bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Potential for Carbon Sequestration Through Reforestation of Abandoned Tropical Agricultural and Pasture Lands
Authors: Silver W. L. , Ostertag R. , Lugo A. E. 
Published: March 2003

AbstractApproximately half of the tropical biome is in some stage of recovery from past human disturbance, most of which is in secondary forests growing on abandoned agricultural lands and pastures. Reforestation of these abandoned lands, both natural and managed, has been proposed as a means to help offset increasing carbon emissions to the atmosphere. In this paper we discuss the potential of these forests to serve as sinks for atmospheric carbon dioxide in aboveground biomass and soils. A review of literature data shows that aboveground biomass increases at a rate of 6.2 Mg ha−1yr−1during the first 20 years of succession, and at a rate of 2.9 Mg ha−1yr−1over the first 80 years of regrowth. During the first 20 years of regrowth, forests in wet life zones have the fastest rate of aboveground carbon accumulation with reforestation, followed by dry and moist forests. Soil carbon accumulated at a rate of 0.41 Mg ha−1yr−1over a 100‐year period, and at faster rates during the first 20 years (1.30 Mg carbon ha−1yr−1). Past land use affects the rate of both above‐ and belowground carbon sequestration. Forests growing on abandoned agricultural land accumulate biomass faster than other past land uses, while soil carbon accumulates faster on sites that were cleared but not developed, and on pasture sites. Our results indicate that tropical reforestation has the potential to serve as a carbon offset mechanism both above‐ and belowground for at least 40 to 80 years, and possibly much longer. More research is needed to determine the potential for longer‐term carbon sequestration for mitigation of atmospheric CO2emissions.
The Need for Strategic Planning in Passive Restoration of Wildlife Populations
Authors: Scott Thomas A. , Wehtje Walter , Wehtje Morgan 
Published: March 2003

AbstractThere are two reasons for strategic planning in passive wildlife restoration: first, to maximize the potential for colonization of restoration sites in challenged landscapes, and second, to maximize the contribution of each restoration project to regional, management area, ecosystem, or target species goals. Landscape configuration and the demographic/dispersal characteristics of target species can govern the level of wildlife response to habitat restoration projects. This is particularly true for fragmented habitats in rapidly suburbanizing areas, where the widely held notion that wildlife can colonize any restored habitat is challenged by barriers to dispersal. Because habitat restoration is a passive means of restoring wildlife populations, equal weight needs to be given to the context (likelihood of site colonization by target species) as well as the content (habitat) of restoration projects. Defining spatial patterns of demography, dispersion, and dispersal allows restorationists to place projects where they can have the greatest impact on the threats and sensitivities of target species, and the greatest contribution to the persistence and/or recovery of populations. Further, it provides a means of evaluating the relative potential worth of different restoration sites. If passive wildlife restoration is to be successful, the constraints to colonization need to be interpreted with regional goals of ecosystem and species management in mind.
Microclimatic Changes Induced by Ecological Restoration of Ponderosa Pine Forests in Northern Arizona
Authors: Meyer Cecilia L. , Sisk Thomas D. , Covington W. Wallace 
Published: March 2003

AbstractRestoration of ponderosa pine ecosystems results in altered stand structure, potentially affecting microclimatic conditions and habitat quality for forest organisms. This research focuses on microclimatic changes resulting from forest and landscape structural alterations caused by restoration treatments in southwestern ponderosa pine forests. Three microclimate variables—light intensity, air temperature, and vapor pressure deficit (VPD)—were monitored over two field seasons. Differences in microclimate between the treated forest and the surrounding untreated forest were measured, and microclimatic gradients across the structural edge between these two forest types were quantified. Restoration treatments increased sunlight penetration to the forest floor but did not significantly impact ambient air temperature or VPD. Mean values for air temperature and VPD did not differ significantly between treatments, although temperature and vapor pressure deficit did exhibit a trend in the morning; both variables were higher at the structural edge and in the treated forest during morning hours. Significant edge gradients were detected for air temperature and VPD in the morning and evening, increasing from the structural edge into the untreated forest. Our results show that microclimatic effects of these restoration treatments are generally modest, but the changes are more prominent at specific locations and during certain times of day. Because even modest changes in microclimate have the potential to impact a range of key ecological processes, microclimatic effects should be considered when forest restoration treatments at the landscape scale are being planned and implemented.
Forest Restoration Treatment Effects on the Nesting Success of Western Bluebirds (Sialia mexicana)
Authors: Germaine Heather L. , Germaine Stephen S. 
Published: March 2003

