Food web complexity is believed to deteriorate the strength of terrestrial trophic cascades whereby strong natural enemy influences on herbivores cascade to indirectly impact primary production. Predator diversity may increase food web complexity by promoting the occurrence of intraguild predation, wherein predators prey on one another and on shared prey. In such instances, theory demonstrates that the effect of predation on herbivores relaxes and cascading effects on basal resources are dampened. In a terrestrial marsh community, I compared arthropod predator influences on herbivores and plant production between a simple food web with a single predator species plus a complex food web with a diverse predator assemblage. I discovered that enhancing predator diversity dampened…
Contents
CHAPTER 1: Predator diversity dampens trophic cascades
ABSTRACT
INTRODUCTION
METHODS
Study system and general methods
Greenhouse mesocosms
Field enclosures
Assessment of arthropod population density
Assessment of plant productivity
Statistical Analyses
RESULTS
DISCUSSION
REFERENCES CITED
CHAPTER 2: Predator diversity and the functioning of ecosystems: The role of intraguild predation in dampening trophic cascades
ABSTRACT
INTRODUCTION
METHODS
Study System
Verification of the trophic identity of predators: strict vs. intraguild predators
Intraguild predation and the relationship between predator diversity and the occurrence of trophic cascades
RESULTS
Verification of the trophic identity of predators: strict vs. intraguild predators
Intraguild predation and relationship between predator diversity and the occurrence of trophic cascades
DISCUSSION
REFERENCES CITED
CHAPTER 3: A refuge from intraguild predation in complex-structured habitats: Implications for prey suppression and the strength of terrestrial trophic cascades
ABSTRACT
INTRODUCTION
METHODS
Study System
Experimental Design
RESULTS
DISCUSSION
REFERENCES CITED
BIBLIOGRAPHY
Source: University of Maryland