B Soula

F R Goebel

P Caplong

H Karimjee

R Tibere

E Tabone

TRICHOGRAMMA CHILONIS (HYMENOPTERA : TRICHOGRAMMATIDAE) AS A BIOLOGICAL CONTROL AGENT OF CHILO SACCHARIPHAGUS (LEPIDOPTERA : CRAMBIDAE) IN REUNION ISLAND : INITIAL FIELD TRIALS

Keywords: sugarcane, biological control, Chilo sacchariphagus, Trichogramma chilonis, parasitoids, stalk borer, Reunion Island

Introduction

Chilo sacchariphagus Bojer (Lepidoptera: Crambidae), is a key pest in southern Asia and the Indian Ocean islands, and recently in Mozambique. In Reunion and Mauritius, this borer has been a serious pest since it was introduced with sugarcane during the 19th century [START_REF] Williams | The sugar cane stem borer (Chilo sacchariphagus) in Mauritius[END_REF]. In Reunion Island, C. sacchariphagus can cause important yield losses, particularly in the susceptible variety R579, where 10-30 tons cane/ha can be lost [START_REF] Goebel | Caractéristiques biotiques du foreur de la canne à sucre Chilo sacchariphagus (Bojer, 1856) (Lepidoptera : Pyralidae) à l'île de la Réunion. Facteurs de régulation de ses populations et conséquences pour la lutte contre ce ravageur[END_REF].

During the 1960s in Reunion and Mauritius, several attempts were made to control C. sacchariphagus using exotic parasitoids, with variable results. Various parasitoid species were introduced and mass releases made, and some, for example Trichogramma chilonis Ishii (Hym: Trichogrammatidae) and Cotesia flavipes Cameron (Hym: Braconidae), were successfully established in sugarcane fields [START_REF] Etienne | Tentative d'implantation de deux espèce de tachinaires contre Chilo sacchariphagus à la Réunion[END_REF][START_REF] Williams | The sugar cane stem borer (Chilo sacchariphagus) in Mauritius[END_REF]. However, the natural densities of these parasitoids were not sufficient to control C. sacchariphagus.

In order to improve and optimise the use of such natural enemies in biological control programmes, a better knowledge of the bio-ecology of C. sacchariphagus and its natural enemies is needed.

On Reunion Island, a new biological programme using Trichogramma chilonis began in 2000, through a partnership between the Centre de coopération internationale en recherche agronomique pour le developpement (CIRAD), the Institut national de recherches agronomiques (INRA) and the Fédération départementale des groupements de défense contre les ennemis des cultures (FDGDEC). This parasitoid was chosen because (i) it is the most naturally frequent parasitoid of C. sacchariphagus in Reunion island, (ii) it is an egg parasitoid and kills the pest before it can damage cane, (iii) the past 20 years have seen considerable use of this biological control agent on a very large scale on corn, sugarcane, cotton, fruit trees and vegetables in more than 30 countries [START_REF] Li | Worldwide use of Trichogramma for biological control on different crops: a survey[END_REF], and (iv) in sugarcane, Trichogramma sp. are considered to be effective egg parasitoids of many lepidopteran stalk borers [START_REF] Metcalfe | Egg parasites (Trichogramma spp.) for control of sugar cane moth borers[END_REF][START_REF] Nagarkatti | Biosystematics of Trichogramma and Trichogrammatoidea species[END_REF][START_REF] Browning | Indigenous and exotic Trichogrammatids (Hymenoptera: Trichogrammatidae) evaluated for biological control of Eoreuma loftini and Diatraea saccharalis (Lepidoptera : Pyralidae) borers on sugarcane[END_REF][START_REF] Pham | Results of utilization of Trichogramma chilonis for biological control of sugarcane stem borers[END_REF].

Inventory and selection of egg parasitoids were completed in 2000 [START_REF] Goebel | Biological control of the sugarcane stem borer Chilo sacchariphagus (Lep: pyralidae) in Réunion Island: current and future studies on the use of Trichogramma sp[END_REF]. The adults were collected in the field with egg-traps of C. sacchariphagus or Galleria mellonella Linnaeus (Lep : Pyralidae), a factitious host of Trichogramma in the laboratory. Each Trichogramma strain found in selected areas was reared separately in the laboratory and samples of adults were identified, using morphological (male genitalia) or molecular (RAPD) techniques. Only T. chilonis was identified [START_REF] Goebel | Biological control of the sugarcane stem borer Chilo sacchariphagus (Lep: pyralidae) in Réunion Island: current and future studies on the use of Trichogramma sp[END_REF].

In 2001, bionomics of three geographically distinct strains of T. chilonis were compared on the basis of their functional response to host density, the time of development and several demographic parameters of the adults (Reay-Jones, 2001). The strain from St-Benoit (a hot and rainy region in the north-east of Reunion) presented the best performances and was chosen for mass production and augmentative release programmes. This production was done on G. mellonella, which is easier to rear than C. sacchariphagus.

This paper summarises the first season of results from inundative releases of T. chilonis against C. sacchariphagus. Future research ideas and developmental perspectives are also presented.

Methods and Materials

In 2002, field experiments were conducted at two sites: Savannah (SAV) and Sainte-Marie (SMA) with dry and wet climates, respectively (Figure 1). Both sites are planted with the susceptible variety R579, and experiments during previous years showed high borer infestation [START_REF] Goebel | Caractéristiques biotiques du foreur de la canne à sucre Chilo sacchariphagus (Bojer, 1856) (Lepidoptera : Pyralidae) à l'île de la Réunion. Facteurs de régulation de ses populations et conséquences pour la lutte contre ce ravageur[END_REF]. [START_REF] Goebel | Caractéristiques biotiques du foreur de la canne à sucre Chilo sacchariphagus (Bojer, 1856) (Lepidoptera : Pyralidae) à l'île de la Réunion. Facteurs de régulation de ses populations et conséquences pour la lutte contre ce ravageur[END_REF] and [START_REF] Goebel | Prédation par Pheidole megacephala (Fabricius) (Hym.: Formicidae) des oeufs de Chilo sacchariphagus (Bojer) (Lep.: Pyralidae), foreur de la canne à l'ile de la Réunion[END_REF][START_REF] Goebel | Biological control of the sugarcane stem borer Chilo sacchariphagus (Lep: pyralidae) in Réunion Island: current and future studies on the use of Trichogramma sp[END_REF] showed that predation of borer eggs mostly by the ant Pheidole megacephala Fabricius (Hym : Formicidae) was high (80-90%) during late growth stages of sugarcane, especially after six months old. Inundative releases were therefore planned for the early growth stage (about two months old), when predation is low and sugarcane is most susceptible to the borer. Unfortunately, the tropical cyclone Dyna occurred in January and delayed the trials, which began in February on cane aged three and four months at SAV and SMA, respectively. At each site, eight plots of 500 m 2 were set up, and half of them were treated with releases of 150 000 T. chilonis per hectare, each week over a period of four months. Treated plots were set up at least 20 m apart from the control ones (minimum 20 m) to avoid any migration of adults after releases.

In both treated and control plots (untreated check), infestation of C. sacchariphagus and parasitism levels were studied through damage to stalks and internodes. Each month during releases (from February to May) a sample of 400 stalks (100 per plot chosen randomly) was dissected carefully to assess the borer damage. At harvest, crop loss was estimated by weighing the same number of stalks.

Results

At SMA, the percentage stalks damaged increased from 10% at the time of first release to 88% (treated plots) and 100% (control) at harvest, but these results were not significantly different.

