Browsing by Author "Correia, Edna"
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- Dietary metabarcoding reveals the simplification of bird–pest interaction networks across a gradient of agricultural coverPublication . Silva, Luis P. da; Mata, Vanessa A.; Lopes, Pedro B.; Pinho, Catarina J.; Chaves, Catia; Correia, Edna; Pinto, Joana; Heleno, Ruben H.; Timoteo, Sergio; Beja, PedroAgriculture is vital for supporting human populations, but its intensification often leads to landscape homogenization and a decline in non-provisioning ecosystem services. Ecological intensification and multifunctional landscapes are suggested as nature- based alternatives to intensive agriculture, using ecological processes like natural pest regulation to maximize food production. Birds are recognized for their role in increas- ing crop yields by consuming invertebrate pests in several agroecosystems. However, the understanding of how bird species, their traits and agricultural land cover influ- ence the structure of bird–pest interactions remains limited. We sampled bird–pest interactions monthly for 1 year, at four sites within a multifunctional landscape, fol- lowing a gradient of increasing agricultural land cover. We analysed 2583 droppings of 55 bird species with DNA metabarcoding and detected 225 pest species in 1139 samples of 42 bird species. As expected, bird–pest interactions were highly variable across bird species. Dietary pest richness was lower in the fully agricultural site, while predation frequency remained consistent across the agricultural land cover gradient. Network analysis revealed a reduction in the complexity of bird–pest interactions as agricultural coverage increased. Bird species abundance affected the bird's contribu- tion to the network structure more than any of the bird traits analysed (weight, phe- nology, invertebrate frequency in diet and foraging strata), with more common birds being more important to network structure. Overall, our results show that increasing agricultural land cover increases the homogenization of bird–pest interactions. This shows the importance of maintaining natural patches within agricultural landscapes for biodiversity conservation and enhanced biocontrol.
- Foraging movements and important sites for conservation of the West African Crested Tern Thalasseus albididorsalis breeding in Guinea-BissauPublication . Correia, Edna; Beal, Martin; Gomes, Nélson; Diop, Ngoné; Wambar, Francisco; Dias, Maria P.; Hernandez-Rios, Alfonso; Catry, TeresaAssessing at-sea distributions and behaviour of seabirds to identify critical foraging sites and spatial overlap with potential threats is a major step for delineating conservation guidelines. The West African Crested Tern (Thalasseus albididorsalis) is the most abundant breeding tern in West Africa, nesting from Mauritania to Guinea. Its restricted breeding range and exclusive nesting at coastal low-lying areas, place this species at particular risk of losing suitable breeding and resting sites as a consequence of current global changes, namely, sea-level rise. The at-sea distribution of this species is mostly unknown, and therefore, the specific threats faced are still unidentified. Here, we characterize the foraging behaviour and distribution of West African Crested terns breeding at the world’s second-largest colony of the species, in Guinea-Bissau, by tracking 20 individuals. Overall, terns took an average of 2 trips per day, travelling on average 100 km per trip, but often reaching areas up to 120 km from the colony. Shallow waters, usually not exceeding 10 m in depth, and upwelling areas were mostly used as foraging sites. Nocturnal movements, rarely reported on terns, suggest active foraging at night. Key foraging and resting sites were identified, which altogether may regularly hold 2.5–23% of the global breeding population of the West African Crested Tern. These areas are only partly (ca. 50%) covered by the existing marine Important Bird and Biodiversity Area (IBA). Therefore, our results should be considered in any re-evaluation of the IBA borders.