Hierarchical Partitioning

Chevan, Albert; Sutherland, M.

doi:10.2307/2684366

Cited by 626 publications

(697 citation statements)

References 0 publications

Supporting

Mentioning

696

Contrasting

Unclassified

Order By: Relevance

“…Therefore, we performed a hierarchical partitioning (HP) analysis to evaluate the independent contribution of each predictor to population indices. Hierarchical partitioning averages the differences in the R 2 values among all combinations of models with and without a given covariate, and returns the independent contribution of each variable to the variance of the dependent variable (Chevan andSutherland 1991, Mac Nally andWalsh 2004). However, this procedure does not produce regression coefficients, nor does it identify a set of models that explains the observed variation in the dependent variables.…”

Section: Methodsmentioning

confidence: 99%

Identification of Putative Wintering Areas and Ecological Determinants of Population Dynamics of Common House-Martin (Delichon urbicum) and Common Swift (Apus apus) Breeding in Northern Italy

Ambrosini¹,

Orioli²,

Massimino³

et al. 2011

ACE

View full text Add to dashboard Cite

ABSTRACT. To identify the causes of population decline in migratory birds, researchers must determine the relative influence of environmental changes on population dynamics while the birds are on breeding grounds, wintering grounds, and en route between the two. This is problematic when the wintering areas of specific populations are unknown. Here, we first identified the putative wintering areas of Common House-Martin (Delichon urbicum) and Common Swift (Apus apus) populations breeding in northern Italy as those areas, within the wintering ranges of these species, where the winter Normalized Difference Vegetation Index (NDVI), which may affect winter survival, best predicted annual variation in population indices observed in the breeding grounds in 1992-2009. In these analyses, we controlled for the potentially confounding effects of rainfall in the breeding grounds during the previous year, which may affect reproductive success; the North Atlantic Oscillation Index (NAO), which may account for climatic conditions faced by birds during migration; and the linear and squared term of year, which account for nonlinear population trends. The areas thus identified ranged from Guinea to Nigeria for the Common House-Martin, and were located in southern Ghana for the Common Swift. We then regressed annual population indices on mean NDVI values in the putative wintering areas and on the other variables, and used Bayesian model averaging (BMA) and hierarchical partitioning (HP) of variance to assess their relative contribution to population dynamics. We re-ran all the analyses using NDVI values at different spatial scales, and consistently found that our population of Common House-Martin was primarily affected by spring rainfall (43%-47.7% explained variance) and NDVI (24%-26.9%), while the Common Swift population was primarily affected by the NDVI (22.7%-34.8%). Although these results must be further validated, currently they are the only hypotheses about the wintering grounds of the Italian populations of these species, as no Common House-Martin and Common Swift ringed in Italy have been recovered in their wintering ranges. RÉSUMÉ. Afin de cerner les causes de déclin des oiseaux migrateurs, les scientifiques doivent déterminer l'influence relative des changements environnementaux sur la dynamique des populations, tant sur les aires de reproduction et d'hivernage que sur les haltes migratoires. Cette démarche est particulièrement problématique lorsque les aires d'hivernage de populations spécifiques sont inconnues. Dans la présente étude, nous avons d'abord déterminé les aires d'hivernage présumées des populations d'Hirondelle de fenêtre (Delichon urbicum) et de Martinet noir (Apus apus) qui se reproduisent dans le nord de l'Italie; ces aires présumées correspondent aux endroits, dans l'ensemble de l'aire d'hivernage de ces espèces, où l'indice de végétation par différence normalisée (IVDN) -qui affecte peut-être la survie hivernaleexpliquait le mieux la variation annuelle des indices de population observés sur les aires...

show abstract

Section: Methodsmentioning

confidence: 99%

Identification of Putative Wintering Areas and Ecological Determinants of Population Dynamics of Common House-Martin (Delichon urbicum) and Common Swift (Apus apus) Breeding in Northern Italy

Ambrosini¹,

Orioli²,

Massimino³

et al. 2011

ACE

View full text Add to dashboard Cite

show abstract

“…In all analyses, vegetation structures (shrub cover, tree density) were treated as continuous variables. We tested for pairwise differences among treatment classes using general linear hypothesis tests (Searle 1971) in the 'MULTCOMP' package (Hothorn et al 2007) (Chevan & Sutherland 1991). We used generalized linear mixed models (GLMM) with binomial error structure (Broströ m 2007) to test the hypothesis that warbler settlement/absence depended on our treatments over repeated visits.…”

