DECOL - Departamento de Ecologia

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

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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
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
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
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
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
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
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

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