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Archive for July, 2013

Abstract

Aim

Large trees (d.b.h. ≥ 70 cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, potentially leading to declining forest biomass storage. Here we determine the importance of large trees for tropical forest biomass storage and explore which intrinsic (species trait) and extrinsic (environment) variables are associated with the density of large trees and forest biomass at continental and pan-tropical scales.

Location

Pan-tropical.

Methods

Aboveground biomass (AGB) was calculated for 120 intact lowland moist forest locations. Linear regression was used to calculate variation in AGB explained by the density of large trees. Akaike information criterion weights (AICc-wi) were used to calculate averaged correlation coefficients for all possible multiple regression models between AGB/density of large trees and environmental and species trait variables correcting for spatial autocorrelation.

Results

Density of large trees explained c. 70% of the variation in pan-tropical AGB and was also responsible for significantly lower AGB in Neotropical [287.8 (mean) ± 105.0 (SD) Mg ha−1] versus Palaeotropical forests (Africa 418.3 ± 91.8 Mg ha−1; Asia 393.3 ± 109.3 Mg ha−1). Pan-tropical variation in density of large trees and AGB was associated with soil coarseness (negative), soil fertility (positive), community wood density (positive) and dominance of wind dispersed species (positive), temperature in the coldest month (negative), temperature in the warmest month (negative) and rainfall in the wettest month (positive), but results were not always consistent among continents.

Main conclusions

Density of large trees and AGB were significantly associated with climatic variables, indicating that climate change will affect tropical forest biomass storage. Species trait composition will interact with these future biomass changes as they are also affected by a warmer climate. Given the importance of large trees for variation in AGB across the tropics, and their sensitivity to climate change, we emphasize the need for in-depth analyses of the community dynamics of large trees.

Keywords:

Climate; ectomycorrhizal associations; large tree density; pan-tropical analysis; soils; species traits; tree size; tropical forest biomass; wood density; wind dispersal

 

Article first published online: 9 JUL 2013

DOI: 10.1111/geb.12092

Source: http://onlinelibrary.wiley.com/doi/10.1111/geb.12092/abstract

Global Ecology and Biogeography

Volume 22, Issue 12,  pages 1261–1271, December 2013

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Abstract

Human impacts have seriously damaged mangroves, and conservation of mangroves will require information on local and regional population genetic structures. Here, we report the development and polymorphism of eleven novel microsatellite markers, developed using next-generation sequencing on 56 samples of widespread mangrove species Xylocarpus granatum (Meliaceae) from nine populations across the Indo-West Pacific region. All loci were found to be polymorphic, with the number of alleles per locus ranging from four to 19. In a population from Sabah (Malaysia), the mean observed and expected heterozygosity per locus was 0.59 and 0.58, respectively. No null allele, significant linkage disequilibrium or deviation from Hardy–Weinberg equilibrium was detected among all loci. The eleven markers developed can be valuable tools to conservation genetics of this species across its distributional range.

Full paper: http://link.springer.com/article/10.1007/s12686-013-9990-9

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