François Bonnieux

Robert D Weaver

Managing Agriculture's Impacts on the Environment: Basic Economies and International Evidence

Introduction

ESAs represent a policy mechanism aimed at inducing changes in economic activity to increase social welfare. The value of the ESA mechanism results from the net social benefits it induces. lt follows that estimation of the benefits of ESA applications must be grounded on an understanding of the change in economic activity that the application hopes to induce, the changes in economic goods that result, and the sources of social value of those changes in available goods. Most generally, ESAs can be viewed as a mechanism for inducing changes in current and future environmental performance. Authors have presented varied definitions of the goals of ESAs, however, the primitive concept that can be extracted from each of these definitions is that of change in environmental performance. More specifically, the environment of interest is the nonurban, land related environment. In the U .K. this environment has been labeled countryside, while in the U.S. literature the term landscape has taken on a generalized connotation.

A rather limited literature has considered the public economics of the ESA mechanism in general, or of estimation of the benefits associated with particular applications of ESAs. [START_REF] Colman | Comparative Effectiveness of Conservation Mechanisms[END_REF] and [START_REF] Colman | Comparative Evaluation of Environmental Policies, ESAs in a Po licy Context[END_REF] present a useful description of alternative conservation instruments and an assessment of their relative effectiveness based on a menu of criteria ( e.g. capacity to protect and enhance, timeliness, targetability, monitorability, cost efficiency, political acceptability and transparency, promotion of conservation-mindedness). [START_REF] Bateman | Research methods for valuing environmental benefits[END_REF] and Willis and Garrod ( 1994) present brief considerations of the microeconomics of benefit measurement and more thorough overviews of alternative approaches. However, in each case, these presentations are limited to considerations of the traditional case of benefits attributable to provision of a public good. In the case of ESAs, the linkage between a program and public good provision is obscured by both the complexity of programs as well as numerous types of uncertainty of program effects. Further, the intended economic effects of ESAs often go beyond provision of public goods to include management of extemalities and private provision of public bads.

The objective of this paper will be to reconsider the valuation of ESAs at both a conceptual level and to reassess available evidence of benefits generated by ESAs within this context. The next section reconsiders the origins of social value induced by ESA mechanisms.

In so doing, the section considers the character of the economic goods that might result from use of the ESA mechanism, the mechanism through which the supply of these goods is induced, and the bases of social value of these goods might generate. Next, the microeconomics of valuation of these goods is reconsidered graphically and conclusions are drawn conceming what frameworks are appropriate for general application. The fourth section presents an assessment of available evidence concerning the value of particular ESA applications. Finally, conclusions are drawn.

ESAs as a Mechanism that lnduces Increased Social Value

The objectives of the ESA approach has been popularly understood to be the safeguarding of particular characteristics (landscape, wildlife, and historical features) of rural land through the management of agriculture's role in the landscape, Willis et al. (1993). The concept emerged in the 1980s in response to public concern over two types of agriculture outputs: 1) extemalities associated with intensive agriculture and their effects on the rural landscape and 2) perceived beneficial effects of Jess intensive, traditional agriculture and its role as a distinctive and valued element in rural landscapes. Traditional agriculture was perceived to contribute to preservation of valued landscapes ( e.g. meadows, grasslands, heathers, etc.); landscape functions such as wildlife habitat provision; to reduced off-site effects through hydrologie stabilization, windbreaks that reduce soi! displacement, etc.; and to preservation of archaeological and architectural features. In this sense, these beneficial effects were generically classified as public goods, although economists would classifiy them more precisely.

The notion of an ESA was introduced in European Community law within the context of agri-environment schemes which could be adopted on a voluntary basis by member states, [START_REF] Beaufoy | Impact of the CAP Reform on Land Use and Rural Amenities[END_REF], Whitby and Lowe (1994). Importantly, it emerged as a result of public recognition and valuation of the extensive variety of nonmarket economic goods or services produced by agricultural land use. In the U.K., ESA legislation emerged under Section 18 of the Agricultural Act of 1986 and lead to five ESAs being designated in 1987, six in 1988, six in 1993, and six in 1994, Willis et al. (1993, p.5), Whitby and Lowe (1994). During the first rounds, farmers were offered fixed period contracts providing annual fixed payments in return for adoption of a set of farm production practices. These practices involved requirements as well as prohibitions on daily and seasonal activities with a focus on chemical application, stocking densities, infrastructure installation such as drainage or fencing, and management of landscape features. Often, these practices were adopted as part of an overall plan for the farm.

Payments were based on area treated by the practice or prescription. Adoption rates have been high and shown steady growth in the U.K.

In France, ESA applications were initiated between 1991 and 1993. In 1993, ESA applications were brought under European Community initiative (CEE 2078/92). As in the U.K., the areas of application were spatially limited, however, the French applications involved more extensive negotiation with farmers of the terms of the contracts to offered in each area. French applications focused on two goals: 1) ex situ preservation of biodiversity or specific biotopes (30 ESAs by 1993 encompassing about 220,700 ha with about 83,700 ha enrolled) and 2) preservation of extensive agriculture and reduction of land abandon.ment in areas of traditional, yet highly dispersed agriculture (24 ESAs by 1993 encompassing about 509,000 ha of which only about 115,800 ha was eligible for financing). The second goal was intended to protect natural areas from abandonrnent or encroachment of more intensive uses.

In total these two goals involved only about 700,000 ha of which only 205,000 ha were eligible for participation (i.e. farmed land). The budgetary commitment was 92.5 million FF.

A small number of ESA were initiated, though later abandoned, which were focused on water pollution and fire protection in forested pasture. Implementation led to a substantially smaller number of ESAs due to administrative delay, or under enrollment and closure. Despite farm representation in the contract specifications, participation was low, CNASEA ( 1992).

Most recently, the agri-environrnental regulation (2078/92) established a package of measures which are mandatory for ail states to implement through zonal programs in their territories. Rather than limiting these schemes to particular areas, their zonal focus would allow them to be available to ail areas within the territory with such zonal characteristics.

Each of these programs offers standard payments to farmers to take actions which produce public goods and reduce externalities. These actions are intended to simultaneously maintain agricultural land use while shifting agricultural practices toward those that benefit the environment. Under the regulation, member states presented proposais for such zonal programs. The details of these new applications have been reviewed by other papers presented in the volume.

Throughout the historical evolution of ESAs, political and social debate has obscured the underlying public economics of ESAs. We next review these foundations to clarify the origins and characteristics of changes in social value they might induce. Accepting the focus of ESAs on altering the performance of the rural environment or countryside, we begin by reconsidering the nature of performance with which are concerned. Most typically cited as the target of ESAs are changes in externalities and environmental outputs produced by agriculture, [START_REF] Crabtree | Effectiveness of Standard Payments for Environmental Protection and Enhancement. Actes du 30èmc séminaire de l'Association Européenne des Economistes Agricoles[END_REF], Whitby and Lowe (1994). This definition can been extended to include changes in the production of negative public goods, i.e. _public bads, such as generation of CO 2 and ozone destruction or habitat destruction and displacement. Within a temporal sense, this list of performance goals appears to focus on contemporaneous effects. However, it is clear from most discussion of ESAs that their intent is to alter the intertemporal effects of agriculture on the environment. In this sense, the rural environment is viewed as dynamic system and the objective of public management is to divert that system from its current or future paths associated with purely private decisions to a path which is viewed as having greater social value. lt is within this sense that ESAs encompass goals such as improvement of habitat, stimulation of wild species, or elimination of invasive species.

The focus of ESAs is on agriculture. Within the rural setting, man's impacts occur through agriculture, forestry, recreation, resource extraction, and infrastructure installation and use (e.g. highways, dams, etc.). Agriculture is the predominant occupation of rural land and, therefore, dominant as an economic activity through which man affects nature. Therefore, it is natural that agriculture was targeted as a basis for affecting the value of nature. Further, agriculture involves active management of the rural landscape. Numerous analyses of ESAs present commentary on the role that post-war period intensification (chemical use, varietal homogenization, more frequent cropping) and expansion (drainage, grassland conversion) of agricultural activities have played in altering the nonmarket goods supplied by such activity, e.g. [START_REF] Froud | Upland Moorland with Complex Property Rights, The Case of the North Peak[END_REF]), O'Carroll (1994), [START_REF] Saunders | Single-Tier System with Many Farms Partly Outside the ESA, The Case of the Pennine Dales[END_REF]), Coleman et al. (1994).

We next consider the mechanism through which ESAs operate. Here, we depart from the literature to focus on the economically operative elements of the mechanisms. We define the ESA mechanism as involving standardized contracts to purchase changes in agricultural production practices (by requirement or prohibition) affecting land through payment systems.