Results were similar at SAV, although overall infestation was lower (53% and 66% in treated and control plots respectively). At harvest, the percentage of bored internodes, which is an accurate measure of damage, decreased dramatically in treated plots at both sites (Figure 2) which could be due to a lower number of larvae. Similarly, the mean stalk weights were 17% (SMA) and 14% (SAV) higher in treated plots (Figure 3). Yield estimations in cane production have shown a gain of 17 tons/ha at SMA (from 102 to 119 t/ha) and 15 tons/ha at SAV (from 107 to 122 t/ha).

  a biological control agent of Chilo sacchariphagus (Lepidoptera, Crambidae) in Reunion Island : initial field trials -Soula B., -Goebel F.R., -Caplong P., -Karimjee H., -Tibere R., Elisabeth Tabone To cite this version: -Soula B., -Goebel F.R., -Caplong P., -Karimjee H., -Tibere R., et al.. Trichogramma chilonis (Hymenoptera : trichogrammatidae) as a biological control agent of Chilo sacchariphagus (Lepidoptera, Crambidae) in Reunion Island : initial field trials. 77. South African Sugar Technologist' s Association Congress, Aug 2003, Durban, South Africa. 77, 2003. hal-02831092

Figure 1 .

 1 Figure 1. Location of the two sites in Reunion Island used for field releases of Trichogramma chilonis in biological control experiments against Chilo sacchariphagus.

Figure 3 .

 3 Figure 2. Percentage internodes bored in check and treated plots at Sainte-Marie (a) and Savannah (b) during 2002. Black stars indicate significant differences (P<0.05).

Acknowledgements

The authors wish to thank Emmanuel Fernandez (CIRAD) and Karine Clain (FDGDEC) for their contributions to the current programme. We are also grateful to the scientists and the technicians at INRA for their involvement, especially Nathalie Lescano and Bernard Pintureau. This project is funded by the Conseil Général de la Réunion and Europe-FEOGA (Fond Européen d'Orientation et de Garantie Agricole).

Discussion and Future Prospects

The results of these first experiment trials allow efficient biological control of stalk borer populations in Reunion Island to be envisaged. Although inundative releases were delayed by cyclone Dyna, encouraging results were obtained. In late 2002, new releases were initiated, taking account of the previous experiments. The first releases were made earlier (one month old cane) than in 2002, to coincide with the infestation of sugarcane leaves by young larvae in the initial trials. Moreover, the number of T. chilonis released was modulated (100 000 or 200 000 per ha), according to variations in borer density. The effectiveness of these new releases will be estimated at harvest in late 2003. To date, results based on internodes bored and Trichogramma efficiency (presence in egg traps) show that the treated plots are about 50% less infested than the check plots.

In 2003, studies on bionomics will continue in the laboratory using two hosts (C. sacchariphagus and G. mellonella), especially on the strain originating from the region of Sainte-Marie, which is highly infested by the stalk borer. Further studies on pest-parasitoid population dynamics are also needed to optimise the field releases with parameters such as time, frequency and duration of releases, and number and distribution of release points. Knowledge of the influence of climatic and agronomic factors on population dynamics is also essential, and is being studied with the aim of modelling these interactions. Finally, the likely success of this biological control programme could lead to the generalisation of T. chilonis releases in most coastal sugarcane areas. Different parameters concerning quality of production and logistics (holding/storage/transport) should then be investigated. These parameters will be increasingly important as T. chilonis releases become commercially viable.


Julien Salanié

Philippe Le Goffe

rcy AND pRopERTy RTGHTs IN FRANCE: AN ECOI{OMIC APPROACH

Ronald Coase has shown that well-defined property rights and the absence of transaction costs ensure that bargaining can lead to efficient environment allocation. In France, as in most developed countries, fishing rights are well-defined and belong to land-owners. However in many cases these rights are traditionally given for free to anglers associations (AAPPMA). AAPPMA are the basic institutions in charge of angling management in France. In a first part we describe how private fishing rights are institutionally turned into public goods. This is the basis of the French democratic angling rule : fishing "everywhere, for everyons and at low cost".

In a second part we analyze the economic drawbacks of foregone property rights. Two main external effects arise from the public nature of recreational fishing in France. First we deal with externalities between anglers, known as the "tragedy of the comrnons". Then we describe the extemal effects between land owners (mostly farmers) and anglers. This leads to pollution and loss of environmental services, At present in France, the management system in place relies only on public policy to solve the externality problem because property rights are given up. Public intervention is necessary in many cases. In the last part we explore the compatibility between the Flench egalitarian angling system and better economic efficiency and anglers' welfare. For specific extemalities we suggest the possibility of fishing rights bargaining between AAPPMA and land-owners. Efficient pricing by AAPPMA could simultaneously cope with congestion, if any, and environmental management.

In conclusion we suggest how economic research could contribute to quantify these externalities and clarify the policy debate by quantifying the demand for angling.

Introduction

this fishing right as a property right, but it is indeed a right to use the resource. Property rights include the right to fish and the duty to maintain the environmental quality at the site where the right does apply. The This paper looks at the efficiency ofrecreational flshing management in France. We argue that angling policy is not leading to efficient resource allocation.

Because we believe that this inefficiency can be ex- plained by the structure of property rights, the paper is organized as follows. Firstly we present fishing right management in France. Secondly, we explain how economic theory provides analytic tools for the interpretation of external effects by focusing on properfy rights. Finally, we show that property-right enforce- ment could regulate some ofthe negative externalities affecting angler's welfare.

How angling policy has led to the loss of fishing rights in tr'rance:

historical and institutional reasons

In France, fishing rights belong to landowners, as rn many countries. We will refer in the following text to

In the Middle-Ages, fishing rights belonged to the Lord. Fishing rights were viewed as privileges and were abolished by the French revolution of 1789. At this stage, anyone could go fishing anywhere @reton, 1993). Soon after, in 1794, fishing rights were re-es- tablished. In the early 20th century sport flshermen achieved the recognition of angling in comparisson to commercial fi shing (Thib ault, 1992). Recreational fishing was free, until a law was introduced on July the lZth,1941. This law abolished free recreational fishing by obliging every angler to paying a fee to an anglers association (AAPPMAt). This situation is still true today. Even a property right owner has to acquire a fishing license to fish, even where he owns the right.

luilutiluilillfilt{llil [ltl{lt lilt

JurtEru SlurulÉ auo Putuppe Lt Gorrz In France, the agencies in charge ofrecreational fishing management are theAAPPMAs. They are aggre- gated into departmental and regional federations.

AAPPMAs are concemed with the management of recreational fishing as well as the environmental quality of waterways. The application of the law concern- ing angling is assumed by the government agency responsible for inland fishing (CSP'z).

Adequate property rights must be specified com- pletely, transferable and enforced. In France, fishing rights have these properties. In theory all the elements are present to reach economic efficiency in resowce allocation. However, the history and institutional or- ganization ofrecreational fishing in France leads to some problems: property rights are traditionally at- tenuated, which can be viewed as a heritage from the French revolution; the angler's lobbying proved efficient in leading to a very low level of fee implementation; the l94l law was modified in 1984 to provide better protection of rivers and a democratization of recreational fishing. From these follows, that in France angling is quasi-open-access. The fishing fee is very low and there are multiple forms of exemption. Indeed, 20o ofanglers are exempted. The national federation ofAAPPMAs (LJNPF) is making the democratic rule ofrecreational fishing a priority. The rule enforced by the UNPF is"fishing everywherefor everyone at low cost". The govemment, via the CSP, encourage the democratization of recreational fishing and made it a goal in the law change of 1984. Owners of fishing rights are encouragrd to give-up their rights. It is unusual that the rights are sold to the AAPPMA. In 2000, the government provided a legal framework for giving-up property right in a decree that specifies the way rights can be given free of charge toAAPPMAs.

AAPPMAs also set agreements between regional fed- eration. By paying a low additional fee, an angler can fish in all the department or the entire region. Recently, national agreements have arisen. They are reciprocal agreements which allows a recreational fisherman who pays the reciprocal fee to fish almost everywhere in France. However, a few AAPPMAs are opposed to this system, which they find incompatible with an "environmentally friendly and responsible recreational fishing". This institutional framework leads to a non- optimal situation from an economist's point of view.

