• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 104
  • 36
  • 13
  • 10
  • 4
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 199
  • 199
  • 53
  • 39
  • 35
  • 31
  • 29
  • 25
  • 24
  • 23
  • 22
  • 21
  • 20
  • 20
  • 20
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Plynose kirtavietėse paliekamų biologinės įvairovės medžių būklės ir išlikimo analizė / Survival and Status Analysis of biodiversity trees left in the clean-cut

Morkūnas, Vilius 14 January 2009 (has links)
Magistro darbe tiriama paliktų biologinei įvairovei medžių plyno kirtimo biržėse būklė ir išlikimas. Darbo objektas – plyno kirtimo biržės ir jose palikti biologinės įvairovės medžiai. Darbo tikslas – nustatyti plynose kirtavietėse paliekamų biologinės įvairovės medžių būklę, rūšinę sudėtį, kiekį ir pasiskirstymą bei išlikimą kirtavietėje. Darbo metodika – atliekant tyrimą, dėmesys buvo kreipiamas į du skirtingus parametrus. Pirmiausia buvo išsiaiškintas atskirų medžių atsparumas aplinkos poveikiams, priklausomai nuo jų individualių savybių. Kitas tyrimas, kuriame buvo apskaičiuota žuvusių medžių dalis kirtavietėje, priklausomai nuo kirtavietės parametrų ir medžių išsidėstymo joje. Darbo rezultatai – Plynose kirtavietėse vidutiniškai paliekama 11 medžių hektare, iš kurių per pirmuosius šešerius metus 14 procentų žūsta. Didėjant kirtavietės dydžiui bendras išlikimo procentas mažėja. Geriau išlieka grupėmis paliekami medžiai nei medžiai paliekami pavieniui. Didelę reikšmę medžių išlikimui turi vėjas - du trečdaliai žuvusių medžių žuvo dėl vėjo, buvo išversti arba nulaužti. Didžiausią poveikį vėjas turi medžiams, kurių paviršinė šaknų sistema, ir medžiams, kurių storio ir aukščio santykis mažesnis. Didėjant atstumui nuo kirtavietės krašto, dėl didesnio vėjo poveikio, medžių išlikimas mažėja. Atskirų medžių rūšių išlikimas priklauso nuo augavietės atitikimo medžių rūšiai ir paliekamų medžių individualių parametrų. Atrenkant paliekamus biologinei įvairovei medžius didesnis... [toliau žr. visą tekstą] / The master thesis presents evaluation of the trees condition and ability to survive, which are left for biological diversity in the clear cutting areas. Object of the work – trees left for biological diversity in clear cutting areas Aim of the work – to evaluate the condition, variety, quantity and layout of the trees, left for biological diversity in clear cutting areas. Methods of work- attention were paid to two different indicates: first, it has been investigated trees ability to resist environmental factors, depending on individual aspects of each tree. Second, it has been investigated area of coppice, where it was examined fraction of dead trees depending of trees layout and different factors in the coppice. Result of the work – there are approximately eleven trees left in each hectare and 14 percent of them do not survive during the first 6 years. The more the coppice expands the less possibility of tree to survive. The trees are more likely to survive when they are left in groups rather than on their own. The wind has important implication to the trees; two thirds of the trees get destroyed by the wind. The trees that are mostly in danger due to the wind are the ones that have roots spread out close to the ground surface and which have a reduced diameter and height ratio. Trees that are in the middle of the coppice have an increased risk to die from wind. Various trees survive depending on the type of the tree specification and its environmental... [to full text]
72

Benefit sharing in accordance with the Convention on Biological Diversity / by P. Steenkamp

