bluuebunny/crossref_metadata_2025_split huggingface dataset:
A multi‐site assessment of the effectiveness ofPteridium aquilinumcontrol in Great Britain
Authors: Cox E.S. , Marrs R.H. , Pakeman R.J. , Le Duc M.G. 
Published: July 2009

AbstractQuestions:The objectives of this study were to assess the effect ofPteridium aquilinum(bracken) control treatments, at the national scale, and the impact of restoration practices, at the local scale, onP. aquilinumperformance.Hypotheses:1. Geographical location (locally between and within sites) affects the control ofP. aquilinumthrough time. 2. Are theP. aquilinumcontrol treatments successful at all sites, and if so which ones? 3. The treatments applied at the individual site level to restore vegetation influences the performance ofP. aquilinumthrough time.Location:Four geographically distinct acid grassland and heathland sites infested withP. aquilinumacross Great Britain.Methods:Six main‐plot, bracken control treatments were applied to all sites with site‐specific vegetation restoration treatments. Response variables (P. aquilinumcover, frond length and density) were monitored twice yearly, in June and August between 1993 and 2003.Results:Between‐ and within‐site spatial variation was found, although impact is perhaps less than suggested from shorter‐term data. Despite local variation all sites responded similarly to bracken control treatments; asulam treatment resulted in a rapid reduction in frond performance followed by a continued recovery taking approximately ten years to return to untreated values. Cutting treatments tended to have a slower impact at the start but an increasing one over time, especially cutting twice per year. Restoration treatments had a limited impact; the only significant effect in August was grass seeding on frond length at Sourhope. In June only, the plots where sheep were fenced out showed a significant reduction inP. aquilinumcover at Peak.Conclusions:Long‐term control ofPteridium aquilinumat all sites and on all measures was best achieved using a continuous cutting treatment, preferably twice per year.
Effects of topsoil removal, seed transfer with plant material and moderate grazing on restoration of riparian fen grasslands
Authors: Rasran L. , Vogt K. , Jensen K. 
Published: July 2009

AbstractQuestion: How do moderate grazing, topsoil removal and hay transfer affect species diversity and abundance on a eutrophic fen grassland site?Location: Northern Germany.Method: A three‐factorial field experiment with the factors grazing, topsoil removal and hay transfer of diaspore‐rich material was established in 2001. Soil nutrients and seed bank were analysed at the beginning of the experiment, species composition and vegetation development was monitored for four years (2002–2005).Results: Topsoil removal had a significant effect on the abundance of different plant species groups: resident vegetation of agricultural grasslands was suppressed, while clonal reed species were facilitated in recolonising the area. The establishment of regionally rare and endangered species of nutrient‐poor fens and wet meadows introduced with hay was achieved mainly on plots with topsoil removal, with the exception of Rhinan‐thus angustifolius, which also established on plots with intact topsoil. Effects of grazing after four years of experiments were of minor influence on species composition.Conclusion: The establishment of target plant species of nutrient‐poor fens is most successful when both an adequate number of viable diaspores and suitable sites for germination and establishment are available. In our experiment this was achieved by the combination of topsoil removal and hay transfer. We recommend this combination, together with continuous management (grazing/cutting), for further restoration in fen grasslands.
The spatial relationship between post‐crop remaining trees and the establishment of saplings inPinus sylvestrisstands in Spain
Authors: Montes F. , Cañellas I. 
Published: July 2009

