Does ambient substrate composition influence consumer diversity effects on algal removal?

Hydrobiologia ◽  
2010 ◽  
Vol 652 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Todd Wellnitz ◽  
Matt Troia ◽  
Megan Ring
ISRN Ecology ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-11
Author(s):  
Christopher F. Steiner

Experiments show that consumer diversity can have important effects on the control of prey diversity and abundance. However, theory also indicates that the strength of consumer effects on such properties will vary depending on system productivity and disturbance regime. Using a laboratory-based system composed of ciliate consumers and bacterial prey, I explored the interactive effects of productivity, disturbance, and consumer diversity on prey diversity and trophic-level abundance. Consumer diversity had productivity-dependent effects on bacterial prey that were consistent with theoretical expectations. At low productivity, increasing consumer diversity reduced prey abundance while at high productivity no effects were detected due to compensatory responses among bacteria. In contrast, consumer diversity had weak effects on prey diversity at low productivity but significantly depressed prey diversity at high productivity. Disturbance on consumers enhanced prey diversity but did not alter consumer diversity effects on prey. These results indicate that consumer diversity may play an important role in the regulation of prey communities, but the strength of this effect varies with system productivity.


2012 ◽  
Vol 66 (3) ◽  
pp. 257-269 ◽  
Author(s):  
J Filip ◽  
LL Müller ◽  
H Hillebrand ◽  
S Moorthi

2009 ◽  
Author(s):  
David J. Stanley ◽  
Natalie J. Allen ◽  
Helen M. Williams ◽  
Sarah J. Ross

1970 ◽  
Vol 48 (12) ◽  
pp. 1472-1479
Author(s):  
Harry C. Lord III

Thermal release profiles and retention coefficients of injected argon ions were investigated as functions of substrate composition and prior ion-irradiation history. Samples of forsterite, enstatite, oligoclase, obsidian, and cold-rolled steel were irradiated with various sequences of 1 keV H+, 4 keV He+, and 40 keV Ar+. The release temperature of the maximum argon concentration was found to be a function of incident Ar+ dose and pre-irradiation history but not substrate composition. The hydrogen or helium pre-irradiation converted the volume diffusion argon release to a low temperature defect diffusion release. An increase in the incident dose of Ar+ ions resulted in increasing the percentage of the argon released by defect diffusion, and also decreased the argon retention coefficient.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matthias Suter ◽  
Olivier Huguenin-Elie ◽  
Andreas Lüscher

AbstractAssessing the overall performance of ecosystems requires a quantitative evaluation of multifunctionality. We investigated plant species diversity effects on individual functions and overall multifunctionality in a grassland experiment with sown monocultures and mixtures comprising four key grass and legume species. Nitrogen fertilisation rates were 50, 150, and 450 kg N ha−1 yr−1 (N50, N150, N450). Ten functions were measured representing forage production, N cycling, and forage quality, all being related to either productivity or environmental footprint. Multifunctionality was analysed by a novel approach using the mean log response ratio across functions. Over three experimental years, mixture effects benefited all forage production and N cycling functions, while sustaining high forage quality. Thus, mixture effects did not provoke any trade-off among the analysed functions. High N fertilisation rates generally diminished mixture benefits. Multifunctionality of four-species mixtures was considerably enhanced, and mixture overall performance was up to 1.9 (N50), 1.8 (N150), and 1.6 times (N450) higher than in averaged monocultures. Multifunctionality of four-species mixtures at N50 was at least as high as in grass monocultures at N450. Sown grass–legume mixtures combining few complementary species at low to moderate N fertilisation sustain high multifunctionality and are a ‘ready-to-use’ option for the sustainable intensification of agriculture.


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