CHEMISTRY AS AN UNDERLYING FORCE IN ECOSYSTEM INTERACTIONS

Keynote paper presented at the International Leucaena Conference, 1‒3 November 2018, Brisbane, Queensland, Australia.This review describes the history of research in Leucaena leucocephala (leucaena) feeding systems carried out by the National Institute of Agricultural Technology (INTA) over the last 5 decades and discusses the main limitations resulting in poor adoption in Argentina. Leucaena was introduced in the subtropical region of the north of the country in the late 1960s and early 1970s. Since then, INTA has conducted research to evaluate forage and animal productivity, leucaena accessions, rhizobial strains, contribution to soil carbon and total nitrogen and density effects on competition and other ecosystem interactions in silvopastoral systems. In spite of the convincing research results showing the excellent potential of leucaena to increase forage quality and animal production in suitable areas, there has been poor adoption of this forage tree legume on a broad scale.

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Enantiomers of Carbohydrates and Their Role in Ecosystem Interactions: A Review

Symmetry ◽

10.3390/sym12030470 ◽

2020 ◽

Vol 12 (3) ◽

pp. 470 ◽

Cited By ~ 5

Author(s):

Lea Lojkova ◽

Valerie Vranová ◽

Pavel Formánek ◽

Ida Drápelová ◽

Martin Brtnicky ◽

...

Keyword(s):

Abiotic Stress ◽

Plant Nutrition ◽

Current Knowledge ◽

Genetic Regulation ◽

Future Research ◽

Knowledge Gaps ◽

Research Knowledge ◽

Critical Knowledge ◽

Ecosystem Interactions ◽

Plant Compounds

D- and most L-enantiomers of carbohydrates and carbohydrate-containing compounds occur naturally in plants and other organisms. These enantiomers play many important roles in plants including building up biomass, defense against pathogens, herbivory, abiotic stress, and plant nutrition. Carbohydrate enantiomers are also precursors of many plant compounds that significantly contribute to plant aroma. Microorganisms, insects, and other animals utilize both types of carbohydrate enantiomers, but their biomass and excrements are dominated by D-enantiomers. The aim of this work was to review the current knowledge about carbohydrate enantiomers in ecosystems with respect to both their metabolism in plants and occurrence in soils, and to identify critical knowledge gaps and directions for future research. Knowledge about the significance of D- versus L-enantiomers of carbohydrates in soils is rare. Determining the mechanism of genetic regulation of D- and L-carbohydrate metabolism in plants with respect to pathogen and pest control and ecosystem interactions represent the knowledge gaps and a direction for future research.

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Using CESM-RESFire to understand climate–fire–ecosystem interactions and the implications for decadal climate variability

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-995-2020 ◽

2020 ◽

Vol 20 (2) ◽

pp. 995-1020 ◽

Cited By ~ 3

Author(s):

Yufei Zou ◽

Yuhang Wang ◽

Yun Qian ◽

Hanqin Tian ◽

Jia Yang ◽

...

Keyword(s):

