RESUMO
Geranoaetus polyosoma (Quoy & Gaimard, 1824) is a diurnal raptor widely distributed in South America. Although the trophic ecology of this bird has been more studied in the southern extreme of its range, little information is available on its dietary response to prey supply in desert environments. In the present study, we report on the trophic ecology of G. polyosoma in a sub-urban desert zone in northern Chile, with the following objectives: (1) to quantitatively describe its diet and (2) to determine its dietary selectivity in response to prey supply in the study area. The diet of G. polyosoma consisted mainly of rodents (97.2%). A greater preference (p 0.05) was observed for the following large prey items (> 19.5 g): two native rodent species, Phyllotis xanthopygus (Waterhouse, 1837) and Eligmodontia puerulus (Philippi, 1896); and two introduced rodent species: Rattus rattus (Linnaeus, 1769) and R. norvegicus (Berkenhout, 1769).
Assuntos
Animais , Dieta/veterinária , Falcões , Preferências Alimentares , Roedores , ChileRESUMO
Geranoaetus polyosoma (Quoy & Gaimard, 1824) is a diurnal raptor widely distributed in South America. Although the trophic ecology of this bird has been more studied in the southern extreme of its range, little information is available on its dietary response to prey supply in desert environments. In the present study, we report on the trophic ecology of G. polyosoma in a sub-urban desert zone in northern Chile, with the following objectives: (1) to quantitatively describe its diet and (2) to determine its dietary selectivity in response to prey supply in the study area. The diet of G. polyosoma consisted mainly of rodents (97.2%). A greater preference (p 0.05) was observed for the following large prey items (> 19.5 g): two native rodent species, Phyllotis xanthopygus (Waterhouse, 1837) and Eligmodontia puerulus (Philippi, 1896); and two introduced rodent species: Rattus rattus (Linnaeus, 1769) and R. norvegicus (Berkenhout, 1769).(AU)
Assuntos
Animais , Roedores , Falcões , Preferências Alimentares , Dieta/veterinária , ChileRESUMO
The South American grey fox Lycalopex griseus is a canid widely distributed in southern South America; however, some aspects of its biology are still poorly known. We studied the diet and density of L. griseus in the Lago Peñuelas Biosphere Reserve, in Central Chile. The trophic niche breadth was B = 6.16 (Bsta = 0.47) and prey diversity was H' = 2.46 (Hmax ' = 3.17, J' = 0.78). The highest proportions of prey consumed in the diet were Oryctolagus cuniculus (52.21%) and other mammals (32.78%). We compared these results with a latitudinal gradient of diet results for this species in Chile. L. griseus eats mostly mammals (>90% of total prey), consuming the rodent Phyllotis darwini and reptiles in the northern zone; Oryctolagus cuniculus, Octodon degus and Abrocoma bennetti in the central zone; Abrothrix spp. and lagomorphs in the southern zone; and Lepus capensis and Ovis aries in the austral zone. The estimated density of L. griseus in Lago Peñuelas NR was 1.3 foxes/km2 .
Assuntos
Ração Animal/análise , Dieta/veterinária , Comportamento Alimentar/fisiologia , Raposas/fisiologia , Distribuição Animal , Animais , Chile , Ecossistema , FezesRESUMO
The suitability of Mazzaella laminarioides and Sarcothalia crispata as heavy metal biomonitors of Cd, Cu, Hg, Pb, and Zn was assessed by comparing bioaccumulation of these elements in different life stages and frond sizes in samples from three locations, San Vicente Bay (industrial area), Coliumo, and Quidico (the latter as a reference station), where different degrees of heavy metal pollution are recorded. Bioaccumulation and bioconcentration factors of Cd, Cu, Hg, Pb, and Zn were evaluated. The two macroalgae species showed similar patterns, with higher values of Cu, Hg, Pb, and Zn in polluted areas. M. laminarioides bioaccumulated higher concentrations of all metals assessed than S. crispata, independent of life stage and frond size. The results also showed significantly higher Cu, Hg, Pb, and Zn concentrations (p < 0.05) in water samples from San Vicente Bay than those measured in Coliumo and Quidico. Concentrations of Cd, Hg, Pb, and Zn in San Vicente Bay and Cd, Hg, and Pb in Coliumo and Quidico exceed the mean values considered to represent natural concentrations (Cu = 3.00 µg L-1; Zn = 5.00 µg L-1; Pb = 0.03 µg L-1; Cd = 0.05 µg L-1; Hg = 0.05 µg L-1); however, the concentrations recorded do not cause negative effects on the growth and survival of macroalgae. The assessment of heavy metals bioaccumulated in M. laminarioides and S. crispata, particularly Hg, Pb, and Zn, offers a reliable approach for pollution assessment in rocky intertidal environments. Cu and Cd concentrations in seawater samples from San Vicente and Coliumo Bays were significantly higher than in those from Quidico (p value < 0.05); no significant differences in Cd concentrations were observed between San Vicente and Coliumo Bays (p < 0.05). Exceptionally, Cd is bioaccumulated at high levels independent of its availability in the water, thus reaching high concentrations in control areas. High concentrations of metals like Cu and Zn may limit or inhibit Cd uptake in macroalgae, since the transport channels are saturated by some metals, reducing the accumulation of others. These macroalgae species offer good potential for the development of suitable heavy metal pollution survey tools in rocky intertidal environments.
