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Articles 1 - 30 of 57
Full-Text Articles in Forest Sciences
Decadal Effects Of Thinning On Understory Light Environments And Plant Community Structure In A Subtropical Forest, Ho-Chen Tsai, Jyh-Min Chiang, Ryan Mcewan, Teng-Chiu Lin
Decadal Effects Of Thinning On Understory Light Environments And Plant Community Structure In A Subtropical Forest, Ho-Chen Tsai, Jyh-Min Chiang, Ryan Mcewan, Teng-Chiu Lin
Ryan McEwan
Canopy-opening disturbance such as thinning has immediate and substantive effects on understory microclimate and therefore the establishment and growth of understory plants. A large number of studies have reported the effects of thinning on tree growth, but few studies have examined long-term effects of thinning on understory light environments and species and functional diversity of understory plants. Even less is known whether the change in understory plant community structure observed following canopy disturbance is short-lived and would diminish as the canopy closes or a long lasting due to legacy effects. We examined the effects of an experimental removal of 25% …
The Role Of Environmental Filtering In Structuring Appalachian Tree Communities: Topographic Influences On Functional Diversity Are Mediated Through Soil Characteristics, Julia I. Chapman, Ryan W. Mcewan
The Role Of Environmental Filtering In Structuring Appalachian Tree Communities: Topographic Influences On Functional Diversity Are Mediated Through Soil Characteristics, Julia I. Chapman, Ryan W. Mcewan
Ryan McEwan
Identifying the drivers of community assembly has long been a central goal in ecology, and the development of functional diversity indices has provided a new way of detecting the influence of environmental gradients on biotic communities. For an old-growth Appalachian forest, we used path analysis to understand how patterns of tree functional diversity relate to topography and soil gradients and to determine whether topographic effects are mediated through soil chemistry. All of our path models supported the idea of environmental filtering: stressful areas (high elevation, low soil moisture, low soil nutrients) were occupied by communities of low functional diversity, which …
Utilization Of Woody Browse By White-Tailed Deer (Odocoileus Virginianus) In Valley Forge National Park, Joanne T. Pomerantz, Joan M. Welch
Utilization Of Woody Browse By White-Tailed Deer (Odocoileus Virginianus) In Valley Forge National Park, Joanne T. Pomerantz, Joan M. Welch
Joan Welch
No abstract provided.
Invasive And Native Plant Response To Fire In A Pennsylvania Piedmont Woodland, Joan M. Welch
Invasive And Native Plant Response To Fire In A Pennsylvania Piedmont Woodland, Joan M. Welch
Joan Welch
No abstract provided.
Analisis De La Fragmentacion De Los Espacios Naturales En El Sector Sur Del Area Urbana De Girona, Josep Pinta, Josep Vila, Joan M. Welch
Analisis De La Fragmentacion De Los Espacios Naturales En El Sector Sur Del Area Urbana De Girona, Josep Pinta, Josep Vila, Joan M. Welch
Joan Welch
No abstract provided.
Deer Browse In The Interior Forest Of Warwick County Park, Jacquelyn Arnold, Joan M. Welch
Deer Browse In The Interior Forest Of Warwick County Park, Jacquelyn Arnold, Joan M. Welch
Joan Welch
No abstract provided.
