VIRGINIA COAST RESERVE ANNUAL REPORT


Name: Frank P. Day

1.  Current and pending grants and contracts
  a. Current: Belowground processes and nitrogen availability across a
dynamic, nutrient poor, barrier island landscape.  NSF.  June 1, 1990
- Nov. 30, 1993.  $400,000.
   
  REU supplement to NSF grant.  NSF.  June 1, 1992 - Nov. 30, 1993.
$6,500.
  
   Root growth and development in response to CO2 enrichment. NASA,
Kennedy Space Center.  July 2, 1992 - Sept. 30, 1993. $15,652.

  b. Pending:
   Influence of nutrients and hydrology on root growth, turnover, and
phenology on barrier islands: application of minirhizotrons. NSF.
June 1, 1993 - May 31, 1996.  $322,288.  Denied

   Integrated response to gap formation in barrier island shrub
tickets (with Don Young).  NSF.  June 1, 1993 - May 31, 1996.
$338,745.

2. Proposals in development:
   Resubmission of pending proposals if not funded.

3. Publications
  Reviewed
   Published & in press:

Conn, C.E. and F.P. Day. Belowground biomass patterns on a coastal
barrier island in Virginia.  Bull.  Torrey Bot. Club: In press.
  
Abstract: Root distribution by depth, size class and community type
was evaluated along a chronosequence on Hog Island, part of the
Virginia Coast Reserve Long Term Ecological Research site.  Total
nitrogen and phosphorus concentrations in roots were also determined.
The communities included an Ammophila breviligulata dune, two Myrica
cerifera stands and two Spartina patens communities.  Most biomass was
within the top 20 cm of soil representing 75% to 93% of total biomass.
Distributions of root mass among size classes varied among sites.  On
Spartina sites, most total biomass (70 to 84%) was in the <2 mm size
class.  The 2-5 mm size class(59%) dominated the dune site and the >5
mm size class (51% to 78%) dominated the Myrica sites.  Total biomass
increased with site age ranging from 372 g/m2 in the dune site to 4228
g/m2 in the older Myrica sites.  Nitrogen and phosphorus
concentrations were low.  In a nutrient limited ecosystem,
conservative nutrient cycling may be enhanced by slow decay and high
nutrient immobilization rates associated with poor quality litter.
Additionally, structural attributes of rooting systems such as dense
fine root mats or clonal physiognomies may reduce nutrient losses
through soil leaching.

 Day, F.P. and J.P. Megonigal.  The relationship between a variable
hydroperiod, production allocation, and belowground organic turnover
in forested wetlands. Wetlands: In press.

Abstract: Belowground processes in forested wetland ecosystems are
exceptionally important, yet attention seems to focus on surface
flooding regimes and other aboveground features of these systems.
Field studies in the Dismal Swamp and several manipulative experiments
examined belowground dynamics in relation to a flooding intensity
gradient.  Generally, more extensive flooding results in less
production allocation belowground.  Erroneous conclusions regarding
wetland production are reached if aboveground parameters alone are
considered.  Root decomposition rates are slowest where the duration
of soil saturation is the longest. Organic accumulation rates in
wetlands are determined by the amount of production of particular
biomass types (eg. leaves vs roots) and the rate at which they
decompose.  Biomass allocation patterns seem to change in response to
a flooding gradient.  This represents a major implication for wetland
ecosystem functions, as carbon allocation patterns determine the array
of litter types that affect decomposition rates and thus nutrient
availability.  The hydroperiod data from the Dismal Swamp demonstrate
the highly variable nature of flooding in forested wetlands,
especially during the growing season.  The data suggest that it is
unwise to rely on hydroperiod as a direct criterion for identifying a
jurisdictional wetland.

  In preparation:

 Lakshmi, Bharatha and F.P. Day.  Nitrogen mineralization rates across
a barrier island dune chronosequence.

 Gallagher, A., S. Kohorst, and F.P. Day.  The effects of nitrogen
limitation on biomass allocation of coastal dune grasses.

 Day, F.P.  Belowground decomposition rates determined by cotton strip
assay along a barrier island dune chronosequence.

 Day, F.P.  Effects of nitrogen limitation on biomass allocation along
a barrier island dune chronosequence.

  Non-review contributions
 Day, F.P., C. Conn, B. Lakshmi, M. Stevenson, and E. Weber.  1992.
Belowground processes and nitrogen availability across a dynamic,
nutrient poor, barrier island landscape.  Progress Report to NSF.  ODU
Research Foundation, 62 pp.

