A conceptual framework to deal with outliers in ecology

Research on ecology commonly involves the need to face datasets that contain extreme or unusual observations. The presence of outliers during data analysis has been of concern for researchers generating a lot of discussion on different methods and strategies on how to deal with them and became a recurrent issue of interest in debate forums. Systematic elimination or data transformation could lead to ignore important ecological processes and draw wrong conclusions. The importance of coping with extreme observations during data analysis in ecology becomes clear in the context of relevant environmental aspects such as impact assessment, pest control, and biodiversity conservation. In those contexts, misinterpretation of results due to an incorrect processing of outliers may difficult decision making or even lead to failing to adopt the best management program. In this work, I summarized different approaches to deal with extreme observations such as outlier labeling, accommodation, and identification, using calculation and visualization methods, and provide a conceptual workflow as a general overview for data analysis.

[1]  Victoria J. Hodge,et al.  A Survey of Outlier Detection Methodologies , 2004, Artificial Intelligence Review.

[2]  J. Dauber,et al.  Landscape effects on recolonisation patterns of spiders in arable fields , 2008 .

[3]  Irad Ben-Gal Outlier Detection , 2005, The Data Mining and Knowledge Discovery Handbook.

[4]  R. Cook Influential Observations in Linear Regression , 1979 .

[5]  P. R. Lintott,et al.  Basic mathematical errors may make ecological assessments unreliable , 2017, Biodiversity and Conservation.

[6]  Jason W. Osborne,et al.  The power of outliers (and why researchers should ALWAYS check for them) , 2004 .

[7]  B. Tabachnick,et al.  Using Multivariate Statistics , 1983 .

[8]  Teri A. Crosby,et al.  How to Detect and Handle Outliers , 1993 .

[9]  Douglas M. Hawkins Identification of Outliers , 1980, Monographs on Applied Probability and Statistics.

[10]  W. J. Dixon,et al.  Analysis of Extreme Values , 1950 .

[11]  Alain F. Zuur,et al.  A protocol for data exploration to avoid common statistical problems , 2010 .

[12]  Denis Cousineau,et al.  Outliers detection and treatment: a review , 2010 .

[13]  John Howard Morgan,et al.  Remarks on the taking and recording of biometric measurements in bird ringing , 2004 .

[14]  V. Daniels,et al.  Algal blooms of the 18th and 19th centuries. , 2018, Toxicon : official journal of the International Society on Toxinology.

[15]  William S. Cleveland,et al.  Visualizing Data , 1993 .

[16]  Mia Hubert,et al.  Robust statistics for outlier detection , 2011, WIREs Data Mining Knowl. Discov..

[17]  K. Manoj,et al.  Comparison of methods for detecting outliers , 2013 .

[18]  A. Zuur,et al.  Mixed Effects Models and Extensions in Ecology with R , 2009 .

[19]  Bettie Caroline Wiggins,et al.  Detecting and Dealing with Outliers in Univariate and Multivariate Contexts. , 2000 .

[20]  Tobias Landmann,et al.  Advances in crop insect modelling methods—Towards a whole system approach , 2017 .