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) …
Interspecific Divergence In Foliar Nutrient Dynamics And Stem Growth In A Temperate Forest In Response To Chronic Nitrogen Inputs, Jeffrey D. May, Sarah Beth Burdette, Frank S. Gilliam, Mary Beth Adams
Interspecific Divergence In Foliar Nutrient Dynamics And Stem Growth In A Temperate Forest In Response To Chronic Nitrogen Inputs, Jeffrey D. May, Sarah Beth Burdette, Frank S. Gilliam, Mary Beth Adams
Jeffrey May
We studied the effects of excessive nitrogen (N) fertilization on foliar nutrient dynamics and stem growth in three important tree species in a mixed-deciduous forest. Stem diameter growth, foliar N concentrations, nitrogen–phosphorus (N/P) ratios, and nutrient resorption were determined for Acer rubrum L. (ACRU), Liriodendron tulipifera L. (LITU), and Prunus serotina Ehrh. (PRSE) on two 30-year-old watersheds at the Fernow Experimental Forest, West Virginia, USA: WS3, fertilized annually with 35 kg ammonium sulfate·ha-1 since 1989, and WS7, an untreated control watershed. In an earlier (1992) study, foliar N concentrations of all three species averaged 11% higher in WS3 than …
Interspecific Divergence In Foliar Nutrient Dynamics And Stem Growth In A Temperate Forest In Response To Chronic Nitrogen Inputs, Jeffrey D. May, Sarah Beth Burdette, Frank S. Gilliam, Mary Beth Adams
Interspecific Divergence In Foliar Nutrient Dynamics And Stem Growth In A Temperate Forest In Response To Chronic Nitrogen Inputs, Jeffrey D. May, Sarah Beth Burdette, Frank S. Gilliam, Mary Beth Adams
Jeffrey May
We studied the effects of excessive nitrogen (N) fertilization on foliar nutrient dynamics and stem growth in three important tree species in a mixed-deciduous forest. Stem diameter growth, foliar N concentrations, nitrogen–phosphorus (N/P) ratios, and nutrient resorption were determined for Acer rubrum L. (ACRU), Liriodendron tulipifera L. (LITU), and Prunus serotina Ehrh. (PRSE) on two 30-year-old watersheds at the Fernow Experimental Forest, West Virginia, USA: WS3, fertilized annually with 35 kg ammonium sulfate ha–1 since 1989, and WS7, an untreated control watershed. In an earlier (1992) study, foliar N concentrations of all three species averaged 11% higher in WS3 than …
Interspecific Divergence In Foliar Nutrient Dynamics And Stem Growth In A Temperate Forest In Response To Chronic Nitrogen Inputs, Jeffrey D. May, Sarah Beth Burdette, Frank S. Gilliam, Mary Beth Adams
Interspecific Divergence In Foliar Nutrient Dynamics And Stem Growth In A Temperate Forest In Response To Chronic Nitrogen Inputs, Jeffrey D. May, Sarah Beth Burdette, Frank S. Gilliam, Mary Beth Adams
Frank S. Gilliam
We studied the effects of excessive nitrogen (N) fertilization on foliar nutrient dynamics and stem growth in three important tree species in a mixed-deciduous forest. Stem diameter growth, foliar N concentrations, nitrogen–phosphorus (N/P) ratios, and nutrient resorption were determined for Acer rubrum L. (ACRU), Liriodendron tulipifera L. (LITU), and Prunus serotina Ehrh. (PRSE) on two 30-year-old watersheds at the Fernow Experimental Forest, West Virginia, USA: WS3, fertilized annually with 35 kg ammonium sulfate·ha-1 since 1989, and WS7, an untreated control watershed. In an earlier (1992) study, foliar N concentrations of all three species averaged 11% higher in WS3 than …
Long-Term Nitrogen Addition Decreases Carbon Leaching In A Nitrogen-Rich Forest Ecosystem, X. Lu, Frank S. Gilliam, G. Yu, H. Chen, J. Mo
Long-Term Nitrogen Addition Decreases Carbon Leaching In A Nitrogen-Rich Forest Ecosystem, X. Lu, Frank S. Gilliam, G. Yu, H. Chen, J. Mo
Frank S. Gilliam
