In Brazil, economic data on fisheries are generally scarce, and difficult to interpret with respect to costs and fishery viability, thus making it difficult to practice consistent policy and industrial decision-making. This thesis aims to provide a cost-benefit analysis of seventeen commercial fishing fleets that operated during 2013-2014 in four port regions of the South Brazil Shelf: Angra dos Reis (AR), Santos and Guarujá (SG), Itajaí and Navegantes (IN) and Rio Grande (RG). The fleet types included the following: shrimp-trawlers, pair-bottom-trawlers, single-bottom-trawlers, bottom-gillnetters, octopus-pots, purse-seiners, surface-longliners and pole-and-line. Based on an unprecedented set of field survey data collected through interviews with vessel captains and owners, this study has the following goals: (1) to describe, calculate and compare the cost structure and gross profitability for all fleets; (2) to identify the factors (e.g., technical features and economic indicators) that determine fleet gross profit (from AR, SG and IN) using generalized additive models (GAMLSS); and (3) to assess the net profitability and viability of the fleets through the following three economic performance indicators: net profit margin (NPM), net present value (NPV) and internal rate of return (IRR). Additionally, the effects of fuel subsidy policies on profitability among South Brazil\'s fleets were evaluated. Generally, operational costs were higher than labor and fixed costs except for longliners, purse-seiners (from AR) and bottom-gillnetters (from RG), whereas labor costs were higher or had the same importance as operational costs. Fuel was the primary operational cost for all the fleets except pair-bottom-trawlers (SG) and purse-seiners (AR), for which vessel maintenance is the principal operational cost. Gross profitability varied significantly among the fleets and was clearly related to the following main factors: fuel consumption, vessel maintenance expense, ice costs, fish price and catch volume. Particularly for trawlers (from SG and IN) and all purse-seiners, technical features (i.e., vessel size and number of fishing trips, respectively) also explained profitability. Moreover, landing cost was a significant factor for those fleets\' profit. Economic performance indicators exhibited intra-fleet heterogeneity depending on region and revealed that 24% of the fleets were unviable (NPV less than zero), 23% were in fragile condition (IRRs and NPM lower than 11%), and 53% had achieved good economic returns whose IRR values exceeded 12% and whose NPM was > 10%. The worst economic performance was observed for single-bottom-trawlers (RG) and purse-seiners (SG) and the best for tuna-longliners (RG) and pair-bottom-trawlers (SG). Overall, subsidies were ineffective in increasing Rio Grande fleet profits and may be masking poor economic performance, primarily for single-bottom-trawlers (RG). Findings should guide private-sector decisions on how to protect the economic performance of the fleets, on fishery management measures (e.g., input controls, recovery plans for overfished stocks), and improve current governmental programs (e.g. the fuel subsidy program). / No Brasil, os dados econômicos sobre as pescarias são geralmente escassos, dificultando o conhecimento sobre os custos e a viabilidade da pesca, tornando difícil a prática de tomada de decisões políticas consistentes. Esta tese tem como objetivo fornecer uma análise de custo-benefício de dezessete frotas de pesca comercial que operaram durante 2013-2014 em quatro regiões da Plataforma Continental Sul do Brasil: Angra dos Reis (AR), Santos e Guarujá (SG), Itajaí e Navegantes (IN) e Rio Grande (RG). Os tipos de frotas analisadas foram: arrasto de fundo duplo (camarões), parelhas, arrasto de fundo simples, emalhe de fundo, pesca de potes (polvo), traineiras, espinhel de superfície e pesca com vara-e-isca-viva. Com base em um conjunto sem precedentes de dados de pesquisa de campo coletados através de entrevistas com mestres e proprietários de barcos pesqueiros, este estudo teve como objetivo: (1) descrever, calcular e comparar a estrutura de custos e a lucratividade bruta das frotas; (2) identificar os fatores (características técnicas e indicadores econômicos) que determinam o lucro bruto das frotas (de AR, SG e IN) usando modelos aditivos generalizados (GAMLSS); e (3) avaliar a lucratividade e a rentabilidade líquida, e a viabilidade das frotas por meio dos seguintes indicadores de desempenho econômico: margem de lucro líquido (NPM), valor presente líquido (NPV) e taxa de retorno interno (IRR). Além disso, os efeitos da política de subsídio ao combustível sobre a rentabilidade das frotas do sul do Brasil foram avaliados. Geralmente, os custos operacionais foram maiores que os custos de mão-de-obra e custos fixos, exceto para as frotas de espinhel de superfície, traineiras (de AR) e emalhe de fundo (de RG), onde os custos de mão-de-obra foram maiores ou tiveram a mesma importância que os custos operacionais. O combustível