991 resultados para Forest Restoration
Resumo:
Despite the wide use of Landscape Character Assessment (LCA) as a tool for landscape planning in NW Europe, there are few examples of its application in the Mediterranean. This paper reports on the results from the development of a typology for LCA in a study area of northern Sardinia, Italy to provide a spatial framework for the analysis of current patterns of cork oak distribution and future restoration of this habitat. Landscape units were derived from a visual interpretation of map data stored within a GIS describing the physical and cultural characteristics of the study area. The units were subsequently grouped into Landscape Types according to the similarity of shared attributes using Two Way Indicator Species Analysis (TWINSPAN). The preliminary results showed that the methodology classified distinct Landscape Types but, based on field observations, there is a need for further refinement of the classification. The distribution and properties of two main cork oak habitats types was examined within the identified Landscape Types namely woodlands and wood pastures using Patch Analyst. The results show very clearly a correspondence between the distribution of cork oak pastures and cork oak woodland and landscape types. This forms the basis of the development of strategies for the maintenance, restoration and recreation of these habitat types within the study area, ultimately for the whole island of Sardinia. Future work is required to improve the landscape characterisation , particularly with respect to cultural factors, and to determine the validity of the landscape spatial framework for the analysis of cork oak distribution as part of a programme of habitat restoration and re-creation.
Resumo:
Question: What is the value of using Rhinanthus minor in grassland restoration and can restrictions on its establishment be overcome? Location: England (United Kingdom). Methods: Two experiments were established to determine the efficacy of inoculating R. minor on a suite of four agriculturally improved grasslands and the efficacy of using R. minor in grassland restoration. In Experiment 1, the effect of herbicide gap creation on the establishment and persistence of R. minor in grasslands ranging in productivity was investigated with respect to sward management. In Exp. 2, R. minor was sown at 1000 seeds/m(2) in conjunction with a standard meadow mix over a randomized plot design into Lolium perenne grassland of moderate productivity. The treatment of scarification was investigated as a treatment to promote R. minor. Results: Gap size had a significant role in the establishment and performance of R. minor, especially the 30 cm diameter gaps (Exp. 1). However, R. minor failed to establish long-term persistent populations in all of the agriculturally improved grasslands. In Exp. 2, establishment of R. minor was increased by scarification and its presence was associated with a significant increase in Shannon diversity and the number of sown and unsown species. Values of grass above-ground biomass were significantly lower in plots sown with R. minor, but values of total above-ground biomass (including R. minor) and forb biomass (not including R. minor) were not affected. Conclusions: The value of introducing R. minor into species-poor grassland to increase diversity has been demonstrated, but successful establishment was dependent on grassland type. The scope for using R. minor in grassland restoration schemes is therefore conditional, although establishment can be enhanced through disturbance such as sward scarification.
Resumo:
Over the last 60 years changes to the management of species-rich mesotrophic grasslands have resulted in the large-scale loss and degradation of this habitat across Europe. Restoration of such grasslands on agriculturally improved pastures provides a potentially valuable approach to the conservation of these threatened areas. Over a four-year period a replicated block design was used to test the effects of seed addition (green hay spreading and brush harvest collection) and soil disturbance on the restoration of phytophagous beetle and plant communities. Patterns of increasing restoration success, particularly where hay spreading and soil disturbance were used in combination, were identified for the phytophagous beetles. In the case of the plants, however, initial differences in restoration success in response to these same treatments were not followed by subsequent temporal changes in plant community similarity to target mesotrophic grassland. It is possible that the long-term consequences of the management treatments would not be the establishment of beetle and plant communities characteristic of the targets for restoration. Restoration management to enhance plant establishment using hay spreading and soil disturbance techniques would, however, still increase community similarity in both taxa to that of species-rich mesotrophic grasslands, and so raise their conservation value.
