The metacommunity framework has greatly advanced our understanding about the importance of local and regional processes structuring ecological communities. However, information on how metacommunity structure and the relative strengths of their underlying mechanisms change through time is largely lacking. Dynamic systems that undergo environmental temporal changes and disturbances, such as floodplains, serve as natural laboratories to explore how their metacommunity structure change in time. Here we applied the Elements of Metacommunity Structure framework and variation partitioning analysis to assess how temporal changes in the local environmental factors and regional dispersal processes in the rain season influence a seasonal floodplain‐fish metacommunity. Across four months, relevant environmental factors were measured across 21 patches where over 3500 individual fish were sampled. Connectivity was measured using landscape resistance‐based metrics and additional spatial variation in metacommunity structure was assessed via spatial autocorrelation functions. The metacommunity structure changed from nestedness, at the beginning of the flood season, to a quasi‐Clementsian gradient at the end. Our analyses show that connectivity is only important in the beginning of the flood season whereas environment is only important at the end. These results suggest that this metacommunity is structured by changes between dispersal limitation and environmental filtering through time.

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Building bridges between environmental and political agendas is essential nowadays in face of the increasing human pressure on natural environments, including wetlands. Wetlands provide critical ecosystem services for humanity and can generate a considerable direct or indirect income to the local communities. To meet many of the sustainable development goals, we need to move our trajectory from the current environmental destructive development to a wiser wetland use. The current article contain a proposed agenda for the Pantanal aiming the improvement of public policy for conservation in the Pantanal, one of the largest, most diverse, and continuous inland wetland in the world. We suggest and discuss a list of 11 essential interfaces between science, policy, and development in region linked to the proposed agenda. We believe that a functional science network can booster the collaborative capability to generate creative ideas and solutions to address the big challenges faced by the Pantanal wetland.

Clove oil is used as a fish anesthetic because it is a natural and inexpensive product with low toxicity risks. The goal of the present study was to determine the appropriate concentration of clove oil for small-sized tropical fish to be used in mark-recapture studies or when individuals are to be sacrificed. We applied three different clove oil concentrations (D1=0.05 mL, D2=0.10 mL and D3=0.20 mL per 500 mL of water) on three small-sized fish species. We found a negative relationship between induction time and treatment for two species (Hyphessobrycon sp.1 and Hemigrammus sp.), while concentration was unrelated to recovery time. Fish body length was positively related to induction time in the D2 treatment for Hemigrammus sp., and negatively for Hyphessobrycon sp.1 in the D1 treatment, but was unrelated to recovery time for three species and treatments. Mortality rates varied across treatments, but higher rates were observed with higher clove oil concentrations. We conclude that 0.05 mL of clove oil per 500 mL of water is the most efficient dose for studies where fish will be released back to their natural habitats, while 0.20 mL of clove oil is recommended for studies that require fish euthanization for further laboratory analyses.Keywords: Eugenol, anesthesia, euthanasia, field experiment, fish manipulation.A eficiência do óleo de cravo como anestésico e em procedimentos de eutanaisa em peixes de pequeno porte Resumo O óleo de cravo é recomendado como anestésico para peixes por ser produto de origem natural, baixo custo e apresentar poucos riscos de intoxicação. O objetivo deste trabalho foi determinar concentrações adequadas de óleo de cravo para anestesiar ou eutanasiar peixes de pequeno porte em ambiente natural. Foram testadas três concentrações do anestésico (D1=0,05 mL, D2=0,10 mL e D3=0,20 mL) em três espécies de peixes de pequeno. Houve uma relação negativa entre o tempo para a sedação dos indivíduos e a concentração para duas espécies (Hyphessobrycon sp.1 e Hemigrammus sp.), porém não foi encontrada relação entre o tempo para recuperação e as concentrações. Os exemplares maiores de Hemigrammus sp. levaram mais tempo para serem sedados no tratamento D2, já o contrário foi observado para Hyphessobrycon sp.1 no tratamento D1, enquanto que não houve efeito do comprimento no tempo de recuperação das três espécies. A mortalidade dos indivíduos variou entre as três concentrações do anestésico e as maiores taxas de mortalidade ocorreram nas maiores concentrações. Desse modo, a concentração de 0,05 mL é eficiente para estudos que envolvem manuseio e a soltura dos peixes, enquanto que a concentração de 0,20 mL é recomendada em estudos onde os peixes precisam ser sacrificados.Palavras-chave: Eugenol, anestesia, eutanásia, experimento de campo, manipulação de peixes.

