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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.
251

Non-industrial private forest owners’ harvesting decisions : An empirical study of forest owners’ harvesting decisions in Norrbotten

Grath, Brenden January 2023 (has links)
The forest plays a large role both nationally and internationally towards a sustainable planet. Therefore, understanding non-industrial private forest owners’ preferences is important to achieve the environmental targets, since they are a large ownership group in Sweden. The present study focusses on non-industrial private forest owners’ harvesting decisions in Norrbotten. Furthermore, the study extends to analyze how the forest owners’ preferences towards promotion of ecosystem services are affected if compensation is offered. To understand the harvesting decisions of non-industrial private forest owners’, an empirical approach was used where a questionnaire was constructed. The data were analyzed through logistic regression. The results suggest that non-industrial private forest owners’ harvesting decision is positively affected by previous experience in the forest, days present in the forest, membership in a forest cooperative and a price increase of timber. Forest owners with economic objectives harvest more than owners with no or other objectives. No significant relationship between nature- and economic objectives in the harvesting decisions were identified. The results related to willingness to promote ecosystem services for compensation indicated ambiguous results.
252

Plant biodiversity and ecosystem services in an Asian developed city: land use and scale / アジアの都市における植物の生物多様性と生態系サービス:土地利用とスケ-ル

KANG, Jiefeng 25 July 2022 (has links)
京都大学 / 新制・課程博士 / 博士(地球環境学) / 甲第24154号 / 地環博第232号 / 新制||地環||44(附属図書館) / 京都大学大学院地球環境学舎地球環境学専攻 / (主査)教授 柴田 昌三, 准教授 深町 加津枝, 教授 瀬戸口 浩彰 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM
253

Songbird-mediated Insect Pest Control in Low Intensity New England Agriculture

Mayne, Samuel J 21 March 2022 (has links)
Global agricultural intensification has caused large-scale wildlife declines, but agricultural lands that maintain natural habitats can support healthy wildlife populations and receive significant ecosystem services from these natural communities. However, how on-farm biodiversity results in beneficial ecosystem services is highly variable and is reported to differ among taxa and guilds. One group that has attracted attention for their potential beneficial role in reducing pest abundance are birds. Understanding the role of bird communities and individual species in pest control could be important for managing farms under a low intensity agroecological framework. In New England, farmers are increasingly applying low intensity agricultural practices, and these low intensity farms have high conservation value for bird communities. The value of bird communities to on-farm productivity, however, remains poorly understood. Therefore, we quantified the amount of insect pest control provided by birds to three important crops to New England farmers: brassicas (e.g., kale, broccoli), cucurbits (e.g., squash, cucumber), and Solanaceae (e.g., eggplant, potato). We also examined the role of different songbird species in the provision of pest control in this system. To determine the amount of pest control services provided by birds in this system, we conducted an exclusion experiment at nine low intensity farms in Franklin and Hampshire counties of Massachusetts. Birds were excluded from crops, and pest abundance and leaf damage were compared between exclusion plots and immediately adjacent control plots. In brassica crops, the abundance of imported cabbageworm (Pieris rapae) and diamondback moth (Plutella xylostella) were significantly reduced, while cabbage looper (Trichoplusia ni) was not significantly affected. In cucurbit crops, all life stages of squash bugs (Anasa tristis) were significantly reduced, though striped cucumber beetle (Acalymma vittatum) populations were not significantly changed. In Solanaceous crops, bird presence caused significantly larger populations of Colorado potato beetle (Leptinotarsa decemlineata) larvae, while the other life stages of Colorado potato beetle and aphids (superfamily Aphidoidea) were not significantly affected. Leaf damage was reduced by bird presence in all three crop types, though this effect was only significant for cucurbits. The varied effects of bird predation in different crop types highlights the need for crop-specific knowledge in applying agroecological pest management in New England. To determine the roles of different bird species in insect pest control, bird diets were studied at 11 low intensity farms in western Massachusetts. DNA metabarcoding was used to determine the frequency of crop pests and pest natural enemies in fecal samples collected from birds on each farm. We found evidence of pest species being consumed in 12.6% of the 737 total fecal samples collected, while pest natural enemies were present in 2.0% of samples. Among bird species, Gray Catbirds and Common Yellowthroats were determined to feed on crop pests significantly more frequently than Song Sparrows, while no bird species effect was found for natural enemy frequency. The only crop pest surveyed in our exclosure experiment which was present in fecal samples was Colorado potato beetle. Though birds preyed on Colorado potato beetle, they also preyed on two known predators of Colorado potato beetle eggs and larvae: Chrysopa oculata and Chrysoperla rufilabris. This provides evidence that the increase in Colorado potato beetle larvae we observed when birds were present was due to ecological release. Combined, our results show that birds provide important, though variable, insect pest control services on low intensity New England farms. Bird predation had primarily beneficial impacts on crops, suppressing abundance of several pest species and decreasing or minimally affecting leaf damage. The effects of bird predation on pest abundance and damage can be integrated into farm management to control insect pests without reliance on expensive, and sometimes damaging, outside inputs like pesticides. Promotion of woody, non-crop habitats on farms can promote species like Gray Catbirds and Common Yellowthroats that feed more frequently on insect pests. Management of New England farmlands for bird pest control may support healthy bird communities and improve agricultural output.
254