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We present here an indicator of soil quality that evaluates soil ecosystem services through a set of 5 subindicators, and further combines them into a single general Indicator of Soil Quality (GISQ). We used information derived from 54 properties commonly used to describe the multifaceted aspects of soil quality. The design and calculation of the indicators were based on sequences of multivariate analyses. Subindicators evaluated the physical quality, chemical fertility, organic matter stocks, aggregation and morphology of the upper 5 cm of soil and the biodiversity of soil macrofauna. A GISQ combined the different subindicators providing a global assessment of soil quality. Research was conducted in two hillside regions of Colombia and Nicaragua, with similar types of land use and socio-economic context. However, soil and climatic conditions differed significantly. In Nicaragua, soil quality was assessed at 61 points regularly distributed 200 m apart on a regular grid across the landscape. In Colombia, 8 plots representing different types of land use were arbitrarily chosen in the landscape and intensively sampled. Indicators that were designed in the Nicaragua site were further applied to the Colombian site to test for their applicability. In Nicaragua, coffee plantations, fallows, pastures and forest had the highest values of GISQ (1.00; 0.80; 0.78 and 0.77, respectively) while maize crops and eroded soils (0.19 and 0.10) had the lowest values. Examination of subindicator values allowed the separate evaluation of different aspects of soil quality: subindicators of organic matter, aggregation and morphology and biodiversity of macrofauna had the maximum values in coffee plantations (0.89; 0.72 and 0.56, respectively on average) while eroded soils had the lowest values for these indicators (0.10; 0.31 and 0.33, respectively). Indicator formulae derived from information gained at the Nicaraguan sites were not applicable to the Colombian situation and site-specific constants were calculated. This indicator allows the evaluation of soil quality and facilitates the identification of problem areas through the individual values of each subindicator. It allows monitoring of change through time and can guide the implementation of soil restoration technologies. Although GISQ formulae computed on a set of data were only valid at a regional scale, the methodology used to create these indices can be applied everywhere.
Resumo:
Leaves of 14 species of Ficus growing in the Budongo Forest, Uganda, were analysed for vacuolar flavonoids. Three to six accessions were studied for each species to see whether there was intraspecific chemical variation. Thirty-nine phenolic compounds were identified or characterised, including 14 flavonol O-glycosides, six flavone O-glycosides and 15 flavone C-glycosides. In some species the flavonoid glycosides were acylated. Ficus thonningii contained in addition four stilbenes including glycosides. Most of the species could be distinguished from each other on the basis of their flavonoid profiles, apart from Ficus sansibarica and Ficus saussureana, which showed a very strong intraspecific variation. However, on the whole flavonoid profiles were sufficiently distinct to help in future identifications.
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The availability of a network strongly depends on the frequency of service outages and the recovery time for each outage. The loss of network resources includes complete or partial failure of hardware and software components, power outages, scheduled maintenance such as software and hardware, operational errors such as configuration errors and acts of nature such as floods, tornadoes and earthquakes. This paper proposes a practical approach to the enhancement of QoS routing by means of providing alternative or repair paths in the event of a breakage of a working path. The proposed scheme guarantees that every Protected Node (PN) is connected to a multi-repair path such that no further failure or breakage of single or double repair paths can cause any simultaneous loss of connectivity between an ingress node and an egress node. Links to be protected in an MPLS network are predefined and an LSP request involves the establishment of a working path. The use of multi-protection paths permits the formation of numerous protection paths allowing greater flexibility. Our analysis will examine several methods including single, double and multi-repair routes and the prioritization of signals along the protected paths to improve the Quality of Service (QoS), throughput, reduce the cost of the protection path placement, delay, congestion and collision.
Resumo:
As Terabyte datasets become the norm, the focus has shifted away from our ability to produce and store ever larger amounts of data, onto its utilization. It is becoming increasingly difficult to gain meaningful insights into the data produced. Also many forms of the data we are currently producing cannot easily fit into traditional visualization methods. This paper presents a new and novel visualization technique based on the concept of a Data Forest. Our Data Forest has been designed to be used with vir tual reality (VR) as its presentation method. VR is a natural medium for investigating large datasets. Our approach can easily be adapted to be used in a variety of different ways, from a stand alone single user environment to large multi-user collaborative environments. A test application is presented using multi-dimensional data to demonstrate the concepts involved.
Resumo:
As we increase our ability to produce and store ever larger amounts of data, it is becoming increasingly difficult to understand what the data is trying to tell us. Not all the data we are currently producing can easily fit into traditional visualization methods. This paper presents a new and novel visualization technique based on the concept of a Data Forest. Our Data Forest has been developed to be utilised by virtual reality (VR) systems. VR is a natural information medium. This approach can easily be adapted to be used in collaborative environments. A test application has been developed to demonstrate the concepts involved and a collaborative version tested.
