1,720,986 research outputs found
Automatische Detektion des Rapsanbaus aus dem Weltraum:Anwendung von neuen Algorithmen zur automatischen Identi kation von landwirtschaftlichen Anbau 0chen mit multispektralen Satellitendaten am Beispiel von Raps
No full textThe dispersal of new genes resulting from the cultivation of genetically modified plants holds risks that are difficult to assess. In this context the situation of cultivation is of particular interest since fields are potential sources of the transfer of new genes to non-modified or related plants. The aim of this work is the identification of canola cultivation areas in northern Germany in the studied period from 1995 to 2002. The sizes of the fields and the investigation area pose requirements on the satellite data best met the LANDSAT Thematic Mapper and Enhanced Thematic Mapper and the Indian Remote Sensing Satellite Linear Imaging Scanning Spectrometer/3.The first processing step, the georectification is done by a passpoint correlation which is improved by an additional correction step, based on the correlation of image clips.The next processing step is the identification of clouds and their shadows. Opaque clouds can be identified by their brightness and low top temperature. Thin clouds are identified based on the Haze Optimized Transform method. The third processing step, the classification, is performed by the Mahalanobis Distance Clasifier (MDC) because it only requires training data for one single surface type. The accuracy of the MDC is enhanced by a segmentation of the MDC result used to identify single wrongly identified pixels and to perform region growing to include pixels missed by the MDC.The results are approximated by rectangles of equal orientation and area which allows a simple evaluation of the field distances and other parameters of interest. The results are used to produce statistics to investigate these parameters for the cultivation of canola in northern Germany. The results of the classification are compared to validation data, i.e., edges and positions of known canola fields and agricultural statistics for 1995 and 1999. This validation showed that the total acreage of canola is identified with 70 to 90% accuracy
Eine Untersuchung der Waldökosystem-Gesundheit inBezug auf eine Anthropogenetische Störung in der südwestlichen Mau Waldreserve, Kenia
No full textThe dissertation describes investigations carried out from September 2005 to August 2006 to assess forest ecosystem health in relation to human disturbance in the South-western Mau forest reserve Kenya. The study involved the determination and comparison of tree species composition and structure, regeneration potential and capacity, litter production and nutrient fluxes between disturbed and undisturbed sites. A socioeconomic appraisal of the inhabitants was also carried out. Forest cover change analysis of the greater Mau forest was done for the period between 1984 and 2003 using Landsat satellite images. A total of 24 families, 34 genera and 37 woody species comprising mainly trees were enumerated. There were 20 families in the undisturbed sites while 21 were present in the disturbed sites. In undisturbed sites, 30 species belonging to 29 genera were recorded while 29 species from 27 genera were tallied in the disturbed sites. The mean species richness was higher in the disturbed sites. Undisturbed sites had a lower proportion of shrubs and under storey trees with a higher frequency of over storey trees. Both sites had high number of seedlings and wildings. Regarding survival and recruitment from seasonal seed rain, disturbed sites had significantly higher mean species richness. Germinations from seasonal seed rain indicated higher mean seedling species richness in disturbed plots while seedling density was significantly higher in undisturbed plots. No significant mean differences in species composition were recorded from the seed bank trials. A higher amount of fine litter was collected in disturbed plots with insignificant mean differences with regard to K, C and N content between the sites. There were no significant mean differences in the C: P, ratios whereas undisturbed plots had significantly lower mean C: N ratios. Within stand mean nutrient use efficiency for C, N, P, K, and Ca were lower in the undisturbed plots.Survey results indicated that several tree species that were once common or dominant in the area were increasingly becoming rare. Increase in human population, firewood collection, agricultural expansion, land subdivision among others were ranked as important causes of forest degradation. Positive significant correlations were reported between the definition of provision of services, forest condition, provision of goods, the adequacy of goods provided and ecosystem health. However, a significant negative correlation was reported for the values attached to the current land use. The presence of disturbance indicator species like Neoboutonia macrocalyx, Croton megalocarpus and Vernonia auriculifera in the vegetation community indicates considerable levels of human disturbance in the reserve representing retrogression in the vegetation succession. The vertical stratification of the forest reserve depicts secondary growth in the reserve. The potential for natural regeneration of trees after natural or anthropogenic disturbance exists despite a poor soil seed bank. High litter annual turn over in disturbed sites, coupled with lower nutrient content and nutrient use efficiency as well as higher fine litter C: N and C: P ratios defines them as poorer sites. A chronological degradation in the condition of the forest over time is apparent with current land uses having negative significant effects. Thematic change and image difference analysis indicated a significant change in closed canopy forest
Systemic Risks of Genetically Modified Organisms in Crop Production: Interdisciplinary Perspective
No full textThe GeneRisk research consortium analysed the implications of the cultivation of genetically modified organisms (GMO). The risks involved transcend the borders of very different systems. Therefore, they need to be analysed using interdisciplinary and transdisciplinary approaches. One central scientific issue was the assessment of the spatial implications of GMO cultivation for areas of large extent, examining Bt-maize as the currently most relevant GM crop and oilseed rape as an additional example
Fortschreibung des Konzeptes zur Bewertung von Risiken bei Freisetzungen und dem Inverkehrbringen von gentechnisch veränderten Organismen
No full textSystemic Risks of Genetically Modified Organisms in Crop Production: Interdisciplinary Perspective
No full textThe GeneRisk research consortium analysed the implications of the cultivation of genetically modified organisms (GMO). The risks involved transcend the borders of very different systems. Therefore, they need to be analysed using interdisciplinary and transdisciplinary approaches. One central scientific issue was the assessment of the spatial implications of GMO cultivation for areas of large extent, examining Bt-maize as the currently most relevant GM crop and oilseed rape as an additional example
GM-Crop Cultivation - Ecological Effects on a Landscape Scale Proceedings of the Third GMLS Conference 2012 in Bremen
No full textAfter two successful meetings on the ecological implications of GM-crop cultivation in 2008 and 2010, the authors felt encouraged to carry out a follow-up conference in 2012. GMLS III highlights recent scientific developments in the analysis of risks in the agricultural use of genetically modified plants. While in some countries a GM-based agriculture has been largely established, other regions of the world continue cultivation of conventional varieties only. This acknowledges a persistent reservation of the public towards GMO products. The overall need of an emphasis in independent studies becomes continuously more obvious. Experts from Europe, United States, Ghana and Argentina report their scientific results and experience with ecological, socio-economical and administrative implication
Risk hazard damage
No full textIn der aktuellen Diskussion um Risiken der Agro-Gentechnik werden mögliche Gefahren für die Biologische Vielfalt noch zu wenig beachtet. Für die Einschätzung der Nutzung von gentechnisch veränderten Organismen sind standardisierte Bewertungsgrundlagen und eine einheitliche Definition des Begriffs "Ökologischer Schaden" notwendig. Hierzu werden im vorliegenden Werk Anregungen aus internationaler Sicht gegeben. In die Beiträge sind Ergebnisse aus unterschiedlichen Forschungsrichtungen - z.B. der Risikoforschung und der Ethik - eingeflossen. Die Zusammenstellung der 20 Beiträge soll eine Grundlage für die Erarbeitung von Bewertungskriterien für gentechnisch veränderte Organismen aus Naturschutzsicht liefern
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