Research
Undergraduate
Research
Why do research as an undergraduate? The first and foremost reason should be to enhance your skills as a biologist-developing a testable hypothesis, designing the appropriate experiment, carrying out the project, and public presentation of your results.
Interested in working in Dr. Pascarella's Plant Ecology Lab at VSU as an undergraduate? Contact me at jbpascar@valdosta.edu or at (229) 333-5766. At least a one-semester commitment is required with preference for longer time periods; You will be able to gain academic credit through directed study for your work. A strong academic record at VSU and a recommendation letter, if I have not had you in one of my classes, is requested. I encourage students of underrepresented groups to contact me regarding research opportunities.
Graduate
Research
I will accept MS students who are interested in any aspect of ecology and evolution although I prefer that students have an interest in plant demography or plant-animal interactions. I am comfortable working with students who plan on a terminal MS degree as well as those who plan to continue for a PhD. I have no preference for whether students want to focus on applied or basic research. Students should plan on applying for a teaching assistantship. If funding for a research assistantship becomes available, I will post that here.
Local Research
Projects that could involve Undergraduate or Graduate Students
1) Evolutionary ecology of reproductive isolation between two sympatric Gelsemium species (G.
rankinii and G. sempervirens) in
The following VSU undergraduate students have worked with me on various aspects of this project:
1999-Darrell Alderman, Stephanie Wright, Misty Flantroy;
2000-Dawn Down, Amie Waldron;
2002-Anna Salvador;
2007-Lovie Mansfield
Previous research found that these two species of native vines co-occur but do not hybridize. My research has revealed that the two species share the same pollinator (the blueberry bee) but flower at distinct times (Pascarella 2007). The following topics need to be addressed in order to understand this process:
A) What is the mechanism that controls flowering time for these species? Greenhouse and field studies are needed to address variation in flowering time as this variation appears critical to preventing pollen movements between the species. Greenhouse studies could use the environmental growth chambers and the greenhouses to vary environmental variables such as light, temperature, and water and their effects on flowering. In the field studies, we will plant both species along the natural gradient that defines the habitat of both species (wetland (G. rankiniii) to uplands (G. sempervirens). Ideally, genetic clones of each species would be used to minimize individual genetic variation. The first step in this process is to develop clonally propagated individuals of each species for use in greenhouse and field studies. A potential MS thesis would be to examine the flowering response and associated physiological variables (water potential, photosynthetic rate) to determine the underlying mechanisms regulating this important isolating mechanism.
B) Impact of co-flowering on individual fitness. By manipulating flowering time in the greenhouse, artificial arrays of either pure or mixed species can be developed and effects on individual fitness can be examined. A potential MS thesis here would involve looking at pollinator attraction and movement and pollen delivery and fruit set in pure vs mixed arrays. Because the two species are incompatible, the prediction is that mixed arrays of co-flowering species should show reduced fruit and/or seed set in comparison to pure arrays. However, this will depend on whether pollinators show assortative or non-random movement patterns between species and the effects of pollen clogging on stigma reception and pollen tube growth.
Foraging Behavior of Blueberry Bees (Habropoda laboriosa)
The following undergraduate students worked with me on this project.
2004-Jacob Thompson, Rachai Kanhai, Shaneika Lumpkin;
C) Does competition for pollinator service occur between Gelsemium and Blueberry? Previous research (Pascarella, in prep.) has shown that blueberry bees forage on a wide range of plants for resources. They are believed to be dependent on blueberries, though, for pollen on which they raise their young (Bees lay eggs on balls of pollen in which the young bees hatch and feed on during their development). However, female (but not male) bees have a marked preference to visit Gelsemium over Blueberry. In addition, many bees caught foraging at blueberries carry mixed pollen loads. One possible test of this is to supplement blueberry fields with Gelsemium species and compare foraging activity and fruit and seed set for both species in supplemented areas to non-supplemented areas.
2) Demography and hybridization of the federally endangered Baptisia arachnifera.
Baptisia
arachnifera is a unique Georgia endemic species
of plant found only in a 10-square mile area near Jesup,
GA. Nearly all the populations of this species are declining and found on
private timberland used for commercial production of timber and pulp. An
experimental planting of this species at the VSU Lake Louise Field Station was
started in the late 1980’s by the former VSU Biology Dept. chairman Wayne
Faircloth, a noted botanist of the
A second area of potential
research is the putative hybridization of the species with a co-occurring
native species present at
3) Biodiversity of native bees in old-growth and secondary pine forests;
Potential research projects include 1) A net, trap, and pan-trapping study
of bee biodiversity within
Research Equipment available for use in the Pascarella Lab:
Computers, software, and peripherals: several Compaq computers, from Pentium II to Pentium IV, running Microsoft 98, 2000, and XP. Printers: HP 1300 and HP5L laserjet, 1 HP 950 Inkjet. Flatbed scanner, Panasonic Digital Camera; Microsoft Office, Sigma Plot, SigmaStat, ESRI ArcView GIS, MATLAB 6.0, Adobe Acrobat, Adobe Photoshop, BIOTA, specialized ecological software (Poptools, RAMAS, Hemispherical Canopy Analysis, etc.).
Books and Journals: Science, American Scientist, Ecology, American Journal of Botany, Castanea, Georgia Journal of Science, Biotropica; specialized ecology and statistics books and reprint collection.
Lab equipment: Olympus and Leica Stereo Dissecting Scope with digital camera mount; Olympus Compound Microscope, Balances, Drying Oven, Soil sieves, Soil shaker table, Ph Meter, Freezer and Refrigerator, Sewing machine, slides, 2 insect cabinets, Gas, Vacuum, and Water lines.
