How effective are European agri-environment schemes in conserving and promoting biodiversity?
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Journal of Applied REVIEW
D.
E
Ecological
ssay Review
Blackwell
Oxford,
Journal
JPE
British
0021-8901
612
40 Kleijn
2003 effectiveness
W.J. Sutherland
Ecological
of
UK&Publishing
Applied of 2003
Society,
Ecology
Ltd. agri-environment schemes
Ecology 2003
40, 947 – 969 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
© 2003 British
Ecological Society *Correspondence: David Kleijn. fax +31 317 484845. E-mail david.kleijn@wur.nl948 decreases. Fourteen plant studies yielded six studies that showed increases in species
D. Kleijn & richness or abundance, two showed decreases and no study showed both increases and
W. J. Sutherland 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
The intensification of agriculture has resulted in
Introduction
major environmental problems in recent decades, not-
Post-war European agriculture can be considered a ably declines in bird populations together with their
success in that it has resulted in increased yields and an associated food resources (Donald, Green & Heath
enhanced capacity for self-sufficiency. For example, in 2000; Benton et al. 2002; Robinson & Sutherland 2002)
the UK the yields per hectare of wheat, barley, potatoes and this is likely to continue (Tilman et al. 2001).
and sugar beet have tripled since 1950, while over the Future intensification, such as the use of genetically
same time milk yields have more than doubled (Pretty modified crops, is likely to have further detrimental
et al. 2000). However, it is widely accepted that in- consequences for biodiversity (Watkinson et al. 2000).
creased agricultural productivity has associated costs There are also implications for wider environmental
in economic, consumer perception and environmental issues, such as flood risk and effects on water quality
terms. (Sutherland 2002).
More recently, there has been a global shift towards One response to concerns over biodiversity loss has
reducing subsidies. For example, in the UK, manufac- been the introduction of agri-environment schemes,
turing subsidies have been virtually eliminated, yet in which farmers are paid to modify their farming
agriculture remains heavily subsidized at about 40% practice to provide environmental benefits. The EU
of the income. The free trade talks of the World Trade agricultural policy first explicitly addressed the impact
Organization have repeatedly identified agricultural sub- of agriculture on the environment in a Green Paper
sidies as an area badly needing reform, especially the published in 1985 (CEC 1985). The reform of the EU
European Union (EU) Common Agricultural Policy agricultural policy in that year (EEC Regulation 797/
(Yu, Sutherland & Clark 2002). The $16 900 million 85) included a novel set of measures for environmental
annual cost of the European Union Common Agricul- protection and Article 19 allowed Member States to
tural Policy largely comprises direct payments to farmers, pay national aid in environmentally sensitive areas
price support, taxing imports from non-EU countries, (ESAs). In 1992 EEC Regulation 2078/92 was intro-
subsidizing exports and paying for storage when no duced, requiring all EU member states to apply agri-
market is available. As a result, prices in the European environment measures according to environmental
Union exceed those on the international market. The needs and potential. Between 50% and 75% of the costs
external costs of agriculture were estimated by Pretty of approved agri-environment schemes are co-funded
et al. (2001) to be about $180 per hectare of grassland by the EU, making this regulation a financially attract-
and arable, with external benefits equivalent to $17 to ive form of environmental protection. Concurrently,
$50 per hectare. It is widely accepted that the expansion extensive agri-environment programmes were developed
of the European Union in 2004 to include Cyprus, in Norway and Switzerland (both non-EU Member
Czech Republic, Estonia, Hungary, Latvia, Lithuania, States) and in Austria and Sweden before their entry into
Malta, Poland, Slovakia and Slovenia will make the the EU in 1995. Besides their intended positive effects
current agricultural support mechanisms financially on biodiversity and the environment, agri-environment
unviable (Donald et al. 2002). schemes decouple payments from agricultural output.
Consumers are currently questioning the benefits of Thus they continue to provide income transfers to farm-
© 2003 British
intensive agriculture. While the concerns may not nec- ers, but in a way that does not distort world markets
Ecological Society,
Journal of Applied essarily always be rational (Beringer 2000), there is (Potter & Goodwin 1998; Matthews 2002).
