The influence of trees on soil biogeochemistry
Open Access
- Author:
- Mueller, Kevin E
- Graduate Program:
- Ecology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- November 30, 2010
- Committee Members:
- David Eissenstat, Dissertation Advisor/Co-Advisor
David Eissenstat, Committee Chair/Co-Chair
Katherine Haines Freeman, Committee Chair/Co-Chair
Jason Philip Kaye, Committee Member
Roger Tai Koide, Committee Member
Jon Chorover, Committee Member - Keywords:
- nitrogen
carbon
acidity
leaf
root
litter
species - Abstract:
- The state of terrestrial ecosystems depends on an array of biotic and abiotic reactions dominated by relatively few chemical elements. Many of these biogeochemical reactions occur in soils and are influenced by plants. Yet, there is considerable uncertainty regarding how plants shape soil biogeochemistry. The aim of my dissertation research was to improve knowledge of plant-soil interactions by studying the impacts of temperate tree species, and the characteristics that make them unique (i.e. plant traits), on soil biogeochemistry. My dissertation research addresses multiple aspects of soil biogeochemistry, but from a similar starting point: evaluation of leaf-centric hypotheses and conceptual models. One such hypothesis is that evergreen and deciduous species uniquely impact soil nutrient availability. I tested this hypothesis using a meta-analysis that accounted for environmental variability by comparing only co-occuring stands of each plant type (Chapter 1). The results show that evergreen and deciduous species have equivalent effects on soil nitrogen (N) mineralization rates and dissolved inorganic N abundance. Plant types and leaf traits are also expected to influence soil carbon (C) stocks and soil acidity. In Chapter 2, I evaluate the influence of tree species and plant traits on soil C, N, and acidity at a common garden experiment. There, my research shows variability in soil acidity and soil C are tightly linked and species impacts on these properties are mediated by leaf and root stoichiometry, soil N transformations, and calcium cycling. The final chapter addresses the influence of plant traits and functional types on the composition of soil lipids (at the same common garden experiment). I show that the abundance and distribution of soil lipids is strongly linked to leaf and root lipid signatures. I also highlight novel differences in the lipid signatures of leaves, roots, and soils beneath evergreen and deciduous species. In turn, these lipid signatures serve as tracers of organic matter sources and stabilization. Collectively, the results of my dissertation research suggest a wider range of plant traits (e.g. root traits) and biogeochemical processes must be incorporated into conceptual models of plant impacts on soil biogeochemistry.