They are offered to farmers within a targeted subset of the population. Until recently, targeting was accomplished on a geographical basis imposing spatial limits based on specific environmentally sensitive areas allowing targeting of the contracted group of providers, the ecological and other physical characteristics of the environment affected, and the beneficiaries of the public good or reduction of the externality. In the PAC reform, the basis for targeting was redefined to include land or ecological characteristics, or zone types.

Most generally conceived, an ESA represents a social contracting scheme which purchases changes in production practices which are hoped to induce private provision of public goods, reduction of public bads and reduction in externalities from private owners of rural land. Weaver (1994) presents an economic theory of environmental effort by farmers which clarifies the need for such social contracting. In brief, Weaver notes that where farmers hold nonhedonistic preferences, a contracting approach can encourage private voluntary contribution in a way which is not possible using traditional Pigouvian instruments such as regulatory standards or incentives such as penalties or taxes. Despite the fact that the ESA mechanism is a contractual purchase arrangement it is centrally directed and typical applications have offered homogenous standards and incentives to heterogeneous populations of farmers. In ail past applications, the mechanism has operated indirectly in the sense that contracts are for private good production practices which are predicted to result in production of desired public goods or reduction in externalities or public bads. Often the contracted production practices may produce joint multiple outputs or effects. The contracts have involved restriction of production practices either by prohibiting use of particular activities which are perceived to result in public bads or externalities or by requiring use of activities that are perceived to result in public goods production.

From this perspective, Crabtree (1993) and others have questioned whether the ESA mechanism can be interpreted as a property rights transfer mechanism. For this paper, it is of interest to ask whether such an interpretation provides a useful basis for valuation of ESA applications. Crabtree (1993) properly noted that the ESA mechanism involves a restriction of the production possibilities set available to farmers. Whitby (1989) adds the additional presumption that the farmers hold a property right to freely choose production practices.

Based on this presumption, ESA mechanisms which impose restrictions on production practices can be viewed as involving a transfer of property rights from the former to society in return for a cash payment. The cash payment can then be interpreted as equal to or greater than the former's valuation of that property right. This perspective would seem appropriate for contracts which prevent the former from using practices or taking specific actions which produce public bads, or externalities. For the case of contracts for production of public goods, [START_REF] Crabtree | Effectiveness of Standard Payments for Environmental Protection and Enhancement. Actes du 30èmc séminaire de l'Association Européenne des Economistes Agricoles[END_REF] concluded the property right transfer interpretation is less useful. In this case, the contract represents a purchase of private provision of a public good. Where contracting is for direct provision of a public good, the contract can be viewed as providing direct incentives for a particular output and no property rights transfer is implicit. In contrast, where public goods are only indirectly contracted, e.g. by contracting only for the use particular production practices which are perceived to result in production of the desired public good, a property right transfer interpretation would appear to remain useful. As a basis for valuing ESA applications, the property right transfer interpretation provides a basis by which the ESA value could be viewed as based on social valuation of ownership of the right. That is, social value would indicate society's valuation of the former not having the right to pursue particular production activities. However, from a practical standpoint, because this right is at best only indirectly linked to the reduced production of an externality or public bad, or increased production of a public good, this type of property right provides a very limited basis for establishing value of an ESA application.

The ESA mechanism applications have also allowed for more direct contracting for the provision of public goods. For example, the European Community legislation clearly recognizes formers as having the potential to produce environmental goods through their direct management of the countryside. For example, farmers can privately invest to produce various landscape elements such as woodlands or wetlands, or landscape characteristics such as wildlife through introduction of species (see [START_REF] Crabtree | Economie Evaluation of the Farm Woodland Scheme[END_REF]. In these cases, property rights transfers are not involved, and instead foirly traditional production economics suffice to analysis the supply of these goods through acceptance of contracts. From the perspective of valuation, provision of these public goods will typically involve marginal changes in the aggregate supply allowing marginal valuation. In many cases, however, valuation will be complicated by the fact that the goods are not pure public goods, but rather may involve some aspects of limited access, at least in a spatial sense.

Given that ESA mechanisms can be interpreted as contracting mechanisms, it is useful to clarify the extent to which they are interpretable as management agreements. [START_REF] Colman | Comparative Effectiveness of Conservation Mechanisms[END_REF] define management agreements based on their historical application in the U.K. In this case, they are defined as individually negotiated contracts between a public agency and a land owner to restrict or initiate land management activities. They classify ESA mechanisms as standard payment systems in which contracted practices and payments are the same across participating farmers. Here, our intent is not to confuse the literature, but to distinguish among the operative elements of the ESA mechanisms. Clearly, they involve contracting for private management either restricting or requiring particular practices.

To summarize, several features of the ESA approach are important to note: l) it may involve either indirect or direct provision of public goods, reduction in public bads and externalities, often these outputs are multiple and jointly produced (along with other public as well as with private outputs) by particular environmental efforts of the farmer, 2) it allows targeting in a variety of dimensions, 3) it relies on voluntary participation by farmers, 4) it involves contracts with standard payments as incentives and standard management agreements as regulatory constraints across participants.

The specific characteristics of particular ESA applications can now be placed within the context of this more general set of characteristics. Specific applications of ESAs have been reviewed by [START_REF] Willis | The Value of Agricultural Landscapes in England and Wales: a case study of the Yorkshire Dales[END_REF], [START_REF] Merlo | Public Benefits valuation in ltaly: a Review of Forestry and Farming Applications[END_REF], Riera (1994), Dubgaard (1994) (in Dubgaard, 1994), [START_REF] Moss | A Basel ine Assessment for a New ESA[END_REF]), Fraud(1994), O'Carroll (1994), [START_REF] Saunders | Single-Tier System with Many Farms Partly Outside the ESA, The Case of the Pennine Dales[END_REF], Coleman et al. (1994), Hughes, (1994) all in Whitby( 1994); Willis et al. (1993), Coleman et al. (1992), Todd (1993), andBonnieux, et al. (1993). Each of these applications involved multiple standard management agreements and standard payments which farmers choose from a menu of available option. Thus, while the general mechanism is uniform across applications, the composition of the menu offered in terms of contracted or restricted production activities varies widely as do the perceived public goods, bads, or externalities that are the objective of the contract. In practice, the objectives of each ESA and the expected effects or outputs necessarily varies depending on the character of the demand for and potential supply of its public characteristics. Applications reported in Whitby (1994) illustrate this variation as well as the variation of participation and choice of menu elements across the heterogeous farm population.

A review of the possible nonmarket goods induced by ESAs highlights the variety of types of public outputs expected from these programs. Outputs include pure public goods such as preservation habitat diversity to encourage speciation to congestible, spatially limited quasi-public goods such as landscape use in hunting, viewing, or exercising. Importantly, the outputs are often multiple and jointly produced by the farmer's environmental effort. For example, actions taken by the farmer to enhance the visual amenities of the farm site will typically alter habitat inducing long term benefits related to changes in biodiversity and shorter term benefits related to wildlife use activities ( e.g. hunting, viewing, etc.). Outputs also vary in the extent to which they generate utilitarian vs. nonutilitarian benefits, the length of the horizon over which these benefits will be generated, the uncertainty with which they will be generated, the dynamic path of supply associated with the goods or their characteristics, as well as their jointness in supply and/or demand or benefit characteristics.

Finally, the interaction of these goods or outputs with private goods or services also varies substantially.

The Origins of Social Value Created by ESA Applications

The origin of social value that ESA mechanisms hope to create lies ultimately on the value that humankind places on nature. ESA mechanisms hope to create a change in the environmental performance of the rural landscape. In this sense, they attempt to affect marginal changes in the current and future state of nature. Operatively, ESA mechanisms affect nature through standard management agreements. While the ESA designation of an area may have some impact independently of any effect produced through changes in management, the basis of such changes is unclear. Here, we consider only changes induced through standard management agreements. At the most general level, the notion that nature has value is complex, Kim and Weaver(l 994). lt is clear, however, that across cultures and time humans have placed value on nature. Within this context, nature has been understood to mean ail things not created by man. The value of nature has been extensively considered within a number of disciplines. Economists have focused on utilitarian value, Weaver (1994). While other disciplines have recognized nonutilitarian values associated with nature, [START_REF] Norton | Biodiversity and Landscapes, A paradox ofhumanity[END_REF], Rolston (1994), Katz (1994). Utilitarian value can be decomposed into direct consumption value, option value, and existence value. Nonutilitarian value systems necessarily go beyond homocentric perspectives that view nature as an entity that serves humankind, [START_REF] Hargrove | The paradox of humanity: two views of biodiversity and landscapes[END_REF], Weaver and Kim (1994 ). Within this taxonomy, it is clear from the list of environmental effects or outputs expected from past ESA applications that the social value of these effects or outputs may involve all elements of this taxonomy.

