DECOL - Departamento de Ecologia

URI Permanente desta comunidadehttps://repositorio.ufrn.br/handle/123456789/26657

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Mixed food web control and stability in a Cerrado river (Brazil)
(Pan-American Journal of Aquatic Sciences, 2010) Angelini, Ronaldo; Aloisio, Gustavo Ribeiro; Carvalho, Adriana Rosa
O entendimento dos mecanismos que regulam a dinâmica das teias tróficas aquáticas tem sido um importante tópico desde que a pesquisa ecológica passou a enfatizar a estrutura dos ecossistemas. O objetivo deste estudo foi verificar se a composição das espécies de peixes era a mesma em três diferentes habitats num trecho do Rio Corrente (GO), e se fossem as mesmas, isto permitiria avaliar a teia trófica num único modelo, pois do contrário, seriam necessários um modelo para cada habitat. O modelo Ecopath e o índice de ranking de espécies-chave foram usados para avaliar a teia trófica e entender os mecanismos de controle do sistema. Cinco amostragens no período de junho de 2003 até junho de 2005 foram realizadas em três diferentes habitats ao longo do Rio Corrente. Os resultados mostraram que: i) há apenas sete espécies de peixes; ii) há alta similaridade entre os habitats; iii)todas as espécies se reproduziram na estação chuvosa, com exceção de Brycon nattereri. Um modelo Ecopath indicou que o sistema tem baixa resiliência e estabilidade. O ranking de espécies chave mostrou que o controle do sistema é misto, com um predador, Salminus hilarii, ou consumidor intermediário, Astyanax altiparanae e um consumidor de nível trófico dois (invertebrados terrestres) apresentando, respectivamente os maiores valores de índices de espéciechave
Bird communities in different phytophysiognomies of the cerrado biome
(Taylor and Francis, 2012-03-05) Laranjeiras, Thiago Orsi; Moura, Nárgila Gomes de; Vieira, Ludgero Cardoso Galli; Angelini, Ronaldo; Carvalho, Adriana Rosa
The Brazilian cerrado is a global biodiversity hotspot and one of the most poorly sampled regions in the Neotropics. We describe the bird community structure among the distinct cerrado phytophysiognomies and among different periods of the day, in five environments of this biome. Bird observations were carried out from October 2003 to March 2005, by visual and acoustical records, using transect and point-count surveys. We found a total of 128 species in the area, including six species endemic to the cerrado biome, and found evidence of breeding in nine species. The bird community differed significantly among phytophysiognomies. Our data show that, even at a small spatial scale, high richness, endemism and nesting are likely to be found in the cerrado. The variation in species occurrence also reveals the unique community structure of each cerrado habitat type over time, even if the same vegetal formations were considered between habitats. Our results support the decision to convert the study site into the first university cerrado conservation unit, since this will protect a broad range of species and will guarantee habitats for some endemic birds
Diversidade de peixes recifais na praia de Barra de Tabatinga, Rio Grande do Norte
(Revista Bioikos, 2013) Souza, Thaisa Accioly de; Mendes, Liana de Figueiredo; Angelini, Ronaldo
Recifes rasos são comumente submetidos à pressões antrópicas, devido à fácil acessibilidade. O objetivo deste estudo foi comparar a diversidade, a estrutura da comunidade e a organização trófica em três setores de recifes de corais em Barra de Tabatinga, Nísia Floresta, Rio Grande do Norte entre dezembro de 2011 e março de 2012. Além disso, verificou-se a influência de variáveis ambientais sobre aqueles parâmetros utilizando métodos de censo visual. Foram encontrados 47 espécies de peixes associados aos recifes. A maioria das espécies consumiu invertebrados, padrão já observado para o Nordeste do Brasil. O índice de Shannon do Setor 1 foi diferente dos demais, o que pode estar relacionado ao grau de conectividade durante a maré seca e a proximidade com um manguezal. Por fim, não houve diferenças significativas entre as comunidades de peixes dos setores, o que sugere que a área parece ser uma única unidade. Contudo, pequenas diferenças na composição e abundância de peixes nos setores elevam a diversidade do local. Dessa forma, todos os setores contribuem para a manutenção e a conservação da área. Estes resultados podem ser úteis para futuros estudos de zoneamento e monitoramento
