RESUMO

BACKGROUND: Mangrove forests provide many ecosystem services, including the provision of habitat that supports avian biodiversity. However, hurricanes can knock down trees, alter hydrologic connectivity, and affect avian habitat. In 1995, Hurricanes Opal and Roxanne destroyed approximately 1,700 ha of mangrove forest in Laguna de Términos, Mexico. Since then, hydrological restoration has been implemented to protect the mangrove forest and its biodiversity. METHODS: Since avian communities are often considered biological indicators of ecosystem quality, avian diversity and species relative abundance were evaluated as indicators of mangrove restoration success by comparing undisturbed mangrove patches with those affected by the hurricanes. Using bird surveys, similarity analyses, and generalized linear models, we evaluated the effects of water quality variables and forest structure on the relative abundance and diversity of the avian community in disturbed, restored, and undisturbed mangrove patches. RESULTS: Higher bird species richness and relative abundances were found in disturbed and restored sites compared to the undisturbed site. After restoration, values of frequency of flooding, water temperature, tree density, and the number of tree species were more similar to that of the undisturbed site than to the values of the disturbed one. Such variables influenced the relative abundance of bird guilds in the different habitat conditions. Furthermore, some insectivorous bird species, such as the Yellow Warbler and Tropical Kingbird, were found to be similarly abundant in both undisturbed and restored sites, but absent or very low in occurrence at the disturbed site. CONCLUSIONS: Collectively, our results strongly suggest that hydrologic restoration helps to enhance niche availability for different bird guilds, including water and canopy bird species. Our work can help inform management strategies that benefit avian communities in mangrove forests and wetland systems.

RESUMO

The aim of the present study was to test whether different degrees of human activity affect the diet of the Brazilian silverside Atherinella brasiliensis in two tropical estuaries. Fish were collected along the salinity gradient of two Brazilian estuaries, the heavily impacted Paraiba Estuary and the less impacted Mamanguape Estuary, in the dry and wet seasons. The findings confirm that A. brasiliensis has generalist feeding habits and is able to change its diet under different environmental conditions. The results indicate clear spatial (i.e. along the estuarine gradient) changes in diet composition in both estuaries, but diet was also influenced by the degree of anthropogenic disturbance. During the wet season in the nutrient enriched Paraiba Estuary, when human activity was higher, the diet of A. brasiliensis was poorer and dominated by few dietary items, reflecting the potential impoverishment of prey items in this heavily disturbed system. The specimens collected in the most affected estuary also had a greater frequency of micro-plastics and parasites in their stomachs, reflecting the greater degree of human disturbance in the estuary. The present findings suggest that the diet of A. brasiliensis could be a useful indicator of changes in the ecological quality of these and other tropical estuaries of the western Atlantic Ocean.

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RESUMO

This study shows, in a multiple-level approach, the responses of Salvinia auriculata to Cd pollution in aquatic ecosystems. S. auriculata ramets were cultivated in nutrient solution and subjected to five treatments with Cd for ten days. At the end of the experiment, the number of new ramets and the dry biomass were determined. For ultrastructural observations, the leaves of S. auriculata were analyzed using a scanning electron microscope and transmission electron microscope. At the end of the experiment, the plants exposed to Cd showed damage in the leaves including necrosis and chlorosis, stomate deformations and damaged trichomes. We observed a decrease in the number of new ramets and dry biomass of S. auriculata following the increase in Cd concentration in the solution. At the ultrastructural level, leaves exposed to Cd presented chloroplast deformations and deterioration in the cell wall. All the symptoms of toxicity were directly proportionate to the concentration of Cd in the solution. The results suggests that S. auriculata shows good potential for use as a bioindicator and it can be used in the biomonitoring of aquatic ecosystems contaminated by Cd.

Este estudo apresenta, em diferentes níveis de abordagem, a resposta de Salvinia auriculata à poluição de ecossistemas aquáticos por cádmio (Cd). Rametes de S. auriculata foram cultivados em solução nutritiva e expostos a cinco tratamentos com Cd durante dez dias. Ao final do experimento, o número de novos rametes e a biomassa seca foram determinados. Para observações ultraestruturais, as folhas de S. auriculata foram analisadas utilizando-se um microscópio eletrônico de varredura e a microscopia eletrônica de transmissão. Ao final do experimento, as plantas expostas ao Cd apresentaram danos nas folhas, como necrose e clorose, além de estômatos deformados e tricomas danificados. Foi observado um menor número de rametes e diminuição da biomassa seca de S. auriculata com o aumento da concentração de Cd na solução. Em nível ultraestrutural, as folhas expostas ao Cd apresentaram má formação dos cloroplastos e deterioração da parede celular. Todos os sintomas de toxidade foram diretamente proporcionais à concentração de Cd na solução. Os resultados sugerem que S. auriculata apresenta um bom potencial para uso como bioindicador e pode ser usada em programas de biomonitoramento de ecossistemas aquáticos contaminados por Cd.

