bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seed Banks and Species Richness Potential of Coal Slurry Ponds Reclaimed as Wetlands
Authors: Middleton Beth A. 
Published: April 2006

AbstractSeed bank experiments are described to assess the species richness potential of coal slurry ponds reclaimed as wetlands (ranging from 6 to more than 40 years old). Experimental treatments test the drawdown and flooded conditions characteristic of the vegetation dynamics of emergent wetlands in the Upper Mississippi Valley. More seedlings, primarily annuals, emerged from exposed wet sediments (freely drained) than under continuous flooded sediments in cold ponds (339 versus 136 seedlings m−2, respectively) and in natural ponds (163 versus 47, respectively). More seeds were produced by plants established in freely drained conditions than under flooded conditions from sediments in the coal ponds (26546 versus 1842 seeds m−2, respectively) and the natural ponds (28430 versus 4526, respectively). Similarly, more biomass was also produced by these plants in freely drained than under flooded conditions in coal ponds (118 versus 47 g m−2, respectively) and natural ponds (118 versus 52, respectively). Fertilization (NPK) did not affect germination for the most part, but it did affect seed set and biomass production, especially for C4 annuals such as Echinochloa crusgalli and Panicum dichotomiflorum. I propose that lime (calcium carbonate) and fertilizer be applied during the first few scheduled drawdowns for these coal slurry ponds reclaimed as wetlands to increase the number of species and to allow their more rapid development as self‐sustaining systems.
A Model for Aquatic Invertebrate Response to Kissimmee River Restoration
Authors: Harris Steven C. , Martin Thomas H. , Cummins Kenneth W. 
Published: April 2006

AbstractWhen the Kissimmee River was channelized in the 1960s and 1970s and placed under stage‐fluctuation management, the dynamic interactions between the river and the flood‐plain were essentially removed. Correspondingly, aquatic invertebrate life in the river and floodplain ecosystem shifted from a riverine to a more lacustrine fauna. A relinkage of the Kissimmee River with the floodplain following restoration will result in numerous changes to such ecologically important factors as streamflow, substrate composition, food quality and quantity, and water quality, all of which will influence invertebrate communities. These factors and their function in the ecosystem as the fauna shifts from predominantly lacustrine back to riverine are presented in a conceptual model. As an integral component of all aquatic ecosystems and a key link between primary producers and higher trophic levels, aquatic invertebrates are a valuable group with which to evaluate the recovery of the Kissimmee River. Utilization of a geographic information system mapping approach linking expected increased habitat heterogeneity and invertebrate richness with restoration efforts is suggested as an economical means of monitoring recovery of the Kissimmee River ecosystem.
Ineffectiveness of Two Annual Legumes as Nurse Plants for Establishment of Artemisia californica in Coastal Sage Scrub
Authors: Marquez Viviane J. , Allen Edith B. 
Published: April 2006

AbstractAnnual legumes are often used as nurse plants for restoration projects, but two commonly used legume species were competitors at all densities with Artemisia californica (California sagebrush), a dominant shrub of southern California coastal sage scrub. Survival of Artemisia was not reduced by the lowest densities of the native Lupinus succulentus (arroyo lupine) at ratios of Artemisia to Lupinus of 1:1 or 1:3 or by the exotic Trifolium hirtum (rose clover) at the 1:1 density, but its survival was as low as 4% at the highest densities of Trifolium (1:16) and 1:32). Overall, Trifolium was more detrimental to survival of Artemisia, but the biomass of Artemisia was reduced by 90% or more in mixtures with both legumes even at the lowest densities of 1:1. The total soil nitrogen either did not change or decreased in two of the mixtures between planting and harvest dates, indicating that the legumes not only did not add nitrogen to the soil within one growing season but even depleted it in these two cases. Whereas Lupinus had greater aboveground bio‐mass than Trifolium, it had a lower root density than Trifolium. The Artemisia root system was more shallow than either Trifolium or Lupinus, possibly explaining the poor growth of Artemisia in mixtures, The legumes were one to two orders of magnitude greater in aboveground biomass than Artemisia at the 1:1 ratio and therefore may be inappropriate choices as nurse plants. There is no evidence from this study that either of these legumes can act as nurse plants, even at the lowest ratio of one nurse plant to on shrub. Nurse plants are probably more important in harsher environments than in coastal sage scrub.
Towards a Conceptual Framework for Restoration Ecology
Authors: Hobbs Richard J. , Norton David A. 
Published: April 2006