Integrating fishermen knowledge and scientific analysis to assess changes in fish diversity and food web structure
(Elsevier, 2014-12) Rosa, Roberto; Carvalho, Adriana Rosa; Angelini, Ronaldo
In this paper the Ecosystem Approach to Fisheries (EAF) and the Fishermen Knowledge Approach (FKA) were applied to understand changes in a tropical coastal lagoon. Then, the fishermen experience-based knowledge, literature information and data sampling were combined aiming to understand biodiversity loss and food web changing in their fishing environment exposed to the introduction of an invasive fish species. Fishermen indicated the changes in fish species composition and simplification in trophic web, confirming biological data. However they do not attributed changes to the species introduction (our ecological hypothesis previously assumed), but to the sequential construction of bridges that interrupted water flow between the lagoon and the ocean (their environmental hypothesis). This assertion fitted to Ecopath model simulations outputs in which exotic species removal from the ecosystem does not recovery fish composition or the trophic web complexity. Fishermen recalled as larger as smaller species, the matching between food web described by fishermen and the food web from literature and the justification for biodiversity loss presented by fishermen, broadened the confidence on their role as experts. This approach merged the historical views of fishermen and provided evidence on the value of complement scientific data with experts consulting
Fishers’ and scientific histories: an example of consensus from an inland fishery
(CSIRO Publishing, 2016-08-03) Philippsen, Juliana Strieder; Minte-Vera, Carolina Viviana; Okada, Edson Kiyoshi; Carvalho, Adriana Rosa; Angelini, Ronaldo
In this study we tested the basic premise that fishers’ knowledge provides similar perceptions about exploited stocks to data gathered by standardised monitoring in a small-scale commercial fishery. To that end, we compared temporal trends in catch and individual size for fish species between data obtained from interviews with fishers and a 25-year dataset from a landing monitoring program in the Itaipu Reservoir (Brazil). Fishers described with accuracy changes in species composition of the catches, from large migratory species of high commercial value (common before impoundment) to migratory species of low commercial value and sedentary species following damming. Temporal trends in catches reported by fishers and documented in the landing data matched for most species. Histories diverge when absolute values are involved, such as when fishers were asked to recall their largest catch. Fishers were homogeneous in their reports, indicating that instead of individual opinions, they revealed knowledge resulting from their observation and fishery experience. Fishers can be a reliable source of information for detecting changes in catches over time, especially when large-scale habitat changes have occurred within the time scale of a fisher career. Fishers may be key partners to be considered by managers in information gathering for effective management
Extreme drought favors potential mixotrophic organisms in tropical semi-arid reservoirs
(Springer, 2018-03-16) Becker, Vanessa; Costa, Mariana R. A.; Menezes, Rosemberg F.; Sarmento, Hugo; Attayde, José L.; Sternberg, Leonel da S. L.