AbstractQuestion:What is the spatial relationship between remaining trees and the establishment and development of recruited saplings?Location:ThePinus sylvestrisforestPinar de Valsaín, in the Sistema mountain range (central Spain).Methods:Three 0.5 ha plots have been analysed. The saplings were located in a 2 m x 2 m grid, characterizing their spatial pattern through a nested ANO VA. The spatial pattern of stems was analysed using theL(d)function. To analyse the spatial relationship between stems belonging to different cohorts, the intertypeLrs(d)function was used. Finally a new functionKrx(d)is presented as a method to analyse the relationship between the spatial distribution of stems and the sapling density (a sampled continuous variable).Results:The mother trees show cluster pattern at scales of ca. 12 m ‐ 22 m, leading to a spatial pattern at 14 m–16 m for the saplings during the regeneration period. At the beginning of the shelter phase, saplings less than 1.30 m in height show spatial repulsion from the old crop at distances above 10 m, whereas taller saplings show repulsion at shorter distances, due to the suppression of sapling development near the mother trees. At the end of the regeneration period, saplings < 1.30 m appear under the last remaining mother tree canopies.Conclusions:In the stands analysed, located at the southern limit ofPinus sylvestrisdistribution, this species behaves as half‐shade tolerant. This study shows that theKrx(d)function might be widely applied to analyse the relationship between patterns that occur at different scales or between a point pattern and a continuous variable, being a useful tool for analysing some forest processes.
Optimal management of the rare Gladiolus imbricatus in Estonian coastal meadows indicated by its population structure
Authors: Moora Mari , Kose Marika , Jõgar Ülle 
Published: July 2009

AbstractQuestions: What is the best grassland management regime for the threatened plant species Gladiolus imbricatus; is the stage structure of local populations a feasible indicator of the effect of changed management.Location: Coastal meadow system in southwestern Estonia. Methods: The effect of five management regimes was studied in a long‐term (three‐year) field experiment: (1) mowing in late July, (2) grazing by cattle, (3) grazing by sheep, (4) sheep grazing during the first year and mowing during subsequent years, (5) no management (control).Results: The population density increased significantly in response to the mowing treatment and to the mowing after sheep grazing treatment. The proportion of grazed plant individuals was higher in the sheep‐grazed than in the cattle‐grazed treatment. Generative and vegetative adult individuals of G. imbricatus were significantly more damaged by cattle herbivory than juveniles. All management regimes shifted the population structure towards a dynamic state where juvenile stages dominate, while the not managed control retained a regressive population structure.Conclusions: Population stage structure was a useful indicator of different management conditions, even in the case where population density did not differ. As indicated by population stage structure, the best management regime for G. imbricatus was either mowing in late July only, or alternation of grazing and mowing in different years.
Improving predictive mapping in Swiss mire ecosystems through re‐calibration of indicator values
Authors: Feldmeyer‐Christe Elizabeth , Ecker Klaus , Küchler Meinrad , Graf Ulrich , Waser Lars 
Published: July 2009

AbstractQuestion: How may Landolt indicator values be re‐calibrated to improve the performance of predictive models?Location: Mires Gross Moos Schwändital (1250 m a.s.l.) in the Prealps, Burgmoos (465 m. a.s.l.) on the Central Plateau and La Burtignière (1000 m a.s.l.) in the Jura, Switzerland.Methods: Habitat distribution models based on high resolution remotely sensed data and vegetation field data are applied to monitor 130 mires. Instead of plant species or communities we used mean indicator values of vegetation records as response variables. To improve the differential power of indicator values for wetland habitat conditions, we calibrated these values using field data. Different methods were tested with our predictive models in three mires to see which calibration method is best in enhancing model performance. To assess the effect of the uneven distribution of vegetation records along environmental gradients, calibrations based on random and evenly distributed samples were compared. As a test of the predictive power of the models we used r2 between ground truth and model prediction.This approach is illustrated through an application with nutrient indicator values in the mire La Burtignière. Results: Model performances were not the same for the three mires. The predictive power was better for the nutrient values, soil reaction and humus values than for light and moisture values. 2000 records were sufficient as basis for re‐calibration. Models based on original Landolt indicator values were overall the weakest compared with re‐calibrated values. By comparing the predictive power of Models based on randomly or evenly selected records were about equally predictive.Conclusions: 1. Ahabitat‐specific re‐calibration of the Landolt indicator values enhances the predictive mapping of the Swiss mire ecosystems. 2. The re‐calibration based on weighted averaging gives a better performance than the one based on Gaussian logistic regression. 3. The uneven distribution of indicator values due to the over‐representation of mire habitats does not hamper model performance. 4. 2000 vegetation records are a sufficient basis for an optimal re‐calibration of the vegetation types. An illustration of the method is given by using the soil fertility pattern of the mire La Burtignière.
Monitoring succession from space: A case study from the North Carolina Piedmont
Authors: McDonald Robert I. , Halpin Patrick N. , Urban Dean L. 
Published: July 2009

