Journal of Applied Ecology 2003 40 , 947–969 © 2003 British Ecological Society Blackwell Publishing Ltd.Oxford, UKJPEJournal of Applied Ecology0021-8901British Ecological Society, 200312 2003406 Essay ReviewEcological effectiveness of agri-environment schemesD. Kleijn & W.J. Sutherland REVIEW How effective are European agri-environment schemes in conserving and promoting biodiversity? DAVID KLEIJN* and WILLIAM J. SUTHERLAND† Nature Conservation and Plant Ecology Group, Wageningen University, Bornsesteeg 69, 6708 PD Wageningen, The Netherlands; and † Centre for Ecology, Evolution and Conservation, School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK Summary 1. Increasing concern over the environmental impact of agriculture in Europe has led to the introduction of agri-environment schemes. These schemes compensate farmers financially for any loss of income associated with measures that aim to benefit the environment or biodiversity. There are currently agri-environment schemes in 26 out of 44 European countries. 2. Agri-environment schemes vary markedly between countries even within the Euro- pean Union. The main objectives include reducing nutrient and pesticide emissions, protecting biodiversity, restoring landscapes and preventing rural depopulation. In vir- tually all countries the uptake of schemes is highest in areas of extensive agriculture where biodiversity is still relatively high and lowest in intensively farmed areas where biodiversity is low. 3. Approximately $ 24·3 billion has been spent on agri-environment schemes in the Euro- pean Union (EU) since 1994, an unknown proportion of it on schemes with biodiversity conservation aims. We carried out a comprehensive search for studies that test the effec- tiveness of agri-environment schemes in published papers or reports. Only 62 evaluation studies were found originating from just five EU countries and Switzerland (5). Indeed 76% of the studies were from the Netherlands and the United Kingdom, where until now only c . 6% of the EU agri-environmental budget has been spent. Other studies were from Germany (6), Ireland (3) and Portugal (1). 4. In the majority of studies, the research design was inadequate to assess reliably the effectiveness of the schemes. Thirty-one percent did not contain a statistical analysis. Where an experimental approach was used, designs were usually weak and biased towards giving a favourable result. The commonest experimental design (37% of the studies) was a comparison of biodiversity in agri-environment schemes and control areas. However, there is a risk of bias if either farmers or scheme co-ordinators select the sites for agri-environment schemes. In such cases the sites are likely to have a higher biodiversity at the outset compared to the controls. This problem may be addressed by collecting baseline data (34% of studies), comparing trends (32%) or changes (26%) in biodiversity between areas with and without schemes or by pairing scheme and control sites that experience similar environmental conditions (16%). 5. Overall, 54% of the examined species (groups) demonstrated increases and 6% decreases in species richness or abundance compared with controls. Seventeen percent showed increases for some species and decreases for other species, while 23% showed no change at all in response to agri-environment schemes. The response varied between taxa. Of 19 studies examining the response of birds that included a statistical analysis, four showed significant increases in species richness or abundance, two showed decreases and nine showed both increases and decreases. Comparative figures for 20 arthropod studies yielded 11 studies that showed an increase in species richness or abundance, no study showed a decrease and three showed both increases and *Correspondence: David Kleijn. fax +31 317 484845. E-mail david.kleijn@wur.nl 948 D. Kleijn & W. J. Sutherland © 2003 British Ecological Society, Journal of Applied Ecology , 40 , 947–969 decreases. Fourteen plant studies yielded six studies that showed increases in species richness or abundance, two showed decreases and no study showed both increases and decreases. 6. Synthesis and applications . The lack of robust evaluation studies does not allow a general judgement of the effectiveness of European agri-environment schemes. We sug- gest that in the future, ecological evaluations must become an integral part of any scheme, including the collection of baseline data, the random placement of scheme and control sites in areas with similar initial conditions, and sufficient replication. Results of these studies should be collected and disseminated more widely, in order to identify the approaches and prescriptions that best deliver biodiversity enhancement and value for money from community support. Key-words : EEC Regulation 2078/ 92, farmland, policy evaluation, wildlife conservation. Journal of Applied Ecology (2003) 40 , 947–969 Introduction Post-war European agriculture can be considered a success in that it has resulted in increased yields and an enhanced capacity for self-sufficiency. For example, in the UK the yields per hectare of wheat, barley, potatoes and sugar beet have tripled since 1950, while over the same time milk yields have more than doubled (Pretty et al . 