4. Published Abstracts

 Conn, C.E. and F.P. Day. 1990.  Belowground biomass allocation on a
barrier island.  ASB Bull. 37: 100.
 
 Conn, C.E. and F.P. Day.  1990.  Belowground biomass allocation along
a barrier island transect.  ESA Bull. 71 (2):124.

 Day, F. P. 1992.  Decomposition patterns determined by cotton strip
assay in a barrier island dune chronosequence.  ASB Bull. 39: 76-77.

 Day, F.P. and E.P. Weber.  1992.  A minirhizotron system designed for
the Virginia Coast Reserve Long Term Ecological Research site.  ASB
Bull. 39: 73-74.

 Patwari, A., M. J. Stevenson, and F. P. Day.  1992.  Fine root
biomass distribution along a barrier island dune chronosequence.  ASB
Bull. 39: 76.

 Conn, C. E. and F. P. Day.  1992.  Root decomposition in ridge and
swale formations on a barrier island chronosequence.  ASB Bull.  39:
76.

 Day, F. P.  1992.  Belowground decomposition rates determined by
cotton strip assay in a chronosequence of barrier island communities.
ESA Bull.  73(2): 155.

 Weber, E. P. and F. P. Day.  1992.  A minirhizotron system designed
for the Virginia Coast Reserve Long Term Ecological Research site.
ESA Bull. 73(2): 382.

 Stevenson, M. J., F. P. Day, and A. Patwari.  1992.  Fine root
biomass distribution in a chronosequence of barrier island
communities.  ESA Bull. 73(2): 356.

 Conn, C. E. and F. P. Day.  1992.  Root decomposition in ridge and
swale formations on a barrier island chronosequence.  ESA Bull. 73(2):
145.

 Conn Thomas, C.E. and F.P. Day 1993.  Environmental influences on
belowground decomposition rates along a barrier island chronosequence
of ridge and swale formations.  ASB Bull.  40:142.

 Stevenson, M. and F.P. Day.  1993.  Fine root production along a
chronosequence of barrier island communities.  ASB Bull. 40: 142-143.

 Lakshmi, B. and F.P. Day.  1993.  Soil nitrogen levels and
mineralization along a community chronosequence on a coastal barrier
island.  ASB Bull. 40: 143.

 Weber, E.P. and F.P. Day.  1993.  The effect of nitrogen
fertilization on the phenology of roots in a barrier island dune
ecosystem: a minirhizotron analysis.  ASB Bull.  40: 143.


Representative abstracts from those listed above:

 Conn Thomas, Christine E. and Frank P. Day.  Environmental influences
on belowground decomposition rates along a barrier island
chronosequence of ridge and swale formations.

Abstract: The interaction between landform age, topographic position
and environmental regime was used to study environmental controls on
belowground decomposition rates.  A standard litter type was employed
as the decomposition substrate to reduce variation from litter quality
differences.  Mean water table position dropped from younger to older
sites and was higher in swales (4.8 cm aboveground to 14.7 cm
belowground) than in ridges (91.2 cm to 116.5 cm belowground).  Mean
soil redox levels decreased with depth, exhibited no differences
between ridges (423 to 573 mV) and were lower in swales (-35 to 239
mV).  Older swales had higher soil redox levels. Mean soil pH was
similar in all sites, but declined with depth.  Mean soil temperatures
were higher in ridges (16.9 to 23.7 C) than in swales (13.4 to 17.1
C).  Mean soil water salinity was negligible in ridges (<1 ppt) and
slightly higher in swales (1-6.4 ppt).  Root litter on ridges had less
percent mass remaining (40.8-57.5%) than swales (74.2-86.3%).  Losses
were greater in older sites. Decomposition increased with increased
depth in ridges and decreased in swales. Multiple regression analysis
demonstrated hydrology and soil redox were strongly intercorrelated
and explained approximately 65% of the variation in decomposition
rates.

 Stevenson, Mark and Frank P. Day.  Fine root production along a
chronosequence of barrier island communities.