Based on the characteristics of the ESA mechanism as well as the diversity of economic goods its application is hoped to induce, the challenge of valuation of a particular ESA application is striking. While the challenges of valuing landscapes have often been noted ( e.g. Weaver and Kim(l 994), Price (1994)), their consideration has often been limited to the problem of valuing a particular known change. In the context of ESA applications, numerous types of environemental efforts are implemented, which are hoped to induce a diversity of public goods, bads, and changes in extemalities. Thus, the valuation problem must necessarily consider a vector of changes. While the jointness in production of these outputs has been noted, their consumption my also be joint. Focusing on single output effects, [START_REF] Bateman | Research methods for valuing environmental benefits[END_REF], [START_REF] Merlo | Public Benefits valuation in ltaly: a Review of Forestry and Farming Applications[END_REF] among others have presented reviews of valuation approaches that may be useful. However, these reviews consider only valuation of known changes in a particular public good. As was argued in the previous section, the problem of valuation of a particular ESA application is considerably more complicated. To simplify, while highlighting this complexity, suppose an ESA application produces a single public good, however, suppose we allow it to have characteristics the suppl y of which is dependent on I) uncertain participation by farmers, 2) uncertain efficiency of farmers production, and 3) uncertain technological feasibility; and where they may be said to be characteristics 1) with utilitarian value, 2) with nonutilitarian value, 3) with uncertain current value, 4) with uncertain future value, 5) with pure public good aspects, 6) with spatially limited access aspects, 7) which substitute with some private goods, and 8) which complement other private or public goods.

The problem of valuation must necessarily involve 1) valuation of different types of goods,

2) valuation over different horizon, 3) valuation under different extents of uncertainty, 4) valuation based on different approaches, and 5) aggregation of these heterogeneous sources of value, possibly recognizing complementarity in demand. Given this complexity, the necessity of treating each output of an ESA application is clear. Coleman et al. (1993), Willis et al (1993) provide illustrations of such individualized treatment.

At this point, we are in a position to consider an obvious question: What are the implications of this complexity for comparative assessment of value across applications? To suppose comparative assessment is of interest requires that the same change is made across applications. The complexity of the ESA mechanism and its variation across applications implies that such a common change does not exist, in general. Even where the same practice is restricted in a set of applications, the output goals and effects may be different. Where the same goal or output effect can be found, comparative value assessment might be feasible.

However, such feasibility would rel y on independence of that output from others produced by the applications, unless those other outputs are also identical across applications. Where such independence does not exist, comparison would be difficult. Consider an example. Suppose in two applications the public good output of improved visual value of the landscape is sought and attempted by field perimeter plantings of poplar trees. Suppose in both applications, intensive field cropping occurs, however, assume in application A cold winters imply substantial wind induced soi! erosion occurs while in application B, such erosion does not occur. To compare the visual value of the treatment across the two applications would clearly require identification of the value of the erosion protection and air quality services in application B. While this example is sufficiently simple to suggest that such evaluation would be possible, typical ESA applications involve a large number of outputs and interacting practices.

Valuation of When Public and Private Outputs are Joint

Before moving to consider and interpret available evidence of the value of ESA applications, we present an economic framework which clarifies many of the complications already discussed. In particular, the problem of valuation of the public good is extended to consider the case where it is jointly produced with private goods, as is the case in ESA applications. Consider the simple case where the ESA application results in a vector of public goods (e.g. ecological and amenity) and a vector of private goods (agricultural outputs). We would like to determine the value of public goods, i.e. the social rate of exchange or trade been the public and private benefits generated. Define social welfare U as a function of a vector of public goods Q and a vector of private agricultural commodities X :

1) u = u(x,Q).
Define the product transformation function that bounds the set of all technologically feasible combinations (x, Q) following Weaver and Harper (1993):

2) c(x, Q; z,e )= o
where Z is a vector of environmental inputs and 0 is a vector of quasi-fixed, private inputs

The social choice problem is to find a feasible combination (x•, Q.) which maximizes social welfare 1) subject to available technology described by 2). Graphically, the solution of the problem illustrated in Figure 1 by A. which lies at the tangency of the isosocial welfare curve U* and the production possibilities frontier G*. At the tangency, the exchange rate defined in terms of social welfare (marginal rate of social welfare substitution MRSWS) between the goods is set equal to the exchange rate between the goods defined by technology (marginal rate of tehnical transformation MRTT) between the goods. Stated differently, the rate at which society is willing to trade Q for Xis set equal to the rate at which society can actually trade Q for X as defined by technology.

The problem of valuation is clear from Figure 1 and the character ofthis tangency. For market goods, prices serve as signais to which consumption and production adjust to establish the conditions at point A*. Where prices do not exist, we seek alternative means of evaluating the exchange rates of Q for X defined at point A*. The first conclusion that is apparent from this simple graphie and the logic of economic optimization is that when prices are not available, it is more difficult to determine the position of A*. What we need in terms of valuation is not simply a value at A*, instead we need sufficient information to help us find A*. In terms of the graphies of Figure 1, what we need are estimates of how the exchange rates MRSWS and MRTT change as Q and X are changed. Suppose point Q' were offered to consumers. The value of point Q' could be established by standard methods of valuation. One approach would be to measure the willingness of society to exchange Q for X (MRSWS) along U', a lower level of welfare, finding MRSWS' < MRTT' signaling that a reduction of Q and an increase in X would increase social welfare. From another perspective, consider a change in the environment from Q* to Q', i.e. such that l:!..Q > 0 . In Figure 1, M 1 measures the amount of X society would be willing to pay have Q' stay at the same utility level U* as before the change in Q. Alternatively, M 2 indicates how much X would have to be paid to allow Q' to be technologically feasible.

Under standard curvature properties shown in Figure 1, M 1 < M 2 which implies society would not be willing to pay as much as technology would demand be paid for an increase in Q from Q* to Q'. Conversely, the same logic could be applied for a decrease in Q from Q' to Q*.

In this case, society would be willing to give up Q at a rate that exceeded that which is demanded by technology and the adjustment to Q* would be welfare increasing. Finally, in Figure 1, ôR defines the amount of X that a market, if one were operative in both goods, would demand be accepted for a decrease from Q' to Q*. Figure 2 presents the same logic for the case where an increase in Q is optimal. Initially Q equals Q" , and M 2 < l:!..R < M 1 as Q" < Q • . Using the same logic as was applied to Figure 1, it is clear that welfare can be increased by increasing

Q 0 to Q • . Figure 2.
Finally, the same logic can be applied to when Q denotes a public bad as described in Figure 3. Here, free disposai is not assumed for the public bad. To consider hedonic price estimation approaches, Figure 1-3 are also useful. For example, in Figure 1, the slope of line P* indicates the relative prices of X and Q, i.e. P*= P* Q/P*x where the asterisk indicate prices at the social welfare optimum A*. Hedonic approaches attempt to estimate PQ at the observed set of goods. However, where no markets are available to force P to P* and goods to A* , there is no basis for determining the relative prices and hedonic approaches are infeasible. In Figure 1, when the line P* is not defined relative to the slopes of G and U* at A* ; no basis exists for fixing its position and its slope is indeterminant. Where an implicit market exists for Q, hedonic methods can be used to estimate the implicit price P Q• For example, the use of a rural setting could be estimated from prices of leisure homes in the setting, Willis and Garrod (1993).

Valuation of Rural Landscape Amenities

Given the conclusion that the value of ESA applications is best based on valuation of each of multiple and possibly joint public effects which are the goals of the application, we now provide a review of available evidence concerning the value of one of the most typically expected products of ESA applications: rural landscape amenities. Severa! studies have been conducted in which the value of agricultural landscape was estimated by means of contingent valuation. In comparison with CV studies in the field of recreation, application of CVM to rural amenities is more subject to misspecification of the product. In particular, geographical part-whole bias and policy-package part-whole bias are likely to result from inadequate specification of the amenity. Geographical part-whole bias occurs when a respondent values a landscape whose spatial attributes are larger or smaller than the spatial attributes of the researcher's intended landscape. There exists empirical evidence that people are able to discriminate a local landscape from a national landscape. Thus, specification of the geographical scope of the amenity is essential. Consider a respondent who is asked how much he is willing to pay for maintaining today's landscape in an ESA. If the respondent is unable to isolate that area in his mind from a larger area covering the specific ESA, the respondent may in fact value a larger area than intended by the researcher. Policy-package part-whole bias occurs where a respondent values a broader or a narrower policy package than the one intended by the researcher. This issue is of particular importance within the context of ESAs.

