Salmon carcasses alter leaf litter species diversity effects on in-stream decomposition

2011 ◽  
Vol 68 (8) ◽  
pp. 1495-1506 ◽  
Author(s):  
Welles D. Bretherton ◽  
John S. Kominoski ◽  
Dylan G. Fischer ◽  
Carri J. LeRoy
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Ecosystem Functioning ◽  
Litter Mixtures ◽  
Salmon Carcass ◽  
Stream Biodiversity ◽  
Full Factorial ◽  
Late Stages ◽  
Diversity Effects ◽  
Salmon Carcasses

Marine-derived nutrients from salmon carcasses and leaf litter inputs from riparian vegetation may interactively support stream biodiversity and ecosystem functioning through enhanced resource heterogeneity. Using a full-factorial design of single- and mixed-species litters, we tested for influences of salmon carcasses on in-stream litter decomposition. Overall, nonadditive (synergistic and antagonistic) effects on decomposition were detected for litter species mixtures, and these effects were explained by litter species composition, but not species richness. In middle to late stages of decay, mixtures of labile (high-quality) litters showed faster than expected mass loss, and recalcitrant (low-quality) litter mixtures showed slower than expected mass loss. The presence or absence of each litter species differentially affected decomposition, but these patterns were stronger when salmon carcasses were available. Across all treatments, the influence of salmon carcasses on decomposition was most pronounced in mid-stages of litter decay, where deceleration of decomposition was likely caused by macroinvertebrates feeding on salmon carcasses and less on litter. Combined, these data demonstrate that salmon carcass inputs to streams can enhance detrital heterogeneity, alter interactions among species in litter mixtures, and influence ecosystem functioning (i.e., decomposition).

scholarly journals C, N and P fertilization in an Amazonian rainforest supports stoichiometric dissimilarity as a driver of litter diversity effects on decomposition

2014 ◽  
Vol 281 (1796) ◽  
pp. 20141682 ◽  
Author(s):  
Sandra Barantal ◽  
Heidy Schimann ◽  
Nathalie Fromin ◽  
Stephan Hättenschwiler
Keyword(s):  
Leaf Litter ◽  
Soil Fauna ◽  
Individual Species ◽  
Litter Mixtures ◽  
Mixture Effects ◽  
Wide Range ◽  
Litter Mixture ◽  
Underlying Mechanisms ◽  
Strong Control ◽  
Diversity Effects

Plant leaf litter generally decomposes faster as a group of different species than when individual species decompose alone, but underlying mechanisms of these diversity effects remain poorly understood. Because resource C : N : P stoichiometry (i.e. the ratios of these key elements) exhibits strong control on consumers, we supposed that stoichiometric dissimilarity of litter mixtures (i.e. the divergence in C : N : P ratios among species) improves resource complementarity to decomposers leading to faster mixture decomposition. We tested this hypothesis with: (i) a wide range of leaf litter mixtures of neotropical tree species varying in C : N : P dissimilarity, and (ii) a nutrient addition experiment (C, N and P) to create stoichiometric similarity. Litter mixtures decomposed in the field using two different types of litterbags allowing or preventing access to soil fauna. Litter mixture mass loss was higher than expected from species decomposing singly, especially in presence of soil fauna. With fauna, synergistic litter mixture effects increased with increasing stoichiometric dissimilarity of litter mixtures and this positive relationship disappeared with fertilizer addition. Our results indicate that litter stoichiometric dissimilarity drives mixture effects via the nutritional requirements of soil fauna. Incorporating ecological stoichiometry in biodiversity research allows refinement of the underlying mechanisms of how changing biodiversity affects ecosystem functioning.

Effects of salmon carcass decomposition on biofilm growth and wood decomposition

1999 ◽  
Vol 56 (5) ◽  
pp. 767-773 ◽  
Author(s):  
Amy K. Fisher Wold ◽  
Anne E Hershey
Keyword(s):  
Mass Loss ◽  
Woody Debris ◽  
Dry Mass ◽  
Wood Decomposition ◽  
Biofilm Growth ◽  
Salmon Carcass ◽  
Stream Biota ◽  
Significant Mass Loss ◽  
Salmon Carcasses ◽  
Significant Mass

Salmon carcasses from spawning migrations can be retained in stream ecosystems behind woody debris, boulders, and other substrata where they contribute nutrients and organic matter to the stream biota. We hypothesized that carcasses would enhance algal and microbial growth and wood decomposition. To test this, we placed wood and clay pot substrata directly downstream of decomposing salmon in the Little Knife River, Minn., U.S.A., and compared total biofilm biomass on substrata in the vicinity of decomposing salmon and upstream of salmon carcasses. After 335 days in the stream, there was a significant mass loss of wood but no apparent effect of carcass decomposition on wood mass loss. Significantly, more chlorophyll a was found on both wood and pots when carcasses were present (p < 0.05) compared with controls. Stable isotope analyses suggest that the fish-derived nitrogen was taken up by the periphyton and total biofilm. Biofilm on the pots and wood near fish showed a significant increase in ash-free dry mass (p < 0.05). We conclude that fish-derived nutrients enhanced algal and total biofilm growth but did not significantly influence wood decomposition.