Field Equipment: Lightweight Binoculars, Tripods, Monopods, Nikon FM2 Camera, Kestrel 2000 and 3000 field meterological samplers, Lux (light) meter, humidity meter, meter tapes, aluminum tags, GPS Unit, Laser Range Finder, insect nets, Refractometer, Portable field vacuum, clinometers, compass, tree dbh tapes and increment measures, soil sampling probes, tree height measurer, extendible tree trimmer.
Other equipment available for use: Greenhouses, growth chambers, warm rooms, cold rooms, animal rooms.
Greenhouse Photos. The greenhouse is now up and running (summer 2003).
Complete list of Publications
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J.B. Pascarella. 2007. Foraging patterns of the southeastern blueberry bee Habropoda laboriosa (Apidae, Hymenoptera): Implications for understanding oligolecty. Journal of Apicultural Research.46(1): 19-27.
- J. B. Pascarella, T.M. Aide, and J. K. Zimmerman. 2007. The demography of Miconia prasina (Melastomataceae) during secondary succession in Puerto Rico. Biotropica 39: 54-61.
- J.B. Pascarella. 2007. Mechanisms of prezygotic reproductive isolation between two sympatric species, Gelsemium rankinii and Gelsemium sempervirens (Gelsemiaceae), in the southeastern United States. American Journal of Botany 94(3): 468-476.
- Carol
Horvitz, Shripad Tuljapurkar, and John Pascarella. 2005. Plant-animal
interactions in random environments: habitat-stage elasticity, seed
predators and hurricanes. Ecology 86: 3312-3322.
- J.B.
Pascarella, T. M. Aide, and J. K. Zimmerman. 2004. Short-term response of
secondary forests to hurricane disturbance in Puerto Rico, USA. Forest
Ecology and Management 199: 379-393.
- S. Tuljapurkar, C.C. Horvitz,
and J.B. Pascarella. 2003. The many growth rates and elasticities of
populations in random environments. The American Naturalist 162(4):
489-503.
- John B. Pascarella, K.D.
Waddington, and P.Neal. 2001. Non-Apoid flower
visiting fauna of Everglades National Park, FL, Biodiversity and
Conservation 10: 551-566.
- John B. Pascarella, T. Mitchell
Aide, Mayra I. Serrano, and Jess K. Zimmerman. 2000. Land use history and
regeneration of tropical forests in the Cayey Mountains, Puerto Rico, Ecosystems 3(3): 217-228.
- John B. Pascarella.
2000. A new record for the rare and endangered tree Eugenia
haematocarpa Alain (Myrtaceae) in the Sierra de Cayey Mountains,
Puerto Rico. Caribbean Journal of Science 36(1-2): 146.
- Jess K. Zimmerman, John B.
Pascarella, and T. Mitchell Aide. 2000. Barriers to forest invasion in an
abandoned pasture in Puerto Rico. Restoration Ecology 8: 350-360.
- T. Mitchell Aide, Jess K.
Zimmerman, John B. Pascarella, L. Rivera, and H. Marcano. 2000. Forest
regeneration in a chronosequence of tropical abandoned pastures:
implications for restoration ecology. Restoration
Ecology 8:328-338.
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- Carol
C. Horvitz,
- John B. Pascarella. 1998.
Hurricane disturbance, plant-animal interactions, and the reproductive
success of a tropical shrub. Biotropica
30(3) 416-424.
- John B. Pascarella.
1998. Resiliency and response to hurricane disturbance in the tropical
shrub Ardisia escallonioides (Myrsinaceae). American Journal of
Botany 85:1207-1215.
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- John B. Pascarella. 1997.
Pollination ecology of Ardisia escallonioides (Myrsinaceae). Castanea 62 (1):1-7.
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- John B. Pascarella. 1994.
Additions to the flora of south Florida: Four new species of naturalized
tropical trees. Florida Scientist 57(4):173-176.
- John B. Pascarella. 1992. Notes
on flowering phenology, nectar robbing, and pollination of Symphonia globulifera
(Clusiaceae) in a lowland rain forest in Costa
Rica. Brenesia 38:83-86.
- John B. Pascarella and Michael S. Gaines.
1991. Feeding preferences of the prairie vole (Microtus
ochrogaster) for seeds and plants from an
old-field successional community. Transactions
of the Kansas Academy of Sciences
94 (1-2): 3-11.
Past Research. Click on the hyperlinks for links to papers from each topic.
1) My dissertation research integrated a field-based
empirical study of plant-animal interactions and environmental variability with
demographic modeling using matrix models. This
work focused on the response of an understory shrub, Ardisia escallonioides,
to hurricane disturbance in
For more
information, see:
Using these models, I am also analyzing data on
the population dynamics of a tropical pioneer shrub, Miconia
prasina, across a pasture to forest
chronosequence in Puerto Rico (In review) and, in collaboration with
2) In collaboration with Drs.
More recently, I studied bee biodiversity in
old-growth longleaf pine forests at the Wade Tract in
For more information on pollinators, see
3) At the community level, I am interested in
the importance of disturbance events (fire, hurricanes, and human use in
agriculture) and non-indigenous plant species invasion on plant diversity and
dynamics. Past research has focused on regeneration patterns of native and
non-indigenous subtropical trees and shrubs following hurricanes in
For more information on hurricanes and plant community ecology, see:
4) Another interest is in plant reproductive
ecology, including plant breeding and mating systems and interactions with
insect pollinators. I have studied several tropical species, including members
of the Myrsinaceae, Clusiaceae, Picramniaceae,
and Melastomataceae. This work was
funded by the
For more information on plant mating systems, see:
John B. Pascarella. 1997. Breeding systems of Ardisia Sw. (Myrsinaceae). Brittonia 49(1):45-53.
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