AbstractHeightening human impacts on the Earth result in widespread losses of production and conservation values and make large‐scale ecosystem restoration increasingly urgent. Tackling this problem requires the development of general guiding principles for restoration so that we can move away from the ad hoc, site‐ and situation‐specific approach that now prevails. A continuum of restoration efforts can be recognized, ranging from restoration of localized highly degraded sites to restoration of entire landscapes for production and/or conservation reasons. We emphasize the importance of developing restoration methodologies that are applicable at the landscape scale. Key processes in restoration include identifying and dealing with the processes leading to degradation in the first place, determining realistic goals and measures of success, developing methods for implementing the goals and incorporating them into land‐management and planning strategies, and monitoring the restoration and assessing its success. Few of these procedures are currently incorporated in many restoration projects. The concept that many ecosystems are likely to exist in alternative stable states, depending on their history, is relevant to the setting of restoration goals. A range of measures, such as those being developed to measure ecosystem health, could be used to develop “scorecards” for restoration efforts. Generalizable guidelines for restoration on individual sites could be based on the concepts of designed disturbance, controlled colonization, and controlled species performance. Fewer explicit guidelines are available at the landscape scale, beyond nonquantitative generalities about size and connectivity. Development of these guidelines is an important priority so that urgent large‐scale restoration can be planned and implemented effectively.
Implications of Seedling Emergence to Site Restoration following Bauxite Mining in Western Australia
Authors: Grant Carl D. , Bell David T. , Koch John M. , Loneragan William A. 
Published: April 2006

AbstractSeedling emergence of 12 selected northern jarrah (Eucalyptus marginata Donn ex Smith) forest species were investigated to assist Alcoa of Australia Ltd. in maximizing the establishment of topsoil species in rehabilitated bauxite mining sites. The species, which encompassed a range of seed weights (0.024 mg to 87 mg), plant families, seed‐storage types, life forms, and germination requirements, were placed on the soil surface and at depths of 1, 2, 5, 10, and 15 cm under controlled conditions in a glasshouse. Ability to emerge from deep burial was found to depend on seed size for species that annually release their seed to the topsoil but not for species that store their seed on the plant. All selected species were capable of emerging from 2 cm depth of burial, but eight of the 12 species were either unable to emerge from 5 cm or showed a significant reduction in emergence from 5 cm depth of burial compared to optimally buried seed. This group included two small‐seeded species, Stylidium calcaratum and Chamaescilla corymbosa; the major forest dominant, Eucalyptus marginata; the serotinous canopy‐borne seed of Hakea amplexicaulis; and the wind‐dispersed seed of Xanthorrhoea gracilis. A few seeds of the legume species Kennedia coccinea, Acacia pulchella, and Bossiaea aquifolium established seedlings from depths of 15 cm. Currently, Alcoa removes the upper 15 cm of topsoil separately from the underlying soil prior to the commencement of mining. This topsoil is respread at a similar depth following mining as part of the rehabilitation procedure. It is recommended that Alcoa continue to strip topsoil to a depth of 15 cm but investigate the option of re‐spreading topsoil onto rehabilitated pits at a shallower depth to maximize establishment via the soil seed bank.
Population Genetic Analyses of Transplanted Eelgrass (Zostera marina) Beds Reveal Reduced Genetic Diversity in Southern California
Authors: Williams Susan L. , Davis Christopher A. 
Published: April 2006

