El análisis de componentes principales de tablas florísticas de presencia-ausencia como herramienta para análisis de gradientes ambientales. Un estudio de caso en la Quebrada de Vaquerías (Valle Hermoso, Córdoba)
The vegetation of the Quebrada de Vaquerias (Chaquean Phytogeographic Province, Chaco Serrano District) was estudied by Principal Components Analysis on data of 50 stands distributed along a complex environiental gradient. The results show the influence of aspect and altitude on the distribution of the vegetation. The analysis indicate that presence - absence data are more efficient than quantitative data in describing vegelational change in communities with a high 13-diversity. First axis stand scores of the non-centered analysis were highly correlated with site diversity. Axes 2, 3 and 4 of the non- centered analysis were .similar to aces 1, 2, and 3 of the centered procedure. An ANOVA showed that (a) the first of these axes is strongly associated with aspect, (b) the second floristic axis is strongly associated with the altitude vahies on llte S-SE slopes; and (c) the third florislic axis is associated with attitudinal variation on the N-NW slopes. For the last two cases, a .stepwise multiple regression analysis showed that che foro of the response is linear. Die analysis of the species-loading showed that inosl species with high loading, coincide with the diagnostic species singled by a phylosociological tabular analysis. The properties of principal components analysis when applied to presence-absence data are discussed from these results.
| Main Authors: | , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Asociación Argentina de Ecología
1991
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| Online Access: | https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/1750 |
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| Summary: | The vegetation of the Quebrada de Vaquerias (Chaquean Phytogeographic Province, Chaco Serrano District) was estudied by Principal Components Analysis on data of 50 stands distributed along a complex environiental gradient. The results show the influence of aspect and altitude on the distribution of the vegetation. The analysis indicate that presence - absence data are more efficient than quantitative data in describing vegelational change in communities with a high 13-diversity. First axis stand scores of the non-centered analysis were highly correlated with site diversity. Axes 2, 3 and 4 of the non- centered analysis were .similar to aces 1, 2, and 3 of the centered procedure. An ANOVA showed that (a) the first of these axes is strongly associated with aspect, (b) the second floristic axis is strongly associated with the altitude vahies on llte S-SE slopes; and (c) the third florislic axis is associated with attitudinal variation on the N-NW slopes. For the last two cases, a .stepwise multiple regression analysis showed that che foro of the response is linear. Die analysis of the species-loading showed that inosl species with high loading, coincide with the diagnostic species singled by a phylosociological tabular analysis. The properties of principal components analysis when applied to presence-absence data are discussed from these results. |
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