Ecology, 40, clear public mistrust and distaste for some aspects of More than a decade after the introduction of regu-
947–969 modern agriculture. lation 2078/92, little information is available on the949 effects of agri-environment schemes on biodiversity the prevention of land abandonment in agriculturally
Ecological conservation. The limited number of studies that have marginal areas. In Ireland and Austria, the objectives
effectiveness of been published present contrasting results (e.g. Kleijn of programmes are balanced between environmental
agri-environment et al. 2001; Peach et al. 2001). Most EU countries protection, biodiversity conservation and landscape
schemes are currently implementing their second 5-year agri- maintenance (Table 1).
environment programme. National schemes have been Schemes can be implemented either horizontally
initiated in three, and there are plans for pilot incentive throughout the country or zonally (also known as ‘tar-
schemes in another six Central and Eastern European geted’ or ‘vertically’) in certain areas that have been
countries (Petersen & Feehan 2003). There is an obvi- identified as being particularly vulnerable or a local
ous need for an overview that shows exactly what agri- biodiversity hotspot (e.g. environmentally sensitive
environment schemes achieve in terms of biodiversity areas (ESAs)). The designation of areas where zonal
conservation. We attempt such a review here. measures can be implemented is usually carried out by
First, we briefly describe the differences in design governmental organizations. Most countries have a
and implementation of agri-environment programmes combination of both approaches because a limited set
between countries in Europe. Subsequently, we review of zonal schemes exist that aim to conserve vulnerable
the effectiveness of agri-environment schemes by ecosystems. Switzerland and Finland are the only
surveying all available literature, with the aim of integ- countries that have entirely horizontal programmes,
rating the findings of various studies to produce recom- although most schemes in the German, Irish and
mendations for improvement. We have restricted Swedish programmes are applied horizontally. By
ourselves to the effects of schemes on biodiversity. We contrast, most schemes in the United Kingdom and
only consider schemes implemented until 2000, as the Spain are implemented in a zonal manner. A more
new modified programmes are too recent for proper extensive discussion of the history and lay-out of the
evaluation. We do not consider set-aside schemes, as agri-environment programmes in a range of European
these are not formally agri-environment schemes but a countries is given in Buller, Wilson & Höll (2000).
means of reducing production, and their ecological
merits have been discussed elsewhere (Clarke 1992;
Patterns of implementation of agri-environment
Buckingham et al. 1999). Likewise, although organic
programmes
farming is an agri-environment scheme and support is
co-funded by the EU under Regulation 2078/92, we do Differences in uptake rate of individual schemes largely
not consider the effects of organic farming as this has determine whether and where the overall objectives of
been discussed extensively elsewhere and the objectives agri-environment programmes can be met. In most
are not necessarily biodiversity conservation (Weibull, countries uptake is very unequally divided over the
Bengtsson & Nohlgren 2000; Mäder et al. 2002). 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
Design of agri-environment programmes across
are often unequally distributed geographically across
Europe
countries, with high uptake rates in areas with extensive
For clarity, in this review we distinguish between agri- agriculture and low uptake rates in areas where agri-
environment programmes, schemes and measures. We culture is more intensive (Emerson & Gillmor 1999;
consider an agri-environment programme to be the Buller & Brives 2000; Grafen & Schramek 2000). The
collection of schemes implemented in a country. Indi- mechanism resulting in this pattern is illustrated in
vidual schemes have different objectives (e.g. grassland Fig. 1(a), which shows that for extensive farmers par-
extensification or conservation of endangered livestock ticipation in an agri-environment programme is asso-
breeds) and regularly consist of a set of measures. For ciated with comparatively low costs of adaptation. Few
example, in the case of a grassland extensification changes are required to meet the requirements of the
scheme, measures (also called prescriptions) may con- schemes (Osterburg 2001). Thus, when uniform pay-
sist of a reduction in stocking densities or a cessation of ments per hectare (calculated on an average base) are
fertilizer inputs. offered for voluntary measures, most uptake will occur
Agri-environment programmes vary markedly be- in less favoured areas. The same mechanism probably
tween countries in Europe (Table 1). The objectives of explains why in most countries (especially France and
these programmes usually reflect a combination of the Austria) the low impact/low compensation schemes
main environmental, ecological and socio-economic are those with the highest uptake.
