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  • 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.
51

Rescaling conflictive access and property relations in the context of REDD+ in Jambi, Indonesia

Hein, Jonas Ibrahim 15 April 2016 (has links)
No description available.
52

Modelling socio-economic effects of implementing reduced-impact logging : a case study of Berau District East Kalimantan Province Indonesia.

Martana, Kadim January 2013 (has links)
Reduced-impact logging (RIL) was identified as a measure, complementary to other identified measures, which can contribute to Indonesia reducing emissions from forestry and forest degradation (REDD+). In this light, the research was aimed to investigate the economy-wide impact of implementing RIL on the economy, which was studied at the district level. For this purpose, an expert opinion survey method was integrated with Berau computable general equilibrium (CGE) model. The expert opinion survey was utilised to: (i) generate information and confirm the impact of implementing RIL on logging costs, and (ii) obtain an estimate of the incentive required by logging companies to maintain the practice of RIL. Results of this approach provided input to the Berau CGE model. In addition, multiple ways of data gathering were employed to develop the dataset required for the general equilibrium analysis. Simulation results suggest that the economic impact of implementing RIL policy is negative but small on the Berau economy compared to a situation where the RIL is not implemented. Worker households (particularly agricultural worker households) are worse off and non-agricultural households are better off. Furthermore, providing compensation, which was simulated as a logging output- based subsidy, can improve the Berau economy, although to only a lesser degree. The RIL policy causes a significant negative impact on logging output which further leads to output reduction in forest-based and pulp & paper industries. The policy implementation, however, simulates production increase in other agricultural activities, notably in oil palm plantation. Furthermore, results simulations with the logging output-based subsidy suggest the magnitude of economic impacts is reduced from what would otherwise occur in the scenario of implementing RIL only (no subsidy is provided). The RIL policy also seems to result in ̳unexpected‘ emissions leakage indicated by increases in output of some agricultural-based activities such as oil palm plantation, other estate crops, and food crops. Increase in emissions is also expected to occur outside the Berau District stimulated by the increase in the District‘s import of timber.
53

Forest, Livelihoods and REDD+ implementation in the Yasuni Biosphere Reserve, Ecuador