AbstractQuestion: Is the successional transition from pine to hardwood, which has been inferred from chronosequence plots in previous studies, validated through a time line of satellite imagery?Location: Durham, North Carolina, USA.Methods: We examined successional trends in a time‐series of winter‐summer pairs of Thematic Mapper imagery from 1986 to 2000. We calculated the normalized difference of vegetation index (NDVI) for winter and summer, as well as the difference between summer and winter NDVI (i.e., summer increment NDVI). A set of approximately 50 forest stands of known age and phenology were used to interpret patterns in winter and summer increment NDVI over successional time, and a continuum was found to exist between pine‐dominance and hardwood‐dominance. We fitted a series of linear regressions that modeled the change in winter and summer increment NDVI as a function of initial winter and summer increment NDVI, and additional explanatory variables.Results: All regressions were highly significant (P < 0.0001, R2= ca. 0.3). Predicted dynamics are in accord with successional theory, with pixels moving from evergreen dominance to deciduous dominance along a line of fairly constant summer NDVI. A large disturbance event that occurred over the course of this study, Hurricane Fran, appeared to slow rates of succession in the short term (1–3 years), but increase the rate of conversion to hardwoods over longer time spans.Conclusions: We conclude that temporal sequences of remote sensing images provide an excellent opportunity for broad‐scale monitoring of successional processes, and that continuous metrics of that change are essential to accurate monitoring.
Improving knowledge of urban vegetation by applying GIS technology to existing databases
Authors: Altobelli A. , Bressan E. , Feoli E. , Ganis P. , Martini F. 
Published: July 2009

AbstractQuestion: Can we improve the knowledge of urban vegetation using data from ongoing floristic and management projects with a data mining approach? We have two questions: 1. How strong is the relationship between land cover pattern and the species composition of vegetation? 2. What is the relationship between land cover pattern and species richness?Location: Trieste, northeastern Italy.Methods: Using land cover maps and GIS we characterized the cells of a floristic project grid by percentage cover of land cover types. We applied Canonical Correlation Analysis to test the correlation between floristic composition of the cells and land cover. We classified the cells by clustering methods, based on land cover description. With these clusters, we analysed the variation of species composition of urban vegetation along a gradient of urban density. We used Jaccard's similarity index to compare floristic composition of the clusters with the floristic composition of the homogeneous cells with respect to the land cover types. To answer question 2, we calculated land cover heterogeneity with the Shannon index and correlated the number of species in clusters with land cover heterogeneity and urban density.Results: Each land cover type contributes to species richness and species composition of the clusters. Species richness decreases significantly and linearly as urban density increases and land cover heterogeneity decreases in the clusters.Conclusions: A data mining approach can combine different existing projects to improve knowledge of the urban vegetation system. The methods we have applied offer tools to answer the specific questions mentioned above.
Facilitation and interference underlying the association between the woody invaders Pyracantha angustifolia and Ligustrum lucidum
Authors: Tecco P.A. , Díaz S. , Gurvich D.E. , Perez‐Harguindeguy N. , Cabido M. , Bertone G.A. 
Published: July 2009