problems associated with agriculture, as well as the
political situation in each country. In Switzerland, the
The effects of agri-environment schemes on
Netherlands and the United Kingdom, schemes avail-
© 2003 British biodiversity
able to farmers concentrate on wildlife and habitat con-
Ecological Society,
Journal of Applied servation. In Denmark and Germany most schemes EU members are obliged to evaluate their agri-
Ecology, 40, offered to farmers aim to reduce agrochemical emis- environment programme with respect to their socio-
947–969 sions, while in France the programme is geared towards economic, agricultural and environmental aspects (Article950 Table 1. Characteristics of agri-environment programmes in European countries until the year 2000. Pilot agri-environment
D. Kleijn & 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
W. J. Sutherland
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
uptake: 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 uptake: 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 uptake: 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
© 2003 British
in the provinces of Bolzano, Trento and Valle d’Aosta, and is therefore virtually restricted to the alpine region. Highest uptake:
Ecological Society,
reduction of fertilizer and pesticides inputs (37% of AEP area) and maintenance of countryside and landscape (32%). Source:
Journal of Applied
INEA (1999).
Ecology, 40,
947–969951 Table 1. Continued
Ecological
Luxembourg. (UAA’95 126 900 ha; area with AES’97 97 000 ha; AEP since 1996). Only one scheme, available to all farmers in
effectiveness of
Luxembourg, had been implemented in 1997. This scheme addressed maintenance of the countryside and landscape. Source:
agri-environment Anonymous (1998).
schemes
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 uptake: 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 uptake: 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 uptake: 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 uptake: 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 uptake: 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).
16, EC Regulation 746/96). Currently, most evaluation environment schemes on the abundance or species rich-
studies simply examine uptake patterns of different ness of organisms. Initially, we performed an extensive
schemes within programmes. However, implementation literature review. However, as most evaluation studies
of schemes does not guarantee that the stated object- are published outside the mainstream scientific jour-
ives of the scheme will actually be met. Furthermore, nals, we also searched the internet and approached
the biodiversity and environmental objectives are rarely some 40 key people outside the Netherlands and the
© 2003 British
defined clearly at the outset, which hampers proper United Kingdom to ascertain whether they knew of
Ecological Society,
Journal of Applied evaluation in a number of countries (Schramek 2001). any evaluation studies in their country or of any person
Ecology, 40, Table 2 summarizes all those studies that we have who might have more information. Many studies
947–969 been able to locate that evaluate the effects of agri- claimed to evaluate the effects of schemes but simply952
D. Kleijn &
W. J. Sutherland
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.
described the status or trends of species of interest in The number of replicates varied from 1 to 398. The
the scheme site without any reference or control data. number of controls was often similar to the number of
These studies cannot be used to infer effects of the replicates but in some cases far larger or smaller (161
changes in management due to the agri-environment controls for 26 experimental replicates and, of greater
schemes, hence we did not consider them further in this concern, 2 controls for 82 experimental replicates).
review. Although we may have missed some studies, Two Swiss studies compared the spatial distribution of
we are confident that we have conducted a thorough birds over the landscape and analysed whether sites
search for studies throughout Europe. We located 62 with schemes were used by birds more than would be
studies from just six countries, of which 76% were from expected based on a random distribution. These stud-
just two countries (18 from the Netherlands and 29 ies did not contain formal control areas. The data from
from the United Kingdom). Only 27% (17) of the stud- 31% of the studies were not analysed statistically. Some
ies were published in international peer-reviewed jour- reports divided the analysis into a number of groups,
nals. Excluding the United Kingdom and Ireland, 83% such as common vs. Red List plant species. To avoid
of the studies were published in the national language replication and information overload we selected the
and remain therefore largely inaccessible to people out- measure (usually species richness) that seemed to best
side that country (Table 2, Table 3). 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-
The approaches to evaluation varied enormously, even paeus Pallas) while 29 (47%) studies investigated the
within individual countries, making it very difficult to response of birds.
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, Our results show that plant diversity may be difficult
nature reserves and conventional management with to enhance with agri-environment schemes (Table 2).