Ants accelerate litter decomposition in a Costa Rican lowland tropical rain forest

2012 ◽  
Vol 28 (5) ◽  
pp. 437-443 ◽  
Author(s):  
Terrence P. McGlynn ◽  
Evan K. Poirson
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Litter Decomposition ◽  
Rain Forest ◽  
Costa Rican ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Food Web Structure ◽  
Litter Bags ◽  
Lowland Rain Forest

Abstract:The decomposition of leaf litter is governed, in part, by litter invertebrates. In tropical rain forests, ants are dominant predators in the leaf litter and may alter litter decomposition through the action of a top-down control of food web structure. The role of ants in litter decomposition was investigated in a Costa Rican lowland rain forest with two experiments. In a mesocosm experiment, we manipulated ant presence in 50 ambient leaf-litter mesocosms. In a litterbag gradient experiment, Cecropia obtusifolia litter was used to measure decomposition rate constants across gradients in nutrients, ant density and richness, with 27 separate litterbag treatments for total arthropod exclusion or partial arthropod exclusion. After 2 mo, mass loss in mesocosms containing ants was 30.9%, significantly greater than the 23.5% mass loss in mesocosms without ants. In the litter bags with all arthropods excluded, decomposition was best accounted by the carbon: phosphorus content of soil (r2 = 0.41). In litter bags permitting smaller arthropods but excluding ants, decomposition was best explained by the local biomass of ants in the vicinity of the litter bags (r2 = 0.50). Once the microarthropod prey of ants are permitted to enter litterbags, the biomass of ants near the litterbags overtakes soil chemistry as the regulator of decomposition. In concert, these results support a working hypothesis that litter-dwelling ants are responsible for accelerating litter decomposition in lowland tropical rain forests.

Carbon and nitrogen transfer in leaf litter mixtures

2013 ◽  
Vol 57 ◽  
pp. 341-348 ◽  
Author(s):  
S. Linnea Berglund ◽  
Göran I. Ågren ◽  
Alf Ekblad
Keyword(s):  
Leaf Litter ◽  
Nitrogen Transfer ◽  
Carbon And Nitrogen ◽  
Litter Mixtures

scholarly journals Radio Supernovae as Direct Evidence of Stellar Evolution in Real Time

1998 ◽  
Vol 11 (1) ◽  
pp. 367-367
Author(s):  
S.D. Van Dyk ◽  
M.J. Montes ◽  
K.W. Weiler ◽  
R.A. Sramek ◽  
N. Panagia
Keyword(s):  
Mass Loss ◽  
Stellar Evolution ◽  
Loss Rate ◽  
Direct Evidence ◽  
Mass Loss Rate ◽  
X Ray ◽  
Stringent Constraint ◽  
Clear Change ◽  
Late Stages ◽  
Circumstellar Environment

The radio emission from supernovae provides a direct probe of a supernova’s circumstellar environment, which presumably was established by mass-loss episodes in the late stages of the progenitor’s presupernova evolution. The observed synchrotron emission is generated by the SN shock interacting with the relatively high-density circumstellar medium which has been fully ionized and heated by the initial UV/X-ray flash. The study of radio supernovae therefore provides many clues to and constraints on stellar evolution. We will present the recent results on several cases, including SN 1980K, whose recent abrupt decline provides us with a stringent constraint on the progenitor’s initial mass; SN 1993J, for which the profile of the wind matter supports the picture of the progenitor’s evolution in an interacting binary system; and SN 1979C, where a clear change in presupernova mass-loss rate occurred about 104 years before explosion. Other examples, such as SNe 19941 and 1996cb, will also be discussed.

Decomposition of Populustremuloides leaf litter accelerated by addition of Alnuscrispa litter

1989 ◽  
Vol 19 (5) ◽  
pp. 674-679 ◽  
Author(s):  
Barry R. Taylor ◽  
William F. J. Parsons ◽  
Dennis Parkinson
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Rocky Mountain ◽  
Litter Type ◽  
Litter Bags ◽  
Mass Losses ◽  
Mixed Litter ◽  
Aspen Forest

Decomposition of a slow-decaying litter type is expected to be faster in the presence of a nutrient-rich, fast-decaying litter type, but this effect has never been conclusively demonstrated for deciduous leaves. In a Rocky Mountain aspen forest, we followed decomposition of leaf litter of trembling aspen (Populustremuloides), a relatively slow-decomposing, nutrient-poor species, and green alder (Alnuscrispa), a nutrient-rich, faster-decomposing species, as well as a mixture of the two, for 2 years. Mass losses over the first winter were greatest for aspen alone, probably as a result of loss of solubles, but the mass loss rate overall was lowest for aspen (k = −0.191/year) and greatest for alder (k = −0.251/year). Mass loss rate for mixed litter (k = −0.245/year) was much closer to the rate for alder than for aspen, demonstrating a marked acceleration of mass loss rates in the mixed-litter bags. At these rates, 95% mass loss would be achieved by aspen, alder, and mixed litter in 14.5, 11.5, and 11.6 years, respectively.

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