Steenkamp, Philip January 2006 (has links)
The Convention on Biological Diversity (CBD) significantly enhanced the scope and potential effectiveness of the international legal regime for the conservation of biological diversity world wide together with the sustainable use of its components. It goes beyond the conservation of biological conservation per se and comprehends such diverse issues as sustainable use of biological resources, access to genetic resources, the sharing of benefits derived from the use of genetic material and technology, including biotechnology. The CBD has three objectives, which are the conservation of biological diversity, secondly the sustainable use of its components and thirdly the fair and equitable sharing of benefits arising out of the utilisation of genetic resources. The third objective includes the sharing of benefits by means of appropriate access to genetic resources and by appropriate transfer of relevant technologies, taking into account all rights over such resources and technologies as well as appropriate funding. As part of the process of achieving these goals, the CBD establishes a new international framework for access to genetic resources and the sharing of benefits from their use. In addition to its conservation measures, the CBD is also an economic treaty in the sense that it develops and regulates the ongoing exchange of genetic resources and, in particular, the emerging trade in biotechnology. During the negotiations of the CBD the concept of the trade in biotechnology dominated much of the discussions surrounding the Convention. This was the cause of deep differences between the technologically rich north and the biodiversity rich south. It was and still is apparent that developed countries, or corporate companies in these countries, exploit natural recourses only found in developing countries, without sharing the resulting proceeds. It is shown that uneven distribution of natural, technological and economic resources occur in relationships between the northern hemisphere and its southern counterpart. It is a well-known fact that the northern hemisphere is financially and technologically superior to its southern counterpart. Intellectual property rights ("IPR"), with specific reference to patent law, enables developed countries andlor companies in those countries to exploit this economic discrepancy. Developed countries accordingly acquire biological recourses and exploit them with resulting benefits thereby circumventing the sharing of such benefits through IPR systems. Benefits are thereby withheld from developing countries that provide such genetic recourses. The author will mainly focus on the question that arises as to how the CBD addresses benefit sharing in the light of the differences between the northern developed- and southern developing countries. South Africa will be studied as an example of a developing country that incorporated the provisions of the CBD in its national legislation as it promulgated the National Environmental Management: Biodiversity Act (BDA), which embodies the guidelines and principles for bioprospecting and benefit sharing, captured in the CBD and the Cartagena Protocol. The provisions contained in the BDA will be used as a practical example of the application of the CBD in the municipal law of developing countries. / Thesis (LL.M. (Import and Export Law))--North-West University, Potchefstroom Campus, 2007.
73

Paliktų biologinei įvairovei medžių Prienų miškų urėdijos plyno kirtimo biržėse vertinimas / Evaluation of the Trees Left for Biological Diversity in Clear Cutting in Prienai Forestry region

Žiobaitė, Dalia 16 August 2007 (has links)
Magistro darbe tiriama paliktų biologinei įvairovei medžių Prienų miškų urėdijoje plyno kirtimo biržėse būklė. Darbo objektas – Prienų miškų urėdijos plyno kirtimo birž��s ir jose biologinei įvairovei palikti medžiai. Darbo tikslas – Įvertinti 2002-2006 matų laikotarpyje biologinei įvairovei paliktų medžių Prienų miškų urėdijos plyno kirtimo biržėse būklę. Darbo metodika – surinkta informacija apie Prienų miškų urėdijoje plynų kirtimų biržes ir jose biologinei įvairovei paliktus medžius. Iš kiekvienų 2002 – 2006 metais plynais kirtimais kirstų biržių buvo pasirinkta po 10 biržių. Pasirinktose plyno kirtimo biržėse buvo įvertinti biologinei įvairovei paliktų medžių būklė pagal šiuos rodiklius: medžių būklė, lajos defoliacija ir medžių pažeidimai. Darbo rezultatai – Nuo 2002 iki 2006 metų vidutinis paliktų medžių skaičius plyno kirtimo biržėse viename hektare išaugo 1,5 karto, bet jų vidutinis skersmuo sumažėjo. Vadinasi su kiekvienais metais buvo paliekama vis daugiau, bet smulkesnių medžių. Medžių lajų vertinimo duomenimis, medžių būklė yra nepatenkinama, o to priežastis gali būti staigus pavienių medžių augusių medyne atidengimas, dėl ko neprisiteikę augti atviroje vietoje medžiai nusilpo. Tyrimo metu nustatyta, kad apie ketvirtadalį medžių iš biologinei įvairovei paliktų medžių galima vertinti, kaip potencialų negyvos medienos šaltinį plynose biržėse. Artimoje ateityje šie medžiai pasitarnaus daugeliui miško ekosistemos organizmų egzistavimui. / The master thesis presents evaluation of the condition of the trees, left fot biological diversity in clear cutting areas of Prienai forestry region. Object of the work – trees left for biological diversity in clear cutting areas of Prienai forestry region. Aim of the work – to evaluate the condition of the trees, left fot biological diversity in clear cutting areas of Prienai forestry region in the period of 2002-2006. Methods of the work – 10 clear cutting areas from each of smooth wood areas, felt in Prienai forestry region of the period of 2002-2006, were selected for investigation. Each of the left trees was estimated according to the following indicates: condition of trees, crow defoliation and injuries of trees Results of the work – In 2002-2006 period mean number of trees decreased, but mean diameter of trees increased. Almost ¼ of trees died in offer the first year. Left trees for biological diversity had higher defoliation of crowns.
74

