Response of avian communities to disturbance by an exotic insect in spruce-fir forests of the southern Appalachians

• Published in: Conservation biology 1998-02, Vol.12 (1), p.177-189
• Main Authors: Rabenold, K.N, Fauth, P.T, Goodner, B.W, Sadowski, J.A, Parker, P.G
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; ANIMAL SALVAJE; ANIMAL SAUVAGE; Animal, plant and microbial ecology; Aviculture; BIODIVERSIDAD; BIODIVERSITE; BIODIVERSITY; Biological and medical sciences; BIRDS; BOSQUE DE CONIFERAS; BOSQUES; CAROLINA DEL NORTE; CAROLINE DU NORD; COMMUNAUTE VEGETALE; COMUNIDADES VEGETALES; CONIFEROUS FORESTS; Conservation biology; Deciduous forests; DREYFUSIA PICEAE; ENVIRONMENTAL IMPACT; Forest ecology; Forest habitats; FORESTS; FORET; FORET RESINEUSE; Fundamental and applied biological sciences. Psychology; IMPACT SUR L'ENVIRONNEMENT; IMPACTO AMBIENTAL; Mountain forests; NATIONAL PARKS; NORTH CAROLINA; OISEAU; PAJAROS; PARC NATIONAL; PARQUES NACIONALES; PLANT COMMUNITIES; SPECIES DIVERSITY; Synecology; TENNESSEE; Terrestrial ecosystems; Warblers; WILD ANIMALS
• ISSN: 0888-8892; 1523-1739
• DOI: 10.1046/j.1523-1739.1998.96085.x

The avian community of montane coniferous forests changed substantially over 21 years in response to the introduction of the balsam woolly adelgid insect (Adelges piceae) and the resulting death of endemic Fraser fir trees (Abies fraseri). These relict forests are at the southern limit of their distribution on the highest ridges of the southern Appalachian Mountains. We combined a historical study at Mount Collins in the Great Smoky Mountains with a geographic comparison of sites within five southern Appalachian mountain ranges variably affected by the adelgid. At Mount Collins, fir was virtually eliminated and canopy cover reduced to half its previous level. Long-term data from Mount Collins showed that the combined density for all breeding birds also declined by half. Of the common territorial species present in 1974, 10 of 11 declined, 6 by more than 50%. Some species are near local extinction. Canopy- and subcanopy-foraging species declined more than near-ground and trunk-foraging species. In addition, invasions of birds characteristic of open and disturbed forests have diluted the boreal character of the avifauna. These changes are consistent with two other long-term studies and are not explained by regional population trends. In the other southern Appalachian mountain ranges, where habitat is not as extensive, the adelgid invasion resulted in greater declines in avian abundance, stronger effects on sensitive species, and more pronounced invasions by successional species. Sensitive species in the southern Appalachian studies were also strongly affected in other studies of forest disturbance by fire and logging. The extent of relatively pristine spruce-fir forest and the population pools in other forest types in the Great Smoky Mountains appear to have buffered the effects of forest decline on the bird community.