Given that agricultural activities and particular ESA applications can produce a wide variety of public effects which may be associated with both current and future time periods, the precise nature of the public effect to be valued by respondents must be specified. Where this has not be accomplished, response can not be associated with particular public effects and in the extreme, may be based on a vague and poorly specified notion of the en tire menu of public goods supplied by agriculture. In the context of the Common agricultural policy reform, people may treat the ESA scheme as symbolic of a larger policy goals (e.g. preservation of farming as a way of life) and assign to the scheme some of the values they have for this more general goal.

Table 1 gives a sample of studies whose objective is to value the preservation of today's landscape. Studies covering very limited portions of land such as specific habitats or sites of scientific interest (SSis) are not included. First, the challenge of comparison of results from various ESA applications is clear. No only does methodology differ across studies, but studies rarely provide sufficient information to allow even the calculation willingness to pay in a common currency or measure.

Table 1.

As already noted, the particular policy package involved in each study differs and it is unclear how estimated values can be related to particular policy elements, or management practices. Drake (1986) considers WTP to maintain an open landscape in the whole Sweden whereas Le Goffe and Gerber (1994) and Dillman and Bregstrom (1991) address the landscape issue at a local level. Taking into account the average size of a Swedish household, Drake's figure is the highest and appears consistent with our expectations. However, no objective basis exists for validation of these estimates. Hackl and Pruckner (1994) estimated roughly a similar level of WTP for the provision of agricultural landscape cultivating services in Austria. Nonetheless, the context of their research is different since the countryside is considered an important input for the Austrian tourism service. The large difference in WTP estimates between the two other studies are attributable to the difference in local context. It is not easy to compare WTP across the other studies since some refer to the household and others to visits. Riera (1994) considers benefits of preserving a large area of high landscape quality in the Catalan Pyrénées and Rebolledo and Perez y Perez (1994). Consider a broader good which is the maintenance of a natural park close to the Aragon Pyrénées. While estimates from these studies appear consistent, a review of the literature shows a diversity of estimates. For example, [START_REF] Merlo | Public Benefits valuation in ltaly: a Review of Forestry and Farming Applications[END_REF] have reviewed Italian estimates of the public benefit values of forestry and farming areas and found a high degree of occurrence. This difference is due both to differences between sites and to differences in the way in which methods have been applied. The majority of benefits values range between 3 and 10 Ecu per person per visit. Bateman et al. (1992) in [START_REF] Willis | Valuation of the South Downs and Somerset Levels and Moors Environmentally Sensitive Area Landscapes by the General Public[END_REF] consider ESA's.

The first study refers to the Norfolk Broads which under threat from flooding whereas the second is based on the South Downs and the Somerset Levels and Moors. So differences in WTP could be attributable to differences in goods which are valued.

In our opinion a more important point has to be made: the value of a specific ESA is conditional on the continued protection and preservation of the other ESAs. So it can be assumed that the marginal benefits of an ESA decline as the number of ESAs increases. This implies that aggregate total benefit curves increase at a decreasing rate with the protection of additional areas. This issue was made clear in the context of the preservation of wild and scenic rivers in Colorado (Walsh et al., 1985) and has been taking into account by Willis, Garrod and Saunders in their investigations.

Table 2 provides aggregate values for several areas. The range of WTP per hectare is very large. The dispersion cannot be attributed to differences in unitary values. lt mainly cornes from the definition of the population concerned by the good. For the resident component things are quite clear. It is more difficult to delineate the visitor population specially for a fuzzy good such as landscape. Moreover we are confused regarding what are the good criteria to define the non-user category.

Table 2.

There is a limited number of hedonic price studies whose objective is to value landscape and countryside amenities. Two specific studies referring to the UK (Garrod and Willis, 1993) and France (Anonymous, 1994) aim be mentioned. The first study encompasses some 4 800 km 2 of central England and the Welsh borders and is concerned with the market of bouses in rural areas (the data base includes 2 000 observations). It is constrained by empirical data since the environmental data are neighborhood-specific rather than housespecific, relating to 1 km 2 in which the bouse is located. It was not possible to estimate the demand for particular countryside characteristics. The second study encompasses ail France and there are 3 300 observations, the dependent variable equals the rent for a vacation bouse ("gite rural"). It suffers the same limitations regarding environmental data as they are defined at the "Département" level. These variables include specific components of land use e.g. arable land, forest-land. So it is possible to infer the impact of various changes in land use on rents using the hedonic function. For example in a specific "Département" ("Manche") the increase in total rent would equal 45 F per hectare in response to the conversion of 1 000 hectares of arable land to permanent pasture.

Table 3.

bias, we note that the local vs. classic public good nature of effects will also involve what we label conceptual part-whole bias. That is, if respondents hold a conceptual basis for valuation that is not identified in the survey process, their response may follow from either local geographical or a local conceptual base. While geographical part-whole bias may be addressed through off-site surveys, the conceptual part-whole bias must also be addressed through specification of the effects of the ESA. Clearly, where the conceptual basis 1s unknown to the researcher, aggregation of individual benefit estimates will be problematic.

With respect to methods, it is clear from our analysis that contingent valuation approaches, though limited by the realm of complications we have discussed, remain preferable to hedonic or travel cost approaches. From the perspective of part-whole biases, it is clear that these latter approaches offer very limited opportunities for consideration of such biases. Nonetheless, our review provides a solid basis for the conclusion that the utility of CVM studies could be expanded by the adoption of common bases for their implementation bases for their implementation. Through such harmonization in approach and method the development of an expanding data base would be ensured as well as would an increased level of comparability across studies. For this reason, we recommend that effort be placed toward To provide at basis for comment on such questions, we see it as essential that guidelines be established to harmonize data collection and valuation approaches. In both cases, we do not support rigid standards, instead we propose the adoption of guidelines that ensure room for innovation while retaining a sufficient basis for comparative analysis. We propose that the bases for such harmonization be developed through a multinational effort that ensures the eventual convergence of approaches and confidence in results.

  Figure 1.

  Figure 3.

  such harmonization in both the valuation and in the design of ESA applications. Such harmonization, in our view, should be targeted at ensuring that an adequate base is developed to provide scientific comment on the following policy questions: 1) what is the level of net benefits generated by ESA applications? 2) to what extent do ESA applications? 2) to what extent are ESA instruments neutral in their affects on production decisions? and 3) what are implications of past ESA applications for future applications?

  Figure 1 -Valuation of a decrease in environmental goods

Table 1 . WTP for landscape and countryside according to geographical level

 1

	Author	Geographical level		WTP (1992 Ecu)
	Drake 1986	national		92/person/year
			resident	(16-74 years old)
	Bateman et al. (1992)	regional	visitor	95.3 -280.6/household/year
			non-user	5.1 /household/year
	Willis, Garrod and	regional	resident	22.0 -34.5/household/year
	Saunders (1993)		visitor	14.8 -24.4/household/year
			non-user	2.5 -3. l /household/year
	Riera (1994)	regional	user and existence value	6.5/visit
	Rebolledo and	regional	user and existence value	9.6/visit
	Perez y Perez ( 1994)
	Le Gaffe and	local	resident	60.6/household/year
	Gerber ( 1994)
	Dillman and	local	resident	6. 7 -l 0.5/household/year
	Bergstrom ( 1991)

Table 2 . Comparison of nature conservations estimates Table 3. WT A for changing farming practices -Ecu/ha/year

 2

	Substituting grassland for maize crops
	Reduction in stocking rate	-.25 GLU/ha
		-.50 GLU/ha
	Joining an organic farming network
	Source: Bonnieux and Rainelli, 1994.

Conclusions

The objective of this paper was to reconsider the public economics of the ESA mechanism and the valuation of the effects of ESA applications. At the core of the ESA mechanism lies a presumption that manipulation of private good production activities will affect environmental processes to generate a change in associated public good effects. This logic relies on the existence and nature of a relationship between private and public good production processes. Our first conclusion is drawn from our consideration of this relationship. As we noted, the technology of producing public effects through agricultural activities is one that involves three important characteristics: l) multiple private and public effect outputs which are often joint, 2) uncertainty due to randomness of environmental inputs, and 3) site specificity. With respect to the latter characteristic, it is important to note that scale, scope, biophysical, and manager characteristics are likely to be important. The immediate implication of these characteristics is that even if the ESA mechanism involved only one instrument, multiple interacting affects would be expected, implying that valuation must span the set of generated effects. Unfortunately, the ESA mechanism involves multiple instruments rendering the problem even more complicated. Because multiple effects are likely to be interactive, and because of the jointness of the underlying technology, it is unlikely that the effects of an individual instrument will be identifiable. The conclusion can, therefore, be drawn that valuation of ESA mechanisms must simultaneously consider the application of the entire package of instruments involved in the ESA and value the package of effects generated, including both private and public effects. Going one step deeper into a potential mire, it is interesting to note that since application of the package of instruments induces changes in production practices, the cost of an application is not temporally separable from the benefit stream as in many cases of public investment. It follows that valuation of effects ( i.e. ex post analysis) must be broadened beyond benefit analysis to include cost analysis as well.