foi o principal custo operacional para todas as frotas, exceto para as parelhas (SG) e as traineiras (AR), para os quais a manutenção do barco foi o principal custo operacional. O lucro bruto variou significativamente entre as frotas e esteve relacionada aos seguintes fatores: consumo de combustível, despesas de manutenção de embarcações, custos com gelo, preço do peixe e volume de captura. Particularmente para as frotas de arrasto de fundo (de SG e IN), parelhas (SG) e traineira, as características técnicas (ou seja, tamanho da embarcação e número de viagens de pesca, respectivamente) também explicaram a lucratividade. Além disso, o custo com o desembarque foi um fator significativo para o lucro dessas frotas. Os indicadores de desempenho econômico apresentaram heterogeneidade intra-frota dependendo da região e revelaram que 24% das frotas estavam inviáveis (NPV inferior a zero), 23% estavam em vulnerabilidade (IRRs e NPM inferiores a 11%) e 53% alcançaram bons retornos econômicos cujos valores de IRR excederam 12% e o NPM foi > 10%. O pior desempenho econômico foi observado para as frotas de arrasto-simples de RG e para as traineiras de SG, e os melhores para os atuneiros (RG) e parelhas (SG). Em geral, os subsídios foram ineficazes no aumento dos lucros das frotas de Rio Grande e podem estar mascarando o baixo desempenho econômico, principalmente para a frota de arrasto-simples. Os resultados apresentados podem ser utilizados para orientar nas decisões do setor privado sobre como proteger o desempenho econômico das frotas, as medidas de manejo da pesca (por exemplo, controles de entrada, planos de manejo para recuperação dos estoques sobrepescados), e ainda melhorar os programas governamentais atuais (por exemplo, o programa de subsídio ao combustível).

[Truncated abstract] Removal of consumers through fishing has been shown to influence ecosystem structure and function by changing the biomass and composition of organisms occupying lower trophic levels. The western rock lobster (Panurilus cygnus), an abundant consumer along the temperate west coast of Australia, forms the basis of Australia's largest single species fishery, with catches frequently exceeding 11000 tonnes annually. Despite their high abundance and commercial importance, the diet and trophic role of adult lobster populations in deep-coastal-ecosystems (35-60 m) remains unknown. An understanding of the diet and trophic role of lobsters in these ecosystems is a key component of the assessment of ecosystem effects of the western rock lobster fishery. This study uses gut content and stable isotope analyses to determine the diet and trophic role of lobsters in deep-coastal ecosystems. Dietary analysis indicated adult lobsters in deep-coastal ecosystems were primarily carnivorous with diet reflecting food available on the benthos. Gut content analyses indicate crabs (62 %) and amphipods/isopods (~10 %) are the most important lobster dietary sources. Stable isotope analysis indicates natural diet of lobsters in deep coastal ecosystems is dominated by amphipods/isopods (contributing up to ~50 %) and crabs (to ~75 %), with bivalves/gastropods, red algae and sponges of lesser importance (<10 % of diet each). Diet of lobsters in deep-coastal ecosystems differed from that reported for lobsters inhabiting shallow water ecosystems in this region, reflecting differences in food availability and food choice between these ecosystems. Bait from the fishery was also determined (by stable isotope analyses) to be a significant dietary component of lobsters in deep-coastal ecosystems, contributing between 10 and 80 % of lobster food requirements at some study locations. '...' Given observed effects of organic matter addition in trawl fisheries, and also associated with aquaculture, bait addition is likely to have implications for processes occurring within deep-coastal ecosystems in this region, particularly given its oligotrophic status, most likely by increasing the food available to scavenging species. Removal of lobsters from deep-coastal ecosystems may affect the composition and abundance of lobster prey communities through a reduction in predation pressure. Such effects have been demonstrated for other spiny lobster species. These effects are typically most observable amongst common prey taxa which in other studies have been commonly herbivores. In deep-coastal ecosystems, crabs and amphipods/isopods are the most common prey taxa and most likely to be effected. The ecosystem-impacts of top-down control of non-herbivorous prey species is unknown and constrains the inferences possible from this study. However, the establishment of 'no-take' areas in deep-coastal ecosystems would allow the ecosystem effects of lobster removal to be further assessed in these deep-coastal ecosystems. While data from the current study did not allow the ecosystem effects of lobster removal to be properly assessed, this study provided information regarding the ecology of western rock lobsters in previously unstudied ecosystems.