AbstractSeagrass ecosystems fulfill ecologically and economically valuable functions in coastal marine environments. Unfortunately, seagrass beds are susceptible to natural and human disturbances, and their distrubution is declining worldwide. Although intentional disturbance of seagrass beds must be mitigated pursuant to U.S. law, to date mitigation of seagrass beds has not prevented a net loss of habitat. Transplantation of vegetative material from small areas of nearby beds is the primary method of seagrass mitigation. Restoration research on seagrasses has focused primarily on establishment of the plants and secondarily on the functional equivalency of the habitats. We questioned whether transplanted seagrass beds were comparable to “natural” beds in terms of genetic diversity and structure. We sampledZostera marinaL. (eel‐grass) from 12 sites in the highly urbanized area of San Diego County and from pristine sites in Baja California. Using allozyme electrophoresis, we determined that genetic diversity (percentage of polymorphic loci, allele richness, expected and observed heterozygosities, and proportion of genetically unique individuals) was significantly reduced in transplanted eelgrass beds. Eelgrass from Baja California exhibited the highest genetic diversity. Based on Wright's F statistics, most of the genetic variation was distributed within rather than among sites (FST= 0.139), and the degree of genetic structure was only moderate at the greatest geographical scale (San Diego—Baja). Using a spatial statistical analysis (second‐order analysis), we found virtually no evidence for nonrandom distribution of alleles or genotypes at scales of 3–50 m within beds. We discuss several hypotheses for reduced genetic diversity in transplanted eelgrass beds, including transplantation protocol, small size of transplantations, and reduced or failed sexual reproduction.
Macroinvertebrate Responses to Mitigative Liming of Dogway Fork, West Virginia
Authors: Clayton Janet L. , Menendez Raymond 
Published: April 2006

AbstractDogway Fork, West Virginia, is a second–order stream affected by acid precipitation. One goal of the Acid Precipitation Mitigation Program was to determine if the composition or population levels of benthic macroinvertebrates were affected by limestone neutralization of the acidic waters (pH 4.5). Two techniques were used to determine any effects: seasonal Surber samples and in situ bioassays with selected genera. Prior to treatment, macroinvertebrate densities were low but represented a diverse group of acidtolerant taxa. During treatment, fewer macroinvertebrates were collected in the treated segment than in the untreated control. This appears to be a result of a number of factors, including substrate, flows, drift, fish predation, accumulation of limestone fines, and changes in water chemistry. Bioassays suggest that the limestone fines were not directly detrimental to the organisms but may have limited available habitat in the mixing zone. Limestone treatment affected the species composition of Dogway Fork. During four years of treatment, several new acid‐sensitive taxa were collected in the treated segment. Data suggest that, with continued treatment, populations of these taxa can be expected to increase.
Impact of a Protective Limestone Treatment on the Water Chemistry and Zooplankton Community of Thrush Lake, Minnesota
Authors: Wright David , Danks Marilyn , Lawrenz Ron 
Published: April 2006

AbstractA limestone slurry was sprayed on the surface of Thrush Lake, a small headwater lake in northeastern Minnesota, to test a treatment designed to protect acid‐sensitive waters from anthropogenic acidification. The 6‐year study, consisting of pretreatment, transition, and post‐treatment phases, was part of the four‐state Acid Precipitation Mitigation Program directed by the U.S. Fish and Wildlife Service. Measured water‐chemistry parameters, including acid‐neutralizing capacity, pH, dissolved calcium, and dissolved inoroganic carbon, increased following treatment, although local climatic conditions influenced the magnitude and duration of the chemical changes. Physical changes to the lake, other than an increase in conductivity and a short‐term alteration of water clarity subsequent to treatment, were not documented. The composition of the zooplankton community was altered, with the proportion of rotifers increasing after treatment. Individual zooplankton species showed a variety of changes in abundance that were associated with treatment over both seasonal and multi‐year intervals. For example, Holopedium gibbemm was absent from lake samples immediately following treatment and recovered within a season, whereas Diaptomus minutus and Keratella taurocephala populations were reduced after treatment and had not recovered by the end of the study. Alternately, Asplanchna priodonta increased in abundance after treatment. These observed abundance patterns were generally consistent with previzous acidification or base‐addition studies. In contrast, the changes in community composition of zooplankton did not consistently fit patterns developed from regional studies across water‐chemistry gradients. These differences emphasize the importance of biotic as well as abiotic factors in controlling zooplankton community composition.
An Evaluation of Habitat Rehabilitation on Coastal Dune Forests in Northern KwaZulu‐Natal, South Africa
Authors: van Aarde R. J. , Ferreira S. M. , Kritzinger J. J. , van Dyk P. J. , Vogt M. , Wassenaar T. D. 
Published: April 2006

