Fungi have been an important source for producing a wide range of secondary metabolites of widely differing chemical structures, as well as biological activities. Many of their metabolites now play a major role in pharmaceutical and agricultural industries. A number of fungi were isolated from soil and leaf litter collected from Arthur’s Pass, West Coast and Kaituna Valley using a particle filtration technique. Fungi were selected based on their unusual morphology or observed cytotoxicity and antimicrobial activity for large scale culture and extraction. A pale yellow compound was isolated from cytotoxic extracts from the culture of Aspergillus versicolor. This compound was identified as sterigmatocystin and the identity confirmed by UV profile and mass spectrometry. Five compounds were isolated from extracts prepared from two different species of Penicillium of which three were active against P388 cells (mycophenolic acid, cycloaspeptide A and mevastatin), one was active against dermatophytes (griseofulvin) and one was not active (3,4,6,8-tetrahydroxy-3-methyl-3,4-dihydroisocoumarin). Two compounds were isolated from extracts prepared from two different species of Phoma. A dark red compound was found to be novel and showed activity against P388 cells and Bacillus subtilis. A second compound also showing cytotoxicity was identified as the known compound phomenone. A further new compound was isolated from extracts of an identified dematiaceous fungus. This alkyl glucoside, however, was not bioactive.

No description available.

Fungi have been an important source for producing a wide range of secondary metabolites of widely differing chemical structures, as well as biological activities. Many of their metabolites now play a major role in pharmaceutical and agricultural industries. A number of fungi were isolated from soil and leaf litter collected from Arthur’s Pass, West Coast and Kaituna Valley using a particle filtration technique. Fungi were selected based on their unusual morphology or observed cytotoxicity and antimicrobial activity for large scale culture and extraction. A pale yellow compound was isolated from cytotoxic extracts from the culture of Aspergillus versicolor. This compound was identified as sterigmatocystin and the identity confirmed by UV profile and mass spectrometry. Five compounds were isolated from extracts prepared from two different species of Penicillium of which three were active against P388 cells (mycophenolic acid, cycloaspeptide A and mevastatin), one was active against dermatophytes (griseofulvin) and one was not active (3,4,6,8-tetrahydroxy-3-methyl-3,4-dihydroisocoumarin). Two compounds were isolated from extracts prepared from two different species of Phoma. A dark red compound was found to be novel and showed activity against P388 cells and Bacillus subtilis. A second compound also showing cytotoxicity was identified as the known compound phomenone. A further new compound was isolated from extracts of an identified dematiaceous fungus. This alkyl glucoside, however, was not bioactive.

This research evaluates the decomposition of leaf litter while in litter traps. More specifically this study asks, ‘Does sugar maple (Acer saccharum Marsh.), American basswood (Tilia Americana L.) and American beech (Fagus grandifolia Ehrh.) leaf litter collected bi-weekly from litter traps undergo a loss of dry mass and nutrient content (C, N, P, K, Ca and Mg) in comparison to freshly abscised leaf litter?’The objective of the initial experiment was to determine if sugar maple, basswood and beech leaf litter collecting in litter traps, while exposed to in-situ conditions, experienced decomposition. Results indicated that sugar maple, basswood and beech leaf litter experienced early stages of decomposition and identified precipitation, freezing temperatures and microbial activity as possible mechanisms for the observed decomposition. It was found that the dry weight of sugar maple and basswood differed significantly (p < 0.05 and p < 0.10, respectively) post- 14-day experiment period as compared to the initial dry weight. Consequently, three experiments were completed to examine the aforementioned variables. Conclusions were based on measured changes in the mass and nutrient (C, N, P, K, Ca and Mg) content of freshly abscised sugar maple, basswood and beech leaf litter under ex-situ conditions. It was found that the dry weight sugar maple and basswood leaf litter exposed to 30 mm, 60 mm and 100 mm of precipitation differed significantly (p < 0.05) as compared to freshly abscised leaf litter. In general, this research affirmed that precipitation and freezing temperature contribute to a change in mass and nutrient content of leaf litter collecting in litter traps. Furthermore, through measurable production of CO2 and Community Level Physiological Profiling it was determined that microbes are present and active on the leaf surface and contribute to the decomposition of leaf litter in litter traps.