Loaiza Lange, Toa 27 January 2017 (has links)
Wälder sind lebenswichtige Nahrungs- und Einkommensquellen für ländliche Haushalte und dienen als Reserven in Krisenzeiten. Deshalb können Abholzung und Walddegradierung die Lebensbedingungen der waldabhängigen Gemeinschaften gefährden. Darüber hinaus ist Abholzung die zweitgrößte Ursache für Treibhausgasemissionen, Biodiversitätsverlust und Klimawandel. Der ländliche Raum bedarf einer besonderen Aufmerksamkeit, da er sehr anfällig für die Auswirkungen des Klimawandels ist. In diesem Zusammenhang ist REDD+ als eine günstige Alternative zur Verringerung des Klimawandels und zur Förderung einer nachhaltigen Entwicklung aus dem Rahmenübereinkommen der Vereinten Nationen über Klimaänderungen (englisch United Nations Framework Convention on Climate Change, UNFCCC) hervorgegangen. Allerdings sind die potenziellen positiven und negativen Auswirkungen von REDD+ noch relativ unbekannt. Das gilt ins besondere für indigene Völker und andere vom Wald abhängige Bevölkerungsgruppen in tropischen Regenwäldern. Die hier vorgestellte Forschung ist eine mehrschichtige Studie, die dazu beiträgt, mögliche Alternativen der REDD+ Implementierung aus einer Bottom-up-Perspektive zu erklären. Als Fallstudie wurde die Yasuní-Region im gleichnamigen ecuadorianischen Biosphärenreservat ausgewählt. Die Region ist Teil eines größeren REDD+ Projektes der Deutschen NRO Welthungerhilfe. Hier wurden die drei am weitesten verbreiteten ethnischen Gruppen ausgewählt, die in der Pufferzone des Yasuní-Nationalparks leben. Zwei Gemeinden von jeder Ethnie mit jeweils unterschiedlichen Entfernungen zu den Märkten wurden als Studiengruppen ausgewählt. Hierbei handelt sie sich um die indigenen Gruppen der Shuar und Kichwa sowie die Gruppe der Kolonisten (Mestizen). Der Mehrskalenansatz umfasst die Haushaltsebene, die Gemeindeebene sowie die regionale Landschaftsebene. Auf der Haushaltsebene wird eine Analyse der Einkommensgenerierung, die sich aus der Subsistenzwirtschaft und der Barmitteleinnahme zusammensetzt, vorgestellt. Zusammenfassend lässt sich feststellen, dass die Mehrheit der untersuchten Haushalte hohe Einnahmen von Ölfirmen erhalten, denen sie als ungelernte nicht-landwirtschaftliche Arbeitskräfte zur Verfügung stehen. Darüber hinaus bezieht ein Großteil der Haushalte staatliche Unterstützungen. Die Studie zeigt, dass die indigenen Völker trotzt der vergleichsweise hohen Einkünfte aus ihrer Arbeit im Ölsektor und externer Hilfen eine größere Abhängigkeit von Wald- und Umweltressourcen als die Kolonisten haben. Dieses hohe nicht-landwirtschaftliche Einkommen könnte - zumindest zeitweise - den Druck auf die Wälder reduzieren. Vor diesem Hintergrund ist REDD+ ein relativ schwacher finanzieller Anreiz für die untersuchten Haushalte. Dies gilt umso mehr, wenn man das Engagement in mehrjährigen REDD+ Projekten wie Wiederaufforstung, Waldüberwachung usw. betrachtet. Auf Gemeindeebene werden die Landkonfiguration und der institutionelle Rahmen für die Entscheidungsfindung gemeinsamer Ressourcen analysiert. In dieser Studie werden zwei Formen kommunaler Vereinbarungen vorgestellt: Common Property Management Regimes (CPMRs) und Kolonisten-Kooperativen. Als konzeptioneller Rahmen wird der theoretische Ansatz von Ostrom (1990) zur Governance of Common Pool Resources (CPR) verwendet. Die Ergebnisse deuten darauf hin, dass sich immer mehr indigene Landkonfigurationen denen der Mestizen angleichen. Hinterlassenschaften aus Agrarreformen und geltende rechtliche Rahmenbedingungen fördern die Privatisierung der bäuerlichen Betriebe in den Gemeindeländern und damit die Waldzersplitterung. Dieses wiederrum beeinflusst die traditionelle Ressourcennutzung. Auf Landschaftsebene werden eine historische und territoriale Konfiguration sowie Managementpläne für das Biosphärenreservat Yasuní vorgestellt. Darüber hinaus werden rechtliche Rahmenbedingungen für REDD+, Konsultations- und Beteiligungsmechanismen diskutiert. Ergebnisse der Datenanalyse zeigen, dass unsichere Landadministration sowie Titelrechte die REDD+-Implementierung behindern können. Des Weiteren kommt es zu einer Überlappung von indigenem Land mit Erdölblöcken und Naturschutzgebieten, wodurch es zu potentiellen Konflikten kommen kann. Darüber hinaus verringern inkonsistente Managementplänen und rechtliche Rahmenbedingungen die effektive Beteiligung und Entscheidungsfindung von indigenen Völkern und Kleinbauern. Schlussfolgerung der Analyse ist, dass es einer breiten und eingebetteten Landschaftsplanung der Yasuní Region bedarf. Das Livelihood Framework Konzept wurde häufig angewandt, um die Haushaltsbedingungen und Verwendungsmuster von Umweltressourcen zu untersuchen. Diese Prägungen können Entwaldung, Erhaltung oder Abbauprozesse vorhersagen und beeinflussen. Erkenntnisse, wie die hier vorgestellten, verdeutlichen jedoch die Notwendigkeit von Bottom-up-Perspektiven vor der Umsetzung globaler Klimaschutzmechanismen wie REDD+. In praktischer Hinsicht liefern die Studienergebnisse Einblicke zur Konzeption von REDD+ Ansätzen für Projektentwickler und Entscheidungsträger. Die partizipative und intensive Beteiligung der lokalen Gemeinden an der Waldnutzung ist der einzige Weg, um die Erhaltung und nachhaltige Entwicklung der tropischen Wälder zu gewährleisten. Darüber hinaus sollten die ethnische Diversität sowie die traditionelle Ressourcennutzung aufrecht erhalten und gefördert werden. / Los bosques representan fuentes vitales de alimentos e ingresos para los