Keystone Species
Mostrando 1-12 de 15 artigos, teses e dissertações.
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1. Nectar ecology of the endemic epiphytic hummingbird-pollinated bromeliad Vriesea altodaserrae: secretion dynamics and pollinator visitation pattern
ABSTRACT Hummingbirds are the main pollinators of most bromeliad species, whose nectar traits usually respond to the selective pressures imposed by pollinators. Considering the specialization of hummingbird-pollinated bromeliads, we expect a close relationship between nectar ecophysiology and the needs of the main pollinators. In this sense, we studied the n
Acta Bot. Bras.. Publicado em: 15/09/2018
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2. An overview of malaria transmission from the perspective of Amazon Anopheles vectors
In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been
Mem. Inst. Oswaldo Cruz. Publicado em: 13/02/2015
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3. Biodiversity, distribution and abundance of shrimps Penaeoidea and Caridea communities in a region the vicinity of upwelling in Southeastern of Brazil
This study evaluated the spatial-temporal distribution of the abundance of Caridean and Penaeid shrimps during the period of two years in the coastal region of Macaé, state of Rio de Janeiro, southeastern Brazil, using ecological indices (Shannon-Wiener diversity and Pielou's equitability). Monthly samples were carried out from March 2008 to February 2010 d
Nauplius. Publicado em: 2014-06
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4. Behavior of tamarins, tanagers and manakins foraging in a strangler fig (Ficus sp.) in Suriname, South America: implications for seed dispersal
The behavior of foragers can directly affect the dispersal of seeds. Strangler figs are keystone resources throughout the tropics and are important resources for both primates and birds. We examined the foraging behavior of golden-handed tamarins and four bird species in a strangler fig to see how these behaviors might affect the dispersal of fig seeds. Tama
Biota Neotropica. Publicado em: 2009-09
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5. Frugivory of Ficus (Moraceae) by birds in areas with different levels of forest fragmentation in São Paulo State / Frugivoria de Ficus (Moraceae) por aves em paisagens com diferentes níveis de fragmentação florestal no Estado de São Paulo
Ficus (Moraceae) é o gênero mais importante para animais frugívoros nas florestas tropicais, considerado um recurso-chave durante períodos de escassez de frutos. Esses animais dispersam suas sementes e contribuem para a manutenção das populações de figueiras. A perda de hábitat e a fragmentação da paisagem podem afetar a sobrevivência de populaç
Publicado em: 2009
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6. Double keystone bird in a keystone species complex.
Species in a Colorado subalpine ecosystem show subtle interdependences. Red-naped sapsuckers play two distinct keystone roles. They excavate nest cavities in fungus-infected aspens that are required as nest sites by two species of swallows, and they drill sap wells into willows that provide abundant nourishment for themselves, hummingbirds, orange-crowned wa
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7. Keystone species and food webs
Different species are of different importance in maintaining ecosystem functions in natural communities. Quantitative approaches are needed to identify unusually important or influential, ‘keystone’ species particularly for conservation purposes. Since the importance of some species may largely be the consequence of their rich interaction structure, one
The Royal Society.
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8. Large extinctions in an evolutionary model: The role of innovation and keystone species
The causes of major and rapid transitions observed in biological macroevolution as well as in the evolution of social systems are a subject of much debate. Here we identify the proximate causes of crashes and recoveries that arise dynamically in a model system in which populations of (molecular) species coevolve with their network of chemical interactions. C
The National Academy of Sciences.
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9. Complexity and fragility in ecological networks.
A detailed analysis of three species-rich ecosystem food webs has shown that they display skewed distributions of connections. Such graphs of interaction are, in fact, shared by a number of biological and technological networks, which have been shown to display a very high homeostasis against random removals of nodes. Here, we analyse the responses of these
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10. Umbrellas and flagships: Efficient conservation surrogates or expensive mistakes?
The use of umbrella and flagship species as surrogates for regional biota whose spatial distributions are poorly known is a popular conservation strategy. Yet many assumptions underlying the choice of surrogate species remain untested. By using biodiversity databases containing spatial incidence data for species of concern for (i) the southern California coa
The National Academy of Sciences.
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11. A model for the emergence of cooperation, interdependence, and structure in evolving networks
Evolution produces complex and structured networks of interacting components in chemical, biological, and social systems. We describe a simple mathematical model for the evolution of an idealized chemical system to study how a network of cooperative molecular species arises and evolves to become more complex and structured. The network is modeled by a d
The National Academy of Sciences.
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12. Chaotic flow: The physics of species coexistence
Hydrodynamical phenomena play a keystone role in the population dynamics of passively advected species such as phytoplankton and replicating macromolecules. Recent developments in the field of chaotic advection in hydrodynamical flows encourage us to revisit the population dynamics of species competing for the same resource in an open aquatic system. If
The National Academy of Sciences.