Consulta: creatorFacets:"Legendre, P"
Registros recuperados: 6
Data/hora: 10/06/2024 11:04:42

Physical and chemical factors influencing species distributions on hydrothermal sulfide edifices of the Juan de Fuca Ridge, northeast Pacific
Provedor de dados: 5
Autores: Sarrazin, Jozee; Juniper, Sk; Massoth, G; Legendre, P.
This study examines relationships between hydrothermal vent species and their surrounding physical and chemical environment on 2 high-temperature sulfide edifices of the Juan de Fuca Ridge (northeast Pacific). Video imagery and in situ temperature and chemical information were acquired during 2 remotely operated vehicle (ROV) dive programs in 1993 and 1995, for a total of 78 scans. Statistical analyses of environmental and faunal data reveal a heterogeneous distribution (cor respondence analyses) of hydrothermal species and demonstrate a significant influence of local physical and chemical conditions on species distributions (canonical correspondence analyses). Results confirm the importance of hydrogen sulfide to the distribution of vent species as well...
Tipo: Text
Palavras-chave: Hydrothermal vent ecology; Physical and chemical factors; In situ measurements; Habitat characterization; Species distribution; Sulfide edifice; Statistical analyses; Fluid flow; Substratum types; Mosaic habitat.
Ano: 1999
URL: http://archimer.ifremer.fr/doc/00280/39113/37666.pdf

How do coral reef Gastropods feel about nuclear blasts? A long-term study of the effects of man-made perturbations
Provedor de dados: 5
Autores: Lanctot, Jl; Legendre, P; Salvat, B.
The resistance to perturbations of reef-dwelling gastropod assemblages was studied on the seaward reefs of Fangataufa atoll (French Polynesia) after their exposure to atmospheric nuclear tests, a major man-made perturbation. We focused on two important aspects: (1) the temporal evolution of the densities of the most important species before and after the tests, and (2) the temporal evolution of the spatial structure of the assemblages. Three transects, crossing several geomorphological zones, were established on the seaward reefs of the atoll. Each transect was sampled at irregular time intervals during a twenty-year period. Several univariate and multivariate methods were used to study (1) the temporal fluctuations in species abundances and ranks, and (2)...
Tipo: Text
Palavras-chave: Atmospheric nuclear tests; Clustering; Coral reefs; Gastropods; Perturbation.
Ano: 1997
URL: http://archimer.ifremer.fr/doc/00093/20394/18061.pdf

Le programme Écothau : théorie écologique et base de la modélisation
Provedor de dados: 5
Autores: Amanieu, M; Legendre, P; Troussellier, Marc; Frisoni, Gf.
Tipo: Text
Ano: 1989
URL: http://archimer.ifremer.fr/doc/00106/21747/19320.pdf

Organisation spatiale et modélisation écologique d'un peuplement phytoplanctonique de lagune (étang de Thau, France)
Provedor de dados: 5
Autores: Jarry, V; Frisoni, Gf; Legendre, P.
A systematic sampling of twenty stations was conducted over four periods within a year (June 1986, October 1986, February 1987, and May 1987) in Thau lagoon. Multivariate analyses (clustering, and principal coordinate analysis) were carried out on phytoplankton species counts. These analyses allowed homogenous areas within the lagoon to be identified and permitted the characterization of these areas in terms of the marine or continental origins of their phytoplankton taxa. The results show the relative importance of each kind of input (marine, continental), and contrast the punctual influence of the continental inputs against the more global effects of the sea. The conclusions drawn from the taxonomic portion of the study were confirmed by statistical...
Tipo: Text
Palavras-chave: Phytoplankton; Populations; Chlorophyll pigments; Ecological modelling; Mediterranean lagoon; PHYTOPLANKTON; POPULATIONS; CHLOROPHYLL PIGMENTS; ECOLOGICAL MODELING; MEDITERRANEAN LAGOON.
Ano: 1991
URL: http://archimer.ifremer.fr/doc/00323/43397/43105.pdf

Comparison of surfaces
Provedor de dados: 5
Autores: Legendre, P; Mcardle, Bh.
Values of a variable observed over a delimited geographic area are called a ''surface''. The problem we investigate is how to compare measures of the same area observed at two or more Sampling times. It is important to recognise that two different null hypotheses can be tested about the surface. The first is that the corresponding values in the surfaces differ only because of measurement or sampling error. The second is that the underlying process that generated the surfaces is the same. In the first case, the surfaces should have the same shape and values, while in the second case the surfaces might have different values, but if they still have the same means, variances and autocorrelation structures, the null hypothesis cannot be rejected. To prove the...
Tipo: Text
Palavras-chave: Analysis of variance; Comparison of surfaces; Log-linear model; Sampling strategy; Trend surface analysis.
Ano: 1997
URL: http://archimer.ifremer.fr/doc/00093/20397/18064.pdf

Variation interannuelle des peuplements récifaux du récif-barrière de Tiahura (île de Moorea, Polynésie française)
Provedor de dados: 5
Autores: Augustin, D; Galzin, R; Legendre, P; Salvat, B.
The interannual variability of the five dominant coral reef communities of the French Polynesia seascape (algae, corals, echinoderms, molluscs and fishes) was studied from 1990 to 1994 in the Tiahura sector of Moorea Island. Qualitative (species richness) and quantitative (cover percentage or density, depending on the type of community) stability is shown for benthic communities (algae, corals, echinoderms and molluscs), except for the macroalgae group and for bivalve species Tridacna maxima. In contrast, the fish community shows in its abundance a significant interannual variability characterized by a recruitment peak in 1991 and gradual and stochastic changes of densities for a few species. The bleaching events (in 1991 and 1994) and the cyclone Wasa...
Tipo: Text
Ano: 1997
URL: http://archimer.ifremer.fr/doc/00093/20432/18099.pdf