scholarly journals Using functional traits to predict species growth trajectories, and cross‐validation to evaluate these models for ecological prediction

2019 ◽  
Author(s):  
Freya M. Thomas ◽  
Jian D. L. Yen ◽  
Peter A. Vesk
Keyword(s):  
Functional Traits ◽  
Cross Validation ◽  
Growth Trajectories

scholarly journals Soil variation response is mediated by growth trajectories rather than functional traits in a widespread pioneer Neotropical tree

2018 ◽  
Author(s):  
Sébastien Levionnois ◽  
Niklas Tysklind ◽  
Eric Nicolini ◽  
Bruno Ferry ◽  
Valérie Troispoux ◽  
...  
Keyword(s):  
Functional Traits ◽  
Soil Types ◽  
Tree Level ◽  
Growth Trajectories ◽  
List Type ◽  
Residual Water ◽  
Growth Strategies ◽  
Soil Response ◽  
Neotropical Tree ◽  
Adult Trees

AbstractTrait-environment relationships have been described at the community level across tree species. However, whether interspecific trait-environment relationships are consistent at the intraspecific level is yet unknown. Moreover, we do not know how consistent is the response between organ vs. whole-tree level.We examined phenotypic variability for 16 functional leaf (dimensions, nutrient, chlorophyll) and wood traits (density) across two soil types, Ferralitic Soil (FS) vs. White Sands (WS), on two sites for 70 adult trees of Cecropia obtusa Trécul (Urticaceae) in French Guiana. Cecropia is a widespread pioneer Neotropical genus that generally dominates early successional forest stages. To understand how soil types impact resource-use through the processes of growth and branching, we examined the architectural development with a retrospective analysis of growth trajectories. We expect soil types to affect both, functional traits in relation to resource acquisition strategy as already described at the interspecific level, and growth strategies due to resource limitations with reduced growth on poor soils.Functional traits were not involved in the soil response, as only two traits-leaf residual water content and K content-showed significant differences across soil types. Soil effects were stronger on growth trajectories, with WS trees having the slowest growth trajectories and less numerous branches across their lifespan.The analysis of growth trajectories based on architectural analysis improved our ability to characterise the response of trees with soil types. The intraspecific variability is higher for growth trajectories than functional traits for C. obtusa, revealing the complementarity of the architectural approach with the functional approach to gain insights on the way trees manage their resources over their lifetime. Soil-related responses of Cecropia functional traits are not the same as those at the interspecific level, suggesting that the effects of the acting ecological processes are different between the two levels. Apart from soil differences, much variation was found across sites, which calls for further investigation of the factors shaping growth trajectories in tropical forests.

scholarly journals Functional traits shape ontogenetic growth trajectories of rain forest tree species

2011 ◽  
Vol 99 (6) ◽  
pp. 1431-1440 ◽  
Author(s):  
Bruno Hérault ◽  
Bénédicte Bachelot ◽  
Lourens Poorter ◽  
Vivien Rossi ◽  
Frans Bongers ◽  
...  
Keyword(s):  
Functional Traits ◽  
Tree Species ◽  
Rain Forest ◽  
Forest Tree ◽  
Growth Trajectories ◽  
Forest Tree Species

Item Bias Analysis of the Young Schema-Questionnaire for Psychopathology, Gender, and Educational Level

2011 ◽  
Vol 27 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Marleen M. Rijkeboer ◽  
Huub van den Bergh ◽  
Jan van den Bout
Keyword(s):  
Educational Level ◽  
Cross Validation ◽  
Item Bias ◽  
Response Patterns ◽  
Dutch Population ◽  
Bias Analysis ◽  
Young Schema Questionnaire ◽  
Item Functioning ◽  
Item Level ◽  
Schema Questionnaire

This study examines the construct validity of the Young Schema-Questionnaire at the item level in a Dutch population. Possible bias of items in relation to the presence or absence of psychopathology, gender, and educational level was analyzed, using a cross-validation design. None of the items of the YSQ exhibited differential item functioning (DIF) for gender, and only one item showed DIF for educational level. Furthermore, item bias analysis did not identify DIF for the presence or absence of psychopathology in as much as 195 of the 205 items comprising the YSQ. Ten items, however, spread over the questionnaire, were found to yield relatively inconsistent response patterns for patients and nonclinical participants.

CROSS-VALIDATION IS NEEDED

1972 ◽  
Vol 17 (2) ◽  
pp. 85-86
Author(s):  
RICHARD F. Q. JOHNSON
Keyword(s):  
Cross Validation
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