Climate Change ◽

Future Climate Change ◽

Radiative Effect ◽

Aerosol Cloud ◽

Fire Activity ◽

Climate Systems ◽

Aerosol Cloud Interactions ◽

In Fire ◽

Ecosystem Interactions ◽

Feedback Pathways

Abstract. Large wildfires exert strong disturbance on regional and global climate systems and ecosystems by perturbing radiative forcing as well as the carbon and water balance between the atmosphere and land surface, while short- and long-term variations in fire weather, terrestrial ecosystems, and human activity modulate fire intensity and reshape fire regimes. The complex climate–fire–ecosystem interactions were not fully integrated in previous climate model studies, and the resulting effects on the projections of future climate change are not well understood. Here we use the fully interactive REgion-Specific ecosystem feedback Fire model (RESFire) that was developed in the Community Earth System Model (CESM) to investigate these interactions and their impacts on climate systems and fire activity. We designed two sets of decadal simulations using CESM-RESFire for present-day (2001–2010) and future (2051–2060) scenarios, respectively, and conducted a series of sensitivity experiments to assess the effects of individual feedback pathways among climate, fire, and ecosystems. Our implementation of RESFire, which includes online land–atmosphere coupling of fire emissions and fire-induced land cover change (LCC), reproduces the observed aerosol optical depth (AOD) from space-based Moderate Resolution Imaging Spectroradiometer (MODIS) satellite products and ground-based AErosol RObotic NETwork (AERONET) data; it agrees well with carbon budget benchmarks from previous studies. We estimate the global averaged net radiative effect of both fire aerosols and fire-induced LCC at -0.59±0.52 W m−2, which is dominated by fire aerosol–cloud interactions (-0.82±0.19 W m−2), in the present-day scenario under climatological conditions of the 2000s. The fire-related net cooling effect increases by ∼170 % to -1.60±0.27 W m−2 in the 2050s under the conditions of the Representative Concentration Pathway 4.5 (RCP4.5) scenario. Such considerably enhanced radiative effect is attributed to the largely increased global burned area (+19 %) and fire carbon emissions (+100 %) from the 2000s to the 2050s driven by climate change. The net ecosystem exchange (NEE) of carbon between the land and atmosphere components in the simulations increases by 33 % accordingly, implying that biomass burning is an increasing carbon source at short-term timescales in the future. High-latitude regions with prevalent peatlands would be more vulnerable to increased fire threats due to climate change, and the increase in fire aerosols could counter the projected decrease in anthropogenic aerosols due to air pollution control policies in many regions. We also evaluate two distinct feedback mechanisms that are associated with fire aerosols and fire-induced LCC, respectively. On a global scale, the first mechanism imposes positive feedbacks to fire activity through enhanced droughts with suppressed precipitation by fire aerosol–cloud interactions, while the second one manifests as negative feedbacks due to reduced fuel loads by fire consumption and post-fire tree mortality and recovery processes. These two feedback pathways with opposite effects compete at regional to global scales and increase the complexity of climate–fire–ecosystem interactions and their climatic impacts.

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Geoheritage in Deltaic Environments: Classification Notes, Case Example, and Geopark Implication

Environments ◽

10.3390/environments6020018 ◽

2019 ◽

Vol 6 (2) ◽

pp. 18 ◽

Cited By ~ 6

Author(s):

Anna Mikhailenko ◽

Dmitry Ruban

Keyword(s):

River Delta ◽

Anthropogenic Sources ◽

Full Spectrum ◽

River Deltas ◽

Geological Features ◽

Don River ◽

The Rich ◽

Ecosystem Interactions ◽

Geological Phenomenon

River deltas boast ecosystem richness, but their efficient conservation and management require consideration of the full spectrum of natural phenomena, including those which are geological. Few specialists have explored the issue of deltaic geological heritage (geoheritage), and the relevant knowledge remains scarce and non-systematised. This paper proposes the first classification of this geoheritage. Five categories are distinguished: entire-delta geological phenomenon, delta-associated “purely” geological features, delta-associated features resulting from geology–ecosystem interactions, geological features occasional to deltas, and geoarchaeological localities in deltas. Chosen as a case example, the Don River delta in the southwestern part of Russia possesses geoheritage of these categories, except for the latter. The relevant unique geological features differ by their types and ranks. Of particular interest is the phenomenon of a self-cleaning environment which prevents mercury concentration in the soil despite pollution from natural and anthropogenic sources. The complexity of the deltaic geoheritage, its co-existence with the rich biodiversity, and the aesthetical issues make geopark creation in river deltas a sensible venture. Relevant proposals have been made for Malaysia and the Netherlands–Belgium border, and the Don River delta in Russia also presents an appropriate location for geopark creation.