Paliktų biologinei įvairovei medžių Šilutės miškų urėdijoje plyno kirtimo biržėse vertinimas / Evaluation of the Trees Left for Biological Diversity in Clear Cutting in Šilutė Forestry region

Valančius, Jonas 14 January 2009 (has links)
Magistro darbe tiriama paliktų biologinei įvairovei medžių Šilutės miškų urėdijoje plyno kirtimo biržėse būklė. Darbo objektas- Šilutės miškų urėdijos plyno kirtimo biržėse palikti biologinei įvairovei medžiai. Darbo tikslas- ištirti 2003- 2007 metų laikotarpyje biologinei įvairovei paliktų medžių Šilutės miškų urėdijos plyno kirtimo biržėse būklę. Darbo metodika- surinkti informaciją apie Šilutės miškų urėdijoje plynų kirtimų biržėse ir jose biologinei įvairovei paliktus medžius. Iš kiekvienų 2003-2007 metais plynais kirtimais kirstų biržių buvo pasirinkta 10 biržių. Pasirinktose plyno kirtimo biržėse buvo įvertinti biologinei įvairovei paliktų medžių būklė pagal šiuos rodiklius: medžių būklė, lajos defoliacija, medžių pažeidimai, medžių skersmuo. Darbo rezultatai- nuo 2003 iki 2007 metų vidutinis paliktų medžių skaičius plyno kirtimo biržėse viename hektare padidėjo, o skersmenys skirtingi. Kiekvienais metais buvo paliekama vis daugiau medžių. Medžių lajų vertinimo duomenimis, medžių būklė yra nepatenkinama, o to priežastis gali būti staigus pavienių medžių augusių medyne atidengimas, dėl ko neprisitaikę augti atviroje vietoje medžiai nusilpo. Tyrimo metu nustatyta, kad apie ketvirtadalį medžių iš biologinei įvairovei paliktų medžių galima vertinti, kaip potencialų negyvos medienos šaltinį plynose biržėse. Ateityje šie medžiai pasitarnaus daugeliui miško ekosistemos organizmų egzistavimui. / Biodiversity is the variation of life forms within a given ecosystem, biome or for the entire Earth. The object of this research is the condition of trees left for biodiversity in the birch‘s open fields of Šilute‘s forest district. The aim of the paper was the following: to prepare the methodology and state the object; to make the research of the condition of trees left for biodiversity; to analize the condition of those tress according to thier diametre. The objekto f this research is the condition of tress in open field of Šilute‘s forest district which were left for biodiversity.
75

Benefit sharing in accordance with the Convention on Biological Diversity / by P. Steenkamp

Steenkamp, Philip January 2006 (has links)
The Convention on Biological Diversity (CBD) significantly enhanced the scope and potential effectiveness of the international legal regime for the conservation of biological diversity world wide together with the sustainable use of its components. It goes beyond the conservation of biological conservation per se and comprehends such diverse issues as sustainable use of biological resources, access to genetic resources, the sharing of benefits derived from the use of genetic material and technology, including biotechnology. The CBD has three objectives, which are the conservation of biological diversity, secondly the sustainable use of its components and thirdly the fair and equitable sharing of benefits arising out of the utilisation of genetic resources. The third objective includes the sharing of benefits by means of appropriate access to genetic resources and by appropriate transfer of relevant technologies, taking into account all rights over such resources and technologies as well as appropriate funding. As part of the process of achieving these goals, the CBD establishes a new international framework for access to genetic resources and the sharing of benefits from their use. In addition to its conservation measures, the CBD is also an economic treaty in the sense that it develops and regulates the ongoing exchange of genetic resources and, in particular, the emerging trade in biotechnology. During the negotiations of the CBD the concept of the trade in biotechnology dominated much of the discussions surrounding the Convention. This was the cause of deep differences between the technologically rich north and the biodiversity rich south. It was and still is apparent that developed countries, or corporate companies in these countries, exploit natural recourses only found in developing countries, without sharing the resulting proceeds. It is shown that uneven distribution of natural, technological and economic resources occur in relationships between the northern hemisphere and its southern counterpart. It is a well-known fact that the northern hemisphere is financially and technologically superior to its southern counterpart. Intellectual property rights ("IPR"), with specific reference to patent law, enables developed countries andlor companies in those countries to exploit this economic discrepancy. Developed countries accordingly acquire biological recourses and exploit them with resulting benefits thereby circumventing the sharing of such benefits through IPR systems. Benefits are thereby withheld from developing countries that provide such genetic recourses. The author will mainly focus on the question that arises as to how the CBD addresses benefit sharing in the light of the differences between the northern developed- and southern developing countries. South Africa will be studied as an example of a developing country that incorporated the provisions of the CBD in its national legislation as it promulgated the National Environmental Management: Biodiversity Act (BDA), which embodies the guidelines and principles for bioprospecting and benefit sharing, captured in the CBD and the Cartagena Protocol. The provisions contained in the BDA will be used as a practical example of the application of the CBD in the municipal law of developing countries. / Thesis (LL.M. (Import and Export Law))--North-West University, Potchefstroom Campus, 2007.
76