hogares rurales, en especial durante períodos de crisis. Por lo tanto, la deforestación y la degradación forestal pueden poner en peligro los medios de subsistencia de las comunidades que dependen de los bosques. Además, la deforestación es la segunda causa más importante de emisiones de Gases Efecto Invernadero (GEI) y desencadena la pérdida de biodiversidad y el cambio climático. Los medios de subsistencia rurales necesitan una atención especial, ya que son altamente vulnerables a los efectos del cambio climático. En este contexto, REDD+ ha surgido en la mesa de negociación de la Convención marco de las Naciones Unidas para el Cambio Climático (CMNUCC) como una opción asequible para mitigar el cambio climático y, al mismo tiempo, para promover el desarrollo sostenible. Sin embargo, se necesita una mejor comprensión de los potenciales impactos positivos y negativos de la implementación de REDD+. Esto último, es especialmente importante en el caso de los Pueblos Indígenas (IP) y los campesinos dependientes de los bosques tropicales. La investigación presentada es un estudio a varios niveles que contribuye a elucidar las posibles implicaciones de la implementación de REDD+ desde una perspectiva de local hasta internacional. La región de la Reserva de la Biosfera del Yasuní en Ecuador fue seleccionada como estudio de caso. La región es parte de un proyecto REDD+ realizado por la ONG alemana Welthungerhilfe. Aquí se eligieron los tres grupos étnicos más representativos que habitan en la zona de amortiguamiento del Parque Nacional Yasuní. Se seleccionaron como grupos de estudio dos comunidades de cada etnia, los grupos indígenas Shuar y Kichwa y los colonos (mestizos), con diferentes distancias a los mercados. El enfoque multiescalar comienza en el nivel del hogar, luego sube a la comunidad y al final al nivel del paisaje regional. A nivel de hogar, se presenta un análisis de la generación de ingresos a partir de fuentes de subsistencia y dinero en efectivo. En resumen, todas las comunidades estudiadas generan altos ingresos fuera de la finca como mano de obra no calificada trabajando para las compañías petroleras y reciben ayuda externa. El estudio también muestra que los Indígenas tienen una mayor dependencia de los recursos forestales y ambientales en comparación con los colonos. Eventualmente, estos altos ingresos generados fuera de la finca podrían reducir, al menos temporalmente, la presión sobre los bosques. En este contexto, REDD+ constituye un incentivo débil para los hogares estudiados cuando se compara con los altos ingresos de la mano de obra no calificada. Esto se aplica aún más cuando se considera el involucramiento en las actividades del proyecto de REDD+ que requieren mucho tiempo, como la reforestación, monitoreo forestal, etc. A nivel comunitario, se analiza la configuración de la tierra y el marco institucional para la toma de decisiones sobre los recursos compartidos. Aquí se presentan dos formas de arreglos comunales: Regímenes Comunes de Gestión de la Propiedad (CRPM) y Cooperativas de Colonos. El marco teórico de Ostrom (1990) sobre la gobernanza de los recursos communes (CPR) se utiliza como marco conceptual. Los resultados sugieren que cada vez más, tanto la configuración de la tierra de las IP como las organizaciones comunitarias están adquiriendo características mestizas. Este mestizaje promovido parcialmente por el gobierno a través de los legados de la Reforma Agraria y los actuales marcos legales está desencadenando la privatización de las fincas dentro de las tierras comunitarias y por lo tanto promoviendo la fragmentación del bosque y afectando las formas ancestrales de regularización para el uso de los recursos. A nivel del paisaje se presenta una revisión de la configuración histórica y territorial así como los planes de manejo para la Reserva de la Biosfera Yasuní. Además, se discuten marcos legales para REDD+, así como mecanismos de consulta y participación. De acuerdo con los datos del presente estudio, la inseguridad en la administración de la tierra y los derechos de titulación pueden obstaculizar la implementación de REDD+ y generar conflictos debido a la superposición de tierras indígenas con bloques de petróleo y áreas protegidas. Además, las incoherencias entre los planes de gestión y los marcos jurídicos reducen la participación efectiva y la toma de decisiones de los Inddígenas y los pequeños agricultores. El análisis concluye sugiriendo una visión de paisaje amplia e integrada para el área del Yasuní. El marco teórico de medios de vida (Lifelihood Framewrok) se ha utilizado comúnmente para estudiar las condiciones de los hogares y generar patrones de uso de recursos ambientales que pueden moldear y predecir procesos de conservación, deforestación o degradación. Sin embargo, intentos como el presentado aquí ejemplifican la necesidad de perspectivas ascendentes previo a la implementación de mecanismos globales de mitigación como REDD+. Desde la perspectiva práctica, los resultados proporcionan nuevas percepciones para los desarrolladores de proyectos y los formuladores de políticas para el diseño de enfoques REDD+. La verdadera y plena participación de las comunidades locales en la gobernanza de los bosques es la única manera de alcanzar la conservación y el desarrollo sostenible de los bosques tropicales. Además, igual de importantes son la diversidad pluricultural y la promoción de reglas tradicionales para el uso de los recursos, así como las prácticas tradicionales.
54

