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Conservation programs need improved tools to measure the recovery of animal diversity across restoration gradients. We used soundscapes and expert identifications of bird species to calculate niche position (i.e., mean of environmental conditions across all areas a species occupies) and niche breadth (i.e., the standard deviation of the species distribution) along a recovery gradient; from agriculture to early (up to 20 yrs) and late (up to 38 yrs) recovery, to old-growth forests. Our survey included 323 bird species and was conducted in 66 plots in the lowland Chocoan tropical rainforest in Ecuador where less than 11% of the forest remains intact, and large areas are currently undergoing regeneration post-abandonment. First, we validated our niche metrics by contrasting them against independent global categories of forest density dependency. We then explained the niche metrics of the bird species with different ecological traits, gathered from the literature, reflecting species-specific primary diet, morphology and distribution, and accounting for the phylogenetic relatedness of species. Finally, we explored the phylogenetic signal present in bird species’ ecological traits and recovery niche metrics. Niche position and breadth across the recovery gradient closely followed global categories of forest density dependency. However, our approach provided a more fine-scaled sorting of bird species in forest plots categorized as late recovery and old-growth. Granivorous birds occupied niche positions in active cacao and pasture plots and were replaced by frugivorous birds in older regeneration plots. Along the recovery gradient, tail length and handwing index decreased with niche position, supporting previous observations that birds in old-growth forests are less mobile. Birds in old-growth forests had smaller global distribution ranges than birds in agricultural plots. Finally, the latitudinal distribution of birds in the study area averaged south of the equator, with birds in old-growth plots averaging latitudinal centroids in wet forests north of the equator, whereas birds in agriculture plots averaged latitudinal centroids further south of the country, towards the dry and open Tumbesian forest. Frugivores, invertivores and vertivores had broader niche breadths, but these decreased (marginally) with tail length. We suggest these recovery niche metrics as a potentially powerful tool for the rapid assessment of the recovery process, which might support conservation strategies such as biodiversity credits, compensation payments, and strategic land purchases. With the increasing availability of information-intensive models for bird species identification, such as deep learning artificial intelligence, our new niche metrics open the avenue for rapid assessment of tropical biodiversity and new conservation areas at larger scales.

Army ants are widely recognized as keystone species in neotropical rainforests due to their role as important arthropod predators. Their large‐scale raids involve thousands of workers scouring the forest floor in pursuit of prey, primarily capturing other invertebrates. Up to 20 species of army ants coexist in a rainforest, and dietary niche differentiation has been proposed as a mechanism to alleviate competition among them. Based on only a handful of study sites, however, our understanding of the precise dietary preferences and the extent of niche differentiation remains notably limited. In this study, we aimed to expand our knowledge of army ant communities by resolving an Ecuadorian predation network consisting of 244 prey species and 13 army ant species representing the five known neotropical army ant genera: Cheliomyrmex, Eciton, Labidus, Neivamyrmex, and Nomamyrmex. We collected 2156 prey items from 180 army ant raids/emigrations, and of these, we identified 1945 prey items to the family level, 1313 to the genus level, and 664 to the species level based on morphological identifications and DNA barcodes. Prey consisted primarily of other ants (1843 prey items; 153 ant species), to the largest part ant brood (N = 1726). Hence, most army ant species chiefly plundered the nests of other ants, while the three swarm raiding species, that is, Lab. praedator, Lab. spininodis, and Ec. burchellii, exhibited a relatively high proportion of non‐ant invertebrate prey in their diet. The predation network showed a high degree of specialization (H2′ = 0.65), characterized by little dietary niche overlap among sympatric species. We compared the Ecuadorian network with one previously studied in Costa Rica and found that, despite the large geographic distance, prey preferences remained remarkably similar. We discovered species‐specific preferences for captured ant genera and species, despite some species turnover in both army ants and prey. Additionally, army ants also exhibited consistent spatiotemporal raiding preferences across study sites. In conclusion, predation preferences within army ant communities exhibited consistency in multiple niche dimensions across two distant neotropical rainforests, suggesting a notable level of predictability within army ant predation networks. [ABSTRACT FROM AUTHOR]

Abstract Army ants are widely recognized as keystone species in neotropical rainforests due to their role as important arthropod predators. Their large‐scale raids involve thousands of workers scouring the forest floor in pursuit of prey, primarily capturing other invertebrates. Up to 20 species of army ants coexist in a rainforest, and dietary niche differentiation has been proposed as a mechanism to alleviate competition among them. Based on only a handful of study sites, however, our understanding of the precise dietary preferences and the extent of niche differentiation remains notably limited. In this study, we aimed to expand our knowledge of army ant communities by resolving an Ecuadorian predation network consisting of 244 prey species and 13 army ant species representing the five known neotropical army ant genera: Cheliomyrmex, Eciton, Labidus, Neivamyrmex, and Nomamyrmex. We collected 2156 prey items from 180 army ant raids/emigrations, and of these, we identified 1945 prey items to the family level, 1313 to the genus level, and 664 to the species level based on morphological identifications and DNA barcodes. Prey consisted primarily of other ants (1843 prey items; 153 ant species), to the largest part ant brood (N = 1726). Hence, most army ant species chiefly plundered the nests of other ants, while the three swarm raiding species, that is, Lab. praedator, Lab. spininodis, and Ec. burchellii, exhibited a relatively high proportion of non‐ant invertebrate prey in their diet. The predation network showed a high degree of specialization (H2′ = 0.65), characterized by little dietary niche overlap among sympatric species. We compared the Ecuadorian network with one previously studied in Costa Rica and found that, despite the large geographic distance, prey preferences remained remarkably similar. We discovered species‐specific preferences for captured ant genera and species, despite some species turnover in both army ants and prey. Additionally, army ants also exhibited consistent spatiotemporal raiding preferences across study sites. In conclusion, predation preferences within army ant communities exhibited consistency in multiple niche dimensions across two distant neotropical rainforests, suggesting a notable level of predictability within army ant predation networks.