The economic problem associated with property rights attenuation

In France, fishing is accessible to everybody, with al- most no restrictions, at a very modest price. Thus, recreational fishing has become a quasi-public-good Auauua pottcy AND pRopERTy RiGHrs /N FRANcE .' âN EcoNoMtc AppRoACH in most regions of France. The attenuation of prop- erty rights is the source ofthree types ofexternalities that negatively affect the angler's welfare. An accept- able definition ofan extemality is given by Pigou (1920) as an effect imposed by an individual A on the welfare of an individual B, without compensation. For recrea- tional fishing, the three main extemalities that can be identified are the following :

two externalities among anglers taking the form of stock externality and congestion, externality between anglers and farmers taking the form of pollution and loss of environmental serv- ices.

Externalities among anglers arise because a private good (recreational fishing) is institutionally tumed into a public good. As there is almost no cost for recreational fishing, it becomes an open-access resource.

Since [START_REF] Hardin | The tragedy ofthe commons[END_REF] we know that open-access re- sources are subject to "the tragedy of the commons".

Because fishing is free, anglers enter the fishery until marginal welfare per angler is zero. This phenomenon has been modeled by Fisher and Krutilla (1972) for recreational activities in general and more recently, for recreational fi shing by Anderson (1 993).

The stock externality should be limited by imposing limitations on the number of anglers. Economic efficiency is attained when the marginal willingness to pay for an additional fish equals the marginal stock extemality. There is such a point, associated with a number of anglers. Effrcient policy would tend to reach this point.

Congestion problems are very similar to stock exter- nalities. These are also related to the high number of anglers on the rivers. There is little information on the impact of congestion in France. If we consider that recreational flrshing is an activity where anglers look for calm and solitude, then we expect congestion to be present. Congestion affects anglers in the same way as stock extemality.

It is likely that recreational fishing does not affect the stock levels in France. However we know that for some stocks (e.g. spring salmon) recreational fishing represents a real threat. Surveys made by AAPPMAs tend to show the absence ofcongestion on French rivers, at least locally. A national survey conducted in 1990 revealed that for lÙYo ofthe anglers congestion was a reason to limit their visits (ISL, 1990). Moreover it is noted that for some periods like opening-day, public holidays or weekends, congestion is evident. Anglers can be considered as free riders. Because an- glers are not paying for the property rights, landowners (mostly farmers) are not incited to account for them.

If landowners could trade their rights, they would be encouraged to improve fishing qualify and to preserve the environment. Anglers are not the only users, by far, ofrivers and the associated amenities. Anglers alone cannot manage the issues of drinkable water, loss of biodiversity, floods, coastal pollution, etc. Because transaction costs are too high and water is a public good, these extemal effects deserve specif,rc public policies. In France and especially in Brittanya agriculture is very intensive. Briton agriculture is mostly intensive animal growing which releases to the environment, and then directly to the riverss, huge quantities of nitrates, phosphates and heavy metals. However, in some areas these effects are local. For these we be- lieve that anglers action can have an effect because transaction costs are low. Agriculfure areas along the rivers is a problem to recreational fishing in terms of access and scenic nature ofthe rivers. The cropping of com for cattle feeding is threat to the rivers, in terms ofpesticide release into the rivers and bank erosion.

Property rights enforcement could reduce the exter- nalities associated with the open-access situation. It works if transaction costs are low, which is the case for the latter extemal effects.

Ideas to conciliate theAAPPMAs system and economic efficiency

We have seen that property rights do exist but are attenuated. Recreational fishing is therefore a common pool resource subject to Hardin's tragedy of the commons. Then, anglers can be viewed as free riders and this leads to a non optimal situation with negative ex- temalities that lower anglers' welfare.This sifuation can be solved by simply enforcing well-defined property rights. Economic literature has largely shown the close relationship between property rights and externalities @emsetz, 1967).

Coase (1960) has shown that well-defined property rights are a sufficient condition to reach economic ef- ficiency ifthere are no transaction costs. This result is valid whatever the initial distribution of property rights.

Coase suggestion's is that bargaining for property rights will lead to the efficient allocation ofresources.

The hypothesis of no transaction costs limits the ap- plication of Coase's solution.

In France everything conceming rivers and recrea- tional fishing, relies on public policy. Environmental JULIEN SALANTÊ tuo Pmuppt LE GIFFE policy is based on two majorpolicies. Firstly, the wa- ter policy to deal with pollution. A public policy is necessary, due to high transaction costs at the scale of the water basin and the public nature of water. Sec- ondly, agricultural policy uses many specific tools.

Agri-environmental measures (European common ag- ricultural policy) and territorial farm contracts (French policy) are policies that can affect the riparian agricultural parcels. They take the form ofgrassland premiums, subsidies to conserve wetlands and to clean river banks. Since market transaction-costs are low for these amenities, coasian bargaining could be more efficient than a costly public policy.

Recreational fishing policies are based on many measures. The most important measures are closure periods, size limits, daily bag limits, technical restrictions on bait and hooks, a TAC for salmon and stock enhancement. These measures do not affect the level ofcongestion on the French rivers.

Worse, these measures are probably useless to pre- serve stocks (Thibault,I 9 92) and ar e r adic al regard- ing angler's welfare. Restrictions imposed on fishing periods are necessary during spawning periods but sometimes they are extended widely into traditional fi shing periods.

However, we think the system can be maintained and improved. At present, anglers are paying a fee for the entire year. Instead they might be paying at the margin i.e. for each additional visit. In this way, fishermen will limit their visits, which will have posi- tive effects on congestion and probably stocks. It is also possible to imagine a system to restrict trips during high congestion periods like public holidays or the opening day. This could take the form of quotas ofanglers or lotteries like in Spain. Indeed, lotteries match the AAPPMAs democratic system.

For several types of local external effects where transaction costs are low (bank cleaning, creation of environmental buffers, conservation of wetlands, etc), we suggest property right bargaining between AAPPMAs and farmers.

It is noted that the transition period between the ac- tual system and a more sustainable one is a problem.

At this stage, anglers will pay for property rights but rivers will only improve in the longer term. For this reason, we think that anglers will be reluctant to pay.

Finally, we need to control income effects. Indeed strong income effects are not compatible with the democratic rules of AAPPMAs. The implementation ofsocial pricing looks like an appropriated solution.

4 Brittany is the western part of France. lt has reputation for its beautiful rivers in which one can fish trout or salmon.

5 There is no phreatic in Brittany due to the granitic susbstrate. Economic research can contribute to the policy de- bate by quantifying the welfare losses linked to these extemalities. This can be done by measuring the de- mand functions using contingent valuation method, travel cost method and random utility models. Indexing demand functions on indicators of environmental quality (agriculture), congestion and stock level allows for the calculation of welfare variations linked to the improvements. In this way, economic research can give arguments for the implementation of new policies.

AneuNa pottcy AND pRopERTy R/6Hrs /N FRTNcE : AN EcoNoMrc AppRoAcH

  a 2 ln French: Conseil Supérieur de la Pêche (National Fishing Council).

3

  ln French: Union Nationale pour la Pêche Française. Paon 98 -?"i Iloru.o Rx:nutnoi,t,rt. histunc {iurr'tttr':a<:r. 21 -24 lt[,tv 2002, Nonturnt ']i;ntutottt., .4 ofl'nlt.ts.

  SALANTÊ AND PHtLtppE Lr Gorre ConclusionWe have shown fishing rights are haditionally released for free in France. The institutions in charge ofrecreational fishing management orgarizethe attenuation of property rights. The results is that recreational fishing is institutionally tumed into a public good. Three types ofexternalities arise from this situation : stock extemalities, congestion and pollution. Property rights bargaining could improve the situation. Anglers would pay more for good quality fishing and environmental improvements. Moreover, by reducing the number of anglers, it will cope simultaneously with congestion

J"r Wonln llriurr^r toN^r. Flsuri\6 CoNlrimulcr.. 2l -?4 lv{av 2002. NoxrnËRN Ii:RRnoky, AlJSmi\r-l-A.- P,qer 99 JULTEN and stock externality.


