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| Duplisea, Daniel; Blanchard, Fabian. |
| We examined the dynamics of fish species and how they relate to species assemblage coherence in the heavily exploited Georges Bank fish community. Coherence is defined as reduced temporal variability of total assemblage biomass. We assumed that a higher degree of compensation hence coherence occurs within competitively coupled species assemblages; therefore, fisheries may directly alter the dynamics of certain targeted species sizes but assemblage structure will be relatively more stable owing to compensatory interactions. Species-sizes were grouped, based on negative covariance coupling in biomass time series from survey data. Assemblages representing benthic feeders were clearly identified by this method; furthermore, the most heavily exploited... |
| Tipo: Text |
Palavras-chave: Diversity stability; Species replacement; Energy flow; Emergent property; Thermodynamics; Goal function. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-806.pdf |
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| Corrêa,Michele M.; Bieber,Ana G.D.; Wirth,Rainer; Leal,Inara R.. |
| Atta cephalotes (L.) presents a wide distribution in the Neotropical region. In Brazil, this species is disjunctly distributed in the Amazon region and in the states of Maranhão, Pernambuco and southern Bahia, all of which belong to Northeast Region. Here we report on a survey of Atta colonies in 42 remnants of the Atlantic rainforest in Alagoas and Pernambuco. Our results include new records of A. cephalotes in the state of Alagoas and thereby extend the known distribution area of its southern populations in Northeast Brazil. In addition, the species was strongly associated with well-conserved forest remnants, indicating that it is highly sensitive to disturbance. We suggest that, in the fragmented scenario of the northeastern Atlantic forest, A.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Brazilian Atlantic Forest; Disjunct distribution; Leaf-cutting ant; New record; Species replacement; Disturbance sensitive taxon. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-566X2005000400023 |
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| NOE,LAURA; ABRIL,ADRIANA. |
| We tested if the microbial functional redundancy concept (theory relating changes in ecosystem functioning by species loss) apply for changes in the ammonium-oxidizing community (nitrifier bacteria) due to: a) grazing disturbance, b) seasonal variations (dry season vs. wet season), c) habitat type (soil vs. organic residues), and d) ecological conditions (two eco-regions), in an arid region of central-western of Argentina. We determined: a) abundance of culturable nitrifier bacteria, b) nitrification activity and efficiency, and c) nitrifier community genetic structure by PCR-DGGE (richness and similarity index). Grazing did not change the nitrifier abundance, activity and richness, while seasonally and eco-region effects were scarce. Contrarily, the... |
| Tipo: Journal article |
Palavras-chave: Arid Chaco; Monte desert; PCR-DGGE; Similarity index; Species replacement. |
| Ano: 2013 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2013000300009 |
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