Tail associations in ecological variables and their impact on extinction risk

Abstract

Extreme climatic events (ECEs) are becoming more frequent and more intense due to climate

A new approach to interspecific synchrony in population ecology using tail association

“…But standard methods for studying the association between two variables provide only a small slice of the information content of the association. For instance, the two pairs of variables in Figure 1a,b have identical Pearson correlation coefficients, and also have identical Spearman correlation coefficients, but nonetheless display very different patterns of association (Ghosh, Sheppard, Holder, et al, 2020; Ghosh, Sheppard, & Reuman, 2020). Correlations are not the only way to study associations, but they are very commonly used, and other standard methods in ecology provide a similarly limited amount of information that neglects patterns of association (Anderson, de Valpine, Punnett, & Miller, 2018; Genest & Favre, 2007; Joe, 2014; Mai & Scherer, 2017; Nelsen, 2006) that seem likely to be ecologically important (Ghosh, Sheppard, Holder, et al, 2020; Ghosh, Sheppard, & Reuman, 2020).…”

“…Copulas can also be used to study multivariate data. Copula approaches are applied widely and to great effect in fields such as finance and neuroscience (Emura & Chen, 2016; Goswami, Hazra, & Goyal, 2018; Kim et al., 2008; Li, 2000; Li, Xie, & Hu, 2013; Onken, Grünwälder, Munk, & Obermayer, 2009; Serinaldi, 2008; She & Xia, 2018), but only rarely, so far, in ecology (Anderson et al., 2018; Ghosh, Sheppard, Holder, et al, 2020; Ghosh, Sheppard, & Reuman, 2020; Popovic, Warton, Thomson, Hui, & Moles, 2019; Valpine, Scranton, Knape, Ram, & Mills, 2014). The potential of copulas for improving ecological understanding was argued by Ghosh, Sheppard, Holder, et al (2020), and those authors also introduced tail association as an important aspect of copula structure and elaborated the relationship between tail association and copulas.…”

Writing mathematical ecology: A guide for authors and readers

“…We suggest that the authors' role in overcoming this problem lies in emphasizing the ecological context and motivation for theoretical studies. For example, to provide motivation for their study on tail associations in distributions of ecological variables, Ghosh et al (2020) provide a graphical depiction of right and left tail associations and use a previously undescribed example of spring rainfall to depict plausible ecological scenarios that could produce different mathematical outcomes. By pairing relevant mathematical concepts with simple examples in the introduction, Ghosh et al (2020) lay the groundwork for the reader to follow the central thesis of the manuscript-why tail associations are important to consider for extinction risks of populations.…”

“…For example, to provide motivation for their study on tail associations in distributions of ecological variables, Ghosh et al. (2020) provide a graphical depiction of right and left tail associations and use a previously undescribed example of spring rainfall to depict plausible ecological scenarios that could produce different mathematical outcomes. By pairing relevant mathematical concepts with simple examples in the introduction, Ghosh et al.…”

“…By pairing relevant mathematical concepts with simple examples in the introduction, Ghosh et al. (2020) lay the groundwork for the reader to follow the central thesis of the manuscript—why tail associations are important to consider for extinction risks of populations.…”