Does a small forested area contribute to enhance species richness and diversity of fish assemblage at an urban stream? / Uma pequena área florestada contribui para aumentar a riqueza de espécies e diversidade da assembleia de peixes de um riacho urbano?

Conservation Units (CU) aim to contribute to the balance between human and environmental demand, by protecting natural resources and biological communities. In this study we examined the differences in the attributes of the fish community in four stretches of an urban stream, two inside and two outside the CU, without vegetation cover, and tested the hypothesis that the presence of riparian vegetation is positively reflected in the attributes of fish fauna. Five species were caught, distributed into four orders and five families. Attributes like richness, abundance, dominance, Shannon-Wiener diversity, and evenness were estimated and significant differences were detected for continuous stretches considering stream flow direction. The first stretches (URBI and UCI) presented a lower diversity that increased gradually until the last stretch, and an inverse result was found for dominance. These changes occurred regardless the location of the stretch, in- or outside the CU. The importance of Conservation Units within urban areas is severely affected by the lack of continuity of forested areas, especially riparian vegetation. Therefore, we suggest the effective recovery of permanent preservation areas and of riparian vegetation in order to mitigate the impacts of human activities.

Unidades de Conservação (UC) contribuem para o equilíbrio entre demanda humana e ambiental, protegendo recursos naturais e as comunidades biológicas. Neste contexto, o presente estudo investigou a existência de diferenças nos atributos da comunidade Ictiíca em quatro trechos de um riacho urbano, dois localizados no interior de uma UC e dois externos a ela, sem cobertura vegetal, testando a hipótese de que áreas vegetadas aumentam a diversidade e riqueza de espécies e diminuem a dominância em assembleias de peixes. Foram capturadas cinco espécies, distribuídas em quatro ordens e cinco famílias. Atributos como riqueza, abundância, dominância, diversidade de Shannon-Wiener e equitabilidade foram calculados e diferenças estatísticas encontradas para trechos contínuos considerando o fluxo do riacho. Os primeiros trechos (URBI e UCI) apresentaram menor diversidade, que foi gradualmente aumentando até o último trecho. Resultado inverso observado para a dominância. Estas mudanças ocorreram independentemente da localização do trecho, interno ou externo à UC. Concluiu-se que a efetividade de Unidades de Conservação em áreas urbanas é seriamente prejudicada quando da ausência de continuidade de áreas florestadas, em especial da vegetação ciliar. Sugere-se, portanto, a efetiva restauração das áreas de preservação permanente e da vegetação ciliar a fim de minimizar os impactos da ação antrópica.

Low-Intensity swimming training after weaning improves glucose and lipid homeostasis in MSG hypothalamic obese mice.

Low-intensity swimming training, started at an early age, was undertaken to observe glycemic control in hypothalamic obese mice produced by neonatal monosodium l-glutamate (MSG) treatment. Although swimming exercises by weaning pups inhibited hypothalamic obesity onset and recovered sympathoadrenal axis activity, this event was not observed when exercise training is applied to young adult mice. However, the mechanisms producing this improved metabolism are still not fully understood. Current work verifies whether, besides reducing fat tissue accumulation, low-intensity swimming in MSG-weaned mice also improves glycemic control. Although MSG and control mice swam for 15 min/day, 3 days a week, from the weaning stage up to 90 days old, sedentary MSG and normal mice did not exercise at all. After 14 h of fasting, animals were killed at 90 days of age. Retroperitonial fat accumulation was measured to estimate obesity. Fasting blood glucose and insulin concentrations were also measured. Mice were also submitted to ipGTT. MSG obese mice showed fasting hyperglycemia, hyperinsulinemia, and glucose intolerance and insulin resistance. However, the exercise was able to block MSG treatment effects. Higher total cholesterol and triglycerides observed in MSG mice were normalized by exercise after weaning. Exercised MSG animals had higher HDLc than the sedentary group. Data suggest that early exercise training maintains normoglycemia, insulin tissue sensitivity, and normal lipid profile in mice programmed to develop metabolic syndrome.