24 research outputs found

    Small forest losses degrade stream macroinvertebrate assemblages in the eastern Brazilian Amazon

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    Generally, habitat loss and fragmentation negatively affect biota, often in nonlinear ways. Such nonlinear responses suggest the existence of critical limits for habitat loss beyond which taxa experience substantial changes. Therefore, we identified change points for aquatic macroinvertebrate assemblages at both local-riparian and catchment extents in response to a forest-loss gradient in agriculture-altered landscapes of 51 small (1st to 3rd Strahler order) eastern Amazon streams. We used Threshold Indicator Taxa Analysis (TITAN) to identify change points for individual taxa and segmented regression analysis for assemblage richness. Considering the patterns of the cumulative frequency distributions of sum(Z−) maxima across bootstrap replications, peak changes in macroinvertebrate assemblages were at ∼9% (5–95 percentiles = 1–15%) of forest-loss at the catchment extent, and at ∼1.4% (5–95 percentiles = 0–35%) of forest-loss at the local-riparian extent. Although the assemblage change point at the site extent was less than that detected at the catchment extent, the markedly lower percentile range indicates that biotic assemblages are more clearly responsive to forest-loss at the catchment/network-riparian extents than the site extent. For catchment and site extents, segmented regression analysis determined a change point for assemblage richness at 57% and 79% of forest-loss, respectively. This indicates the low capacity of total richness to separate early and synchronous decreases of sensitive taxa from gradual increases of tolerant taxa. Our results also show that it is not enough to focus management and conservation actions on riparian zones, but that conservation strategies should be expanded to entire catchments as well. The sharp decline of sensitive taxa in response to removal of a small portion of forest cover, even at catchment extents, indicates that the Brazilian Forest Code is insufficient for protecting stream macroinvertebrates. Consequently, we recommend strategies to reverse the potential collapse of aquatic biodiversity, particularly through avoiding deforestation and forest degradation, encouraging socio-economic incentives for restoring degraded areas, creating protected areas, and maintaining the current protected areas. We argue that reducing habitat loss should be a top priority for conservation planners in tropical forests because the sensitivity of aquatic biodiversity to removal of riparian forest-cover in Amazon rainforests is higher than previously thought. Therefore, the Forest Code regulatory framework needs complementary regulation that may be achived by more restrictive State and biome policies. © 2019 Elsevier Lt

    Estudos paleoambientais interdisciplinares: dinâmica da vegetação, do ambiente marinho e inferências climáticas milenares a atuais na Costa Norte do Espírito Santo, Brasil

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    Estudos paleoambientais desde ~50.000 anos na costa do Brasil e, em particular, no litoral do Espírito Santo, são ainda insuficientes para servir de base a reconstituições da dinâmica da vegetação, de oscilações do nível relativo do mar e de flutuações climáticas e respectivas influências sobre a ação humana milenar. Para obter essas informações, uma equipe interdisciplinar, financiada por projetos temáticos FAPESP e CNPq, desenvolveu pesquisas correlatas na Reserva Natural Vale (RNV) e região. Para a caracterização da dinâmica da vegetação e marinha, com inferências climáticas, em locais de floresta de tabuleiros e campos naturais da RNV e região desde ~16.000 anos, utilizaram-se isótopos do C (12C, 13C e 14C) da matéria orgânica do solo e sedimentar, além de palinologia em sedimentos lacustres e terrestres. No estudo da dinâmica do ecótono floresta – campo, apresentam-se inferências preliminares sobre a evolução pedogenética dos Espodossolos associados ao campo, com ênfase às suas características físico-químicas, e também dos Argissolos, encontrados sob floresta. Finaliza-se com o estágio inicial de uma coleção de referência de fitólitos, bioindicador de vegetação utilizado em estudos paleoambientais, extraídos de plantas da floresta de tabuleiros da RNV.A equipe agradece todo o empenho dos funcionários e apoio logístico da Reserva Natural Vale, Linhares, Espírito Santo; à FAPESP através do projeto Temático 2011/00995-7 (ProjES); e ao CNPq – Universal 2012-5/470210, pelo aporte financeiro e a colaboração dos técnicos do Laboratório 14C, Liz Mary Bueno de Moraes e Thiago Casemiro Barrios de Campos, na preparação de amostras gasosas para a datação 14C.Peer Reviewe

