Developing forensic tools for an African timber: Regional origin is revealed by genetic characteristics, but not by isotopic signature

Mart Vlam*, Arjen de Groot, Arnoud Boom, Paul Copini, Ivo Laros, Katrui Veldhuijzen, David Zakamdi, Pieter A. Zuidema

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

18 Citations (Scopus)

Abstract

Combatting illegal timber trade requires forensic tools that independently verify claimed geographic origin of timber. Chemical and genetic wood characteristics are potentially suitable tools, but their performance at small spatial scales is unknown. Here we test whether stable isotopes and microsatellites can differentiate Tali timber (Erythrophleum spp.) at the level of forest concessions. We collected 394 wood samples from 134 individuals in five concessions in Cameroon and Congo Republic. The nearest neighbour concessions were 14 km apart and the furthest pair 836 km apart. We constructed genetic profiles using eight nuclear microsatellite markers and measured concentrations of δ18O, δ15N and δ13C. We differentiated provenances using PCA (microsatellites), ANOVA and kernel discriminant analysis (isotopes). Next, we performed assignment tests using blind samples (n = 12, microsatellites) and leave one out cross validation (LOOCV, isotopes). Isotopic composition varied strongly within concessions and only δ13C differed significantly between two concessions. As a result, LOOCV performed only marginally better than random. Genetic differentiation among provenances was also relatively low, but private alleles were commonly found. Bayesian clustering analysis correctly assigned 92% of the blind samples, including those of nearby concessions. Thus, Tali timber can be successfully assigned to the concession of origin using genetic markers, but not using isotopic composition. Isotopic differentiation may be possible at larger spatial scales or with stronger climatic or topographic variation. Our study shows that genetic analyses can differentiate the geographic origin of tropical timber at the scale of forest concessions, demonstrating their potential as forensic tools to enforce timber trade legislation.
Original languageEnglish
Pages (from-to)262-271
JournalBiological Conservation
Volume220
DOIs
Publication statusPublished - 1 Apr 2018

Keywords

  • DNA
  • Geographic origin
  • Microsatellites
  • Stable isotopes
  • Timber forensics
  • Tropical timber

Fingerprint Dive into the research topics of 'Developing forensic tools for an African timber: Regional origin is revealed by genetic characteristics, but not by isotopic signature'. Together they form a unique fingerprint.

Cite this