2000). However, it is widely accepted that in- creased agricultural productivity has associated costs in economic, consumer perception and environmental terms. More recently, there has been a global shift towards reducing subsidies. For example, in the UK, manufac- turing subsidies have been virtually eliminated, yet agriculture remains heavily subsidized at about 40% of the income. The free trade talks of the World Trade Organization have repeatedly identified agricultural sub- sidies as an area badly needing reform, especially the European Union (EU) Common Agricultural Policy (Yu, Sutherland & Clark 2002). The $ 16 900 million annual cost of the European Union Common Agricul- tural Policy largely comprises direct payments to farmers, price support, taxing imports from non-EU countries, subsidizing exports and paying for storage when no market is available. As a result, prices in the European Union exceed those on the international market. The external costs of agriculture were estimated by Pretty et al . (2001) to be about $ 180 per hectare of grassland and arable, with external benefits equivalent to $ 17 to $ 50 per hectare. It is widely accepted that the expansion of the European Union in 2004 to include Cyprus, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia will make the current agricultural support mechanisms financially unviable (Donald et al . 2002). Consumers are currently questioning the benefits of intensive agriculture. While the concerns may not nec- essarily always be rational (Beringer 2000), there is clear public mistrust and distaste for some aspects of modern agriculture. The intensification of agriculture has resulted in major environmental problems in recent decades, not- ably declines in bird populations together with their associated food resources (Donald, Green & Heath 2000; Benton et al . 2002; Robinson & Sutherland 2002) and this is likely to continue (Tilman et al . 2001). Future intensification, such as the use of genetically modified crops, is likely to have further detrimental consequences for biodiversity (Watkinson et al . 2000). There are also implications for wider environmental issues, such as flood risk and effects on water quality (Sutherland 2002). One response to concerns over biodiversity loss has been the introduction of agri-environment schemes, in which farmers are paid to modify their farming practice to provide environmental benefits. The EU agricultural policy first explicitly addressed the impact of agriculture on the environment in a Green Paper published in 1985 (CEC 1985). The reform of the EU agricultural policy in that year (EEC Regulation 797/ 85) included a novel set of measures for environmental protection and Article 19 allowed Member States to pay national aid in environmentally sensitive areas (ESAs). In 1992 EEC Regulation 2078/92 was intro- duced, requiring all EU member states to apply agri- environment measures according to environmental needs and potential. Between 50% and 75% of the costs of approved agri-environment schemes are co-funded by the EU, making this regulation a financially attract- ive form of environmental protection. Concurrently, extensive agri-environment programmes were developed in Norway and Switzerland (both non-EU Member States) and in Austria and Sweden before their entry into the EU in 1995. Besides their intended positive effects on biodiversity and the environment, agri-environment schemes decouple payments from agricultural output. Thus they continue to provide income transfers to farm- ers, but in a way that does not distort world markets (Potter & Goodwin 1998; Matthews 2002). More than a decade after the introduction of regu- lation 2078/92, little information is available on the 949 Ecological effectiveness of agri-environment schemes © 2003 British Ecological Society, Journal of Applied Ecology , 40 , 947–969 effects of agri-environment schemes on biodiversity conservation. The limited number of studies that have been published present contrasting results (e.g. Kleijn et al . 2001; Peach et al . 2001). Most EU countries are currently implementing their second 5-year agri- environment programme. National schemes have been initiated in three, and there are plans for pilot incentive schemes in another six Central and Eastern European countries (Petersen & Feehan 2003). There is an obvi- ous need for an overview that shows exactly what agri- environment schemes achieve in terms of biodiversity conservation. We attempt such a review here. First, we briefly describe the differences in design and implementation of agri-environment programmes between countries in Europe. Subsequently, we review the effectiveness of agri-environment schemes by surveying all available literature, with the aim of integ- rating the findings of various studies to produce recom- mendations for improvement. We have restricted ourselves to the effects of schemes on biodiversity. We only consider schemes implemented until 2000, as the new modified programmes are too recent for proper evaluation. We do not consider set-aside schemes, as these are not formally agri-environment schemes but a means of reducing production, and their ecological merits have been discussed elsewhere (Clarke 1992; Buckingham et al . 1999). Likewise, although organic farming is an agri-environment scheme and support is co-funded by the EU under Regulation 2078/92, we do not consider the effects of organic farming as this has been discussed extensively elsewhere and the objectives are not necessarily biodiversity conservation (Weibull, Bengtsson & Nohlgren 2000; Mäder et al . 2002). Design of agri-environment programmes across Europe For clarity, in this review we distinguish between agri- environment programmes, schemes and measures. We consider an agri-environment programme to be the collection of schemes implemented in a country. Indi- vidual schemes have different objectives (e.g. grassland extensification or conservation of endangered livestock breeds) and regularly consist of a set of measures. For example, in the case of a grassland extensification scheme, measures (also called prescriptions) may con- sist of a reduction in stocking densities or a cessation of fertilizer inputs. Agri-environment programmes vary markedly be- tween countries in Europe (Table 1). The objectives of these programmes usually reflect a combination of the main environmental, ecological and socio-economic problems associated with agriculture, as well as the political situation in each country. In