On the scaling and standardization of charcoal data in paleofire reconstructions

Frontiers of Biogeography

article

Crystal N.H. McMichael¹  Britte M. Heijink²  Mark B. Bush³  William D. Gosling² 

[1] University of Amsterdam;Department of Ecosystem and Landscape Dynamics, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 904 Science Park;Institute for Global Ecology, Florida Institute of Technology, 150 W University Blvd

关键词: charcoal;    data standardization;    fire activity;    paleofire;    scaling;    z-score;   

DOI  :  10.21425/F5FBG49431

学科分类：社会科学、人文和艺术（综合）

来源: International Biogeography Society

【 摘 要 】

Understanding the biogeography of past and present fire events is particularly important in tropical forest ecosystems, where fire rarely occurs in the absence of human ignition. Open science databases have facilitated comprehensive and synthetic analyses of past fire activity, but charcoal datasets must be standardized (scaled) because of variations in measurement strategy, sediment type, and catchment size.  Here, we: i) assess how commonly used metrics of charcoal scaling perform on datasets from tropical forests; ii) introduce a new method called proportional relative scaling, which down-weights rare and infrequent fire; and iii) compare the approaches using charcoal data from four lakes in the Peruvian Amazon. We found that Z-score transformation and relative scaling (existing methods) distorted the structure of the charcoal peaks within the record, inflating the variation in small-scale peaks and minimizing the effect of large peaks. Proportional relative scaling maintained the structure of the original non-scaled data and contained zero values for the absence of fire. Proportional relative scaling provides an alternative scaling approach when the absence of fire is central to the aims of the research or when charcoal is infrequent and occurs in low abundances.

【 授权许可】

CC BY