Forest Conservation and the Hadzabe. An integrated approach in protecting biodiversity and cultural diversity. Case study: Carbon Tanzania.

Fassbender, Sabrina January 2016 (has links)
Preventing emissions from deforestation is propagated as an effective strategy to combat climate change. At the same time forest landscapes are habitat to the last remaining traditional societies of this planet. For a long time forest conservation programs neglected the role of these indigenous communities for forest landscapes. Historical ecology pushes a change of environmental narratives towards an understanding that biocultural diversity has had and will have a significant impact on resource use and on the transformation of landscapes. A growing number of debates on global environmental justice and poverty alleviation goals call for such an integrated approach in protecting biodiversity and cultural diversity when conserving forest landscapes. Although this topic is discussed, there is a gap in scientific literature on how such an approach can actually be implemented in practise. This paper examines how the dual-objective of forest conservation and protection of cultural diversity can be achieved in practise by applying a case study of a conservation project, Carbon Tanzania. Carbon Tanzania is operating in an area in northern Tanzania inhabited by one of the few remaining hunting and gathering societies on the planet, the Hadzabe. Carbon Tanzania conservation project issues carbon credits which can be bought by companies, organisations and individuals to offset their emissions. Interviews with the different actors have been conducted in the course of the research project in order to examine how Carbon Tanzania’s ‘community-led project’ contextualizes the dual objective of protecting forests and the Hadzabe culture. The results show that the implementation of the project is facilitated through an integrated network of different actors and organisations. Critical for the operations in the area is secured land ownership and a binding land use plan in order to protect the area from external pressure and to manage the utilization of the landscape by the different communities within the area. Payments for ecosystem services generate benefits for the local forest community and support community development. This form of ‘productive’ land utilization offers a path in changing development narratives for African countries.
55

The Price of Protecting Forests : Assessing REDD+ Performance in Collaborative Governance in Vietnam

Grönlund Müller, Molly January 2019 (has links)
The UNFCCC initiated mechanism Reducing Emissions from Deforestation and Forest Degradation (REDD+) is an important policy instrument for combating climate change, using payments to create economic incentives for developing countries to preserve their forests. However, there is a need for closer scrutiny of whether the mechanism is able to generate its intended outputs and outcomes. The study assessed REDD+ productivity performance in collaborative governance using an instrumental case study of a Collaborative Governance Regime (CGR), the CarBi project in Vietnam. The assessment was based on Emerson and Nabatchi’s productivity performance matrix encompassing three units of analysis - the Participant Organisations, the CGR and the Target Goals. The study was conducted as a Minor Field Study (MFS) using in-depth interviews, complemented with official documents. The findings showed that progress was made in achieving target goals such as forest restoration and enhanced biodiversity, but that REDD+ was not adapted to suit the CGR’s need for stable payments and was not financially feasible to implement in a conservation focused project. Instead, outputs and outcomes were sustained as a result of the transition to the national Payment for Forest Ecosystem Services (PFES). However, the REDD+ safeguards, supporting the inclusion of local communities and indigenous peoples, were lost in the transition and PFES reliance on funding from hydropower dams posed both environmental and social challenges to CGR sustainability.
56

Papel do direito na implementação de projetos  de PSE e REDD+ / The role of law in the implementation of PES/REDD+ projects

