Multiple facets of avian diversity in pine forests along an urban-agricultural gradient

• Published in: Biodiversity and conservation 2022-02, Vol.31 (2), p.497-516
• Main Author: Lee, Myung-Bok
• Format: Article
• Language: English
• Subjects: Agricultural industry; Agriculture; Biodiversity; Biological diversity; Biomedical and Life Sciences; Breeding; Climate Change/Climate Change Impacts; Coniferous forests; Conservation Biology/Ecology; Dimensions; Distance; Ecology; Forest and plantation biodiversity; Forests; Forests and forestry; Grasslands; Guilds; Habitats; Hardwoods; Insectivores; Intensive farming; Landscape; Life Sciences; Livestock breeding; Omnivores; Original Paper; Pasture; Phylogenetics; Phylogeny; Pine; Plant cover; Taxonomy; Urban agriculture; Urban development; Urban sprawl; Vegetation; Vegetation cover
• ISSN: 0960-3115; 1572-9710
• DOI: 10.1007/s10531-021-02345-x

Increasing land conversion of agriculture and forest by urban growth in the southern United States has altered the landscape matrix surrounding pine forests, creating varying mixtures of urban and agricultural cover types. I investigated the avian diversity-environment relationship in the southern pine forests along an urban-agriculture-wildland gradient by quantifying multiple dimensions of biodiversity: taxonomic (Shannon-Wiener index), functional (RaoQ and its standardized effect size), and phylogenetic (mean pairwise distance, mean nearest taxon distance, and their standardized effect size) diversity. I also considered habitat guilds and single traits correlated with RaoQ. I used breeding bird data collected at 162 pine stands in Georgia. Taxonomic and functional diversity increased with agricultural cover within the landscape (1 km-radius area). In particular, shrub habitat guild and shrub nesters showed a strong positive response to the variable. Insectivores and tree nesters (two predominant traits in pine forests) responded negatively to urban and agricultural covers. Both taxonomic and functional diversity decreased and increased with increasing hardwood vegetation cover and herbaceous vegetation cover within a stand, respectively. Pine-grassland and shrub habitat guilds, omnivores, and shrub nesters also showed the similar responses to these variables. Phylogenetic diversity metrics were not associated with environmental variables. The findings of this study suggest that open habitat features within a stand are important to promote functional diversity as well as taxonomic diversity in pine forests. They also indicate that agricultural matrix does not act as an environmental filter and low to moderate levels of less intensive agricultural (hay/pasture) matrix may improve avian diversity.