Navegando por Autor "Dirzo, Rodolfo"
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Item Are protected populations of two globular cactus species facing a demographic explosion or just a “bonanza” year?(2020) Itabaiana, Yasmine Antonini; Dirzo, Rodolfo; Portela, Rita de Cássia QuiteteDespite decades of research, controversy has emerged as to whether positive and negative interactions predictably shift with increasing environmental stress. We used projection matrices, to determine growth rate and elasticity and a LTR experiment to quantify the contribution of each matrix elements to the differences in λ observed between sympatric and syntopic sub-populations of globular cactus species in Brazil (Discocactus placentiformis and D. pseudoinsignis). We addressed the following questions: What is the growth rate of the two species when in sympatry and syntopy? What are the relative contributions of survival, growth, and fecundity to population growth? Which life cycle stages have the highest mortality? Do demographic differences between the two species account for observed differences in sub-population sizes? Both species exhibited higher densities when in syntopy than in sympatry. Seedling establishment and survival were high, and fecundity increased as plant diameter increased. Asymptotic population growth rates were significantly greater than one. The highest elasticity values were for stasis for the later ontogenetic stage and for the growths. It seems that the protection provided by the conservation area is efficient, and that the data were collected during a “bonanza” year, with high rainfall, when all or most reproduction and/or recruitment occur.Item Biodiversity and ecosystem services in the campo rupestre : a road map for the sustainability of the hottest Brazilian biodiversity hotspot.(2020) Fernandes, Geraldo Wilson Afonso; Garcia, Lucas Arantes; Silva Júnior, Milton Barbosa da; Barbosa, Newton Pimentel de Ulhôa; Batista, Eugênia Kelly Luciano; Silva, Wallace Beiroz Imbrosio da; Resende, Fernando de Moura; Abrahão, Anna; Almada, Emmanuel Duarte; Alves, Elaine; Alves, Natacha Jordania da Silva; Angrisano, Patrícia; Arista, Montserrat; Arroyo, Juan; Arruda, André Jardim; Bahia, Thaíse de Oliveira; Braga, Laura; Brito, Lilian de Almeida; Pereira, Marcos Callisto de Faria; Paiva, Dario Caminha; Carvalho, Marilia; Conceição, Abel Augusto; Costa, Lêda Naiara Pereira; Cruz, Antônio Jorge do Rosário; Blum, Jessica Cunha; Dagevos, John; Dias, Braulio Ferreira de Souza; Pinto, Victor Diniz; Dirzo, Rodolfo; Domingos, Daniel Quedes; Andrade, Livia Echternacht; Fernandes, Stephannie; Figueira, José Eugênio Côrtes; Fiorini, Cecília Fonseca; Giulietti, Ana Maria; Gomes, Augusto; Gomes, Vanessa Matos; Gontijo, Bernardo Machado; Goulart, Fernando Figueiredo; Guerra, Tadeu José de Abreu; Junqueira, Patrícia A.; Santos, Débora Lima; Nascimento, Julia Marques; Meira Neto, João Augusto Alves; Miola, Deise T. B.; Morellato, Leonor Patricia Cerdeira; Negreiros, Daniel; Paula, Elizabeth Neire da Silva Oliveira de; Neves, Ana Carolina; Neves, Frederico de Siqueira; Novais, Samuel Matos Antunes de; Oki, Yumi; Oliveira, Elizabeth; Oliveira, Rafael Silva; Pivari, Marco Otávio Dias; Pontes Junior, Euripedes; Ranieri, Bernardo Dourado; Ribas, Rodrigo Pinheiro; Scariot, Aldicir Osni; Schaefer, Carlos Ernesto Gonçalves Reynaud; Sena, Letícia; Silva, Pedro Giovâni da; Siqueira, Paulo Ricardo; Soares, Natalia Costa; Soares Filho, Britaldo Silveira; Solar, Ricardo Ribeiro de Castro; Tabarelli, Marcelo; Vasconcellos, Rogério Pinto; Vilela, Evaldo Ferreira; Silveira, Fernando Augusto de Oliveira eGlobal sustainability rests on a myriad of benefits provided by natural ecosystems that support human livelihoods and well-being, from biodiversity persistence to climate regulation. The undeniable importance of conserving tropical forests has drawn most of the conservation spotlight towards it. However, open ecosystems such as the Brazilian Campo Rupestre (rupestrian grassland), have been historically overlooked despite their high diversity and key associated ecosystem services. We highlight major current threats to the persistence of the Campo Rupestre emphasizing its ecological, social, cultural, geoenvironmental, and economic importance. We call attention to the importance of the Campo Rupestre as a reservoir of biodiversity and ecosystem services and offer priority actions that resulted from discussions involving scientists, industry representatives, environmental managers, and other members of civil society. Proposed actions include efforts related to ecological restoration, sustainable ecotourism, protection of traditional ecological knowledge, identification of emerging research questions, and development of tailored public policies. Such issues are integrated into a framework that collectively represents a road map to safeguard the Campo Rupestre from further degradation and steer its historical overexploitation towards sustainable management. Safeguarding the future of non-forest biomes like this poses a challenge to current paradigms of nature conservation. By establishing priorities and guidelines, we propose an actionable plan, which we hope can support informed decision-making policy towards a sustainable use of the Campo Rupestre.Item Deep into the mud : ecological and socio-economic impacts of the dam breach in Mariana, Brazil.