Abstract
Background: The impact of logging and restoration on species diversity has been well studied in tropical forests. However, little is known about their effects on genetic diversity within species.
Aims: We assess the degree of genetic diversity among dipterocarp seedlings used for enrichment planting of selectively logged forests in Sabah, Malaysia, and compare it with diversity in naturally regenerating seedlings.
Methods: We sampled young leaf tissues from seedlings of Shorea leprosula and Parashorea malaanonan for DNA genotyping, using microsatellite markers.
Results: The levels of genetic diversity (expected heterozygosity and rarefied allelic richness) of naturally regenerating seedlings were statistically indistinguishable among unlogged, once logged and repeatedly logged forest areas. Enrichment-planted seedlings of P. malaanonan exhibited similar levels of genetic diversity to naturally regenerating seedlings whereas those of S. leprosula had significantly lower genetic diversity than natural seedlings. Interestingly, reduction of genetic variation was consistently observed in single-species plots relative to mixed-species plots among enrichment-planted seedlings.
Conclusions: There was no reduction of genetic variation in naturally regenerating dipterocarp seedlings in areas of selective logging. However, genetic variation of enrichment-planted seedlings was lower in single-species plots relative to mixed-species plots. This suggests that enrichment-planting strategies should adopt diverse mixtures that should promote levels of both species richness and genetic diversity within species.
Acknowledgements
We would like to thank the staff of the Sabah Biodiversity Experiment for their assistance with the field and shade-house experiments. We appreciate the help from Alexander Karolus for providing the coordinates of dipterocarp species in the 50-ha plot, DVCA. We acknowledge the Sabah Biodiversity Centre and Danum Valley Management Committee for granting us the permission to conduct our research in the areas. This research is manuscript number 14 of the Sabah Biodiversity Experiment and supported by the University Research Priority Program on Global Change and Biodiversity of the University of Zurich, Swiss National Science Foundation, MEXT KAKENHI Grant Number 16H06469. AH is supported by the NERC Human-modified Tropical Forests programme, and CCA by Georges and Antoine Claraz-Donation.
Disclosure statement
No potential conflict of interest was reported by the authors.
Supplemental data
Supplemental data for this article can be accessed here.
Additional information
Funding
Notes on contributors
Cheng Choon Ang
The project was conceived by AH and KKS with input from MOB and BS. CCA and MOB designed the field sampling strategy and wrote the initial draft of the manuscript. CCA performed the field sampling and analysed the genetic data. KKSN and KKS provided technical and analytical advice on the genetic analysis. MOB and BS contributed in the ANOVA analysis. PCL contributed logistical and strategic help to facilitate sampling and laboratory assistance in Sabah. AH setup the SBE experiment, which was the basis for sampling the enrichment-planted seedlings. AH and BS provided sampling and statistical advice. BS and KKS are the PIs on the project that funded this research. KKSN helped with genetic analysis. All authors contributed to manuscript revisions.
Cheng Choon Ang is interested in the underlying genetic architecture and diversity of adaptive traits observed in dipterocarps.
Michael J. O’Brien
Michael J. O’Brien is interested in the effect of climate change on community composition and intra- vs. inter-specific competition of seedlings in Malaysian, Borneo.
Kevin Kit Siong Ng
Kevin Kit Siong Ng is interested in the population genetics and genomics of tropical tree species.
Ping Chin Lee
Ping Chin Lee specialises in the field of microbiology, molecular biology and cellular biology.
Andy Hector
Andy Hector is interested in biodiversity loss and its consequences for the stability and functioning of ecosystems and the provision of ecological services.
Bernhard Schmid
Bernhard Schmid is an expert in the biology of species interactions, focusing on variation among individuals, populations and species of plants and animals, and how they interact in nature and under controlled experimental conditions.
Kentaro K. Shimizu
Bernhard Schmid is an expert in the biology of species interactions, focusing on variation among individuals, populations and species of plants and animals, and how they interact in nature and under controlled experimental conditions.
Kentaro K. Shimizu is interested in evolutionary and ecological genomic studies by integrating novel genomics tools and systems biology to predict evolutionary and plastic responses in changing environments.