An Alternative to Correspondence Analysis Using Hellinger Distance.

Rao, C. R.

doi:10.21236/ada325255

Cited by 135 publications

(153 citation statements)

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“…A multivariate regression tree (MRT) followed the approach described by Borcard et al (2011) and Lindfield et al (2016) using the R package mvpart (De'Ath, 2007) with MRTs primarily acting as predictive (vs. explanatory) models. Prior to MRT generation, relative abundance data were first Hellinger-transformed, which is an approach well-suited for species abundance datasets, granting lower weights to rare species (Legendre and Gallagher, 2001) and multiple zero counts (Rao, 1995). Optimal tree size was generated from 100 model runs, with the model selection output based on the highest cross-validated predictive accuracy.…”

Section: Habitat and Environmental Linkagesmentioning

confidence: 99%

Mesophotic Depth Gradients Impact Reef Fish Assemblage Composition and Functional Group Partitioning in the Main Hawaiian Islands

2017

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Mesophotic coral ecosystem (MCE) research has increased considerably in recent years, as MCEs may provide partial insulation from the effects of climate change, localized anthropogenic stressors, and may dampen fishing pressures for target species depleted in shallower waters. However, few studies have examined coral reef fish assemblages and functional groups across shallow water to mesophotic depth gradients. In the Main Hawaiian Islands, we investigated coral reef fish communities between 0 and 100 m using baited remote underwater stereo-video. While significant community shifts were detected when transitioning from shallow water to mesophotic depths, relative abundance and species richness remained highest between 0 and 30 m. Mobile invertivores and generalist macropiscivores were exceptions, recording higher abundance and richness values in deeper waters. Depth, habitat complexity, and percent cover of unconsolidated sediment and macroalgae were the main reef fish community drivers in multivariate regression and distance-based linear models. Finally, several target species were more abundant and/or larger in deeper waters, suggesting stock assessment and resource management strategies are incomplete without the incorporation of mesophotic portions of stocks.

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Section: Habitat and Environmental Linkagesmentioning

confidence: 99%

Mesophotic Depth Gradients Impact Reef Fish Assemblage Composition and Functional Group Partitioning in the Main Hawaiian Islands

2017

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“…Otherwise, the difference in species composition between the years would have confounded further multivariate analyses. To prevent biases introduced by a large number of zero cover occurrences or by a small number of very high cover values, the cover values in the species data matrix were transformed using the Hellinger distance [30], which is the square root of the row totals divided by the row mean values. This distance measure showed good performance for abundance data throughout different multivariate ordination methods, especially for those relying on a linear gradient structure [31].…”

Section: Vegetation Samplingmentioning

confidence: 99%

Mapping Bush Encroaching Species by Seasonal Differences in Hyperspectral Imagery

et al. 2010

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Bush encroachment is a form of land degradation prominent worldwide, but particularly present in semi-arid areas. In this study, we mapped the spatial distribution of the two encroacher species, Acacia mellifera and Acacia reficiens, in Central Namibia, based on their different phenological behavior. We used constrained principal curves to extract a one dimensional gradient of phenological change from two hyperspectral images taken in different seasons. Field measurements of species composition and cover values were statistically related to bi-temporal differences in hyperspectral vegetation indices in a direct gradient analysis. The extracted gradient reflected the relationship between species composition and cover values, and the phenological pattern as captured by the image data. Cover values of four dominant plant species were mapped and species responses along the phenological gradient were interpreted.

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“…In order to reduce the influence of less abundant species, all the species with less than 1% accumulated occurrence were excluded from the abundance matrix (SEDBERRY;CARTE, 1993;FEYRER;HEALEY, 2003). The reduced matrix data were then submitted to an F max test and transformed into Ln (x + 1) form, before further transformation through the Hellinger´s distance (RAO, 1995;LEGENDRE;LEGENDRE, 1998).…”

Section: Data Collectionmentioning

confidence: 99%

Spatial and temporal distribution of fish in Palmas bay, Ubatuba, Brazil

2010

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A B S T R A C TThe aim of this study was to analyze the distribution and abundance of the fish fauna of Palmas bay on Anchieta Island in southeastern Brazil. Specimens were caught in the summer and winter of 1992, using an otter trawl at three locations in the bay. The specimens were caught in both the nighttime and daytime. Data on the water temperature and salinity were recorded for the characterization of the predominant water mass in the region, and sediment samples were taken for granulometric analysis. A total of 7 656 specimens (79 species), with a total weight of approximately 300 kg, were recorded. The most abundant species were Eucinostomus argenteus, Ctenosciaena gracilicirrhus, Haemulon steindachneri, Eucinostomus gula and Diapterus rhombeus, which together accounted for more than 73% of the sample. In general, the ecological indices showed no differences in the composition of species for the abiotic variables analyzed. The multivariate analysis showed that the variations in the distribution of the fish fauna were mainly associated with intra-annual differences in temperature and salinity, resulting from the presence of South Atlantic Central Water (SACW) in the area during the summer. The analysis also showed an association with the type of bottom and a lesser association with respect to the night/day periods. R E S U M OEste estudo teve como objetivo analisar a composição e a abundância da fauna de peixes provenientes da enseada Palmas em Ubatuba, costa sudeste do Brasil. Os espécimes foram obtidos no verão e no inverno de 1992, utilizando-se uma rede de arrasto de fundo em três locais da enseada. Os arrastos foram realizados no período noturno e no período diurno. Foram obtidos dados de temperatura e salinidade da água para caracterização da massa de água predominante na região e amostras do sedimento para análise granulométrica. Foram capturadas 79 espécies de Actinopterygii, representadas por 7 656 indivíduos com peso total aproximado de 300 kg. As espécies mais abundantes foram Eucinostomus argenteus, Ctenosciaena gracilicirrhus, Haemulon steindachneri, Eucinostomus gula e Diapterus rhombeus e representaram mais de 73% da amostra. Os índices ecológicos utilizados, de uma maneira geral, não mostraram diferenças na composição das espécies quanto às variáveis abióticas analisadas. A análise multivariada empregada mostrou que as variações encontradas na distribuição da fauna de peixes foram associadas principalmente às diferenças intraanuais de temperatura e salinidade, relacionadas à presença da Água Central do Atlântico Sul no verão na área de estudo. A análise também mostrou uma associação em relação ao tipo de fundo e uma menor associação em relação aos períodos do ciclo noite/dia.

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An Alternative to Correspondence Analysis Using Hellinger Distance.

Cited by 135 publications

References 0 publications

Mesophotic Depth Gradients Impact Reef Fish Assemblage Composition and Functional Group Partitioning in the Main Hawaiian Islands

Mesophotic Depth Gradients Impact Reef Fish Assemblage Composition and Functional Group Partitioning in the Main Hawaiian Islands

Mapping Bush Encroaching Species by Seasonal Differences in Hyperspectral Imagery

Spatial and temporal distribution of fish in Palmas bay, Ubatuba, Brazil

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