areas that were managed conventionally throughout Eleven of the 20 studies addressing botanical diversity
and usually were located outside ESAs. Other studies found positive effects of schemes whereas two studies
compared the pooled species diversity of all fields with reported negative effects. Considering the subsample
agri-environment schemes with the pooled species of 14 studies that subjected the data to some form of
diversity of all conventionally managed fields in a sin- statistical analysis, six studies demonstrated positive
gle area that consisted of a mosaic of scheme and con- and two studies demonstrated negative effects of
ventional fields. The same difficulties apply to the two schemes, the remaining seven studies finding no effect
other common study design, examining changes in bio- at all. The poor performance of the evaluated agri-
© 2003 British
diversity (26% of the studies) or trends in time in areas environment schemes with botanical objectives is in
Ecological Society,
Journal of Applied with and without schemes (32%). Only 34% of the stud- accordance with results of experimental studies. These
Ecology, 40, ies included baseline data, and 16% used a paired study generally show that it is extremely difficult to enhance the
947–969 approach to reduce environmental noise (Table 3). botanical diversity of intensively farmed agricultural953
947–969
schemes
Ecological
Ecology, 40,
© 2003 British
effectiveness of
Journal of Applied
agri-environment
Ecological Society,
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
Number Number
Investigated of of Statistical Base-line Duration
Country Scheme species (group) Design replicates controls analysis data study Results Notes Reference
CH ECA – Skylark Relative biotope 24 – Yes No 1995 Skylarks foraged more Weibel
wildflower use within skylark territories frequently and longer (1998)
strips territories in wildflower strips than in
any other biotope
CH ECA – Carabid beetles Comparison ECA 16, 7† 7 No No 1997 Higher number of species Pfiffner
extensive and control sites and red list species on et al.
grasslands extensive and low-intensity (2000)*
grasslands compared
to control
CH ECA Grass-hoppers Species richness and 62 398 Yes Yes 1990 & Proportion of ECA area ECA sites Hunziker
abundance on target 2000 relative to total area were perennial (2001)
sites and wider occupied by grasshoppers biotopes only
countryside before increased significantly for whereas controls
and after schemes seven species from 1990 to included
2000 arable fields
CH ECA – Grass-hoppers Species richness and 152 152 Yes Yes 1990 & Species richness and Peter &
extensive abundance on target 2000 abundance of individual Walter
grasslands and control sites species increased more (2001)*
before and on fields with ECA
after schemes
CH ECA Birds Spatial distribution 23 – Yes No 1998 & Five species (mostly Spatial Hofer et al.
of territories 1999 hedgerow species) more autocorrelation (2002)*,
relative to abundant, one species between ECA Spiess,
that of ECA sites less abundant on /near and vertical Marfurt
ECAs than expected structures. & Birrer
Explains part (2002)*
of the
observed effects
D Conservation Hoverflies and Comparison AES 2 2 No No 1988 Species richness and Raskin
headlands for carabid beetles and control sites abundance of hoverflies (1994)*
arable weeds and carabid beetles
higher on AES sites
(Cont’d )954
947–969
Ecology, 40,
D. Kleijn &
© 2003 British
W. J. Sutherland
Journal of Applied
Ecological Society,
Table 2. Continued
Number Number
Investigated of of Statistical Base-line Duration
Country Scheme species (group) Design replicates controls analysis data study Results Notes Reference
D Conservation of Black-tailed Population trends 2 2 No No 1989–98 Number of pairs inside Scheme areas Weiss
wet meadows godwit, curlew, inside/outside stable and outside declining include fields et al.
snipe AES area or inside declining less of nature (1999)*
rapidly than outside conservation
AES area organization
D Conservation of Waders Population trends 2292 ha 437 ha No No 1988–98 Number of pairs inside Scheme areas Ikemeyer
wet meadows inside/outside stable and outside declining include fields & Krüger
AES area or inside declining less of nature (1999)*
rapidly than outside AES conservation
area organization
D ‘Mittelgebirgs- Plants Changes in species 29 53 No Yes 1986 & Plant species richness Weis
programm’ – richness on fields with 1997 increases on fields with (2001)*
grassland and without AES AES and remains stable
extensification on control fields
D ‘Mittelgebirgs- Plants Trends in species 8 6 No Yes 1987–90, Plant species richness Weis
programm’ – richness on grazed 1994, increases slightly in grazed (2001)*
Resumed grazing AES fields and 1996 & plots on AES fields and
on abandoned exclosures that 1999 decreases sharply in
pastures serve as controls exclosures
D Grazing Plants, various Species richness 6 6 Yes No 1996 Plant diversity not different, Kruess &
extensification insect groups and abundance insect richness and Tscharntke
in a randomized abundance significantly (2002a,b)
block design higher on scheme sites
relative to control sites
EI REPS scheme Plants and Species richness 15 15 Yes No 1999 Plant species richness lower; Feehan,
carabid beetles in field boundaries carabid beetle richness Gillmor &
in grasslands on farms with similar to control farms Culleton
and without REPS (2002)
EI REPS scheme Plants and Species richness 15 15 Yes No 2000 Species richness of plants Feehan
carabid beetles in field boundaries and carabid beetles similar et al.
