|
|
|
|
|
| Fromentin, Jean-marc; Ibanez, F. |
| Chronological series (1949 to 1992) of air temperature, precipitation, atmospheric pressure and wind in different parts of the French coast show evidence of important year-to-year changes, trends and cycles: seven-eight years for temperature, and around three years for precipitation and atmospheric pressure. On the scale of France, it appears that spatial heterogeneity of meteorological factors is smaller than temporal heterogeneity. New methods, such as the cumulative sums method or the envelopes of a variable reveal the interest for ecologists of essaying different numerical approaches. A comparison between climatic series and biological series of a benthic and a pelagic species is described for this purpose. |
| Tipo: Text |
Palavras-chave: METEOROLOGICAL SERIES; BIOLOGICAL SERIES; TRENDS; CYCLES; CHANGES. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00098/20891/18505.pdf |
| |
|
|
| Ibanez, F; Fromentin, Jean-marc. |
| The typology of shapes of series (TSS) aims to gather together species having similar temporal patterns corresponding to different types of ecological behaviour. Each type of change, referred to as the ecological shape, is considered to reflect a particular demographic strategy (sudden pullulation of opportunistic species, fluctuations with environmental changes, etc.). This method which consists in the definition of four shape parameters and a classification among the series, taking into account these shape parameters, does not replace the usual statistical analyses, mainly multivariate ones, but precedes them. Such preliminary information is useful for the choice of the subsequent treatments, avoiding the need to analyse simultaneously species presenting... |
| Tipo: Text |
Palavras-chave: Times series; Ecological shape; Macrobenthic community; English Channel. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20384/18050.pdf |
| |
|
| |
|
|
| Fromentin, Jean-marc; Dauvin, Jean-claude; Ibanez, F; Dewarumez, Jean-marie; Elkaim, B. |
| This study examines whether meso-scale meteorological events, in particular the alternation of cold and mild periods, influenced the structure of four Abi cr alba communities, sampled from 1977 to 1992 on the northwest French coast. We propose a new numerical procedure to describe temporal variations in the structure of each assemblage, using some niche-oriented models recently developed by Tokeshi (1993). The description of the temporal changes in the structure of each community was summarized into a 2D-plot of an ordination, performed on observed and simulated patterns. Results showed that important changes occurred in these four assemblages, which were not directly related to the meso-scale climatic events, but mainly to the local environmental factors... |
| Tipo: Text |
Palavras-chave: Macrobenthos community structure species abundance model long-term survey English Channel; North Sea. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20407/18074.pdf |
| |
|
| |
|
|
| Planque, Benjamin; Ibanez, F. |
| Year-to-year changes in abundance of the copepod Calanus finmarchicus in the North Atlantic are studied by means of the Continuous Plankton Recorder (CPR). Using data collected during the years 1962 to 1974, the spatial heterogeneity of long-term trends is studied by numerical analysis: Mantel test, Mantel correlogram, and spatio-temporal clustering. Results reveal that (1) interannual changes of C. finmarchicus abundance are spatially autocorrelated; (2) the spatial structures have a radius varying between 400 and 1100 km; and (3) there is a high variability in the annual changes observed between the different zones detected by clustering. These results show that observations made in the Northeast Atlantic cannot be extrapolated to the whole North... |
| Tipo: Text |
Palavras-chave: North Atlantic; Calanus finmarchicus; Long-term changes; Space-time interactions; Continuous Plankton Recorder. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20388/18055.pdf |
| |
|
| |
|
|
| Baussant, T; Ibanez, F; Dallot, S; Etienne, M. |
| Between March and June 1988, a series of diurnal acoustic records was carried out using a 50 kHz echosounder on a transect crossing the density front of the Ligurian Sea, off Villefranche-sur-Mer (Mediterranean Sea). The depth, thickness and pattern of the sound scattering layers were studied with respect to physical (temperature, salinity and density) and biological (chlorophyll a) measurements made along the acoustic transect. Seasonal differences were observed. A surface scattering layer (SSL), from 0 to 100 m, and a main deep scattering layer (MDSL), located between 250 and 550 m, occurred permanently during the study. In spring, an intermediate scattering layer (ISL), about 50 m thick, occurred between the SSL and the MDSL. The ISL, a permanent... |
| Tipo: Text |
Palavras-chave: SOUND SCATTERING LAYERS; MEDITERRANEAN SEA; LIGURIAN SEA FRONT; CYCLOTHONE-BRAUERI (GONOSTOMATIDAE). |
| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00100/21164/18783.pdf |
| |
|
|
| Dauvin, Jean-claude; Dewarumez, Jean-marie; Elkaim, B; Bernardo, D; Fromentin, Jean-marc; Ibanez, F. |
| Populations of Abra alba (Wood) (Mollusca : Bivalvia) were studied over a fifteen-years period at three sites: the southern part of the North Sea (Gravelines area), the Bay of Seine, and the Bay of Morlaix in the western English Channel. These surveys provide an example of long-term changes in a species considered as ''opportunistic'' and as a ''biological indicator'' of disturbance. A summed cumulated function was used to compare the changes of the Abra alba populations and of mean air temperature in each area. The graph of this function shows the timing and duration of changes. Four or five main periods were identified at each site, with a succession of periods of abundance, stability, and decrease. The abundance periods were separated by ten years in... |
| Tipo: Text |
Palavras-chave: ABRA-ALBA; LONG-TERM CHANGES; CYCLES; CLIMATIC STRESS. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00099/21066/18692.pdf |
| |
|
|
|