AbstractWe examined the effects of presettlement forest restoration treatments on the nesting success of Western Bluebirds in ponderosa pine forests of northwestern Arizona, U.S.A. From 1998 to 2001 we monitored 97 active Western Bluebird nests, 41 in current‐condition untreated forest and 56 in restoration‐treated forest. We found no effect of restoration treatments on clutch size and little effect on the number of nestlings per nest. However, in treated forest stands number of fledglings per nest averaged 1.6 times greater, and probability of a nest surviving to successfully fledge at least one young was up to 4.2 times greater than in untreated forest. Probability of a nest succeeding averaged 0.39 ± 0.11 (SE) and 0.75 ± 0.06 from 1999 to 2001 in untreated and treated forests, respectively. In addition, in treated forest, average number of nests infested with the blowfly parasiteProtocalliphora sialiawas up to 4.3 times greater, and number of parasites per fledgling was up to 10.7 times greater than in untreated forest. Overall, the data suggest that in treated forest Western Bluebirds have a higher probability of successfully fledging young, but they are at greater risk of parasitic infestations, of which the ultimate effects on post‐fledging survival are unknown.
Soil Nitrogen Pools Associated with Revegetation of Disturbed Sites in the Lake Tahoe Area
Authors: Claassen V. P. , Hogan M. P. 
Published: March 2003

AbstractThin, poorly developed soils in the high elevation, summer‐dry environment near Lake Tahoe, California are easily disturbed by anthropogenic impacts. Subsoils and parent materials that are exposed by vegetation removal and topsoil erosion or by burial during construction activities are difficult to revegetate and may continue to erode for decades after disturbance. The resulting sediment loads contribute to decreased water quality in local watersheds and to the loss of clarity in Lake Tahoe. Field observations suggest that soil disturbance often results in depletion of soil nitrogen (N) reserves and that the remaining substrates may be unable to provide adequate N for revegetation. To quantify the levels of soil N that are associated with higher levels of percent plant cover on previously disturbed soils in the Lake Tahoe area, a basin‐wide survey and a second paired site study were conducted. Results indicate that extractable ammonium and nitrate levels correlate poorly with percent vegetative cover, whereas the correlations of anaerobically mineralizable N and total N are stronger and account for nearly 50% of the variability in plant cover data. Sites with plant cover measuring greater than 40% are associated with total soil N levels of about 1,200 kg N/ha and anaerobic mineralizable N levels of about 26 kg N/ha. Despite high concentrations of N in the surface soils, a large fraction of the N in the 0‐ to 50‐cm profile occurs below 30 cm, when measured on a landscape basis.
Estuarine and Tidal Wetland Restoration in the United Kingdom: Policy Versus Practice
Authors: Pethick John 
Published: March 2003