Cunha, Tiago Ferreira da 13 April 2015 (has links)
A presente dissertação de mestrado consiste em um estudo de caso de três programas de pagamento por serviços ecossistêmicos - PSE, que ajudaram a definir o papel que o direito deve assumir na implementação e manutenção desses mecanismos. Buscou-se, primeiramente, delimitar algumas bases teóricas, sobretudo, o que se entende por desenvolvimento sustentável e sustentabilidade institucional. Para tanto, optamos por demonstrar a evolução conceitual de serviços ambientais para serviços ecossistêmicos e entender este como uma segunda fase daquele, destacando os reflexos desse entendimento na estrutura jurídica dos programas de pagamento por serviços ambientais, que optamos por chama-lo de pagamento por serviços ecossistêmicos. Em seguida, descrevemos toda a evolução das discussões sobre REDD+, exemplo de PSE, para enfatizar os desafios que o direito assume com essa nova concepção de serviços ecossistêmicos. A experiência indica que o sucesso dos programas analisados são, em grande medida, consequência da ideia de função promocional do direito, bem como da observação das suas funcionalidades, quais sejam, orquestração, sinergia, flexibilização e legitimidade, que garantem, antes de mais nada, a sustentabilidade institucional dos mecanismos, permitindo sua perfeita adequação à realidade em que se insere e, mais do que isso, permitindo a manutenção desses instrumentos, mesmo diante de mutações do meio em que estão inseridos. / This master\'s thesis consists of a case study of three payment programs for ecosystem services - PSE, which helped define the role of law should take the implementation and maintenance of these mechanisms. We tried to, first, define some theoretical bases, above all, what is meant by sustainable development and institutional sustainability. Therefore, we chose to demonstrate the conceptual evolution of environmental services for ecosystem services and understand this as a second phase that, highlighting the consequences of this understanding the legal structure of payment for environmental services programs we chose to call it payment for ecosystem services. We then describe the whole evolution of discussions on REDD+, PES example, to emphasize the challenges that the right has with this new concept of ecosystem services. Experience indicates that the success of the analyzed programs are to a large extent the consequence of the idea of promotional function of law and the observation of its features, namely, orchestration, synergy, flexibility and legitimacy that ensure, first of all , institutional sustainability mechanisms, allowing its perfect adaptation to the reality in which it operates and, more than that, allowing the maintenance of these instruments, even in the face of the changing environment in which they live.
57

Papel do direito na implementação de projetos  de PSE e REDD+ / The role of law in the implementation of PES/REDD+ projects

Tiago Ferreira da Cunha 13 April 2015 (has links)
A presente dissertação de mestrado consiste em um estudo de caso de três programas de pagamento por serviços ecossistêmicos - PSE, que ajudaram a definir o papel que o direito deve assumir na implementação e manutenção desses mecanismos. Buscou-se, primeiramente, delimitar algumas bases teóricas, sobretudo, o que se entende por desenvolvimento sustentável e sustentabilidade institucional. Para tanto, optamos por demonstrar a evolução conceitual de serviços ambientais para serviços ecossistêmicos e entender este como uma segunda fase daquele, destacando os reflexos desse entendimento na estrutura jurídica dos programas de pagamento por serviços ambientais, que optamos por chama-lo de pagamento por serviços ecossistêmicos. Em seguida, descrevemos toda a evolução das discussões sobre REDD+, exemplo de PSE, para enfatizar os desafios que o direito assume com essa nova concepção de serviços ecossistêmicos. A experiência indica que o sucesso dos programas analisados são, em grande medida, consequência da ideia de função promocional do direito, bem como da observação das suas funcionalidades, quais sejam, orquestração, sinergia, flexibilização e legitimidade, que garantem, antes de mais nada, a sustentabilidade institucional dos mecanismos, permitindo sua perfeita adequação à realidade em que se insere e, mais do que isso, permitindo a manutenção desses instrumentos, mesmo diante de mutações do meio em que estão inseridos. / This master\'s thesis consists of a case study of three payment programs for ecosystem services - PSE, which helped define the role of law should take the implementation and maintenance of these mechanisms. We tried to, first, define some theoretical bases, above all, what is meant by sustainable development and institutional sustainability. Therefore, we chose to demonstrate the conceptual evolution of environmental services for ecosystem services and understand this as a second phase that, highlighting the consequences of this understanding the legal structure of payment for environmental services programs we chose to call it payment for ecosystem services. We then describe the whole evolution of discussions on REDD+, PES example, to emphasize the challenges that the right has with this new concept of ecosystem services. Experience indicates that the success of the analyzed programs are to a large extent the consequence of the idea of promotional function of law and the observation of its features, namely, orchestration, synergy, flexibility and legitimacy that ensure, first of all , institutional sustainability mechanisms, allowing its perfect adaptation to the reality in which it operates and, more than that, allowing the maintenance of these instruments, even in the face of the changing environment in which they live.
58

