Impacts of hydroelectric dams on alluvial riparian plant communities in eastern Brazilian Amazonian

“…This study demonstrates that periodic disturbances and stresses associated with the hydrological regime are a fundamental component of the ecological integrity of every wetland ecosystem (Ward and Stanford 1995 ). This link between the fl oodplain forest and local hydrology suggests that changes in fl ood regimes due to climate variability and dam construction in the Amazon Basin will impact the growth, diversity, and composition of Amazonian fl oodplain forests (Ferreira et al 2013 ).…”

Section: Seasonal Fl Ooding As a System Driver Of Forest Integritymentioning

confidence: 74%

“…This link between the floodplain forest and local hydrology suggests that changes in flood regimes due to climate variability and dam construction in the Amazon Basin will impact the growth, diversity, and composition of Amazonian floodplain forests (Ferreira et al. ).…”

Section: Discussionmentioning

confidence: 99%

How livestock and flooding mediate the ecological integrity of working forests in Amazon River floodplains

Lucas

Sheikh

Gagnon

et al. 2016

Ecological Applications

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The contribution of working forests to tropical conservation and development depends upon the maintenance of ecological integrity under ongoing land use. Assessment of ecological integrity requires an understanding of the structure, composition, and function and major drivers that govern their variability. Working forests in tropical river floodplains provide many goods and services, yet the data on the ecological processes that sustain these services is scant. In flooded forests of riverside Amazonian communities, we established 46 0.1-ha plots varying in flood duration, use by cattle and water buffalo, and time since agricultural abandonment (30-90 yr). We monitored three aspects of ecological integrity (stand structure, species composition, and dynamics of trees and seedlings) to evaluate the impacts of different trajectories of livestock activity (alleviation, stasis, and intensification) over nine years. Negative effects of livestock intensification were solely evident in the forest understory, and plots alleviated from past heavy disturbance increased in seedling density but had higher abundance of thorny species than plots maintaining low activity. Stand structure, dynamics, and tree species composition were strongly influenced by the natural pulse of seasonal floods, such that the defining characteristics of integrity were dependent upon flood duration (3-200 d). Forests with prolonged floods ≥ 140 d had not only lower species richness but also lower rates of recruitment and species turnover relative to forests with short floods <70 d. Overall, the combined effects of livestock intensification and prolonged flooding hindered forest regeneration, but overall forest integrity was largely related to the hydrological regime and age. Given this disjunction between factors mediating canopy and understory integrity, we present a subset of metrics for regeneration and recruitment to distinguish forest condition by livestock trajectory. Although our study design includes confounded factors that preclude a definitive assessment of the major drivers of ecological change, we provide much-needed data on the regrowth of a critical but poorly studied ecosystem. In addition to its emphasis on the dynamics of tropical wetland forests undergoing anthropogenic and environmental change, our case study is an important example for how to assess of ecological integrity in working forests of tropical ecosystems.

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“…Outros autores já encontraram elevada influência das inundações sobre a composição florístico-estrutural (e.g. FERREIRA, 2000;BIANCHINI et al, 2003;BARDDAL et al, 2004;SILVA et al, 2007;2009;FERREIRA et al, 2013) e sobre a dinâmica em florestas (e.g. APPOLINARIO; OLIVEIRA FILHO; GUILHERME, 2005;SILVA et al, 2011;NUNES et al, 2016).…”

Section: Resultsunclassified

Impacto Do Enchimento Do Reservatório De Uma Uhe Sobre a Dinâmica De Um Fragmento De Floresta Ombrófila Mista Em Santa Catarina

et al. 2018

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O presente estudo teve como objetivo investigar o impacto do enchimento do reservatório de uma usina hidrelétrica sobre as taxas de dinâmica do componente arbóreo em uma floresta adjacente. Para isso, foram alocadas 48 parcelas em três setores do fragmento: adjacente às margens do reservatório, meio da encosta e topo da encosta. Um ano após o enchimento do reservatório, todos os indivíduos arbóreos com circunferência a altura do peito (CAP) ≥ 15,7 cm foram avaliados (identificados e mensurados), e dois anos após o enchimento foi realizado o estudo de dinâmica, com as árvores sobreviventes remedidas, as mortas quantificadas e as recrutas incorporadas. Foi realizado o levantamento das variáveis ambientais edáficas, topográficas, de abertura do dossel e de impacto ambiental. Foram calculadas as taxas de dinâmica. Para ordenação das variáveis ambientais foi aplicada uma Análise de Componentes Principais (PCA) e a influência de gradientes ambientais sobre as taxas demográficas da comunidade foi verificada por meio de regressão logística. A dinâmica apresentou estabilidade no número de indivíduos, porém, com maior ganho (3,64%.ano-1) que perda (1,62%.ano-1) em área basal. Entre os setores houve distinções, sendo o setor 1 caracterizado pela maior taxa de perda em área basal (2,51%.ano-1). Houve pouca relação das taxas demográficas com as variáveis ambientais analisadas, indicando que a maior influência encontrada sobre o crescimento das árvores está associada a variáveis não mensuradas. O presente estudo indica que, dois anos após o enchimento do reservatório, foi possível perceber os primeiros efeitos da influência do lago da hidrelétrica na comunidade arbórea.

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Impacts of hydroelectric dams on alluvial riparian plant communities in eastern Brazilian Amazonian

Cited by 74 publications

References 15 publications

Health Impact Assessment of the construction of hydroelectric dams in Brazil

Health Impact Assessment of the construction of hydroelectric dams in Brazil

How livestock and flooding mediate the ecological integrity of working forests in Amazon River floodplains

Impacto Do Enchimento Do Reservatório De Uma Uhe Sobre a Dinâmica De Um Fragmento De Floresta Ombrófila Mista Em Santa Catarina

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