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Because of the significant impacts on both human interests and bird conservation, it is imperative to identify patterns and anticipate drivers of human-bird conflicts (HBCs) worldwide. Through a global systematic review, following the PRISMA 2020 guidelines, we analyzed the socioeconomic factors and bird ecological traits driving the degree of knowledge and extent of HBCs. We included 166 articles published from 1971 to 2020 in our analyses through which we built a profile of the socioeconomic conditions of 52 countries with reported conflicts and the ecological traits of the 161 bird species involved in HBCs. Although HBC expanded worldwide, it had the greatest impact in less-developed countries (estimate 0. 66 [SE 0.13], p0.05), where agriculture is critical for rural livelihoods. Species with a relatively greater conflict extent had a relatively broader diet (estimate 0.80 [SE 0.22], p0.05) and an increasing population trend (estimate 0.58 [SE 0.15], p0.05) and affected human interests, such as agriculture and livestock raising. In countries with greater biodiversity, HBCs caused greater socioeconomic impacts than in more developed countries. Our results highlight the importance of understanding and addressing HBCs from multiple perspectives (ecological, sociocultural, and political) to effectively protect both biodiversity and local livelihoods.El desarrollo socioeconómico y las características ecológicas como pronosticadores de los conflictos entre aves y humanos Resumen Debido a los impactos significativos sobre los intereses humanos y la conservación de las aves, es imperativo identificar patrones y anticiparse a las causas de los conflictos humano-aves (CHA) a nivel mundial. Por medio de una revisión sistemática, siguiendo los lineamientos de PRISMA 2020, analizamos los factores socioeconómicos y las características ecológicas de las aves que impulsan el grado de conocimiento y la extensión de los CHA. Incluimos 166 artículos publicados desde 1971 hasta 2020 en nuestros análisis, con los cuales construimos un perfil de las condiciones socioeconómicas de 52 países con reportes de conflictos y de las características ecológicas de 161 especies de aves involucradas en los CHA. Aunque los CHA se expandieron mundialmente, tuvieron un mayor impacto en los países menos desarrollados (estimado 0. 66 [ES 0.13], p0.05), en donde la agricultura es crítica para el sustento rural. Las especies con una extensión de conflicto relativamente más larga también contaban con una dieta más amplia (estimado 0.80 [ES 0.22], p0.05) y una tendencia poblacional en aumento (estimado 0.58 [ES 0.15], p0.05), lo que afectó los intereses humanos, como la agricultura y la cría de ganado. En los países con mayor biodiversidad, los CHA ocasionaron impactos socioeconómicos mayores que en los países más desarrollados. Nuestros resultados resaltan la importancia de abordar y entender los CHA desde múltiples perspectivas (ecológica, sociocultural, política) para proteger de manera efectiva tanto a la biodiversidad como a los sustentos locales.

Potential ecological risk by arsenic in the available fractions of the sediment in the river, lagoon, mixing zone and beaches bordering the mouth of the Loa River, north of Chile, was determined based on low and medium range effects. The distribution constant, geoaccumulation index and As enrichment factor were deduced. To estimate reactive As, three simple extraction procedures were compared. In order to obtain the risk assessment code, the first two stages of sequential Tessier extraction and bioavailability were applied according to the modified BCR schema. The salty and alkaline continental waters showed a reducing character, low OD, N/P and Cu, but high As (1.13-1.80 mg/l), diluted in the sea at 0.012 mg/L. The neutral continental sediments presented low organic matter (2-6%), acceptable levels of N/P, CaCO 3 (5.3-31%) and Cu, but elevated As (516-856 mg/kg). As reached levels of 20 mg/kg in marine sediments. According to the geoaccumulation index values, there was terrestrial but not marine pollution, although the enrichment factors confirm the presence of high potential risk at the river mouth. Simple extractions and the risk assessment code point to As as mobile and bioavailable. The level of As in the fluvial sediment associated with interchangeable, reducible and oxidizable fractions confirm potential risk for the ecosystem under alkaline and reducing conditions. On the other hand, in the coastal border As was found associated mainly with residual and interchangeable fractions, which reduces this potential risk.

Understanding diversity patterns along environmental gradients lies at the heart of community ecology and conservation. Previous studies have found variation in bird diversity and density along "natural" elevational gradients in the Tropical Andes Hotspot. However, there is still a lack of knowledge about how bird communities respond to traditional land-use patterns, in association with other multiple drivers, along elevations. In the present study, we investigated biotic, abiotic and anthropogenic sources of variation associated with bird species diversity, density and turnover along a 3000-m elevational gradient, in southern limit of the Tropical Andes Hotspot, northern Chile. Over four seasons, we conducted 472 bird point count surveys and established 118 plots distributed across the Desert, Pre-Puna, Puna and High-Andean belts, where biotic, abiotic and anthropogenic factors were measured. We used mixed-effects models to estimate alpha diversity and multinomial Poisson mixture models to estimate species density, accounting for detectability. Species diversity and density increased until 3300 masl and then declined. This type of elevational pattern is characteristic of dry-based mountains, where environmental conditions are suitable at mid-elevations. Habitats shaped by traditional Aymara indigenous agriculture, associated with relatively high vegetation heterogeneity, hosted the highest values of bird diversity and density. Species turnover was structured by habitat type, while elevational ranges of most species were restricted to three relatively discrete assemblages that replaced each other along the gradient. Our study revealed a hump-shaped relationship between elevation and bird diversity and density in the Dry Tropical Andes Biodiversity Hotspot, supporting a diversity pattern characteristic of dry-based mountains of the world. Traditional Aymara agriculture may have constructed ecological niches for biodiversity at mid-elevations, enhancing vegetation heterogeneity, thus providing resources for resident and rare species. Increasing loss of traditional land-use may present a threat to the bird community in the Tropical Andes Hotspot.