in tillage land on farms with on REPS and control (2002)
and without REPS farms955
947–969
schemes
Ecological
Ecology, 40,
© 2003 British
effectiveness of
Journal of Applied
agri-environment
Ecological Society,
Table 2. Continued
Number Number
Investigated of of Statistical Base-line Duration
Country Scheme species (group) Design replicates controls analysis data study Results Notes Reference
EI REPS scheme Farmland birds Species richness 5 5 Yes No 2000 Bird species richness Flynn
on farms with similar on REPS and et al. (2002)
and without REPS control farms
NL Botanical Plants Comparison of 35 9 No No 1984/85 Changes in species Most of the Altenburg
management changes on fields & 1990 richness/cover similar control fields &
agreements with and on AES fields and located outside Wymenga
without AES controls the ESA (1991)*
NL Meadow bird Meadow birds Comparison of 23 ha 81 ha No Yes 1988 & Trends in settlement Terlouw
agreements changes on fields 1991 densities similar on fields (1992)*
with and with and without AES
without AES
NL Meadow bird Meadow birds Comparison of 1 : 11 1 :7 Yes Partially 1986 − 90 1. Trends of two species 1. ESAs Van den
agreements trends (1) in ESAs 2 : 90 2 : 276 more positive and one include Brink &
and control species more negative in reserves Fijn
areas and (2) inside ESAs relative to outside 2. Prior to (1992)*
ESAs on fields with ESAs the scheme
and without schemes 2. Trends of lapwing more higher densities
positive on AES fields of three and
than control fields lower densities
of two species
were present
on AES fields
relative to control
fields
NL Botanical Plants Comparison of 45 – 169† 29 – 35† Yes Partially 1986 − 90 1. In ESAs more positive 1. ESAs Van den
management trends (1) in vegetation development include reserves Brink
agreements ESAs and control than outside ESAs in 2. Prior to & Fijn
areas and (2) inside both ditch banks and scheme ditch (1992)*
ESAs on fields with grasslands banks contain
and without schemes 2. Trends more positive less and grasslands
on AES fields than control more species on
fields in both ditch banks AES fields
and grasslands relative to controls
(Cont’d )956
947–969
Ecology, 40,
D. Kleijn &
© 2003 British
W. J. Sutherland
Journal of Applied
Ecological Society,
Table 2. Continued
Number Number
Investigated of of Statistical Base-line Duration
Country Scheme species (group) Design replicates controls analysis data study Results Notes Reference
NL Meadow bird Meadow birds Comparison of 119 ha 144 ha No No 1987−91 Population trends more Brandsma
agreements population trends positive on AES fields for (1993)*
on fields with and three species
without AES
NL Meadow bird Meadow birds Comparison of 122 ha 702 ha No No 1983, Population trends more Altenburg,
agreements population trends 1986, positive on AES fields Rebergen &
on fields with and 1989, for six species Wymenga
without AES 1992 & (1993)*,
1995 Uilhoorn
(1996)*
NL Botanical Vegetation Comparison of 255 ha 117 ha No No 1987 & Shift towards qualitatively Vegetation Wymenga,
management shifts in vegetation 1993 better vegetation classes broadly classified, Jalving &
agreements classes on fields between 1987 and 1993 significance of Jansen
with and more pronounced on results difficult (1994)*
without AES fields with AES to interpret
NL Meadow bird Meadow birds Comparison of 388 ha 420 ha No No 1985, Population trends less Most control Altenburg
agreements population trends 1987, negative on AES fields fields outside & Griffioen
on fields with and 1990 & for two species ESA in area with (1994)*
without AES 1993 woodlots
NL Botanical Vegetation Comparison of 26 161 Yes Yes 1990 & Nature Value Index Dijkstra
management changes in 1994 decreases significantly (1994)*