    Anales del III Congreso Internacional de Vivienda y Ciudad "Debate en torno a la nueva agenda urbana"

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    Acta de congresoEl III Congreso Internacional de Vivienda y Ciudad “Debates en torno a la NUEVa Agenda Urbana”, ha sido una apuesta de alto compromiso por acercar los debates centrales y urgentes que tensionan el pleno ejercicio del derecho a la ciudad. Para ello las instituciones organizadoras (INVIHAB –Instituto de Investigación de Vivienda y Hábitat y MGyDH-Maestría en Gestión y Desarrollo Habitacional-1), hemos convidado un espacio que se concretó con potencia en un debate transdisciplinario. Convocó a intelectuales de prestigio internacional, investigadores, académicos y gestores estatales, y en una metodología de innovación articuló las voces académicas con las de las organizaciones sociales y/o barriales en el Foro de las Organizaciones Sociales que tuvo su espacio propio para dar voz a quienes están trabajando en los desafíos para garantizar los derechos a la vivienda y los bienes urbanos en nuestras ciudades del Siglo XXI

    Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

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    Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure <= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

    Riparian forest management and regeneration : effects on forest structure and stream ecological processes in streams of eastern Amazon, Brazil

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    In tropical areas, deforestation and forest degradation are major threats to forests and the surrounding ecosystems, such as riparian forests and streams. These threats to riparian forests and streams in agricultural areas can be reduced by the implementation of riparian buffers. However, disturbances from cleared areas may still impact the forests due to the high edge-to-area ratio of buffers. Selective logging inside the buffers also has the potential to degrade riparian forests and streams. Forest regeneration has the potential to restore ecosystems in degraded lands, but disturbances from ongoing agriculture are expected to arrest or delay the regeneration process in the buffers. I evaluated the efficacy of two riparian buffer management strategies: (1) land abandonment for natural regeneration and (2) the maintenance of mature forest. I also sampled additional sites of different ages to evaluate where buffer treatments fit after riparian forest alterations. I hypothesized that the riparian buffers resulting from land abandonment would have less forest canopy, simpler stand structure, less large wood, higher primary production, and higher decomposition rates than a regenerated riparian forest that was surrounded by mature forest. I expected the same outcomes when comparing the riparian buffers of mature forest versus mature riparian reference sites. I found that forest structure did not differ significantly between riparian buffer management treatments, however, my ordination analysis revealed signs of forest degradation after selective logging in the riparian buffers of mature forest. I found no significant effect of riparian buffer management in any stream variable studied. Large wood was related to channel width and stem density. Stream respiration increased and primary production decreased as the regeneration process advances. Decomposition differed among species, apparently by differences on leaf structural compounds. My results show that both buffer management strategies can be effective for protection of riparian and stream ecosystem in agricultural landscapes. Land abandonment is a viable and inexpensive restoration action where ongoing disturbances are mild and the propagules for regeneration are available. While the implementation of riparian buffers of mature forests is an effective strategy, selective logging should be excluded from these areas as disturbances may intensify in the future.Forestry, Faculty ofGraduat

    Large Woody Debris Input and Its Influence on Channel Structure in Agricultural Lands of Southeast Brazil

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    Riparian forests are important for the structure and functioning of stream ecosystems, providing structural components such as large woody debris (LWD). Changes in these forests will cause modifications in the LWD input to streams, affecting their structure. In order to assess the influence of riparian forests changes in LWD supply, 15 catchments (third and fourth order) with riparian forests at different conservation levels were selected for sampling. In each catchment we quantified the abundance, volume and diameter of LWD in stream channels; the number, area and volume of pools formed by LWD and basal area and tree diameter of riparian forest. We found that riparian forests were at a secondary successional stage with predominantly young trees (diameter at breast height < 10 cm) in all studied streams. Results showed that basal area and diameter of riparian forest differed between the stream groups (forested and non-forested), but tree density did not differ between groups. Differences were also observed in LWD abundance, volume, frequency of LWD pools with subunits and area and volume of LWD pools. LWD diameter, LWD that form pools diameter and frequency of LWD pools without subunits did not differ between stream groups. Regression analyses showed that LWD abundance and volume, and frequency of LWD pools (with and without subunits) were positively related with the proportion of riparian forest. LWD diameter was not correlated to riparian tree diameter. The frequency of LWD pools was correlated to the abundance and volume of LWD, but characteristics of these pools (area and volume) were not correlated to the diameter of LWD that formed the pools. These results show that alterations in riparian forest cause modifications in the LWD abundance and volume in the stream channel, affecting mainly the structural complexity of these ecosystems (reduction in the number and structural characteristics of LWD pools). Our results also demonstrate that riparian forest conservation actions must consider not only its extension, but also successional stage to guarantee the quantity and quality of LWD necessary to enable the structuring of stream channels.FAPESP[Proc. 06/00797-2]FAPESP[06/04723-3]FAPESP[03/10505-0