A second conclusion can be drawn from the theoretical consideration of the ESA mechanism. In many cases, ESA applications will generate both local public goods which verge toward club goods for which exclusions are feasible, and, more classic public goods.

Consider the case of actions directed toward biodiversity. Maintenance or redevelopment of hedges can be expected to generate local public benefits in the form of aesthetics or use ( e.g. hunting) while at the same time generating a classic public good of biodiversity preservation.


Central and Eastern Europe have emerged from decades of centralised economic planning and political dictatorship and are moving towards democracy and a market economy. The great economic, social and political importance of the food-chain and the rural world in these countries means that they are particularly affected by cunent changes.

According to the country, agriculture employs between 1"0 and 277o of the working population, represents 7 to 2O7o of the gross national product ;25-647o of the population is of rural origin ; agricultural and food products contribute to L5-357o of exports. Moreover, the agricultural and food sector, one of the major areas of experimentation for the communist production model, had a specific structure and organisation resulting from this : collective ownership of land and means of production, industrialised agriculture, division of labour, vertical integration of the different activities of the food-chain... It is essential that higher education in agricultural and food sciences should undergo rapid adaptation, for three reasons :

-Like technical education and the training of engineers in general, it was strongly influenced under the previous regime by political pressure towards a certain type of organisation and operation, which was the condition for generosity in allocation of resources.

-The traditions and tasks of the food-chain, its specific character and that of the rural world, its institutional organisation into universities or faculties covering a wide range of disciplines (from social sciences to pure and applied sciences) make the agricultural sciences a key area for new thinking and the innovation of new types of training offering an integrated approach to economic, social and technical development.

-The agricultural sciences offer an interesting subject for analysis of the impact of economic and social transition on the adaptation of scientilic and technical education.

Science and technology are the results of a society's history, and the transmission of knowledge is strongly linked to social and political context.

This study examines the current transformations and principal areas of development in higher education in the agricultural and food sciences in Central and Eastern Europe. It draws on the authors' experience of these university systems acquired through the setting-up of joint projects, through numerous contacts with teachers and researchen and through consultancy missions carried out for the European Commission, particularly in POLAND, HUNGARY and RUMANIA. This is a western view of what must remain, in part, a reality foreign to our own experience. The more so, as that personal experience concerns teaching and researching in western, and more particularly French, institutions, given the specific character of French higher education (split between universities and "écoles d'ingénieurs").

a.

We shall first recall the general context of restructuring of higher education in these countries, then analyse the specific case of the agricultural sciences, and define priority areas for development in this type of education. We shall pay particular attention to long study couÉes (more than four years), which should be the point of departure for an overall reorganisation of studies in the field of agriculture.

The situation is obviously not identical from one country to another, but beyond national variations there exist strong common factors we wish to underline.

For convenience, we shall frequently use the term agricultural sciences to refer to the range of disciplines commonly taught at university level in this sector : the agricultural production sciences, including horticulture and forestry, food science and technology... II -THE GENERAL CONTEXT OF REFORM IN HIGHER EDUCATION Higher education in Central and Eastem Europe is the object of attention from international organisations (World Bank, European Union), Ministries and professionals, in an attempt to determine the conditions and characteristics of its short and long-term development. It is recognized (Commission des Communautés Européennes, L993) that higher education has a part to play in the reform of these countries.

Four missions have been defined for the university :

to facilitate the transition towards a market economy and the restructuring of different sectors of the economy through initial and continuing education producing a qualified workforce, adapted to the needs of the labour market, to participate in the overall renovation of education and training by producing competent and highly motivated teachers responsible for the education of new generations, to contribute to the evolution towards a pluralistic and democratic society. Beyond its activities of teaching and research, higher education has a role to play in socio-political changes. It acts as guardian and communicator of social values, contributes to social cohesion, political stability and the development of knowledge, and humanity.

to play a leading role in regional economic, social and cultural development.

ln the majority of these countries reforms are already under way in the legislative and institutional framework. All the governments concerned have begun work on the question and changes are under discussion or already in place, although education is rarely an immediate priority, and pressure of other business often causes delays.

The objectives are known : increase in the number of graduates to attain western levels; prevention of the brain drain (emigation from Central Europe, intemal movement towards more attractive or better paid professions, lack of interest in university careers among young people) ; development of the non-university sector.

The directions of development have been defined :

decentralisation and autonomy of the universities, improvement in system productivity and institution management, more democratic access, development of continuing education, diversification and flexibility of training, application of new teaching methods encouraging initiative, autonomy, synthesis and reasoning, aimed at decision-making, closer relations between teaching and research and an the end of to the split betrveen universities and Academies of Science, strengthened contacts befween teaching and industry, which provides both employment and funds for research and financing institutions, links between secondary and higher education... The dilficulties have been identified severe budgetary constraints which appear in poor maintenance of equipment and premises, lack of funds for modernisation and purchasing of teaching material, low salaries and purchasing power of academics and other staff, human problems caused by an ageing academic staff, poorly motivated and sometimes resistant to change, institutional problems arising from a hierarchical structure not disposed to call its own existence into question.

Given these circumstances, it is obviously useless to propose radical reforms which are highly unlikely to succeed : progress will only come from steady pressure for restructuring from the inside, relying on existing resources and finding means of motivating the different protagonists (students, teaching staff, administrators and economic partners). The limited public resources available make it essential that quality and efficiency should be priorities.

IIT -CRISIS IN THE TEACHING OF AGRICULTURAL AND FOOD SCIENCES :

Central and Eastern Europe possesses a considerable educational infrastructure, (Commission of the European Communities, L993 ; I.C.A., 1991) with over 40 universities teaching agricultural and food sciences, horticulture and forestry. They have an impressive student/teacher ratio (5-10 students per teacher) catering for high numbers of students (usually 3-5000 students per institution). Incal competence and experience in technical education and applied research are beyond question and well-known. This educational potential is currently experiencing problems of adaptation. The difficulties are frequently similar to those encountered in the whole of higher education, as we have stated. Nonetheless, they are particularly acute given the current economic, social and technical transformations in the food-chain.

These appear at different levels :

a fall in recruitment (also affecting some western universities), both in student numbers and in quality of candidates, affecting this area of education while competition is increasing in new university sectors (economic and social sciences, law...). The social origins of students contribute to this problem in that the majority (50-807o) come from a rural world currently in recession.

a decrease in employment, made worse by low professional mobility. In the past, as many as 607o graduates worked for large state farms or agricultural cooperatives. Highly qualified and technically specialised, they supervised the process of agricultural production and the transformation of products. The dismantling of these large organisations and the progressive appearance of smaller units of production is rapidly reducing an employment sector which was formerly large, protected and often state-controlled. However a new demand for other qualification profiles is emerging but is very often not yet financially viable (see below);

difficulty in meeting strong potential demand for continuing education and retraining of managers, given lack of structures, funding and organisation of the market; lack of specific competences, notably in new disciplines (law, management, economics, social sciences) but also in traditional subjects which have failed to keep pace with progress in science and research, and in those linked to new concepts (product quality, protection of the environment, land use management...) ; a training model poorly suited to the needs of the moment. Graduates with a high level of technical specialisation need to be replaced by multi-skilled design engineers with high professional mobility, trained in technical and economic management. The technical profile should become the responsibility of technical schools or colleges, offering shorter courses and requiring less public funding. Teaching methods should change, placing less importance on rote-learning, erudition and applied problems, and greater emphasis on active learning and preparation for responsibility-taking.

the necessity of undertaking or partipating in the reconstruction of technical education in agriculture (teacher training, redefinition of course contents and teaching methods...) for which there is a high social demand owing notably to the emergence of a new class of small farmers. The development of this type of intermediate qualification is not generally looked on with much favour by univenities, which prefer the prestige element attached to higher level studies. Yet this type of strategy should encourage the restructuring of the universities by offering interesting prospects for those members of the academic staff whose technical knowledge is no longer indispensable in university courses; 6 the emergence of competition from other types of education delivered in different institutions, which threatens the traditional monopoly of agricultural universities in the rural and agricultural world. We may mention in particular courses in economics, pure and applied biological sciences and food technology.

