scholarly journals Impacts of multiple anthropogenic stressors on stream macroinvertebrate community composition and functional diversity

2020 ◽  
Author(s):  
Noel P. D. Juvigny‐Khenafou ◽  
Jeremy J. Piggott ◽  
David Atkinson ◽  
Yixin Zhang ◽  
Samuel J. Macaulay ◽  
...  
Keyword(s):  
Community Composition ◽  
Functional Diversity ◽  
Macroinvertebrate Community ◽  
Anthropogenic Stressors ◽  
Stream Macroinvertebrate

scholarly journals Contrasting Patterns of Functional Diversity in Coffee Root Fungal Communities Associated with Organic and Conventionally Managed Fields

2020 ◽  
Vol 86 (11) ◽  
Author(s):  
Elizabeth C. Sternhagen ◽  
Katie L. Black ◽  
Eliza D. L. Hartmann ◽  
W. Gaya Shivega ◽  
Peter G. Johnson ◽  
...  
Keyword(s):  
Community Composition ◽  
Functional Diversity ◽  
Plant Pathogens ◽  
Trophic Structure ◽  
High Throughput Sequencing ◽  
Fungal Communities ◽  
Its2 Region ◽  
Organic Management ◽  
Rhizosphere Fungi ◽  
Calcium And Magnesium

ABSTRACT The structure and function of fungal communities in the coffee rhizosphere are influenced by crop environment. Because coffee can be grown along a management continuum from conventional application of pesticides and fertilizers in full sun to organic management in a shaded understory, we used coffee fields to hold host constant while comparing rhizosphere fungal communities under markedly different environmental conditions with regard to shade and inputs. We characterized the shade and soil environment in 25 fields under conventional, organic, or transitional management in two regions of Costa Rica. We amplified the internal transcribed spacer 2 (ITS2) region of fungal DNA from coffee roots in these fields and characterized the rhizosphere fungal community via high-throughput sequencing. Sequences were assigned to guilds to determine differences in functional diversity and trophic structure among coffee field environments. Organic fields had more shade, a greater richness of shade tree species, and more leaf litter and were less acidic, with lower soil nitrate availability and higher soil copper, calcium, and magnesium availability than conventionally managed fields, although differences between organic and conventionally managed fields in shade and calcium and magnesium availability depended on region. Differences in richness and community composition of rhizosphere fungi between organic and conventionally managed fields were also correlated with shade, soil acidity, and nitrate and copper availability. Trophic structure differed with coffee field management. Saprotrophs, plant pathogens, and mycoparasites were more diverse, and plant pathogens were more abundant, in organic than in conventionally managed fields, while saprotroph-plant pathogens were more abundant in conventionally managed fields. These differences reflected environmental differences and depended on region. IMPORTANCE Rhizosphere fungi play key roles in ecosystems as nutrient cyclers, pathogens, and mutualists, yet little is currently known about which environmental factors and how agricultural management may influence rhizosphere fungal communities and their functional diversity. This field study of the coffee agroecosystem suggests that organic management not only fosters a greater overall diversity of fungi, but it also maintains a greater richness of saprotrophic, plant-pathogenic, and mycoparasitic fungi that has implications for the efficiency of nutrient cycling and regulation of plant pathogen populations in agricultural systems. As well as influencing community composition and richness of rhizosphere fungi, shade management and use of fungicides and synthetic fertilizers altered the trophic structure of the coffee agroecosystem.

scholarly journals Metal-induced shifts in benthic macroinvertebrate community composition in Andean high altitude streams

2010 ◽  
Vol 29 (12) ◽  
pp. 2761-2768 ◽  
Author(s):  
Raúl A. Loayza-Muro ◽  
Rafaela Elías-Letts ◽  
Jenny K. Marticorena-Ruíz ◽  
Edwin J. Palomino ◽  
Joost F. Duivenvoorden ◽  
...  
Keyword(s):  
High Altitude ◽  
Community Composition ◽  
Macroinvertebrate Community ◽  
Benthic Macroinvertebrate

Effects of forestry activities (clearfelling) on stream macroinvertebrate fauna in south-western Australia

1994 ◽  
Vol 45 (6) ◽  
pp. 963 ◽  
Author(s):  
IO Growns ◽  
JA Davis
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Western Australia ◽  
Macroinvertebrate Community ◽  
Total Abundance ◽  
Inorganic Solids ◽  
South West ◽  
Before And After ◽  
Stream Macroinvertebrate ◽  
Macroinvertebrate Fauna

The effects of forestry activities on macroinvertebrate community structure were examined in the headwaters of Carey Brook in the south-west of Australia. The fauna at four sites on an upland stream that ran through a logging coupe were compared, before and after clearfelling, with the fauna at four nearby undisturbed sites. Mean species richness and mean total abundance declined at the treatment sites relative to the control sites after the commencement of clearfelling activities. The composition of the macroinvertebrate fauna in the disturbed stream changed in comparison with that in the undisturbed sites after logging started but returned to the pre-logging composition after winter and spring rains had stopped. The observed changes in the macroinvertebrate fauna occurred during the periods of high loads of suspended inorganic solids at the treatment sites. The possible reasons for the observed results are discussed.

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