Climate change is affecting the global hydrological cycle and is causing drastic changes in the freshwater hydrological regime. Water level (WL) reduction caused by drought tends to increase the concentration of nutrients favoring the dominance of cyanobacteria. We hypothesized that the WL reduction favors the dominance of cyanobacteria at regular dry conditions, but at extremely dry events mixotrophic algae would thrive because of light limitation due to increased resuspension of sediments on the water column. To test our hypothesis, we compared phytoplankton traits and water quality variables between two sets of reservoirs located in two watersheds with contrasting precipitation regimes within the Brazilian semi-arid. The reservoirs were compared in a dry period and in an extremely dry period to evaluate the response of the variables to an extreme drought. Drought intensification decreased the reservoirs’ WL and water transparency and increased the total phosphorous. Cyanobacteria dominated in the dry period, and the contribution of mixotrophic algae increased in the extremely dry period. Thus, phytoplankton with mixotrophic potential was favored by the extreme drought. This result suggests that this can be one possible scenario for phytoplankton communities in reservoirs of semi-arid regions if extreme droughts become more frequent because of climate change
Water volume reduction increases eutrophication risk in tropical semi-arid reservoirs
(Associação Brasileira de Limnologia, 2018-04-05) Becker, Vanessa; Rocha Junior, Carlos Alberto Nascimento da; Costa, Mariana Rodrigues Amaral da; Menezes, Rosemberg Fernandes; Attayde, José Luiz
Global patterns of temperature and precipitation have significantly changed over the last century and nearly all predictions point to even greater changes by the end of 2100. Long periods of drought in semi-arid regions generally reduce reservoirs and lakes water level, increasing the nutrients concentrations in the water. Our principal hypothesis is that water volume reduction, driven by prolonged droughts, will increase reservoirs susceptibility to eutrophication and accordingly an increase in trophic state. To test this hypothesis, we used a comparative analysis of ecosystems in a space-for-time substitution approach, in a Brazilian semi-arid region, to predict the consequences of reservoirs water volume reduction on key limnological variables. Methods: We sampled 16 reservoirs located in two sub-basins with contrasting rainfall regimes, inserted on Piranhas-Açu watershed. The Seridó River basin (SB) is dry and the Piancó River basin (SB) is humid, with annual mean precipitation of 500 and 700 mm, respectively. Linear regressions analyzes were performed to assess whether the percentage of maximum volume stored (%MVS) is a good predictor for total phosphorus (TP), total nitrogen (TN) and chlorophyll-a (CHLA). In addition, a two factorial analysis of variance (two-way ANOVA) was performed to test for period (dry, very dry and extremely dry), basin (SB and PB) and their interactions effects on TP, TN, CHLA, conductivity, turbidity, and Secchi depth. Results: The results showed a reduction in the reservoirs %MVS both for PB and SB regions. At the extremely dry period, all reservoirs were classified as eutrophic, but TP concentrations reached much higher values in SB than in PB. The linear regressions analyses showed that the TP and TN were negatively related to %MVS during all periods sampled. The two-way ANOVA showed that there were significant basin and period effects on TP, TN, Secchi depth and turbidity, whereas for CHLA and conductivity only basin effects were observed. In addition, we found significant interaction effects between period and basin on TP, TN and turbidity. Conclusions: We conclude that the contrasting levels of rainfall observed between the two basins affect the water quality and trophic state of the reservoirs and these effects are magnified by water volume reduction. Therefore, our findings might help to predict the consequences of rainfall reductions on freshwater ecosystems of Brazilian drylands
The use of polyaluminium chloride as a restoration measure to improve water quality in tropical shallow lakes
(Associação Brasileira de Limnologia, 2018-09-06) Araújo, Fabiana; Santos, Hélio Rodrigues dos; Becker, Vanessa; Attayde, José Luiz de