Switzerland, the Netherlands and the United Kingdom, schemes avail- able to farmers concentrate on wildlife and habitat con- servation. In Denmark and Germany most schemes offered to farmers aim to reduce agrochemical emis- sions, while in France the programme is geared towards the prevention of land abandonment in agriculturally marginal areas. In Ireland and Austria, the objectives of programmes are balanced between environmental protection, biodiversity conservation and landscape maintenance (Table 1). Schemes can be implemented either horizontally throughout the country or zonally (also known as ‘tar- geted’ or ‘vertically’) in certain areas that have been identified as being particularly vulnerable or a local biodiversity hotspot (e.g. environmentally sensitive areas (ESAs)). The designation of areas where zonal measures can be implemented is usually carried out by governmental organizations. Most countries have a combination of both approaches because a limited set of zonal schemes exist that aim to conserve vulnerable ecosystems. Switzerland and Finland are the only countries that have entirely horizontal programmes, although most schemes in the German, Irish and Swedish programmes are applied horizontally. By contrast, most schemes in the United Kingdom and Spain are implemented in a zonal manner. A more extensive discussion of the history and lay-out of the agri-environment programmes in a range of European countries is given in Buller, Wilson & Höll (2000). Patterns of implementation of agri-environment programmes Differences in uptake rate of individual schemes largely determine whether and where the overall objectives of agri-environment programmes can be met. In most countries uptake is very unequally divided over the available schemes, with a single scheme usually com- prising more than 40% of the total area covered by agri- environment schemes (Table 1). Furthermore, schemes are often unequally distributed geographically across countries, with high uptake rates in areas with extensive agriculture and low uptake rates in areas where agri- culture is more intensive (Emerson & Gillmor 1999; Buller & Brives 2000; Grafen & Schramek 2000). The mechanism resulting in this pattern is illustrated in Fig. 1(a), which shows that for extensive farmers par- ticipation in an agri-environment programme is asso- ciated with comparatively low costs of adaptation. Few changes are required to meet the requirements of the schemes (Osterburg 2001). Thus, when uniform pay- ments per hectare (calculated on an average base) are offered for voluntary measures, most uptake will occur in less favoured areas. The same mechanism probably explains why in most countries (especially France and Austria) the low impact/low compensation schemes are those with the highest uptake. The effects of agri-environment schemes on biodiversity EU members are obliged to evaluate their agri- environment programme with respect to their socio- economic, agricultural and environmental aspects (Article 950 D. Kleijn & W. J. Sutherland © 2003 British Ecological Society, Journal of Applied Ecology , 40 , 947–969 Table 1. Characteristics of agri-environment programmes in European countries until the year 2000. Pilot agri-environment schemes currently applied in CEE countries are not included. UAA, Utilized Agricultural Area; AEP, agri-environment programme; AES, agri-environment scheme; ECA, ecological compensation area Austria. (UAA ’95 3 425 100 ha; area with AES ’97 2 500 000 ha; AEP since 1995, previous programme outside the EU-context since 1972). The Austrian programme (ÖPUL) consists of 25 schemes. Eight horizontal schemes address extensification and reduction of the negative impact of agriculture on the environment, the other zonal schemes address specific farming practices, biodiversity conservation and the creation or conservation of landscape elements. ÖPUL aims to promote farming with reduced environmental impact, maintain farming in agriculturally marginal areas (Alps) and conserve biodiversity and landscape. However, in 1996 83% of the budget was spent on the horizontal schemes and only 17% on schemes aimed at biodiversity and landscape conservation. Schemes with the highest uptake : crop rotation stabilization (18% of AEP budget) and the basic subsidy (17%). Source: Groier & Loibl (2000). Belgium . (UAA ’95 1 354 400 ha; area with AES ’97 17 000 ha; AEP since 1994). In Flanders no AEP existed before 2000 (Reheul & van Huylenbroeck 2000). The Walloon programme consists of five horizontal schemes and six zonal schemes. The programme addresses environmental and biodiversity aspects more or less equally but in 1997 only 25% of the AEP area was under some scheme addressing biodiversity or landscape conservation issues. Highest uptake : planting a cover-crop between two crops (41%) and restricting stocking densities to between 0·6 and 1·4 lifestock units (26% of AEP area). Source: Walot (2002). Denmark . (UAA ’95 2 726 600 ha; area with AES ’97 94 000 ha; AEP since 1992, previous schemes under regulation 797/85 since 1990). The majority of the schemes of the Danish AEP are applied zonally (ESA approach). Schemes aimed at the reduction of nitrogen use, promotion of rygrass as ground cover and organic farming can be implemented throughout the country. The main objective of the Danish AEP is to achieve a reduction in nitrogen inputs. Landscape and nature protection has been of minor importance so far. Highest uptake : maintenance of extensive grasland (52% of AEP area) and organic farming (37%). Source: Andersen, Henningsen & Primdahl (2000). Finland . (UAA ’95 2 191 700 ha; area with AES ’97 2 000 000 ha; AEP since 1995). Finland has a strictly horizontal ‘General Protection Scheme’ (GPS) with six compulsory basic measures and five additional measures of which one has to be selected. Furthermore, a ‘Special Protection Scheme’ (SPS, 12 measures) exists