The situation is all the more serious that development prospects in the agricultural and food sectors are still not easy to define. The lack of an agricultural policy in the majority of these countries, the difficulty of forecasting how these economies will dovetail into the western agricultural nations leave many professionals and leaders perplexed. They also serve as a useful excuse for inertia and lack of vision.

ln our view, it is indeed possible to identify guidelines for the future, at least to the extent of defining the direction which thinking on future higher education in the agricultural sciences should take in these countries.

ry -NEW PRIORITIES FOR TEACHTNG IN THE AGRICULTURAL SCIENCES :

Within the general context described above, three major preoccupations should, in our view, guide the actions of those in charge of reorganising teaching in the agricultural and food sciences.

I ' Redeftnition of the role and function of managers in the food-chain :. The situation in the food-chain has been the subject of study by experts in the last few years. Their conclusions underline shortcomings in agricultural production and transformation (farm structures and industrial equipment and labour...) which appear outworn and obsolete, with a poor level of technical and economic performance, producing goods whose quality does not conform to current Western European norms. They also point out the poor structuring of the food-chain, resulting from lack of organisation among producers, difficulties in storage and packaging, disorganised and inefficient distribution, changing types of consumption, the ever-present role of the state... With the setting-up of new structures of agricultural production and transformation, the need for highly specialised technicians familiar with the technical management of large production units will begin to fall (BARLOY et a1.,1992;RUFFIO er al., 1993). Little by liffle there will emerge a demand for executives capable of taking responsibility for the technical and economic management of agriculture ("agricultural development"). In the same way, the application of market economy rules will oblige all those concerned in the food-chain to be actors in the market. Their organisation will require managers capable of coordinating activities at different stages in the chain (agriculture/industry relations, extension services, structuring of farmer's production groups...), the organisation and logistics necessary for the marketing of products and the creation of essential services (financing of activities, insurance of goods and persons, risk insurance, health and unemployment cover...)

The reorganisation of new production units, both agricultural and industrial, will require specialists able to participate in the planning of those reforms which they will be responsible for putting into practice. They will have to define their legal, economic, social and technical aspects.

Since the nature of their work will be changing, university graduates in agricultural sciences will have to possess new skills. The political criteria of "loyalty and docility", âDd economic criteria of "high-level technical specialisation" which used to determine recruitment will have to give way to new demands :

the possession of news areas of competence : economics, management, law, social sclences...

greater professional mobility, in a context where the horizon is not limited to public service and a single unit of production.

polyvalence, flexibility, autonomy in action and decision.

Three principles should therefore guide decisions concerning students' education. They are far more important than the frequent debates focussed on subjects and teaching hours, rather than on the content of teaching and on its ultimate objectives.

These principles are :

a strong basic scientific training, sufficiently broadly based to give future graduates the capacity for abstract thought, rigorous reasoning and a greater facility in building theoretical concepts, preparing their formulation and expressing technical problems in scientific terms, a more limited technical training, crucial indeed but not aiming at encyclopaedic knowledge. It should be based on models illustrating the fields of application of knowledge, giving working methods, developing a sense of reality, an open mind and an a\ryareness of the complex nature of biological, technical and economic problems.

the development of personal qualities essential in positions of responsibility : communications and management skills, ability to organise and adapt, to work hard and rapidly... The student's personality may be developed along these lines by various types of exercices : individual or group projects, written and spoken communication, language learning and training periods... 2 -Replacement of a production orientated approach by an overall approach to the problem of rural development.

Beside the questions raised above concerning the primary production domain, the whole of the rural world is also suffering from a geographic and social structure inherited from the period when agriculture was becoming industrialised. The results are a lack of land management, a low development of rural areas, unsuitable or non-existent public services and equipment, hidden unemployment and damage to the environment... Quite apart from the strong public pressure on the question, there exist considerable employment opportunities and needs for specific skills in the areas of rural planning, the protection and development of the countryside... Universities of agricultural sciences must take up this challenge if they are to continue to justify the resources currently at their disposal, given the impossibility of predicting strong growth in employment opportunities in the food-chain at the present time. The situation is all the more worrying that the annual output of graduates in this domain is traditionally high, and many of them are already seeking employment and in need of retraining and career advice and assistance.

Moreover, this field of investigation does not come within the area of competence of most universities of agricultural sciences, and there is a considerable risk of seeing competition appear in this area from rival institutions : faculty of biological sciences, of economics and social sciences... Finally, the appearance of new social preoccupations, for example the protection of the environment, oblige the agricultural scientist to think on a wider scale, beyond the level of individual plots, to consider the farming system beyond the individual production unit and concern himself with how they fit into a larger agrarian system, a catchment basin or a particular chain of production, for instance.

ln other words, we should no longer approach agriculture and the food-chain in terms of production and productivity : instead we should encourage notions of quality, coordination and an outward-looking approach.

On a yet wider level, this means that the universities can and must become privileged partners in local and regional developmenÇ in partnership with local authorities ànd professionals from the business world, within structures yet to be created. They will be able to mobilise their specialised knowledge and profit from the experience in training opportunities for their students. Material questions and the search for financial resources to compiernent state funding should form part of this action.

3 -Recognition of the educational value of biologîcal scïences as both models and tools în the acquisition of knowledge and the matugement of complex systems.

Questions concerning the future of agricultural higher education in Central and Eastern Europe are also a manifestation of the identity crisis affecting this sector of education in Western Europe. lndeed, the lessening political and economic importance of the food-chain in industrialised countries, together with the recession in the sector and the calling into question of its way of producing (notably in the context of the Common Agricultural policy ieform) lead to questions on the very continuation of this type of education. Falling recruitment anà fewer job opportunities in several Western European countries are the outrvird manifestation of this, sometimes masked by particular local institutional cases (some establishments being very firmly entrenched indeed), or by the persistence of a particular social standing oi recognition attributed to the holders of a particular qualification (often linked to a title or membershipof aprofessionalbody).

.::i On a deeper level, we are no doubt confronted with an epistemological crisis in the discipline, which can be summed up in the question "do the agricultural sciences exist ?" or "how can one justify the existence of teaching and institutions specialised in agricultural sciences ?". Progress in pure and applied sciences has been so rapid that frontiers between disciplines are disappearing, as demonstrated by the appearance of the bio-sciences (bio- chemistry, bio-technology, bio-mathematics, bio-economics...). Universities teaching agricultural sciences have long been justifying their existence by public demand (specialist advice to agriculture) and the practice ofobjective-orientated teaching and research, according priority to the object rather than the methods of study. This situation has been called into question by an overall orientation towards the pure sciences over the last twenty years, particularly in Northem Europe, and indeed at times by questions concerning the nature of the qualification itself. The replacement (or suggested replacement) of the traditional agricultural sciences degree by biology or bio-engineering diplomas is indicative of cunent thinking in some universities (in Belgium, France and the Netherlands, for example).

These questions are central to a debate in Western Europe which will also affect the countries of Central Europe. [n our view, the most fruitful prospect involves taking our universities and our training out of the agricultural "ghetto". This strategy implies improving the recognised value of this education in the eyes of society and of employers. The agriculture and food sector must be acknowledged as a pertinent basis and model for intellectual training in the application of specific analytic approaches. [n our society, the management of complex problems is at the heart of all contemporary problems, whose terms of reference are notions of balance, regulation and feedback, whether one is managing a company, govemment economic or social policies, ecosystems, or individual or public health... Who better than the agricultural scientist knows how to approach complex biological systems and apply integrated and interdisciplinary approaches? Managers qualified in agricultural sciences are better placed than others to act outside their specific domain in positions which demand the skills and the aptitude to manage complex problems. ln these conditions, the future of agricultural higher education requires a determined effort of explanation and demonstration towards the society and an ambitious adaptation of the type of education offered. Widening of the social origins of students, a wider range of career opportunities and priory given to general basic intellectual and scientific training are necessary conditions for success.

It is certain that social demand in Eastern Europe is still likely to be formulated, for some time, in terms of skills in the agricultural and food sector, if only because of the desperate need to restructure this sector. Howerer, given the considerable existing infrastructure of higher education, whose financing will increasingly have to be justified in a context of shrinking state budgets, it seems essential for agricultural higher education to broaden its area of activity as of now.

