scholarly journals Post-fire consequences for leaf breakdown in a tropical stream

2019 ◽  
Vol 31 ◽  
Author(s):  
Renan de Souza Rezende ◽  
Cristiano Queiroz de Albuquerque ◽  
Andrezza Sayuri Victoriano Hirota ◽  
Paulo Fernandes Roges Souza Silva ◽  
Ricardo Keichi Umetsu ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Fungal Biomass ◽  
Mesh Size ◽  
Fire Effects ◽  
Dry Mass ◽  
Tropical Stream ◽  
Fire Event ◽  
Litter Bags ◽  
Fine Mesh ◽  
Post Fire Effects

Abstract Aim Wildfire is a natural pulsed disturbance in landscapes of the Savannah Biome. This study evaluates short-term post-fire effects on leaf litter breakdown, the invertebrate community and fungal biomass of litter from three different vegetal species in a tropical stream. Methods Senescent leaves of Inga laurina, Protium spruceanum and Rircheria grandis (2 ± 0.1 g dry mass) were individually placed in litter bags (30 × 30 cm: 10 mm coarse mesh and 0.5 mm fine mesh) and submerged in the study stream before and after fire. Replicate bags (n = 4; individually for each species, sampling time, fire event and mesh size) were then retrieved after 20 and 40 days and washed to separate the invertebrates before fire event and again immediately after fire. Disks were cut from leaves to determine ash-free dry mass, while the remaining material was oven-dried to determine dry mass. Results The pre-fire mean decomposition coefficient (k = -0.012 day-1) was intermediate compared to that reported for other savannah streams, but post-fire it was lower (k = -0.007 day-1), due to decreased allochthonous litter input and increased autochthones production. Intermediate k values for all qualities of litter post-fire may indicate that fire is equalizing litter quality in the stream ecosystem. The abundance of scrapers was found to be more important than fungal biomass or shredder abundance, probably due to their functioning in leaf fragmentation while consuming periphyton growing on leaf litter. Conclusions Theses results indicate that fire can modify the relationships within decomposer communities in tropical stream ecosystems.

scholarly journals Experimental manipulation of leaf litter colonization by aquatic invertebrates in a third order tropical stream

2015 ◽  
Vol 75 (2) ◽  
pp. 405-413 ◽  
Author(s):  
VS. Uieda ◽  
EM. Carvalho
Keyword(s):  
Leaf Litter ◽  
Canopy Cover ◽  
Dry Mass ◽  
Experimental Manipulation ◽  
Wet Season ◽  
Tropical Stream ◽  
Local Fauna ◽  
Litter Bags ◽  
Leaf Type ◽  
Closed Area

Through a manipulative experiment, the colonization of leaf litter by invertebrates was investigated in two sections of a tropical stream (spatial scale) that differed in function of the canopy cover, one with the presence (closed area) and another without riparian vegetation (open area), during one month of the dry and one of the wet season (temporal scale). The work aimed to verify differences related to four variables: season, canopy cover, leaf type and leaf condition. Litter bags containing arboreal and herbaceous leaves (leaf type variable), non-conditioned and preconditioned (leaf condition variable) were placed at the bottom of the stream in each area (canopy cover variable) and season (dry and wet), and removed after 13-day colonization. The analysis of the remaining litter dry mass per leaf bag emphasizes differences related mainly to seasonality, canopy cover and leaf type, although leaf condition was also important when combined with those three factors. Comparing the abundance of invertebrates per treatment, there was a tendency of high predominance of Chironomidae during the dry season and greater taxa diversity and evenness during the wet season, when the water flow increase could alter the availability of microhabitats for local fauna. Even though canopy cover alone was not a significant source of variation in the abundance of invertebrates, the results showed a tendency of a combined effect of canopy cover with seasonality and leaf condition.

Connecting the litterfall temporal dynamics and processing of coarse particulate organic matter in a tropical stream

2017 ◽  
Vol 68 (7) ◽  
pp. 1260 ◽  
Author(s):  
Aurea Luiza Lemes da Silva ◽  
Leonardo Kleba Lisboa ◽  
Ana Emília Siegloch ◽  
Mauricio Mello Petrucio ◽  
José Francisco Gonçalves Júnior
Keyword(s):  
Microbial Biomass ◽  
Leaf Litter ◽  
Fungal Biomass ◽  
Temporal Dynamics ◽  
Dry Mass ◽  
Aquatic Invertebrate ◽  
Wet Season ◽  
Tropical Stream ◽  
Breakdown Rates ◽  
Decomposer Community

We collected leaf litter monthly and analysed how the temporal dynamics of litterfall affect the breakdown rates, microbial and fungal biomass and aquatic invertebrate community in a tropical stream in southern Brazil. The results showed that total annual litterfall varied over time and was negatively associated with rainfall. Litter fell mostly in the spring months, but other peaks occurred throughout the year. In all, 122 tree species were identified; however, only seven represented >70% of the total of leaf litter vertical input. Leaf decomposition was higher in February and April (wet, warm months) than during the wet season. Fungal biomass was high in decomposing leaves (460±28μgg–1 of ash-free dry mass, AFDM), with a maximum of 655μgg–1 AFDM in July. Microbial biomass in decomposing leaves was lower (326±27 nmol g–1 AFDM), with a maximum of 504 nmol g–1 AFDM in October. Monthly variability in the fungal and microbial biomass and aquatic invertebrate colonisation were associated with litter quality. The results suggested that litterfall is the result of regional environmental factors and characteristics of the riparian vegetation and that modifications in the quality, quantity and timing of the delivery of litter input to the stream affect activity in the decomposer community, which then affects monthly litter-breakdown rates.

