Extensive range loss for the Golden-winged Warbler (Vermivora chrysoptera) has occurred in areas of intrusion by the Blue-winged Warbler (V. cyanoptera) potentially related to their close genetic relationship. We compiled data on social pairing from nine studies for 2,679 resident Vermivora to assess evolutionary divergence. Hybridization between pure phenotypes occurred with 1.2% of resident males for sympatric populations. Pairing success rates for Golden-winged Warblers was 83% and for Blue-winged Warblers was 77%. Pairing success for the hybrid Brewster’s Warbler was significantly lower from both species at 54%, showing sexual selection against hybrids. Backcross frequencies for Golden-winged Warblers at 4.9% was significantly higher than for Blue-winged Warblers at 1.7%. More frequent backcrossing by Golden-winged Warblers, which produces hybrid phenotypes, may contribute to the replacement of Golden-winged by Blue-winged Warblers. Reproductive isolation due to behavioral isolation plus sexual selection against hybrids was 0.966. Our analyses suggest that plumage differences are the main driving force for this strong isolation with reduced hybrid fitness contributing to a lesser degree. The major impact of plumage differences to reproductive isolation is compatible with genomic analyses (Toews et al. 2016), which showed the largest genetic difference between these phenotypes occurred with plumage genes. These phenotypes have maintained morphological, behavioral, and ecological differences during two centuries of hybridization. Our estimate of reproductive isolation supports recognition of these phenotypes as two species. The decline and extirpation of the Golden-winged Warbler in almost all areas of recent sympatry suggest that continued coexistence of both species will require eco-geographic isolation.

Fungi are a key component of tropical biodiversity. Due to their inconspicuous and largely subterranean nature, they are however usually neglected in biodiversity inventories. The goal of this study was to identify the key determinants of fungal richness, community composition, and turnover in tropical rainforests. We tested specifically for the effect of soil properties, habitat, and locality in Amazonia. For these analyses, we used high-throughput sequencing data of short and long reads of fungal DNA present in soil and organic litter samples, combining existing and novel genomic data. Habitat type (phytophysiognomies) emerges as the strongest factor in explaining fungal community composition. Naturally open areas – campinas – are the richest habitat overall. Soil properties have different effects depending on the soil layer (litter or mineral soil) and the choice of genetic marker. We suggest that campinas could be a neglected hotspot of fungal diversity. An underlying cause for their rich diversity may be the overall low soil fertility, which increases the reliance on biotic interactions essential for nutrient absorption in these environments, notably ectomycorrhizal fungi–plant associations. Our results highlight the advantages of using both short and long DNA reads produced through high-throughput sequencing to characterize fungal diversity. While short-reads can suffice for diversity and community comparison, long-reads add taxonomic precision and have the potential to reveal population diversity.