Pollinerare, ekosystemtjänster, avkastning, pollinator, ecosystem services & yield

Lidén, Linnea, Melander, Anders January 2019 (has links)
Ljudet av surrande insekter har blivit mer sällsynt på senare år och det finns en risk att det kommer bli en betydlig minskning av det i framtiden. Det menar i alla fall oroande forskarrapporter. En stor del av insekterna kan var utrotningshotade och det innebär i sin tur en risk för hela ekosystemet. Ekosystemtjänsterna kopplade till det svenska jordbruket från pollinerare är försörjande och reglerande. Kulturella tjänster från pollinerare finns också, i form av friluftsliv och bärplockning bland annat. Några viktiga pollinerare i Sverige är steklar och mer specifikt humlor och bin. Av de 299 vilda biarterna i Sverige är en tredjedel hotade. Jordbruket är i behov av pollinering för de grödor där självpollinering inte kan ske, dessa är till stor del frukt och grönsaker men även raps. Raps är till viss del självpollinerande, forskningen pekar på att skörden mognar jämnare och avkastningen blir bättre vid en högre närvaro av pollinerare. Detta är av stor vikt för att det ska vara lönsamt att bedriva jordbruksverksamhet därför bör dessa värna om denna ekosystemtjänst som pollinerare bidrar till. Denna rapport tar upp situationen för pollinerare i Sverige och hur de bidrar till olika ekosystemtjänster, fokus ligger på rödlistade arter och dess hot och problematik. Hur närvaron av pollinerare påverkar skörden och avkastningen av raps undersöks för att försöka uppskatta det ekonomiska värdet av pollinerare. En mindre fallstudie genomfördes för att vidare se hur förutsättningarna ser ut för pollinerare i ett begränsat område. En litteraturstudie har legat som grund för denna studie och har begränsats till den data som finns. För pollinerare har det funnits information om steklar (humlor och bin), en geografiskbegränsning till Öland och ett område utanför Gårdby gjordes. I fallstudien framkom det att observationerna av pollinerare skedde sporadiskt och att det finns kunskapsluckor i det valda området. Därför är det viktigt att vidare öka intresset och kunskapen om hur människor varje dag påverkar och nyttjar ekosystemtjänster från pollinerare. Hoten och problematiken identifieras ett av dem var förändrad markanvändning, i form av att förutsättningarna för att överleva inte längre är de samma. Det kan ta sig formen av ett intensifierat jordbruk där tillgången på en varierad föda inte längre finns men också att boplatser växer igen. En lösning till den hastiga förändringar i markanvändningen är att odla mer ekologiskt och ta tillvara på de naturliga områden då de bidrar till en hög biodiversitet. Detta motverkar även intensifieringen av jordbruket som idag går mot att bestå av stora monokulturer. Det andra hotet var insektsmedel generellt, då det har visats att det kan ha en negativ påverkan på pollinerare då främst på deras larver och ägg. Därtill är rekommendationerna för produkttester väldigt korta vilket resulterar i att de fullständiga effekterna alltid syns. Problematiken med insektsmedel har två lösning, en där odling i större utsträckning sker ekologiskt och att genomföra längre tester. Övriga potentiella hot är den överhängande klimatförändringen, sker det en snabb förändring förändras förutsättningarna drastiskt. Även inplantering av odlade pollinerare kan potentiellt vara ett hot då de kan konkurrera ut de vilda pollinerarna. / The sound of buzzing insects have become more scarce in the last several years and there is an overhanging risk that There will be a