How energy crops (Maize, Field grass, Cup Plant) affect soil microarthropods and their decomposition services

2020 ◽  
Author(s):  
Pascaline Dioh Lobe ◽  
Stefan Schrader
Keyword(s):  
Mesh Size ◽  
Plant Litter ◽  
Energy Crops ◽  
Agricultural Landscapes ◽  
Ecosystem Functions ◽  
Soil Biodiversity ◽  
Litter Bags ◽  
Soil Microarthropods ◽  
Fine Mesh ◽  
Maize Field

<p>Energy crops are grown at low cost and low maintenance used in making biofuels, such as bioethanol, or combusted to generate electricity or heat. Production of energy crops as an alternative to fossil fuels will help to reduce CO<sub>2</sub> emission, thus leading to large scale changes in agricultural landscapes. Increase in the cultivation of annual energy crops such as maize (<em>Zea mays</em>) is assumed to decrease biodiversity in the agrarian landscape. This may lead to changes in soil properties, thereby affecting the soil biodiversity and its ecosystem functions and services like for instance soil microarthropod communities and their contribution to decomposition of plant litter. Perennial crops such as field grass (a mixture of Festulolium,  <em>Dactylis glomerate, Loliuim perenne, Festuca pratensis and Festuca arundinacea</em>) and cup plant (<em>Silphium perfoliatum</em>) are assumed to protect and promote soil biodiversity through less intensive management. The relationship between decomposer diversity and ecosystem functioning is little understood. So far, the role of soil microarthropods in decomposition is the most disputed aspect due to scarce empirical data.</p><p>The main aim of this field study was to assess the effect of soil microarthropods on litter of maize, field grass and cup plant, via decomposition using litter bags with 2 different mesh sizes (0.02 mm and 0.5 mm) for a period of 3 months during the vegetation period. At the end of the experiment, the decomposition rate was higher in cup plant followed by maize and field grass in the coarse mesh size, and higher in the cup plant followed by field grass and maize in the fine mesh size. A total of 55,464 soil microarthropods (73% mites, 25% collembola and 2% others) were extracted from the litter bags. The diversity and abundance of soil microarthropods was higher under cup plant cultivation followed by field grass and maize.</p>

Aggregation of Lepidostomatidae in small mesh size litter-bags: implication to the leaf litter decomposition process

2008 ◽  
Vol 17 (4) ◽  
pp. 417-421 ◽  
Author(s):  
Aung Nanda ◽  
Takashi Asaeda ◽  
Takeshi Fujino ◽  
Kian Siong ◽  
Takashi Nakajima
Keyword(s):  
Leaf Litter ◽  
Litter Decomposition ◽  
Mesh Size ◽  
Decomposition Process ◽  
Leaf Litter Decomposition ◽  
Litter Bags

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.

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.

scholarly journals Can anthropic fires affect epigaeic and hypogaeic Cerrado ant (Hymenoptera: Formicidae) communities in the same way?

2016 ◽  
Vol 64 (1) ◽  
pp. 95 ◽  
Author(s):  
Ernesto Oliveira Canedo-Júnior ◽  
Rafael Gonçalves Cuissi ◽  
Nelson Henrique De Almeida Curi ◽  
Guilherme Ramos Demetrio ◽  
Chaim José Lasmar ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Recovery Time ◽  
Fire Effects ◽  
Control Area ◽  
Control Group ◽  
Ant Communities ◽  
Fire Event ◽  
Biological Communities ◽  
One Year

Fire occurrences are a common perturbation in Cerrado ecosystems, and may differently impact the local biodiversity. Arthropods are one of the taxa affected by fires, and among them, ants are known as good bioindicators. We aimed to evaluate the effect of anthropic fires on epigaeic and hypogaeic ant communities (species richness and composition) in Cerrado areas with different post-fire event recovery periods. We conducted the study in four Cerrado areas during two weeks of 2012 dry season: one unburned and three at different post-fire times (one month, one and two years). We sampled ants with pitfall traps in epigaeic and hypogaeic microhabitats. We collected 71 ant morpho-species from 25 genera. In the epigaeic microhabitat we sampled 56 morpho-species and 42 in the hypogaeic microhabitat. The area with the shortest recovery time presented lower epigaeic ant species richness (4.3 ± 2.00) in comparison to the other areas (8.1 ± 2.68 species on one year area; 10.3 ± 2.66 species on two years area; 10.4 ± 2.31 species on control area), but recovery time did not affect hypogaeic ant species richness. Regarding ant species composition, fire did not directly affect hypogaeic ant species, which remained the same even one month after fire event. However, two years were not enough to reestablish ant species composition in both microhabitats in relation to our control group samples. Our study is the first to assess anthropic fire effects upon epigaeic and hypogaeic ants communities; highlighting the importance of evaluating different microhabitats, to more accurately detect the effects of anthropic disturbances in biological communities. We concluded that ant communities are just partially affected by fire occurrences, and epigaeic assemblages are the most affected ones in comparison to hypogaeic ants. Furthermore the study provides knowledge to aid in the creation of vegetation management programs that allow Cerrado conservation.