Dissolved organic carbon (DOC) plays a critical role in the carbon (C) cycle of forest soils, and has been recently connected with global increases in nitrogen (N) deposition. Most studies on effects of elevated N deposition on DOC have been carried out in N-limited temperate regions, with far fewer data available from N-rich ecosystems, especially in the context of chronically elevated N deposition. Furthermore, mechanisms for excess N-induced changes of DOC dynamics have been suggested to be different between the two kinds of ecosystems, because of the different ecosystem N status. The purpose of this study was to experimentally examine …
Interactive Effects Of Nitrogen And Phosphorus On Soil Microbial Communities In A Tropical Forest, Lei Liu, Tao Zhang, Frank S. Gilliam, Per Gundersen, Wei Zhang, Hao Chen, Jiangming Mo
Interactive Effects Of Nitrogen And Phosphorus On Soil Microbial Communities In A Tropical Forest, Lei Liu, Tao Zhang, Frank S. Gilliam, Per Gundersen, Wei Zhang, Hao Chen, Jiangming Mo
Frank S. Gilliam
Elevated nitrogen (N) deposition in humid tropical regions may exacerbate phosphorus (P) deficiency in forests on highly weathered soils. However, it is not clear how P availability affects soil microbes and soil carbon (C), or how P processes interact with N deposition in tropical forests. We examined the effects of N and P additions on soil microbes and soil C pools in a N-saturated old-growth tropical forest in southern China to test the hypotheses that (1) N and P addition will have opposing effects on soil microbial biomass and activity, (2) N and P addition will alter the composition of …
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 …
Variation In Vegetation And Microbial Linkages With Slope Aspect In A Montane Temperate Hardwood Forest, Frank S. Gilliam, Radim Hedl, Marketa Chudomelova, Rebecca L. Mcculley, Jim Nelson
Variation In Vegetation And Microbial Linkages With Slope Aspect In A Montane Temperate Hardwood Forest, Frank S. Gilliam, Radim Hedl, Marketa Chudomelova, Rebecca L. Mcculley, Jim Nelson
Frank S. Gilliam
Plant ecologists have long been interested in aspect-related contrasts of montane forests. Few studies have assessed correlation (linkage) among vegetation strata; fewer have included soil microbial communities. This study assessed contrasts in overstory, spring herbaceous, and soil microbial communities between northeast (NE) - and southwest (SW) -facing slopes in a second-growth West Virginia hardwood forest. We addressed three questions: (1) how do soil microbial, herbaceous layer, and overstory communities vary with slope aspect? (2) do forest vegetation strata and soil microbial communities exhibit linkage? (3) do biotic relationships and linkage vary with slope aspect? Moisture, organic matter, pH, soil NO3-, …
In Situ Nitrogen Mineralization, Nitrification, And Ammonia Volatilization In Maize Field Fertilized With Urea In Huanghuaihai Region Of Northern China, Xuelin Zhang, Qun Wang, Jun Xu, Frank S. Gilliam, Nicolas Tremblay, Chaohai Li
In Situ Nitrogen Mineralization, Nitrification, And Ammonia Volatilization In Maize Field Fertilized With Urea In Huanghuaihai Region Of Northern China, Xuelin Zhang, Qun Wang, Jun Xu, Frank S. Gilliam, Nicolas Tremblay, Chaohai Li
Frank S. Gilliam
Nitrogen (N) fertilization potentially affects soil N mineralization and leaching, and can enhance NH3 volatilization, thus impacting crop production. A fertilizer experiment with five levels of N addition (0, 79, 147, 215 and 375 kg N ha-1) was performed in 2009 and 2010 in a maize field in Huanghuaihai region, China, where > 300 kg N ha-1 has been routinely applied to soil during maize growth period of 120 days. Responses of net N mineralization, inorganic N flux (0–10cm), NH3 volatilization, and maize yield to N fertilization were measured. During the growth period, net N mineralization and nitrification varied seasonally, with …
Spatial Variation In Carbon And Nitrogen In Cultivated Soils In Henan Province, China: Potential Effect On Crop Yield, Xuelin Zhang, Qun Wang, Frank S. Gilliam, Yilun Wang, Feina Cha, Chaohai Li