本論文旨在探討非營利組織及其捐贈者所享受的租稅優惠，是否應依組織性質的不同而有所差異。本研究參考相關文獻及美國內地稅法的分類方式，將國內非營利組織依公益性質及商業性質劃分為六類，並寄發問卷詢問國內會計師、營利事業財務主管及負責人、非營利組織管理者及負責人、學者及稅務人員對此六類組織及其捐贈者享受各項免稅優惠的贊同程度。本研究以敘述統計、t檢定及一般線性模式等統計分析方法對文獻探討所建立的假說進行測試，得出下列實證結果： 一、各界對於非營利組織及捐贈者享受免稅優惠的贊同程度，依組織公益性質的不同而有顯著的差異。公益程度愈高者，各界贊成免稅的程度愈高。 二、各界對於非營利組織及捐贈者享受免稅優惠的贊同程度，依組織商業性質的不同而有顯著的差異。各界對不具商業性質的組織有較高的免稅贊同度。 三、各界對於非營利組織及其捐贈者享受租稅減免優惠的贊同度，因減免項目的不同而有顯著的差異。 四、各界對於捐贈者享受所得稅或遺贈稅扣除優惠的贊同程度高於非營利組織本身享受各稅減免的贊同程度。 五、非營利組織管理者對於組織本身享受所得稅、營業稅、關稅及財產稅免稅優惠的贊同度顯著高於其他受試者。 經過文獻探討、各國免稅規定之比較及實證結果分析之後，本文重要的結論與建議如下： 一、鑒於公益性組織與互益性組織在所得稅上享受相同的租稅優惠，建議修改免稅適用標準，比照英美的做法將非營利組織依公益性質有系統的劃分為二至三類，並依組織公益性質的不同給予不同程度的租稅優惠。例如：對私人基金會的投資所得課徵特種稅(excise tax)；個人或企業對互益性組織的捐贈行為應享受較少的所得稅及遺產及贈與稅之免稅優惠。 二、建議恢復部分非營利組織銷售行為免稅的規定，可參酌英國、美國、新加坡及德國的稅法規定，將免稅範圍限制於符合免稅目的或慈善目的之銷售行為，或給予具商業性質的組織及其捐款者較低程度的免稅優惠。 / This study classifies the nonprofit organizations in Taiwan into six categories in terms of the degree of their public and business characteristics. The subjects are asked to express their opinion to the tax exemption of these six kinds of the nonprofit organizations. The subjects include the scholars, the certified public accountants, the managers and executive officers of the nonprofit organizations and the business companies, and the tax collectors of the tax authority. Descriptive statistics, t tests, and GLM are applied to analyze the responses of the subjects. The following results are obtained: 1. The subjects' agreement to the tax exemption of the nonprofit and its donators are significantly influenced by the degree of public for the organizations. The higher the degree of public for the organizations, the higher the subjects' agreement. 2. The subjects' agreement to the tax exemption of the nonprofit and its donators are significantly influenced by the degree of business for the organizations. The subjects have higher agreement to the tax exemption of the non-commercial organizations. 3. The subjects' agreement to the tax exemption of the nonprofit and its donators are significantly different between the different taxes. 4. The subjects' agreement to the tax deduction for donation is higher than the agreement to the tax exemption for NPO. 5. The managers of the nonprofit organizations have higher agreement to the tax exemption of the nonprofit than other subjects. After analyzing the responses of the subjects and comparing the tax laws of several countries, we provide following proposals to revise the tax laws. 1. The nonprofit need to be systematically classified according to the public characteristics and treated differently. For example, the investment income of the private foundations needs to be taxed for excise tax; donators of the mutual organizations should be benefited less by the deduction of the income tax and estate tax. 2. The tax exemption of the sales conduct of some nonprofit organizations should be retained but subjected to the organizations whose conduct conforms to the charitable or exempt purposes. Besides, the commercial organizations should be benefited less by the tax exemptions.