AbstractRestoration of reclaimed marshes in the United Kingdom, referred to as managed realignment, is both a scientific and a political issue. A cross‐party House of Commons report to Government stressed that provision of long‐term sustainable coastal defenses must start with the premise that “coasts need space” and that government must work to increase public awareness, scientific knowledge, and political will to facilitate such a retreat from the almost sacrosanct existing shoreline. Government, in turn, has agreed with the basis of the report but is aware of conflicting interests, not least the European legislation, which has designated large areas of reclaimed marshes as Special Areas of Conservation that cannot legally be restored to their former tidal processes. Against this background, it is essential that scientific research provides convincing arguments for the necessity for managed realignment, the location, extent, and type of marshlands that need to be restored to provide sustainable flood defenses, maintain and enhance conservation status, and ensure a healthy functioning estuarine system. We examine the political and scientific issues involved, discuss model predictions and field experiments into realignment techniques, and outline the preliminary results of such experiments showing the evolution of restored intertidal wetlands in the United Kingdom.
Season of Burn Influences Fire Behavior and Fuel Consumption in Restored Shortleaf Pine–Grassland Communities
Authors: Sparks Jeffrey C. , Masters Ronald E. , Engle David M. , Bukenhofer George A. 
Published: March 2003

AbstractPine forests of southeastern United States have been burned primarily in the dormant season to accomplish silvicultural objectives, but with increased emphasis on ecosystem restoration fires are now prescribed in other seasons. We observed fire behavior during both growing season and dormant season prescribed fires in shortleaf pine (Pinus echinata) stands managed as pine–grassland communities for the endangered Red‐cockaded Woodpecker (Picoides borealis). Fuel beds for dormant season fires were characterized by lower amounts of live fuels, higher amounts of 1‐hr time lag fuel and a greater total fuel load than growing season fires. Fuel consumption and percent of the total fuels consumed was greater in dormant season fires than in growing season fires. Fireline intensity, heat per unit area, reaction intensity, and rate of spread were greater in dormant season fires than in growing season fires. Lower fire intensity in growing season fires was possibly a function of lower amounts of 1‐hr time lag fuels, higher amounts of live herbaceous fuels, and possibly a less porous fuel bed. Additionally, growing season fires had lower heat per unit area and reaction intensity and slower rates of spread. The Keetch‐Byram drought index (KBDI) did not provide a good index for potential fire behavior on our drought‐prone sandy loam soils. KBDI during growing season fires averaged over four times greater than during dormant season fires, but fire intensity was greater in dormant season fires. Low KBDI values may be misleading and give a false sense of security for dormant season fire prescriptions on sandy loam soils because the duff layer may dry more quickly as a result of inherent low water holding capacity. High KBDI values may result in prescribed burns being canceled because of conditions that are erroneously perceived to be outside the prescription window. We caution against over‐reliance on KBDI as a determining factor for conducting prescribed burns on areas with sandy or sandy loam soils.
Effects of Jack Pine Plantation Management on Barrens Flora and Potential Kirtland's Warbler Nest Habitat
Authors: Houseman Gregory R. , Anderson Roger C. 
Published: March 2003

AbstractJack pine barrens, once common in northern lower Michigan, mostly have been converted to managed jack pine plantations. Management of the disturbances associated with logging provides the opportunity to maintain the unique plant assemblages of jack pine barrens and nest habitat of the federally endangered Kirtland's warbler. Studies indicate thatCarex pensylvanicacan develop into dense mats and strongly compete with other barrens species such asVaccinium angustifolium, which seem to be important species for Kirtland's warbler nest locations. According to forest managers, the most important factors facilitating high cover ofV. angustifoliumand reducing cover ofC. pensylvanicaare the amount of shade produced by tree crowns before harvest (pre‐harvest shade), the length of time between harvest and planting (planting delay), and fire. We found that high or low levels of pre‐harvest shade had no effect on cover of either V. angustifoliumorC. pensylvanica. Planting delays of at least three years following prescribed burns generally increased cover ofV. angustifoliumin forest plots, which are important for warbler nesting. Analysis of community composition in openings indicated that burning enhanced the growth of barrens species. We found only weak evidence for a negative correlation between the cover ofV. angustifoliumandC. pensylvanicaon our study sites. The openings created in the jack pine plantation are important refugia for barrens flora that would likely be lost under forests managed strictly for jack pine. Maintenance of jack pine barrens flora and Kirtland's warbler nest habitat is possible within the context of a heavily managed forest plantation system.
Microbial Community Structure and Carbon‐Utilization Diversity in a Mine Tailings Revegetation Study
Authors: Moynahan October Seastone , Zabinski Catherine A. , Gannon James E. 
Published: March 2003