Regional biodiversity management strategy : case study on the Flinders Ranges

Dorjgurhem, Batbold. January 1999 (has links) (PDF)
Bibliography: leaves 107-117. This thesis examines the rationale for managing biological diversity on a regional basis and develops recommendations for the use of two computational methods in biodiversity management planning by conducting a case study in the Flinders Ranges, centred on the Yellow-footed Rock Wallaby (abstract)
77

Marine benthic biodiversity-ecosystem function relations in complex systems

Godbold, Jasmin Annica January 2008 (has links)
A wealth of empirical and theoretical studies has investigated the consequences of biodiversity loss on ecosystem properties. Whilst the importance of biodiversity in mediating ecosystem properties has been established, the magnitude and direction of effects vary between studies and are dependent on the biotic and abiotic conditions of the experimental system. Consequently there are still significant gaps in our understanding of how species loss may affect ecosystem properties, what the underlying mechanisms are, and how the effects of species loss are modified by environmental context.
78

Diversidade de anfibios da floresta com Araucária

Conte, Carlos Eduardo [UNESP] 26 February 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:30:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-26Bitstream added on 2014-06-13T18:41:07Z : No. of bitstreams: 1 conte_ce_dr_sjrp.pdf: 1860470 bytes, checksum: 972bc0065c56666559ef1bc683289662 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O primeiro passo para a conservação de anfíbios de uma determinada área é promover o conhecimento sobre a composição e a distribuição das espécies. O rápido declínio nas populações de várias espécies de anuros ao redor do mundo ressalta a necessidade e urgência no conhecimento da anurofauna, especialmente em regiões pouco amostradas, caso da Floresta com Araucária (FOM). Os objetivos do presente estudo foram: sintetizar o conhecimento sobre a diversidade de anfíbios registrados na FOM do sul do Brasil; aumentar o conhecimento sobre a distribuição geográfica de algumas espécies; inventariar e comparar a diversidade de anuros, nas fases larval e adulta, em habitats florestais e campos associados em dois estágios distintos de conservação (preservado e alterado); detectar possíveis variações sazonais no período reprodutivo das espécies; e comparar a composição de espécies de FOM com três ecossistemas adjacentes. Um total de 129 espécies foi levantado, sendo 103 registradas nas áreas amostras e o restante em registros secundários de museus. Dessas, 13 espécies são endêmicas da FOM. Por meio de comparações morfológicas e do canto de anúncio, 18 espécies foram confirmadas como não descritas. Além disso, pôde-se ampliar significativamente o conhecimento da distribuição geográfica de oito espécies de anfíbios anuros: Ischnocnema henselii, Dendropsophus anceps, D. nahdereri, Scinax granulatus, Trachycephalus dibernardoi, Pseudis cardosoi, Leptodactylus araucaria e L. nanus. Alguns destes registros representam avanços nas análises taxonômicas para FOM, por exemplo: Ischnocnema henselii é uma espécie críptica e algumas populações até o momento eram confundidas no Paraná com I. guentheri; Trachycephalus dibernardoi era identificada como T. imitatrix e Leptodactylus nanus como L. marmoratus. Na comparação entre os habitats inseridos... / The first step in amphibian conservation of an area is to improve the knowledge about the species composition and distribution. The fast decrease in several anurans species worldwide highlights the urgency of knowledge about this faunal group, meanly in less studied regions, like the Brazilian Araucaria forest. Our aim is to synthesize the knowledge about the amphibian diversity recorded on Araucaria forest in Southern Brazil; to improve the knowledge about the geographic distribution of anurans species; to survey and compare the diversity of adults and tadpoles between preserved and disturbed forests and associated “campos” habitats (natural associated open areas recovered by herbaceous plants); to check for seasonal variations in the species reproductive periods; and to compare the Araucaria forest anuran species composition with other three adjacent ecosystems. We found records of 129 species occurring in Araucaria forest ecosystem, with 103 registered during the field survey and the remaining registered consulting specimens of scientific collections. A total of 13 species are endemic to this ecosystem. Comparisons of morphology and bioacoustics confirmed that 18 species, registered during field research, are not described yet. Moreover, we improved the knowledge on geographical distribution of eight species: Ischnocnema henselii, Dendropsophus anceps, D. nahdereri, Scinax granulatus, Trachycephalus dibernardoi, Pseudis cardosoi, Leptodactylus araucaria e L. nanus. Some of this records represent advances on taxonomic identification, for exemple: Ischnocnema henseli is a cryptic species and some of its populations were so far confused with I. guentheri in Paraná state; we also found that Trachycephalus dibernardoi was misidentified as T. imitatrix and Leptodactylus nanus as L. marmoratus. Comparing the preserved and disturbed forest remnants, we found differences... (Complete abstract click electronic access below)
79

