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1.
Exurban areas have increasingly become zones of conflict as conservation and development compete for the same finite land resources. Conversion of natural areas to land dominated by human use results in loss, degradation, and fragmentation of wildlife habitat which often lead to species endangerment or even extinction. Recently, reserve site selection models have begun to integrate spatial attributes in order to design more compact and connected reserve networks that are thought to improve long-term species persistence. While these models are a good step forward to designing conservation reserve networks, they might not be adequate for use in exurban areas that consist of heterogeneous mosaics of land uses where habitat fragmentation already exists and not all parcels are available for preservation. This paper presents a species conservation framework that expands upon traditional reserve site selection models in three ways. First, because of the focus on exurban areas, the framework used here allows for land conversion within core habitat patches. Second, the framework provides a more robust assessment of connectivity among patches by accounting for land-use heterogeneity in the dispersal matrix. And third, the framework explicitly incorporates species population dynamics. We apply our conservation framework to the case of pond-breeding salamanders in an exurban community in Rhode Island, USA. Comparisons are made between the outcomes for uniform conservation policies and more flexible policies that accommodate ecological and economic heterogeneity. As expected, policies that offer more flexibility in the decision-making process are less costly in terms of foregone development. Conservation planners should consider core habitat patches, dispersal matrix, and spatial scale in their decision making. By not assessing the potential impact of dispersal barriers, reserve site selection models will result in conservation plans that may not protect species over the long term, particularly for species residing in highly fragmented landscapes such as those found in many exurban communities.  相似文献   

2.
We consider a broad class of linear dynamic stochastic rational-expectations models made of a finite number N of structural equations for N+1 endogenous variables and to be closed by one policy feedback rule. We design, for any model of this class and any stationary VARMA solution of that model, a “bubble-free” policy feedback rule ensuring that this solution is not only the unique stationary solution of the closed model, but also its unique solution. We apply these results to locally linearisable models of the monetary transmission mechanism and obtain interest-rate rules that not only ensure the local determinacy of the targeted equilibrium in the neighbourhood of the steady state considered, but also prevent the economy from gradually leaving this neighbourhood.  相似文献   

3.
Remote agricultural lands, which include wildlife habitat, angling opportunities and scenic vistas, command higher prices per hectare in Wyoming than those whose landscape is dominated by agricultural production. Geographic information systems (GIS) data are used to measure recreational and scenic amenities associated with rural land. A hedonic price model is specified with GIS measures. It is used to estimate the impact of amenity and agricultural production land characteristics on price per acre for a sample of Wyoming agricultural parcels. Results indicate that the specification performed well across several functional forms. The sampled land prices are explained by the level of both environmental amenities as well as production attributes. Statistically significant amenity variables included scenic view, elk habitat, sport fishery productivity and distance to town. This analysis permits a better estimation of environmental amenity values from hedonic techniques. Improved estimation of amenity values is vital for policies aimed at open space preservation, using agricultural conservation easements and land use conflict resolution.  相似文献   

4.
This paper discusses the estimation of parameters of a traditional transportation model, as it is typically present in so-called Takayama–Judge type spatial price equilibrium models. In contrast to previously used estimation methods, observations of regional prices as well as of trade costs are used in a direct estimation of the first order conditions. The proposed method uses bi-level programming techniques to minimize a weighted least squares criterion under the restriction that the estimated parameters satisfy the Kuhn–Tucker conditions for an optimal solution of the transport model. A penalty function and a smooth reformulation are used to iteratively approximate the complementary slackness conditions. Monte-Carlo simulations are used to trace out some properties of the estimator and compare it with a traditional calibration method. The analysis shows that the proposed technique estimates prices as well as trade costs more precisely than the traditional calibration method. It is suggested to apply the same method to a range of linear and quadratic models.  相似文献   

5.
This paper analyzes the effects of providing environmental amenities associated with open space in a discrete-space urban model and characterizes optimal provision of open space across a metropolitan area. The discrete-space model assumes distinct neighborhoods in which developable land is homogeneous within a neighborhood but heterogeneous across neighborhoods. Open space provides environmental amenities within the neighborhood it is located and may provide amenities in other neighborhoods (amenity spillover). We solve for equilibrium under various assumptions about amenity spillover effects and transportation costs in both open-city (with in- and out-migration) and closed-city (fixed population) versions of the model. Increasing open space tends to increase equilibrium housing density and price within a neighborhood. In an open-city model, open space provision also increases housing density and price in other neighborhoods if there is an amenity spillover effect. In a closed-city model, housing density and prices in other neighborhoods can decrease if the pull of the local amenity value is stronger than the push from reduced availability of developable land. We use numerical simulation to solve for the optimal pattern of open space in two examples: a simple symmetric case and a simulation based on the Twin Cities Metropolitan Area, Minnesota, USA. With no amenity spillover, it is optimal to provide the same amount of open space in all neighborhoods regardless of transportation cost. With amenity spillover effects and relatively high transportation cost, it is optimal to provide open space in a greenbelt at the edge of the city. With low transportation cost, open space is provided throughout the city with the exception of neighborhoods on the periphery of the city, where the majority of the population lives. A greenbelt still occurs but its location is inside the city.  相似文献   