Assuntos

RESUMO

This study shows, in a multiple-level approach, the responses of Salvinia auriculata to Cd pollution in aquatic ecosystems. S. auriculata ramets were cultivated in nutrient solution and subjected to five treatments with Cd for ten days. At the end of the experiment, the number of new ramets and the dry biomass were determined. For ultrastructural observations, the leaves of S. auriculata were analyzed using a scanning electron microscope and transmission electron microscope. At the end of the experiment, the plants exposed to Cd showed damage in the leaves including necrosis and chlorosis, stomate deformations and damaged trichomes. We observed a decrease in the number of new ramets and dry biomass of S. auriculata following the increase in Cd concentration in the solution. At the ultrastructural level, leaves exposed to Cd presented chloroplast deformations and deterioration in the cell wall. All the symptoms of toxicity were directly proportionate to the concentration of Cd in the solution. The results suggests that S. auriculata shows good potential for use as a bioindicator and it can be used in the biomonitoring of aquatic ecosystems contaminated by Cd.

Este estudo apresenta, em diferentes níveis de abordagem, a resposta de Salvinia auriculata à poluição de ecossistemas aquáticos por cádmio (Cd). Rametes de S. auriculata foram cultivados em solução nutritiva e expostos a cinco tratamentos com Cd durante dez dias. Ao final do experimento, o número de novos rametes e a biomassa seca foram determinados. Para observações ultraestruturais, as folhas de S. auriculata foram analisadas utilizando-se um microscópio eletrônico de varredura e a microscopia eletrônica de transmissão. Ao final do experimento, as plantas expostas ao Cd apresentaram danos nas folhas, como necrose e clorose, além de estômatos deformados e tricomas danificados. Foi observado um menor número de rametes e diminuição da biomassa seca de S. auriculata com o aumento da concentração de Cd na solução. Em nível ultraestrutural, as folhas expostas ao Cd apresentaram má formação dos cloroplastos e deterioração da parede celular. Todos os sintomas de toxidade foram diretamente proporcionais à concentração de Cd na solução. Os resultados sugerem que S. auriculata apresenta um bom potencial para uso como bioindicador e pode ser usada em programas de biomonitoramento de ecossistemas aquáticos contaminados por Cd.

RESUMO

The study was conducted at the Mata dos Godoy State Park in Londrina, state of Paraná, Brazil. Baited pitfall traps were installed in the forest, in adjacent abandoned pasture land, and on the borders between these two environments. Every two weeks, from June 1999 to May 2000, the traps were placed for 24 hours and the material was collected every 12 hours. The 4687 specimens of Scarabaeinae collected belong to 13 genera and 27 species. The most frequent species were Onthophagus catharinensis (Paulian, 1936) (22.1%), Onthophagus hirculus (Mannerhein, 1829) (20.1%), Dichotomius mormon (Ljungh, 1799) (13.1%), Sulcophanaeus menelas (Laporte, 1840) (12.8%), and Eurystemus parallelus (Dalman, 1824) (10.6%). The other species collected amounted to less than 4.7%. The difference in numbers of specimens collected in the three environments was not significant (K(2.72) = 0.63, p = 0.729). The distribution patterns of species composition for the different environments (ANOSIM R = 0.29, p 0.01) and activity periods (ANOSIM R = 0.18, p 0.01) were different. Sulcophanaeus menelas, Canthidium aff. trinodosum, O. hirculus, and E. parallelus were the most abundant species, being predominantly diurnal; the first three species were more active on abandoned pasture. Most of the Dichothomius assifer (Eschscholtz, 1822) and D. mormon specimens were captured at night. The latter species was the most abundant in edges, whereas D. assifer, Scybalochantum aff. zischkai, and O. catharinensis can be considered bioindicators because they were either exclusively or highly predominant in the best preserved areas. A larger number of individuals was observed from December 1999 through March 2000, which is the time of the year when adults of Scarabaeinae normally emerge and fly, in the studied region. The highest diversity (88.89%) was observed in February.

