Generalized discriminant analysis based on distances

Anderson, Marti J.; Robinson, John

doi:10.1111/1467-842x.00285

Cited by 644 publications

(390 citation statements)

References 22 publications

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“…In case of significant 'shelf-slope Â year' interactions, pair-wise tests of 'year' within 'shelf-slope' were performed to investigate the difference between years at shelf or slope location. Because of the restricted number of possible permutations in 'shelf-slope' effect and pair-wise tests, p-values were obtained from Monte Carlo samplings (Anderson and Robinson, 2003). A Euclidean distance-based resemblance matrix was used and probability values were obtained by permutation (n = 10 4 ).…”

Section: Statistical Treatment Of Datamentioning

confidence: 99%

Phytoplankton community dynamics during late spring coccolithophore blooms at the continental margin of the Celtic Sea (North East Atlantic, 2006–2008)

Oostende

Harlay

Vanelslander

et al. 2012

Progress in Oceanography

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a b s t r a c tWe determined the spatial and temporal dynamics of major phytoplankton groups in relation to biogeochemical and physical variables during the late spring coccolithophore blooms (May-June) along and across the continental margin in the Celtic Sea (2006Sea ( -2008. Photosynthetic biomass (chl a) of the dominant plankton groups was determined by CHEMTAX analysis of chromatographic (HPLC) pigment signatures.Phytoplankton standing stock biomass varied substantially between and during the campaigns (areal chl a [mg chl a m À2 ] in June 2006: 63.8 ± 26.5, May 2007: 27.9 ± 8.4, and May 2008: 41.3 ± 21.8), reflecting the different prevailing conditions of weather, irradiance, and sea surface temperature between the campaigns. Coccolithophores, represented mainly by Emiliania huxleyi, and diatoms were the dominant phytoplankton groups, with a maximal contribution of, respectively, 72% and 89% of the total chl a. Prasinophytes, dinoflagellates, and chrysophytes often co-occurred during coccolithophorid blooms, while diatoms dominated the phytoplankton biomass independently of the biomass of other groups. The location of the stations on the shelf or on the slope side of the continental margin did not influence the biomass and the composition of the phytoplankton community despite significantly stronger water column stratification and lower nutrient concentrations on the shelf. The alternation between diatom and coccolithophorid blooms of similar biomass, following the mostly diatom-dominated main spring bloom, was partly driven by changes in nutrient stoichiometry (N:P and dSi:N). High concentrations of transparent exopolymer particles (TEP) were associated with stratified, coccolithophore-rich water masses, which probably originated from the slope of the continental margin and warmed during advection onto the shelf. Although we did not determine the proportion of export production attributed to phytoplankton groups, the abundance of coccolithophores, together with TEP and coccoliths may affect the carbon export efficiency through increased sinking rates of particles formed by aggregation of TEP and coccoliths.

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Section: Statistical Treatment Of Datamentioning

confidence: 99%

Phytoplankton community dynamics during late spring coccolithophore blooms at the continental margin of the Celtic Sea (North East Atlantic, 2006–2008)

Oostende

Harlay

Vanelslander

et al. 2012

Progress in Oceanography

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“…PERMANOVA partitions the total sum of squares based on the full experimental design (given below), and calculates a distance based pseudo-F statistic for each term in the model, based on the expectations of the mean squares. P-values are obtained using a permutation procedure for each term (Anderson et al, 2008), or via Monte Carlo random drawn from an asymptotic permutation distribution if too few permutations are available for a given test (Anderson and Robinson, 2003).…”

Section: Data Analysesmentioning

confidence: 99%

Environmental factors – spatial and temporal variation of chironomid communities in oceanic island streams (Azores archipelago)

Raposeiro

Costa

Hughes

2011

Ann. Limnol. - Int. J. Lim.