major decrees of them in the future. There is some scientific research that claims so, and that is worrying. A big part of the insects could be endangered and that would mean that the existence of ecosystems is at great risk. Farming in Sweden relies on several ecosystem services from pollinators, mainly provisioning and regulating. There are some cultural services from pollinators as well, that mostly affects outdoor life and the picking of berries among others. Some of the important pollinators are bumblebees and bees. Out of the 299 wild species that live in Sweden a third is threatened. Farmers are in need of pollination of the crops that don't self-pollinate, these crops are mainly fruit and vegetables but also oilseed rape. Oilseed rape is to some extent self-pollinating, but research shows that the yield ripens more evenly and the turnover of the crop is increased by a higher level of presence in the field by pollinators. This is of great interest for the farmers to make their business profitable, therefore they should work to preserve the ecosystem services that pollinators contribute with. This report attends the situation of pollinators in Sweden and how they contribute to ecosystem services, it's focused on red-listed species and their threats and problems. Also how the presence of pollinators affects the yield of rapeseed oil is investigated to try to estimate the value of pollinators. A smaller case study was conducted to further see how the conditions for pollinators are in a limited area. A literature study has laid the path for this study and it has been limited to the data available. for pollinators information about bees and bumblebees have been available, and a geographic limitation to Öland and to an area outside Gårdby was made. A small case study was conducted to further show the condition of pollinators in a limited area. It was shown that the observations of pollinators were sporadically conducted and there was a lack of knowledge in the chosen area. Therefore it's important to further increase the interest and knowledge about how humans affects and uses the ecosystem services from pollinators every day. The identified threats was a change in land use, to such an extent that it affects the conditions of surviving. It could be caused by intensified farming were the access to sufficient food is no longer available to pollinators. Increased land use changes the natural habitats where pollinators build their nests, either because they overgrow or they are exploited to uninhabitable ground. A solution to this is ecological farming where natural regions contribute to a greater biodiversity in the landscape are seen as a resource and preserved. The increased intensification of farming land will decrease if a large part of the farming is done ecologically. The second threat was pesticides in general, it has been shown that it could have a negative impact on pollinators, and mostly the larva’s and eggs. In addition to that, the recommendation on how long to test for the effects of a pesticide is very short. These problems with pesticides have two solutions, one was an increase in ecological farming and also to conduct longer test periods for pesticides. Other potential threats that were identifies was the overhanging climate change, conditions would drastically change. A presence of domesticated pollinators could be rival to native pollinators and lead to a decrease of native pollinators.
255

Go Fish: An Analysis Of Economic Rents In Panamanian Fisheries Against Ecosystem Service Values