Abstract:This study aimed to evaluate the spatial and temporal variation of the feeding guilds of fish communities of 10 oxbow lakes of the Cuiabá River in the Pantanal. The lagoons were sampled in three periods of the hydrological cycle (beginning and ending of the dry and flooding season of 2005). The feeding guilds were determined through analysis of stomach contents of the most abundant species in the community. Were analyzed 37 species belonging to eight trophic guilds (insectivore, herbivore, omnivore, zooplanktivore, planktivore, detritivore, benthivore and iliophage), whitch varied spatially and temporally. A change in the composition of trophic guilds between the periods and locations was observed, but the number of guilds did not vary for either of them. Our results suggest that spatial and temporal variation in the composition of the guilds can be related to many factors, such as alterations in the composition of the community where new species can contribute to the different trophic guilds; and the exploration of more abundant resources in certain periods of the year favoring the presence of some guilds only in some periods. Keywords: trophic groups, fishes, hydrological cycle, feeding ecology, community structure. Resumo: O presente trabalho teve como objetivo avaliar a variação espacial e temporal das guildas alimentares das comunidades de peixes em 10 lagoas marginais do Rio Cuiabá no Pantanal. As lagoas foram amostradas em três períodos do ciclo hidrológico (início e final da seca e início da enchente de 2005). As guildas alimentares foram determinadas através da análise do conteúdo estomacal das espécies mais abundantes da comunidade. Foram analisadas 37 espécies pertencentes a oito guildas alimentares (insetívora, herbívora, onívora, zooplanctívora, planctívora, detritívora, bentívora e iliófaga), as quais variaram espacial e temporalmente. Observamos uma mudança na composição das guildas tróficas entre os períodos e locais analisados, porém o número de guildas não variou espaço-temporalmente. Nossos resultados sugerem que as mudanças espaciais e temporais na composição das guildas podem estar relacionadas com diversos fatores, como as alterações na composição da comunidade onde novas espécies podem compor as diferentes guildas; a exploração de recursos mais abundantes em determinadas épocas do ano favorecendo a presença de algumas guildas somente em alguns períodos. Palavras-chave: grupos tróficos, peixes, ciclo hidrológico, ecologia alimentar, estrutura de comunidade.

The rio Cuiabá is one of the most important tributaries of the upper rio Paraguay basin that form the Pantanal wetlands. The fishing resources of the rio Cuiabá basin were studied based on landing data obtained from the Fish Market of the city of Cuiabá, State of Mato grosso, Brazil. A description is given of the composition and origin of the 2000 and 2001 catch. The rio Cuiabá is the main source of fish for Cuiabá, although some fish sold locally comes from the rio Paraguay. The 2000-2001 catch consisted mainly of migratory species. The main landed species were the pimelodids pintado -Pseudoplatystoma corruscans, cachara -Pseudoplatystoma fasciatum, and jaú -Paulicea luetkeni, and the characiforms pacu -Piaractus mesopotamicus, piraputanga -Brycon microlepis, piavuçu -Leporinus macrocephalus, and dourado -Salminus brasiliensis. Large catfishes (Pimelodidae) represented 70% of the landed fish, among which pintado was the most abundant. The data indicate that current catches are smaller than those recorded in the early 1980s and fish are caught far off the urban zone. Moreover, although the number and composition of species caught were similar to those of the 80s, the distribution of species abundance has changed. Currently, fisheries catch more carnivorous species than fish from lower trophic levels. These findings cannot be credited solely to overfishing, but appear to result from a complex interaction of factors, i.e., environmental degradation, changes in market preferences, and restrictive legal fishing regulations.O recurso pesqueiro da bacia do rio Cuiabá, um dos mais importantes tributários da bacia do Alto Paraguai, formadora do Pantanal, foi estudado a partir dos dados de desembarque de pescado obtidos no Mercado do Porto de Cuiabá, Mato Grosso, Brasil. São descritas a composição e procedência das capturas para os anos de 2000 e 2001. O rio Cuiabá é a fonte dominante de pescado para a cidade de Cuiabá, mas uma parte do pescado comercializado localmente é oriunda do rio Paraguai. Além disso, atualmente o pescado vem de regiões mais distantes da zona urbana. Constatou-se que a pesca incide basicamente sobre espécies migradoras. As principais espécies capturadas foram os pimelodídeos pintado -Pseudoplatystoma corruscans, cachara -Pseudoplatystoma fasciatum e jaú -Paulicea luetkeni e os caraciformes pacu -Piaractus mesopotamicus, piraputanga -Brycon microlepis, piavuçu -Leporinus macrocephalus e dourado -Salminus brasiliensis. Os grandes bagres (Pimelodidae) foram os responsáveis por 70% do pescado desembarcado no período de estudo, dentre os quais o pintado foi a espécie mais capturada. Os dados indicam que as capturas atuais estão bem aquém daquelas registradas no início da década de 80. Além disso, apesar do número e composição de espécies capturadas serem similares àqueles da década de 80, a distribuição da abundância mudou. Atualmente a pesca captura mais espécies carnívoras do que espécies de níveis tróficos inferiores. Estes achados não podem ser creditados somente a sobrepesca, mas parecem resultar ...

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Ferraz et al. (2008) indicated the need for planning in biological monitoring in the Amazon, and reviewed what they considered recent progress. The problems and solutions they discuss are well known, and it is unlikely that many biologists would disagree with most of them. However, the authors do not indicate that most of these issues are already being addressed in practice in the Amazon, especially by the Programa de Pesquisas em Biodiversidade (PPBio) of the Brazilian Ministry of Science and Technology. The only major issue about which we do not agree with Ferraz et al. (2008) relates to the design of monitoring programs. The authors recommended tailoring experimental designs to specific threats, which will result in a multitude of idiosyncratic designs and incompatible data sets. We suggest that generic broad‐scale designs will allow us to answer more questions with greater confidence, because the investment in each location provides information about regional and global questions. Although specific designs may be more effective in some cases, there are insufficient resources available to install different research infrastructure for every possible threat.