Aim: The aim of this study was to evaluate the performance of the coagulant Polyaluminium chloride (PAC) in water quality improvement of six eutrophic shallow lakes in Brazilian semiarid region. Methods: We evaluated the effect of PAC in turbidity, humic substances (UV254), total phosphorus and chlorophyll-a concentration through laboratory jar tests. Results: The results showed that PAC had a good performance in reducing total phosphorus concentrations and turbidity, with a reduced efficiency in removing chlorophyll-a and humic substances by sedimentation of flocks formed. Conclusions: Addition of PAC is a potential tool for water quality improvement of eutrophic shallow lakes in Brazilian semiarid region but its efficiency depends on the pH and particulate and dissolved organic matter concentration in the lake or reservoir water
Climate effects on fish body size–trophic position relationship depend on ecosystem type
(Wiley, 2019) Dantas, Danyhelton Douglas Farias; Silva, Adriano Caliman Ferreira da; Guariento, Rafael D.; Angelini, Ronaldo; Carneiro, Luciana Silva; Lima, Sérgio Maia Queiroz; Martinez, Pablo A.; Attayde, José Luiz de
The energetic demand of consumers increases with body size and temperature. This implies that energetic constraints may limit the trophic position of larger consumers, which is expected to be lower in tropical than in temperate regions to compensate for energy limitation. Using a global dataset of 3635 marine and freshwater ray‐finned fish species, we addressed if and how climate affects the fish body size–trophic position relationship in both freshwater and marine ecosystems, while controlling for the effects of taxonomic affiliation. We observed significant fish body size–trophic position relationships for different ecosystems. However, only in freshwater systems larger tropical fish presented a significantly lower trophic position than their temperate counterparts. Climate did not affect the fish body size–trophic position relationship in marine systems. Our results suggest that larger tropical freshwater fish may compensate for higher energetic constraints feeding at lower trophic positions, compared to their temperate counterparts of similar body size. The lower latitudinal temperature range in marine ecosystems and/or their larger ecosystem size may attenuate and/or compensate for the energy limitation of larger marine fish. Based on our results, temperature may determine macroecological patterns of aquatic food webs, but its effect is contingent on ecosystem type. We suggest that freshwater ecosystems may be more sensitive to warming‐induced alterations in food web topology and food chain length than marine ecosystems
Effects of seasonality, trophic state and landscape properties on CO2 saturation in low-latitude lakes and reservoirs
(Elsevier, 2019-05) Junger, Pedro Ciarlini; Dantas, Fabíola da Costa Catombé; Nobre, Regina Lucia Guimarães; Kosten, Sarian; Venticinque, Eduardo Martins; Araújo, Fernando de Carvalho; Sarmento, Hugo; Angelini, Ronaldo; Terra, Iagê; Gaudêncio, Andrievisk; They, Ng Haig; Becker, Vanessa; Cabral, Camila Rodrigues; Quesado, Letícia; Carneiro, Luciana Silva; Caliman, Adriano; Amado, André Megali
The role of tropical lakes and reservoirs in the global carbon cycle has received increasing attention in the past decade, but our understanding of its variability is still limited. The metabolism of tropical systems may differ profoundly from temperate systems due to the higher temperatures and wider variations in precipitation. Here, we investigated the spatial and temporal patterns of the variability in the partial pressure of carbon dioxide (pCO2) and its drivers in a set of 102 low-latitude lakes and reservoirs that encompass wide gradients of precipitation, productivity and landscape properties (lake area, perimeter-to-area ratio, catchment size, catchment area-to-lake area ratio, and types of catchment land use). We used multiple regressions and structural equation modeling (SEM) to determine the direct and indirect effects of the main in-lake variables and landscape properties on the water pCO2 variance. We found that these systems were mostly supersaturated with CO2 (92% spatially and 72% seasonally) regardless of their trophic status and landscape properties. The pCO2 values (9–40,020 μatm) were within the range found in tropical ecosystems, and higher (p < 0.005) than pCO2 values recorded from high-latitude ecosystems. Water volume had a negative effect on the trophic state (r = −0.63), which mediated a positive indirect effect on pCO2 (r = 0.4), representing an important negative feedback in the context of climate change-driven reduction in precipitation. Our results demonstrated that precipitation drives the pCO2 seasonal variability, with significantly higher pCO2 during the rainy season (F = 16.67; p < 0.001), due to two potential main mechanisms: (1) phytoplankton dilution and (2) increasing inputs of terrestrial CO2 from the catchment. We conclude that at low latitudes, precipitation is a major climatic driver of pCO2 variability by influencing volume variations and linking lentic ecosystems to their catchments
