Long-term demographic balance in the Broadstone stream insect community

Douglas Speirs, William Gurney, A. Hildrew, J.H. Winterbottom

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Population models based on Lotka–Volterra-type differential equations with logistic prey were made for a simple stream community including two stonefly prey Leuctra nigra Olivier and Nemurella pictetii Klàpalek, and two predators, the caddisfly Plectrocnemia conspersa (Curtis) and the alderfly Sialis fuliginosa Pictet. In order to assess the importance of predation in this system, we constructed both an explicit four-species model and a simplified model with two functional groups which was more amenable to analytical treatment.

The models were parameterized using new data on adult emergence and recruitment combined with previously published data on larval densities and prey uptake. The models were falsified if parameterizations led either to negative prey carrying capacities or to unstable dynamics.

Both the functional group and four-species models predict asymptotically stable interactions, with feasible carrying capacities. The models are consistent in predicting that the observed prey are in excess of 70% of their carrying capacities. The four-species model indicates that predation impact is not evenly shared between the two prey, with L. nigra being depressed further from its carrying capacity than N. pictetii.

Sensitivity analysis shows that the results of the full four-species model remain very robust to realistic levels of stochastic variation in the input data.

The four-species model is used to predict the outcome of an ongoing large-scale field experiment involving the transfer of all S. fuliginosa eggs from one stretch of the stream to another. Although the equilibrial prey populations are barely affected by the manipulation, the model predicts marked transient prey-release and prey-depression of L. nigra in the predator addition and removal areas, respectively.
LanguageEnglish
Pages45-58
Number of pages24
JournalJournal of Animal Ecology
Volume69
Issue number1
DOIs
Publication statusPublished - Jan 2000

Fingerprint

insect communities
demographic statistics
insect
carrying capacity
functional group
Sialis
Sialidae
predation
Leuctra
predator
predators
stonefly
caddisfly
Plecoptera
Trichoptera
sensitivity analysis
eclosion
logistics
parameterization

Keywords

  • stream ecosystem
  • population models
  • predation impact
  • indirect interactions

Cite this

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title = "Long-term demographic balance in the Broadstone stream insect community",
abstract = "Population models based on Lotka–Volterra-type differential equations with logistic prey were made for a simple stream community including two stonefly prey Leuctra nigra Olivier and Nemurella pictetii Kl{\`a}palek, and two predators, the caddisfly Plectrocnemia conspersa (Curtis) and the alderfly Sialis fuliginosa Pictet. In order to assess the importance of predation in this system, we constructed both an explicit four-species model and a simplified model with two functional groups which was more amenable to analytical treatment. The models were parameterized using new data on adult emergence and recruitment combined with previously published data on larval densities and prey uptake. The models were falsified if parameterizations led either to negative prey carrying capacities or to unstable dynamics. Both the functional group and four-species models predict asymptotically stable interactions, with feasible carrying capacities. The models are consistent in predicting that the observed prey are in excess of 70{\%} of their carrying capacities. The four-species model indicates that predation impact is not evenly shared between the two prey, with L. nigra being depressed further from its carrying capacity than N. pictetii. Sensitivity analysis shows that the results of the full four-species model remain very robust to realistic levels of stochastic variation in the input data. The four-species model is used to predict the outcome of an ongoing large-scale field experiment involving the transfer of all S. fuliginosa eggs from one stretch of the stream to another. Although the equilibrial prey populations are barely affected by the manipulation, the model predicts marked transient prey-release and prey-depression of L. nigra in the predator addition and removal areas, respectively.",
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Long-term demographic balance in the Broadstone stream insect community. / Speirs, Douglas; Gurney, William; Hildrew, A.; Winterbottom, J.H.

In: Journal of Animal Ecology, Vol. 69, No. 1, 01.2000, p. 45-58.

Research output: Contribution to journalArticle

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AU - Winterbottom, J.H.

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AB - Population models based on Lotka–Volterra-type differential equations with logistic prey were made for a simple stream community including two stonefly prey Leuctra nigra Olivier and Nemurella pictetii Klàpalek, and two predators, the caddisfly Plectrocnemia conspersa (Curtis) and the alderfly Sialis fuliginosa Pictet. In order to assess the importance of predation in this system, we constructed both an explicit four-species model and a simplified model with two functional groups which was more amenable to analytical treatment. The models were parameterized using new data on adult emergence and recruitment combined with previously published data on larval densities and prey uptake. The models were falsified if parameterizations led either to negative prey carrying capacities or to unstable dynamics. Both the functional group and four-species models predict asymptotically stable interactions, with feasible carrying capacities. The models are consistent in predicting that the observed prey are in excess of 70% of their carrying capacities. The four-species model indicates that predation impact is not evenly shared between the two prey, with L. nigra being depressed further from its carrying capacity than N. pictetii. Sensitivity analysis shows that the results of the full four-species model remain very robust to realistic levels of stochastic variation in the input data. The four-species model is used to predict the outcome of an ongoing large-scale field experiment involving the transfer of all S. fuliginosa eggs from one stretch of the stream to another. Although the equilibrial prey populations are barely affected by the manipulation, the model predicts marked transient prey-release and prey-depression of L. nigra in the predator addition and removal areas, respectively.

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