V. CONCLUSION: Restructuring agricultural higher education in Central and Eastern Europe poses a threefold problem. It is involved in overall reorganisation of higher education in these countries but also in certain specific aspects of the economic, technical and social situation of the sector, as well as in defining the position this type of education will occupy within higher education as a whole.

These questions affect both institutions (their continued existence, their organisation and running), study programmes (in terms of objectives, structuring, content and teaching methods) and actors, be they teachers or students (motivation, ability to accept change, expectations...). Some of these questions are also at the heart of current or recent reforms in several Western European countries (Spain, Italy and Portugal for example).

LL

'-.j,i.'...i;'j I


Growth hormone and thyroid hormone levels during smolting in different populations of atlantic salmon

Gilles Boeuf, Pierre-Yves Le Bail

To cite this version:

Gilles Boeuf, Pierre-Yves Le Bail. Growth hormone and thyroid hormone levels during smolting in different populations of atlantic salmon. Progress in Comparative Endocrinology : Proceedings of the Eleventh International Symposium on Comparative Endocrinology held in Malaga, Spain May 14-20, 1989, 342, Wiley-Liss, 752 p., 1990, Progress in Clinical andBiological Research, 0-471-56800-7. hal-02850434


est destinée au dépôt

In our laboratory, fragments of zygotic embryo are presently the best plant material to induce somatic embryogenesis in walnut. This induction can happen only in a very short time-window of the fruit developement. To gain control over the embryogenic induction process we have investigated the hormonal state of the zygotic embryo during the development of the nut including the period when somatic embryogenesis induction is possible. Development of the nut has been characterized by measurements of its volume and weight. Volume of liquid endosperm per nut and mass of the embryo have been determined. Indole-3-acetic acid (IAA), abscisic acid (ABA), zeatin riboside (ZR), zeatin, isopentenyladenine (IP) and isopentenyladenosine (IPA) were measured by enzyme-linked immunosorbent assay (ELISA) in the embryo and the associated liquid endosperm at ten different dates from 15 days after pollination (DAP) to 91 DAP during the nut development. Embryogenic induction rates were also measured and were optimal between 56 and 63 DAP. Results show undetectable levels of IP, IPA and Z in these tissues all along the period tested. ZR was detected in the endosperm (up to 0.15 nmol/embryo), and in the embryo (up to 0.35 nmol/embryo). ABA and IAA were low in the endosperm (0.1 and 1 nmol/embryo respectively) compared to the embryo content (up to 1.2 and up to 33 nmol/embryo respectively). These results are discussed with respective embryogenic induction rates of the corresponding zygotic embryo tissues. Exogenous hormonal requirements for embryogenic induction are discussed in relation with endogenous hormonal state of the zygotic fragment treated in the embryogenic induction process. This is the first report of a possible relationship between endogenous hormonal status of a tissue and its further ability to somatic embryogenesis induction.

Indol- 3

 3 -acetic acid, abscisic acid and cytokinins endogenous levels in endosperm and embryo of walnut (Juglans regia L.) during nut development Philippe Label, Isabelle Lucas, Claude Joseph, Daniel CornuTo cite this version:Philippe Label, Isabelle Lucas, Claude Joseph, Daniel Cornu. Indol-3-acetic acid, abscisic acid and cytokinins endogenous levels in endosperm and embryo of walnut (Juglans regia L.) during nut development. 8.

  Institut National de la Recherche Agronomique, Station d'Amélioration des Arbres Forestiers, Avenue de la Pomme de Pin, F-45160, Ardon, FRANCE ; 2. Université d'Orléans, Faculté des Sciences, Laboratoire de Biologie des Ligneux Forestiers, F-45067, Orléans Cedex 02, FRANCE.

		http://www.inra.fr/prodinra
		INDOLE-3-ACETIC ACID, ABSCISIC ACID AND CYTOKININS ENDOGENOUS LEVELS IN
		ENDOSPERM AND EMBRYO OF WALNUT (JUGLANS REGIA L.) DURING NUT
	Manuscrit d'auteur / Author manuscript	DEVELOPMENT. P. LABEL 1 , I. LUCAS 1 , C. JOSEPH 2 & D. CORNU 1 1.
	Manuscrit d'auteur / Author manuscript	108. hal-02850459	p.
	Manuscrit d'auteur / Author manuscript

International Congress of Plant Tissue and Cell Culture, Jun 1994, Florence, Italy.


Francois Bonnieux

D Vermersch

Valuing sea-trout angling : a contingent experiment in western France

niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

The main findings of the on site survey are summarized in the first paragraph whereas the rest of the paper is devoted to the contingent component of the research.

ONSITE SURVEY RESULTS

Information on the survey was given in local newspapers and T.V. As a matter of fact the fishermen welcomed the interviewers. The questionnaire is quite long and it was expected the face-to-face interview would need no more than 20 minutes. But most individuals wanted to add comments which are often valuable, . 50 it usually took 30 minutes. It reviews anglers' characteristics, fishing experience and effort, and expenditures. Let us notice that the only question for which non-response is significant involves income. People were asked to locate their family income on a ladder and 25% refused. But for thõ ther 75% answers are consistent with age and occupation.

The main results of the onsite survey are reported in table 1. Sea-trout angling is a male recreation (only one lady was met) and people surveyed are wealthy compared with the French population. The value of equipment and the length of a fishing day are high. On the average anglers fish in the Touques 24 times per season 50 the number of hours per fishing season equals 120. But there are significant differences between residents and tourists. Residents travel relatively short distances and visit the river more often than tourists who spend more time on the river, fishing for a week-end or a week. That is, the tourists substitute length of trips for the number of trips in a fishing season. This behaviour is weil known in recreational economics [START_REF] Bell | Recreational demand by tourists for salwater beach days[END_REF].

Average round-trip distance is close to figures obtained for salmon angling in France [START_REF] Bonnieux | French experiments in contingent valuation: two case studies[END_REF] and reported elsewhere, for example to participate in angling activities in Maryland (Walsh, 1986, p. 14). Consumer sumlus ner davm 160

(1) Approximation.

(2) Includîng reels, rads and lines.

(3) Includîng licence, fishing society fees, special fees for salmon and sea-trout (4) Includîng transportation costs, food, lodging, fishing and depreciation of equipmenl. F: French Franc IF = .18 US $ Anglers are not very successful in terms of fish caught : 3.5 per year, but 48 % did not catch any trout ! ln any case they enjoy their experience since 90 % plan to come back next year and only 30 % fish in a river substitute. 50 it is quite clear that the quality of fishing experience have many attributes.

ln most cases the trip is intended for angling only since multiple objective visits only concern 4 % of people surveyed. Sea-trout angling is expensive in terms of equipment. fees and transportation costs but cheaper than salmon angling [START_REF] Bonnieux | French experiments in contingent valuation: two case studies[END_REF]. The average cost of a fishing season equals 5 769 F but there is a significant difference between residents and tourists : 4 855 F and 9 450 F respectively. These figures are consistent with values concerning comparable situations. Radfort et al. (1991) have considered salmon and sea-trout angling in England and Wales. They got 4 270 F per season but regional averages range from 2 960 F to 10460 F.

Consumer surplus per fishing day has been obtained using the travel cost method. Price per trip to the Touques river includes car operating costs plus food and lodging expenditures. Distanée traveled has been also considered to take into account the oppotunity cost of traveling time. Moreover the fishing demand equation incorporates angler's income, value of equipment and the existence of a river substitute. the average surplus reported in table 1 is very closed to surp/uses given elsewhere. For examp/e in Norway, [START_REF] Navrud | The use of benefits estimates in environmental decision making in Norway[END_REF] has obtained values ranging from 100 F to 250 F for trout and salmon.

OUTLINE OF THE CONTINGENT VALUATION EXPERIMENT

The main issue concerns new opportunities to improve fishing experience. Until the 1990 season, only 26 km of the Touques banks, upstream from the mouth, were devoted to recreational fishing. The building of a fish ladder could give new opportunities to increase the length of banks available for angling since trouts will proceed further 45 km up the river. But these banks are privately owned so angling societies wish to obtain an access to the river in order to increase recreational angling supply and therefore improve the fishing for their members.

One possibility would be to buy a narrow corridor along the river provided enough money is collected. Thus the CV study emphasizes this point since people were asked to voluntarily participate in a fund to buy 5 km of river banks. A questionnaire has been successfully tested on site during the last stage of the onsiste survey in October 1990 and 50 individuals were asked and answered questions. Then we sent a questionnaire to each angler surveyed before October who had given his address, 97 questionnaires were mailed and 47 returned (response rate 48%).