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-Freshwater systems on volcanic oceanic islands have very particular characteristics as a result of their geological origins, relatively small size, distances from source areas for colonizers, and distinct catchment morphology. These factors result in freshwater communities that are clearly distinct from continental systems. Chironomid spatial and temporal distribution was investigated in chironomid assemblages at 21 sites across the Azores Archipelago. Results using PERMANOVA, a permutational multivariate analysis of variance, indicated significant longitudinal differences in assemblages but none between islands or over time.Links between hydromorphological and physicochemical variables and the community assemblage were assessed using DISTLM, a linear model for distance-based multivariate analysis. The percentage of variation explained by hydromorphological factors (31%) was slightly higher than that explained by physicochemical (28%) factors. Descriptors of land use (forest area, scrub area, natural area of catchment) and stream slope were found to be the best environmental predictors of chironomid assemblages in Azores. Physicochemical variables such as temperature, pH, nitrite, iron and conductivity were the principal drivers of change in chironomid composition in stream locations. Headwater sites, characterized by lower temperature, acid to neutral pH values, low conductivity, nutrient and metal concentrations were dominated by Rheocricotopus atripes. Mid-section sites, located in agricultural areas were dominated by Thienemanniella clavicornis. Urbanized lower reaches were characterized by higher temperature, pH, conductivity and nutrient levels and were dominated by Cricotopus sp. These results give essential information that allows us to predict the response of different chironomid species to hydromorphological and physicochemical gradients across the archipelago's streams contributing providing the basis for the development of tools for the implementation of the Water Frame Directive.

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“…Pair-wise tests between stations obtained through the PERMANOVA analysis on one-way experimental design are reported in Table 3. As the number of unique values under permutations was very low, P-values were obtained using Monte Carlo samples from the asymptotic permutation distribution (Anderson and Robinson, 2003). Benthic species richness and diversity showed variability between stations.…”

Section: Resultsmentioning

confidence: 99%

The ecological status of Karavasta Lagoon (Albania): Closing the stable door before the horse has bolted?

Cristina

Tessari

Rossi

et al. 2010

Marine Environmental Research

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Karavasta is the widest and most important lagoon in Albania. This study aimed to assess the ecological quality status of the lagoon, acquire knowledge of a natural environment which might be exploited for aquaculture, and give management hints on the basis of anthropogenic impact and ecological conditions. A sampling campaign was carried out in 2008: at six stations, benthic fauna, water and sediment parameters were considered. Statistical analyses were carried out through multivariate procedures (PCA, classification clustering, SIMPER, RDA, DISTLM, PERMANOVA). Ecological quality was assessed through the AZTI Marine Biotic Index (AMBI), the multivariate AMBI (M-AMBI) and the Benthic Index based on Taxonomic Sufficiency (BITS). Sediment characteristics (percent organic matter, %OM; redox potential discontinuity layer depth, RPDL; particle size composition) and salinity represented contributory influences on lagoon communities. It was possible to distinguish and characterise a confined area, and benthic communities, from a marine-influenced area and its biota. The number of species was quite low when compared with other open Adriatic lagoons. ACCEPTED MANUSCRIPT 2The M-AMBI and BITS classifications gave quite similar results, which seemed consistent with the ecological conditions of the lagoon, that is a distinction in the ecological quality between the seaward and landward stations, with higher ecological quality (EcoQ) at the seaward stations. Given the pressures and the ecological condition of Karavasta, an intensification of aquaculture activities must be considered with caution, since the lagoon seems at significant risk of serious hypereutrophication. This situation is made worse by the limited water exchange with the marine environment due to the irregular dredging of the communication channels.

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Generalized discriminant analysis based on distances

Cited by 644 publications

References 22 publications

Phytoplankton community dynamics during late spring coccolithophore blooms at the continental margin of the Celtic Sea (North East Atlantic, 2006–2008)

Phytoplankton community dynamics during late spring coccolithophore blooms at the continental margin of the Celtic Sea (North East Atlantic, 2006–2008)

Environmental factors – spatial and temporal variation of chironomid communities in oceanic island streams (Azores archipelago)

The ecological status of Karavasta Lagoon (Albania): Closing the stable door before the horse has bolted?

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