that is optional but participation is available only in combination with the GPS. The emphasis of the Finnish programme is on environmental aspects: one of six compulsory measures and one of five additional measures of the GPS address biodiversity and landscape maintenance. Three of the 12 measures of the SPS address promotion of biodiversity and landscape. Source: M. Kaljonen (unpublished paper). France . (UAA ’95 28 267 200 ha; area with AES ’97 5 725 000 ha; AEP since 1992, previous schemes under regulation 797/85 since 1989). In France, national and regional schemes exist alongside ‘local operations’. As regional schemes are the same in each region, both the national and the regional schemes can be considered horizontal whereas the local operations are zonal. Main goal of the AEP is to maintain agricultural activities in areas with a high risk of agricultural land abandonment and rural depopulation. Highest uptak e: the national scheme – maintenance of extensive animal husbandry (70% of the total AEP budget) and local operations ( c . 15% of AEP budget). By 1997 some 67% of the local operations addressed wildlife and ecosystem protection. Source: Buller & Brives (2000). Germany . (UAA ’95 17 156 900 ha; area with AES ’97 6 353 000 ha; AEP since 1992, previous schemes under regulation 797/85 since 1985). The German AEP is difficult to summarize as each federal state (‘Land’) has its own AEP. Almost all schemes are horizontal within each federal state with the exception of schemes aimed at the protection of environment, natural resources, countryside and landscape, which are zonal in some of the states. German agri-environment schemes can be divided in two main types. First, schemes aimed at changing farming practices and second, schemes aimed at the preservation of specific environmentally vulnerable areas, biotopes or species. The latter schemes contribute only 9% of the total AEP area (Osterburg 2001), however, in some federal states these schemes operate outside the framework of regulation 2078/92 and are therefore not co-funded by the EU. c . 70% of the German AEP budget between 1993 and 1996 was spent by the agriculturally extensive German states Bayern, Baden- Würtemberg and Sachsen. Highest uptak e: environmentally orientated basic payment – only in Bayern and Sachsen (57% of total German AEP budget) and grassland schemes – extensification, conversion to arable land, preservation of specific biotopes (23%). Source: Grafen & Schramek (2000). Greece . (UAA ’95 3 464 800 ha; area with AES ’00 c . 49 500 ha; AEP since 1995, previous schemes under regulation 797/85 since 1986). So far, five of a projected 13 schemes have been implemented. The schemes address organic plant production, organic livestock production, 20-year set aside, reduction of nitrogen pollution and conservation of endangered breeds. Highest uptak e: reduction of nitrogen pollution (29·500 ha). Source: Louloudis, Beopoulos & Vlahos (2000), Louloudis & Dimopoulos (2001). Ireland . (UAA ’95 4 324 500 ha; area with AES ’99 1 575 000 ha; AEP since 1994). The Irish Rural Environmental Protection Scheme (REPS) consists of one scheme only with 11 compulsory measures and a further six ‘Supplementary Measures’. The basic scheme is very comprehensive and addresses biodiversity and environmental protection, training courses and keeping of farm and environmental records. The REPS aims to conserve wildlife habitats and endangered species of flora and fauna as well as to address environmental problems. Five compulsory measures are particularly relevant to biodiversity conservation. All Supplementary Measures are primarily aimed at conservation aspects and only apply in designated areas. Source: Emerson & Gillmor (1999). Italy . (UAA ’95 14 685 500 ha; area with AES ’97 1 608 000 ha; AEP since 1994/1995). Italy is divided into 21 regions, each having their own agri-environmental programme. Within regions most schemes are implemented horizontally. The AEP is primarily used as an instrument to reduce the negative impact of agriculture on the environment. Biodiversity conservation is only addressed indirectly through the maintenance of the countryside and the landscape scheme. However, 94% of this scheme is implemented in the provinces of Bolzano, Trento and Valle d’Aosta, and is therefore virtually restricted to the alpine region. Highest uptake: reduction of fertilizer and pesticides inputs (37% of AEP area) and maintenance of countryside and landscape (32%). Source: INEA (1999). 951 Ecological effectiveness of agri-environment schemes © 2003 British Ecological Society, Journal of Applied Ecology , 40 , 947–969 Luxembourg . (UAA ’95 126 900 ha; area with AES ’97 97 000 ha; AEP since 1996). Only one scheme, available to all farmers in Luxembourg, had been implemented in 1997. This scheme addressed maintenance of the countryside and landscape. Source: Anonymous (1998). Norway . (UAA 980 000 ha; area with AES unknown). Norway has two major agri-environment schemes. The Acreage and Cultural Landscape Scheme is mainly aimed at maintaining agricultural practices in marginal areas and has general prescriptions that are easy to adapt to. The Special Measures for the Cultural Landscape Scheme consists of much more detailed prescriptions, many having objectives aimed at nature conservation. Highest uptak e: unknown. Source: Rønningen (2001). Portugal . (UAA ’95 3 924 600 ha; area with AES ’97 606 000 ha; AEP since 1994). Only schemes addressing the reduction of agricultural pollution and training courses and demonstration projects are applied horizontally, all other schemes are zonal and most of them address specific farming systems. Emphasis of the Portugese AEP is on the maintenance of extensive farming systems. The schemes with the expected highest uptake rates are those aimed at the maintenance of extensive grazing systems and Holm Oak landscapes (‘montados’) . Highest uptak e: not available yet. Source: Eden & Vieira (2000). Spain . (UAA ’95 25 230 300 ha; area with AES ’97 532 000 ha; AEP since 1993). The Spanish AEP is implemented by the individual regions but a set of mandatory horizontal and zonal schemes is prescribed by the national government. The implementation of the Spanish scheme has met with considerable delay and data on uptake are only preliminary. Estimated budget allocation suggests that the emphasis of the Spanish AEP lies on landscape protection (48% of AEP budget) and extensification (30%). Highest uptak e: preliminary data indicate that landscape conservation and fire prevention in extensive grasslands are the two schemes with the highest uptake rates followed by schemes aimed at wildlife protection in extensive croplands. Source: Peco et al . (2000). Sweden . (UAA ’95 3 059 700 ha; area with AES ’97 2 449 990 ha; AEP since 1995, previous schemes outside the EU-context since 1986). The Swedish AEP consists of four clusters of schemes each having a different objective. The ‘environmentally sensitive area’ cluster is zonal, the others are basically horizontal. The AEP objectives are to maintain a naturally and culturally valuable and varied landscape, to conserve biodiversity and to minimize nutrient leaching and pesticide use. Uptake figures indicate that schemes aimed at the maintenance of open landscapes and conservation of cultural-historical remains are very popular, whereas uptake of schemes aimed at biodiversity conservation remain far below the targeted areas. Highest uptak e: maintenance of open landscape in forest and northern regions (30% of AEP area) and perennial ley farming (29%). Source: Carlsen & Hasund (2000). Switzerland . (UAA ’99 985 000 ha; area with ECA ’99 82 700 ha; ECA since 1993). The Swiss AEP differs considerably from that of EU-member countries. Farmers throughout Switzerland may manage at least 7% of their UAA as so-called Ecological Compensation Areas (ECAs) in order to obtain a basic direct payment. The 7% ECA may consist of a variety of biotopes such as extensive grasslands, traditional orchards, hedges, field margin strips, conservation headlands, ditches, stone walls or unpaved roads. Farmers can receive additional management subsidies for some of these biotopes, such as extensive grasslands. Some types of biotopes, such as again extensive grasslands, that meet a certain quality level and/or are located in ecological corridors between important habitats qualify for additional subsidies. The overall aim of ECAs is halting the agriculturally induced loss of biodiversity by conserving valuable biotopes, restoring degraded biotopes and creating new biotopes. Highest uptak e: low- intensity meadows (49% of ECA area) and extensively used meadows (41%). Source: Günter et al . (2002). The Netherlands . (UAA ’95 1 998 900 ha; area with AES ’99 c . 70 000 ha; AEP since 1992, previous schemes partly under regulation 797/85 and partly outside the EU-context since 1981). The Dutch AEP consists of seven schemes. One scheme (management agreements) specifically addresses the maintenance and conservation of biodiversity and landscape and is applied zonally. All other schemes address a variety of topics including demonstration projects, training courses and public access to farmland. In budgetary terms the zonal scheme is by far the most important. Highest uptake : management agreements (90% of AEP area). Source: Anonymous (2000). The United Kingdom . (UAA ’95 16 446 600 ha; area with AES ’97 1 322 000 ha; AEP since 1992, previous schemes under regulation 797/85 since 1987). The AEP varies somewhat between England, Wales, Scotland and Northern Ireland but the basic outline is the same. For the whole of the UK nine different schemes exist of which only one, the ‘Organic Aid Scheme’ is truly horizontal. Others can either be applied in certain regions or address certain biotopes. There is a strong emphasis in the UK AEP on wildlife conservation. The concept of Environmentally Sensitive Areas (ESA) was originally developed in the UK and first implemented here under regulation 797/85 and still forms the backbone of the UK AEP. Wildlife conservation in the wider countryside is addressed by the Countryside Stewardship Scheme. Environmental issues play a minor role (Nitrate Sensitive Areas scheme and Organic Aid Scheme). Highest uptake : ESA scheme (58% of AEP budget and 74% of area) and Countryside Stewardship Scheme (21% of budget and 7% of area). Source: Hart & Wilson (2000). Table 1. Continued 16, EC Regulation 746/96). Currently, most evaluation studies simply examine uptake patterns of different schemes within programmes. However, implementation of schemes does not guarantee that the stated object- ives of the scheme will actually be met. Furthermore, the biodiversity and environmental objectives are rarely defined clearly at the outset, which hampers proper evaluation in a number of countries (Schramek 2001). Table 2 summarizes all those studies that we have been able to locate that evaluate the effects of agri- environment schemes on the abundance or species rich- ness of organisms. Initially, we performed an extensive literature review. However, as most evaluation studies are published outside the mainstream scientific jour- nals, we also searched the internet and approached some 40 key people outside the Netherlands and the United Kingdom to ascertain whether they knew of any evaluation studies in their country or of any person who might have more information. Many studies claimed to evaluate the effects of schemes but simply 952 D. Kleijn & W. J. Sutherland © 2003 British Ecological Society, Journal of Applied Ecology , 40 , 947–969 described the status or trends of species of interest in the scheme site without any reference or control data. These studies cannot be used to infer effects of the changes in management due to the agri-environment schemes, hence we did not consider them further in this review. Although we may have missed some studies, we are confident that we have conducted a thorough search for studies throughout Europe. We located 62 studies from just six countries, of which 76% were from just two countries (18 from the Netherlands and 29 from the United Kingdom). Only 27% (17) of the stud- ies were published in international peer-reviewed jour- nals. Excluding the United Kingdom and Ireland, 83% of the studies were published in the national language and remain therefore largely inaccessible to people out- side that country (Table 2, Table 3).         