This research evaluates the decomposition of leaf litter while in litter traps. More specifically this study asks, ‘Does sugar maple (Acer saccharum Marsh.), American basswood (Tilia Americana L.) and American beech (Fagus grandifolia Ehrh.) leaf litter collected bi-weekly from litter traps undergo a loss of dry mass and nutrient content (C, N, P, K, Ca and Mg) in comparison to freshly abscised leaf litter?’The objective of the initial experiment was to determine if sugar maple, basswood and beech leaf litter collecting in litter traps, while exposed to in-situ conditions, experienced decomposition. Results indicated that sugar maple, basswood and beech leaf litter experienced early stages of decomposition and identified precipitation, freezing temperatures and microbial activity as possible mechanisms for the observed decomposition. It was found that the dry weight of sugar maple and basswood differed significantly (p < 0.05 and p < 0.10, respectively) post- 14-day experiment period as compared to the initial dry weight. Consequently, three experiments were completed to examine the aforementioned variables. Conclusions were based on measured changes in the mass and nutrient (C, N, P, K, Ca and Mg) content of freshly abscised sugar maple, basswood and beech leaf litter under ex-situ conditions. It was found that the dry weight sugar maple and basswood leaf litter exposed to 30 mm, 60 mm and 100 mm of precipitation differed significantly (p < 0.05) as compared to freshly abscised leaf litter. In general, this research affirmed that precipitation and freezing temperature contribute to a change in mass and nutrient content of leaf litter collecting in litter traps. Furthermore, through measurable production of CO2 and Community Level Physiological Profiling it was determined that microbes are present and active on the leaf surface and contribute to the decomposition of leaf litter in litter traps.

Headwaters, which are the most common stream order in the landscape, are mostly dependent on energy produced in the terrestrial system, largely consisting of leaf litter from riparian vegetation. The aim of this study was to investigate the decomposition in headwaters of leaf litter from three native (alder, birch, spruce) and one non-native (lodgepole pine) species and how decomposition responds to changes in the environment. Further, microbial and shredder influences on leaf-litter decomposition and aquatic decomposer ability to adapt to non-native species was investigated. By using field-data from this study, calculations were made to assess if microbes and shredders are resource limited. Litterbags were placed in 20 headwater streams in northern Sweden that varied in water chemistry, stream physical characteristics and riparian vegetation. The results revealed that species litter decomposition of different plant species was affected differently by changes in environmental variables. Alder and birch decomposition were positively associated, whereas lodgepole pine deviated from the other species in decomposition and its relationship with important environmental variables, indicating that the ability of the boreal aquatic systems to decompose litter differs between introduced and native species. When including macroinvertebrates, shredder fragmentation generally increased decomposition, but was not significant for all sites. Resource availability for microbes and shredders was controlled by litter input, and no risk of resource limitations was evident during the study period. These findings highlight a complexity of the decomposition process that needs to be considered when predicting changes due to human activities.

