Analysis of litter decomposition in an alpine tundra

1998 ◽  
Vol 76 (7) ◽  
pp. 1295-1304 ◽  
Author(s):  
David M Bryant ◽  
Elisabeth A Holland ◽  
Timothy R Seastedt ◽  
Marilyn D Walker
Keyword(s):  
Mass Loss ◽  
Litter Decomposition ◽  
Growing Season ◽  
Plant Litter ◽  
Decay Rates ◽  
Alpine Tundra ◽  
Litter Decay ◽  
Root Litter ◽  
Nitrogen Additions

Decomposition of plant litter regulates nutrient cycling and transfers of fixed carbon to soil organic matter pools in terrestrial ecosystems. Climate, as well as factors of intrinsic litter chemistry, often govern the rate of decomposition and thus the dynamics of these processes. Initial concentrations of nitrogen and recalcitrant carbon compounds in plant litter are good predictors of litter decomposition rates in many systems. The effect of exogenous nitrogen availability on decay rates, however, is not well defined. Microclimate factors vary widely within alpine tundra sites, potentially affecting litter decay rates at the local scale. A controlled factorial experiment was performed to assess the influence of landscape position and exogenous nitrogen additions on decomposition of surface foliage and buried root litter in an alpine tundra in the Front Range of the Rocky Mountains in Colorado, U.S.A. Litter bags were placed in three communities representing a gradient of soil moisture and temperature. Ammonium nitrate was applied once every 30 days at a rate of 20 g N·m-2 during the 3-month growing season. Data, as part of the Long-Term Inter-site Decomposition Experiment Team project, were analyzed to ascertain the effects of intrinsic nitrogen and carbon fraction chemistry on litter decay in alpine systems. Soil moisture was found to be the primary controlling factor in surface litter mass loss. Root litter did not show significant mass loss following first growing season. Nitrogen additions had no effect on nitrogen retention, or decomposition, of surface or buried root litter compared with controls. The acid-insoluble carbon fraction was a good predictor of mass loss in surface litters, showing a strong negative correlation. Curiously, N concentration appeared to retard root decomposition, although degrees of freedom limit the confidence of this observation. Given the slow rate of decay and N loss from root litter, root biomass appears to be a long-term reservoir for C and N in the alpine tundra.Key words: litter decomposition, alpine tundra, nitrogen deposition, LIDET, Niwot Ridge.

scholarly journals Effects of initial microbial biomass abundance on respiration during pine litter decomposition

2019 ◽  
Author(s):  
Michaeline B.N. Albright ◽  
Andreas Runde ◽  
Deanna Lopez ◽  
Jason Gans ◽  
Sanna Sevanto ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Litter Decomposition ◽  
Microbial Growth ◽  
Plant Litter ◽  
Slight Variation ◽  
Microbial Composition ◽  
C Cycling ◽  
C Cycle ◽  
Fresh Litter

AbstractMicrobial biomass is increasingly used to predict respiration in soil organic carbon (SOC) models. Its increased use combined with the difficulty of accurately measuring this variable points a need to directly assess the importance of microbial biomass abundance for carbon (C) cycling. To test the hypothesis that the initial microbial biomass abundance (i.e. biomass abundance on new plant litter) is a strong driver of plant litter C cycling, we manipulated biomass abundance by 10 and 100-fold dilution and composition using 12 source communities on sterile pine litter and measured respiration in microcosms for 30 days. In the first two days of microbial growth on fresh litter, a 100-fold difference in initial biomass abundance caused an average difference in respiration of nearly 300%, but the effect rapidly declined to less than 30% in 10 days and to 14% in 30 days. Parallel simulations with a soil carbon model, SOMIC 1.0, also predicted a 14% difference over 30 days, consistent with the experimental results. Model simulations predicted convergence of cumulative CO2 to within 10% in three months and within 4% in three years. Rapid microbial growth likely attenuates the effects of large initial differences in biomass abundance. In contrast, the persistence of source community as an explanatory factor in driving differences in respiration across microcosms supports the importance of microbial composition in C cycling. Overall, the results suggest that the initial abundance of microbial biomass on litter is a weak driver of C flux from litter decomposition over long timescales (months to years) when litter communities have equal nutrient availability. By extension, slight variation in the timing of microbial dispersal to fresh litter is likely to be a minor factor in long-term C flux.ImportanceMicrobial biomass is one of the most common microbial parameters used in land carbon (C) cycle models, however, it is notoriously difficult to measure accurately. To understand the consequences of mismeasurement, as well as the broader importance of microbial biomass abundance as a direct driver of ecological phenomena, greater quantitative understanding of the role of microbial biomass abundance in environmental processes is needed. Using microcosms, we manipulated the initial biomass of numerous microbial communities across a 100-fold range and measured effects on CO2 production during plant litter decomposition. We found that the effects of initial biomass abundance on CO2 production was largely attenuated within a week, while the effects of community type remained significant over the course of the experiment. Overall, our results suggest that initial microbial biomass abundance in litter decomposition within an ecosystem is a weak driver of long-term C cycling dynamics.

