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Full-Text Articles in Life Sciences
Frayed Connections: How Long-Term Nitrogen Additions Disrupt Plant-Soil Interactions And The Carbon Cycle Of A Temperate Forest, Brooke A. Eastman
Frayed Connections: How Long-Term Nitrogen Additions Disrupt Plant-Soil Interactions And The Carbon Cycle Of A Temperate Forest, Brooke A. Eastman
Graduate Theses, Dissertations, and Problem Reports
Forests are expected to mitigate some of the negative effects of climate change by sequestering anthropogenic carbon (C) from the atmosphere, but the degree to which they drawn down C will depend on the availability of key nutrients, such as nitrogen (N). There is a fair amount of uncertainty in the future of the forest C sink, mostly owing to the fate of soil organic matter (SOM) and soil heterotrophic respiration to future conditions. In N limited systems, plants allocate a significant amount of their photosynthate belowground for the acquisition of nutrients, but under conditions of chronic N deposition, plants …
Nitrogen Addition Shapes Soil Phosphorus Availability In Two Reforested Tropical Forests In Southern China, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Hua Fang, Feifei Zhu, Yunting Fang, Wei Zhang, Juan Huang
Nitrogen Addition Shapes Soil Phosphorus Availability In Two Reforested Tropical Forests In Southern China, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Hua Fang, Feifei Zhu, Yunting Fang, Wei Zhang, Juan Huang
Frank S. Gilliam
Scant information is available on how soil phosphorus (P) availability responds to atmospheric nitrogen (N) deposition, especially in the tropical zones. This study examined the effect of N addition on soil P availability, and compared this effect between forest sites of contrasting land-use history. Effects of N addition on soil properties, litterfall production, P release from decomposing litter, and soil P availability were studied in a disturbed (reforested pine forest with previous understory vegetation and litter harvesting) and a rehabilitated (reforested mixed pine/broadleaf forest with no understory vegetation and litter harvesting) tropical forest in southern China. Experimental N-treatments (above ambient) …
Estimated Losses Of Plant Biodiversity Across The U.S. From Historical N Deposition From 1985—2010., Christopher M. Clark, Philip E. Morefield, Frank S. Gilliam, Linda H. Pardo
Estimated Losses Of Plant Biodiversity Across The U.S. From Historical N Deposition From 1985—2010., Christopher M. Clark, Philip E. Morefield, Frank S. Gilliam, Linda H. Pardo
Frank S. Gilliam
Although nitrogen (N) deposition is a significant threat to herbaceous plant biodiversity worldwide, it is not a new stressor for many developed regions. Only recently has it become possible to estimate historical impacts nationally for the United States. We used 26 years (1985–2010) of deposition data, with ecosystem-specific functional responses from local field experiments and a national critical loads (CL) database, to generate scenario-based estimates of herbaceous species loss. Here we show that, in scenarios using the low end of the CL range, N deposition exceeded critical loads over 0.38, 6.5, 13.1, 88.6, and 222.1 million ha for the Mediterranean …
Effects Of Excess Nitrogen Deposition On Rubus Spp. (Raspberry) Within A Central Appalachian Hardwood Forest, Jake H. Billmyer
Effects Of Excess Nitrogen Deposition On Rubus Spp. (Raspberry) Within A Central Appalachian Hardwood Forest, Jake H. Billmyer
Theses, Dissertations and Capstones
This thesis contributes to on-going research at Marshall University on effects of excess nitrogen (N) deposition on hardwood forests. Excess N can decrease plant biodiversity and enhance loss of nutrients (e.g., Ca++). Preliminary results have suggested that excess N has increased cover of Rubus (blackberry) in the herbaceous layer. The purpose of this study was to quantify the response of Rubus to the N treatment, relating Rubus cover to species richness and using foliar analysis to examine effects on nutrient availability. It is expected that increased Rubus will decrease biodiversity by eliminating N-efficient species, and that added N …
Nitrogen Deposition Contributes To Soil Acidification In Tropical Ecosystems, Xiankai Lu, Qinggong Mao, Frank S. Gilliam, Yiqi Luo, Jiangming Mo
