Title page for ETD etd-1416152839711171


Type of Document Dissertation
Author Heckman, John Richard
Author's Email Address jheckman@vt.edu
URN etd-1416152839711171
Title Restoration of Degraded Land: A comparison of Structural and Functional Measurements of Recovery
Degree PhD
Department Biology
Advisory Committee
Advisor Name Title
Cowles, Joseph R.
Daniels, Walter Lee
Nilsen, Erik T.
Smith, Eric P.
Cairns, John Jr. Committee Chair
Keywords
  • ecological restoration
  • plant community recovery
  • soil enzymes
  • cellulos decomposition
  • soil respiration
  • atmospheric methane uptake
  • ecosystem services
Date of Defense 1997-04-08
Availability unrestricted
Abstract

The main goals of this study were to document

the structural and functional recovery of

differently restored areas, to understand better

the relationship between the two, and to

determine which types of measurements are

best for assessing restoration success. To

address these questions, an experimental

system was created through topsoil removal

and subsequent restoration in a blocked,

completely randomized design using two levels

of soil amendment (with or without 10 kg of

leaf mulch per square meter) and three levels

of seeding treatment (no seed, a standard

reclamation mix, and an alternative, wildflower

dominated reclamation mix). All measurements

were designed to document responses due to

restoration treatment in comparison to

adjacent, undisturbed, reference sites.

Vegetation structure in amended sites, as

measured by total vegetation cover and

species richness, recovered to levels similar to

references within the two years of the study.

Plant community composition did not develop

similarity to references in any experimental

treatments. Both soil amendment and seeding

type affected cellulose decomposition rates,

with amended plots showing higher

decomposition rates than unamended, and

seeded plots exhibiting higher rates than

unseeded. Enzyme activities were largely

determined by soil amendment, but the

reference plots consistently had higher

enzymatic activity. Amended sites exhibited

significant increases over time in soil

respiration, reaching or surpassing the rates

observed in reference areas. Methane

oxidation rates were generally increased in

disturbed plots compared to undisturbed

references due to increased atmospheric

diffusion into the soil. Amended areas

exhibited depressed rates relative to

unamended, and seeding level had no

significant effect on methane oxidation. Over

all measurements, restoration of ecosystem

function was most facilitated by the addition of

the soil amendment. Seeding treatment

significantly altered the resultant plant

community, which may have substantial,

long-term consequences for succession. The

inclusion of functional parameters into

restoration assessment provides for better

overall information concerning ecosystem

performance and may add to the ability to

predict long-term success of restoration

efforts.

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