scholarly journals Fungi exposed to chronic nitrogen enrichment are less able to decay leaf litter

2016 ◽  
Author(s):  
Linda T.A. van Diepen ◽  
Serita D. Frey ◽  
Elizabeth A. Landis ◽  
Eric W. Morrison ◽  
Anne Pringle
Keyword(s):  
Growth Rates ◽  
Common Garden ◽  
N Deposition ◽  
Plant Litter ◽  
Atmospheric N Deposition ◽  
Saprotrophic Fungi ◽  
Soil C ◽  
Litter Decay ◽  
N Enrichment

AbstractSaprotrophic fungi are the primary decomposers of plant litter in temperate forests, and their activity is critical for carbon (C) and nitrogen (N) cycling. Simulated atmospheric N deposition is associated with reduced fungal biomass, shifts in fungal community structure, slowed litter decay, and soil C accumulation. Although rarely studied, N deposition may also result in novel selective pressures on fungi, affecting evolutionary trajectories. To directly test if long-term N enrichment reshapes fungal behaviors, we isolated decomposer fungi from a longterm (28 year) N addition experiment and used a common garden approach to compare growth rates and decay abilities of isolates from control and N amended plots. Both growth and decay were significantly altered by long-term exposure to N enrichment. Changes in growth rates were idiosyncratic, but litter decay by N isolates was generally lower compared to control isolates of the same species, a response not readily reversed when N isolates were grown in control (low N) environments. Changes in fungal behaviors accompany and perhaps drive previously observed N-induced shifts in fungal diversity, community composition, and litter decay dynamics.

 Implementation of mycorrhizal mechanism into a soil carbon model improves the prediction of long-term processes of plant litter decomposition

2021 ◽  
Author(s):  
Weilin Huang ◽  
Peter van Bodegom ◽  
Toni Viskari ◽  
Jari Liski ◽  
Nadejda Soudzilovskaia
Keyword(s):  
Soil Carbon ◽  
Litter Decomposition ◽  
Arbuscular Mycorrhizae ◽  
Plant Litter ◽  
Climate Impacts ◽  
Microbial Interactions ◽  
Soil C ◽  
Plant Litter Decomposition ◽  
C Dynamics

<p>Mycorrhizae, a plant-fungal symbiosis, is an important contributor to below ground-microbial interactions, and hypothesized to play a paramount role in soil carbon (C) sequestration. Ectomycorrhizae (EM) and arbuscular mycorrhizae (AM) are the two dominant forms of mycorrhizae featured by nearly all Earth plant species. However, the difference in the nature of their contributions to the processes of plant litter decomposition is still understood poorly. Current soil carbon models treat mycorrhizal impacts on the processes of soil carbon transformation as a black box. This retards scientific progress in mechanistic understanding of soil C dynamics.</p><p>We examined four alternative conceptualizations of the mycorrhizal impact on plant litter C transformations, by integrating AM and EM fungal impacts on litter C pools of different recalcitrance into the soil carbon model Yasso15. The best performing concept featured differential impacts of EM and AM on a combined pool of labile C, being quantitatively distinct from impacts of AM and EM on a pool of recalcitrant C.</p><p>Analysis of time dynamics of mycorrhizal impacts on soil C transformations demonstrated that these impacts are larger at the long-term (>2.5yrs) litter decomposition processes, compared to the short-term processes. We detected that arbuscular mycorrhizae controls shorter term decomposition of labile carbon compounds, while ectomycorrhizae dominate the long term decomposition processes of highly recalcitrant carbon elements. Overall, adding our mycorrhizal module into the Yasso model greatly improved the accuracy of the temporal dynamics of carbon sequestration.</p><p>A sensitivity analysis of litter decomposition to climate and mycorrhizal factors indicated that ignoring the mycorrhizal impact on the decomposition leads to an overestimation of climate impacts. This suggests that being co-linear with climate impacts, mycorrhizal impacts could be partly hidden within climate factors in soil carbon models, reducing the capability of such models to mechanistically predict impacts of climate vs vegetation change on soil carbon dynamics.</p><p>Our results provide a benchmark to mechanistic modelling of microbial impacts on soil C dynamics. This work opens new pathways to examining the impacts of land-use change and climate change on plant-microbial interactions and their role in soil C dynamics, allowing the integration of microbial processes into global vegetation models used for policy decisions on terrestrial carbon monitoring.</p>