scholarly journals No Difference in Instream Decomposition Among Upland Agricultural and Forested Streams in Kenya

2021 ◽  
Vol 9 ◽  
Author(s):  
Ellen C. Kadeka ◽  
Frank O. Masese ◽  
David M. Lusega ◽  
Augustine Sitati ◽  
Benjamin N. Kondowe ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Litter Decomposition ◽  
Agricultural Land ◽  
Leaf Litter Decomposition ◽  
Limited Data ◽  
Negative Effects ◽  
Decomposition Rates ◽  
Tropical Regions ◽  
Fine Mesh ◽  
Agricultural Streams

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.

scholarly journals Contributions of organic matter and nutrients via leaf litter in an urban tropical dry forest fragment

2018 ◽  
Vol 66 (2) ◽  
pp. 571 ◽  
Author(s):  
Jeiner Castellanos-Barliza ◽  
Juan Diego León-Peláez ◽  
Rosalba Armenta-Martínez ◽  
Willinton Barranco-Pérez ◽  
William Caicedo-Ruíz
Keyword(s):  
Organic Matter ◽  
Leaf Litter ◽  
Tropical Dry Forest ◽  
Soil Surface ◽  
Dry Forest ◽  
Litter Production ◽  
Forest Fragment ◽  
Litter Bags ◽  
One Year ◽  
Degraded Ecosystems

The litterfall and decomposition represent the main transfer of organic matter and nutrients from the vegetation to the soil surface and determine positive trajectories in the process of rehabilitating and restoring degraded ecosystems. The aim of this study was to evaluate the contributions of organic materials and nutrients through the characterization of fine litter in an urban dry forest fragment. Litter production was monitored for one year by collecting 29 traps (0.5 m2). To evaluate leaf nutrient resorption, green leaves were collected from 5-10 individuals that represented the dominant tree species. Litter-bags (20 x 20 cm, 2 mm pore) were used for six months to evaluate the decomposition of leaf litter. Annual fine litter production was found to be 8 574 kg ha-1, with the Cordia alba species contributing the most leaf litter (1 134 kg ha-1) and nutrients (N: 6.16; P: 0.21; Ca: 4.72; Mg: 0.47; K: 1.27 kg ha-1). Decomposition rates (k constant) followed the decreasing order: C. alba (k: 4.6) > Machaerium milleflorum (k: 3.5). M. milleflorum and Albizia niopoides presented a pattern of rapid N and P release in the first 30 days, with more than 80 % and 60 % released from M. milleflorum and C. alba, respectively, by the end of the experiment. The litterfall monitoring carried out in this urban dry forest fragment revealed some important aspects of the functioning of an ecosystem as seriously threatened as the tropical dry forest. Rev. Biol. Trop. 66(2): 571-585. Epub 2018 June 01. 

Experimental and Numerical Plastic Response and Failure of Laterally Impacted Rectangular Plates

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
B. Liu ◽  
R. Villavicencio ◽  
C. Guedes Soares
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Failure Modes ◽  
Mesh Size ◽  
Plastic Behavior ◽  
Finite Element Models ◽  
Rectangular Plates ◽  
Marine Structures ◽  
Fine Mesh ◽  
The Impact

Experimental and numerical results of drop weight impact test are presented on the plastic behavior and fracture of rectangular plates stuck laterally by a mass with a hemispherical indenter. Six specimens were tested in order to study the influence of the impact velocity and the diameter of the indenter. The impact scenarios could represent abnormal actions on marine structures, such as ship collision and grounding or dropped objects on deck structures. The tests are conducted on a fully instrumented impact tester machine. The obtained force-displacement response is compared with numerical simulations, performed by the LS-DYNA finite element solver. The simulations aim at proposing techniques for defining the material and restraints on finite element models which analyze the crashworthiness of marine structures. The mesh size and the critical failure strain are predicted by numerical simulations of the tensile tests used to obtain the mechanical properties of the material. The experimental boundary conditions are modeled in order to represent the reacting forces developed during the impact. The results show that the critical impact energy until failure is strongly sensitive to the diameter of the striker. The shape of the failure modes is well predicted by the finite element models when a relatively fine mesh is used. Comments on the process of initiation and propagation of fracture are presented.

Sign in / Sign up

Export Citation Format

Share Document