Parásitos gastrointestinales de aves silvestres en un ecosistema ribereño urbano tropical en Heredia, Costa Rica / Gastrointestinal parasites of wild birds in a tropical riverine urban ecosystem in Heredia, Costa Rica

Resumen En las zonas urbanas, los ríos brindan diversos servicios ecosistémicos, entre ellos, funcionan como corredores biológicos interurbanos, permitiendo a las aves trasladarse y refugiarse en medio de la ciudad. Sin embargo, los altos niveles de contaminación las exponen, e incluso al ser humano, a diversos problemas de salud. De aquí la importancia de realizar diagnósticos ambientales que permitan identificar alteraciones y mitigarlos de forma oportuna. En este estudió se da un primer diagnóstico de la situación parasitaria de las aves silvestres del río Pirro ubicado en un entorno urbano, fragmentado y con altos niveles de contaminación superficial del agua. El muestreo se llevó a cabo en la parte alta y media del río Pirro en Heredia, Costa Rica. Se utilizaron redes de niebla para la captura de las aves, y se les realizó un examen objetivo general (EOG) para revisar su estado de nutrición e hidratación, así como su estado físico; además, se recolectaron muestras de heces para la caracterización de los parásitos gastrointestinales (PGI). Este procedimiento se realizó a 158 aves, correspondientes a 30 especies, se identificaron tres grupos de estos: protozoarios, nematodos y cestodos. Los porcentajes de infección más altos estuvieron representados por los coccidios, con 97.6 %, seguido de los nematodos y cestodos con un 2.4 %. Dentro del grupo de los coccidios se logró identificar: Eimeria spp., Isospora spp., en los nemátodos: a nivel de grupo Strongylida y a nivel de género: Capillaria spp. Y para los céstodos: Choanotaenia spp. El EOG resultó de regular a bueno en todos los individuos capturados sin embargo, mediante el modelo de regresión lineal general (General Lineal Model) se identificó que la cavidad oral de las aves y el estado del plumaje, podrían ser las variables más relacionadas con el porcentaje de infección por parásitos gastrointestinales, esto debido a que la cavidad oral es la vía principal de ingesta para el ave, así como el estado del plumaje evidencia su vigor.

Abstract In urban ecosystems, rivers provide various ecosystem services, among them, serving as interurban biological corridor, allowing birds to move and shelter in the middle of the city. However, high levels of pollution expose them, and even humans, to several health problems. Hence the importance of performing environmental diagnoses that allows to identify alterations and mitigate them in a timely manner. This study provides a first diagnosis of the parasitic situation of wild birds along the Pirro river which is located in an urban environment, fragmented and with high levels of surface water pollution. The sampling was carried out at the upper and middle part of the Pirro river in Heredia, Costa Rica. Mist-nets were used to capture the birds, and a general objective exam (GOE) was conducted in order to evaluate their nutritional and hydration state, as well as their physical state. In addition, stool samples were collected in order to characterize the gastrointestinal parasites (GPI). This procedure was carried out on 158 birds, belonging to 30 species, three PGI groups were identified: protozoa, nematodes and cestodes. The highest percentages of infection were represented by coccidia, with 97.6 %, followed by nematodes and cestodes with 2.4 %. Within the group of coccidios, it was possible to identify Eimeria spp., Isospora spp., in the nematodes: at the Strongylida group level and at the Capillaria spp., and for the cestodes: Choanotaenia spp. GOE resulted regular-to-good in all individuals captured, however, a general linear model was used to identify that the oral cavity and the state of the plumage could be the more linked variables with the percentage of infection by gastrointestinal parasites in birds, due to the fact that the oral cavity is the bird's main route of ingestion, as well as the state of the plumage shows its vigor. Rev. Biol. Trop. 66(2): 788-798. Epub 2018 June 01.

Avifauna associada a um trecho urbano do rio Sorocaba, Sudeste do Brasil / Avifauna associated to an urban extend of the Sorocaba river, Southeastern Brazil

Este estudo teve como objetivo caracterizar a avifauna associada ao rio Sorocaba, um típico rio urbano, do sudeste do Brasil. Ele atravessa a cidade com o mesmo nome, ao longo do qual, várias atividades humanas são realizadas como recreação e pesca. Lá, várias espécies de aves devem encontrar locais para descanso, alimentação e nidificação. As aves foram observadas semanalmente, de setembro de 2008 a setembro de 2009 por meio de 16 pontos fixos (A1 a A16). O levantamento quantitativo registrou 65 espécies (32 passeriformes e 33 não - passeriformes), sendo que a família mais bem representada foi Tyrannidae (n = 9). As espécies mais freqüentes foram Egretta thula, Amazonetta brasiliensis, Vanellus chilensis, Pitangus sulphuratus, Ardea alba e Pygochelidon cyanoleuca (FO = 100%). Os maiores valores do índice pontual de abundância foram 46,5 (1626 contatos) para Pgochelidon cyanoleuca, 14,4 (500 contatos) para Phalacrocorax brasilianus e 12,9 (452 contatos) para Amazonetta brasiliensis. As categorias tróficas mais representativas foram dos insetívoros (n = 26), piscívoros (n = 11) e onívoros (n = 10). A análise de agrupamento revelou a existência de três pares de pontos muito semelhantes (100 e 95% semelhança). Diferenças conspícuas na composição da fauna de aves ao longo da área estudada foram detectadas, provavelmente devido às suas características ambientais e do grau de perturbação humana. Além disso, diferenças significativas nos avistamentos foram observadas entre as estações de seca e chuva, provavelmente em função das atividades reprodutivas e migratórias e do aumento na disponibilidade de recursos alimentares, que supostamente ocorrem no período chuvoso. Neste sentido, práticas conservacionistas devem permitir a manutenção a heterogeneidade de habitats, recuperação da vegetação ripária, praias e banhados, assim como o planejamento efetivo das atividades humanas em seu entorno.

This study aimed to characterize the avifauna associated to the Sorocaba River, a typical urban river in Southeastern Brazil. It crosses the city having the same name, along which different human activities are carried out as recreation and fishing. There, several bird species might find sites for resting, feeding and nesting. We surveyed birds weekly, from September 2008 to September 2009, by 16 point counts (A1 to A16). The quantitative survey registered 65 species (32 Passeres and 33 non-Passeres), and the most well-represented family was Tyrannidae (n = 9). The most frequent species were Egretta thula, Amazonetta brasiliensis, Vanellus chilensis, Pitangus sulphuratus, Ardea alba and Pygochelidon cyanoleuca (FO = 100%). The higher abundance index values were 46.5 (1626 contacts) for Pygochelidon cyanoleuca, 14.4 (500 contacts) for Phalacrocorax brasilianus and 12.9 (452 contacts) for Amazonetta brasiliensis. The most representative trophic categories were insectivores (n = 26), piscivores (n = 11) and omnivores (n = 10). The cluster analysis revealed the existence of three very similar pairs of points (100 and 95% of information remaining). Conspicuous differences in the composition of bird fauna along the studied area were detected, probably due to its environmental characteristics and the degree of human disturbance. Moreover, significant differences were observed between the sightings of dry and wet seasons, probably due to the reproductive and migratory activities and an increased availability of food resources that is supposed to happen in the wet season. In this sense, conservation practices should provide the maintenance of habitat heterogeneity, recovering the riparian forests, beaches and marshes, and an effective planning of human activities in their surroundings as well.