IntraspecificIntraspecific CompetitionCompetition inin ViolaViola tricolortricolor.B.R. Bird, Undergrad Student, B.R. Bird, Undergrad Student,

Department of BiologyDepartment of BiologyTennessee Tech UniversityTennessee Tech University

Cookeville, TN, 38505Cookeville, TN, 38505

Introduction

• Problem: stunted growth in garden plants• Objective: Find out if intraspecific competition

plays a role in growth rate.• Hypothesis: Intraspecific competition does

affect plant growth rate.• Null Hypothesis: Plants are not affected by

intraspecific competition.

Introduction cont.

Two Main Articles Used• Article: Effects of Intraspecific Competition and Nutrient

Supply on the Endangered Northeastern Bulrush, Scirpus ancistrochaetus Schuyler (Cyperaceae)

• By: Kendra A. Lentz• Foderaro, M. A. 1997. Growth and Survival of Polygonum

aviculare L. at a Brine-contaminated site in Southeastern Ohio. The American Midland Naturalist 138: 140-152.

• Other materials used in this experiment can be found here: Literature Cited

Introduction cont.

• Lentz and Fonderaro both found that intraspecific competition did affect the plants that they were studying.

• Intraspecific competition stunted growth rate after it reached

Hypothesis

• Hypothesis: Intraspecifc competition does affect plant growth rate.

• Null Hypothesis: Plants are not affected by intraspecific competition.

Methods

• Plan: grow pansies in different densities (3,6,10 and 18) and then measure height and weight of each group.

• After they measurements are taken, the measurements will be compared (mean and t-tests).

• Expected Results: There will be a significant difference (p-value less than 0.05) between the low density and the high density group.

Methods and Material

• Data will be calculated using a series of t-tests and mean values which will then be plugged into a data form.

• Methods were modeled after Lentz and Fonderaro studies.

• T-test example:• t-test example• Dataform

Results

• The p-value between the highest density is 0.049 which states that there is a significant difference between the largest density and the small density of pansies.

• The proves the null hypothesis can be rejected.

Results ContinuedA ve r ag e S te m L e n g th

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The average stem length peaked and then stabled out.

Results ContinuedA ve r ag e W e ig h t

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The average weight also peaked and then stabled out.

The average stem length and average weight table show that the plants reached a capacity cause by nutrient supply and intraspecific competition. Only so much biomass can be supported in a limited area.

Discussion and Conclusions

• My results agreed with Lentz and Fonderaro. • Intraspecific competition does affect growth

in the plants studied.• So either adding nutrients or planting pansies

farther apart would increase the size of the individual plants.

• Literature Cited

The EndThe End

• Any Questions?Any Questions?