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Food-web connectance and predator interference dampen the paradox of enrichment

Rall, B. C. and Guill, Christian and Brose, Ulrich (2008):
Food-web connectance and predator interference dampen the paradox of enrichment.
In: OIKOS, pp. 202-213, 117, (2), [Online-Edition: http://apps.isiknowledge.com/full_record.do?product=WOS&sear...],
[Article]

Abstract

Classic consumer-resource models with hyperbolic functional responses predict that enrichment increases the average biomasses of the species, but eventually leads to species' extinction due to accelerated oscillations ("paradox of enrichment"). However, empirical studies have stressed the complexity of natural food webs and the dominance of sigmoid or predator-interference functional responses, which may dampen population oscillations due to enrichment. Using analytical and numerical methods, we study enrichment effects on simple consumer-resource pairs and complex food webs with hyperbolic Holling type II (hereafter: type II), sigmoid Holling type III (hereafter: type III) and Beddington-De Angelis predator-interference functional responses (hereafter: BDA). Consumer-resource systems with a type III or BDA functional response are highly robust against accelerated oscillations due to enrichment, and the "paradox of enrichment" is resolved under certain parameter combinations. Subsequently, we simulated complex food webs with empirically-corroborated body-size structures of consumers that are ten times larger than their average resource. Our analyses demonstrate positive connectance-stability relationships with BDA or type III functional responses. Moreover, increasing connectance of these food webs also increases the robustness against enrichment in models with a BDA functional response. These results suggest that the well-known destabilising effects of connectance and enrichment found in classic models with type II functional responses may be inverted into stabilising effects in more realistic food-web models that are based on empirically-corroborated body-size structures and BDA or type III functional responses.

Item Type: Article
Erschienen: 2008
Creators: Rall, B. C. and Guill, Christian and Brose, Ulrich
Title: Food-web connectance and predator interference dampen the paradox of enrichment
Language: English
Abstract:

Classic consumer-resource models with hyperbolic functional responses predict that enrichment increases the average biomasses of the species, but eventually leads to species' extinction due to accelerated oscillations ("paradox of enrichment"). However, empirical studies have stressed the complexity of natural food webs and the dominance of sigmoid or predator-interference functional responses, which may dampen population oscillations due to enrichment. Using analytical and numerical methods, we study enrichment effects on simple consumer-resource pairs and complex food webs with hyperbolic Holling type II (hereafter: type II), sigmoid Holling type III (hereafter: type III) and Beddington-De Angelis predator-interference functional responses (hereafter: BDA). Consumer-resource systems with a type III or BDA functional response are highly robust against accelerated oscillations due to enrichment, and the "paradox of enrichment" is resolved under certain parameter combinations. Subsequently, we simulated complex food webs with empirically-corroborated body-size structures of consumers that are ten times larger than their average resource. Our analyses demonstrate positive connectance-stability relationships with BDA or type III functional responses. Moreover, increasing connectance of these food webs also increases the robustness against enrichment in models with a BDA functional response. These results suggest that the well-known destabilising effects of connectance and enrichment found in classic models with type II functional responses may be inverted into stabilising effects in more realistic food-web models that are based on empirically-corroborated body-size structures and BDA or type III functional responses.

Journal or Publication Title: OIKOS
Volume: 117
Number: 2
Divisions: 10 Department of Biology
10 Department of Biology > Ecoinformatics and computational ecology
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Date Deposited: 09 Oct 2009 06:21
Official URL: http://apps.isiknowledge.com/full_record.do?product=WOS&sear...
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