Journal ArticleDOI
A gentle introduction to quantile regression for ecologists
TLDR
Quantile regression is a way to estimate the conditional quantiles of a response variable distribution in the linear model that provides a more complete view of possible causal relationships between variables in ecological processes.Abstract:
Quantile regression is a way to estimate the conditional quantiles of a response variable distribution in the linear model that provides a more complete view of possible causal relationships between variables in ecological processes. Typically, all the factors that affect ecological processes are not measured and included in the statistical models used to investigate relationships between variables associated with those processes. As a consequence, there may be a weak or no predictive relationship between the mean of the response variable (y) distribution and the measured predictive factors (X). Yet there may be stronger, useful predictive relationships with other parts of the response variable distribution. This primer relates quantile regression estimates to prediction intervals in parametric error distribution regression models (eg least squares), and discusses the ordering characteristics, interval nature, sampling variation, weighting, and interpretation of the estimates for homogeneous and heterogen...read more
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Journal ArticleDOI
Determinants of woody cover in African savannas
Mahesh Sankaran,Niall P. Hanan,Robert J. Scholes,Jayashree Ratnam,David J. Augustine,Brian S. Cade,Jacques Gignoux,Steven I. Higgins,Xavier Le Roux,Fulco Ludwig,Jonas Ardö,Feetham Banyikwa,Andries Bronn,Gabriela Bucini,Kelly K. Caylor,Michael B. Coughenour,Alioune Diouf,Wellington N. Ekaya,Christie J. Feral,Edmund C. February,Peter G. H. Frost,Pierre Hiernaux,Halszka Hrabar,Kristine L. Metzger,Herbert H. T. Prins,Susan Ringrose,William B. Sea,Jörg Tews,Jeff Worden,Nick Zambatis +29 more
TL;DR: It is shown, using data from 854 sites across Africa, that maximum woody cover in savannas receiving a mean annual precipitation (MAP) of less than ∼650 mm is constrained by, and increases linearly with, MAP.
Journal ArticleDOI
Species distribution models and ecological theory: A critical assessment and some possible new approaches
TL;DR: A review of recent papers suggests that ecological theory is rarely explicitly considered as mentioned in this paper, and that current theory and results support species responses to environmental variables to be unimodal and often skewed though process-based theory is often lacking.
Journal ArticleDOI
Tolerance to shade, drought, and waterlogging of temperate northern hemisphere trees and shrubs
TL;DR: Common scales of shade, drought, and waterlogging tolerance for 806 North American, European/West Asian, and East Asian temperate shrubs and trees were constructed to test the hypotheses that shade tolerance is negatively related to drought andWaterlogging tolerances, and that these correlations vary among continents and plant functional types.
Journal ArticleDOI
Nitrogen uptake, fixation and response to fertilizer N in soybeans: A review
Fernando Salvagiotti,Kenneth G. Cassman,James E. Specht,Daniel T. Walters,Albert Weiss,Achim Dobermann +5 more
TL;DR: In this paper, a comprehensive summary and interpretation of these interactions with specific emphasis on high yield environments is lacking. But the results from many N fertilization studies are often confounded by insufficiently optimized BNF or other management factors that may have precluded achieving BNF-mediated yields near the yield potential ceiling.
Journal ArticleDOI
Winners don’t punish
TL;DR: It is shown that the option of costly punishment increases the amount of cooperation but not the average payoff of the group, which suggests that costly punishment behaviour is maladaptive in cooperation games and might have evolved for other reasons.
References
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Book
Generalized Linear Models
Peter McCullagh,John A. Nelder +1 more
TL;DR: In this paper, a generalization of the analysis of variance is given for these models using log- likelihoods, illustrated by examples relating to four distributions; the Normal, Binomial (probit analysis, etc.), Poisson (contingency tables), and gamma (variance components).
Book
Applied Linear Statistical Models
TL;DR: Applied Linear Statistical Models 5e as discussed by the authors is the leading authoritative text and reference on statistical modeling, which includes brief introductory and review material, and then proceeds through regression and modeling for the first half, and through ANOVA and Experimental Design in the second half.
Journal ArticleDOI
Generalized Linear Models
TL;DR: This is the rst book on generalized linear models written by authors not mostly associated with the biological sciences, and it is thoroughly enjoyable to read.