Following the fish: the role of subsistence in a fish-based value chain
(Elsevier, 2019-05) Bevilacqua, Ana Helena V.; Angelini, Ronaldo; Steenbeek, Jeroen; Christensen, Villy; Carvalho, Adriana Rosa
This study evaluated the socioeconomic benefits generated by the small-scale fisheries sector based on a socio-economic modeling approach using the value chain plugin in the Ecopath with Ecosim (EwE) software system. Based on an EwE ecosystem model for the Baía Formosa area in Rio Grande do Norte State (Northeast Brazil), a value chain with 14 components was described, including four producers (divided by vessel size categories: sailboat, small, medium, and large engine boat), four processors and distributors, two retailers (in two categories, street markets and restaurants), and three different final consumers (local consumers, subsistence, and tourism). The data was obtained through face-to-face interviews (n = 154) performed between February and November 2014 using the snowball method and tracking the fish around nearby cities. The total revenue from the primary producers (i.e. fishers) was estimated to be US$11 million in 2014. All sectors (including sellers and retailers) encompassed about US$ 44.5 million per year, contributing around US$ 16 million to the GDP. Overall, the price per ton increased three times from it was landed, while employment generation on land was twice that found at sea. Local consumers obtained roughly 66% of production, while subsistence fishers consumed 28% of what was caught. The lowest portion went to tourist consumption (6%). Fish production flowed to local markets and fishers' tables, revealing a clear bias toward the consumption of seafood by local dwellers and the subsistence of local fishers. Few studies have quantified the role of small-scale fishing in providing household income, job creation, and contribution to the GDP. By neglecting such economic and social reliance on natural resource conservation and under the current lack of conservation policies, not only may overfishing become a threat to fishers, but policy makers, managers, and users may inadvertently compromise the continuation of the activity
Fisheries and trophic structure of a large tropical river under impoundment
(Elsevier, 2020) Lima, Maria Alice Leite; Doria, Carolina Rodrigues da Costa; Carvalho, Adriana Rosa; Angelini, Ronaldo
Impacts on tropical rivers affect biodiversity and ecosystem services negatively impacting many economic activities, such as small-scale fisheries. Ecosystem-based fisheries management (EBFM) has been applied to maintain ecosystem flows and services for fisheries, to support social and economic sustainability. The suitable employment of the EBFM approach requires the understanding of the ecosystem by quantifying the trophic interactions and simulating environmental and fishery alterations. In this paper, to evaluate the early changes resulting from damming for hydroelectric power generation on the Madeira River food web, we compared two Ecopath models: before (pre) and after (post) the dam construction in November 2011. We analyzed the changes using several ecosystem attributes: fish biomass, catches, exchange of matter/energy, transfer efficiency, and, especially, the potential direct and indirect relationships among species. We also carried out simulations of the increase in the catches of several stocks in the models. Our analysis allowed us to identify several differences between before (2010–2011) and post (2012–2013) periods: an increasing of the ecosystem’s respiration and consumption, a reducing of net production, transfer efficiency among Trophic Levels (TL), and total biomass of fish species by half. There was also an exchange of key species that were previously mostly non-fish compartments and became top predator fish, including B. rousseauxii, which was considered a key species in both periods. Fish species with an intermediate TL had their biomass reduced via top-down control, especially because of the increased biomass of non-migratory top predators (Hoplias malabaricus and Plagioscion squamosissimus). Noticeably, damming clearly reversed possible impact linkage among species, since one-third of indirect and almost one-half of direct (trophic) relations changed of signal, leading to unexpected turns in the system. Also, simulation revealed that increasing in catches strongly impact on fish biomass in the post-dam model more than in the pre-dam model. The ecosystem context of these results and the fact that they are pioneers in assess Amazonian damming can help the local managers and government to understand the impoundment effects and simulate changes in catches to foresee future impacts of reservoirs on Amazon