Yves Léon
email: yves.leon@roazhon.inra.fr

The evolving role of agricultural economists in policy-related research in the rural economy

Introduction

INRA • ECONOMIE

Recent advances in spatial economics and endogenous growth theory have brought to the fore a number of issues relating to regional development and town-and-country planning in Europe. At the same time, damage done to the environment by human activities is giving cause for concern, while the growing numbers of city dwellers want to be able to enjoy well conserved countryside. Consequently the changes occurring in rural areas have become a major challenge for many countries and regions, either because such areas make up a large part oftheir territory or because they contain scarce resources that should not be wasted.

Agricultural economists should be at the forefront of the scientific community in understanding what is currently at issue in the countryside, analysing the economic phenomena involved and helping to define the right policies. Is this what they are doing? My answer to this would be circumspect. For one thing, it seems to me that comparatively few agricultural economists today are particularly interested in the economy of rural areas, whereas geographers and sociologists have long been active in this domain. But then again, agricultural economists seem to me to be very well placed to provide a whole new perspective on countryside issues. The reason why our profession is so little involved in analysing the rural economy is most certainly because agriculture has long dominated many rural areas of Europe, leading agricultural economists to specialise in the study of agricultural production and of factors related to markets and trade, and more generally to take a sector-based view. But it is also because it is difficult to work space into economic analysis, outside of research into the urban economy (de Janvry, [START_REF] De Janvry | CIADT : de nouvelles orientations pour l'aménagement du territoire[END_REF]. That said, recent decades have seen substantial changes in the economic and social organisation of rural areas, with farmers and farming ceasing to be at the centre of country life. Agriculture is no longer the be-all and end-all of country life as it once was and it is becoming urgent to analyse the rural economy in its true dimensions and complexity.

This paper discusses what agricultural economists might contribute to this huge undertaking both by way of a positive approach and in helping to introduce efficient rural development policies. This will involve analysing directions for research in an area that is still underexplored by agricultural economists, so that they can make the best use of their present skills or develop new ones, among other things through working with specialists in other areas of the social sciences. Obviously an option like this entails risks in that it may mean moving away from mainstream economics and measuring up to other disciplines. This paper will refer above all to work done in France and subsidiarily elsewhere in Europe. This rather continental approach will probably be a little out of step with the concems of UK scholars, which should make discussion of it that much more lively!

The paper is divided into three parts. The first of these examines the theoretical and conceptual issues facing those agricultural economists interested in the rural economy. The second covers avenues of enquiry now open, and the third contains some thoughts on the direction that future research might take.

Assertions and assumptions about the rural economy and rural development

Unlike agriculture, the countryside is not an easy idea to grasp. Accordingly, any analysis of the rural economy runs up against a problem of delimiting the object of enquiry. , 2001). People's impressions of the areas they live in may therefore be very different from the statisticians' classifications, for all their objectivity. Any definition of rural areas therefore runs the risk of being an oversimplification. But it is a risk that bas to be taken.

The economic, demographic and residential changes now taking place show how transient the boundaries of what used to be the countryside are. Broad belts where farming still goes on now lie within the outer boundary of urban areas and seem destined to evolve pretty much in step with the city at the centre of the periphery they form. This obviously does not hold for the less densely populated areas well away from cities and whose future course seems to be less dependent upon strictly urban change. Under the existing zoning scheme in France, such regions make up the 'predominantly rural space' which is home to 23 per cent of the population and covers 69 percent of the territory [START_REF] Bessy-Pietri | Recensement de la population 1999. Evolutions contrastées du rural[END_REF]. Of course, areas which are geographically rural or whose inhabitants, as we saw above, feel they live in the countryside are not confined to these ' autonomous' rural areas, but these rural areas do have characteristics that warrant special attention from analysts and politicians alike and it is to these areas that I shall be referring.

The countryside is defined here, then, on a geographical basis with no prior assumptions about the diversity of the economic structures or of the sociological or political realities to be found there. This choice may be challenged because it situates rural areas by opposition to urban areas [START_REF] Saraceno | Recent Trends in Rural Development and Their Conceptualisation[END_REF] and so strips them of a part of their supposed identity. But is there really any other choice in today's Europe, where everything seems to be moving towards urban agglomeration, albeit with some national or regional colouring? It is a point that is certainly worth talking about and which may differ in scope from one discipline to another. Rural sociologists and political scientists are concemed by the social changes taking place in the countryside with the decline in the number and social and political weight of farmers, the intermixing of population and the reconstruction of social ties and networks of influence. In a context like this, does the concept of 'rurality', which postulates that there are mechanisms that give rural areas their own structure, have any explanatory value [START_REF] Marsden | Constructing the countryside[END_REF] and can it serve as a vector for a European policy [START_REF] Richardson | Discourses of Rurality in EU Spatial Policy: The European Spatial Development Perspective[END_REF]? It is noteworthy that rural geographers, who are increasingly interested in political behaviour and social changes, are undecided which approach to choose and seem to be drawn more towards getting a grasp of the big picture and developing an analysis that emphasises the connections between cities and the countryside (Bailly et al., 2001).

Where do agricultural economists working on the rural economy stand on this? Their position is not the only one, but generally they recognise the role played by outside economic, social and political forces in the economic restructuring of the countryside. Without going into detail about these forces, their presentation now being classical [START_REF] Blanc | La ruralité: diversité des approches[END_REF], it should just be recalled that international negotiations on world trade or on climate change have or will have repercussions for two functions of the countryside, the production of agricultural goods and foodstuffs, and the protection of the environment. In addition, the countryside's involvement in displacements of the workforce and in trade in goods and capital assets is actually a partly involuntary contribution to the economic polarisation and concentration of population that is going on in Europe. Lastly, changing lifestyles brought about by society's greater wealthmore leisure time, increased commuting and geographical spread of housing around urban agglomerations -give added importance to the residential function of rural areas.

As I see it, then, the economic analysis of rural areas must be conducted within a very broad framework, although that does not mean that the countryside is a residual space whose future is to be dictated by that of the major cities alone. Nor does it mean that a top-down approach is the only one possible. Quite the contrary, it seems particularly fruitful to conduct an analysis based on thorough knowledge of the economic, social and political mechanisms of local development and on an undcrstanding of the more general trends affecting rural areas.

The idea oflocal economy suggested by [START_REF] Saraceno | Alternative Readings of Spatial Differentiation: The Rural Versus the Local Econorny Approach in Italy[END_REF] emphasises the diversity ofrelations between different types of predominantly rural or predominantly urban spaces. This tool frees us from the single-track thinking whereby cities hold sway over the countryside. The EU Leader initiative may be seen as an empirical test of this tool in that it is designed to bring together the vital forces of a local community and to develop the dynamism of its networks in producing fresh initiatives.

This last remark brings us to the second objective in this section, which relates to the role agricultural economists can play in rural development. Beyond the work on theory or method that is the core business of our profession, it is clear that decision support is also part of our stock-in-trade. Consequently, for many of us, the more academic side of our work stands alongside an interest in economic policy analysis and specifically an interest in issues of rural development.

Can we try to specify what rural development is and what it represents for an economist?1

Historically, in many countries, rural development has been mistaken for the modernisation of agriculture, the restructuring of farms and the improvement of farmers' incarnes. This is still the prevailing view in the CAP Rural Development Regulation except for its Article 33 (Lowe et al. , 2002). And yet, the idea of rural development relates to much wider concerns. 2 For some commentators, agriculture is still central to the process of rural development because of the forward effects it provides (Midmore, 2003). For others, associating rural development and agricultural development is a non-starter, given that farming and other countryside activities are heading in separate directions [START_REF] Thomson | Agricultural Economies and Rural Development: Marriage or Divorce? Presidential Address[END_REF]. In France, rural development is viewed as a component of integrated local development and of regional development in the bill that is shortly to be tabled by the 'Ministry for Agriculture, Food, Fisheries and Rural Affairs' (Datar, 2003).