AbstractRestoration of metals‐contaminated environments requires a functional microbial community for successful plant community establishment, soil development, and biogeochemical cycling. Our research measured microbial community structure and carbon‐utilization diversity in treatment plots from a mine waste revegetation project near Butte, Montana. Treatments included two controls (raw tailings) either (1) with or (2) without tilling, (3) shallow‐tilled lime addition, (4) deep‐tilled lime addition, (5) lime slurry injection, (6) topsoil addition, and (7) an undisturbed area near the tailings. Microbial community structural differences were assayed by plate counts of heterotrophic bacteria, actinomycetes, fungi, and bacterial endospores, and quantification of arbuscular mycorrhizae colonization. Metabolic diversity differences were assessed by carbon‐utilization profiles generated with Biolog microtiter plates. Heterotrophic bacteria counts were significantly higher in the limed and topsoil treatment plots than the control plots, and the actinomycete and fungal counts increased in the tilled control plot as well. Endospore counts were significantly higher in the topsoil addition and the undisturbed plots than the other treatment plots. Carbon‐utilization activity was very low in untreated plots, intermediate in lime‐treated plots, and very high in topsoil and undisturbed plots. Arbuscular mycorrhizae (AM) colonization levels of two grass species showed low levels of colonization on control, shallow‐limed, and lime slurry‐injected plots, and high levels on the deep‐limed and topsoil‐addition plots. Plant and soil system components increased across the treatment plots, but individual components responded differently to changing environmental conditions.
Phytoplankton of a Mississippi River Watershed in Coastal Louisiana
Authors: Ciugulea I. I. , Waters D. A. , Day J. W. , Chapman R. L. 
Published: March 2003

AbstractIn July–August 2001, phytoplankton samples were collected from a coastal marsh south of New Orleans, LA. This wetland area is usually cut off from the Mississippi River by levees and other flood control devices, but periodically the Caernarvon Diversion is opened to allow fresh river water to flow into the marsh. As part of a larger project, the present study seeks to determine the affect the periodic input of freshwater has on phytoplankton dynamics in the Caernarvon Diversion watershed. The first phase of the project ‐ collecting and identifying algae during the summer when the Caernarvon Diversion is kept closed ‐ has been completed. A total of 168 species from 76 genera representing 8 phyla were identified and digital images recorded. Little or no previously published data on the taxonomy and ecology of phytoplankton from this area are available. Sampling in spring 2002, when the diversion is open, will allow comparative analysis of phytoplankton composition and productivity. In a collaborative study, the phytoplankton data will be combined with information on nutrients, chlorophyll a, turbidity, salinity, etc. and used in a model to demonstrate how the ecosystem is affected by the diversion. Also, a database of digital images is available at http://www.chapman.lsu.edu/digitalalgae. In addition to the taxonomic identification data and images, the site will eventually include physico‐chemical and GIS data on the collection sites. Supported in part by a grant from the Office of Sea Grant Development at LSU.
One Small Step: Why Did the Charophytes Have the Right Stuff?
Authors: Delwiche C. F. , Karol K. G. , McCourt R. M. 
Published: March 2003

