A Poster Presentation delivered by Justin Tirrell at the Spring 2019 Student Research Symposium at Utah State University

1. Non-Cognitive Predictors of Student Success:
A Predictive Validity Comparison Between Domestic and International Students
The diet preferences of Agouties
are showing us how Tropical
Forests maintain high plant
species diversity.
Non-Cognitive Predictors of Student Success:
A Predictive Validity Comparison Between Domestic and International Students
INTRO
• When tropical rodents forget about seeds they have
buried, the buried seeds are more likely to grow into
trees7.
• Understanding the traits of seeds that predict whether
they will be buried and the pattern in which rodents
will bury seeds will help us understand how tropical
forests grow.
• Important predictors of a seed being buried are local
density (Figure 1), identities of neighboring species
(Figure 2), and the relative size of the seed (Figure 3).
• The trees being considered are Astrocaryum
standleyanum, Dipteryx oleifera, and Attalea butyracea.
These trees can be effectively used to model how
predators effect the spatial distribution of plant
populations because they have relatively few predators
that have the ability to break through the stony
endocarps that protect the seeds1.
METHODS (proposed)
1. Plots for 6 variations of high and low adult density of 3
focal tree species have been selected on Barro Colorado
Island in Panama2.
2. Random points are generated within each plot using
arcGIS. 1m2 are to be set up at each point. Seeds buried
up to 5 cm in the coil will be collected and the seed status
will be recorded3.
3. Data will be analyzed using linear regression and model
averaging techniques2. (AIC values)
RESULTS
• Increased experience writing grant proposals
• Increased familiarity with Tropical Ecology Literature
DISCUSSION
The data collected from this project will be readily available to
individuals in the scientific community who can use it to
advance programmatic and analytic models.
Title: Investigating seed size as
a driver for rodent caused
mortality on Barro Colorado
Island
Justin Tirrell, Dr. Carol
Garzon-Lopez, Dr. Noelle
Beckman
Take a picture to
read a proposal
Figure 1: Janzen-Connel Hypothesis
Seed predators regulate seed
mortality based on seed density.
Figure 2: Heterospecific Model
Seed predators cache some species
of seed preferentially.
Figure 3: Size –based Model
Seed predators s cache larger seeds
preferentially .
Figure 4: American Spiny Rat
(Proechimys semispinosus)
Figure 5: Central American Agouti
(Dosyprocta puntata)
Figure 6: Red-tailed Squirrel
(Sciurus granatensis)
1. Bradford, D. F. & Smith, C. C. 1977. Seed predation and seed number in Scheelea palm fruits. Ecology 58:667–673
2. Connell JH (1971) On the role of natural enemies in preventing competitive exclusion in some marine animals and in rain forest trees, in Boer PJD, Gradwell GR,
Editors. Dynamics of populations. Wageningen, Netherlands: Centre for Agricultural Publication and Documentation. pp. 298312
3. Gálvez, D., & Jansen, P. (2007). Bruchid beetle infestation and the value of Attalea butyracea endocarpsfor Neotropical rodents (Vol. 23).
4. Garzon-Lopez, C. X., Ballesteros-Mejia, L., Ordoñez, A., Bohlman, S. A., Olff, H., & Jansen, P. A. (2015).
5. Indirect interactions among tropical tree species through shared rodent seed predators: a novel mechanism of tree species coexistence. Ecology Letters, 18(8),
752760.
6. Janzen, D. H. 1970. Herbivores and number of tree species in tropical forests. American Naturalist (Vol. 104).
7. Kuprewicz, E. K., & García-Robledo, C. (2019). Deciphering seed dispersal decisions: Size, not tannin content, drives seed fate and survival in a tropical forest.
Ecosphere, 10(1), e02551.cvc
References
Figure 1,2,3: Free Vector Design by: <a href="https://www.vecteezy.com/">Vecteezy</a>
Figure 4: https://en.wikipedia.org/wiki/Red-tailed_squirrel#/media/File:Red-
Figure 5: https://www.britannica.com/animal/American-spiny-rat/media/560266/7509
Figure 6: https://pixabay.com/photos/agouti-rodent-animal-creature-2299623/