To my mind, rural development must relate to the core concept it contains, the concept of development. I therefore take the view that rural development must be tied in to development economics, that is, to the human dimension of economics. Accordingly, rural development cannot just be about analysing the economic growth of rural areas or the spatial distribution of activities located there, even if the theories and methods employed are of tremendous interest in understanding the mechanisms of development of the countryside.

Rural development is an economic and social project that must achieve the objectives pursued both by the people who live in the countryside and by society as a whole. If this is taken as a starting point, the objectives of a rural development policy should, I feel, relate to efficiency, equity and sustainability, which can be achieved by changing the behaviour of those involved.

Although efficiency has a precise meaning for economists and need not be defined here, it may be worth noting that the concept of territorial equity introduced here is about the requirement for everyone to have equal access to a number of facilities and services wherever they may live. Finally, sustainability is a key factor in any development project and is a chief concem of the actors of rural areas. The change in behaviour mentioned refers to the need to think of rural development as a shared project between the people who live in the countryside and the people who make the decisions about territorial planning and its economic and social cohesion. This change in behaviour must be reflected by a more collective approach to developmenl questions within rural communitics and by an understanding of the assets those communities possess in the form of human and social capital [START_REF] Ray | The EU Leader Programme: Rural Development Laboratory[END_REF].

This lengthy list of points to consider when dealing with territorial development reflects the complexity of the actual situation. This is a real challenge for agricultural economists, and one which is made that much greater by the diversity of situations found in rural areas whether in terms of their economic fabric, their endowment in resources or their geographical location.

Research on rural development should take a specific approach that makes allowance for the sheer complexity of the issues. There is little doubt in my mind that different disciplines must corne together to tackle a project like this, because only interaction by economists, geographers, sociologists and specialists in other areas of science can overcome the limits each discipline cornes up against. And so it is particularly important to have a clearer idea of what we, as agricultural economists, can contribute to this debate so that we can envisage working with people in other disciplines.

The spectrum of issues brought before agricultural economists by broadening their focus to the rural economy as a whole

Although a number of studies by agricultural economists can be used to provide a better understanding of how the rural economy operates, it has already been seen that our profession has done rather little work in this specific domain. Thomson is highly critical of this and even speaks of underdevelopment of this line of enquiry in the UK (2001 ). 3 It is a point of view that might be echoed for France. And the same might be said of other European countries with the notable exception of Italy, where agricultural economists have long included the territorial dimension in their work, probably because non-agricultural activities have long been spread around regions where farming was important and because of the significance of small and medium-sized cities in the country's make-up [START_REF] Saraceno | Alternative Readings of Spatial Differentiation: The Rural Versus the Local Econorny Approach in Italy[END_REF].

But regardless of how important it may once have been, the historical argument no longer holds, given the current changes which are making rural areas more important again. This observation, which calls for us to think about future lines of investigation, should not cause us to forget that a number of valuable studies have already opened up promising avenues of research into the rural economy. What might be thought remarkable is that these studies have been built on foundations specific to our discipline. This shows how the theoretical premises of economic analysis and the methods already in use can provide an understanding of certain aspects of the rural economy. Here are three examples by way of illustration.

The first approach involves some measure ofreflection on agricultural policy, which broadens out to questions about connections between the environment and agriculture and then leads on to a detailed analysis of the rural economy and the prospects for it. This is now a common opening gambit. It is a classical approach in agricultural economics looking into the consequences of agricultural practices for the environment where the real costs of production are not internalised. The pressure of farming techniques on natural resources grows as those techniques progress and is often compounded by signais from the agricultural policy. At this stage, the perspective broadens from one of production economics to resource-based economics, encompassing all of the costs engendered by farming in a single fonction (van Huylenbroeck and Whitby, 1999). While farming may have a negative impact on the environment, it is recognised too that appropriate fam1ing practices which are more respectful of resources like water and landscape do maintain or produce public goods that are increasingly sought after. This is the direction taken by current thinking on multifunctional agriculture and on its contribution to the protection of rural amenities [START_REF] Dupraz | Production de biens publics par des ménages: une application à l'offre environnementale des agriculteurs[END_REF]OECD, 2001). Extension of such thinking in terms of agricultural policy can be seen in the measures adopted by the Regulation on rural development destined to implement the second pillar of the CAP.

The second stage in this line of enquiry is Jess common in that it seeks to identify from the foregoing analyses what the consequences will be for rural development. This approach goes beyond an examination of relations between farming and resources in terms of production, to consider how agriculture fits into the countryside. The premises are unchanged but agriculture is now seen instead as an activity that complements other activities or that is in competition with them for the use of rural resources [START_REF] Mahé | L'avenir de l'agriculture bretonne: continuité ou changement? Rennes: Apogée[END_REF]. Each activity is classified according to its contribution to rural development in view of the factors determining its location, such as the presence of localised inputs, internai or sector-based scale economies, or proximity externalities. Activities can then be arranged by type depending on their potential contribution to the rural economy. Proponents of the approach claim that farming, the remnants of the quarrying and mining sector, primary product processing and the leisure sector provide a solid foundation for a rural development policy and one on that can be built on by the service activities they induce and the resulting residential demand. A cumulative mechanism may develop because of the density of the economic base in relation to local resources and to the impetus effects engendered by the base and so bring about the development or decline of the area in question. Although the initial endowment in resources is an essential factor, collective action and economic policy do sometimes make a difference [START_REF] Mahé | Politique agricole : un modèle européen[END_REF].

My second example relates to a quite different approach derived from the spatial economy and which may or may not be combined with economic geography. Here, it is no longer their knowledge of the mechanisms of agricultural production that underpins the contributions made by agricultural economists, but their interest in areas that are often overlooked by spatial economists, who usually concentrate on the urban economy. In addition, agricultural economists canuse their knowledge of the rural environ.ment, of local labour markets and of the workings of traditional activities in rural areas [START_REF] Errington | Tracing Local and Global Linkages in the New Rural Economy: The Economie Footprint of Small Towns, contribution to an international conference[END_REF]. These comparative advantages apart, they are in direct competition with spatial economists.

The value of these analyses lies in the way they handle rural areas with the tools of spatial economics and identify the network of agglomeration and dispersion forces affecting those areas. This is the first stage in understanding the dynamics of the countryside. It sheds light on human commuting and relocation patterns and the movements of goods, services and capital that affect the countryside. A number of studies have been made of the relations between cities and the countryside and in particular the flows of labour between urban poles and their peripheral rural areas. The objective is to identify mechanisms to explain the reversai in the demographic trend that occurred in rural areas close to cities in the final decades of the 20th century and what that means for the economic future of these areas. Although models of location of activities in urban and periurban areas may be sui table for rural areas lying close to big urban centres undergoing a demographic boom, a great deal ofwork remains to be done to understand what the more remote, autonomous rural areas can expect from this historical demographic change which involves them little if at all [START_REF] Gaigné | Economie géographique et dispersion des activités productives : contributions à l'analyse de la localisation industrielle en zone rurale[END_REF]. [START_REF] Schmitt | Economie geography and contemporary rural dynamics : an empirical test on some French regions[END_REF] argues that employmcnt is the key variable of economic dynamism in autonomous rural areas and drives demographic change, while this relation of cause-and-effect is reversed in the case of rural areas within the ambit of cities. My own experience of investigating economic polarisation in an autonomous rural region of Brittany provides empirical evidence that employment is indeed a driving factor in that area (Daucé and Léon, 2002).

Other authors like Kilkenny, modelling the economic dynamics of rural areas, ponder how they can effectively address questions on rural development in economic terms [START_REF] Kilkenny | Transport Costs, the New Economie Geography and Rural Development[END_REF]. Economie models inspired by Krugman's work, although they have their limitations when applied to the rural economy, open up interesting avenues of enquiry into the role of corrective economic policies. There is for example the European policy for rural development which supports small cities to offset the effects of the trend towards urban agglomeration or, in opposition, CAP support for farmers which forces up land prices in the countryside and so may discourage the setting-up of non-farming activities. These two examples show what a special case rural areas are and argue for the construction of explanatory models that have to be more thanjust ' reconverted' urban models.