(2016) Fernandes, Geraldo Wilson Afonso; Goulart, Fernando F.; Ranieri, Bernardo Dourado; Coelho, Marcel Serra; Dales, Kirsten; Boesche, Nina; Bustamante, Mercedes Maria da Cunha; Carvalho, Felipe A.; Carvalho, Daniel Cardoso de; Dirzo, Rodolfo; Fernandes, Stephannie; Galetti Júnior, Pedro Manoel; Garcia Millan, Virginia Elena; Mielke, Christian; Ramirez Malaver, Jorge Luis; Neves, Ana; Rogass, Christian; Ribeiro, Sérvio Pontes; Scariot, Aldicir; Soares Filho, BritaldoWe review the ecological and socio-economic impacts ofthe catastrophic dam failure in Mariana, Brazil. Tailing management practices by Samarco mining company ultimately caused a dam breach that abruptly discharged between 55 and 62millionm3 of tailings into the Doce River watershed. On November 5th, 2015, a tsunami of slurry engulfed the small district of Bento Rodrigues, loading the Doce River and its estuary with toxic tailings along a 663.2 km trajectory, extending impacts to the Atlantic coast. Acute ecological impacts will adversely affect livelihoods of more than 1 million people in 41 riparian municipalities by reducing local access to fisheries resources, clean water, crop production sites, hydroelectric power generation and raw materials. The threats to riverine human communities are particularly critical for the disadvantaged populations from remote areas that rely on subsistence agriculture and fisheries, and are uniquely vulnerable to long-term heavy metal exposure. At the landscape scale, we predict multiple negative impacts, ranging from alterations of the genetic diversity of fish populations to long-term vegetation loss and poor regeneration in contaminated areas. Consequently, compromised soil stability and runoff control will increase the risk of further geomorphologic disturbance, including landslides, bank failure and mass movements. We propose spatially explicit long-term monitoring frameworks and priority mitigation measures to cope with acute and chronic risks. We posit that, from a national perspective, disastrous impacts like that of Doce River may become more frequent, given the recent regulatory changes that undermine both institutional governance structures and enforcement of environmental regulation.Item Patterns of orchid bee species diversity and turnover among forested plateaus of central Amazonia.(2017) Itabaiana, Yasmine Antonini; Machado, Carolina de Barros; Galetti Júnior, Pedro Manoel; Oliveira, Marcio; Dirzo, Rodolfo; Fernandes, Geraldo Wilson AfonsoThe knowledge of spatial pattern and geographic beta-diversity is of great importance for biodiversity conservation and interpreting ecological information. Tropical forests, especially the Amazon Rainforest, are well known for their high species richness and low similarity in species composition between sites, both at local and regional scales. We aimed to determine the effect and relative importance of area, isolation and climate on species richness and turnover in orchid bee assemblages among plateaus in central Brazilian Amazonia. Variance partitioning techniques were applied to assess the relative effects of spatial and environmental variables on bee species richness, phylogeny and composition. We hypothesized that greater abundance and richness of orchid bees would be found on larger plateaus, with a set of core species occurring on all of them. We also hypothesized that smaller plateaus would possess lower phylogenetic diversity. We found 55 bee species distributed along the nine sampling sites (plateaus) with 17 of them being singletons. There was a significant decrease in species richness with decreasing size of plateaus, and a significant decrease in the similarity in species composition with greater distance and climatic variation among sampling sites. Phylogenetic diversity varied among the sampling sites but was directly related to species richness. Although not significantly related to plateau area, smaller or larger PDFaith were observed in the smallest and the largest plateaus, respectively.Item Riparian forest restoration as sources of biodiversity and ecosystem functions in anthropogenic landscapes.(2022) Itabaiana, Yasmine Antonini; Beirão, Marina do Vale; Costa, Fernanda Vieira da; Azevedo, Cristiano Schetini de; Wojakowski, M. M.; Kozovits, Alessandra Rodrigues; Pires, Maria Rita Silvério; Sousa, Hildeberto Caldas de; Messias, Maria Cristina Teixeira Braga; Fujaco, Maria Augusta Gonçalves; Leite, Mariangela Garcia Praça; Martins, Joice Paiva Vidigal; Monteiro, Graziella França; Dirzo, Rodolfo1. Restoration of tropical riparian forests is challenging, since these ecosystems are the most diverse, dynamic, and complex physical and biological terrestrial habitats. This study tested whether biodiversity can predict ecosystem functions in a human-impacted tropical riparian forest. 2. We explored the effects of several biodiversity components (taxonomic or functional groups) on different ecosystem functions associated with restored riparian forests 3. Overall, 49% of the biodiversity components showed positive effects on ecosystem functions, each component to a different degree. In general, our results showed that both taxonomic and functional biodiversity had strong effects on ecosystem functions indicating that floral and faunal biodiversity enhanced the multifunctionality of these restored riparian tropical forests. 4. These findings indicate that in restored riparian forests, recovery of biodiversity is followed by improvement in important ecosystem functions that are the basis for successful restoration. Future research and policy for restoration programs must focus on restoring elementary faunal and floral components of biodiversity in order to promote ecosystem multifunctionality.