scholarly journals The impact of eucalypt on the leaf-associated aquatic hyphomycetes in Spanish streams

1997 ◽  
Vol 75 (6) ◽  
pp. 880-887 ◽  
Author(s):  
Eric Chauvet ◽  
Eric Fabre ◽  
Arturo Elósegui ◽  
Jesús Pozo
Keyword(s):  
Leaf Litter ◽  
Basque Country ◽  
Alnus Glutinosa ◽  
Fungal Species ◽  
Aquatic Hyphomycetes ◽  
Fungal Colonization ◽  
Important Species ◽  
Conidial Production ◽  
The Impact ◽  
Leaf Species

Aquatic hyphomycete assemblages on decomposing leaf litter of the exotic species Eucalyptus globulus Labill. were compared with those on the native riparian species Alnus glutinosa (L.) Gaertn. in three low-order streams of the Agüera watershed (Basque Country – Cantabria, Spain). These streams contrast by the importance of eucalypt in the riparian vegetation and by the nutrient contents in the water. Neither the total conidial production nor the number of fungal species differed between the two leaf species in any of the streams. Fungal colonization of eucalypt leaves appeared to be delayed by about 2 weeks, probably owing to their high content in inhibitory constituents. While Flagellospora curvula Ingold largely dominated pioneer assemblages on both leaf species, the second most important species, Lunulospora curvula Ingold, exhibited a preference for eucalypt. In the stream surrounded by eucalypt, the fungal diversity was surprisingly lower on eucalypt than on alder. In the stream with higher orthophosphate concentrations, the conidial production was similarly increased on both leaf species. The present data together with recent results from a similar investigation in Portugal suggest a minor impact of eucalypt on the activity and diversity of aquatic hyphomycete leaf-associated assemblages in southern European streams. Key words: aquatic hyphomycetes, eucalypt, alder, leaf litter, stream.

Fungal richness does not buffer the effects of streams salinization on litter decomposition

2021 ◽  
Vol 57 ◽  
pp. 5
Author(s):  
Janine Pereira da Silva ◽  
Aingeru Martínez ◽  
Ana Lúcia Gonçalves ◽  
Felix Bärlocher ◽  
Cristina Canhoto
Keyword(s):  
Mass Loss ◽  
Litter Decomposition ◽  
Fungal Biomass ◽  
Fungal Species ◽  
Aquatic Hyphomycetes ◽  
Negative Effects ◽  
Stream Functioning ◽  
Induced Changes ◽  
Sporulation Rate ◽  
The Impact

Freshwater salinization is a world-wide phenomenon threatening stream communities and ecosystem functioning. In these systems, litter decomposition is a main ecosystem-level process where fungi (aquatic hyphomycetes) play a central role linking basal resource and higher levels of food-web. The current study evaluated the impact of aquatic hyphomycete richness on leaf litter decomposition when subjected to salinization. In a microcosm study, we analysed leaf mass loss, fungal biomass, respiration and sporulation rate by fungal assemblages at three levels of species richness (1, 4, 8 species) and three levels of salinity (0, 8, 16 g NaCl L‑1). Mass loss and sporulation rate were depressed at 8 and 16 g NaCl L‑1, while fungal biomass and respiration were only negatively affected at 16 g L‑1. A richness effect was only observed on sporulation rates, with the maximum values found in assemblages of 4 species. In all cases, the negative effects of high levels of salinization on the four tested variables superimposed the potential buffer capacity of fungal richness. The study suggests functional redundancy among the fungal species even at elevated salt stress conditions which may guarantee stream functioning at extreme levels of salinity. Nonetheless, it also points to the possible importance of salt induced changes on fungal diversity and identity in salinized streams able to induce bottom-up effects in the food webs.

scholarly journals From Litterfall to Breakdown in Streams: A Review

2001 ◽  
Vol 1 ◽  
pp. 656-680 ◽  
Author(s):  
Manuela Abelho
Keyword(s):  
Organic Matter ◽  
Leaf Litter ◽  
Standing Stock ◽  
Fungal Colonization ◽  
Allochthonous Organic Matter ◽  
Factors Affecting ◽  
Breakdown Rates ◽  
And Storage ◽  
Leaf Species ◽  
Organic Matter Breakdown