AbstractQuestions: 1. Is there any post‐dispersal positive effect of the exotic shrub Pyracantha angustifolia on the success of Ligustrum lucidum seedlings, as compared to the effect of the native Condalia montana or the open herbaceous patches between shrubs? 2. Is the possible facilitation by Pyracantha and/or Condalia related to differential emergence, growth, or survival of Ligustrum seedlings under their canopies?Location: Córdoba, central Argentina.Methods: We designed three treatments, in which ten mature individuals of Pyracantha, ten of the dominant native shrub Condalia montana, and ten patches without shrub cover were involved. In each treatment we planted seeds and saplings of Ligustrum collected from nearby natural populations. Seedlings emerging from the planted seeds were harvested after one year to measure growth. Survival of the transplanted saplings was recorded every two month during a year. Half of the planted seeds and transplanted saplings were cage‐protected from rodents.Results:
Ligustrum seedling emergence did not differ among treatments while growth was significantly higher in the absence of shrub cover. Sapling survival was significantly higher under the canopy of Pyracantha, intermediate under Condalia, and lowest in the absence of shrub cover. Caging did not affect growth but enhanced seedling emergence and sapling survival.Conclusion: The differential sapling survival in the shrub canopy treatments is consistent with natural sapling distribution. Pyracantha and, less so, Condalia, has a nurse‐plant effect on Ligustrum. This results from contrasting effects of the shrubs on different stages of the life cycle of Ligustrum: no effect on seedling emergence, negative on seedling growth, and positive on sapling survival. This suggests that efforts to control the expansion of Ligustrum over the landscape should tackle Pyracantha as well.
Regional species pools of hay meadows: A case study
Authors: Losvik Mary H. 
Published: July 2009

AbstractQuestions: Is it possible to render the species pool concept operational for cultural landscape management and restoration?Location: Hordaland and Sogn & Fjordane counties, western Norway.Methods: An initial regional species list, based on information on the distribution of species and habitats in the Norwegian flora, was filtered using information on target communities and species lists from 95 sites in the region. Owing to the importance of both mowing and grazing Ellenberg indicator values were not used in the identification process.Results: The final regional species pool consisted of 227 species, of which 194 were extracted from the flora, while 33 agricultural landscape species were added from the actual pool or from a list of species in additional hay meadows. Some of the 33 species were regular inhabitants of hay meadows, others were rare in the region. The regional species pool list includes information on each species on demands when hydrology, nutrients and base saturation in the soil is concerned, and whether or not they are characteristic for either of the boreal or boreo‐nemoral vegetation zones.Conclusions: Specialist knowledge was an advantage when adding cultural landscape species other than meadow species of the flora; 77 species were documented only by the flora, interesting from the point of view of restoration as this part of the pool would not have been found by just adding species lists. The diversity of the now isolated hay meadow sites in the region may be kept up by replacing the lost natural invasion by an artificial one, using local seed mixtures and transplants.
Prescribed fires in Artemisia tridentata ssp. vaseyana steppe have minor and transient effects on vegetation cover and composition
Authors: Seefeldt Steven S. , Germino Matthew , DiCristina Katherine 
Published: July 2009

AbstractQuestion: What is the impact of prescribed fires on the cover and composition of vegetation in Artemisia tridentata ssp. vaseyana steppe?Location: United States Department of Agriculture, Agricultural Research Service, United States Sheep Experiment Station, eastern Idaho (44°14′44′’ N, 112°12′47′’ W).Methods: Multiple prescribed fires were lit in 2002 and 2003 in an Artemisia tridentata ssp. vaseyana (mountain big sagebrush) steppe ecosystem that was relatively free of exotic plants. Measurements of cover components and plant species frequencies were taken pre‐ and for 2 to 3 years post‐fire.Results: Cover of forbs and grasses returned to pre‐fire levels after two years. Shrub cover declined from 36 to 6% in the first year post‐fire. Fire reduced the frequencies of three species, A. tridentata ssp. vaseyana, Festuca idahoensis, and Cordylanthus ramosus, of rangeland plants. Frequencies of four plant species, Hesperostipa comata, Polygonum douglasii, Chenopodium fremontii and Chenopodium leptophyllum increased, but only P. douglasii increased for more than a year.Conclusion: This study demonstrates that in an Artemisia tridentata ssp. vaseyana steppe ecosystem without significant non‐native species or anthropogenic disturbances vegetative cover and species composition of the herbaceous community are only minimally altered by fire. The herbaceous component returned to pre‐fire conditions within three years of a fire.
Biodiversity of semi‐arid Mediterranean grasslands: Impact of grazing and afforestation
Authors: Alrababah M.A. , Alhamad M.A. , Suwaileh A. , Al‐Gharaibeh M. 
Published: July 2009

