Numerical Ecology with R

Borcard, Daniel; Gillet, François; Legendre, Pierre

doi:10.1007/978-3-319-71404-2

Cited by 976 publications

(1,114 citation statements)

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“…All the tests were performed with the package Rcmdr (2, 1-7) and complementary packages, in the R environment (version 3.1.2) (Borcard et al 2011).…”

Section: Discussionmentioning

confidence: 99%

Antiherbivory defense mechanisms along an environmental gradient in restinga

et al. 2017

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Plant-herbivore interactions have directed the evolution of defense mechanisms in plants, which can vary intraspecifi cally according to environmental quality. Th is study evaluated variation in the production of antiherbivory defenses in plant species distributed along an environmental gradient of restinga. Th e study was performed in Parque Estadual Acaraí, state of Santa Catarina, Brazil. Th ree species of four plant formations with diff erent abiotic conditions were selected for study. Specifi c leaf area; water, nitrogen and carbon content; and presence of phenols, tannins, lignin and alkaloids, were evaluated in leaves of ten plants per species per plant formation. Th e results indicated that Symphyopappus casarettoi possesses Low Nutritional Quality Syndrome, characterized by low specifi c leaf area, presence of secondary metabolites and low nitrogen content. Dodonaea viscosa and Varronia curassavica possess Nutrition and Defense Syndrome, characterized by a balance between nutritional quality (high nitrogen content and lower C:N ratio) and protection (greater thickness of leaves and higher density of trichomes). Th e results did not confi rm the Resource Availability Hypothesis. Th e absence of a pattern in antiherbivory response due to the environmental gradient may indicate that the investment in defense by plants is not unidirectional and that certain morpho-anatomical attributes are typically related to conservation of resources.

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“…All the tests were performed with the package Rcmdr (2, 1-7) and complementary packages, in the R environment (version 3.1.2) (Borcard et al 2011).…”

Section: Discussionmentioning

confidence: 99%

Antiherbivory defense mechanisms along an environmental gradient in restinga

et al. 2017

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“…Second, a partial redundancy analysis (pRDA; Økland 2003) was run using matrix L as response and matrices M, X, and C as explanatory variables. Thus, we considered the gradient from seashore to inland as an explanatory linear spatial structure, and the MEMs as the more complex (patchy) structures (see Borcard et al 2011). A forward selection of variables was run on the explanatory matrices using the ordistep function of the package vegan.…”

Section: Discussionmentioning

confidence: 99%

“…This pRDA determined the bromeliads as an external cause over the other life forms within the forest. In all partitioning procedures, we used the RsquareAdj function in vegan to obtain unbiased estimates of fractions Borcard et al 2011). Lastly, spatial univariate and cross-correlation functions were estimated between bromeliads, fCover and the other life forms using spline (cross) correlograms (Bjørnstad and Falck 2001).…”

Section: Discussionmentioning

confidence: 99%

The role of terrestrial bromeliads in determining the spatial organization of plant life forms in a tropical coastal forest

et al. 2017

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Th e interplay betw een plant-plant interactions and light heterogeneity in the understory of tropical forests has rarely been examined. We aimed to identify the relative importance of the understory light environment and terrestrial bromeliads in explaining the abundance and spatial organization of diff erent plant life forms along a coastal forest gradient from seashore inland in southeastern Brazil. We estimated the abundance of various life forms (herbs, woody plants, bromeliads, climbers, and palms) and the degree of light availability using hemispherical photographs in 165 plots (1 m 2 ) within a 1.75 ha site. We used ordination methods, partial redundancy analysis (pRDA), spatial fi ltering using Moran's eigenvector mapping, and Moran's I splines. Forest cover was highly heterogeneous, but did not explain variation in abundance of life forms. Spatially, bromeliads were negatively associated with woody saplings, herbs and climbing plants at scales between 5-20 m, while the distance to seashore was found to be unrelated to these patterns. Our fi ndings revealed that terrestrial bromeliads play an important role in the spatial organization of various life forms near the forest fl oor. Overall, the presence of terrestrial bromeliads and the plant area index better explained the understory vegetation than forest cover and distance to seashore.

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“…ANOSIM and the Mantel test), and robust enough to violations of the assumptions of normality and homoscedasticity of both data and their residuals (Anderson and Walsh, 2013). To visualize multivariate patterns, we plotted community composition using the first two axes of a three-dimensional non-metric multidimensional scaling (NMDS) based on Euclidean distance, because it preserves the ordering relationships among objects in a small and specified number of axes, and gives a less deformed representation of the distance relationships among objects than other distance methods in the same number of dimensions (Borcard et al, 2011). To assess whether there was a significant relationship (P < 0Á05) between the ordination axis scores (obtained by NMDS) and increased disturbance, we used the 'envfit()' function with 9999 permutations.…”

Section: Community Composition and Association With Disturbed Sitesmentioning

confidence: 99%

Disturbance by an endemic rodent in an arid shrubland is a habitat filter: effects on plant invasion and taxonomical, functional and phylogenetic community structure

Escobedo

Ríos

Salgado‐Luarte

et al. 2017

Ann Bot

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Background and Aims Disturbance often drives plant invasion and may modify community assembly. However, little is known about how these modifications of community patterns occur in terms of taxonomic, functional and phylogenetic structure. This study evaluated in an arid shrubland the influence of disturbance by an endemic rodent on community functional divergence and phylogenetic structure as well as on plant invasion. It was expected that disturbance would operate as a habitat filter favouring exotic species with short life cycles.Methods Sixteen plots were sampled along a disturbance gradient caused by the endemic fossorial rodent Spalacopus cyanus, measuring community parameters and estimating functional divergence for life history traits (functional dispersion index) and the relative contribution to functional divergence of exotic and native species. The phylogenetic signal (Pagel's lambda) and phylogenetic community structure (mean phylogenetic distance and mean nearest taxon phylogenetic distance) were also estimated. The use of a continuous approach to the disturbance gradient allowed the identification of non-linear relationships between disturbance and community parameters.Key Results The relationship between disturbance and both species richness and abundance was positive for exotic species and negative for native species. Disturbance modified community composition, and exotic species were associated with more disturbed sites. Disturbance increased trait convergence, which resulted in phylogenetic clustering because traits showed a significant phylogenetic signal. The relative contribution of exotic species to functional divergence increased, while that of natives decreased, with disturbance. Exotic and native species were not phylogenetically distinct.Conclusions Disturbance by rodents in this arid shrubland constitutes a habitat filter over phylogeny-dependent life history traits, leading to phylogenetic clustering, and drives invasion by favouring species with short life cycles. Results can be explained by high phenotypic and phylogenetic resemblance between exotic and native species. The use of continuous gradients when studying the effects of disturbance on community assembly is advocated.

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Numerical Ecology with R

Cited by 976 publications

References 0 publications

Antiherbivory defense mechanisms along an environmental gradient in restinga

Antiherbivory defense mechanisms along an environmental gradient in restinga

The role of terrestrial bromeliads in determining the spatial organization of plant life forms in a tropical coastal forest

Disturbance by an endemic rodent in an arid shrubland is a habitat filter: effects on plant invasion and taxonomical, functional and phylogenetic community structure

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