Ioni Gonçalves Colares

Feeding habits of capybaras (Hydrochoerus hydrochaeris, Linnaeus 1766), in the Ecological Reserve of Taim (ESEC - Taim) - south of Brazil

The aim of this study was to determine feeding habitats of capybaras in the ESEC-Taim (RS, Brazil), using microhistological analyses of feces. Data were analyzed seasonally. In 172 samples analyzed, 17 species were identified, with predominance of Poaceae. Zizaniopsis bonariensis was the most frequent species in winter (38%), spring (32%) and summer (26.5%) and Paspalum disthichum in fall (31.5%). A observed increase in vegetation consumption during summer might be due to the food quality. Capybaras showed an opportunistic behavior in the winter and summer and a more selective behavior in spring and fall. Capybaras from the ESEC-Taim varied diet according to the season and alimentary availability.

Using a toxicity test with Ruppia maritima (Linnaeus) to assess the effects of Roundup.

Glyphosate, the active ingredient in Monsantos broad-spectrum herbicide Roundup, consists of one of the most used pesticides worldwide, but its effects on the marine flora are still not well understood. Were examined Roundup toxic effects on Ruppia maritima specimens collected from Jansen Lagoon (São Luís, MA, Brazil) and acclimatized under laboratory conditions. The numbers of new and dead leaves, the root and leaf length, the chlorophyll a content, and the weight of R. maritima branches were determined before and after exposure to different Roundup concentrations for seven days. High concentrations caused a significant lethal effect. In addition, significant changes were observed in the wet and dry weights, the number and length of the leaves, and the chlorophyll a content. Leaf elongation was observed in the branches exposed to low concentrations, and this change was likely activated as a compensatory mechanism. The results indicate that high concentrations of this herbicide may compromise estuarine flora.

Composição florística e fitossociologia de macrófitas aquáticas em um banhado continental em Rio Grande, RS, Brasil

This work aimed to study the floristics and phytosociology of aquatic macrophytes in a continental wetland. A total of, 100 plots, (1 m2) were distributed systematically (intervals of 1 m), in 10 transects (20 m), in the Banhado 25 area (31°59’33”S; 52°17’32”O). Monthly collection data over a one-year period included observing plants “in loco”, collecting, identifying and classifying the plants according to habit and life form. For each species recorded we calculated absolute and relative frequency and coverage and importance value index (IVI). We analyzed the floristic similarity (Sorensen’s index) and applied linear regression. The survey yielded 82 species of vascular aquatic macrophytes, belonging to 33 families. In species richness, Cyperaceae (16 taxa), followed by Poaceae and Asteraceae (12 taxa each), showed greater contribution. The herbaceous habit (88%) and amphibious life form (94%) were the most representative. Scirpus giganteus Kunth had the highest IVI (27.58%). Higher coverage rates of this species showed a significant decrease in species richness (r2 = 0.503; p < 0.0001). The change in floristic composition between margin and interior of the wetland was evidenced by similarity analysis, forming two groups, possibly separated by humidity.

PREFERÊNCIA ALIMENTAR DO PEIXE-BOI DA AMAZÔNIA EM CATIVEIRO

Estudos sobre alimentacao de uma especie em perigo de extincao contribuem para o conhecimento mais complexo sobre sua ecologia, bem como sua preservacao e/ou manejo. Dessa maneira, visando obter um melhor desenvolvimento e melhor oferta de alimentos aos animais mantidos em cativeiro no Instituto Nacional de Pesquisa da Amazonia foi realizado um experimento para determinar suas preferencias alimentares. Para a observacao do comportamento alimentar do peixe-boi da Amazonia foram utilizados oito animais, sendo estes mantidos em uma piscina com 28,26 m2 de area e 1,0 m de profundidade. Cada animal foi identificado com fitas coloridas e pesado no inicio e no final do experimento. Foram oferecidas, simultaneamente, 11 especies de macrofitas aquaticas por dia, em quantidades iguais. Entre os itens ofertados, os animais demonstraram maior interesse pelas plantas emergentes (57,4% do tempo), tais como as gramineas Paspalum repens e Oryza grandiglumis, sendo encontradas diferencas na escolha das macrofitas em virtude da faixa etaria. Constatou-se ainda, que os peixes-bois amazonicos, ao alimentarem-se de plantas com incrustacoes de microorganismos estejam obtendo em sua dieta uma suplementacao de calcio, cujos teores, para as plantas da Amazonia Central, sao extremamente baixos.

