| Florida
Scrub - south-central Florida |
I am
particularly interested in root structure and function and
understanding root
strategies and their implications to whole plant survival. Roots are
the most understudied
and poorly understood aspect of plant ecology.
Only recently has root ecology research begun
to receive more
focus. Roots
present many unique challenges in research because they are situated in
the soil and have numerous interactions
with soil
chemical and physical processes, mycorrhizas, soil microbes and
invertebrates,
and other roots. I
am interested in the interactions
between aboveground and belowground processes.
Here are some photos of the research areas. |
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First
part of the project was to escavate roots to determine the basic root
structure of my study species. I needed to know if the taproot accessed
deep soil water or if t was relatively shallow. Understanding basic
root structure is very important to designing research
questions
that properly address the species of interest (and choosing the
apporpriate species to use in answering the research
question).
Interestingly Quercus
laevis and Carya
floridana
had rather shallow taproots. The taproot only went down for
approximately 65cm then made a 90 degree bend to grow horizontally from
the tree. Groundwater in most of the areas in Archbold Biological
Station is only 2 m down, so deep roots are not necessary for water
access.
However, it appears that groundwater at 2m is only moderately
accessible in the dry season, so that evergreen species are water
stressed when water becomes limited in the shallow soil
layers.
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The Florida
scrub left and
pine flatwood right
plant communities are pyric with fire frequencies ranging from one to
ten years
(Abrahamson and Hartnett 1990, Myers 1990). The
scrub contains mostly evergreen tree species (Quercus
myrtifolia, Q. chapmanii, Q. geminata, Lyonia fruginea, L.
fruticosa, Pinus
elliota var.
densa, and P.
clausa) with a few but very common deciduous tree species (Carya floridana and
Quercus laevis)
with a herbaceaous and shrub understory. Also both deciduous (Vitis rotundifolia)
and evergreen (Smilax
spp.) vines
occur there.
The height and density of the vegetation depend on fire frequency.
Scrub communties close to developed land is often taller and denser
because of fire suppression. Florida scrub-jays sadly cannot survive in
dense vegetation due to increased predation. They use sentinels to warn
against potential predators, but the increase density and especially
vegetation height increases cover for predators and effectiveness of
the scrub-jay sentinels
(Breininger
1999, Breininger et al. 1995, Hailman et
al. 1994, McGowan and Woolfenden 1989).
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Here
we are extracting water from lateral roots using a vacuum method. One
end of the root is placed under vacuum and 1-cm pieces are slowly cut
from the other end. As the resistance to water flow is reduced, water
leaves the root and is collected in a small vial.
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