Section: Methodsmentioning

confidence: 99%

Social information trumps vegetation structure in breeding-site selection by a migrant songbird

et al. 2008

View full text Add to dashboard Cite

To maximize fitness, organisms must assess and select suitable habitat. Early research studying birds suggested that organisms consider primarily vegetation structural cues in their habitat choices. We show that experimental exposure to singing in the post-breeding period provides a social cue that is used for habitat selection the following year by a migrant songbird, the black-throated blue warbler (Dendroica caerulescens). Our experimental social cues coerced individuals to adopt territories in areas of very poor habitat quality where individuals typically do not occur. This indicates that social information can override typical associations with vegetation structure. We demonstrate that a strong settlement response was elicited because post-breeding song at a site is highly correlated with reproductive success. These results constitute a previously undocumented, but highly parsimonious mechanism for the inadvertent transfer of reproductive (public) information from successful breeders to dispersers. We hypothesize that post-breeding song is a pervasive and reliable cue for species that communicate vocally, inhabit temporally autocorrelated environments, produce young asynchronously and/or abandon territories after reproductive failure.

show abstract

“…The SE values allow us to determine the precision of the estimated model and variables; therefore, if the SE value is two times greater than the estimated parameter, then we can conclude that this parameter is not a good estimator of the response variable (Anderson, 2008). In order to evaluate the relative importance of each variable, we established the weight of each explanatory variable using the function to calculate relative importance metrics for linear models (calc.relimp) with R^2 contribution averaged over orderings among regressors (Chevan and Sutherland, 1991). The statistical analyses were done using the R statistic program (R Development Core Team R, 2013).…”

Section: Methodsmentioning

confidence: 99%

Plant structure predicts leaf litter capture in the tropical montane bromeliad Tillandsia turneri

Bautista

Varón

2016

Braz. J. Biol.

View full text Add to dashboard Cite

Leaves intercepted by bromeliads become an important energy and matter resource for invertebrate communities, bacteria, fungi, and the plant itself. The relationship between bromeliad structure, defined as its size and complexity, and accumulated leaf litter was studied in 55 bromeliads of Tillandsia turneri through multiple regression and the Akaike information criterion. Leaf litter accumulation in bromeliads was best explained by size and complexity variables such as plant cover, sheath length, and leaf number. In conclusion, plant structure determines the amount of litter that enters bromeliads, and changes in its structure could affect important processes within ecosystem functioning or species richness.Keywords: leaf litter, Bromeliaceae, plant structure, tropical montane forest.A estrutura da planta determina a folhagem interceptada pela bromelia Tillandsiaturneri ResumoAs folhagens interceptadas pelas bromélias é um importante recurso para a comunidade de invertebrados, bactérias, fungos e para a própria planta. Estudou-se a relação entre a estrutura de 55 bromélias de Tillandsia tumeri, definida como o tamanho, a complexidade da planta, a folhagem acumulada por meio de regressão múltipla e o critério de informação de Akaike. Encontrou-se que as variáveis de tamanho, cobertura, comprimento da bainha e a variável de complexidade do número de folhas explicam a acumulação de folhas nas bromélias. Em conclusão, a estrutura do planta determina a quantidade de folhas armazenada na bromélia e os câmbios da estrutura da bromélia poderiam afetar importantes processos de funcionamento do ecossistema ou a riqueza de espécies.Palavras-chave: folhagens, Bromeliaceae, estrutura do planta, floresta tropical montana.

show abstract

Hierarchical Partitioning

Cited by 626 publications

References 0 publications

Identification of Putative Wintering Areas and Ecological Determinants of Population Dynamics of Common House-Martin (Delichon urbicum) and Common Swift (Apus apus) Breeding in Northern Italy

Identification of Putative Wintering Areas and Ecological Determinants of Population Dynamics of Common House-Martin (Delichon urbicum) and Common Swift (Apus apus) Breeding in Northern Italy

Social information trumps vegetation structure in breeding-site selection by a migrant songbird

Plant structure predicts leaf litter capture in the tropical montane bromeliad Tillandsia turneri

Contact Info

Product

Resources

About