This paper is a review of recent (≤10 years) information on litterfall, standing stock of benthic organic matter, breakdown rates, and fungal colonization of organic matter in streams. In some cases, recent research reinforces the findings of classic reference papers. In other cases, the additional knowledge provided by recent research introduces a higher variation in the processes analyzed. In many aspects, especially those concerning stream organic matter, the review is biased towards the temperate North American streams, reflecting the fact that most research was carried out there. However, during the 1990s European studies increased enormously, especially those related with instream processes, such as leaf litter decomposition. The first part of this review analyzes the origin of allochthonous organic matter to streams (litterfall, retention, and storage), and it provides data on the amounts estimated in different streams and on the methodology used in the studies. The second part analyzes the fate of detritus in streams: mechanisms of leaf breakdown, relative importance of fungi and bacteria, factors affecting the activity of microbial decomposers, and chemical changes of leaf litter during decomposition. A list of breakdown rates of several different leaf species is given, together with the methodology used, and the main characteristics of the incubation streams.

scholarly journals Diversity of fungi in decomposition process the Avicennia marina leaf litter at various level of salinity

2021 ◽  
Vol 886 (1) ◽  
pp. 012063
Author(s):  
Yunasfi ◽  
Derita ◽  
Ipanna Enggar Susetya ◽  
Rusdi Leidonald
Keyword(s):  
Species Diversity ◽  
Leaf Litter ◽  
Avicennia Marina ◽  
Diversity Indices ◽  
Fungal Species ◽  
Fungal Colonization ◽  
Isolation And Identification ◽  
Litter Bags ◽  
Litter Bag ◽  
Factors Affecting

Abstract Factors affecting the rate of the decomposition are animals and microorganisms such as worms, snails, bacteria, fungi etc. as well as environmental conditions, such as type of soil, pH and salinity of water, etc. This research was conducted at the Deli Belawan River and Forest Cultivation Laboratory, Medan, North Sumatra Sumatera. A study was undertaken to find out the effect of the salinity on : the number of species, the population, the species diversity and the frequency of colonization of the different species of fungi during the process of the composition of the A. marina leaf litter decomposition. The leaf litter of A. marina to be put in a litter bag that is 50 g and it’s 33 litter bags for each level of salinity totally. The level of salinity to be used such as < 10, 10 – 20, 20 – 30 and > 30 ppt. The time series to collect data were 0 (control), 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, and 165 days. The leaf litter of A. marina in a litter bag was taken from each salinity level that was three bags for each time. It was used for isolation and identification of the fungi. There were 21 fungal species isolated from the A. marina leaf litter before being decomposed and from those decomposed at < 10, 10 – 20, 20 – 30 and > 30 ppt. The highest population was found in the leaf litter before being decomposed with an average of 1.6 × 103 cfu/ml. The Species Diversity Indices of the fungi isolated from the leaf litter at < 10, 10 – 20, 20 – 30, and > 30 ppt were 1.96, 1.86, 1.75 and 1,50. The frequency of the fungal colonization ranged from 9.1 to 100 %.

scholarly journals Stream ecosystems respond to riparian invasion by Japanese knotweed (Fallopia japonica)

2007 ◽  
Vol 64 (9) ◽  
pp. 1273-1283 ◽  
Author(s):  
Antoine Lecerf ◽  
Denise Patfield ◽  
Anatole Boiché ◽  
Miira P Riipinen ◽  
Eric Chauvet ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Aquatic Hyphomycetes ◽  
Stream Ecosystems ◽  
Japanese Knotweed ◽  
Litter Breakdown ◽  
Breakdown Rate ◽  
Fallopia Japonica ◽  
Leaf Litter Breakdown ◽  
Plant Invaders ◽  
The Impact