Finally, it seems to me that agricultural economists are in a position to make a major contribution to the evaluation of economic policies for rural development. This is an increasingly important field of activity at European, national, regional and local levels. Such policies are generally targeted at specific territories, which again leads agricultural economists to abandon sector-based approaches and to venture into the analysis of complex relations among the actors, activities and functions of rural areas. On this ground, which has been marked out by many disciplines, we are well placed to conduct an economic evaluation of policy effects. I emphasise the term economic so as to specify the content of our input as distinct from that of other disciplines also engaged in ex ante and ex post evaluations of rural development policies. The theoretical and methodological apparatus at our disposai allows us to make ex ante judgements of the relevance and suitability of these policies and to determine ex post, to some extent, in what ways and to what extent they have affected the actors and territories concemed.

Our involvement in the design of policies by the European Union, by central govemment or local authorities is essential for a proper appreciation of the challenges that such policies entai! for society. The same holds for our involvement in evaluations commissioned by the same authorities, if only to compare our viewpoint with that of the actors in these policies and to assess our contribution against that of our colleagues in other disciplines. However, the scope of this involvement may prove too restrictive, being boxed in by the objectives set by the institutions commissioning these evaluations, as [START_REF] Thomson | Agricultural Economies and Rural Development: Marriage or Divorce? Presidential Address[END_REF] points out. When evaluating the effects of rural development policy, agricultural economists should exploit their comparative advantages in economic analysis and provide a judgement of the impact of the policy that goes beyond a simple assessment of the policy's interna! efficiency and effecti veness.

To pass judgement on the relevance of this type of policy, which is reflected by transfers in favour of rural areas, economists possess a theoretical framework on the relevance of a corrective policy designed to make good market failures. Location theorists often take agglomeration to be the spatial dimension of efficiency, meaning that a territorial development policy such as the rural development one, used as an alternative to the market, would be inefficient a priori. This assumption goes to the heart of current discussion on the relevance of regional policies, particularly of European regional policy [START_REF] Martin | Can Regional Policies Affect Growth and Geography in Europe?[END_REF][START_REF] Braunerhjelm | Integration and the Regions of Europe: How the Right Policies Can Prevent Polarization[END_REF]. The debate is still ongoing. If allowance is made for imperfect competition because of space, it cannot be maintained that the agglomeration of activities is a social optimum [START_REF] Ottaviano | A qui appartient l'espace rural? Enjeux publics et politiques[END_REF]. The same type of analyses are being conducted on European rural development policy but need to be taken further if they are to provide a basis for showing that the policy is economically relevant [START_REF] Gaigné | Economie géographique et dispersion des activités productives : contributions à l'analyse de la localisation industrielle en zone rurale[END_REF].

Analysis of the impact of such policies is still found wanting in terms of theory and the models for quantifying the impact of public support for rural development are still to be constructed, even if some interesting attempts are currently being made [START_REF] Charlot | Agglomération, bien-être et politiques régionales, working paper[END_REF]. Although less ambitious, attempts to evaluate the effects now yield interesting evidence about the structure variables conditioning economic performances of regions where the policy is operative. One big unsolved question is how to measure the actual impact of the policy under study. Because there is no way of knowing how rural areas receiving support would have performed without the policy, two methods are employed. One consists in comparing the performances of regions where the policy bas been introduced with the trends recorded before its implementation. The other compares the performances of regions receiving support with comparable but unsupported regions. The latter method involves allowing for selection bias related to the choice of supported areas, which is a prior condition for building more elaborate models. This approach has been applied by [START_REF] Schmitt | The economic effects of the European program of rrual development in Burgundy: Allowance for selection bias[END_REF].

This section has covered some highly promising aspects of the involvement of agricultural economists in rural economics and rural development but it has also brought out the complexity of the issues involved. This implies that more and more varied approaches should be adopted. The final section, then, presents a number of questions worth exploring, some lying on the boundaries of our discipline.

Future contributions from agricultural economists: a disciplinary versus a multidisciplinary research option?

Although there is no denying that agricultural economists contribute to a renewal of the approach to questions about the rural economy and rural development, the few examples chosen suggest that there are many conceptual and methodological difficulties to be overcome. There seem to be two obvious ways of setting about this. We need both to look more closely at the concepts specific to economics and, at the same time, to engage in discussion with other social scientists working in this domain. In other words, we have to strengthen the anchor points of our own discipline while accepting that our scientific position is open to debate. Let me illustrate this with two central features of rural economics and rural development: territory and actors. Clearly there is a tie-in with the research of geographers and rural sociologists, who have similar concerns to ours.

Territory cannot be easily introduced into economic reasoning because of the need to find some way of allowing for the loss of efficiency it engenders in allocating resources. However, the programme of work for an economist specialising in rural economy involves analysing the interaction between the economy and space, and this is a matter that has to be addressed. I have already gone over what spatial economics and economic geography can contribute to this. The big issue is probably the restructuring of the countryside, which is carried out in counterpoint to polarisation around major cities. While economists observe and analyse this through patterns of human movements and flows of goods and services [START_REF] Cavailhès | Change in the French countryside: some analytical propositions[END_REF][START_REF] Royer | Quelques tendances affectant la répartition spatiale de la population, de l'emploi et de la valeur ajoutée en France métropolitaine, entre 1982 et[END_REF], it is a question that has been debated among rural sociologists and geographers in the UK and France for some years now [START_REF] Bodiguel | Campagne française, campagne britannique[END_REF][START_REF] Marsden | Constructing the countryside[END_REF]Hoggart and Paniagua, 2001). Does the countryside change only through the influence of economic forces and movements of population or does this transformation involve a change in social structures and relations between individuals? This is a familiar question for geographers, historians, sociologists, and legal and political scholars, and is also of concern to economists who will find food for thought in the explanations proposed by other social scientists confronted with similar questions although they corne to them by different routes. For economists, the view point may be the significance and role of collective goods produced in the countryside and consumed by its residents or visitors. The countryside contains a wealth of public goods such as rivers, landscapes, paths, natural and cultural amenities. Changes in production processes and particularly in farming processes and in rural ways oflife lead to a reduced suppl y of these goods despite increasing demand for them, often from people who have no part in producing them. These goods may even be deteriorated by intensive farming practices. Can such goods be included in the agricultural production fonction and how is multifonctionality to be dealt with?

This typically economic objective of modelling the production fonction of an activity producing goods of different sorts may also lead us to investigate competition between different land uses and to think about the relative importance of the fonctions of production, residence and conservation of natural resources that the countryside provides (Daucé and Léon, 2002;Perrier-Cornet, 2002). Can control of the land and of rural amenities, which is usually exercised by farmers and the traditional actors in the countryside, be challenged by newcomers in the name of development of the residential fonction? Economists, legal scholars, sociologists and geographers challenge their rights of ownership and their use of certain public goods as well as their political and social status (Soulard, 1999). Thus, the reserved or sometimes hostile attitude of some farmers to the incentives for environmentally-friendly practices may have social or political as well as economic causes. Likewise, economists also study the behaviour of those actors who challenge the rights and status of farmers by evaluating their willingness to pay for public goods which they wish to consume in the countryside (Hoggart and Paniagua, 2001).