RESUMO

The study was conducted at the Mata dos Godoy State Park in Londrina, state of Paraná, Brazil. Baited pitfall traps were installed in the forest, in adjacent abandoned pasture land, and on the borders between these two environments. Every two weeks, from June 1999 to May 2000, the traps were placed for 24 hours and the material was collected every 12 hours. The 4687 specimens of Scarabaeinae collected belong to 13 genera and 27 species. The most frequent species were Onthophagus catharinensis (Paulian, 1936) (22.1%), Onthophagus hirculus (Mannerhein, 1829) (20.1%), Dichotomius mormon (Ljungh, 1799) (13.1%), Sulcophanaeus menelas (Laporte, 1840) (12.8%), and Eurystemus parallelus (Dalman, 1824) (10.6%). The other species collected amounted to less than 4.7%. The difference in numbers of specimens collected in the three environments was not significant (K(2.72) = 0.63, p = 0.729). The distribution patterns of species composition for the different environments (ANOSIM R = 0.29, p 0.01) and activity periods (ANOSIM R = 0.18, p 0.01) were different. Sulcophanaeus menelas, Canthidium aff. trinodosum, O. hirculus, and E. parallelus were the most abundant species, being predominantly diurnal; the first three species were more active on abandoned pasture. Most of the Dichothomius assifer (Eschscholtz, 1822) and D. mormon specimens were captured at night. The latter species was the most abundant in edges, whereas D. assifer, Scybalochantum aff. zischkai, and O. catharinensis can be considered bioindicators because they were either exclusively or highly predominant in the best preserved areas. A larger number of individuals was observed from December 1999 through March 2000, which is the time of the year when adults of Scarabaeinae normally emerge and fly, in the studied region. The highest diversity (88.89%) was observed in February.

RESUMO

The study was conducted at the Mata dos Godoy State Park in Londrina, state of Paraná, Brazil. Baited pitfall traps were installed in the forest, in adjacent abandoned pasture land, and on the borders between these two environments. Every two weeks, from June 1999 to May 2000, the traps were placed for 24 hours and the material was collected every 12 hours. The 4687 specimens of Scarabaeinae collected belong to 13 genera and 27 species. The most frequent species were Onthophagus catharinensis (Paulian, 1936) (22.1%), Onthophagus hirculus (Mannerhein, 1829) (20.1%), Dichotomius mormon (Ljungh, 1799) (13.1%), Sulcophanaeus menelas (Laporte, 1840) (12.8%), and Eurystemus parallelus (Dalman, 1824) (10.6%). The other species collected amounted to less than 4.7%. The difference in numbers of specimens collected in the three environments was not significant (K(2.72) = 0.63, p = 0.729). The distribution patterns of species composition for the different environments (ANOSIM R = 0.29, p 0.01) and activity periods (ANOSIM R = 0.18, p 0.01) were different. Sulcophanaeus menelas, Canthidium aff. trinodosum, O. hirculus, and E. parallelus were the most abundant species, being predominantly diurnal; the first three species were more active on abandoned pasture. Most of the Dichothomius assifer (Eschscholtz, 1822) and D. mormon specimens were captured at night. The latter species was the most abundant in edges, whereas D. assifer, Scybalochantum aff. zischkai, and O. catharinensis can be considered bioindicators because they were either exclusively or highly predominant in the best preserved areas. A larger number of individuals was observed from December 1999 through March 2000, which is the time of the year when adults of Scarabaeinae normally emerge and fly, in the studied region. The highest diversity (88.89%) was observed in February.

RESUMO

The use of arthropods for monitoring habitat changes has grown widely in the last decades. In Brazil, however, most of the studies in restored areas have involved only vegetation changes. The present study aimed at investigating recolonization patterns of epigeic arthropods in recently restored sites of semideciduous forests in southeastern Brazil. We compared the community structure of adjoining sites 5, 17, 29 and 36 months old with that at a nearby forest remnant (reference site). We also determined the most abundant species and looked for ecological indicator species of each site age. Arthropods were sampled using pitfall traps, and their assemblages were described and compared with multi- and univariate statistical methods. Species abundance and richness equivalent to the reference site were reached at five months after planting, however species composition was very distinctive not only in relation to the reference site, but also among restored sites. Some of the main species found in this restoration stage are common in agroecosystems or cerrado vegetation. Nevertheless, there was a clear trend of arthropod fauna in restored sites moving toward the fauna in the forest remnant over time. Our results also highlighted ants and termites because of their abundance and ants because of their high value as ecological indicators of restoration age.

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