Reproductive ecology and success of sea trout Salmo trutta L. in a small lowland stream of Western Lithuania / Šlakių Salmo trutta L. reprodukcijos ekologija ir efektyvumas mažame lygumų upelyje Vakarų Lietuvoje

Nika, NERIJUS 20 February 2012 (has links)
Reproduction is a critical period of salmonid fish life history. As early life stages are particularly sensitive to biotic and abiotic constraints, studying these stages in terms of survival is essential in salmonid population ecology, stocks management, conservation and restoration. No characterization of salmonids spawning habitats on scientific basis has been made to date in Eastern Baltic region, which rivers are important for salmonid reproduction and significantly contribute to the sea trout and salmon stocks in the Baltic. The aim of this work was to assess sea trout spawning sites characteristics and to estimate its effects on reproductive success in a typical lowland salmonid stream – Blendžiava. The spawning site selection by sea trout females and characteristics of spawning sites at different spatial scales were determined, spawning nests sedimentary, hydraulic, and water physico-chemical characteristics were assessed. To test how the spawning site selection influence reproductive success, in situ experiment on survival of sea trout eggs, study on fry emergence from natural redds and on dispersal of juveniles after emergence were accomplished. Additionally, the study on reproductive interaction between sympatric lampreys and salmonids was conducted. Study results revealed, that sea trout has specific spawning site preferences at the stream-, reach- and microhabitat scale, and are related with optimal conditions for egg survival. Vertical hydraulic gradient of... [to full text] / Reprodukcija yra kritinis lašišinių žuvų gyvenimo momentas. Kadangi ankstyvosios vystymosi stadijos yra ypač jautrios biotiniams ir abiotiniams veiksniams, šių stadijų tyrimai yra esminiai lašišinių žuvų populiacijos ekologijai, valdant, apsaugant ir atstatant išteklius. Tačiau mokslinių lašišinių žuvų reprodukcijos tyrimų iki šiol nebuvo atlikta Rytų Baltijos regione, kurio upės yra svarbios lašišinių žuvų reprodukcijai ir jų ištekliams Baltijos jūroje. Šio darbo tikslas buvo nustatyti šlakių neršto vietos pasirinkimo dėsningumus, naudojamų nerštaviečių charakteristikas ir įvertinti jų įtaką reprodukcijos efektyvumui tipiškoje lašišinėje lygumų upėje Vakarų Lietuvoje Blendžiavoje. Darbe buvo vertintas šlakių neršto vietų pasirinkimas ir charakteristikos skirtingo erdvinio mastelio buveinėse, nustatytos neršto lizdų substrato, hidraulinės ir porinio vandens fizikocheminės charakteristikos. Kad nustatyti, kaip lizdų charakteristikos įtakoja reprodukcijos efektyvumą, buvo atlikti šlakių ikrų inkubacijos in situ eksperimentai, mailiaus ritimosi iš natūralių lizdų ir pasklidimo iš nerštaviečių po upelį tyrimai. Taip pat buvo atlikta speciali studija, kad įvertinti lašišinių žuvų ir nėgių reprodukcinę sąveiką simpatrinėmis sąlygomis. Tyrimų rezultatai parodė, kad šlakiai turi specifinius reikalavimus neršto vietai upelio, vagos geomorfologijos ir mikrobuveinės mastu, ir yra susiję su optimaliomis palikuonių išgyvenimo sąlygomis. Vertikalusis hidraulinis gradientas buvo esminis... [toliau žr. visą tekstą]
59

Šlakių Salmo trutta L. reprodukcijos ekologija ir efektyvumas mažame lygumų upelyje Vakarų Lietuvoje / Reproductive ecology and success of sea trout Salmo trutta L. in a small lowland stream of Western Lithuania