農業發展曾經在臺灣的經濟建設史上，佔有輝煌一頁，民國四十至五十年代，農民胼手胝足地配合政府農業政策，不只增裕農業生產，同時也奠定臺灣日後工商發展之基礎，然而隨著臺灣經濟的發展，工商業產值佔GDP比例加重，農業產值佔GDP比例卻逐年下降，農業經營也面臨許多難題及衝擊，農戶所得水準相對非農戶為低，老年農民生活保障不足等問題一再被提出討論，同時由於近年來農業生產不符經濟效益等因素，且部分農民福利措施對農民資格的界定迭起社會爭議，因此各項保障農民福利措施的公平性及必要性亦隨之引起爭論，本文試著從農民的社會保險、老年給付、租稅福利、價格補貼及其它救（補）助措施等五方面，來探討農民的福利保障現況，並針對現況缺失提出檢討與建議，尤其面對全球經濟自由化趨勢下，如何協助農業經營轉型，增進農民福利，應是農民、農業部門及政府需共同思索的問題。 / The prosperity of agriculture played an important role in Taiwan’s economical construction history. In 1940’s and 50’s, Taiwan’s farmers, actively responding to the agriculture-developing policy, not only increased the agricultural production, but also helped to establish a firm foundation for the following industrial and commercial development in Taiwan. However, as the industrial and commercial value increases yearly in GDP, the value of agriculture in GDP, on the other hand, decreases year after year. Farmers thus faced many problems and challenges. Issues such as the obvious poorer condition of farmers’ life compared to the non-farmer, and the unsatisfying welfare state of retired farmers are frequently among the arguments. Furthermore, owing to the facts that most farmers own some real estates as the grounds they plant and yet their production can’t even reach the bottom line of economical effect, the necessity and justification of farmers welfare measures are consequently evoking constant controversy. The goal of this thesis, therefore, is trying to examine the status of Taiwan’s farmers’ welfare state in the following five fields: farmer’s social insurance, elderly farmer’s allowance, tax welfare, price subsidy and other assistance measures, and to raise my proposals and suggestions to solve these problems. How to help farmers to do well in the transformation of agricultural management and thus improve their welfare state should be a public issue for farmers themselves and the agriculture departments as well as the whole government, especially when facing the trend of liberalization of the global economics.