There are growing concerns about the rapid spread of exotic plants into riparian zones, yet little information is currently available on their influence on stream ecosystems. This study assessed the impact of riparian invasion by Japanese knotweed (Fallopia japonica), an aggressive invader, on leaf litter breakdown and its associated biota (aquatic hyphomycete fungi and benthic invertebrates) in heterotrophic, low-order streams in The Pennines (England) and the Pyrenees (France). Our results suggest that leaf consumers (aquatic hyphomycetes and invertebrate shredders) can readily use knotweed leaf litter even in stream sites where it was not previously present. However, aquatic hyphomycete and invertebrate assemblages differed between stream sites with and without knotweed. Leaf litter breakdown rate and relative abundance of large invertebrate shredders (mainly Trichoptera) were enhanced in the Pyrenean invaded site, whose channel contained a high proportion of knotweed leaf litter, whereas no such effects were observed in The Pennines, possibly because of the less extensive knotweed invasion. Alteration of riparian vegetation by plant invaders could therefore increasingly influence instream community and ecological functions as the severity of invasion rises.

scholarly journals Microbial Community Dynamics of Soybean (Glycine max) Is Affected by Cropping Sequence

2021 ◽  
Vol 12 ◽  
Author(s):  
Ayooluwa J. Bolaji ◽  
Joey C. Wan ◽  
Christopher L. Manchur ◽  
Yvonne Lawley ◽  
Teresa R. de Kievit ◽  
...  
Keyword(s):  
Species Richness ◽  
Microbial Community ◽  
Community Dynamics ◽  
Rhizosphere Soil ◽  
Fungal Species ◽  
Bulk Soil ◽  
Important Species ◽  
Microbial Community Dynamics ◽  
The Impact ◽  
Crop Sequence

The microbial composition of the rhizosphere soil could be an important determinant of crop yield, pathogen resistance, and other beneficial attributes in plants. However, little is known about the impact of cropping sequences on microbial community dynamics, especially in economically important species like soybean. Using 2-year crop sequences of corn-soybean, canola-soybean, and soybean-soybean, we investigated how crops from the previous growing season influenced the structure of the microbiome in both the bulk soil and soybean rhizosphere. A combination of marker-based Illumina sequencing and bioinformatics analyses was used to show that bacterial species richness and evenness in the soybean rhizosphere soil were similar following canola and soybean compared to a previous corn sequence. However, fungal species richness and evenness remained unaffected by crop sequence. In addition, bacterial and fungal species diversity in both the bulk and soybean rhizosphere soil were not influenced by crop sequence. Lastly, the corn-soybean sequence significantly differed in the relative abundance of certain bacterial and fungal classes in both the soybean rhizosphere and bulk soil. While canola-soybean and a continuous soybean sequence did not, suggesting that a preceding corn sequence may reduce the occurrence of overall bacterial and fungal community members. For the present study, crop sequence impacts bacterial diversity and richness in both the bulk soil and soybean rhizosphere soil whereas fungal diversity and richness are resilient to crop sequence practices. Together, these findings could help drive decision making for annual crop and soil management practices.

scholarly journals Laurel Wilt: Current and Potential Impacts and Possibilities for Prevention and Management

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 181
Author(s):  
Rabiu O. Olatinwo ◽  
Stephen W. Fraedrich ◽  
Albert E. Mayfield
Keyword(s):  
United States ◽  
Tree Mortality ◽  
The United States ◽  
Persea Americana ◽  
Laurel Wilt ◽  
Important Species ◽  
Invasive Insects ◽  
Raffaelea Lauricola ◽  
Redbay Ambrosia Beetle ◽  
The Impact

In recent years, outbreaks of nonnative invasive insects and pathogens have caused significant levels of tree mortality and disturbance in various forest ecosystems throughout the United States. Laurel wilt, caused by the pathogen Raffaelea lauricola (T.C. Harr., Fraedrich and Aghayeva) and the primary vector, the redbay ambrosia beetle (Xyleborus glabratus Eichhoff), is a nonnative pest-disease complex first reported in the southeastern United States in 2002. Since then, it has spread across eleven southeastern states to date, killing hundreds of millions of trees in the plant family Lauraceae. Here, we examine the impacts of laurel wilt on selected vulnerable Lauraceae in the United States and discuss management methods for limiting geographic expansion and reducing impact. Although about 13 species belonging to the Lauraceae are indigenous to the United States, the highly susceptible members of the family to laurel wilt are the large tree species including redbay (Persea borbonia (L.) Spreng) and sassafras (Sassafras albidum (Nutt.) Nees), with a significant economic impact on the commercial production of avocado (Persea americana Mill.), an important species native to Central America grown in the United States. Preventing new introductions and mitigating the impact of previously introduced nonnative species are critically important to decelerate losses of forest habitat, genetic diversity, and overall ecosystem value.