agreements ‘Nature Value in edges of fields
Index’s’ in edges without but stays stable
of fields with in edges of fields with
and without AES AES
NL Botanical Vegetation Comparison of shifts 86 ha 500 ha No No 1988 & Shift towards qualitatively Vegetation Ter Stege,
management in vegetation classes 1994 better vegetation classes broadly classified, Jalving &
agreements on fields with and between 1988 and 1994 significance of Wymenga
without AES more pronounced on results difficult (1995)*
fields with AES to interpret
NL Meadow bird Meadow birds Comparison of 115 ha 49 ha Yes No 1987, No significant differences Van Buel
agreements population trends 1990 between fields with and & Vergeer
on fields with and & 1993 without AES (1995)*
without AES957
947–969
schemes
Ecological
Ecology, 40,
© 2003 British
effectiveness of
Journal of Applied
agri-environment
Ecological Society,
Table 2. Continued
Number Number
Investigated of of Statistical Base-line Duration
Country Scheme species (group) Design replicates controls analysis data study Results Notes Reference
NL Botanical Plants Comparison of 14 14 No Yes 1989 & Trends in species richness/ Brongers
management changes on fields 1995 cover of (hay meadow) & Kolkman
agreements with and plant species more positive (1996)*
without AES on fields with AES
NL Meadow bird Meadow birds Comparison of 189 ha 462 ha No No 1995 Higher settlement densities Van Buel
agreements densities on fields of five species on (1996)*
with and AES fields
without AES
NL Field margin Insects Comparison of 12, 13† 12, 13† Yes No 1995 Higher number of insect taxa, Analysis makes Canters
strips and paired field margin and higher abundance of lady no distinction (1996)*
conservation strip/conservation bugs (Coccinellidae), dragon between
headlands headland with flies (Odonata), bumblebees conservation
conventional (Bombus spp.) and hover flies headlands and
crop edge (Syrphidae) on AES strips field margin strips
NL Botanical Fritillary Trends in abundance 71 32 Yes Yes 1990, Significant increase in Brongers
management (Fritillaria on fields with and 1994 juvenile plants on AES (1999)*
agreements meleagris) without AES & 1998 fields relative to controls
NL Meadow bird Birds, plants, Abundance and 7 7 Yes No 1998 One carabid beetle species Within ESAs Kleijn
agreements bees, hover species richness more abundant on fields two fields within et al.
and botanical flies, butterflies, on paired AES with AES a pair in (1999)*
management carabids and control fields relative to control sites environmentally
agreements similar areas
NL Meadow bird Birds, plants, Abundance and 39 39 Yes No 2000 Diversity and abundance of Within ESAs two Kleijn
agreements bees, hover flies species richness plants equal, that of insects fields within a et al.
and botanical on paired AES higher on fields with AES. pair in (2001,
management and control fields One bird species less environmentally in press)
agreements abundant on AES fields similar areas
NL Meadow bird Meadow birds Population trends 17 17 Yes partially 1989, Population trends similar Within ESAs Kleijn &
agreements on paired AES 1992 on AES and control fields two fields within Van Zuijlen
and control fields & 1995 a pair in (in press)
environmentally
similar areas
(Cont’d )958
947–969
Ecology, 40,
D. Kleijn &
© 2003 British
W. J. Sutherland
Journal of Applied
Ecological Society,
Table 2. Continued
Number Number
Investigated of of Statistical Base-line Duration
Country Scheme species (group) Design replicates controls analysis data study Results Notes Reference
P Castro Verde Steppe birds Changes in abundance 16 17 Yes Yes 1995 & Higher numbers of great Borralho
Zonal Plan of species in target and 1997 bustard, lesser kestrel and et al.