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Large stands of Arundinaria gigantea (Walt.) Muhl., called canebrakes, were vital to wildlife and lowland ecosystem functions and historically covered millions of acres in the southeastern United States. Since European settlement, human disturbance (i.e, clearing for agriculture and fire suppression) has caused giant canebrakes to become critically endangered ecosystems. Increasing evidence suggests the loss of canebrakes has directly impacted riparian ecosystems, resulting in increased soil erosion, poorer water quality, and reduced flood control. Cane's ecological importance has led to an increased interest in canebrake restoration in riparian zones. To examine the role that cane plays in nutrient cycling and to attempt to determine targeted restoration sites, a four phase research strategy was designed to determine physical and chemical properties of existing riparian stands of native giant cane and their associated soils. Phase one was a GIS analysis to determine what geographical features may be used in selecting sites within a landscape suitable for canebrake restoration. First, common physical site characteristics for 140 existing southern Illinois canebrakes were determined. Soil taxonomy and pH were used to represent soil characteristics and percent slope was used as a topographic metric. These factors, combined with digital elevation models and land cover in GIS were used to identify the potential suitability of sites within the watershed for canebrake plantings and general riparian restoration. The following soil characteristics were determined to be associated with giant cane success: percentage of area containing slopes of 3 percent or less, fine to coarse-silty textures, pH of 5.3 - 6.7, effective cation exchange capacity of less than 30 units, available water holding capacity greater than 0.12, bulk density of 1.37 - 1.65 g cm-3, and percent clay of 11 - 55. Eighty-percent of existing giant cane sites were found within these slope and soil characteristics. The total area of potential riparian canebrake landscapes based on these parameters is 13,970 hectares (35,600 acres) within the Cache River watershed. The remaining three phases examined the role that cane plays in nutrient cycling. Phase two determined the pools and cycling of nitrogen and carbon in canebrakes and compared those to nearby agricultural and forested riparian areas. Phase three quantified the N2O and CO2 fluxes from canebrakes and adjacent forested areas. Phase four included methods to quantify nutrient content of leaf litter and live leaves from existing canebrakes to estimate the nutrient use efficiency of cane. Further, a decomposition study was conducted to calculate the decomposition rate of cane leaves and to explore the litter quality attributes of giant cane. The primary purpose of phase two was to compare the effects of perennial riparian vegetation (giant cane and forest) and annual crops on soil quality, nitrogen cycling, and physical properties. This was to determine if any of them have a significant influence on giant cane distribution, while focusing on nitrogen dynamics to help determine why giant cane is a successful riparian buffer species. Five study sites in the Cache River watershed that had cane, agricultural fields (corn-soybean rotation), and forested areas adjacent to one another were selected. Data were collected on soil texture, carbon/nitrogen ratios, bulk density, nitrogen content (as ammonia and nitrate), and net nitrogen mineralization rates. The crop sites had significantly lower soil C:N ratios than both forest and cane (9.8:1 vs. 10.9:1 and 10.7:1, respectively), though all sites had ratios less than 25:1, indicating a tendency toward nitrogen mineralization. Forest soils had significantly higher rates of net mineralization than cane (19.0 μg m-2 day-1 and 6.6 μg m-2 day-1, respectively), with crop not significantly different from either cane or forest (8.0 μg m-2 day-1). Cane had higher levels of soil carbon and nitrogen when compared to forest and crop soils. Cane can be successful in wetter areas than previously thought, implying that the range of conditions that will support cane is broader than previously thought. Overall, there were few identifiable soil controls on giant cane distribution, or those that differentiate long-standing canebrakes from the nearby crop and forest land. For Phase three, nitrous oxide and carbon dioxide emissions were measured monthly for one year in riparian canebrakes and forests in southern Illinois to determine the rates of greenhouse gas (GHG) fluxes in bottomland riparian areas. Carbon dioxide emissions had a strong correlation with soil temperature (p < 0.001, r2= 0.54), but not with soil water content (p > 0.05), and were greater during the warmer months. Nitrous oxide emissions had a correlation with soil water content (p=0.470, r2 = 0.11), but no relation with soil temperature (p > 0.05), nor a difference across time. Vegetation type did not appear to influence GHG fluxes. Riparian CO2 and N2O emission rates were higher than documented cropland emissions, indicating riparian restoration projects to reduce NO3 delivery to streams may affect N2O and CO2 emissions resulting in an ecosystem tradeoff between water quality and air quality. Leaf deposition, N resorption efficiency and proficiency, and decomposition rates were analyzed in riparian stands of Arundinaria gigantea in southern Illinois for the first time in Phase four. Leaf litter was collected from five established canebrakes monthly over one year and a decomposition study was conducted over 72 weeks. Live leaves, freshly senesced leaves, and decomposed leaves were analyzed for carbon and nitrogen content. Leaf litterfall biomass peaked in November at twice the monthly average for all but one site, indicating a resemblance to deciduous leaf fall patterns. Nitrogen and carbon levels decreased 48% and 30%, respectively, between live leaves and 72 weeks decomposed. High soil moisture appeared to slow decomposition rates, perhaps due to the creation of anaerobic conditions. Cane leaves have low resorption proficiency and nutrient use proficiency, suggesting that these riparian canebrakes are not nitrogen limited. These results will help improve our understanding of the role that giant cane plays in a riparian ecosystem and help focus cane restoration efforts in southern Illinois.

In north Mississippi, I evaluated fuel loads in the late dormant season and after leaf fall in unburned areas and after a dormant season burn. Fuel loads beneath winged elm (Ulmus alata) were assessed to determine if this shade-tolerant species impacts fine fuel loads in the area immediately near its bole. I found leaf litter fuel loads are higher after leaf fall suggesting that burns conducted closer to leaf fall may have increased burn intensity. Burning reduced leaf litter fuels and exposed mineral soil which returned to pre-burn levels following leaf fall. Declines in duff layer fuels were not evident until after leaf fall. Leaf litter fuels underneath winged elms had higher mass and percentage of winged elm litter beneath them compared to areas away from them. These results will help determine appropriate time for restoring prescribed fire and the implications of encroachment by non-oak species into upland oak forests.

No description available.