The impact of sustainable logging practices on gene flow dynamics of Mahogany (Swietenia macrophylla) in a continuous forest.

Germain-Aubrey, Charlotte Corinna. 2004 The impact of sustainable logging practices on gene flow dynamics of Mahogany (Swietenia macrophylla) in a continuous forest. University of Edinburgh, Royal Botanic Garden Edinburgh, Masters Thesis, 76pp.

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Tropical forests are one of the most threatened ecosystems on the planet at the moment, and logging is one of the main threats. True mahogany (Swietenia macrophylla King.) has been the target of abusive exploitation for centuries and is the most commercially important tropical timber on the international market. The species is commercially extinct within most of its range and protected in some areas; such as our study area West Botes , Rio Bravo, in Belize. Sustainable logging is being tried in the hope of finding a compromise between conservation and market demand. West Botes is a plot that has been selectively logged and the genetic diversity needs to be assessed to evaluate the actual sustainability of the logging regime. The aim of this project is to use molecular markers to assess the spatial genetic structure of the population of Swietenia macrophylla, its genetic diversity, mating system and gene flow. To do so, three different microsatellites were used on both samples from the adult trees and also on the seeds in the plot. The following results were found: heterozygosity was relatively low (0.419) and inbreeding significant (0.125) compared to other similar studies, and especially compared to an unlogged plot. The spatial genetic structure of the population reveals tight clusters of closely related trees and it seems likely that this explains the significant level of biparental inbreeding. One of the conclusions that could be drawn is that the logging regime had a negative impact on the genetic diversity. However, the forest in West Botes is currently recovering from past intense logging regimes (until 1992) and one hurricane, and so it is probably too early in the succession to have a definite idea of the real pollen inflow and diversity of the population. Also, the number of loci used in this project is much lower than in other published studies, and so more loci will need to be screened in order to gain a probable estimate of the level of incoming gene flow. Overall, the trial of a sustainable logging in Hill Bank does not seem to be entirely successful and other management proposals should be looked into and considered.

Item Type: Publication - Thesis (Masters)
Programmes: CEH Programmes pre-2009 publications > Biodiversity
UKCEH and CEH Sections/Science Areas: _ Biosystems Management
NORA Subject Terms: Ecology and Environment
Date made live: 24 Apr 2012 15:08 +0 (UTC)

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