control sites little bustard in fields with AES (1999)*
UK North Peaks Birds Comparison of AES 1 1 Yes No 1994 –1996 Similar densities for eight ESA & control ADAS
ESA and control sites species but twite and in different regions (1997a)
lapwing much lower and surveyed in
in ESA different years
UK Breckland ESA Invertebrates, Comparison of 27 9 Yes No 1993 No significant differences ADAS
– conservation plants AES and control for a range of variables (1997b)
headlands sites
UK Radnor ESA – Plants Changes in target 16 19 Yes Yes 1994 & Significant increase ADAS
hay meadows and control plots 1997 in species richness in (1999b)
higher tier sites but
not in control or
lower tier
UK Radnor ESA – Plants Changes in target 15 20 Yes Yes 1994 & Significant increase in ADAS
wetlands and control plots 1997 species richness in higher (1999b)
tier sites but not in
control or lower tier
UK Ynys Môn Plants Changes in target 21 25 Yes Yes 1994 –1997 Significant increases in ADAS
ESA – coastal and control plots species suited to grazing (1999c)
habitats in AES stands contradicts
target but increase
in maritime species is
as required
UK Ynys Môn ESA Birds Comparison of 20 – Yes No 1995–1998 13 out of 15 wintering Sample sizes ADAS
population trends waders and waterfowl small for (1999a)
with those in wider decreased. Five of five breeding wader
countryside ‘target’ passerines and waterfowl
increased. Two of six (mean 2·5
breeding waders and territories in total)
waterfowl increased959
947–969
schemes
Ecological
Ecology, 40,
© 2003 British
effectiveness of
Journal of Applied
agri-environment
Ecological Society,
Table 2. Continued
Number Number
Investigated of of Statistical Base-line Duration
Country Scheme species (group) Design replicates controls analysis data study Results Notes Reference
UK Lleyn Peninsula Plants Changes in target 16 4 Yes Yes 1995 & Significant increase in ADAS
ESA – coastal and control plots 1998 species richness in controls (2001b)
grasslands but not in AES
UK Clwydian Range Plants Changes in target 82 2 Yes Yes 1995 & No significant difference ADAS
ESA – calcareous and control plots 1998 in species richness (2001a)
grasslands between years
or treatments
UK Clwydian Range Butterflies in Changes in target 4 1 No Yes 1995 & Numbers decreased by ADAS
ESA calcareous and control plots 1998 58% on sole control (2001a)
grassland transect but
increased by 13% on
AES sites
UK ESA – arable Grey partridge Population trends 1 1 Yes Yes 1970–1995 Greater declines on Aebischer
reversion in target and area with AES & Potts
control areas (1998)
UK Countryside Stone curlew Population trends 1 0 No Yes 1991–1999 Increase from 150 pairs Wardens also Aebischer
Stewardship before and after in 1991 to 233 in 1999 find nests of et al.
Scheme AES scheme after AES introduced. and ensure (2000)
Rapid decline between they are not
1940s and 1980s damaged by
farming operations
UK ESA – corncrake Corncrake Population trends 1 0 No Yes 1993–1998 4.2% annual increase Includes purchase Aebischer
initiative before and after after introduction scheme of nature reserves et al.
AES scheme (1992–98) compared to mainly for (2000)
3·5% annual decline corncrake
in reference period
(1988–93)
UK Pilot Arable Bumblebees Comparison of 84 84 Yes No 1999–2000 For four schemes higher Allen,
Stewardship paired sites and numbers in AES than Gundrey
controls. Carried controls. For one & Gardner
out for scheme none on AES. (2001)
various schemes Numbers generally low
(Cont’d )960
947–969
Ecology, 40,
D. Kleijn &
© 2003 British
W. J. Sutherland
Journal of Applied
Ecological Society,
Table 2. Continued
Number Number
Investigated of of Statistical Base-line Duration
Country Scheme species (group) Design replicates controls analysis data study Results Notes Reference
UK Regenerating Moorland birds Abundance and 12 12 Yes No 1996 –2000 Black grouse increased Baines
heather moors trends in areas (1176 ha) (1032 ha) 4·6% p.a. with AES but et al.
with and declined 1·7% p.a. in (2002),
without AES controls. Significantly Calladine
more females retained Baines &
broods in AES. Eight of Warren
11 species rarer in AES (2002)
(two significantly)
including black grouse.
Waders and other
gamebirds declined
faster in areas with AES
UK Pilot Arable Winter birds Farms with AES 54 48 Yes No 1998 –2000 Of 56 tests of groups Bradbury
stewardship and controls and areas four (2001),
significant positive Bradbury
effects and five & Allen
negative (2003)
UK Pilot Arable Breeding birds Farms with AES 25 24 Yes No 1999 –2000 Of 16 comparisons seven Bradbury
Stewardship and controls showed positive effect of & Allen
AES (one, lapwing (2003)
significant) and nine
negative effects
(three, woodpigeon,
sedge warbler and
rook significant)
UK ESA and Butterflies Abundance and 85 160 Yes No 1994 –2000 Equl numbers increased Over 50% sites Brereton,
Countryside trends in AES and decreased. Lower, owned by Stewart &
Stewardship and control sites but non significant decline conservation Warren
Scheme (12% v 15·5%) on AES organizations (2002)
sites. 10 of 13 specialist
species increased
(five significantly)961
947–969
schemes
Ecological
Ecology, 40,
© 2003 British
effectiveness of
Journal of Applied
agri-environment
Ecological Society,
Table 2. Continued
Number Number
Investigated of of Statistical Base-line Duration
Country Scheme species (group) Design replicates controls analysis data study Results Notes Reference
UK Barnacle Goose Barnacle goose Trends in abundance 16 0 Yes Yes 1990–2000 Numbers increased at a Authors suggests Cope
Management on reserve and areas proportionately higher numbers on et al.