Pooling together both subsamples provides a sample of size 97. A majority of 75 anglers wish to benefit of greater facilities in order to be able to fish upstream from the fish ladder and 51 agree to participate in a fund to buy 5 km, knowing they would be entitled to fish freely for three years. The payment card elicitation method has been used in order to assess the willingness to pay for 5 km. Ali anglers give an amount greater than zero, the average amount equals 578 F. There is an Iteration in order to assess the average amount to buy 5 km more. 40 were willing to pay and the average amount equals 567 F.

Unfortunately the sample size was too small to run a new stage but it is interesting to notice that the number of positive answers decreases.

A secondary issue has been also considered. There are some problems with poachers who use nets to catch fish in the river mouth. 50 surveyed ang/ers were asked about their willingness to pay to hire more river-keepers. It is interesting to notice that protest answers are significant, 40% of the sample refuse to pay because they already pay taxes for police control so a private body (the fishing society) should not take the role of the state. However 50%

give positive amounts ranging from 20 F to 500 F per year. The average amount equals 160 F.

Let us focus on the first scenario for which there is no protest answver.

People are very familiar with the point because there is still agame angling market. They still pay something : a Iicense to combine angling societies and specifie fees to get access to river banks. 50 it could be argued that hypothetical bias is not a severe problem in this experiment. The deal we proposed them is a simple extension of the actual market. It involves an increase in the supply of a rationed good : river banks available for angling.

Basically anglers were faced with a dichotomie choice as they were asked to accept or reject voluntarily participation in a fund. 50 in the first step of the experiment the dependent variable is a yes/no answer. A probit and a logit model have been estimated and results are reported in table 2 with 6 independent variables. Two variables, income and years of training, help to describe anglers. Value of equipment is a proxy for fishing effort, and catches (number of sea-trout caught during thr 1989 season) are an indicator of fishing experience in the Touques river. We have defined a dummy variable to take into account substitute rivers and we have also considered the distance traveled to angling place as a potential factor influencing demand. Both models provide similar results. They are statistically poor but the signs of the coefficients look correct. There is good reason to believe that the demand for game angling rises with income so the positive coefficient for this variable was expected. Moreover anglers who own many reels and rods (the average is 2.6 for each type of equipment but 20% own more than 5) make a greatest fishing effort. Therefore the value of equipment. which is a proxy for fishing effort. positively affects demand.

The positive signs for the dummy variable for substitute sites and for the distance are consistent. First, anglers who fish in substitute rivers are expected to have greater requirements in terms of fishing experience. Second. anglers living far from the Touques will stay for a week-end or for a vacation in the Touques area. For both categories the length of banks available for angling is limited so they are Iikely to ask for extra km, so the underlying explanatory variables positively affect angling demand.

The negative sign of the years of training variable requires some explanation. First let us notice this variable is positively correlated with the angler's age. However sport fishing demands great physical effort. Some of the comments support this point and indicate that senior citizens sometime move to other types of fishing. The current availability of banks fullfills their requirements. Finally we have a negative sign for the catch variable, this result is obviously inconsistent with our expectations.

WTP FOR SEA-TROUT ANGLING

Probit anf logit models do not use ail the information available, so to go further let us first consider anglers who are willing to pay a positive amount to increase angling supply. A positive WTP implicitely means a greater demand.

For those who reject the deal there is empirical evidence that some of them are unsatisfied with their fishing experience and that others only fish a small portion of the river. The comments they made show they would like to reduce the fishing fees. Thus for this category a negative WTP would be logical but they do not have the opportunity to give it.

The length of river banks available for angling cannot be chosen by the individual angler. The problem with measuring household welfare when there are quantity constraints arises from the absence of an observable set of priees with which to value changes in the consumption bundle. To deal with this issue let us consider the dual minimization problem, where the angler must minimize the expenditure required to obtain a given level Uo of utility at given priees. That

is, Min p'x. x x u(x,z,m) ~Ua Z E Z,cR+ [1 ]
where x is the vector of private goods and Px the vector of priees of private goods. Zf is a subset of the commodity space which includes rationed goods. There is only one quantity constraint so Zf dimension is one and z equals the length of river banks available for angling. The vector m represents angler's characteristics such as age, fishing expensive, catches, income ...

Providing that the utility function is well-behaved we can define the constrained expenditure function e (Px' zo, m, uo) where the subscript 0 denotes the initial situation, so Zo equals 26 km. then total expenditure equals, [2] where 2 0 equals the amount of specifie fees to fish in the Touques.

enjoying 26 km of river banks.

To enjoy an increase in the quantity constrained good z such as z1 > Zo the individual angler is willing to pay 21. That is :

[3) then [4)
So the angler's answer is the difterence between two expenditure functions, but it is important to notice that he is not necessarily in long run equilibrium. This is the rationale to consider the potential occurence of negative WTP.

Following Carson (1991, p. 123) equation [4) is expressed in ah equivalent form known as the income compensation function. It is given by

WTP (~z) = f (Px' z, m, e o )
where ~z = z1 -zoo [5) Then the sample of people surveyed has to be broken down into two categories. The first subsample refers to anglers who are willing to increase the fishing fees they still pay. Face to an hypothetical increase in the length of river banks available for angling they reveal a demand increase for the rationed good (M > 0) because the quantity constraint is binding. So they are willing to pay 21 instead of 2 0 knowing that total expenditure is constant, see [3) then,

WTP = WTP ( ~z) if 21 > 2 0 [6)
ln the second subsample a nul WTP is observed. In order to enjoy an increase of river bank supply, anglers would have to give up private goods.

Moreover the quantity constraint is not necessarily binding and some of them are willing to decrease the fishing fees they have to pay but they do not have the opportunity to give a negative WTP. For the laner an increase of z implying an increase in the specifie fishing fees would result in :

RESULTS AND COMMENTS

The model was estimated by the maximum Iikelihood with a Newton-Raphson algorithm. Standard errors of coefficients were computed from the inverse of the observed information matrix. Results are reported in table 7, x*i being expressed in logarithm. We think that hypothetical bias is not a serious problem in this study because there is already a market for game angling. People are not confronted with an imaginary situation therefore we can expect they behave the same way in actual market. The most difficult point concerns non-responses which in this survey correspond to a strategie behaviour. To deal with that, we intend to improve the model specification, using a generalized tobit mode/.

  equation [3) would be violated. Therefore :To deal with both categories let us write, specify a tobit model with a specifie threshold for each observation. The model uses the first category of anglers to derive what would be the optimal WTP, so the underlying logic takes into account negative WTP which are not observed but which do exist.

Table 1 .

 1 Sea-trout angling basic data

	Sea-trout

Table 2 .

 2 Sea-trout angling demand: probit and logit models.

	Variables	Probit	Lol!it
	Intercept	0.657 n:n	1.00 (1.4)
	Dummy:	0.318	0.581
	site substitute	(0.6)	(0.6)
	Trip distance (km)	0.008	0.014
		(1.7)	(1.6)
	Value of equipment (F)	0.017	0.024
		(0.7)	(0.5\
	Catches	-0.002	-0.0049
		(-0.3)	(-0.3)
	Monthly income:	0.0001	0.0002
	17 classes (increasing	(0,3)	(0,2)
	with income)
	Years oftraining	-0.023	-0.034
		(-1.0)	(-0.8)
	Lo2 Iikelihood	-24.95	-25.15
	asymptotic t values in parentheses

)

Table 3 .

 3 Sea-trout angling demand : tobit modelThe results reported in table 2 and in table 3 can be compared since they are based on the same sample and the same independent variables. The tobit model seems better because ail signs are consistent and t-ratios are greater. As expected a positive correlation of catches on angling demand is obtained. A comparison between model 1 and model 2 help to clarify the understanding of the angler's behaviour. In a first stage he decides to travel to the river and in a second stage he determines the duration of his visit, so there a negative sign for the visit type variable and also for food and lodging expenditures. Angler's age is a proxy for income and positively influences WTP in models 2 and 3. Models were used to estimate average WTP for the first 5 km section and the second one. We got amounts per angler which are smaller than the values given above and based upon a samp-Ie mean. It is consistent as the tobit model implicitly takes into account negative WTP.

	First 5 km section	Second 5 km

Table 4 .

 4 Aggregate WTP per km and per year (F) If we assume the surveyed individuals to be representative of individuals angling in the Touques river, it is possible to assess aggregate amount for extra km. Values reported in table4are not very robust because sample size is quite small they make sense since they are consistent with the yearly rent (including restoration, cleaning up and maintenance).

			First 5 km section		Second 5 km section
	Rent	Sample mean 1	Model!	1	Mode! 2	Sample mean 1	Mode13
	15000 à 20 000	26300	1	16500	1	12620	20200	1	12650