Glassner, David 01 January 2013 (has links)
Global demand of fish for consumption in developing nations is expected to continue to rise in the near future, putting pressure on stocks that are already overexploited. In the territorial waters of Panama there is a constant struggle between commercial vessels with high yield, subsistence fishermen trying to feed a remote village, and ecosystem services struggling to sustain themselves. These services are the direct and indirect benefits received by the population in the form of food, raw materials, nutrient cycling, and disaster regulation. They are being degraded by illegal and unregulated fishing, bottom trawlers raking the benthos and destroying coral reefs, longlines responsible for thousands of sea turtle and bird deaths, and purse seines that decrease species biodiversity in fish stock. While the government has passed laws to reduce the environmental impact the industrial fisheries have, they lack effective enforcement. An alternative approach is to place monetary values on ecosystem services to show the monetary value of previously unrepresented natural capital. Application of this method to fisheries management can educate policy makers on the economic losses to expect if overfishing of the seas continues and provide the economic imperative to lessen impacts on oceanic ecosystems. Through comparative analysis it is shown that the market value of all fish catch in Panamanian waters is less than that which is provided by the ecosystem services in the area. Open ocean and coral reef ecosystem services provide a combined $103 billion per year while the highest grossing fish catch in Panamanian waters managed to net $356 million in 2004. There is an economic and political imperative to protect and promote sustainability of not only the fish stock, but all ecosystem services in the ocean.
256

Effects of Wildland Urban Interface Fuel Treatments on Fire Behavior and Ecosystem Services in the Klamath Mountains of California

Large, Jonathan A 01 August 2010 (has links) (PDF)
Greater numbers of people are moving into wildland-urban interface (WUI) areas, increasing the number of people at risk to large wildfires. To mitigate the hazard, emphasis is often placed on fuel treatments used to reduce fuel loads and subsequent fire behavior. This approach overlooks the additional benefits provided by vegetation, including carbon storage and sequestration along with air pollutant removal. This study aimed to calculate and compare differences in representative values by examining a study site in the Klamath Mountains of Northern California. Fire behavior simulations were done under various weather scenarios to illustrate both the impact of weather on fire intensity as well as the limitations of various fuel treatments. Ecosystem services were modeled using the I-tree Eco software (formerly the Urban Forest Effects model). Results showed a reduction in surface and an increase in canopy base height from the treatments and subsequent reductions in fire intensity under moderate and high conditions with the largest difference occurring in the Thin + Fire treatment. Under extreme weather conditions, the effectiveness of all fuel treatments was reduced. Ecosystem services showed a reduction of carbon sequestration in the fuel treatments corresponding to the reduction of smaller diameter trees from the fuel treatments. The greatest difference occurred in the Thin + Fire treatment. These results and the methods used to acquire them show the impacts from fuel treatments can be characterized and compared. This information will allow land managers to make decisions that account for a variety of considerations, while also providing them with tools that can facilitate the cooperation and collaboration of multiple stakeholders.
257

The Influence of the Sensory Environment on Avian Reproductive Success and Human Well-Being

Ferraro, Danielle Marie 01 June 2020 (has links) (PDF)
Sensory pollutants such as anthropogenic noise and night lighting now expose much of the world to evolutionarily novel sound and night lighting conditions, which can have detrimental effects on humans and wildlife. In my first chapter, we exposed wild Western Bluebird (Sialia mexicana) nestlings to noise, light, and combination (i.e., noise and light) treatments. Nests exposed to noise and light together experienced less predation than control and light-exposed nests, and noise-exposed nests experienced less predation than control nests, yet overall nest success was only higher in noise-exposed nests compared to light-exposed nests. Although exposure to light decreased nestling body condition and evidence was mixed for the singular effects of noise or light on nestling size, those exposed to noise and light together were smaller across several metrics than nestlings in control nests. Our results support previous research on the singular effects of either stimuli, including potential benefits, such as reduced nest predation with noise exposure. However, our results also suggest that noise and light together can negatively affect some aspects of reproduction more strongly than either sensory pollutant alone. This finding is especially important given that these stimuli tend to covary and are projected to increase dramatically in the next several decades. In my second chapter, we used a field-based manipulation to explore the role of audition in biodiversity perception and self-reported well-being of hikers. We used a “phantom chorus” consisting of hidden speakers playing bird vocalizations to experimentally increase audible birdsong biodiversity during “on” and “off” blocks on two hiking trails and surveyed hikers to record their self-reported perceptions of avian biodiversity and concepts reflective of attention restoration. We found that hikers exposed to the phantom chorus reported higher levels of restorative effects compared to those that experienced ambient conditions on both trails, although the causal relationships differed for each trail. Specifically, increased restorative effects were directly linked to the phantom chorus on one trail and indirectly linked to the phantom chorus on the other trail through perceptions of avian biodiversity. Our findings add to a growing body of evidence linking mental health improvements to nature experiences and, via our field-based manipulation, we identified audition as an important modality by which natural environments confer well-being. Finally, our results suggest that maintaining or improving natural soundscapes within protected areas may be an important component to maximizing human experiences, especially as tourism and noise pollution in protected areas grow.
258