The approaches to evaluation varied enormously, even within individual countries, making it very difficult to ascribe a specific study design (Table 2). For example, the most common approach (37% of the studies) com- pared biodiversity in the agri-environment scheme and control areas at one point in time. However, some stud- ies compared entire areas with a mosaic of schemes, nature reserves and conventional management with areas that were managed conventionally throughout and usually were located outside ESAs. Other studies compared the pooled species diversity of all fields with agri-environment schemes with the pooled species diversity of all conventionally managed fields in a sin- gle area that consisted of a mosaic of scheme and con- ventional fields. The same difficulties apply to the two other common study design, examining changes in bio- diversity (26% of the studies) or trends in time in areas with and without schemes (32%). Only 34% of the stud- ies included baseline data, and 16% used a paired study approach to reduce environmental noise (Table 3). The number of replicates varied from 1 to 398. The number of controls was often similar to the number of replicates but in some cases far larger or smaller (161 controls for 26 experimental replicates and, of greater concern, 2 controls for 82 experimental replicates). Two Swiss studies compared the spatial distribution of birds over the landscape and analysed whether sites with schemes were used by birds more than would be expected based on a random distribution. These stud- ies did not contain formal control areas. The data from 31% of the studies were not analysed statistically. Some reports divided the analysis into a number of groups, such as common vs. Red List plant species. To avoid replication and information overload we selected the measure (usually species richness) that seemed to best represent the results. We checked that this was not dis- torting the conclusions. Twenty studies (32%) assessed the effects of schemes on plants, 20 (32%) on various insect groups and spiders, one (2%) on mammals (brown hare Lepus euro- paeus Pallas) while 29 (47%) studies investigated the response of birds.         Our results show that plant diversity may be difficult to enhance with agri-environment schemes (Table 2). Eleven of the 20 studies addressing botanical diversity found positive effects of schemes whereas two studies reported negative effects. Considering the subsample of 14 studies that subjected the data to some form of statistical analysis, six studies demonstrated positive and two studies demonstrated negative effects of schemes, the remaining seven studies finding no effect at all. The poor performance of the evaluated agri- environment schemes with botanical objectives is in accordance with results of experimental studies. These generally show that it is extremely difficult to enhance the botanical diversity of intensively farmed agricultural Fig. 1. Conceptual models describing (a) the relationship between farming intensity and the impact of schemes on a farmer’s activities (solid line) as well as the uptake of those schemes (dashed line), and illustrating (b) the potential effects of schemes addressing ‘improvement effects’ and ‘protection effects’ (sensu Primdahl et al. 2003). An equal shift in land-use intensity may result in a more pronounced effect on biodiversity (shaded area) in extensive areas compared with intensive areas. 953 Ecological effectiveness of agri-environment schemes © 2003 British Ecological Society, Journal of Applied Ecology , 40 , 947–969 Table 2. Summary of characteristics of studies that evaluate the effectiveness of agri-environment schemes. Number of replicates and controls in numbers unless other units are given. For abbreviations see Table 1. Studies that just report status or changes within schemes were excluded Country Scheme Investigated species (group) Design Number of replicates Number of controls Statistical analysis Base-line data Duration study Results Notes Reference CH ECA – wildflower strips Skylark Relative biotope use within skylark territories 24 territories –Yes No 1995 Skylarks foraged more frequently and longer in wildflower strips than in any other biotope Weibel (1998) CH ECA – extensive grasslands Carabid beetles Comparison ECA and control sites 16, 7† 7 No No 1997 Higher number of species and red list species on extensive and low-intensity grasslands compared to control Pfiffner et al . (2000)* CH ECA Grass-hoppers Species richness and abundance on target sites and wider countryside before and after schemes 62 398 Yes Yes 1990 & 2000 Proportion of ECA area relative to total area occupied by grasshoppers increased significantly for seven species from 1990 to 2000 ECA sites were perennial biotopes only whereas controls included arable fields Hunziker (2001) CH ECA – extensive grasslands Grass-hoppers Species richness and abundance on target and control sites before and after schemes 152 152 Yes Yes 1990 & 2000 Species richness and abundance of individual species increased more on fields with ECA Peter & Walter (2001)* CH ECA Birds Spatial distribution of territories relative to that of ECA sites 23 – Yes No 1998 & 1999 Five species (mostly hedgerow species) more