Sagebrush Songbirds Benefit from Sage Grouse Habitat Restoration.

摘要

Over the past 150 years, junipers and pinyon pines have expanded into sagebrush country, often due to fire suppression, historic overgrazing and favorable climatic conditions. Conifer encroachment today is largely an infill issue, as most sites vulnerable to invasion became occupied by trees late in the 1800s and 1900s. Where traditional sagebrush habitat had a few large, old growth conifer trees scattered across the landscape or restricted in clumps, more trees are now moving into the sage-steppe and in some cases completely outcompeting shrubs, grasses and forbs. Roughly 80% of sagebrush sites invaded by conifers are still in the early phases of woodland succession (Phases I and II), where native shrubs and bunchgrasses are common providing a window of opportunity for conservationists to reclaim otherwise suitable habitat. Conifer encroachment has benefited a number of woodland associated bird species, but scientists have long suspected that this happens at the detriment of shrub and grassland dependent bird species – many of which are of greater conservation concern.