Nika, NERIJUS 20 February 2012 (has links)
Reprodukcija yra kritinis lašišinių žuvų gyvenimo momentas. Kadangi ankstyvosios vystymosi stadijos yra ypač jautrios biotiniams ir abiotiniams veiksniams, šių stadijų tyrimai yra esminiai lašišinių žuvų populiacijos ekologijai, valdant, apsaugant ir atstatant išteklius. Tačiau mokslinių lašišinių žuvų reprodukcijos tyrimų iki šiol nebuvo atlikta Rytų Baltijos regione, kurio upės yra svarbios lašišinių žuvų reprodukcijai ir jų ištekliams Baltijos jūroje. Šio darbo tikslas buvo nustatyti šlakių neršto vietos pasirinkimo dėsningumus, naudojamų nerštaviečių charakteristikas ir įvertinti jų įtaką reprodukcijos efektyvumui tipiškoje lašišinėje lygumų upėje Vakarų Lietuvoje Blendžiavoje. Darbe buvo vertintas šlakių neršto vietų pasirinkimas ir charakteristikos skirtingo erdvinio mastelio buveinėse, nustatytos neršto lizdų substrato, hidraulinės ir porinio vandens fizikocheminės charakteristikos. Kad nustatyti, kaip lizdų charakteristikos įtakoja reprodukcijos efektyvumą, buvo atlikti šlakių ikrų inkubacijos in situ eksperimentai, mailiaus ritimosi iš natūralių lizdų ir pasklidimo iš nerštaviečių po upelį tyrimai. Taip pat buvo atlikta speciali studija, kad įvertinti lašišinių žuvų ir nėgių reprodukcinę sąveiką simpatrinėmis sąlygomis. Tyrimų rezultatai parodė, kad šlakiai turi specifinius reikalavimus neršto vietai upelio, vagos geomorfologijos ir mikrobuveinės mastu, ir yra susiję su optimaliomis palikuonių išgyvenimo sąlygomis. Vertikalusis hidraulinis gradientas buvo esminis... [toliau žr. visą tekstą] / Reproduction is a critical period of salmonid fish life history. As early life stages are particularly sensitive to biotic and abiotic constraints, studying these stages in terms of survival is essential in salmonid population ecology, stocks management, conservation and restoration. No characterization of salmonids spawning habitats on scientific basis has been made to date in Eastern Baltic region, which rivers are important for salmonid reproduction and significantly contribute to the sea trout and salmon stocks in the Baltic. The aim of this work was to assess sea trout spawning sites characteristics and to estimate its effects on reproductive success in a typical lowland salmonid stream – Blendžiava. The spawning site selection by sea trout females and characteristics of spawning sites at different spatial scales were determined, spawning nests sedimentary, hydraulic, and water physico-chemical characteristics were assessed. To test how the spawning site selection influence reproductive success, in situ experiment on survival of sea trout eggs, study on fry emergence from natural redds and on dispersal of juveniles after emergence were accomplished. Additionally, the study on reproductive interaction between sympatric lampreys and salmonids was conducted. Study results revealed, that sea trout has specific spawning site preferences at the stream-, reach- and microhabitat scale, and are related with optimal conditions for egg survival. Vertical hydraulic gradient of... [to full text]
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Revisiting patterns and processes of forest cover change in the tropics : a case study from southeast Mexico

Gueye, Kinne January 2018 (has links)
Vast progress has been made in detecting rates of tropical deforestation, yet the relationship between visible patterns of forest change, multi-scalar human processes and the underlying drivers associated with them is poorly understood. Building on satellite imagery, a household livelihood survey and semi-structured interviews, this research scrutinised changes of forest cover from the mid-1990s to 2015 in a municipality located in southeastern Mexico and investigated the proximate causes and underlying drivers of change at the household and community levels. Emerging evidence indicated that, contrary to the persistent narrative of deforestation for the region, forest cover change is highly dynamic including periods of deforestation and forest recovery. Moreover, a close examination of 24 communities showed forest cover gained terrain, while the agricultural frontier retracted. Drawing on a comparison between the household survey and previous analyses, it could be inferred that forest resurgence was produced by the decrease in the farming area and the increase in the abandonment of farming activities by some communities. Associated with the adaptation of households was the development of formal and informal institutions at the community level in response to macro-global forces linked to the implementation of forest conservation strategies, environmental degradation, market liberalization and increased urbanization. Overall, this research adds not only to our understanding of the complexity of land-use and cover change in emerging globalized economies but also exemplifies the spatial and temporal heterogeneity of tropical forest systems, which challenges partial models of deforestation and policies designed to reduce it. The research may be focused on a narrow region of the globe, nevertheless, the insights and recommendation provided may be useful to further forest conservation schemes in other tropical regions.

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