The ecological scale mediates whether trees experience drought legacies in radial growth

The impact of lag effects produced by disturbances on primary production has been a major concern among ecologists during the last decade.Sudden and extreme climatic events are imposing drastic reductions in radial growth of trees as evidenced in tree-rings series Dendrochronological samples are obtained at tree level but analyzed at an aggregated scale(i.e.,mean chronologies),although aggregating tree-ring chronology on a regional scale may reduce the possibility of studying the variability of individual tree response to drought,by amplifying the average population response.Here,we conducted experimental research in which 370 trees of 5 species were analyzed to assess the potential statistical and scaling issues that may occur when using regressionbased methods to analyze ecosystem responses to disturbances.Drought legacy effects were quantified using individual and aggregated scales.Then,lag effects were validated using confidence and prediction intervals to identify values falling outside the certainty of the climate-growth model Individual scale legacy effects contrasted with confidence intervals were commonly distributed across species but were scarce when compared with prediction intervals.The analysis of aggregated scale legacies detected significant growth reductions when validated using prediction intervals;however,individual scale legacy lag effects were not detected.This finding directly contrasts the results obtained when using an aggregated scale.Our results provide empirical evidence on how aggregating ecological data to infer processes that emerge from an individual scale can lead to distorted conclusions.We therefore encourage the use of individual based statistical and ecological procedures to analyze tree rings as a means of further understanding the ecosystem responses to disturbances.

A primer on multiscale modelling of infectious disease systems

The development of multiscale models of infectious disease systems is a scientific endeavour whose progress depends on advances on three main frontiers:(a)the conceptual framework frontier,(b)the mathematical technology or technical frontier,and(c)the scientific applications frontier.The objective of this primer is to introduce foundational concepts in multiscale modelling of infectious disease systems focused on these three main frontiers.On the conceptual framework frontier we propose a three-level hierarchical framework as a foundational idea which enables the discussion of the structure of multiscale models of infectious disease systems in a general way.On the scientific applications frontier we suggest ways in which the different structures of multiscale models can serve as infrastructure to provide new knowledge on the control,elimination and even eradication of infectious disease systems,while on the mathematical technology or technical frontier we present some challenges that modelers face in developing appropriate multiscale models of infectious disease systems.We anticipate that the foundational concepts presented in this primer will be central in articulating an integrated and more refined disease control theory based on multiscale modelling-the all-encompassing quantitative representation of an infectious disease system.