AbstractThe rehabilitation program conducted by Richards Bay Minerals (RBM) of areas exposed to opencast surface mining of sand dunes north of Richards Bay (28°43'S, 32°12'E) on the coast of northern KwaZulu‐Natal Province commenced 16 years before this study and has resulted in the development of a series of known‐aged stands of vegetation. By assuming that these spatially separated stands develop along a similar pathway over time, instantaneous sampling should reveal successional or other changes usually associated with aging and should provide an opportunity to evaluate the success of rehabilitation. We compare relative densities of pioneer and secondary species, species richness, and a similarity index of the herbaceous layer, tree, beetle, millipede, bird, and small‐mammal communities of rehabilitating areas of known age with those of 30‐year‐old unmined forests and unmined forests of unknown age adjacent to the rehabilitating area. Species richness for all but the mammalian taxa increased with increasing age of rehabilitating stands. For all taxa but the mammals and herbaceous layer, the unmined stands harbored more species than the mined rehabilitating stands. The relative densities of pioneer species of all the taxa decreased with an increase in the age of rehabilitating stands, whereas those of the secondary species increased with an increase in habitat age. Similarity between unmined stands and rehabilitating stands of different ages increased with increasing regeneration age of rehabilitating stands, suggesting that rehabilitating communities, in terms of species composition and relative densities, are developing towards the status of unmined communities. Rehabilitation based on RBM's management program of limited interference is occurring and may result in the reestablishment of a coastal dune forest ecosystem. But rehabilitation resulting from succession depends on the availability of species sources from which colonization can take place. In the Richards Bay mining operation the present mining path is laid out so that such refuges are present.
Rehabilitation of Semiarid Landscapes in Australia. II. Restoring Vegetation Patches
Authors: Ludwig J. A. , Tongway D.J. 
Published: April 2006

AbstractThis paper describes a practical technique, tested experimentally, for rehabilitating degraded semiarid landscapes in Australia. This rehabilitation technique is based on the ecological principle that semiarid landscapes are spatially organized as patchy, source‐sink systems; this patchy organization functions to conserve limited water and nutrients within the system. The aim was to rebuild vegetation patchiness, lost through decades of utilization of these landscapes as rangelands. Patches were reconstructed from large tree branches and shrubs obtained locally and placed in elongated piles along contours. These piles of branches were very effective in recreating productive soil patches within the landscape, as described in part I of this study. These new patchy habitats promoted the establishment and growth of perennial grasses. Although the foliage cover of these grasses declined into a drought, which started before the end of the experiment, plant survivorship remained high. This suggests that patches also function as refugia for organisms during droughts. The patches of branches remained robust and functional, even under grazing impacts, although plant growth and survival were significantly higher within an ungrazed paddock than in a grazed paddock.
Setting Objectives and Defining Outputs for Ecological Restoration and Habitat Creation
Authors: Box John 
Published: April 2006

AbstractThe past 40 years have seen the legal and policy framework for nature conservation in Britain extend from protection and preservation to include enhancement through techniques such as ecological restoration and habitat creation. Clear objectives need to be set for ecological restoration and habitat creation schemes because the processes involve human intervention in combination with natural factors operating over time. Objectives are required for both management and monitoring in order to enable measurement of success or failure. The most effective way to achieve high‐quality restoration and creation schemes is to define the output of the process—a habitat, vegetation type, or biological community. The better the definition of the output, the greater the need to define the inputs and the nature of the intervening processes. Ecologists and environmental managers have a key role to play in establishing the degree of definition necessary in order to achieve a particular objective.
Chlorhexidine mouthrinse in combination with an SLS‐containing dentifrice and a dentifrice slurry
Authors: Van Strydonck D. A. C. , Timmerman M. F. , Van der Velden U. , Van der Weijden G. A. 
Published: April 2006