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This paper considers the contribution of pollen analysis to conservation strategies aimed at restoring planted ancient woodland. Pollen and charcoal data are presented from organic deposits located adjacent to the Wentwood, a large planted ancient woodland in southeast Wales. Knowledge of the ecosystems preceding conifer planting can assist in restoring ancient woodlands by placing fragmented surviving ancient woodland habitats in a broader ecological, historical and cultural context. These habitats derive largely from secondary woodland that regenerated in the 3rd–5th centuries A.D. following largescale clearance of Quercus-Corylus woodland during the Romano-British period. Woodland regeneration favoured Fraxinus and Betula. Wood pasture and common land dominated the Wentwood during the medieval period until the enclosures of the 17th century. Surviving ancient woodland habitats contain an important Fagus component that probably reflects an earlier phase of planting preceding conifer planting in the 1880s. It is recommended that restoration measures should not aim to recreate static landscapes or woodland that existed under natural conditions. Very few habitats within the Wentwood can be considered wholly natural because of the long history of human impact. In these circumstances, restoration should focus on restoring those elements of the cultural landscape that are of most benefit to a range of flora and fauna, whilst taking into account factors that present significant issues for future conservation management, such as the adverse effects from projected climate change.
Resumo:
This paper presents a unique two-stage image restoration framework especially for further application of a novel rectangular poor-pixels detector, which, with properties of miniature size, light weight and low power consumption, has great value in the micro vision system. To meet the demand of fast processing, only a few measured images shifted up to subpixel level are needed to join the fusion operation, fewer than those required in traditional approaches. By maximum likelihood estimation with a least squares method, a preliminary restored image is linearly interpolated. After noise removal via Canny operator based level set evolution, the final high-quality restored image is achieved. Experimental results demonstrate effectiveness of the proposed framework. It is a sensible step towards subsequent image understanding and object identification.
Resumo:
1. Declines in area and quality of species-rich mesotrophic and calcareous grasslands have occurred all across Europe.While the European Union has promoted schemes to restore these grasslands, the emphasis for management has remained largely focused on plants. Here we focus on restoration of the phytophagous beetles of these grasslands. Although local management, particularly that which promotes the establishment of host plants, is key to restoration success, dispersal limitation is also likely to be an important limiting factor during the restoration of phytophagous beetle assemblages. 2. Using a 3-year multi-site experiment, we investigated how restoration success of phytophagous beetles was affected by hay-spreading management (intended to introduce target plant species), success in restoration of the plant communities and the landscape context within which restoration was attempted. 3. Restoration success of the plants was greatest where green hay spreading had been used to introduce seeds into restoration sites. Beetle restoration success increased over time, although hayspreading had no direct effect. However, restoration success of the beetles was positively correlated with restoration success of the plants. 4. Overall restoration success of the phytophagous beetles was positively correlated with the proportion of species-rich grassland in the landscape, as was the restoration success of the polyphagous beetles. Restoration success for beetles capable of flight and those showing oligophagous host plant specialism were also positively correlated with connectivity to species-rich grasslands. There was no indication that beetles not capable of flight showed greater dependence on landscape scale factors than flying species. 5. Synthesis and applications. Increasing the similarity of the plant community at restoration sites to target species-rich grasslands will promote restoration success for the phytophagous beetles. However, landscape context is also important, with restoration being approximately twice as successful in those landscapes containing high as opposed to low proportions of species-rich grassland. By targeting grassland restoration within landscapes containing high proportions of species-rich grassland, dispersal limitation problems associated with restoration for invertebrate assemblages are more likely to be overcome.
Resumo:
This study focuses on the restoration of chalk grasslands over a 6-year period and tests the efficacy of two management practices, hay spreading and soil disturbance, in promoting this process for phytophagous beetles. Restoration success for the beetles, measured as similarity to target species-rich chalk grassland, was not found to be influenced by either management practice. In contrast, restoration success for the plants did increase in response to hay spreading management. Although the presence of suitable host plants was considered to dictate the earliest point at which phytophagous beetles could successfully colonized, few beetle species colonized as soon as their host plants became established. Morphological characteristics and feeding habits of 27 phytophagous beetle species were therefore tested to identify factors that limited their colonization and persistence. The lag time between host plant establishment and colonization was greatest for flightless beetles. Beetles with foliage-feeding larvae both colonized at slower rates than seed-, stem-, or root-feeding species and persisted within the swards for shorter periods. Although the use of hay spreading may benefit plant communities during chalk grassland restoration, it did not directly benefit phytophagous beetles. Without techniques for overcoming colonization limitation for invertebrate taxa, short-term success of restoration may be limited to the plants only.