    Influence of landscape properties on stream water quality in agricultural catchments in Southeastern Brazil

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    Changes in land cover, especially the replacement of forest by agricultural activities affect the hydrological processes of river catchments, resulting in physical and chemical compositional changes of water draining from affected basins. The aim of this study was to evaluate landscape influences at different spatial scales (catchment and riparian) on the physical and chemical composition of stream water in 15 agricultural catchments, belonging to the Corumbatai basin (Brazil). We calculated the average slope (%), average elevation (m), soil classes (%), major land use classes (%), average distance from the forest cover in relation to the hydrographic network (m), largest patch index (%) at the catchment scale and riparian zone of drainage network scale within a 30 m buffer. Water samples were collected in two seasons (dry and rainy) to characterize physical and chemical properties: turbidity, suspended solids, total nitrogen, nitrate and total phosphorus. Our results showed higher concentration of nitrate in sugarcane fields and larger amount of suspended solids and turbidity in pasture areas. We concluded that degraded and highly fragmented forests may not be effectively contributing toward the protection of aquatic ecosystems.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Biological indicators of diversity in tropical streams: Congruence in the similarity of invertebrate assemblages

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    Surrogate indicators are important alternatives to overcome the shortage of total biodiversity data for planning and implementing conservation measures. The most important premise of this approach is congruence among surrogate candidates and among different assemblages. The aim of this study was to evaluate abundance and incidence congruence between invertebrate assemblages at two taxonomic resolutions (genus and family), and between invertebrate assemblage (genus) and three groups of taxa (EPT, Odonata, and Trichoptera). We also evaluated the congruence between functional groups of EPT and the taxonomic groups listed above. Data were collected from 51 stream sites distributed along a disturbance gradient in the rural area of the Paragominas municipality of the state of Pará Brazil. We used Procrustes analysis to test congruence between invertebrate assemblages at the multiple taxonomic resolutions listed previously. Family taxonomic level was a good substitute for similarity patterns measured at the genera level. EPT genus also were highly congruent with whole invertebrate assemblage (genus level) variation. Trichoptera had greater congruence with all macroinvertebrate genera than did Odonata. The congruence between EPT functional groups and groups of taxa was greater than r = 0.70. In general, taxonomic and functional metrics responded similarly to environmental conditions (water quality, channel morphology, substrate, riparian vegetation cover). Trichoptera (abundance), EPT (genera and functional groups), or invertebrate families appear to be reasonable surrogates for Amazon stream invertebrate assemblage as biological indicators for assessing and conserving streams influenced by agriculture. © 2017 Elsevier Lt

    The role of secondary riparian forests for conserving fish assemblages in eastern Amazon streams

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    Riparian deforestation degrades stream habitats, altering fish assemblages’ structure, and composition. In contrast, secondary riparian forests can recover stream habitats and fish assemblages as they recover structural attributes and ecological processes. We evaluated whether the amount and condition of secondary riparian forests were important to conserve fish assemblages in 49 streams sites in eastern Amazonia. We related fish assemblage taxonomic and functional measures to riparian forest amount plus different habitat metrics using regression analysis. We compared assemblage measures among reference forests, abandoned pastures (open canopy), and secondary forests (closed canopy) using ANOVA tests. The amount of secondary forests had little influence on fish assemblages. Species richness, diversity, and functional richness were higher in pasture than in reference sites but returned to pre-disturbance conditions in secondary sites. However, functional evenness was lower in pasture streams and did not recover after secondary forest regrowth. Our results show that secondary riparian forest condition is important to recover some aspects of fish assemblages. However, streams bordered by these forests may have impoverished fish assemblages because some lost sensitive species may take longer to return. Avoiding riparian deforestation is the best strategy to reduce losses in aquatic biodiversity and ecosystem functions in tropical agricultural landscapes
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