6.
7.
Block factor methods offer an attractive approach to forecasting with many predictors. These extract the information in these predictors into factors reflecting different blocks of variables (e.g. a price block, a housing block, a financial block, etc.). However, a forecasting model which simply includes all blocks as predictors risks being over-parameterized. Thus, it is desirable to use a methodology which allows for different parsimonious forecasting models to hold at different points in time. In this paper, we use dynamic model averaging and dynamic model selection to achieve this goal. These methods automatically alter the weights attached to different forecasting models as evidence comes in about which has forecast well in the recent past. In an empirical study involving forecasting output growth and inflation using 139 UK monthly time series variables, we find that the set of predictors changes substantially over time. Furthermore, our results show that dynamic model averaging and model selection can greatly improve forecast performance relative to traditional forecasting methods.  相似文献   

8.
In models in which convergence in income levels across closed countries is driven by faster accumulation of a productive factor in the poorer countries, opening these countries to trade can stop convergence and even cause divergence. We make this point using a dynamic Heckscher–Ohlin model—a combination of a static two-good, two-factor Heckscher–Ohlin trade model and a two-sector growth model—with infinitely lived consumers where international borrowing and lending are not permitted. We obtain two main results: First, countries that differ only in their initial endowments of capital per worker may converge or diverge in income levels over time, depending on the elasticity of substitution between traded goods. Divergence can occur for parameter values that would imply convergence in a world of closed economies and vice versa. Second, factor price equalization in a given period does not imply factor price equalization in future periods.  相似文献   

9.
The expansion of nature reserves is an important public policy strategy for the protection of biological diversity. In this paper, the authors use integer programming model structures derived from Location Set Covering Problem and Maximal Covering Location Problem approaches of location science as tools for selectively augmenting nature reserve sites for special status species protection. The linear programming models presented incorporate the following: biological constraints in the form of species' area needs; economic constraints in the form of opportunity costs of converting smaller administrative districts into nature reserves; and spatial constraints in the form of required connectivity among districts in site selection. The construction of a taxonomic data set for Thailand enables the implementation of the models, the comparison of results and evaluation of the differences in outcomes. The models build upon the existing nature reserve network in Thailand and suggest various public policy options that would augment the reserves for enhancing species protection and for possibly improving national conservation efforts at lowest costs.  相似文献   

10.
This paper analyzes the dynamic interaction between two regions with interconnected river basins. Precipitation is higher in one river-basin while water productivity is higher in the other. Water transfer increases productivity in the recipient basin, but may cause environmental damage in the donor basin. The recipient faces a trade-off between paying the price of the water transfer, or investing in alternative water supplies to achieve a higher usable water capacity. We analyze the design of this transfer using a dynamic modeling approach, which relies on non-cooperative game theory, and compare solutions with different information structures (Nash open-loop, Nash feedback, and Stackelberg) with the social optimum. We first assume that the equilibrium between supply and demand determines the optimal transfer price and amount. We show that, contrary to the static case, in a realistic dynamic setting in which the recipient uses a feedback information structure the social optimum will not emerge as the equilibrium solution. We then study different leadership situations in the water market and observe that the transfer amount decreases toward a long-run value lower than the transfer under perfect competition, which in turn lays below the social optimum. In consequence, the water in the donor's river-basin river converges to a better quality in the presence of market power. Finally, we numerically compare our results to the Tagus-Segura water transfer described in Ballestero (2004). Welfare gains are compared for the different scenarios. We show that in all dynamic settings, the long-run transfer amount is lower than in Ballestero's static model. Further, we show that the long-run price settles at a lower level than in Ballestero's model, but is still higher than the average cost-based price determined by the Spanish government.  相似文献   

11.
We examine the interaction between asset market and current account in a small open economy. In an overlapping generations economy in which land and money are available assets, the interaction between the land price and current account dynamics is shown to generate a plausible (asset price) specie-flow mechanism. We apply them to a number of issues. Domestic credit policy is neutral in the long run: one unit of foreign reserve increase offsets one unit of credit reduction. Next, the association between the endowment of land and foreign asset accumulation depends on parameters of the model. Finally, we examine the dynamic adjustment s following a once-and-for-all capital inflow. When the adjustment involves running current account deficit, the recipient country's foreign reserve position is permanently lowered. Furthermore, the steady state level of national wealth is permanently reduced. [E4, F3]  相似文献   

12.
Cournot establishes a Nash equilibrium to a duopoly game under output competition; Bertrand finds a different Nash equilibrium under price competition. Both treat the strategic choice variable (output versus price) and the timing of play as exogenous. We investigate Cournot‐Bertrand models where one firm competes in output and the other competes in price in both static and dynamic settings. We also develop a general model where both the timing of play and the strategic choice variables are endogenous. Consistent with the conduct of Honda and Scion, we show that Cournot‐Bertrand behaviour can be a Nash equilibrium outcome.  相似文献   