abundant, one species less abundant on/near ECAs than expected Spatial autocorrelation between ECA and vertical structures. Explains part of the observed effects Hofer et al . (2002)*, Spiess, Marfurt & Birrer (2002)* D Conservation headlands for arable weeds Hoverflies and carabid beetles Comparison AES and control sites 22No No 1988 Species richness and abundance of hoverflies and carabid beetles higher on AES sites Raskin (1994)* ( Cont’d ) 954 D. Kleijn & W. J. Sutherland © 2003 British Ecological Society, Journal of Applied Ecology, 40, 947–969 D Conservation of wet meadows Black-tailed godwit, curlew, snipe Population trends inside/outside AES area 22No No 1989–98 Number of pairs inside stable and outside declining or inside declining less rapidly than outside AES area Scheme areas include fields of nature conservation organization Weiss et al. (1999)* D Conservation of wet meadows Waders Population trends inside/outside AES area 2292 ha 437 ha No No 1988–98 Number of pairs inside stable and outside declining or inside declining less rapidly than outside AES area Scheme areas include fields of nature conservation organization Ikemeyer & Krüger (1999)* D ‘Mittelgebirgs- programm’ – grassland extensification Plants Changes in species richness on fields with and without AES 29 53 No Yes 1986 & 1997 Plant species richness increases on fields with AES and remains stable on control fields Weis (2001)* D ‘Mittelgebirgs- programm’ – Resumed grazing on abandoned pastures Plants Trends in species richness on grazed AES fields and exclosures that serve as controls 86No Yes 1987–90, 1994, 1996 & 1999 Plant species richness increases slightly in grazed plots on AES fields and decreases sharply in exclosures Weis (2001)* DGrazing extensification Plants, various insect groups Species richness and abundance in a randomized block design 66Ye sNo1996 Plant diversity not different, insect richness and abundance significantly higher on scheme sites relative to control sites Kruess & Tscharntke (2002a,b) EI REPS scheme Plants and carabid beetles in grasslands Species richness in field boundaries on farms with and without REPS 15 15 Yes No 1999 Plant species richness lower; carabid beetle richness similar to control farms Feehan, Gillmor & Culleton (2002) EI REPS scheme Plants and carabid beetles in tillage land Species richness in field boundaries on farms with and without REPS 15 15 Yes No 2000 Species richness of plants and carabid beetles similar on REPS and control farms Feehan et al. (2002) Country Scheme Investigated species (group) Design Number of replicates Number of controls Statistical analysis Base-line data Duration study Results Notes Reference Table 2. Continued 955 Ecological effectiveness of agri-environment schemes © 2003 British Ecological Society, Journal of Applied Ecology, 40, 947–969 EI REPS scheme Farmland birds Species richness on farms with and without REPS 55Ye sNo2000 Bird species richness similar on REPS and control farms Flynn et al. (2002) NL Botanical management agreements Plants Comparison of changes on fields with and without AES 35 9 No No 1984/85 & 1990 Changes in species richness/cover similar on AES fields and controls Most of the control fields located outside the ESA Altenburg & Wymenga (1991)* NL Meadow bird agreements Meadow birds Comparison of changes on fields with and without AES 23 ha 81 ha No Yes 1988 & 1991 Trends in settlement densities similar on fields with and without AES Terlouw (1992)* NL Meadow bird agreements Meadow birds Comparison of trends (1) in ESAs and control areas and (2) inside ESAs on fields with and without schemes 1 : 11 2 : 90 1 :7 2 : 276 Ye sPartially 1986− 90 1. Trends of two species more positive and one species more negative in ESAs relative to outside ESAs 2. Trends of lapwing more positive on AES fields than control fields 1. ESAs include reserves 2. Prior to the scheme higher densities of three and lower densities of two species were present on AES fields relative to control fields Van den Brink & Fijn (1992)* NL Botanical management agreements Plants Comparison of trends (1) in ESAs and control areas and (2) inside ESAs on fields with and without schemes 45–169† 29–35† Yes Partially 1986−90 1. In ESAs more positive vegetation development than outside ESAs in both ditch banks and grasslands 2. Trends more positive on AES fields than control fields in both ditch banks and grasslands 1. ESAs include reserves 2. Prior to scheme ditch banks contain less and grasslands more species on AES fields relative to controls Van den Brink & Fijn (1992)* Country Scheme Investigated species (group) Design Number of replicates Number of controls Statistical analysis Base-line data Duration study Results Notes Reference Table 2. Continued (Cont’d) 956 D. Kleijn & W. J. Sutherland © 2003 British Ecological Society, Journal of Applied Ecology, 40, 947–969 NL Meadow bird agreements Meadow birds Comparison of population trends on fields with and without AES 119 ha 144 ha No No 1987−91 Population trends more positive on AES fields for three species Brandsma (1993)* NL Meadow bird agreements Meadow birds Comparison of population trends on fields with and without AES 122 ha 702 ha No No 1983, 1986, 1989, 1992 & 1995 Population trends more positive on AES fields for six species Altenburg, Rebergen & Wymenga (1993)*, Uilhoorn (1996)* NL Botanical management agreements Vegetation Comparison of shifts in vegetation classes on fields with and without AES 255 ha 117 ha No No 1987 & 1993 Shift towards qualitatively better vegetation classes between 1987 and 1993 more pronounced on fields with AES Vegetation broadly classified, significance of results difficult to interpret Wymenga, Jalving & Jansen (1994)* NL Meadow bird agreements Meadow birds Comparison of population trends on fields with and without AES 388 ha 420 ha No No 1985, 1987, 1990 & 1993 Population trends less negative