Nitrogen Deposition Contributes To Soil Acidification In Tropical Ecosystems, Xiankai Lu, Qinggong Mao, Frank S. Gilliam, Yiqi Luo, Jiangming Mo
Biological Sciences Faculty Research
Elevated anthropogenic nitrogen (N) deposition has greatly altered terrestrial ecosystem functioning, threatening ecosystem health via acidification and eutrophication in temperate and boreal forests across the northern hemisphere. However, response of forest soil acidification to N deposition has been less studied in humid tropics compared to other forest types. This study was designed to explore impacts of long-term N deposition on soil acidification processes in tropical forests. We have established a long-term N deposition experiment in an N-rich lowland tropical forest of Southern China since 2002 with N addition as NH4NO3 of 0, 50, 100 and 150 kg …
Estimated Losses Of Plant Biodiversity Across The U.S. From Historical N Deposition From 1985—2010., Christopher M. Clark, Philip E. Morefield, Frank S. Gilliam, Linda H. Pardo
Estimated Losses Of Plant Biodiversity Across The U.S. From Historical N Deposition From 1985—2010., Christopher M. Clark, Philip E. Morefield, Frank S. Gilliam, Linda H. Pardo
Biological Sciences Faculty Research
Although nitrogen (N) deposition is a significant threat to herbaceous plant biodiversity worldwide, it is not a new stressor for many developed regions. Only recently has it become possible to estimate historical impacts nationally for the United States. We used 26 years (1985–2010) of deposition data, with ecosystem-specific functional responses from local field experiments and a national critical loads (CL) database, to generate scenario-based estimates of herbaceous species loss. Here we show that, in scenarios using the low end of the CL range, N deposition exceeded critical loads over 0.38, 6.5, 13.1, 88.6, and 222.1 million ha for the Mediterranean …
Effects Of Atmospheric Nitrogen Deposition On The Herbaceous Layer Of A Central Appalachian Hardwood Forest, Frank S. Gilliam, Anne W. Hockenberry, Mary Beth Adams
Effects Of Atmospheric Nitrogen Deposition On The Herbaceous Layer Of A Central Appalachian Hardwood Forest, Frank S. Gilliam, Anne W. Hockenberry, Mary Beth Adams
Frank S. Gilliam
Additions of nitrogen (N) have been shown to alter species diversity of plant communities, with most experimental studies having been carried out in communities dominated by herbaceous species. We examined seasonal and inter-annual patterns of change in the herbaceous layer of two watersheds of a central Appalachian hardwood forest that differed in experimental treatment. This study was carried out at the Fernow Experimental Forest, West Virginia, using two adjacent watersheds: WS4 (mature, second-growth hardwood stand, untreated reference), and WS3. Seven circular 0.04-ha sample plots were established in eachwatershed to represent its full range of elevation and slope aspect. The herbaceous …
Effects Of Experimental Nitrogen Additions On Plant Diversity In Tropical Forests Of Contrasting Disturbance Regimes In Southern China, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Guirui Yu, Wei Zhang, Yunting Fang, Juan Huang
Effects Of Experimental Nitrogen Additions On Plant Diversity In Tropical Forests Of Contrasting Disturbance Regimes In Southern China, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Guirui Yu, Wei Zhang, Yunting Fang, Juan Huang
Frank S. Gilliam
Responses of understory plant diversity to nitrogen (N) additions were investigated in reforested forests of contrasting disturbance regimes in southern China from 2003 to 2008: disturbed forest (withharvesting of understory vegetation and litter) and rehabilitated forest (without harvesting). Experimental additions of N were administered as the following treatments: Control, 50 kg N ha1yr1, and 100kg N ha1yr1. Nitrogen additions did not significantly affect understory plant richness, density,and cover in the disturbed forest. Similarly, no significant response was found for canopy closure in thisforest. In the rehabilitated forest, species richness and density showed no significant response to Nadditions; however, understory cover …
Effects Of Experimental Nitrogen Additions On Plant Diversity In Tropical Forests Of Contrasting Disturbance Regimes In Southern China, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Guirui Yu, Wei Zhang, Yunting Fang, Juan Huang