Declining fisheries and increasing prices: the economic cost of tropical rivers impoundment
(Elsevier, 2020) Lima, Maria Alice Leite; Carvalho, Adriana Rosa; Nunes, Marcus Alexandre; Angelini, Ronaldo; Doria, Carolina Rodrigues da Costa
This work tests the null hypothesis that the coefficients of the total landings, landed values, mean catches and price per kg of migratory and resident species are constant over time following the installation of two large run-of-the-river hydroelectric dams in a large tropical river. To identify shifts in catches and economic returns due to river impoundment, we inspected daily landing data (25-year time series) and wholesale prices (19-year time series) for the Madeira River, the largest tributary of the Amazon River. Our results show that the period of decreasing catches and increasing prices observed for fisheries in the Madeira River matched the timings of the construction of the two dams. According to the results, both dams quickly changed catches and fish supply to market, which were immediately echoed in the price per kg of exploited fish species. Following the dam construction, prices rose for both fish that became scarce and fish that became abundant. Though catches declined 58% in 25 years, the price increased 49% over the same period, representing a high economic cost for the local population. Further, there was a clear decline in the catches of some species (e.g., the dourada and the curimatã), but increased catches of others (e.g., the sardine and the tucunaré). Moreover, some fluctuation patterns across years showed natural oscillations, or changes, in local habitats and even fishing efforts
Um laboratório a céu aberto: educação para biodiversidade na formação em nutrição com uso do método da aprendizagem baseada em hortas
(Desenvolvimento e Meio Ambiente, 2021-05-27) Mota, Ana Carolina Costa Campos; Gomes,Ana Francisca Teixeira; Porciúncula, Laura Brito; Chaves, Viviany Moura; Almeida, Adriana Monteiro de; Jorge, Thiago Perez; Jacob, Michelle Cristine Medeiros; https://orcid.org/0000-0001-5503-0096; https://orcid.org/0000-0003-1265-0089; https://orcid.org/0000-0002-9654-7152; https://orcid.org/0000-0001-5447-8593; https://orcid.org/0000-0002-0375-8613; https://orcid.org/0000-0002-4881-7285
No campo da nutrição, há uma demanda crescente por recursos humanos com capacidade para promover dietas sustentáveis. A ciência da nutrição, no entanto, enfrenta desafios que limitam sua capacidade de criar uma força de trabalho adequada para responder a essa demanda. A falta de conhecimento sobre biodiversidade, central para as dietas sustentáveis, é uma delas. Essa deficiência é parcialmente causada por tradições fragmentadas de pensamento – social, ambiental e biológico – na área. Argumentamos que a educação para biodiversidade, com o apoio do método de Aprendizagem Baseada em Hortas (ABH), podem ajudar a abordar esse limite. O estudo é um relato de experiência de professores e alunos envolvidos em um laboratório horta em um curso de nutrição de uma universidade pública do nordeste do Brasil. Descrevemos o histórico, o design e a metodologia de trabalho do laboratório, focada no tema de Plantas Alimentícias Não Convencionais. Apresentamos exemplos da aplicação do método a partir de experiências com plantas estudadas em 2019.O uso do método ABH proporcionou oportunidades para ação objetivando o enfrentamento dos desafios apresentados pela educação para biodiversidade: discussão sobre a formação dos professores, institucionalização do laboratório, inclusão de um curso sobre Sistemas alimentares sustentáveis no currículo, trabalho com uma equipe multiprofissional, fortalecimento dos laços comunitários e adaptação de ferramentas para contextos transculturais. Nessas ações, abordamos sistematicamente o conhecimento sobre taxonomia, filogenia, ecossistemas e diversidade cultural. A escassez de literatura sobre o assunto limitou nossa capacidade de analisar nosso trabalho dentro de um quadro prévio de referências. Esperamos que nosso relato possa incentivar iniciativas semelhantes, orientando o uso do método. Em pesquisas futuras, pretendemos medir o impacto dessas estratégias no desenvolvimento de competências para trabalho com a biodiversidade na formação em nutrição

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