scholarly journals Microsites and early litter decomposition patterns in the soil and forest canopy at regional scale

2020 ◽  
Vol 151 (1) ◽  
pp. 15-30
Author(s):  
Yonatan Aguilar-Cruz ◽  
José G. García-Franco ◽  
Gerhard Zotz
Keyword(s):  
Mass Loss ◽  
Litter Decomposition ◽  
Green Tea ◽  
Forest Canopy ◽  
Regional Scale ◽  
Elevational Gradient ◽  
Plant Litter ◽  
Dry Forest ◽  
Standard Material ◽  
Rooibos Tea

Abstract Plant litter decomposition is a key ecological process that is mostly studied at the forest floor. However, decomposition generally starts in the canopy. In this study, we evaluated the effect of litter composition and climate on the initial phase of decomposition in the soil and two contrasting types of canopy microsites along an elevational gradient (0–2200 m a.s.l.). To this end, we incubated standard material composed by green (fast decomposing) and rooibos (slow decomposing) tea bags for three months. Tea bags were placed in soil (buried at 5 cm) and in the canopy at ca. 5 m above the ground in “micro-wetlands” (tank bromeliads) and dry crown microsites (branches). Along the elevational gradient, green tea decomposed faster than rooibos tea in all microsites and forests. Mass loss for both tea types was lowest on branches at all sites, except for green tea in a wet forest where decomposition did not significantly differ among microsites. In wet forests, decomposition did not differ between bromeliads and soil, while in a dry forest, decomposition was faster in bromeliads. We found that the effects of climatic variables [monthly average temperature (TEMP) and total precipitation (PREC) for the incubation months] on decomposition differed between microsites. Along the elevational gradient, the mass loss in soil was positively correlated with TEMP but not with PREC, whereas on branches, mass loss was negatively correlated with TEMP and positively correlated with PREC. Unlike on branches, mass loss in bromeliads slightly decreased with PREC and increased with TEMP. Our study shows that microsite conditions interact with climate (TEMP and PREC) leading to differences in the general decomposition patterns in the forest canopy.

scholarly journals Decelerated carbon cycling by ectomycorrhizal fungi is controlled by substrate quality and community composition

2019 ◽  
Author(s):  
Christopher W. Fernandez ◽  
Craig R. See ◽  
Peter G. Kennedy
Keyword(s):  
Leaf Litter ◽  
Community Composition ◽  
Litter Decomposition ◽  
Fungal Community ◽  
Decay Rates ◽  
N Cycling ◽  
Substrate Quality ◽  
Litter Decay ◽  
C And N ◽  
C And N Cycling

AbstractInteractions between symbiotic ectomycorrhizal (EM) and free-living saprotrophs can result in significant deceleration of leaf litter decomposition. While this phenomenon is widely cited, its generality remains unclear, as both the direction and magnitude of EM fungal effects on leaf litter decomposition have been shown to vary among studies. Here we explicitly examine how contrasting leaf litter types and EM fungal communities may lead to differential effects on C and N cycling. Specifically, we measured the response of soil nutrient cycling, litter decay rates, litter chemistry and fungal community structure to the reduction of EM fungi (via trenching) with a reciprocal litter transplant experiment in adjacent Pinus- or Quercus-dominated sites. We found clear evidence of EM fungal suppression of C and N cycling in the Pinus-dominated site, but no suppression in the Quercus-dominated site. Additionally, in the Pinus-dominated site, only the Pinus litter decay rates were decelerated by EM fungi and were associated with decoupling of litter C and N cycling. Our results support the hypothesis that EM fungi can decelerate C cycling via N competition, but strongly suggest that the ‘Gadgil effect’ is dependent on both substrate quality and EM fungal community composition. We argue that understanding tree host traits as well as EM fungal functional diversity is critical to a more mechanistic understanding of how EM fungi mediate forest soil biogeochemical cycling.

scholarly journals Temperaturna odvisnost razgradnje opada v tleh travnikov v zaraščanju

2018 ◽  
Vol 111 (1) ◽  
pp. 189
Author(s):  
Marjetka SUHADOLC ◽  
Zalika ČREPINŠEK
Keyword(s):  
Mass Loss ◽  
Litter Decomposition ◽  
Air Temperature ◽  
Decomposition Rate ◽  
Lignin Content ◽  
Plant Litter ◽  
Litter Bags ◽  
Plant Litter Decomposition ◽  
Air Temperatures ◽  
The Difference

The aim of the study was to examine whether the effect of projected temperature rises due to the global climate change could accelerate plant litter decomposition in soils of overgrown grasslands. The experiment was carried out under natural conditions at the locations of Bohinj-Polje and Uskovnica with similar environmental conditions (precipitation, parent material and soil development, plant communities) and the difference in air temperatures. The average difference in monthly air temperatures during our study were higher in Bohinj for 4.4 °C (± 1.5 °C) than in Uskovnica. Nylon mesh bags with mixed plant litter from both locations were placed into the Of horizon of the soil profiles at both locations in autumn 2007. The litter bags were sampled successively at 4 sampling times until May 2009 in 5 replicates. The litter degradation, expressed as mass loss, was throughout our study 57.1 ± 1.2 % (0 - 526 days) in Bohinj, 57.3 ± 2.6 % (0 - 555 days) at Uskovnica. No statistically significant differences in litter decomposition rate and seasonal pattern of mass loss was found between the sites. The dynamics of the total content of cellulose and lignin, Corg and N and their soluble forms (DOC and DON) were similar between the sites as well. The lignin content in the plant material did not statistically significantly change during the experiment. The results of our experiment did not confirm the effect of the difference in average air temperature on decomposition rate decreases. The results did not confirm any effect from the difference in the average monthly air temperature between the sites on the plant litter decomposition in our study.

scholarly journals Long-term warming manipulations reveal complex decomposition responses across different tundra vegetation types

2021 ◽  
Author(s):  
Katrín Björnsdóttir ◽  
Isabel C Barrio ◽  
Ingibjörg Svala Jónsdóttir
Keyword(s):  
Mass Loss ◽  
Environmental Changes ◽  
Plant Litter ◽  
The Arctic ◽  
Vegetation Types ◽  
Positive Effects ◽  
Tundra Vegetation ◽  
Tea Bag Index ◽  
Induced Changes

In a rapidly warming tundra, ecosystems will undergo major environmental changes which are predicted to significantly alter below–ground processes, such as decomposition of plant litter. Making use of International Tundra Experiment sites (ITEX), established approximately two decades ago, we examined long–term impacts of warming on decomposition. We used the Tea Bag Index (TBI) methodology to measure the annual mass loss (%) of two tea types as a proxy for potential decomposition rates, across five tundra vegetation types. Direct effects of warming were assessed by comparing mass loss within and outside warming manipulations. Indirect effects of warming, such as those caused by warming–induced changes in plant community composition, were assessed through the relationship between mass loss of tea and biotic and abiotic local conditions. We found positive effects of warming on decomposition, although the responses varied between vegetation and tea types. Interestingly, we found support for the indirect influence of long–term warming on decomposition through warming–induced changes in the composition of plant communities. Our findings demonstrate the complexity in decomposition responses to warming across different vegetation types and highlight the importance of long–term legacies of warming in decomposition responses across the Arctic.

Analytical models of soil and litter decomposition: Solutions for mass loss and time-dependent decay rates

2012 ◽  
Vol 50 ◽  
pp. 66-76 ◽  
Author(s):  
Stefano Manzoni ◽  
Gervasio Piñeiro ◽  
Robert B. Jackson ◽  
Esteban G. Jobbágy ◽  
John H. Kim ◽  
...  
Keyword(s):  
Mass Loss ◽  
Litter Decomposition ◽  
Decay Rates ◽  
Time Dependent ◽  
Analytical Models
Sign in / Sign up

Export Citation Format

Share Document