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Biodiversity breakpoints along stress gradients in estuaries and associated shifts in ecosystem interactions

Scientific Reports ◽

10.1038/s41598-019-54192-0 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Emily J. Douglas ◽

Andrew M. Lohrer ◽

Conrad A. Pilditch

Keyword(s):

Nitrogen Cycling ◽

Environmental Gradients ◽

Interaction Network ◽

Coastal Sediments ◽

Ecosystem Functions ◽

Ecological Interactions ◽

Fine Sediments ◽

Microbial Nitrogen ◽

Ecosystem Interactions ◽

Biodiversity Effects

AbstractDenitrification in coastal sediments can provide resilience to eutrophication in estuarine ecosystems, but this key ecosystem function is impacted directly and indirectly by increasing stressors. The erosion and loading of fine sediments from land, resulting in sedimentation and elevated sediment muddiness, presents a significant threat to coastal ecosystems worldwide. Impacts on biodiversity with increasing sediment mud content are relatively well understood, but corresponding impacts on denitrification are uncharacterised. Soft sediment ecosystems have a network of interrelated biotic and abiotic ecosystem components that contribute to microbial nitrogen cycling, but these components (especially biodiversity measures) and their relationships with ecosystem functions are sensitive to stress. With a large dataset spanning broad environmental gradients this study uses interaction network analysis to present a mechanistic view of the ecological interactions that contribute to microbial nitrogen cycling, showing significant changes above and below a stressor (mud) threshold. Our models demonstrate that positive biodiversity effects become more critical with a higher level of sedimentation stress, and show that effective ecosystem management for resilience requires different action under different scenarios.

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Themes and future directions in herbivore‐ecosystem interactions and conservation

Large Herbivore Ecology, Ecosystem Dynamics and Conservation ◽

10.1017/cbo9780511617461.018 ◽

2010 ◽

pp. 468-478

Author(s):

Pastor John ◽

Danell Kjell ◽

Bergström Roger ◽

Duncan Patrick

Keyword(s):

Future Directions ◽

Ecosystem Interactions

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Assessing the Extent of Historical, Current, and Future Land Use Systems in Uganda

Land ◽

10.3390/land7040132 ◽

2018 ◽

Vol 7 (4) ◽

pp. 132 ◽

Cited By ~ 2

Author(s):

Majaliwa Mwanjalolo ◽

Barasa Bernard ◽

Mukwaya Paul ◽

Wanyama Joshua ◽

Kutegeka Sophie ◽

...

Keyword(s):

Land Use ◽

Agricultural Land ◽

Markov Chain Model ◽

Open Water ◽

Sustainable Land Use ◽

Chain Model ◽

Land Use Systems ◽

Systems Planning ◽

Future Prediction ◽

Ecosystem Interactions

Sustainable land use systems planning and management requires a wider understanding of the spatial extent and detailed human-ecosystem interactions astride any landscape. This study assessed the extent of historical, current, and future land use systems in Uganda. The specific objectives were to (i) characterize and assess the extent of historical and current land use systems, and (ii) project future lan use systems. The land use systems were defined and classified using spatially explicit land use/cover layers for the years 1990 and 2015, while the future prediction (for the year 2040) was determined using land use systems datasets for both years through a Markov chain model. This study reveals a total of 29 classes of land use systems that can be broadly categorized as follows: three of the land use systems are agricultural, five are under bushland, four under forest, five under grasslands, two under impediments, three under wetlands, five under woodland, one under open water and urban settlement respectively. The highest gains in the land amongst the land use systems were experienced in subsistence agricultural land and grasslands protected, while the highest losses were seen in grasslands unprotected and woodland/forest with low livestock densities. By 2040, subsistence agricultural land is likely to increase by about 1% while tropical high forest with livestock activities is expected to decrease by 0.2%, and woodland/forest unprotected by 0.07%. High demand for agricultural and settlement land are mainly responsible for land use systems patchiness. This study envisages more land degradation and disasters such as landslides, floods, droughts, and so forth to occur in the country, causing more deaths and loss of property, if the rate at which land use systems are expanding is not closely monitored and regulated in the near future.

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