An Assessment of Non-Apis Bees as Fruit and Vegetable Crop Pollinators in Southwest Virginia

Adamson, Nancy Lee 22 March 2011 (has links)
Declines in pollinators around the globe, notably the loss of honey bees (Apis mellifera L.) to Colony Collapse Disorder, coupled with a dearth of quantitative data on non-Apis bee pollinators, led to this dissertation research, which documents the role of non-Apis bees in crop pollination in southwest Virginia. Major findings of this first study of its kind in the region were that non-Apis bees provided the majority of pollination—measured by visitation—for several economically important entomophilous crops (apple, blueberry, caneberry, and cucurbits); diverse bee populations may be helping to stabilize pollination service (105 species on crop flowers); landscape factors were better predictors of non-Apis crop pollination service than farm management factors or overall bee diversity; and non-Apis bees in the genera Andrena, Bombus, and Osmia were as constant as honey bees when foraging on apple. Non-Apis, primarily native, bees made up between 68% (in caneberries) and 83% (in cucurbits) of bees observed visiting crop flowers. While 37–59 species visited crop flowers, there was low correspondence between bee communities across or within crop systems ("within crop" Jaccard similarity indices for richness ranged from 0.12–0.28). Bee community diversity on crop flowers may help stabilize pollination service if one or more species declines temporally or spatially. A few species were especially important in each crop: Andrena barbara in apple; Andrena carlini and A. vicina in blueberry; Lasioglossum leucozonium in caneberry; and Peponapis pruinosa and Bombus impatiens in cucurbits. Eight species collected were Virginia state records. In models testing effects of farm management and landscape on non-Apis crop pollination service, percent deciduous forest was positively correlated in apple, blueberry, and squash, but at different scales. For apple and blueberry, pollination service declined with an increase in utilized alternative forage but was positively related to habitat heterogeneity. For squash, percent native plants also related positively, possibly due to increased presence of bumble bees in late summer. Species collected from both bowl traps and flowers was as low as 22% and overall site bee diversity had no effect on crop pollination service, highlighting the value in pollination research of monitoring bees on flowers. / Ph. D.
259

Strategies for biodiversity, ecosystem services and climate adaptation in management of trees among actors in the city of Stockholm

Landenmark, Johan January 2022 (has links)
Urban trees provide a wide array of benefits and values for urban dwellers as a foundational part of the biodiversity, the generation of ecosystem services and mitigation of negative impacts of climate change. However, management in cities often fail to acknowledge the diversity of ecosystem services in urban landscapes needed for improving resilience. Through interviews with actors managing tree communities within the city of Stockholm, along with a review of municipal policy documents, this study explores the qualities, values and benefits, focusing on biodiversity, ecosystem services and climate change adaptation, that are considered when making decisions about tree management. The interview results and policy documents were analyzed using an analytical framework for three different phases of management: (i) goals, (ii) strategies and measures and (iii) monitoring and evaluation. Most of the actors to some extent consider biodiversity, ecosystem services and climate change adaptation through ecosystem services in management. The strategies of including a more diverse set of values and benefits are still in its early stages, which is reflected in a low degree of strategical work, lack of clearly defined goals and limited operationalization of the concepts, and few actors work with monitoring and evaluation. However, more aspects of biodiversity and ecosystem services are gaining attention within management, and there is an ambition to incorporate such values to a greater extent.
260