Abstract: Fine root production was quantified by an ingrowth core
method along a chronosequence of dune communities on Hog Island, a
Virginia Coast Reserve LTER site.  The dune communities are dominated
by Ammophila breviligulata, Spartina patens, and Aristida tuberculosa.
Production estimates for fine roots (< 2mm) wereestimated using
biomass ingrowth into root-free soil volumes for one growing season.
Fine root production was greater in N-fertilized plots than
nonfertilized plots.  The younger dune community (R24) had higher
production rates in nonfertilized and N- fertilized plots than the
older dune communities (R36 and R120).  These biomass production
patterns may be attributed to the moisture levels in the dunes as well
as other microenvironmental factors.

 Lakshmi, Bharatha and Frank P. Day.  Soil nitrogen levels and
mineralization along a community chronosequence on a coastal barrier
island.

 Abstract: Soil nitrogen (ammonium and nitrate-N), N-mineralization
rates and the influence of urea fertilization were determined over one
year along a community chronosequence on Hog Island, part of the
Virginia Coast Reserve LTER Site. Nitrogen concentrations increased
from younger to older dunes (0.015-0.038 g/m2) and swales (0.016-0.052
g/m2) on the island.  Most nitrogen was in the form of ammonium.
Older swales had higher concentrations than the adjacent dunes.
Fertilization of the dunes resulted in a 10-13 fold increase in
nitrogen with the highest accumulation in the oldest dune (0.501
g/m2).  Net annual N-mineralization was highest (0.053 mg kg1 day1) in
the youngest dune and fertilization increased this rate to 0.356 mg
kg1 day1.  Fertilization had a marked effect in the younger dune
(16-fold increase) but a minimal effect in the oldest dune.  Swales
showed either equal or higher mineralization rates compared with the
associated dunes, except in the oldest dune-swale association.  The
low rates in the oldest fertilized dune and its associated swale was
due to lowered concentrations of ammonium-N after soil incubations in
spring and fall.  Site, age, hydrologic regime, season and vegetation
seem to determine mineralization rates on Hog Island.

 Weber, Everett P. and Frank P. Day.  The effect of nitrogen
fertilization on the phenology of roots in a barrier island dune
ecosystem: a minirhizotron analysis.

Abstract: Little work has been done on the phenology of root growth
and senescence largely due to methodological difficulties.  The
application of minirhizotron technology has enabled the tracking of
individual roots through an entire growing season.  As a result,
direct measures of turnover, root growth, and senescence are possible.
Small plots on a 36 year old dune on Hog Island, a barrier island in
the Virginia Coast Reserve Long Term Ecological Research Site, were
fertilized with nitrogen.  Minirhizotron tubes were installed in each
fertilized and control plot.  Each tube was sampled monthly for nine
months, March through November.  Preliminary results showed an
increase in root density from March to April with the fertilized plots
showing a higher root density than the unfertilized plots for both
March (256% greater) and April (140% greater).  Only 4% of the roots
sampled in April were present in the March sampling.  The
minirhizotron method allows a high resolution perspective of the
belowground environment and direct monitoring of phenomena which
previously were obtainable only through indirect measures.

  Day, Frank P. Belowground decomposition rates determined by cotton
strip assay in a chronosequence of barrier island communities.

Abstract: The dune-swale topography of an accreting coastal barrier
island provides an opportunity to quantify the influence of hydrology,
nutrient levels, and age of the landscape unit on ecosystem processes.
In the present study, decomposition rates were assayed by the cotton
strip technique in different aged dunes and swales and in N-fertilized
plots.  The strips consistently decomposed faster in the fertilized
plots. Decomposition rates were generally greater in the summer
(0.87-1.97% tensile strength loss per day) than the spring
(0.26-0.95%).  At 5 cm depth in summer, decay was progressively faster
from young to old swales but progressively slower from young to old
dunes.  The older swales were wet but not as extensively flooded as
younger swales, and the older dunes were drier than younger dunes.  In
the older landscape units, decay rates in the dunes became more
depressed at 5 cm depth in the summer compared to the spring and
increased at 15, 25, and 35 cm.  In the older swales, rates became
more depressed at 35 cm depth in the summer and they increased nearer
the surface.  Variation in moisture, temperature, and
aerobic-anaerobic interfaces explain these patterns.


5. Professional Society Presentations

 Conn, C.E. and F.P. Day.  1990.  Belowground biomass allocation on a
barrier island.  ASB Meeting.  Baltimore, Maryland.
 
 Conn, C.E. and F.P. Day.  1990.  Belowground biomass allocation along
a barrier island transect.  ESA meeting.  Snowbird, Utah.

