Lecture_10_wo_answers

Lecture_10_wo_answers - EEMB 120 Introduction to Ecology...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: EEMB 120 Introduction to Ecology October 28, 2010 Establish patterns of species composition, resource use or community structure that could result from actions of interspecific competition Determine existence and/or strength of competition using field experiments Study cases of competitive exclusion Establish patterns of co-evolution of competitors character displacement Approaches used in studying Interspecific Competition Competition between polychaetes and oligochaetes in a sandflat (Gallagher, Gardner, and Jumars, 1990) Competitors: Hobsonia florida (polychaete) 3 species of oligochaetes Resource: benthic diatoms Competition between polychaetes and oligochaetes in a sandflat Both sets of competitors are pioneer species in the seasonal succession in northern Puget Sound Both are abundant in the spring and summer months Both feed heavily on benthic diatoms potential for exploitative competition Competition between polychaetes and oligochaetes in a sandflat Studied abundances of the two species over time by sub-sampling small plots to obtain estimates of s and Ks Started plots at a variety of densities Used a graphical analysis of the Lotka- Volterra competition model to predict outcome of competition The Phase Plane Analysis Competition between polychaetes and oligochaetes in a sandflat Results : Hobsonia K 1 = 64.2 12 = 1.41 Oligochaetes K 2 = 50.7 21 = 0.75 N 2 N 1 64.2 67.6 50.7 45.5 Oligochaetes Hobsonia Model predicts competitive exclusion of Hobsonia !! Predicted time to exclusion is quite long ~450 days as s and Ks are very similar and isoclines are very close to one another Competition between polychaetes and oligochaetes in a sandflat N 2 N 1 Day 3 Day 55 At end of 55-day experiment, Oligochaetes had not excluded Polychaetes Conducted field experiment (55 days) to see if competitive exclusion occurred Results of Competition Experiment 55 day field experiment no competitive exclusion Time needed for exclusion is much longer than seasonal period when environment is favorable for growth Changing environment prevents exclusion of Hobsonia the competitive interaction never reaches equilibrium Competition between desert rodents (Heske, Brown, and Mistry 1994, page 300-...
View Full Document

Page1 / 25

Lecture_10_wo_answers - EEMB 120 Introduction to Ecology...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online