Spatial Variation In Carbon And Nitrogen In Cultivated Soils In Henan Province, China: Potential Effect On Crop Yield, Xuelin Zhang, Qun Wang, Frank S. Gilliam, Yilun Wang, Feina Cha, Chaohai Li
Frank S. Gilliam
Improved management of soil carbon (C) and nitrogen (N) storage in agro-ecosystems represents an important strategy for ensuring food security and sustainable agricultural development in China. Accurate estimates of the distribution of soil C and N stores and their relationship to crop yield are crucial to developing appropriate cropland management policies. The current study examined the spatial variation of soil organic C (SOC), total soil N (TSN), and associated variables in the surface layer (0–40 cm) of soils from intensive agricultural systems in 19 counties within Henan Province, China, and compared these patterns with crop yield. Mean soil C and …
Nutrient Limitation In Three Lowland Tropical Forests In Southern China Receiving High Nitrogen Deposition: Insights From Fine Root Responses To Nutrient Additions, Feifei Zhu, Muneoki Yoh, Frank S. Gilliam, Xiankai Lu, Jiangming Mo
Nutrient Limitation In Three Lowland Tropical Forests In Southern China Receiving High Nitrogen Deposition: Insights From Fine Root Responses To Nutrient Additions, Feifei Zhu, Muneoki Yoh, Frank S. Gilliam, Xiankai Lu, Jiangming Mo
Frank S. Gilliam
Elevated nitrogen (N) deposition to tropical forests may accelerate ecosystem phosphorus (P) limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA) of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the two younger forests from long-term N accumulation. From February 2007 to July 2012, four experimental treatments were established at the following levels: Control, N-addition (150 kg N ha–1 yr–1), P-addition (150 kg P ha–1 yr–1) and N+P-addition (150 kg N …
Spatial Variation In Carbon And Nitrogen In Cultivated Soils In Henan Province, China: Potential Effect On Crop Yield, Xuelin Zhang, Qun Wang, Frank S. Gilliam, Yilun Wang, Feina Cha, Chaohai Li
Spatial Variation In Carbon And Nitrogen In Cultivated Soils In Henan Province, China: Potential Effect On Crop Yield, Xuelin Zhang, Qun Wang, Frank S. Gilliam, Yilun Wang, Feina Cha, Chaohai Li
Frank S. Gilliam
Improved management of soil carbon (C) and nitrogen (N) storage in agro-ecosystems represents an important strategy for ensuring food security and sustainable agricultural development in China. Accurate estimates of the distribution of soil C and N stores and their relationship to crop yield are crucial to developing appropriate cropland management policies. The current study examined the spatial variation of soil organic C (SOC), total soil N (TSN), and associated variables in the surface layer (0–40 cm) of soils from intensive agricultural systems in 19 counties within Henan Province, China, and compared these patterns with crop yield. Mean soil C and …
Nutrient Limitation In Three Lowland Tropical Forests In Southern China Receiving High Nitrogen Deposition: Insights From Fine Root Responses To Nutrient Additions, Feifei Zhu, Muneoki Yoh, Frank S. Gilliam, Xiankai Lu, Jiangming Mo
Nutrient Limitation In Three Lowland Tropical Forests In Southern China Receiving High Nitrogen Deposition: Insights From Fine Root Responses To Nutrient Additions, Feifei Zhu, Muneoki Yoh, Frank S. Gilliam, Xiankai Lu, Jiangming Mo
Frank S. Gilliam
Elevated nitrogen (N) deposition to tropical forests may accelerate ecosystem phosphorus (P) limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA) of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the two younger forests from long-term N accumulation. From February 2007 to July 2012, four experimental treatments were established at the following levels: Control, N-addition (150 kg N ha–1 yr–1), P-addition (150 kg P ha–1 yr–1) and N+P-addition (150 kg N …
