Home About me Past Research Naturalist Notes References Cited
Photo Lists Photologue Interesting Links Contact me Research

Current Research
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.
Escavating Carya floridana taproots
Esacavating the structure of Carya floridana at Archbold
Digging out Quercus laevis roots
Carya floridana taproot bends after only 60cm
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.  
 Florida scrub at Archbold
flatwoods at Archbold
Florida scrub-jay
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).  
extracting water from lateral roots
extracting water from a vacuum method
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.







Home About me Past Research Naturalist Notes News
Photo Lists Photologue Interesting Links Research