本研究所要探討的課題主要有以下三點：1.現行國宅等候制度有何缺失？應如何改進？2.我們由台灣省各縣市等候名冊申請登記戶數情形可以看出，目前國宅需求集中在政府直接興建國宅，而輔助人民貸款自購住宅之需求則相對較少，其背後原因為何？應如何改進？3.各縣市國宅資源是否真的不足？目前以供給面的政府直接興建國宅為主的住宅補貼措施是否適當？應如何改進？ 　　為針對以上問題加以解答，本研究首先以國宅等候制度在實際執行上所應發揮的三項功能：掌握國宅需求、決定國宅資源分配順序與提供人民充分資訊為觀點，對現行國宅等候制度加以檢討，最後並對我國國宅等候制度未來的改進方向提出具體的建議。 　　其次，本文以國宅需求量本身之決定因素（資格、意願、負擔能力）作為研究基礎，以臺灣省21縣市為實證範圍，估計歷年國宅需求量，進而探討影響國宅需求量變動的各種因素，特別強調不同補貼額度對國宅需求量的影響，透過計量經濟分析方法，最後驗證了補貼額度與國宅供給速率對於國宅需求量確實存在有顯著的影響。 　　最後，本研究以資源公平效率分配的觀點，配合國宅供需現況，以模擬分析的方式對臺灣省二十一縣市的國宅資源分配加以試算，結果發現，各縣市國宅供需失衡之主要原因不在國宅資源不足，而是在資源分配之不當，若將供給面補貼的政府直接興建國宅資源部分分配到需求面補貼的輔助人民貸款自購住宅，大部份縣市均能在短期內解決其國宅供需失衡問題，且可有多餘的資源用於增加如出租國宅、租金補貼、售屋不售地國宅及特殊弱勢團體住宅等國宅產品。 / There are three main subjects that we want to explore in this study: 1.What problems exist in the public housing waiting system in Taiwan? 2.What reasons cause the demand of public housing much more than the demand of mortgage subsidy in Taiwan? How will we improve it? 3.Is the housing subsidy policy in Taiwan moderate? How will we improve it? 　　To solve the above problems, we first review merits and demerits of the public housing waiting system. We examine three practical functions of the public housing waiting system. One is having the demand of public housing in hand, the one is deciding the order of public housing allocation, and the other one is providing sufficient information to people. From the review, we suggest the directions to improve the public housing waiting system. 　　Second, based on the factors of demand to the public housing (capacity、 willing、 afford ability), we applied regression analysis on the 21-Taiwan-county data. The regression model shows the main factors are the amount of housing allowance and the speed of public housing construction. 　　Finally, with the view of justice and efficiency on the resource allocation of housing subsidy, we simulate the resource distribution of public housing subsidy in the 21-Taiwan-county. We ascertain the main factor of public housing disequilibrium is inappropriate resource allocation. Have we transferred the resource from the public housing for selling to the mortgage subsidy, most counties could solve the disequilibrium problem in short run. In the long run,there are more resources to increase the supply side.These extra-resources serve the public rental housing, rental subsidy and welfare public housing etc..

農業是人類最基本的經濟活動。儘管隨著科技及社會的發達，農業在一國的總產值或就業人口所佔比例逐漸降低，然而在國際貿易的舞台上，農業貿易的重要性卻不減反增。世界貿易組織（World Trade Organization, 簡稱WTO）之杜哈發展議程（Doha Development Round, DDA）曾一度中止的原因即為各國之間對於農業貿易存在極大的分歧，尤其歐洲聯盟（European Union，簡稱歐盟） 的「共同農業政策」（Common Agricultural Policy,簡稱CAP）更是備受爭議。歐盟共同農業政策係指歐盟為其農業發展所實施包括農產品價格支持、最低保證收購價格、對歐盟境外產品實施關稅及配額等相關補貼制度。「共同農業政策」所以深具爭議，主要在於其對農業有補貼或境內支持政策造成對貿易不公與市場扭曲現象，尤其以農產品出口為大宗的發展中國家受害最深。因此，在多次談判回合中，歐盟共同農業政策常常為其他WTO會員國所詬病。在WTO逐漸成為各國無法忽視的規範力量，以及各國與歐盟的農產品貿易爭端層出不窮之下，歐盟行之有年的「共同農業政策」面臨重大調整。 / Agriculture is the basic economic activities of human beings. Though the relative size of agricultural sector has been declining as the society and technology develop, the importance of agriculture in the international trade is still growing. The Doha Development Round of the World Trade Organization had once suspended because of agriculture negotiations, on which WTO member countries could not reach agreements. Among them, the Common Agricultural Policy (CAP) of the European Union is the most controversial. The Common Agricultural Policy combines a direct subsidy payment for crops and land which may be cultivated with price support mechanisms, including guaranteed minimum prices, import tariffs and quotas on certain goods from outside the EU. The reason why CAP is so controversial is for its high amounts on agricultural subsidies and domestic support, which amount to unfair competition and market distortion. In this regards, CAP damaged the interests of agricultural exporting country, especial those developing countries. Thus CAP had always been criticized by other WTO members in the WTO agriculture negotiation. Since WTO has become the dominant regime of international trade, and there are more and more agricultural disputes arising between EU and other WTO members, EU has to undertake substantial reform on CAP.