Effects Of Experimental Nitrogen Additions On Plant Diversity In Tropical Forests Of Contrasting Disturbance Regimes In Southern China, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Guirui Yu, Wei Zhang, Yunting Fang, Juan Huang
Biological Sciences Faculty Research
Responses of understory plant diversity to nitrogen (N) additions were investigated in reforested forests of contrasting disturbance regimes in southern China from 2003 to 2008: disturbed forest (withharvesting of understory vegetation and litter) and rehabilitated forest (without harvesting). Experimental additions of N were administered as the following treatments: Control, 50 kg N ha1yr1, and 100kg N ha1yr1. Nitrogen additions did not significantly affect understory plant richness, density,and cover in the disturbed forest. Similarly, no significant response was found for canopy closure in thisforest. In the rehabilitated forest, species richness and density showed no significant response to Nadditions; however, understory cover …
Nitrogen Addition Shapes Soil Phosphorus Availability In Two Reforested Tropical Forests In Southern China, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Hua Fang, Feifei Zhu, Yunting Fang, Wei Zhang, Juan Huang
Nitrogen Addition Shapes Soil Phosphorus Availability In Two Reforested Tropical Forests In Southern China, Xiankai Lu, Jiangming Mo, Frank S. Gilliam, Hua Fang, Feifei Zhu, Yunting Fang, Wei Zhang, Juan Huang
Biological Sciences Faculty Research
Scant information is available on how soil phosphorus (P) availability responds to atmospheric nitrogen (N) deposition, especially in the tropical zones. This study examined the effect of N addition on soil P availability, and compared this effect between forest sites of contrasting land-use history. Effects of N addition on soil properties, litterfall production, P release from decomposing litter, and soil P availability were studied in a disturbed (reforested pine forest with previous understory vegetation and litter harvesting) and a rehabilitated (reforested mixed pine/broadleaf forest with no understory vegetation and litter harvesting) tropical forest in southern China. Experimental N-treatments (above ambient) …
Effects Of Atmospheric Nitrogen Deposition On The Herbaceous Layer Of A Central Appalachian Hardwood Forest, Frank S. Gilliam, Anne W. Hockenberry, Mary Beth Adams
Effects Of Atmospheric Nitrogen Deposition On The Herbaceous Layer Of A Central Appalachian Hardwood Forest, Frank S. Gilliam, Anne W. Hockenberry, Mary Beth Adams
Biological Sciences Faculty Research
Additions of nitrogen (N) have been shown to alter species diversity of plant communities, with most experimental studies having been carried out in communities dominated by herbaceous species. We examined seasonal and inter-annual patterns of change in the herbaceous layer of two watersheds of a central Appalachian hardwood forest that differed in experimental treatment. This study was carried out at the Fernow Experimental Forest, West Virginia, using two adjacent watersheds: WS4 (mature, second-growth hardwood stand, untreated reference), and WS3. Seven circular 0.04-ha sample plots were established in eachwatershed to represent its full range of elevation and slope aspect. The herbaceous …
Effects Of Excessive Nitrogen Deposition On Foliar Nutrient Dynamics, Nutrient Concentrations, And Nutrient Ratios In A Central Appalachian Hardwood Forest, Sarah Beth Burdette
Effects Of Excessive Nitrogen Deposition On Foliar Nutrient Dynamics, Nutrient Concentrations, And Nutrient Ratios In A Central Appalachian Hardwood Forest, Sarah Beth Burdette
Theses, Dissertations and Capstones
Many forested systems of the eastern US are becoming significantly nitrogen (N) saturated due to chronic N deposition from the atmosphere. Nitrogen saturation has the potential to alter important internal plant processes, such as nutrient cycling. While extensive research has been conducted on the responses of soil to N saturation, considerably less research has focused on the response of plant nutrient dynamics, nutrient concentrations, and nutrient ratios to excess N. Research was conducted on two watersheds at the Fernow Experimental Forest in West Virginia: WS3 (fertilized with ammonium sulfate annually since 1989) and WS7 (untreated control). Presenescent and senesced leaves …