umu.sePublikationer
Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
When is a type III functional response stabilizing?: theory and practice of predicting plankton dynamics under enrichment
Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Department Biologie II, Ludwig-Maximilians-Universität, München.
Department Biologie II, Ludwig-Maximilians-Universita¨t Mu¨nchen, Grosshaderner Str. 2, D-82152 Planegg-Martinsried, Germany.
Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
Visa övriga samt affilieringar
2015 (Engelska)Ingår i: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 96, nr 12, s. 3243-3256Artikel i tidskrift (Refereegranskat) Published
Resurstyp
Text
Abstract [en]

The curvature of generalized Holling type functional response curves is controlled by a shape parameter b yielding hyperbolic type II (b = 1) to increasingly sigmoid type III (b > 1) responses. Empirical estimates of b vary considerably across taxa. Larger consumer-resource body mass ratios have been suggested to generate more pronounced type III responses and therefore to promote dynamic stability. The dependence of consumer-resource stability on b has, however, not been systematically explored, and the accurate empirical determination of b is challenging. Specifically, the shape of the functional response of the pelagic grazer Daphnia feeding on phytoplankton, and its consequences for stability, remain controversial. We derive a novel analytical condition relating b to local stability of consumer-resource interactions and use it to predict stability of empirically parameterized models of Daphnia and phytoplankton under enrichment. Functional response parameters were experimentally derived for two species of Daphnia feeding separately on single cultures of two different phytoplankton species. All experimentally studied Daphnia-algae systems exhibited type III responses. Parameterized type III responses are predicted to stabilize the modeled Daphnia-phytoplankton dynamics in some species pairs but not in others. Remarkably, stability predictions differ depending on whether functional response parameters are derived from clearance vs. ingestion rates. Accurate parameter estimation may therefore require fitting to both rates. In addition, our estimates of b for filter-feeding Daphnia are much smaller than predicted for actively hunting predators at similar consumer-resource body mass ratios. This suggests that the relationship between functional response shape and body mass ratios may vary with predation mode.

Ort, förlag, år, upplaga, sidor
John Wiley & Sons, 2015. Vol. 96, nr 12, s. 3243-3256
Nyckelord [en]
body size, clearance rate, consumer-resource dynamics, Daphnia, filter feeder, functional response, gestion rate, parameter estimation, phytoplankton-zooplankton dynamics, stability
Nationell ämneskategori
Ekologi
Identifikatorer
URN: urn:nbn:se:umu:diva-114583DOI: 10.1890/15-0055.1ISI: 000367287900012OAI: oai:DiVA.org:umu-114583DiVA, id: diva2:903643
Tillgänglig från: 2016-02-16 Skapad: 2016-01-25 Senast uppdaterad: 2018-06-07Bibliografiskt granskad
Ingår i avhandling
1. Effects of warming and nutrient enrichment on feeding behavior, population stability and persistence of consumers and their resources
Öppna denna publikation i ny flik eller fönster >>Effects of warming and nutrient enrichment on feeding behavior, population stability and persistence of consumers and their resources
2016 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Consumer-resource interactions are the basic building blocks of every food web. In spite of being a central research theme of longstanding interest in ecology, the mechanisms governing the stability and persistence of consumer-resource interactions are still not entirely understood. In particular, theoretical predictions on consumer-resource stability along gradients of temperature and nutrient enrichment diverge widely and are sometimes in conflict with empirical results. In this thesis I address these issues from the angle of the functional response, which describes a consumer’s feeding rate as a function of resource density. Specifically, I explore mechanistic, nutrient-based consumer-resource interaction models with respect to the influence of feeding behavior (the shape of the functional response), environmental temperature, nutrient enrichment, and resource quality on consumer-resource stability and persistence. In order to parameterize these models I performed extensive laboratory experiments with pairs of freshwater pelagic algae and grazers of the genus Daphnia, which are widespread, ecologically important model organisms.

I found a sigmoidal type III functional response in every studied Daphnia-algae species pair. The exact form of its shape is described by an exponent b which is determined by fitting functional response models to the experimental data. A high value of b can stabilize consumer-resource systems under the otherwise destabilizing influence of nutrient enrichment, as predicted by a novel stability criterion relating b to the consumer’s prey handling time, food conversion efficiency and mortality. Estimated parameter values and, consequently, stability predictions are sensitive to the method of parameter estimation, and I propose a new estimation procedure that minimizes parameter uncertainty. Because many consumers’ feeding rates depend on temperature, warming is expected to strongly affect food web stability. In functional response experiments over a broad temperature gradient, I found that the attack rate coefficient and the maximum ingestion rate of Daphnia are hump-shaped functions of temperature. Moreover, the functional response exponent increases with warming towards stronger type III responses. Plugging these findings into a nutrient-based consumer-resource model, I found that predator persistence is a U-shaped function of temperature in nutrient enrichment-temperature space. Enrichment easily turns the system unstable when the consumer has a type II response, whereas a type III response opens up a large region of stability at intermediate, for the consumer optimal, temperatures. These findings reconcile seemingly conflicting results of earlier studies of temperature effects on consumer-resource dynamics, which can be mapped as special cases onto the enrichment-temperature space. I finally demonstrate the utility of three key model ingredients - temperature dependence of rate parameters, a mechanistic description of the dynamics of algal resources, and a type III functional response in Daphnia - by successfully implementing them in the description and explanation of phytoplankton-Daphnia dynamics in a mesocosm experiment exploring effects of warming on the spring succession of the plankton.

Ort, förlag, år, upplaga, sidor
Umeå: Umeå University, 2016. s. 27
Nyckelord
consumer-resource, Daphnia, functional response, nutrient enrichment, parameter estimation, persistence, plankton, predator-prey, stability, temperature, type II, type III, warming
Nationell ämneskategori
Ekologi
Identifikatorer
urn:nbn:se:umu:diva-124876 (URN)978-91-7601-544-5 (ISBN)
Externt samarbete:
Disputation
2016-09-20, Lilla Hörsalen (KB3A9), KBC, Umeå University, Umeå, 09:30 (Engelska)
Opponent
Handledare
Tillgänglig från: 2016-08-30 Skapad: 2016-08-29 Senast uppdaterad: 2018-06-07Bibliografiskt granskad

Open Access i DiVA

Fulltext saknas i DiVA

Övriga länkar

Förlagets fulltext

Personposter BETA

Uszko, WojciechDiehl, SebastianLengfellner, KathrinMüller, Thomas

Sök vidare i DiVA

Av författaren/redaktören
Uszko, WojciechDiehl, SebastianLengfellner, KathrinMüller, Thomas
Av organisationen
Institutionen för ekologi, miljö och geovetenskap
I samma tidskrift
Ecology
Ekologi

Sök vidare utanför DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetricpoäng

doi
urn-nbn
Totalt: 368 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf