scholarly journals Combined effects of water temperature, grazing snails and terrestrial herbivores on leaf decomposition in urban streams

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7580 ◽  
Author(s):  
Hongyong Xiang ◽  
Yixin Zhang ◽  
David Atkinson ◽  
Raju Sekar

The decomposition of organic matter in freshwaters, such as leaf litter, can affect global nutrient (e.g., carbon) cycling. This process can be influenced by fast urbanization through increased water temperature, reduced aquatic diversity and changed leaf litter quality traits. In this study, we performed a mesocosm experiment to explore the individual and combined effects of warming (8°C higher and ambient), the presence versus absence of grazing snails (Parafossarulus striatulus), and intraspecific difference of leaf litter quality (intact versus > 40% area of Liriodendron chinense leaves grazed by terrestrial insects) on litter decomposition in urban streams. Litter decomposition rates ranged from 0.019 d−1 to 0.058 d−1 with an average decomposition rate of 0.032 ± 0.002 d−1. All the three factors had significant effects on litter decomposition rate. Warming and the presence of snails accelerated litter decomposition rates by 60% and 35% respectively. Litter decomposition rates of leaves damaged by terrestrial insects were 5% slower than that of intact leaves, because litter quality of terrestrial insect-damaged leaves was lower (i.e., higher specific leaf weight) than intact leaves. For treatments with snails, warming stimulated microbial and snail mediated litter decomposition rates by 35% and 167%, respectively. All combinations of treatments showed additive effects on litter decomposition except for the interaction between warming and snails which showed positive synergistic effects. In addition, neither temperature nor litter quality affected snail growth rate. These results imply that higher water temperature and the presence of abundant snails in urban streams greatly enhanced litter decomposition. Moreover, the effect of pest outbreaks, which resulted in lower litter quality, can cascade to aquatic ecosystems by retarding microbe-mediated litter decomposition. When these factors co-occurred, warming could synergistically interact with snails to speed up the depletion of organic matter, while the effect of leaf quality on litter decomposition may be diminished at high water temperature. These effects could further influence stream food webs and nutrient cycling.

1998 ◽  
Vol 6 (1) ◽  
pp. 1-12 ◽  
Author(s):  
M Francesca Cotrufo ◽  
Björn Berg ◽  
Werner Kratz

There is evidence that N concentration in hardwood leaf litter is reduced when plants are raised in an elevated CO2 atmosphere. Reductions in the N concentration of leaf litter have been found for tree species raised under elevated CO2, with reduction in N concentration ranging from ca. 50% for sweet chestnut (Castanea sativa) to 19% for sycamore (Acer platanoides). However, the effects of elevated CO2 on the chemical composition of litter has been investigated only for a limited number of species. There is also little information on the effects of increased CO2 on the quality of root tissues. If we consider, for example, two important European forest ecosystem types, the dominant species investigated for chemical changes are just a few. Thus, there are whole terrestrial ecosystems in which not a single species has been investigated, meaning that the observed effects of a raised CO2 level on plant litter actually has a large error source. Few reports present data on the effects of elevated CO2 on litter nutrients other than N, which limits our ability to predict the effects of elevated CO2 on litter quality and thus on its decomposability. In litter decomposition three separate steps are seen: (i) the initial stages, (ii) the later stages, and (iii) the final stages. The concept of "substrate quality," translated into chemical composition, will thus change between early stages of decomposition and later ones, with a balanced proportion of nutrients (e.g., N, P, S) being required in the early decomposition phase. In the later stages decomposition rates are ruled by lignin degradation and that process is regulated by the availability of certain nutrients (e.g., N, Mn), which act as signals to the lignin-degrading soil microflora. In the final stages the decomposition comes to a stop or may reach an extremely low decomposition rate, so low that asymptotic decomposition values may be estimated and negatively related to N concentrations. Studies on the effects of changes in chemical composition on the decomposability of litter have mainly been made during the early decomposition stages and they generally report decreased litter quality (e.g., increased C/N ratio), resulting in lower decomposition rates for litter raised under elevated CO2 as compared with control litter. No reports are found relating chemical changes induced by elevated CO2 to litter mass-loss rates in late stages. By most definitions, at these stages litter has turned into humus, and many studies demonstrated that a raising of the N level may suppress humus decomposition rate. It is thus reasonable to speculate that a decrease in N levels in humus would accelerate decomposition and allow it to proceed further. There are no experimental data on the long-term effect of elevated CO2 levels, and a decrease in the storage of humus and nutrients could be predicted, at least in temperate and boreal forest systems. Future works on the effects of elevated CO2 on litter quality need to include studies of a larger number of nutrients and chemical components, and to cover different stages of decomposition. Additionally, the response of plant litter quality to elevated CO2 needs to be investigated under field conditions and at the community level, where possible shifts in community composition (i.e., C3 versus C4 ; N2 fixers versus nonfixers) predicted under elevated CO2 are taken into account.Key words: climate change, substrate quality, carbon dioxide, plant litter, chemical composition, decomposition.


Hydrobiologia ◽  
2021 ◽  
Author(s):  
Luz Boyero ◽  
Naiara López-Rojo ◽  
Javier Pérez ◽  
Alan M. Tonin ◽  
Francisco Correa-Araneda ◽  
...  

AbstractLeaf litter decomposition is a key process in stream ecosystems, the rates of which can vary with changes in litter quality or its colonization by microorganisms. Decomposition in streams is increasingly used to compare ecosystem functioning globally, often requiring the distribution of litter across countries. It is important to understand whether litter sterilization, which is required by some countries, can alter the rates of decomposition and associated processes. We examined whether litter sterilization with gamma irradiation (25 kGy) influenced decomposition rates, litter stoichiometry, and colonization by invertebrates after weeks of instream incubation within coarse-mesh and fine-mesh litterbags. We used nine plant species from three families that varied widely in litter chemistry but found mostly consistent responses, with no differences in decomposition rates or numbers of invertebrates found at the end of the incubation period. However, litter stoichiometry differed between irradiated and control litter, with greater nutrient losses (mostly phosphorus) in the former. Therefore, the effects of irradiation on litter chemistry should be taken into account in studies focused on stoichiometry but not necessarily in those focused on decomposition rates, at least within the experimental timescale considered here.


Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1394
Author(s):  
Szabina Simon ◽  
Brigitta Simon-Gáspár ◽  
Gábor Soós ◽  
Angéla Anda

Leaf-litter input constitutes a major load in natural waters; therefore, to achieve and maintain high water quality, it is important to thoroughly examine and understand the litter decomposition process. The widespread Solidago canadensis exerts a negative effect on the composition of the ecosystem, causes extinction of species, and modifies the function of the system. In Hungary, goldenrod constantly spreads to newer areas, which can also be observed around Lake Balaton and at the bank of the Hévíz canal. In our investigation, we examined the decomposition rate of the leaves and stems of the goldenrod with the commonly applied method of leaf litter bags. As water temperature, ranging from 24.0 °C to 13.7 °C, decreases in Hévíz canal away from Lake Hévíz (−0.32 °C/100 m), we chose three different sampling sites with different water temperatures along the canal to determine how water temperature influences the rate of decomposition. For both leaves and stems, the fastest decomposition rate was observed at the first site, closest to the lake. At further sites with lower water temperatures, leaf litter decomposition rates decreased. Results observed through Hévíz canal demonstrated that higher water temperature accelerated the goldenrod decomposition dynamics, while the drift also impacted its efficiency.


PeerJ ◽  
2022 ◽  
Vol 10 ◽  
pp. e12747
Author(s):  
Peng Zan ◽  
Zijun Mao ◽  
Tao Sun

Litter quality and climate have been presumed to be the dominant factors regulating litter decomposition rates on broad spatial scales. However, the role of soil fauna on litter decomposition is poorly understood, despite the fact that it could strongly influence decomposition by fragmentation and subsequent modification of the activities of microorganisms.In this study, we carried out a meta-analysis on the effects of soil fauna on litter decomposition rates in Chinese forests, ranging from boreal to tropical forests, based on data from 20 studies. The effects of climatic factors on decomposition rate were assessed by comparing the contribution of soil fauna to litter decomposition from studies carried out at different latitudes.The degree of influence of the soil fauna was in the order tropical (200%) > subtropical (47%) > temperate forest (28%). Comparing the effect size of soil fauna, it was found that when soil fauna was excluded, the decomposition rate, calculated using Olson’s equation, was most affected in tropical forest (−0.77), while the litter decomposition rate both subtropical (−0.36) and temperate forest (−0.19) were also suppressed to varying degrees (P < 0.001). These results highlight that soil fauna could promote litter decomposition to different extents. Using stepwise multiple linear regression, the effect size of the soil fauna was negatively correlated with the cellulose and nitrogen concentrations of the initial litter material. In Chinese forests, litter decomposition rates were reduced, on average, by 65% when soil fauna was excluded. The impact of soil fauna on decomposition was shown to be closely related to climate and litter quality.


2020 ◽  
Vol 3 (1) ◽  
pp. 25
Author(s):  
David Candel-Pérez ◽  
J. Bosco Imbert ◽  
Maitane Unzu ◽  
Juan A. Blanco

The promotion of mixed forests represents an adaptation strategy in forest management to cope with climate change. The mixing of tree species with complementary ecological traits may modify forest functioning regarding productivity, stability, or resilience against disturbances. Litter decomposition is an important process for global carbon and nutrient cycles in terrestrial ecosystems, also affecting the functionality and sustainability of forests. Decomposition of mixed-leaf litters has become an active research area because it mimics the natural state of leaf litters in most forests. Thus, it is important to understand the factors controlling decomposition rates and nutrient cycles in mixed stands. In this study, we conducted a litter decomposition experiment in a Scots pine and European beech mixed forest in the province of Navarre (north of Spain). The effects of forest management (i.e., different thinning intensities), leaf litter types, and tree canopy on mass loss and chemical composition in such decomposing litter were analysed over a period of three years. Higher decomposition rates were observed in leaf litter mixtures, suggesting the existence of positive synergies between both pine and beech litter types. Moreover, a decomposition process was favoured under mixed-tree canopy patches. Regarding thinning treatments significant differences on decomposition rates disappeared at the end of the study period. Time influenced the nutrient concentration after the leaf litter incubation, with significant differences in the chemical composition between the different types of leaf litter. Higher Ca and Mg concentrations were found in beech litter types than in pine ones. An increase in certain nutrients throughout the decomposition process was observed due to immobilization by microorganisms (e.g., Mg in all leaf litter types, K only in beech leaves, P in thinned plots and under mixed canopy). Evaluating the overall response in mixed-leaf litters and the contribution of single species is necessary for understanding the litter decomposition and nutrient processes in mixed-forest ecosystems.


2021 ◽  
Vol 9 ◽  
Author(s):  
Ellen C. Kadeka ◽  
Frank O. Masese ◽  
David M. Lusega ◽  
Augustine Sitati ◽  
Benjamin N. Kondowe ◽  
...  

Expansion of agriculture is particularly worrying in tropical regions of the world, where native forests have been replaced by croplands and grasslands, with severe consequences for biodiversity conservation and ecosystem functioning. However, limited data exist on the effects of agriculture on the functioning of tropical streams. We conducted a leaf litter decomposition experiment in coarse- and fine-mesh litterbags using the three species of leaves (Eucalyptus globulus [non-native], Vernonia myriantha, and Syzygium cordatum [indigenous]) in three forested and agricultural streams to determine the effect of agriculture on instream leaf litter decomposition in headwater stream sites. We also examined the functional composition of macroinvertebrates in the streams through the contents of benthic kick samples. Agricultural streams had a less dense riparian canopy and smaller abundance of coarse organic particulate matter, and higher electric conductivity and suspended solids than forested streams. In terms of the effects of litter quality on decomposition rates, Vernonia had the fastest decomposition rates while Eucalyptus had the slowest in both forested and agricultural sites. Shredder invertebrates were less abundant in agricultural streams, and in both stream types, they were less diverse and abundant than other functional groups. Overall, leaf litter decomposition rates did not respond to agricultural land-use. The hypothesized negative effects of agriculture on organic matter processing were minimal and likely modulated by intact riparian zones along agricultural streams.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Slamet Santosa ◽  
Muhamad Ruslan Umar ◽  
Dody Priosambodo ◽  
Rizki Amalia Puji Santosa

Teak Tectona grandis Linn is still used as the main product in the form of wood, while other products, especially environmental services have not received much attention. This study analyzed biomass, carbon stocks and decomposition rate of leaf litter in teak plantations in city forest of Hasanuudin University, Makassar. The individual biomass of teak plants is calculated using the allometric equation, Y=0.11x ρ x D2.62. Carbon stocks were analyzed using a formulation, C=0.47xB. The leaf litter decomposition rate is expressed as the ratio of the remaining litter dry weight, with the formulation, X= (A-B)/A. The number of teak plants in 5 sample plots were 239 trees with an average stem diameter of 20.6cm and an average height of 9.02m. Total biomass in 5 sample plots was 51,712.61g. Carbon stock in 5 sample plots was 24,304.92g. Decomposition rate average of leaf litter of 24.4g during 60 days incubation. The existence of teak plantations is able to reduce CO2 in the atmosphere by as much as 89,199.06gCO2 and resulting in a decomposition rate of teak leaf litter 0.4g per day