AbstractThe origin and evolution of land plants (i.e. embryophytes) represents one of the seminal events in the history of life on earth. When the land plant lineage took hold upon the continents, there were profound changes in the global environment including dramatic modification of the erosion regime, correlated changes in marine nutrient inputs, and striking fluctuations in atmospheric chemistry. These changes took place not only because of the ability of land plants to survive on land, but also because their structure and physiology permitted them to make efficient use of resources, anchor themselves effectively and in so doing stabilize the substrate and permit the formation of modern soils, and maintain metabolic activity for long periods of time even in the absence of rainfall and surface moisture. Molecular phylogenetic analyses show the order Charales is the sister group to all land plants, with the Coleochaetales sister to the land plant/Charales lineage. Thus, in a very real sense, the embryophytes are ‘drier algae.’ Many groups of green algae live in the terrestrial environment, but only one of these – the land plants – has radiated into a wide range of habitats. It is not known why the land plant lineage has been so successful. Traits that are likely to have played a role in their success include cell wall biochemistry, desiccation resistance and tolerance, structural complexity, and various reproductive strategies. In all probability, the success of the land plant lineage was not the result of a single ‘key innovation’, but an emergent property resulting from complex interactions among these and other features of the lineage. Comparative study of the properties of diverse aquatic and terrestrial algae can be used to identify properties that were important in the colonization of the land and how they interact.
Algal Stimulation of the Berkeley PIT Lake System
Authors: Bartkowiak B. , Mitman G. G. 
Published: March 2003

AbstractThis study was conducted to evaluate four species of algae (Chromulina freiburgensis Dofl., Chlorella ellipsoidea Gerneck, C. vulgaris Beijerinck, and Chlamydomonas acidophila Negoro) isolated from an acid pit lake for their bioremediative potential. The Berkeley Pit Lake system, located in Butte, MT, USA is an abandoned open‐pit mine. As a result of acid rock drainage the water in this pit is very acidic and contains high concentrations of dissolved metals. First, optimal nutrient levels for each species of algae were determined. Levels of nutrients tested include: 5, 10, 15 mg N/L, and 0, 3, 6 mg P/L. The experiment was conducted with sterile filtered Berkeley Pit water. Next, each species of algae were grown under optimal nutrient levels and dissolved metal removal potentials were examined, using Inductively‐Coupled Plasma–Atomic Emission Spectrometry (ICP–AES). In addition, field sampling was preformed to gain a better understanding of the microbial community within the pit. Finally, field parameters including, light, temperature, dissolved oxygen, specific conductivity, redox potential, and turbidity were examined to determine the actual conditions for microbial growth within the Berkeley pit.
The Aquaculture of Porphyra Leucosticta (Rhodophyta) for an Integrated Finfish/Seaweed Recirculating Aquaculture System in an Urban Application
Authors: Yarish C. , He P. , Carmona R. , Liu S. , Kraemer G. , Neefus C. , Chopin T. , Nardi G. , Curtis J. , Lonergan S. , Trupp P. 
Published: March 2003

AbstractAquaculture represents an excellent opportunity to help rejuvenate blighted coastal urban areas on the north‐east coast. Aquaculture requires relatively little space, often acquired at reduced cost in ungentrified city areas, and can represent an attractive, environmentally benign form of commerce. However, finfish and shellfish aquaculture operations are a source of an effluent with high concentrations of dissolved inorganic nutrients (N, P). To prevent eutrophication, the EPA is developing stringent guidelines for the release of N and P into coastal waters. An integrated recirculating aquaculture system, coupling the growth of seaweed and fish, can solve these problems for urban aquaculture facilities; not only is the effluent remediated but an additional multiproduct, high‐value crop can be generated. One tank‐based (on land) marine aquaculture operation is GreatBay Aquaculture, LLC (Portsmouth, NH), a land‐based hatchery and grow‐out facility for high value summer flounder and cod. Our work is to develop an integrated finfish/seaweed recirculating aquaculture system (RAS) suitable for urban aquaculture. Our RAS system will integrate the culture of summer flounder and native species of seaweed (i.e. Porphyra). BRVAS students are working along side undergraduate and graduate students in the construction and operation of these systems. There are at least seven recognized species of Porphyra in the north‐east. We have begun mesoscale evaluation of P. leucosticta, since it may be a good candidate for the food (sushi) and for r‐phycoerythrin industries. The mass culture techniques (in both free culture and attached to nets) for this Porphyra species are developing. We will report on the mass seeding technologies that we have developed and the specific growth rates of P. leucosticta at the BRVAS culture facilities.