In Situ Nitrogen Mineralization, Nitrification, And Ammonia Volatilization In Maize Field Fertilized With Urea In Huanghuaihai Region Of Northern China, Xuelin Zhang, Qun Wang, Jun Xu, Frank S. Gilliam, Nicolas Tremblay, Chaohai Li
In Situ Nitrogen Mineralization, Nitrification, And Ammonia Volatilization In Maize Field Fertilized With Urea In Huanghuaihai Region Of Northern China, Xuelin Zhang, Qun Wang, Jun Xu, Frank S. Gilliam, Nicolas Tremblay, Chaohai Li
Frank S. Gilliam
Nitrogen (N) fertilization potentially affects soil N mineralization and leaching, and can enhance NH3 volatilization, thus impacting crop production. A fertilizer experiment with five levels of N addition (0, 79, 147, 215 and 375 kg N ha-1) was performed in 2009 and 2010 in a maize field in Huanghuaihai region, China, where > 300 kg N ha-1 has been routinely applied to soil during maize growth period of 120 days. Responses of net N mineralization, inorganic N flux (0–10cm), NH3 volatilization, and maize yield to N fertilization were measured. During the growth period, net N mineralization and nitrification varied seasonally, with …
Environmental Forcing Does Not Induce Diel Or Synoptic Variation In The Carbon Isotope Content Of Forest Soil Respiration, Steven J. Hall, D. R. Bowling, J. E. Egan
Environmental Forcing Does Not Induce Diel Or Synoptic Variation In The Carbon Isotope Content Of Forest Soil Respiration, Steven J. Hall, D. R. Bowling, J. E. Egan
Steven J. Hall
Recent studies have examined temporal fluctuations in the amount and carbon isotope content (δ13C) of CO2 produced by the respiration of roots and soil organisms. These changes have been correlated with diel cycles of environmental forcing (e.g., sunlight and soil temperature) and with synoptic-scale atmospheric motion (e.g., rain events and pressure-induced ventilation). We used an extensive suite of measurements to examine soil respiration over 2 months in a subalpine forest in Colorado, USA (the Niwot Ridge AmeriFlux forest). Observations included automated measurements of CO2 and δ13C of CO2 in the soil efflux, the soil gas profile, and forest air. There …
Two Hundred Years Of Forest Change: Effects Of Urbanization On Tree Species Composition And Structure, Rebecca W. Dolan
Two Hundred Years Of Forest Change: Effects Of Urbanization On Tree Species Composition And Structure, Rebecca W. Dolan
Rebecca W. Dolan
Despite their importance, the dynamics of urban floras are not well understood and quantitative historical data are rare. The current study used three data sets for trees in Indianapolis/Marion County, Indiana, U.S., to document change over 200 years to the original beech-maple forest and to examine future implications of contemporary tree planting efforts in light of these changes. Data on tree composition and size collected before significant settlement in the early 1800s are compared with recent surveys of trees in remnant natural areas and with trees found on city streets and rights-of-way. All the species recorded in historical surveys are …
Annual Brome Biocontrol After Wildfire Using A Native Fungal Seed Pathogen, Susan E. Meyer, Phil S. Allen, Julie Beckstead, Michael Gregg, Heidi Newsome, Kathleen Harcksen, Gary Kidd, Glenn Paulsen, Karen Prentice, Dana Quinney, David Wilderman, Stephanie Carlson, Suzette Clement, Duane Smith, Thom Stewart, Katie Merrill, Keith Merrill, Kedra Foote, Stephen Harrison, Kelly Bergen, Brian Connelly, Trevor Davis, Sandra Dooley, Michael Huck, Laura Street, Lauren Miller
Annual Brome Biocontrol After Wildfire Using A Native Fungal Seed Pathogen, Susan E. Meyer, Phil S. Allen, Julie Beckstead, Michael Gregg, Heidi Newsome, Kathleen Harcksen, Gary Kidd, Glenn Paulsen, Karen Prentice, Dana Quinney, David Wilderman, Stephanie Carlson, Suzette Clement, Duane Smith, Thom Stewart, Katie Merrill, Keith Merrill, Kedra Foote, Stephen Harrison, Kelly Bergen, Brian Connelly, Trevor Davis, Sandra Dooley, Michael Huck, Laura Street, Lauren Miller