2021 ◽  
Vol 10 (2) ◽  
pp. 233-242
Author(s):  
Muslimin Muslimin ◽  
Susiana Susiana ◽  
Aditya Hikmat Nugraha

Penelitian mengenai Produksi dan Laju Dekomposisi Serasah Mangrove Xylocarpus granatum dan Rhizophora apiculata di Perairan Busung dan Tanjung Unggat Pulau Bintan. Tujuan penelitian ini adalah untuk membandingkan produksi dan laju dekomposisi serasah mangrove Xylocarpus granatum dan Rhizophora apiculata di perairan Busung dan Tanjung Unggat, Pulau Bintan. Penelitian ini di laksanakan pada bulan Februari – Mei 2020 mengenai produksi dan laju dekomposisi serasah mangrove X. granatum dan R. apiculata di perairan Busung dan Tanjung Unggat Pulau Bintan. Penelitian ini bertujuan membandingkan produksi dan laju dekomposisi serasah mangrove X. granatum dan  R. apiculata. Penelitian ini dilakukan dengan penentuan lokasi, kemudian persiapan alat dan bahan dan dilanjutkan dengan pengambilan data kerapatan mangrove dan pengambilan data serasah serta laju dekomposisi. Hasil penelitian ditemukan 2 jenis mangrove di 2 stasiun yaitu X. granatum dan R. apiculata. Kerapatan total di Desa Busung berjumlah 2267 pohon/ha tergolong sangat padat dan masih dalam kondisi baik sedangkan kerapatan total di Tanjung Unggat berjumlah 1200 pohon/ha tergolong sedang dan masih dalam kondisi baik. Produksi serasah tertinggi yaitu terjadi pada Stasiun Busung yaitu R. apiculata 1.47 g/m2/hari dan X. ganatum 0.83 g/m2/hari dengan kerapatan yang padat dan untuk hasil terendah terjadi pada stasiun Tanjung Unggat yaitu R. apiculata 1.09 g/m2/hari dan X. granatum 0.65 g/m2/hari dengan kerapatan sedang. Laju dekomposisi serasah daun spesies X. granatum menunjukkan nilai 0.0192 dan Laju dekomposisi serasah daun spesies R. apiculata menunjukkan nilai 0.0203. Laju dekomposisi sersah daun terjadi penurunan yang sangat signifikan pada hari ke 14 yaitu dengan kisaran 0.04 – 0.06 gr/hr. Sedangkan pada hari ke-14 sampai hari ke-28 relatif  konstan, dengan kisaran 0.01 – 0.03 gr/hr. Research on the Production and Decomposition Rate of Xylocarpus granatum and Rhizophora apiculata Mangrove Litter in Busung and Tanjung Unggat Waters, Bintan Island. The purpose of this study was to compare the production and decomposition rate of mangrove litter from Xylocarpus granatum and Rhizophora apiculata in the waters of Busung and Tanjung Unggat, Bintan Island. This research was conducted in February - May 2020 regarding the production and decomposition rate of mangrove litter X. granatum and R. apiculata in the waters of Busung and Tanjung Unggat Bintan Island. This study aims to compare the production and decomposition rate of mangrove litter X. granatum and R. apiculata. This research was conducted by determining the location, then preparing the tools and materials, followed by collecting data on mangrove density and data collection of litter and decomposition rate. The results found 2 types of mangroves at 2 stations, namely X. granatum and R. apiculata. The total density in Busung Village was 2267 trees / ha which was classified as very dense and still in good condition, while the total density in Tanjung Unggat was 1200 trees / ha which was classified as moderate and still in good condition. The highest litter production occurred at Busung Station, namely R. apiculata 1.47 g/M2/day and X. granatum 0.83 g/m2 /day with a dense density and for the lowest yield occurred at Tanjung Unggat station, namely R. apiculata 1.09 g/m2/day and X. granatum 0.65 g/m2/day with moderate density. The leaf litter decomposition rate of species X. granatum showed a value of 0.0192 and the rate of decomposition of leaf litter of species R. apiculata showed a value of 0.0203. The decomposition rate of leaf litter decreased significantly on day 14, in the range of 0.04 - 0.06 gr/day. Meanwhile, on day 14 to day 28 it is relatively constant, with a range of 0.01 - 0.03 g/day.


2016 ◽  
Vol 62 (1) ◽  
pp. 178-190 ◽  
Author(s):  
Guodong Liu ◽  
Jinfang Sun ◽  
Kun Tian ◽  
Derong Xiao ◽  
Xingzhong Yuan

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