scholarly journals Insect herbivory facilitates the establishment of an invasive plant pathogen

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Martin M. Gossner ◽  
Ludwig Beenken ◽  
Kirstin Arend ◽  
Dominik Begerow ◽  
Derek Peršoh
Keyword(s):  
Invasive Plant ◽  
Pathogenic Fungus ◽  
Feeding Activity ◽  
Insect Herbivory ◽  
Forest Health ◽  
Mechanical Damage ◽  
Pathogenic Fungi ◽  
Fungal Colonization ◽  
Feeding Damage ◽  
The Impact

AbstractPlants can be severely affected by insect herbivores and phytopathogenic fungi, but interactions between these plant antagonists are poorly understood. We analysed the impact of feeding damage by the abundant herbivore Orchestes fagi on infection rates of beech (Fagus sylvatica) leaves with Petrakia liobae, an invasive plant pathogenic fungus. The fungus was not detected in hibernating beetles, indicating that O. fagi does not serve as vector for P. liobae, at least not between growing seasons. Abundance of the fungus in beech leaves increased with feeding damage of the beetle and this relationship was stronger for sun-exposed than for shaded leaves. A laboratory experiment revealed sun-exposed leaves to have thicker cell walls and to be more resistant to pathogen infection than shaded leaves. Mechanical damage significantly increased frequency and size of necroses in the sun, but not in shade leaves. Our findings indicate that feeding damage of adult beetles provides entry ports for fungal colonization by removal of physical barriers and thus promotes infection success by pathogenic fungi. Feeding activity by larvae probably provides additional nutrient sources or eases access to substrates for the necrotrophic fungus. Our study exemplifies that invasive pathogens may benefit from herbivore activity, which may challenge forest health in light of climate change.

scholarly journals Effectiveness of Three Post-Harvest Rehabilitation Treatments for Runoff and Sediment Reduction on Skid Trails in the Hyrcanian Forests

2020 ◽  
Vol 41 (2) ◽  
pp. 309-324
Author(s):  
Meghdad Jourgholami ◽  
Masoumeh Ahmadi ◽  
Farzam Tavankar ◽  
Rodolfo Picchio
Keyword(s):  
Leaf Litter ◽  
Sediment Yield ◽  
Rainfall Intensity ◽  
Regression Equations ◽  
Negative Effects ◽  
Diverse Range ◽  
Straw Mulch ◽  
The Impact ◽  
Different Levels ◽  
Runoff And Sediment Yield