Territory and actors are still closely tied when it cornes to rural development policies. In economic terms, such policies are designed to alter the distribution of people and of activities supplied by the market. As economic polarisation is held to be detrimental to the countryside, policy proposes to reduce the inequalities engendered by concentrating the most productive activities and the most skilled jobs in just a few areas and so promote the introduction of a socially preferable equilibrium. However, there are no clear reference points for defining this type of geographical equilibrium. A number of questions are raised [START_REF] Gérard-Varet | L'Etat et l'aménagement du territoire[END_REF]. In terms of efficiency, endogenous growth models show that growth can occur in parallel to concentration, suggesting that territorial policies are of limited value [START_REF] Jayet | Enjeux économiques de l'organisation du territoire[END_REF]. However, work is still continuing on defining the criteria of efficiency in a complex spatial economy. Spatial equity, which is one of the main arguments in support of the rural development policy, also raises a number of problems because it cannot be unambiguously defined. Gérard-Varet and Mougeot report that it is far from self-evident to transpose vertical concepts of equity to territories. Such 'horizontal' equity does not automatically promote fairness among individuals within the relevant territories, even working with the equal opportunities principle suggested by Rawls. This raises the matter of what the target of the rural development policy is to be. Should the policy be aimed at territories or at actors?4 This type of policy also posits that agents are comparatively immobile. If they can move around, how can a relevant geographical criterion be found? It then becomes essential to analyse factors that reduce mobility. This relates to the economic costs of relocation as well as its social aspects in terms of the severing of family and social ties that moving house entails. Sociologists must allow for these factors if we are to achieve any understanding of certain labour markets, in particular rural ones, and the failure of certain policies based only on the differences in wage levels between regions.

It can be seen, then, that human and social factors are essential considerations if we are to go beyond the bounds of a strictly economic analysis in dealing with the rural economy. Here is one last example to show this. Economists generally agree that one of the keys to rural development lies in enhancing the value of resources specific to the countryside and many studies have been designed to identify these resources and their distinctive characters in terms of economics. The first notable character, and probably the most important one for endogenous development, is the connection with the territory, which ensures that the resource in question will stay where it is. It has been seen that rural areas have resources of this type, particularly natural resources. Rural areas may also enhance the value of their specific human and cultural resources. Here would be the place to speak of the assets that rural communities can take in band to promote their development. [START_REF] Ray | The EU Leader Programme: Rural Development Laboratory[END_REF] economists cannot be indifferent to it either. I feel that they hold there the ultimate reason as to how it is that, under comparable economic circumstances, some regions win and others lose.5 (2002) considers that successful rural development derives from close integration of the natural, artificial, human and social capital endowments of the regions in question. Whereas agricultural economists commonly include the first three of these forms of capital in their analyses and models, this is perhaps less true of social capital, based as it is on the presence of institutions, of interpersonal relations and of networks, which have only corne in for economic scrutiny relatively recently. Admittedly, social capital is a notion with no hard and fast definition as yet and is still a matter of controversy even among sociologists [START_REF] Lévesque | Le concept de capital social et ses usages[END_REF][START_REF] J6hannesson | Coping with Social Capital? The Cultural Economy ofTourism in the North[END_REF]. Economists are working to make it into an operational concept by considering that the intensity of relations within a group produces positive externalities that can be used to further the group's collective objectives [START_REF] Kostov | Integrated rural development. Do we need a new approach? 43-57[END_REF]. Where there is a connection between the organisation of people and the territory, such social capital becomes non transportable and forms an organisational asset of the region [START_REF] Jayet | Quelle organisation économique des espaces ruraux ?[END_REF].

Sotte

Conclusion

To end this paper in a slightly provocative way I am tempted to say that 'the rural economy is too serious a business to be left to the economists alone'. My aim in saying this is, of course, to stir up debate on the topic. I hope that these few examples have shown what agricultural economists are contributing to the debate about the future of the countryside. This contribution is far from negligible, but it is a pity that so few members of the profession have taken up the challenge. The countryside has a considerable role to play in balancing out increasingly urbanised European societies. This role obviously depends on the demands that society makes of the populations living in the countryside, but also on how these populations act or react so as to promote their own interests and wishes. It is exciting work unravelling the tangle of interactions among the various actors.

Even from the standpoint of economists with their premises, their theories and their methods, the human factor has to be taken into account if we are to understand how rural areas operate.

I have tried to identify potential common ground for specialists from various disciplines and the benefits that economists can gain from exploiting the output of rural sociologists and geographers. The demonstration is incomplete and I feel I have only been scraping at the surface. The important chapter on methods has been largely overlooked because of lack of space, while analysis of the methods of geographers, for example, shows just how closely allied our concems are in this respect (Bailly et al. , 2001). For want of sufficient knowledge about the other social sciences analysing the rural economy, I have not really gone into a comparison of our respective theoretical premises. Much, then, remains to be done in exploring what could be a multidisciplinary approach to this field of study, but I do feel that this is the way forward.

  While each of us intuitively understands what is or is not rural, closer investigation of what the concept involves soon shows that it varies widely with objective geographical and economic factors as well as with historical and political traditions specific to a country or region. A recent survey by the CREDOC in France on 'the French and the countryside' showed just how widely ideas

on this matter differed. When asked 'Do you think you live in an urban area or a rural area?', 48 per cent of respondents who answered they thought they lived in a rural area were actually classified by the national statistics office (INSEE) as living in an urban pole or a periurban district (CREDOC

  referred to the European Leader programme as a 'laboratory for rural development'. To my mind, this sociologist's viewpoint identifies exactly what everyone concerned with rural economy is looking to promote: the endogenous forces whose synergy can sustain development projects. If sociologists, political scientists and geographers are eager to discover what alchemy is at work in this laboratory,

This section restates a number of the conclusions I drew from the AEEA

Ancona seminar(Léon,

2002). 2 See Arzeni et al. , 2002 for a recent discussion ofthis concept.

For a continental observer this opinion appears a little excessive given the number ofUK universities and research centres that have been working on this for many years and the standard of their output.

Actors may be chosen as beneficiaries of the policy to change the distribution of income within the terri tory.Dluhosch (2000) points out the difficulty with this approach which assumes there is some norm for income distribution and that different distributions can be compared objectively.

To use the expression of[START_REF] Benko | Les régions qui gagnent. Districts et réseaux: les nouveaux paradigmes de la géographie économique[END_REF].


Common ash (Fraxinus excelsior L.) is the largest tree in the genus Fraxinus and at maturity (90-120 years) it can reach 20-35 m (maximum 40 m) in height. The mean stem diameter varies from 30-70 cm (maximum 150 cm) in adult specimens. The crown is irregular with massive branches, elongated in forest stands.

Common ash is wind pollinated. Flowering starts at 15-20 years on single trees and at around 30 years within stands at irregular intervals. The breeding system is polygamous, ranging from male to female individuals with hermaphroditic intermediates. Morphologically hermaphroditic individuals are often predominantly male or female. Interannual variation in sex expression is observed. The fully developed seeds start to disperse by wind in the autumn. Seed dormancy usu-

Fraxinus excelsior

EUFORGEN

These Technical Guidelines are intended to assist those who cherish the valuable ash genepool and its inheritance, through conserving valuable seed sources or use in practical forestry. The focus is on conserving the genetic diversity of the species at the European scale. The recommendations provided in this module should be regarded as a commonly agreed basis to be complemented and further developed in local, national or regional conditions. The Guidelines are based on the available knowledge of the species and on widely accepted methods for the conservation of forest genetic resources.

Common ash

Technical guidelines for genetic conservation and use

Biology and ecology

ally lasts for two winters but can last for up to six. Stored seed requires combined warm-cold stratification to germinate.

Common ash requires a rich soil and tolerates a pH as low as 4.5, but prefers soil above 5.5. It is highly tolerant of seasonal water-logging and favours floodplain forests. It is also a typical species of slopes and ravines, growing in association with other characteristic species such as maple, lime and elm. Although dormant trees are very cold hardy, the young shoots are sensitive to frost.

Common ash exhibits intermediate properties between a pioneer species and a permanent forest component. Although dispersal and natural regeneration are efficient, the competition ability of the species is only strong when the ecological requirements are met.

Vegetative regeneration is strong after coppicing.