Parâmetros Bioquímicos do Sangue do Peixe-boi da Amazônia (Trichechus inunguis, Mammalia: Sirenia)

Os parâmetros hematologicos e bioquimicos do sangue possibilitam obter informacoes sobre a situacao fisiologica dos animais ou de sua populacao, permitindo desta forma o diagnostico de eventuais patologias. O objetivo deste trabalho foi determinar os valores normais de alguns parâmetros bioquimicos do sangue do peixe-boi da Amazonia em cativeiro e compara-lo com outros animais. Neste estudo foram utilizados 10 peixes-bois amazonicos mantidos em cativeiro no Instituto Nacional de Pesquisas da Amazonia, sendo estes alimentados com capim angola. A coleta de sangue foi realizada no periodo da manha, 24 horas apos os animais terem sido alimentados, sendo as amostras centrifugadas, extraido o plasma e soro, e posteriormente armazenados a - 15° C. As analises bioquimicas foram realizadas num periodo maximo de 10 dias apos a coleta, onde foram utilizados os Kits LABTEST para determinar as concentracoes de glicose enzimatica, lipides totais, ureia, proteinas totais e albumina. As globulinas foram determinadas pela subtracao da concentracao de albumina da concentracao de proteinas totais. O fracionamento de proteinas foi feito pelo metodo de eletroforese, com tampao barbital, em suporte de acetato de celulose. Entre os parâmetros analisados foram encontrados as medias de 43,3 mg/dl glicose; 543,6 mg/dl lipides; 29,3 mg/dl ureia; 6,3 g/dl proteinas; 3,5 g/dl albumina; 2,8 g/dl globulina. Alguns parâmetros foram semelhantes aos valores obtidos em peixes-bois marinhos. A vida sedentaria e/ou alimentacao inadequada podem ter tido influencia nos resultados encontrados neste estudo.

Biochemical parameters of the amazonian manatee´s blood (Trichechus inunguis, Mammalia: Sirenia)

The blood biochemical and hematological parameters make possible to acquire information about the physiological situation of animals or their population, permitting in this way the diagnosis of possible pathologies. The objective of this work was to check the normal values of some biochemical parameters of the captive Amazonian manatee´s blood and compare them with other animals´. In this study, 10 Amazonian manatees kept in captivity in the Instituto Nacional de Pesquisas da Amazonia, being fed with Angola herb. The blood collection was made in the morning, 24 hours after the animals´ feeding, the samples were centrifuged and had serum and plasma extracted therefore stored under -15o C. The biochemical analyses were made in a maximum period of 10 days after the collection, where LABTEST kits were applied to determine the concentrations of enzymatic glucose, total lipids, urea, total proteins and albumin. The globulins were checked by the subtraction of the albumin concentration from the total proteins concentration. The fractionation of the proteins was done by electrophoresis method, with barbital tampon, over one support made of cellulose acetate. Amongst the analyzed parameters were found the following averages: 43,3 mg/dl glucose; 543,6 mg/dl lipids; 29,3 mg/dl urea; 6,3 g/dl proteins; 3,5 g/dl albumin; 2,8 g/dl globulin. Some of them presented values similar to the obtained ones in marine manatees. Sedentary lifestyle and inadequate diet may have influenced results found in this study.

The partitioning of food resources between two rodents in the subtropical region of southern Brazil

The capybara (Hydrochoerus hydrochaeris) and nutria (Myocastor coypus) are herbivorous semi-aquatic rodents. Although these rodents occur in sympatry in southern South America, little is known about how the two species interact in relationship to food resources. In this context, the aim of this study was to analyze the food resource overlap, the feeding strategy and the diversity of the diet of capybaras and nutria. A micro-histological analysis of feces was used to study the diets. A total of 48 plant species belonging to 10 families were identified in the diet of H. hydrochaeris, and a total of 49 species belonging to 14 families were identified in the diet of M. coypus. According to the Amundsen graphical method, both rodents adopted a specialized strategy for feeding on Poaceae and a generalized strategy for other families. The results of a multivariate analysis of the dietary data showed significant differences between the two rodent species and among the seasons. These differences between diets may be related to the different proportions of each food item eaten. However, the dietary overlap between the two rodents in the Taim wetland was high, suggesting that partitioning of other resources ensured the coexistence of the species.

Food preference of the amazonian manatee in captivity

Studies on one endangered species´ feeding contribute to the more complex knowledge about its ecology, as also its preservation and/or management. By this means, aiming to obtain one better development and food supply for the animals kept in captivity in the Instituto Nacional de Pesquisa da Amazonia, one experiment was conducted to verify their food preferences. Aiming to observe the Amazonian manatee´s feeding behavior, eight animals were used kept inside one pool with 28,26 m2 and 1,0 m deep. Each animal was identified with colored ribbons and weighed at the beginning and at the end of the experiment. Simultaneously, equal quantities of 11 species of aquatic macrophytes were daily provided. Among the provided items, the animals showed more interest for the emerging plants (57,4% of the time), like the grasses Paspalum repens e Oryza grandiglumis, where differences on choosing the macrophytes due to the age bracket were detected. It was also known that the Amazonian manatees, when fed with plants presenting inlays of microorganisms are getting in your diet a calcium supplementation which content, comparing with the plants of the Central Amazon, are extremely low.