Ground-based skidding operations can lead to soil compaction and displacement, which could cause negative effects on forest soil. Hence, some efforts such as forestry best management practices (BMPs) must be implemented in the prone area to mitigate these possible impacts. Several materials and treatments have been adopted to suppress these adverse effects by increasing the ground cover. However, the effects of mulch treatments on runoff and sediment yield are inconclusive with a diverse range of effectiveness. For these reasons, in this research mulch treatments were tested as to determine how the application of organic mulch amendments such as straw and leaf litter and contour-felled logs would alleviate the runoff and sediment yield on machine operating trails and ensure successful hillslope stabilization. The aims of the study were to analyse and compare the effectiveness of leaf litter (LM) and straw mulch (SM) rate and different distances of contour-felled logs (CFL) to mitigate the runoff and sediment yield, and examine the impact of rainfall intensity on effectiveness of litter mulch, straw mulch, and contour-felled logs. Totally, 30 bounded runoff plots in the machine operating trails and four treatments including litter mulch (LMR1: 0.62, LMR2: 1.24, and LMR3: 1.86 kg m-2), straw mulch (SMR1: 0.45, SMR2: 0.92, and SMR3: 1.34 kg m-2), contour-felled logs (CFL10: 10, CFL20: 20, and CFL30: 30 m), and untreated area were established in triplicate with 4 m width and 100 m length. During the study period, the runoff and sediment yield in the untreated trails (U) were 2.36 mm and 11.84 g m-2. Straw (from 41.5 to 60.6%) and litter mulch (from 38.1 to 55.1%), and contour-felled logs treatments (from 70.8 to 88.1%) significantly decreased the runoff, compared to U treatment. Results show that mulch treatments with three different levels of Litter Mulch Rate, LMR1, LMR2, and LMR3 decreased mean sediment by 46.6, 64.0 and 71.8%, in the treatments with three different levels of Straw Mulch Rate, SMR1, SMR2, and SMR3 decreased mean sediment by 42.9, 62.1, and 69.9%, and in the treatments with three different distances of Contour-Felled Logs, CFL10, CFL20, and CFL30 decreased mean sediment by 90.6, 94.7 and 88.3% comparing to U, respectively. The relationships of the runoff and sediment responses to increasing mulching rate of litter and straw followed as negative logarithmic curves, but the decreasing-increasing trends were observed in runoff and sediment yield as the distance between contour-felled logs increased from 10 to 30 m. Polynomial regression equations were developed for predicting the runoff and sediment yield as a function of the application rate of litter and straw mulch and the distance between contour-felled logs, and rainfall intensity. We concluded that contour-felled logs treatment was more effective than both litter and straw mulch to mitigate the runoff, runoff coefficient, and sediment yield on machine operating trails. As a management measure, it could be possible to propose that the contour-felled logs with a distance of 20 m be prescribed to protect the machine operating trails from the negative effects of surface waterflow.

scholarly journals Population changes in rattail species on the Chatham Rise

2021 ◽  
Author(s):  
◽  
Kathleen Large
Keyword(s):  
Maximum Likelihood ◽  
Stock Assessment ◽  
Production Model ◽  
Likelihood Method ◽  
Model Parameters ◽  
Important Species ◽  
Surplus Production ◽  
Surplus Production Model ◽  
Abundance Indices ◽  
The Impact

<p>The aim of this project was to conduct a stock assessment to determine the population dynamic characteristics of rattail species taken as bycatch in the hoki, hake and ling fishery on the Chatham Rise. No quantitative assessment of the current size of rattail populations , and how these may have changed over time, has been carried out before. There is interest in the need to quantify the impact of commercial fishing on the rattail populations, as rattails (Macrouridae family) are considered to be an ecologically important species complex in the deep ocean, and there may be the potential for the development of a commercial fishery based on their value as processed fishmeal. The minimum data required for a stock assessment are an abundance index and a catch history. Abundance indices are available for over 20 species of rattail produced from scientific surveys conducted annually on the Chatham Rise since 1992. Catch histories for individual rattail species in the same area are not available. A method was developed to reconstruct commercial catches of rattails from commercial effort data and survey catch and effort data. A surplus production model was fitted to the reconstructed catch data and survey abundance indices, using maximum likelihood and Bayesian methods to estimate model parameters and uncertainty. A surplus production model has two components: an observation model for abundance indices and a process model for population dynamics. Maximum likelihood estimation was applied to a model that specified errors for the observations only, and this produced estimates that had wide confidence intervals. A Bayesian approach was then taken to fit a statespace version of the model that incorporates errors associated with the observation and process models. While the Bayesian method produced more plausible parameter estimates (in comparison to the maximum likelihood method) and parameter uncertainty was reduced, our analysis indicated the posterior estimates were highly sensitive to the specification of different priors. There may be several reasons for these results, including: the small number of observations, lack of contrast in the data and mis-specification of the model. Meaningful estimates of the absolute size of rattail populations are not possible with these results, where estimates can vary by orders of magnitude depending on prior specification. This implies that more work needs to be done to develop more effective methods that can be used to help inform decisions regarding the management of these fish populations. Improving data collection, investigating informative priors and extending/respecifying the model are considered worthwhile avenues of future work to improve stock assessments of rattails.</p>

Sign in / Sign up

Export Citation Format

Share Document