 Day, F.P.  1992.  The linkage between a variable hydroperiod,
belowground production, and organic turnover in the Dismal Swamp,
Virginia.  Workshop on Saturated Forested Wetlands in the Mid-Atlantic
Region.  Annapolis, Maryland.  (Invited Paper)

 Day, F.P.  1992.  Decomposition patterns determined by cotton strip
assay in a barrier island dune chronosequence.  ASB Meeting.
University of Alabama. Tuscaloosa, Alabama.

 Day, F.P. and E.P. Weber.  1992.  A minirhizotron system designed for
the Virginia Coast Reserve Long Term Ecological Research site.  ASB
Meeting. University of Alabama.  Tuscaloosa, Alabama.

 Patwari, A., M.J. Stevenson, and F.P. Day.  1992.  Fine root biomass
distribution along a barrier island dune chronosequence.  ASB Meeting.
University of Alabama.  Tuscaloosa, Alabama.

 Conn, C.E. and F.P. Day.  1992.  Root decomposition in ridge and
swale formations on a barrier island chronosequence.  ASB Meeting.
University of Alabama. Tuscaloosa, Alabama.

 Day, F.P.  1992.  Belowground decomposition rates determined by
cotton strip assay in a chronosequence of barrier island communities.
ESA Meeting.  Honolulu, Hawaii.

 Weber, E.P. and F.P. Day.  1992.  A minirhizotron system designed for
the Virginia Coast Reserve Long Term Ecological Research site.  ESA
Meeting. Honolulu, Hawaii.

 Stevenson, M.J., F.P. Day, and A. Patwari.  1992.  Fine root biomass
distribution in a chronosequence of barrier island communities.  ESA
Meeting.  Honolulu, Hawaii.

 Conn, C.E. and F.P. Day.  1992.  Root decomposition in ridge and
swale formations on a barrier island chronosequence.  ESA Meeting.
Honolulu, Hawaii.

 Day, F.P.  1992.  Wetland hydrology.  National Society of American
Foresters Meeting.  Richmond, Va. (Invited presentation)

 Conn Thomas, C.E. and F.P. Day.  1993.  Environmental influences on
belowground decomposition rates along a barrier island chronosequence
of ridge and swale formations.  ASB Meeting.  Virginia Beach, VA.

 Stevenson, M. and F.P. Day.  1993.  Fine root production along a
chronosequence of barrier island communities.  ASB Meeting.  Virginia
Beach, Va.

Lakshmi, B. and F.P. Day.  1993.  Soil nitrogen levels and
mineralization along a community chronosequence on a coastal barrier
island.  ASB Meeting. Virginia Beach, Va.

 Weber, E.P. and F.P. Day.  1993.  The effect of nitrogen
fertilization on the phenology of roots in a barrier island dune
ecosystem: a minirhzotron analysis. ASB Meeting.  Virginia Beach, Va.


6. Invited Lectures:
  None LTER related yet.

7. Intersite and cross-site activities:
 Initial contacts and discussion regarding intersite comparisons and
synthesis of minirhizotron data.

8. Network activities: None 9. International activities: None

10. Human Resources
  Graduate students:*
   Christine Conn
   Mark Stevenson
   Rett Weber
   John Dilustro

  *No theses or dissertations complete yet

  Minority contributions: None Yet

  International contributions:
   Bharatha Lakshmi (India) - post-doc 11. Service (LTER related):
  NSF-LTER review panel for Konza Prairie Site (May 1993).

12. Use of VCR for academic purposes: None

13. Data Sets Collected or Developed:

  Biological Data along Hog Island Chronosequence:
   root biomass
   root production
   fine root decomposition rates
   cotton strip assay of belowground decomposition rates
   above and belowground production in response to N fertilization
   community (species) response to N fertilization above and
belowground plant nutrient concentrations

  Other Biological Data:
   root-length density and root phenology from minirhizotron
observations in control and N-fertilized plots on 36-year old dune

  Abiotic Data from Hog Island Chronosequence:
   Soil pH
   Soil Eh (4 depths)
   Ground water depth (continuous)
   Soil temperature
   Soil N and P content
   Soil water N and P content (2 depths)
   Soil N-mineralization rates

14. Contributions to the 5-Core Areas:
  Belowground primary production across Hog Island Chronosequence
  Belowground organic turnover (decomposition) rates across Hog Island
Chronosequence
  Partial N-cycle data sets across Hog Island chronosequence