Ocean Economy - Implementing damages to marine sectors and ecosystems into the DICE model / Ocean Economy - Implementering av skador på marina sektorer och ekosystem i DICE-modellen

Gleim, Malte January 2023 (has links)
The oceans are a key element in our society, economy and environmental system.They cover over 70% of the worlds surface and contribute substantially to ecosystemservices such as climate management as well as to economic sectors such as foodproduction and tourism. While the importance of the oceans for climate changeand the society is generally acknowledged in science and literature, it is often notreflected in policy. Integrated Assessment Models (IAMs) which are used to advicepolicy on carbon prices often systematically omit process and damages related tothe ocean such as ocean acidification, loss of biodiversity and changes in oceancurrents.The aim of this study is to give a more detailed perspective on ocean related processesand their role and importance for the economy under climate change and to testassumptions made in the development of IAMs - and more precisely the DynamicIntegrated Climate-Economy model also referred to as the DICE model. The initialresults of the DICE model resulted in a optimal temperature trajectory with amaximum of 4 ◦C contradicting the goals set with the Paris Agreement.This thesis is the first of its kind attempt in reviewing the most recentbiophysical evidence on climate change impacts with a focus on marine systemsand incorporating these damages to market and non-market sectors into the DICEmodel. The impacts from climate change are implemented into the DICE modelthrough economic valuation of the damages and an update of the damage function.The analysis is based on the damage function used in the original DICE2016R2model as well as the suggested update presented by Hänsel et al. (2020)The results show, that incorporating marine damages into the model yields in amajor increase in economic damages particularly in the temperature range up to 2◦C.These increased damages influence the results of the optimal temperature trajectoryand give a clear indication for a more stringent climate policy, drastically limitingthe maximum temperature increase compared to the original DICE model. / Haven är en viktig del av vårt samhälle, vår ekonomi och vårt miljösystem. De täcker över 70 % av jordens yta och bidrar väsentligt till ekosystemtjänster ekosystemtjänster som klimatstyrning samt till ekonomiska sektorer som livsmedels livsmedelsproduktion och turism. Havens betydelse för klimatförändringarna och samhället och samhället är allmänt erkänd inom vetenskap och litteratur, återspeglas den ofta inteåterspeglas ofta inte i politiken. Integrerade utvärderingsmodeller (IAM) som används för att geom koldioxidpriser utelämnar ofta systematiskt processer och skador relaterade tillhavet, t.ex. havsförsurning, förlust av biologisk mångfald och förändringar ihavsströmmar.Syftet med denna studie är att ge ett mer detaljerat perspektiv på havsrelaterade processeroch deras roll och betydelse för ekonomin under klimatförändringen samt att testaantaganden som gjorts i utvecklingen av IAM - och mer exakt den dynamiskaintegrerade klimat-ekonomimodellen, även kallad DICE-modellen. De förstaresultaten av DICE-modellen resulterade i en optimal temperaturbana med ettmaximalt 4 ◦C, vilket strider mot de mål som satts upp i Parisavtalet.Denna avhandling är den första i sitt slag som granskar de senastebiofysiska bevis på klimatförändringens effekter med fokus på marina systemoch införliva dessa skador på marknads- och icke-marknadssektorer i DICEmodellen. Effekterna av klimatförändringarna implementeras i DICE-modellengenom ekonomisk värdering av skadorna och en uppdatering av skadefunktionen.Analysen baseras på den skadefunktion som används i den ursprungliga DICE2016R2modellen samt den föreslagna uppdateringen som presenteras av Hänsel et al. (2020)Resultaten visar att införandet av marina skador i modellen leder till enstor ökning av de ekonomiska skadorna, särskilt i temperaturintervallet upp till 2◦C.Dessa ökade skador påverkar resultaten av den optimala temperaturbananoch ger en tydlig indikation på en mer stringent klimatpolitik, som drastiskt begränsarden maximala temperaturökningen jämfört med den ursprungliga DICE-modellen.

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