Benjamin L. Harwood
A major problem in post-fire restoration of semi-arid shrublands dominated by annual bromes is the presence of carryover seed banks that cannot be controlled using conventional methods. These seeds can provide significant competition for seeded species in the years following treatment. We investigated the feasibility of using a naturally occurring seed pathogen, the ascomycete Pyrenophora semeniperda, as a biocontrol organism for eliminating this carryover seed bank. We carried out the necessary technology development to create and apply field inoculum to cheatgrass- or red brome-infested areas (both burned and unburned) at six sites located in three states across two years of …
Large Fluxes And Rapid Turnover Of Mineral-Associated Carbon Across Topographic Gradients In A Humid Tropical Forest: Insights From Paired 14c Analysis, Steven J. Hall, G. Mcnicol, T. Natake, W. L. Silver
Large Fluxes And Rapid Turnover Of Mineral-Associated Carbon Across Topographic Gradients In A Humid Tropical Forest: Insights From Paired 14c Analysis, Steven J. Hall, G. Mcnicol, T. Natake, W. L. Silver
Steven J. Hall
It has been proposed that the large soil carbon (C) stocks of humid tropical forests result predominantly from C stabilization by reactive minerals, whereas oxygen (O2) limitation of decomposition has received much less attention. We examined the importance of these factors in explaining patterns of C stocks and turnover in the Luquillo Experimental Forest, Puerto Rico, using radiocarbon (14C) measurements of contemporary and archived samples. Samples from ridge, slope, and valley positions spanned three soil orders (Ultisol, Oxisol, Inceptisol) representative of humid tropical forests, and differed in texture, reactive metal content, O2 availability, and root biomass. Mineral-associated C comprised the …
Tb196: Temperature, Soil Moisture, And Streamflow At The Bear Brook Watershed In Maine (Bbwm), Ivan J. Fernandez, Joseph E. Karem, Stephen A. Norton, Lindsey E. Rustad
Tb196: Temperature, Soil Moisture, And Streamflow At The Bear Brook Watershed In Maine (Bbwm), Ivan J. Fernandez, Joseph E. Karem, Stephen A. Norton, Lindsey E. Rustad
Ivan J. Fernandez
The Bear Brook Watershed in Maine is a whole-ecosystem chemical manipulation initiated in 1987 to study the effects of acid deposition on forests and surface waters. The focus of this research was to understand the biogeochemical response of watersheds with emphasis on chemistry and hydrology. In 2001 a program was initiated to provide more detailed measurements of temperature and moisture to examine critical linkages amongst chemical, biological, and physical processes that ultimately work together to define ecosystem function. The purpose of this publication is to provide data from the initial phase of soil temperature, air temperature, and soil moisture measurements …
Tb162: Red Maple And White Pine Litter Quality: Initial Changes With Decomposition, Mairin T. Delaney, Ivan J. Fernandez, Jeffrey A. Simmons, Russel D. Briggs
Tb162: Red Maple And White Pine Litter Quality: Initial Changes With Decomposition, Mairin T. Delaney, Ivan J. Fernandez, Jeffrey A. Simmons, Russel D. Briggs
Ivan J. Fernandez
The specific objectives of this study were (a) to define the organic and inorganic composition of foliar litter from red maple (Acer rubrum L.) and white pine (Pinus strobus L.), and (b) to determine the shifts in the organic and inorganic composition of these two litter types during the initial stages of decomposition. These two species were chosen because of their prominence in the northeastern U.S. and the contrast they afforded in litter quality characteristics which have a strong influence on litter decomposition.
