Vera M. F. da Silva

Bio: Vera M. F. da Silva is an academic researcher from National Institute of Amazonian Research. The author has contributed to research in topics: Inia geoffrensis & Amazonian manatee. The author has an hindex of 19, co-authored 89 publications receiving 1433 citations. Previous affiliations of Vera M. F. da Silva include University of Porto & Wageningen University and Research Centre.

A new species of river dolphin from Brazil or: how little do we know our biodiversity.

Abstract: True river dolphins are some of the rarest and most endangered of all vertebrates. They comprise relict evolutionary lineages of high taxonomic distinctness and conservation value, but are afforded little protection. We report the discovery of a new species of a river dolphin from the Araguaia River basin of Brazil, the first such discovery in nearly 100 years. The species is diagnosable by a series of molecular and morphological characters and diverged from its Amazonian sister taxon 2.08 million years ago. The estimated time of divergence corresponds to the separation of the Araguaia-Tocantins basin from the Amazon basin. This discovery highlights the immensity of the deficit in our knowledge of Neotropical biodiversity, as well as vulnerability of biodiversity to anthropogenic actions in an increasingly threatened landscape. We anticipate that this study will provide an impetus for the taxonomic and conservation reanalysis of other taxa shared between the Araguaia and Amazon aquatic ecosystems, as well as stimulate historical biogeographical analyses of the two basins.

Toxicity assessment of aqueous extracts of ash from forest fires

Abstract: Wildfires can cause immediate and drastic impacts on the structure and functioning of ecosystems, and there has been an increasing interest in wildfire effects on water chemistry and aquatic biota. Wildfires are increasingly recognized as a diffuse source of contamination of aquatic ecosystems, through the production of deleterious pyrolytic substances and their subsequent transport, mostly attached to ashes. To study the deleterious effects of the ash-laden runoff from burnt areas on water quality, composite ash samples of ashes were collected immediately after a forest fire and then used to prepare aqueous extracts of ash (AEA). The AEA were analyzed with respect to a large group of chemical elements and the sixteen prioritized polycyclic aromatic hydrocarbons (PAHs). Ca, S, Mg, K and Na were found to be the principal elements in the AEA, while only two low molecular weight PAHs (phenanthrene and naphthalene) were present in quantifiable amounts. In parallel, an ecotoxicological screening of the AEA was performed with four standard aquatic species from different functional groups and trophic levels. The AEA was found to induce a statistically significant decrease in the growth of two primary producers – Pseudokirchneriella subcapitata and Lemna minor – and inhibited the luminescence of the bacteria Vibrio fischeri . By contrast, AEA did not produce a significant immobilization of Daphnia magna suggesting that short-term acute toxicity may be absent at higher trophic levels. Overall, the present results emphasize the role of wildfires as a potential source of diffuse contamination for downstream water bodies, compromising both chemical and ecological conditions. At the same time, this study highlights the need for further research into the complexity of the potentially deleterious ecological effects of wildfires on aquatic communities, with a particular focus on cascading effects along the trophic web.

The Theory of Island Biogeography

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

Systematics And The Origin Of Species

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