on AES fields for two species Most control fields outside ESA in area with woodlots Altenburg & Griffioen (1994)* NL Botanical management agreements Vegetation Comparison of changes in ‘Nature Value Index’s’ in edges of fields with and without AES 26 161 Yes Yes 1990 & 1994 Nature Value Index decreases significantly in edges of fields without but stays stable in edges of fields with AES Dijkstra (1994)* NL Botanical management agreements Vegetation Comparison of shifts in vegetation classes on fields with and without AES 86 ha 500 ha No No 1988 & 1994 Shift towards qualitatively better vegetation classes between 1988 and 1994 more pronounced on fields with AES Vegetation broadly classified, significance of results difficult to interpret Ter Stege, Jalving & Wymenga (1995)* NL Meadow bird agreements Meadow birds Comparison of population trends on fields with and without AES 115 ha 49 ha Yes No 1987, 1990 & 1993 No significant differences between fields with and without AES Van Buel & Vergeer (1995)* Country Scheme Investigated species (group) Design Number of replicates Number of controls Statistical analysis Base-line data Duration study Results Notes Reference Table 2. Continued [...]... the international scientic community, preferably through publication in international peer-reviewed journals, or by making an institution responsible for collating and distributing this type of research Only then will we be able to (i) nd out why some schemes are effective and others not, (ii) determine how existing schemes can be made more effective, and (iii) decide what schemes may be abandoned and. .. studies are weak The main approach was to compare areas of land under existing agri-environment schemes with control areas not covered by schemes If sites qualifying for agrienvironment schemes are located preferentially in the most diverse areas, comparisons between these and control sites will be biased towards giving favourable results Bias is unavoidable if study sites in designated areas (for instance... Five of ve target passerines increased Two of six breeding waders and waterfowl increased Signicant increases in species suited to grazing in AES stands contradicts target but increase in maritime species is as required Signicant increase in species richness in higher tier sites but not in control or lower tier Signicant increase in species richness in higher tier sites but not in control or lower tier... 947969 We are unable to say how effective agri-environment schemes are in protecting and promoting biodiversity on farmland A limited number of well-designed and thoroughly analysed studies demonstrate convincing positive effects measured in terms of increased species diversity or abundance, while other studies show no effects, negative effects, or positive effects on some species and negative effects... studies, thereby making an integrated analysis impossible (Wymenga, Jalving & Ter Stege 1996) Currently, agrienvironment incentive schemes are being initiated in the Central and Eastern European (CEE) countries that will join the EU in 2004, but, as far as we know, no evaluation studies are integrated into these programmes The implementation of nation-wide schemes, without learning from the mistakes... alternatives are (i) to collect baseline data, (ii) to examine trends in time, and (iii) to try to reduce systematic differences in initial conditions between scheme and control sites as far as possible Great care should be taken to pair scheme areas with nearby control areas that are similar in most respects (e.g soil type, groundwater table and landscape structure) so that these are eliminated as confounding... abandonment (Fig 1b; protection effects) Changes in land-use intensity will have a greater impact on biodiversity in extensively farmed land than on intensively used farmland (Fig 1b, see also Potter & Goodwin 1998) Agri-environment schemes that aim to protect biodiversity in extensively farmed areas may therefore be more effective than those aiming to improve biodiversity in intensively farmed areas... 58% 39% *Excluding 32 studies from UK and Ireland Including four studies with just two replicates Including three studies with just two replicates ĐBias resulting from scheme sites likely to be placed in better habitat reduced by use of baseline data, comparing trends/ changes in time or pairing of scheme and control sites *Published in the national language Design Scheme Country Wintering skylarks Comparison... AES elds Trends in species richness/ cover of (hay meadow) plant species more positive on elds with AES Results Within ESAs two elds within a pair in environmentally similar areas Within ESAs two elds within a pair in environmentally similar areas Within ESAs two elds within a pair in environmentally similar areas Analysis makes no distinction between conservation headlands and eld margin strips Notes... Sensitive Areas selected on the basis of their conservation interest) are compared with control areas outside designated areas Furthermore, farmers that volunteer to enter agrienvironment schemes may already farm in a more environmentally sensitive manner In the Netherlands this is compounded when farmers locate schemes on the more inaccessible or marginal elds within a farm (Kleijn et al., in press), and in . W.J. Sutherland REVIEW How effective are European agri-environment schemes in conserving and promoting biodiversity? DAVID KLEIJN* and WILLIAM J. SUTHERLAND† Nature Conservation and Plant. out why some schemes are effective and others not, (ii) determine how existing schemes can be made more effective, and (iii) decide what schemes may be abandoned and how new schemes should be formulated. Acknowledgements We. are weak. The main approach was to compare areas of land under existing agri-environment schemes with control areas not covered by schemes. If sites qualifying for agri- environment schemes are