AbstractObjectives: The aim of the present study was to compare the plaque‐inhibitory effect of a 0.2% chlorhexidine digluconate (CHX) rinse when preceded by ordinary toothbrushing with a 1.5% sodium lauryl sulphate (SLS)‐containing dentifrice to the effect of the same rinse when used alone, or when preceded by rinsing with an SLS‐containing slurry.Methods: The study was an examiner blinded, randomized three‐arm, parallel design. It used a 4‐day plaque accumulation model to compare three different oral hygiene regimens, which were performed under supervision. One hundred and twenty healthy volunteers were enrolled in the study and were randomly assigned to one of each group. At the beginning of each test period, they received a thorough dental prophylaxis. The experiment was performed in one randomly assigned (upper or lower) jaw, called the study jaw. The opposite jaw, referred to as the dentifrice jaw, served only to introduce the influence of toothbrushing with a dentifrice on the anti‐plaque efficacy of the CHX in the study jaw of the same mouth. At the end of the 4‐day test period, plaque and gingival bleeding were scored in the study jaw. In all the regimens, the oral hygiene procedure was finalized by rinsing with a CHX 0.2% solution for 1 min. The study jaw was not brushed during the experiment. Regimen A (positive control) consisted of rinsing with CHX alone. In regimen B, rinsing with CHX was preceded by rinsing with an SLS‐containing slurry, while in regimen C rinsing with CHX was preceded by toothbrushing with an SLS‐containing dentifrice in the dentifrice jaw. No other oral hygiene measures were allowed. After 4 days of undisturbed plaque accumulation, the amount of plaque and level of gingival health were evaluated.Results: The overall plaque index for regimens A, B and C was 1.17, 1.62, and 1.14, respectively. There was no significant difference in plaque accumulation between the CHX alone regimen (A) and the SLS–dentifrice–CHX regimen (C). Regimen B differed significantly from regimens A and C. The overall bleeding index for regimens A, B and C was 0.24, 0.18, and 0.20, respectively. There was no significant difference between the three regimens.Conclusions: The present study shows that the anti‐plaque efficacy of a 0.2% CHX rinse was not reduced when preceded by everyday toothbrushing with a SLS‐containing dentifrice. However, when preceded by rinsing with an SLS‐containing slurry, the anti‐plaque efficacy of a 0.2% CHX rinse was reduced.
Topical minocycline microspheres versus topical chlorhexidine gel as an adjunct to mechanical debridement of incipient peri‐implant infections: a randomized clinical trial
Authors: Renvert Stefan , Lessem Jan , Dahlén Gunnar , Lindahl Christel , Svensson Marie 
Published: April 2006

AbstractAim: This randomized clinical trial presents a 12‐month follow‐up of the clinical and microbiological results after application of minocycline microspheres as an adjunct to mechanical treatment of incipient peri‐implant infections compared with an adjunctive treatment using 1% chlorhexidine gel application.Material and Methods: Thirty‐two subjects with probing depth 4 mm, combined with bleeding and/or exudate on probing and presence of putative pathogenic bacteria were given oral hygiene instructions and mechanical treatment of infected areas adjacent to implants. The subjects were then randomly assigned adjunctive subgingival antimicrobial treatment using either chlorhexidine gel or minocycline microspheres. Sixteen patients in the minocycline group and 14 in the chlorhexidine group completed the study. Follow‐up examinations were carried out after 10 days, 1, 2, 3, 6, 9 and 12 months.Results: The adjunctive use of minocycline microspheres resulted in improvements of probing depths and bleeding scores, whereas the adjunctive use of chlorhexidine only resulted in limited reduction of bleeding scores. For the deepest sites of the treated implants in the minocycline group, the mean probing depth was reduced from 5.0 to 4.4 mm at 12 months. This study could not show any significant difference in the levels of bacterial species or groups at any time point between the two antimicrobial agents tested. The present findings encourage further studies on adjunctive use of minocycline microspheres in the treatment of peri‐implant lesions.Conclusions: The use of a local antibiotic as an adjunct to mechanical treatment of incipient peri‐implantitis lesions demonstrated improvements in probing depths that were sustained over 12 months.