Trophic-level dependent effects on CO2 emissions from experimental stream ecosystems

Atwood, Trisha B., Hammill, Edd and Richardson, John S. (2014) Trophic-level dependent effects on CO2 emissions from experimental stream ecosystems. Global Change Biology, 20 11: 3386-3396. doi:10.1111/gcb.12516

Author Atwood, Trisha B.
Hammill, Edd
Richardson, John S.
Title Trophic-level dependent effects on CO2 emissions from experimental stream ecosystems
Journal name Global Change Biology   Check publisher's open access policy
ISSN 1354-1013
Publication date 2014-11
Year available 2014
Sub-type Article (original research)
DOI 10.1111/gcb.12516
Open Access Status
Volume 20
Issue 11
Start page 3386
End page 3396
Total pages 11
Place of publication Chichester, West Sussex, United Kingdom
Publisher Wiley-Blackwell Publishing
Collection year 2015
Language eng
Abstract Concern over accelerating rates of species invasions and losses have initiated investigations into how local and global changes to predator abundance mediate trophic cascades that influence CO2 fluxes of aquatic ecosystems. However, to date, no studies have investigated how species additions or losses at other consumer trophic levels influence the CO2 flux of aquatic ecosystems. In this study, we added a large predatory stonefly, detritivorous stonefly, or grazer tadpole to experimental stream food webs and over a 70-day period quantified their effects on community composition, leaf litter decomposition, chlorophyll-a concentrations, and stream CO2 emissions. In general, streams where the large grazer or large detritivore were added showed no change in total invertebrate biomass, leaf litter loss, chlorophyll-a concentrations, or stream CO2 emissions compared with controls; although we did observe a spike in CO2 emissions in the large grazer treatment following a substantial reduction in chlorophyll-a concentrations on day 28. However, the large grazer and large detritivore altered the community composition of streams by reducing the densities of other grazer and detritivore taxa, respectively, compared with controls. Conversely, the addition of the large predator created trophic cascades that reduced total invertebrate biomass and increased primary producer biomass. The cascading effects of the predator additions on the food web ultimately led to decreased CO2 emissions from stream channels by up to 95%. Our results suggest that stream ecosystem processes were more influenced by changes in large predator abundance than large grazer or detritivore abundance, because of a lack of functionally similar large predators. Our study demonstrates that the presence/absence of species with unique functional roles may have consequences for the exchange of CO2 between the ecosystem and the atmosphere.
Keyword Biodiversity
Carbon efflux
Ecosystem function
Food web
Trophic cascades
Trophic level
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Global Change Institute Publications
Official 2015 Collection
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Citation counts: TR Web of Science Citation Count  Cited 3 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 3 times in Scopus Article | Citations
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