2008年底源自於美國信貸市場的金融風暴席捲全球，影響層面襲擊實體經濟，無論在投資、消費、產出與貿易上都出現驟降的表現，世界經濟遭逢二次大戰以來最嚴重的衰退，勞動市場同樣受到嚴重的打擊，不過，因為年齡、性別、教育程度等條件的差異，不同群體所承受的就業風險也不盡相同。面對百年罕見的經濟危機，青年因先天上存在著缺乏技術、工作經驗、社會網絡、求職知識、經濟支持等劣勢，無疑成為景氣動盪下受衝擊最大的族體。 台灣青年在就業市場上的艱困處境，在金融海嘯的侵襲下更顯艱難。比較經濟危機的發生前後，青年失業率增漲達3.84％，高於全體失業率的漲幅1.94％，而2009年青年的平均失業率是全體平均失業率5.85％的2.48倍。其中值得注意的是，在青年失業者中，大專及以上學歷的人數為15萬1千人、佔55.73％，高居各教育程度之冠。政府為消除金融風暴下大專青年進入職場的障礙，於2009年4月推出「大專畢業生至企業職場實習方案」，補助企業聘僱員工時的薪資與社會保險等人事成本，短期目標是平衡勞動市場供需，長期則是期待透過實習經驗提升實習員的就業能力，達成促進就業的治理目的。 本研究擬針對教育部所規劃推動的「大專畢業生至企業職場實習方案」作為分析對象，其係屬積極勞動市場政策下針對雇主的薪資補貼政策，已在OECD國家行之有年，無論在推動經驗或評估報告上，都累積十分豐碩的資源，可作為後進國家之政策制訂者與研究者的參考依據。因此，在擬定寫作策略上，先行回顧各國曾經施行的方案制度和評估報告，緊接著整理我國近年相關的薪資補貼政策的制度差異，以作為分析「大專畢業生至企業職場實習方案」的基礎工作。最後，在「大專畢業生至企業職場實習方案」的成效評估上，採取積極勞動市場政策評估中的「績效檢視」與「過程評估」，透過質量並重之研究途徑，以問卷調查的研究方法以檢視企業職場實習方案之實習者離開方案後的再就業成效，同時為彌補量化取徑之限制與理解政策執行面，佐以深度訪談來獲得在研究主題上更寬廣的理解。

行動上網技術的成熟，為行動上網市場提供了良好的發展環境，吾人認為第三代行動通信業者的行動上網定價模式也扮演了關鍵的催化劑角色。 本研究主要是探討台灣第三代行動通信業者在訂定行動上網服務定價模式時，對於內、外部因素的考量，並進一步了解其現有定價模式與內、外部考量因素的關聯性，以期能為行動上網服務定價模式找到新的方向。 本研究之研究問題有三: 1. 影響3G營運商行動上網服務定價模式之主要因素為何? 2. 3G營運商在訂定行動上網服務定價模式的主要考量因素為何? 3. 3G營運商行動上網服務現有定價模式的訂定與考量因素的關聯性為何? 本研究透過深度訪談與相關的次級資料蒐集與彙整分析後，獲得以下六個結論。 1.用戶數成長、營收成長、網路建設成本還有手機補貼是影響電信公司行動上網服務定價模式的內部因素。 2.寡占市場結構與回應競爭者是影響電信公司行動上網服務定價模式的外部因素。 3.用戶數成長還有營收成長是所有電信公司訂定定價模式時的主要的考量因素。 4.為了回應競爭者並與市場競爭，所有電信公司都是以單一費率定價模式搭配手機補貼來行銷行動上網。 5.兩段式與預付型定價模式是為了要達到提高用戶數成長的公司目標。 6.產品組合定價模式是為了要達成提高非語音營收成長的公司目標。

Cross-boundary movements of energy and material are ubiquitous. Freshwater ecosystems receive nutrients, dissolved, and particulate organic matter from adjacent terrestrial ecosystems, whereas terrestrial ecosystems mainly receive prey organisms and detritus deposited by physical processes such as floods from freshwater ecosystems. Within lakes, fish are considered as integrators between habitats due to their high mobility, although they often occupy either near-shore littoral or open-water pelagic habitats and develop habitat-specific morphologies. Such intra-population divergence in morphological traits might limit the use of multiple habitats. In this thesis, I first focused on quantity and quality of reciprocal fluxes of particulate organic matter between freshwater and terrestrial ecosystems and responses of recipient consumers. Freshwater ecosystems generally received higher amounts of externally-produced resources than terrestrial ecosystems. Despite this discrepancy, aquatic and terrestrial consumer responses were similar, likely due to the differences in resource quality. Second, I investigated the potential of particulate organic carbon (POC) supporting benthic food webs in lakes; a pathway that has largely been neglected in previous studies. I found that POC can substantially subsidize the benthic food web and that the effects on the benthic food web were transferred to the pelagic habitat, thus emphasizing the importance of benthic pathways for pelagic production. Third, I examined how water transparency can affect intra-population divergence in perch (Perca fluviatilis). I observed that increased water transparency can considerably increase morphological divergence between littoral and pelagic populations likely due to its effects on