AbstractQuestion: What is the impact of grazing and/or afforestation on grassland diversity, species composition and cover parameters?Location: Semi‐arid Mediterranean grasslands of Jordan.Methods: Vegetation, litter, bare soil and rock cover were compared among four management types – free grazing and protected from grazing with three levels of tree cover. Species composition, plant cover, species richness and evenness were used to evaluate differences in vegetation among management types. Species composition differences among management types were also investigated.Results: Semi‐arid Mediterranean grasslands harbour appreciable levels of plant biodiversity. Grazing did not affect plant diversity, indicating the high resilience against and adaptation to grazing; however,grazing affected species composition and cover parameters. Afforestation seems to protect soil through higher litter cover but its impact on plant biodiversity was negative and markedly affected species composition.Conclusions: Neither protection from grazing or massive afforestation alone are sufficient for conserving biodiversity in this system. A management model is suggested where the landscape should be maintained as a mosaic of four management types: complete protection from grazing, grazing rotation, planting sparse trees in eroded areas and revegetating degraded areas using native, herbaceous and grazing tolerant species.
Vegetation response after restoring the connectivity between a river channel and its floodplain
Authors: Vercoutere B. , Honnay O. , Hermy M. 
Published: July 2009

AbstractQuestions: How is restored inundation affecting the ground‐water composition in a floodplain? To what extent has the floodplain plant community composition changed? What are the effects of flooding frequency and intensity and water quality on the floodplain vegetation changes?Location: Demer river, Flanders, Belgium.Methods: 75 10 m x 10 m plots were surveyed in 1997 and in 2003. Vegetation changes were quantified using a Detrended Correspondence Analysis on the combined 1997–2003 data‐set. Groundwater quality in the floodplain was analysed on macro‐ions. Inundation intensity and frequency were related to vegetation changes.Results: The inundation water was rich in nutrients, although only for NH4 and ortho‐PO4, and a significant increase was recorded in the groundwater. Plant species characteristic of very nutrient‐rich herb vegetation disappeared or decreased while the cover and species richness of species from wet, moderately productive habitats increased. Very few new species colonized the floodplain.Conclusion: Nutrient‐rich flooding water does not necessarily result in increased abundance of species from nutrient‐rich habitats, very likely because N becomes less available by deni‐trification and is transformed into biomass by tall herbs. Either micro‐site limitation or dispersal limitation could explain the colonization problems of new species. The data do not allow distinction between these two mechanisms.
Ground layer heterogeneity and hardwood regeneration in mixed oak forest
Authors: Rinkes Zachary L. , McCarthy Brian C. 
Published: July 2009

AbstractQuestion: What are the effects of small‐scale litter disturbances (simulating large vertebrate scratching and foraging), on Quercus alba, Q. velutina, Fagus grandifolia, and Acer rubrum seedling recruitment?Location: Southeastern Ohio, USA.Methods: Two mixed oak forests containing four experimental management units (burned, thinned, thinned & burned, and un‐manipulated control) were utilized in this study. Silvicutural treatments were applied in the spring of 2001. A small scale disturbance experiment was initiated in the spring of 2002 (Trial 1) and was replicated again in the spring of 2003 (Trial 2). Experimental hardware cloth exclosures, each containing a control (ambient litter) and experimentally scratched (litter removed to bare soil) compartment, were erected in each management unit (N= 8 exclosures per unit).Results:
Acer rubrum, a species that occupies a wide germination niche, produced the most numerous seedlings. Nut‐producing species established more readily in compartments with ambient leaf litter, while A. rubrum was unresponsive to scratching treatment. Units burned (surface leaf litter removed at a broad scale) had the lowest rate of seedling recruitment in Trial 1.Conclusions: These data suggest that an adequate cover of leaf litter is needed to promote optimal recruitment. Control units had the greatest rate of seedling recruitment in Trial 2. The development of a dense understory layer (promoting excessive shading) between Trial 1 and Trial 2 may have affected the recruitment rate in the thinned and thinned & burned units.