Colonization history determines alternate community states in a food web of intraguild predators

TY - JOUR

T1 - Colonization history determines alternate community states in a food web of intraguild predators

AU - Price, Jennifer E.

AU - Morin, Peter J.

PY - 2004/4

Y1 - 2004/4

N2 - Several recent studies suggest that community composition can take on alternate, apparently stable, states. For the most part, these studies are observational in nature and have not shown that alternate states arise from the order of species arrival during community assembly. Previous studies also provide little insight into the mechanisms that create alternate states, especially when direct species interactions, rather than environmental feedback, control their formation. We conducted experiments in identical physical environments to show that differences in the sequence of community assembly can create alternate species compositions that persist for many generations. Assembly sequence determined whether experimental food webs contained a single intraguild predator, or two intraguild predators. When the intraguild predator, Blepharisma americanum, became established in communities before the introduction of Tetrahymena vorax, combined effects of resource depletion and intraguild predation prevented the establishment of Tetrahymena. In contrast, when Tetrahymena preceded Blepharisma, both species frequently coexisted. Supporting experiments describe the exploitative competitive abilities of both intraguild predators, document the population dynamics of each species in less complex community modules, and determine the ability of Tetrahymena to invade Blepharisma cultures in the absence of competing prey. These results show that both competition and predation contribute to the formation of two alternate community states and confirm that one stable state resists transformation to the other.

AB - Several recent studies suggest that community composition can take on alternate, apparently stable, states. For the most part, these studies are observational in nature and have not shown that alternate states arise from the order of species arrival during community assembly. Previous studies also provide little insight into the mechanisms that create alternate states, especially when direct species interactions, rather than environmental feedback, control their formation. We conducted experiments in identical physical environments to show that differences in the sequence of community assembly can create alternate species compositions that persist for many generations. Assembly sequence determined whether experimental food webs contained a single intraguild predator, or two intraguild predators. When the intraguild predator, Blepharisma americanum, became established in communities before the introduction of Tetrahymena vorax, combined effects of resource depletion and intraguild predation prevented the establishment of Tetrahymena. In contrast, when Tetrahymena preceded Blepharisma, both species frequently coexisted. Supporting experiments describe the exploitative competitive abilities of both intraguild predators, document the population dynamics of each species in less complex community modules, and determine the ability of Tetrahymena to invade Blepharisma cultures in the absence of competing prey. These results show that both competition and predation contribute to the formation of two alternate community states and confirm that one stable state resists transformation to the other.

KW - Alternate stable states

KW - Blepharisma americanum

KW - Colpidium striatum

KW - Community module

KW - Food webs

KW - Intraguild predation

KW - Protists

KW - Tetrahymena vorax

UR - http://www.scopus.com/inward/record.url?scp=8144227562&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=8144227562&partnerID=8YFLogxK

U2 - https://doi.org/10.1890/03-0157

DO - https://doi.org/10.1890/03-0157

M3 - Article

SN - 0012-9658

VL - 85

SP - 1017

EP - 1028

JO - Ecology

JF - Ecology

IS - 4

ER -