foraging. Finally, I investigated the effects of such intra-population divergence on littoral-pelagic food web coupling. I found that low morphological divergence corresponded with high overlap in resource use, whereas strong morphological divergence resulted in low overlap in resource use. Here littoral populations mainly utilized littoral resources and pelagic populations primarily utilized pelagic resources, indicating that habitat coupling might be strongly limited when intra-population divergence is high. In conclusion, although different ecosystems seem separated by distinct physical boundaries, these boundaries are often crossed. However, the development of habitat-specific adaptive traits might limit movement between apparently contiguous habitats.

Da diversi anni la letteratura economica raccomanda l'utilizzo del road pricing come strumento efficiente per internalizzare le esternalità (ambientali e di congestione) prodotte dalla circolazione dei veicoli sulle strade. Tuttavia, l'accettabilità di questo strumento è in genere molto bassa. Pertanto, il lavoro di ricerca svolto è stato indirizzato allo studio di uno schema di road pricing più accettabile, giungendo alla elaborazione di una politica innovativa, il charge-subsidy road pricing (CSRP). Il CSRP prevede che gli automobilisti ricevano gratuitamente un certo numero di permessi che consente loro di guidare in un'area soggetta a pricing nelle ore in cui è in richiesto il pagamento. Inoltre, il CSRP consente a coloro che hanno bisogno di un numero maggiore di permessi di comprarne di aggiuntivi dentro pagamento di una charge; allo stesso tempo lo schema prevede che coloro che riescono a risparmiare parte dei permessi ricevuti possano restituirli e ottenere in cambio un beneficio (monetario/fiscale o in natura ) dall'amministrazione incaricata di gestire il sistema. L'idea di fondo che sta dietro il CSRP è il fatto che la distribuzione gratuita di un certo numero di permessi dovrebbe rendere il CSRP più accettabile di altre politiche di road pricing più tradizionali: il lavoro svolto testa questa ipotesi sia da un punto di vista teorico che empirico. / Economists tend to support road pricing for its efficiency properties in tackling road usage externalities (in particular, congestion and environmental impacts), but usually the acceptability of this instrument is really low both among the general public and politicians. Thus, this PhD research is an attempt to design and analyse a more acceptable road pricing scheme, i.e. a charge-subsidy road pricing scheme (CSRP) where car owners are allotted an amount of free units they can use in place of money to pay for the kind of road pricing scheme implemented. Under the CSRP those who want to drive more than the allowance provided are required to pay a charge, while a (monetary/fiscal or in kind) subsidy might be given to those who manage to spare some of the initially distributed rights. The presence of an initial amount of free units should make the CSRP more acceptable than other traditional road pricing schemes: indeed this work investigates this hypothesis by means of a theoretical and an empirical analysis.