Plant biodiversity effects on aboveground carbon storage in second-growth and old-growth tropical forests

  • Plant biodiversity effects on aboveground carbon storage in tropical forests

  • Author / Creator
    Duran, Sandra M
  • Tropical forests are experience structural changes that may reduce carbon storage potential. These changes include increases in liana density, turnover rates of species, and increments in temperature and seasonality. Much research on aboveground carbon storage (AGC), however, has focused on the role of climate, with little understanding of the role of other biotic components. I examined the effects of plant biodiversity in its broad sense (e.g, functional types, abundance, functional traits) for aboveground carbon storage (AGC) in tropical forests. At global scales, I evaluated the relative importance of lianas, stand variables (e.g., basal area, wood density, tree size) and climate on AGC in old-growth forests. I found that stand variables are stronger predictors of carbon storage across tropical forest types, and explained more variation than climate at global scales. Climate effects on AGC were mainly driven by direct effects of climate on stand variables than by direct effects of climate on AGC, which emphasizes the importance of simultaneously evaluating direct and indirect effects of abiotic variables on AGC. I also found negative effects of liana abundance on AGC in moist forests, which harbor the greatest carbon stocks in tropical regions. My research is one of the first studies showing the impacts of lianas on carbon stocks, and the differential effect of lianas on biomass carbon across tropical forests. At regional scales I evaluated how species richness and functional diversity change along succession, and how these changes influence carbon stocks in second-growth forests in dry areas. At local scales, I used temporal data (6 years) to examine the effect of climate, stand age and functional traits in tree dynamics in dry forests. Results at regional and local scales indicate that both climate and land use changes influence stored and accumulation of AGC, but stand age was one of the most important drivers determining the recovery rate of diversity and AGC in dry forests. Species richness rather than functional diversity appears to explain more variation of AGC in secondary dry forests. The increase of tree-species richness along succession, which reflects an increase in AGC, has important implications for managing secondary forests, as carbon sinks could be maximized in higher mixed-species stands. Overall, my results indicate that different components of plant biodiversity influence carbon storage, and the relative importance of each component varies across forest types. Incorporating plant biodiversity in its broad increase the amount of variance explained by models of carbon stocks in tropical forests.

  • Subjects / Keywords
  • Graduation date
    Fall 2015
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.