Biodiversity measurement, species interactions and sustainability

Gerber, Nicolas, Economics, Australian School of Business, UNSW January 2006 (has links)
Throughout the last two decades, biodiversity has been increasingly acknowledged as a valuable asset. However there are numerous challenges to managing the asset. Firstly, there is no universally accepted measure of biodiversity per se. As a consequence, rather than measuring the intrinsic value of biodiversity the focus has typically shifted to valuing biodiversity services. Secondly, biodiversity issues should not be considered in a vacuum, but rather alongside general natural resource management problems. Conservation agencies and regulators alike would greatly benefit from more transparent biodiversity targets for conservation policies and natural resource management. This thesis makes a number of contributions to meet these challenges including measuring biodiversity, modelling diverse ecosystems and considering biodiversity outcomes in the management of an environmental resource. To value biodiversity, it is essential to measure it. Focusing on pairwise genetic dissimilarities at the species level, this thesis develops two models for measuring biodiversity. An axiomatic diagnosis of the existing and new measures is presented. This comparison suggests that the adequate biodiversity measure depends on the context. The diversity measures describe the biodiversity catalogue available at a given point in time. Modelling biodiversity is important for forecasting the impact of conservation decisions and understanding the future value of biodiversity. The importance of each species, however, depends on its role in the ecosystem as well as its genetic diversity. The interactions between species are therefore investigated and described, using a new model built around CES production functions. Three existing models based on predator-prey equations are extended to the multi-species case. These interaction models provide the necessary link for biodiversity maintenance over time. The four models are compared using simulations and an axiomatic approach. This approach shows that the new model performs well, offers the flexibility required to describe different types of ecosystems and is less data intensive. Finally, a case study of natural resource exploitation is presented, illustrating the idea that biodiversity loss can have direct economic implications in natural resource management. The model shows the impact of market structures on the extraction path of the resource and the distribution of the resource rent.
80

Fire frequencies for Western Sydney's woodlands : indications from vegetation dynamics

Watson, Penelope J., University of Western Sydney, College of Health and Science, School of Natural Sciences January 2005 (has links)
Although the importance of fire management for biodiversity conservation is increasingly being recognised, little is known about the relationship between fire regimes and plant diversity in Australia’s temperate grassy woodland ecosystems. This project sought to address this gap in the woodlands of Western Sydney’s Cumberland Plain. Aspects of vegetation dynamics were investigated through six studies, mostly in shale-based Cumberland Plain Woodland (CPW) remnants. Results indicate that fire frequency profoundly affects both vegetation composition and structure. The influence of fire cycles was most readily apparent in the shrub layer. Findings from the six studies were synthesized into a state and transition model which allows exploration of management actions. Interfire intervals between 4 and 12 years are predicted to maintain Themeda woodland with both Bursaria thickets and open areas, and obligate seeder shrubs. Variable intervals across time and space within these thresholds should maintain much of the landscape at fuel levels compatible with property protection; fuel loads in CPW peak well below those in woodlands on sandstone. Low fire frequency remnants dominated by Bursaria retain many conservation values, but are likely to support lower abundances of obligate seeder shrubs and open patch herbs, and to be more weed-prone, than remnants burnt once or twice a decade. Experimentation with one or two short interfire intervals may be appropriate in long unburnt CPW. / Doctor of Philosophy (PhD)

Page generated in 0.1151 seconds