Collaborative Research: Interactive Effects Of Chronic N Deposition, Acidification, And Phosphorus Limitation On Coupled Element Cycling In Streams, Kevin S. Simons, Ivan J. Fernandez, Stephen A. Norton
Collaborative Research: Interactive Effects Of Chronic N Deposition, Acidification, And Phosphorus Limitation On Coupled Element Cycling In Streams, Kevin S. Simons, Ivan J. Fernandez, Stephen A. Norton
Ivan J. Fernandez
The overarching goal of this project is to understand how chronic acidification and nitrogen enrichment of watersheds influences coupled biogeochemical cycling in streams. Embedded in the project were two primary research elements: 1) examining nitrogen satuartion and the extent of coupling between nitrogen and phosphorus cycling and 2) resolving the interactions among acidification, phosphorus bioavailability and biotic demand for nitrogen and phosphorus. The research involved a series of stable isotope tracer experiments to document nitrogen uptake under ambient and elevated phosphrous conditions and examination of a suite of key microbial processes (denitrification, decomposition, microbial enzyme activity) at two whole-watershed experiment …
Monitoring Herpetofauna In A Managed Forest Landscape: Effects Of Habitat Types And Census Techniques, Travis J. Ryan, Thomas Philippi, Yale A. Leiden, Michael E. Dorcas, T. Bently Wigley, J. Whitfield Gibbons
Monitoring Herpetofauna In A Managed Forest Landscape: Effects Of Habitat Types And Census Techniques, Travis J. Ryan, Thomas Philippi, Yale A. Leiden, Michael E. Dorcas, T. Bently Wigley, J. Whitfield Gibbons
Travis J. Ryan
We surveyed the herpetofaunal (amphibian and reptile) communities inhabiting five types of habitat on a managed landscape. We conducted monthly surveys during 1997 in four replicate plots of each habitat type using several different methods of collection. Communities of the two wetland habitats (bottomland wetlands and isolated upland wetlands) were clearly dissimilar from the three terrestrial communities (recent clearcut, pine plantation, and mixed pine–hardwood forest). Among the three terrestrial habitats, the total herpetofaunal communities were dissimilar (P<0.10), although neither faunal constituent group alone (amphibians and squamate reptiles) varied significantly with regard to habitat. Three survey techniques used in the …
Differential Effects Of Canopy Trimming And Litter Deposition On Litterfall And Nutrient Dynamics In A Wet Subtropical Forest, Steven J. Hall, Whendee L. Silver, Grizelle González
Differential Effects Of Canopy Trimming And Litter Deposition On Litterfall And Nutrient Dynamics In A Wet Subtropical Forest, Steven J. Hall, Whendee L. Silver, Grizelle González
Steven J. Hall
Humid tropical forests have the highest rates of litterfall production globally, which fuels rapid nutrient recycling and high net ecosystem production. Severe storm events significantly alter patterns in litterfall mass and nutrient dynamics through a combination of canopy disturbance and litter deposition. In this study, we used a large-scale long-term manipulation experiment to explore the separate and combined effects of canopy trimming and litter deposition on litterfall rates and litter nutrient concentrations and content. The deposition of fine litter associated with the treatments was equivalent to more than two times the annual fine litterfall mass and nutrient content in control …
Breaking The Enzymatic Latch: Impacts Of Reducing Conditions On Hydrolytic Enzyme Activity In Tropical Forest Soils, Steven J. Hall, Jonathan Treffkorn, Whendee L. Silver
Breaking The Enzymatic Latch: Impacts Of Reducing Conditions On Hydrolytic Enzyme Activity In Tropical Forest Soils, Steven J. Hall, Jonathan Treffkorn, Whendee L. Silver
Steven J. Hall
The enzymatic latch hypothesis proposes that oxygen (O2) limitation promotes wetland carbon (C) storage by indirectly decreasing the activities of hydrolytic enzymes that decompose organic matter. Humid tropical forest soils are often characterized by low and fluctuating redox conditions and harbor a large pool of organic matter, yet they also have the fastest decomposition rates globally. We tested the enzymatic latch hypothesis across a soil O2 gradient in the Luquillo Experimental Forest, Puerto Rico, USA. Enzyme activities expressed on a soil mass basis did not systematically decline across a landscape O2 gradient, nor did phenolics accumulate, the proposed mechanism of …