13.
We show that incentive efficient allocations in economies with adverse selection and moral hazard problems can be determined as optimal solutions to a linear programming problem and we use duality theory to obtain a complete characterization of the optima. Our dual analysis identifies welfare effects associated with the incentives of the agents to truthfully reveal their private information. Because these welfare effects may generate non-convexities, incentive efficient allocations may involve randomization. Other properties of incentive efficient allocations are also derived.  相似文献   

14.
城市扩展中的土地价格变化:动态模型的考察及启示   总被引:1,自引:0,他引:1  
本文借鉴有关理论,构建城市土地租金与价格随城市扩展而变化的动态模型,分析了静态模型下与动态模型下的城市土地租金与价格的不同构成,以及城市扩展进程中土地租金与价格的变动趋势,并应用理论模型对成都市城市化进程中的部分重要问题进行了探讨。  相似文献   

15.
The highly disputed effects of agricultural trade liberalisation are mostly simulated with static models. Our main objective in this paper is to evaluate the robustness of the static simulation results to the consistent modelling of dynamic behaviours and to the linked specification of price/return expectations. Focusing on the scenario of a complete trade liberalisation of arable crop markets by developed countries, we find that available static results are quite robust compared to dynamic specifications and to most expectation schemes. Endogenous market fluctuations due to expectation errors may appear following trade liberalisation. These fluctuations are nevertheless limited by the many feedback effects revealed by our general equilibrium framework.  相似文献   

16.
This paper extends probit recession forecasting models by incorporating various recession risk factors and using the advanced dynamic probit modeling approaches. The proposed risk factors include financial market expectations of a gloomy economic outlook, credit or liquidity risks in the general economy, the risks of negative wealth effects resulting from the bursting of asset price bubbles, and signs of deteriorating macroeconomic fundamentals. The model specifications include three different dynamic probit models and the standard static model. The out-of-sample analysis suggests that the four probit models with the proposed risk factors can generate more accurate forecasts for the duration of recessions than the conventional static models with only yield spread and equity price index as the predictors. Among the four probit models, the dynamic and dynamic autoregressive probit models outperform the static and autoregressive models in terms of predicting the recession duration. With respect to forecasting the business cycle turning points, the static probit model is as good as the dynamic probit models by being able to flag an early warning signal of a recession.  相似文献   

17.
This paper estimates a forward-looking life-cycle model of outmigration and labor force participation. The estimated model is used to evaluate the impact of enforcing a maximum stay duration for newly admitted immigrants on labor force participation and outmigration. Restricting the migration duration is found to have little effect on the labor force participation of skilled immigrants, and a negative effect on that of unskilled immigrants. Restricting the migration duration is also found to encourage the departure of unskilled and unsuccessful immigrants before the maximum duration is reached. These results are obtained by estimating the model with data that contain no information on outmigration decisions. It is shown that the assumption of a continuous state variable affecting attrition only through outmigration allows the probability of outmigration to be identified from the panel attrition. This probability can then be estimated using standard dynamic programming techniques. The migration durations so estimated are found to differ substantially from those estimated under the assumption that immigrants are myopic decision makers.  相似文献   

18.
In auctions where a seller can post a reserve price but if the object fails to sell cannot commit never to attempt to resell it, revenue equivalence between repeated first price and second price auctions without commitment results. When the time between auctions goes to zero, seller expected revenues converge to those of a static auction with no reserve price. With many bidders, the seller equilibrium reserve price approaches the reserve price in an optimal static auction. An auction in which the simple equilibrium reserve price policy of the seller mirrors a policy commonly used by many auctioneers is computed.Journal of Economic LiteratureClassification Numbers: C78, D44, D82.  相似文献   

19.
This paper considers three-dimensional panel data models with unobservable multiple interactive effects, which are potentially correlated with the covariates. We propose an iterated OLS (IOLS) approach for the estimation of the static model and an iterated GMM (IGMM) method for the dynamic model. Monte Carlo simulations illustrate that our methods perform well in finite samples.  相似文献   

20.
Actual property values are overwhelmingly employed as a dependent variable in hedonic pricing models. Yet, assessed property values are generally more readily available than actual sales values and have, in some studies, been used in lieu of market prices. In this study, we compare estimates of different non-market amenity values based on actual transactions and assessed values. We estimate a Seemingly Unrelated Regression (SUR) model with two hedonic price equations, one with actual market values as the dependent variable and the other with assessed property values, and compare the resulting estimates of shadow prices for open space amenities. We also take into account spatial autocorrelation and combine Method of Moment estimates of the spatial parameters in both equations to create our test statistic. The results indicate that we cannot accept the hypothesis that the impacts of open space on property values are the same for actual sales and assessed values. Moreover, we do observe some differences between the distributions of assessed versus sales values, although the difference between the sizes of open space effects measured within the two equations is rather limited. Thus, while this one study is insufficient to enable one to draw definitive conclusions, there remains the possibility that policy makers cannot reliably base decisions on amenity values obtained from a hedonic model using assessed values.  相似文献   

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