two sites, established in 1990). The sites were planted with willows and/or other species, based on the natural habitat of Bell’s Vireo. These sites were compared to natural habitats along these rivers. Birds were surveyed every 1–2 weeks. Nests were surveyed between mid-March and August.