Assuntos
Biomarcadores Ambientais , Monitoramento Ambiental/métodos , Metais Pesados/metabolismo , Rodófitas/fisiologia , Poluentes Químicos da Água/metabolismo , Baías , Chile , Mercúrio , Metais Pesados/análise , Água do Mar/química , Alga Marinha , Água , Poluentes Químicos da Água/análiseRESUMO
BACKGROUND: In Chile, three Hantavirus seropositive rodent species (O longicaudatus, A olivaceus and A longipilis) are distributed from the Pacific coast to the Andes mountains and represent nearly 90% of the rodents captured in the Xth Region. AIM: To study the seroprevalence of Hantavirus among captured rodent species and its relationship with the appearance of human cases of pulmonary syndrome. MATERIAL AND METHODS: From May 1998 to September 2001, 675 rodents were captured in the region. Serum samples were tested by ELISA for the presence of IgG antibodies against Andes and Sin Nombre virus. Sera from human cases with a suspected Hantavirus infection were analyzed for IgM antibodies against Black Lagoon virus and for IgG antibodies against Andes and Sin Nombre virus. RESULTS: Twenty two of the 675 rodents were seropositive for the virus, 18 O longicaudatus and 4 A longipilis. Regional seroprevalence changed from 2.2% in 1998, 0.0% in 1999, 1.0% in 2000 and up to 7.1% in 2001. A total of 77 positive human cases were studied from 1998 to March 2002. Although there were positive cases in all seasons, data showed a spring-summer seasonal preponderance. A relationship between the flowering of "colihue" bushes and the increased values of rodent abundance, seroprevalence and positive animals was established. CONCLUSIONS: A dispersal movement of O longicaudatus to open habitats close to human outdoor activities during the dry season was confirmed.
Assuntos
Reservatórios de Doenças , Síndrome Pulmonar por Hantavirus/veterinária , Orthohantavírus/fisiologia , Doenças dos Roedores/virologia , Animais , Anticorpos Antivirais/sangue , Chile/epidemiologia , Ecossistema , Ensaio de Imunoadsorção Enzimática , Orthohantavírus/classificação , Orthohantavírus/imunologia , Síndrome Pulmonar por Hantavirus/sangue , Síndrome Pulmonar por Hantavirus/epidemiologia , Humanos , Imunoglobulina G/sangue , Doenças dos Roedores/epidemiologia , Roedores , Estudos Soroepidemiológicos , População UrbanaRESUMO
In Chile, three Hantavirus seropositive rodent species (O longicaudatus, A olivaceus and A longipilis) are distributed from the Pacific coast to the Andes mountains and represent nearly 90 percent of the rodents captured in the Xth Region. Aim: To study the seroprevalence of Hantavirus among captured rodent species and its relationship with the appearance of human cases of pulmonary syndrome. Material and methods: From May 1998 to September 2001, 675 rodents were captured in the region. Serum samples were tested by ELISA for the presence of IgG antibodies against Andes and Sin Nombre virus. Sera from human cases with a suspected Hantavirus infection were analyzed for IgM antibodies against Black Lagoon virus and for IgG antibodies against Andes and Sin Nombre virus. Results: Twenty two of the 675 rodents were seropositive for the virus, 18 O longicaudatus and 4 A longipilis. Regional seroprevalence changed from 2.2 percent in 1998, 0.0 percent in 1999, 1.0 percent in 2000 and up to 7.1 percent in 2001. A total of 77 positive human cases were studied from 1998 to March 2002. Although there were positive cases in all seasons, data showed a spring-summer seasonal preponderance. A relationship between the flowering of "colihue" bushes and the increased values of rodent abundance, seroprevalence and positive animals was established. Conclusions: A dispersal movement of O longicaudatus to open habitats close to human outdoor activities during the dry season was confirmed