The natural range of common ash covers most of Europe from the shores of the Atlantic Ocean in the West to the Volga River in the East, with the exclusion of the most northern and southern parts. The northern limit of the natural range is about 64°North in Norway, the southern margin reaching 37°North in Iran. In mountainous areas, common ash is found in the Pyrenees at 1750-1800 m above sea level and in the Swiss Alps at 1630 m. In Asia (Iran), it can be found at much higher elevations of up to 2200 m.

Of the four different ash species growing naturally in Europe, common ash is the most important commercially. Despite the high demand for this quality timber, only a few European countries have gene conservation or tree breeding programmes in place for this species.

Common ash timber is hard, elastic and withstands pressure, shock and splintering. It is used mainly for tool handles, and for sports equipment such as hockey sticks, oars and hurdles. It has a straight grain and there is little distinction between sapwood and hardwood, making it very valuable for furniture, veneer and flooring. The formation of "black heart", a dark stain of the hardwood, can occur in mature trees. This varies within and between individual trees and different sites and reduces the economic value. Ash bark and leaves are astringent and the leaves are used in modern herbal medicine for their laxative properties.

Distribution

Importance and use r Fraxinus excels mmon ashFraxinus excelsiorCommon ashFraxinus excelsiorCommon ashFraxinus excelsior

The genetic variation of a species, both within and between populations, is influenced by many factors. The mating system, pollen and seed dispersal, role and successional stage in forest ecosystems, site conditions and historical influences such as colonisation patterns after the glacial periods of the Quaternary are particularly important. Two types of genetic variation can be distinguished: (i) adaptive variation (i.e. enabling adaptability) and (ii) a priori neutral variation (i.e. not affected by natural selection). Adaptive variation, expressed in the phenotype in response to natural selection, has been investigated through provenance and progeny trials. These studies revealed that variation between families within provenances/ populations was generally as high as variation between provenances/populations. Phenological traits, including the date of bud burst and set, displayed geographic patterns on a large spatial scale, whereas growth and form, which are influenced by soil and competition conditions, varied at the local level. The existence of different ecotypes, (i.e. floodplain, hillside, slope and limestone ecotypes), has never been proven by progeny studies.

Chloroplast DNA data used to investigate neutral variation suggests ice age refuges in the Iberian Peninsula, the Alps and/or in Italy and in the Balkan Peninsula. This result is in agreement with fossil pollen data and the postglacial re-colonisation of Europe from these refuges. Nuclear DNA markers reveal levels of intra-population differentiation similar to other Noble Hardwoods such as chestnut, elm and walnut, but higher than is found in oak and beech. High differentiation was particularly observed between populations in southeastern Europe and in northern central Europe, indicating the high conservation value of ash genetic resources from these areas.

On the European scale, common ash is not an endangered species. However, the natural range and area of ash forests has decreased during the last 4000 years as the area of agricultural lands has increased. Silvicultural methods have promoted common ash in the last 30-40 years due to the high economic value, supporting natural regeneration, planting and thinning.

Common ash genetic resources are threatened by deforestation, loss of suitable habitats, unsustainable exploitation and improper management (i.e. uncontrolled transfer of reproductive material), natural climatic changes, global warming, air pollution, competition with other species, pests and game damage. These pressures could lead to population extinction. Despite the high regeneration potential, the reproduction of some valuable autochthonous populations is not ensured, and the health status of mature stands in some countries has deteriorated significantly in recent years. Therefore, common ash is considered to be threatened at the population level by most countries.

Threats to genetic diversity

Genetic knowledge ior Fraxinus exce

Common ashFraxinus excelsiorCommon ashFraxinus excelsiorCommon ashFraxinus excels

Genetic conservation aims at ensuring continuous survival and adaptability of the target species. These objectives are met when the Multiple Population Breeding System (MPBS) is applied. Ideally in MPBS, a breeding population is subdivided into subpopulations which are then grown over a wide range of site conditions.

In each country where common ash is found, an inventory should be undertaken to define the geographical distribution of the species, conservation status, threats and potential use patterns. Ecogeographic zones (provenance regions) should be delimited according to climatic variation, topography, soil and vegetation. Trees are generally best adapted to the ecological conditions of the region where they evolved. Therefore, local material should be used for plantations wherever possible, unless otherwise recommended as the result of data from provenance trials.

To ensure the adaptive potential of Fraxinus excelsior in Europe, it is recommended that two complementary gene conservation networks of populations are established, specifically: (1) a network of 20-30 in situ populations throughout provenance regions; and (2) a network of ex situ populations (progeny trials, provenance trials, collec-tions). Whenever possible, in situ conservation activities should be undertaken jointly for other Noble Hardwoods.

Where common ash occurs in large populations in a country, in situ conservation is sufficient, with the selection of up to three gene conservation populations/ gene reserves of 5-15 ha in size, with at least 100 flowering trees in each provenance. A high density of in situ gene conservation populations should be established in Southeast Europe, especially in Romania and Bulgaria, which have been colonised by populations from different ice age refuges. In these regions, neutral genetic markers show high differentiation among populations, suggesting that they may have different potentials to cope with future climatic conditions. Specific conservation efforts are also recommended in northern central Europe, due to the high level of differentiation between populations in southern Sweden, although the historical origin of this differentiation still needs to be verified.

In situ gene conservation populations need to be managed to increase their adaptive potential by ensuring the natural regeneration of the target species, creating multi-age structure and habitat diversity, and increasing generation turnover.

To conserve an even-aged mature stand in situ, parts of the population should be opened (thinned or cut in narrow strips of 15-30 m width) to create conditions for natural regeneration. Preferably, this should be undertaken in the year following the mast, when maximum seed is produced by the stand. An area adjacent to the gene reserve could be set aside for natural regeneration, and could later be incorporated as part of the reserve.

To promote regeneration in clear-cut strips, randomly selected, abundantly flowering seed trees should be left. If the population consists of some stands or groups of trees of different ages but there is no regeneration, the oldest stands or groups should be cut as soon as the mast years have produced sufficient seed yield or regeneration under the canopy or in areas set aside. Increasing the number of stands or demes (groups of trees) of different ages in the population enhances intra-population genetic variation as the portion of trees involved in regeneration increases. Regeneration can also be stimulated by site scarification and weed control. If these regeneration support measures are not successful, it is recommended that material originating from the population is planted: seeds lsior Fraxinus exc iorCommon ashFraxinus excelsiorCommon ashFraxinus excelsiorCommon ashFraxinus ex Guidelines for genetic conservation and use should be collected from at least 50 trees per population, preferably from central parts of the gene reserve. To prevent gene flow from outside the gene reserve, a buffer zone of 100-150 m should be created by gradually removing mature flowering ash trees within this zone.

To secure the sustainability of each population, careful tending is required. Effective treatment including adequate silvicultural measures, protection against disease or insect outbreaks, fire or other factors must be undertaken promptly. Thinning should be undertaken from below, removing suppressed and injured trees, thus simulating and stimulating the natural selection processes in the forest, and stand regeneration. Each gene conservation population must be constantly monitored, including the health status and regeneration success.

For populations that are marginal, isolated, endangered, growing under special ecological conditions or carrying rare features, in situ conservation should be complemented by ex situ measures. The most effective form is through progeny trials, which permits joint gene conservation and breeding. On a national scale, 1-3 progeny plantations for conservation/breeding (each of 2-4 ha in size) should be established in each provenance region with entries sampled from single trees randomly chosen from 10-20 stands within the region and from marginal populations if applicable. As soon as reproductive age is reached, open pollination of the best individuals selected within each family should ensure the next generation. About 50 optimally adapted individuals should be the founders of each new gene conservation/ breeding sub-population.

Fraxinus excelsio

Common ashFraxinus excelsiorCommon ashFraxinus excelsiorCommon ashFraxinus

Distribution range of common ash

Alfas Pliûra 1 and Myriam Heuertz 2 1

  Lithuanian Forest Research Institute, Girionys, Kaunas, Lithuania 2 Centre de Recherche Public -Gabriel Lippmann, Luxembourg