Scheme without disturbance rate on AES sites than reserve reached (2003)
or limited on reserve. No capacity thus
disturbance difference in change increases elsewhere
before and after between undisturbed and could be due to
start scheme limited disturbance sites buffer effect
UK Pilot Arable True bugs Comparison AES 93 44 Yes No 1999–2000 Higher numbers on six Gardener
Stewardship sites and paired region /treatment et al.
controls combinations (2001b)
(4 significant). Lower
(not significant) in
remaining combination
UK Pilot Arable Carabid beetles Comparison 82–103† 31–34† Yes No 1999–2000 Of 29 region/treatment/date Gardener
stewardship various AES combinations higher numbers et al.
options and in AES for 14 (nine (2001a)
controls significant) and lower in five
(two significant). For carabid
larvae of 24 region/higher
treatment/date comparisons
15 higher in AES and nine
lower but none were significant
UK ESA – cereal Carabid beetles Comparison of 2 2 Yes No 1991 Of three carabids, two more Hawthorne,
headlands paired cereal abundant in AES, one more Hassall &
headlands with abundant in control Sotherton
or without AES (1998)
UK Countryside Cirl bunting Trends in bird 47 47 Yes Yes 1992–1998 Increased by 82% on Peach
Stewardship numbers inside land in scheme but by et al.
Scheme scheme or outside 2% on controls (2001)
within 47 tetrads
UK Pilot Arable Sawflies Comparison of sites 224 188 Yes No 1999–2000 No obvious effect on No distinction Reynolds
Stewardship with AES and sawfly abundance but made between (2001)
adjacent controls diversity higher seven different
on AES scheme options
(Cont’d )962
947–969
Ecology, 40,
D. Kleijn &
© 2003 British
W. J. Sutherland
Journal of Applied
Ecological Society,
Table 2. Continued
Number Number
Investigated of of Statistical Base-line Duration
Country Scheme species (group) Design replicates controls analysis data study Results Notes Reference
UK ESAs – raised Waders Comparison of 8 4 No Yes 1992–1997 Wader numbers increased Monitored since Chown
water levels trends in AES in three AES sites, stable 1989, schemes (1998)
and control sites in four AES sites, started 1992
decreased in three AES
sites and in four controls
UK Breckland Carabid beetles, Comparison of 3 2 Yes No 1988 For all groups higher Cardwell,
ESA – cereal spiders, uncropped abundance and more Hassall &
headland Heteroptera headlands species than control in White
management and cereal uncropped AES headlands (1994);
headlands but only for Heteroptera Hassall
with reduced in AES with reduced et al.
pesticide input pesticide inputs (1992);
with controls White
& Hassall
(1994)
UK Breckland Carabid beetles Comparison of 4 2 Yes No 1991 More species and Hawthorne
ESA – cereal paired cereal diversity than control & Hassall
headland headlands with in uncropped (1995)
management or without AES AES headlands but not
in AES with reduced
pesticide inputs
UK Pilot Arable Brown hare Comparison of 41 38 Yes No 1999 –2000 No difference detected Tapper
Stewardship farms with AES in numbers (2001)
and controls
UK ESA Breeding skylark Comparison of 25 –227† 41– 49† Yes No 1994 –1996 For downland reversion Wakeham-
AES and controls scheme 3–6 times as Dawson
in two ESAs many skylarks on AES et al. (1998)
as on controls. For
permanent
grassland reversion AES
had significantly fewer
skylarks for one but
significantly more for
another time period963 Table 3. Summary of all studies that were published, in
Wakeham-
Dawson &
Ecological congress proceedings or in reports. Percentages are given in
Aebischer
Reference
effectiveness of relation to the total of 62 studies
(1998)
agri-environment
Total studies 100%
schemes
Published in peer reviewed journals 27%
In national language* 83%
Have control sites 90%
Have replication 77%
Notes
Use statistical tests of significance 69%
Analyse changes between two points in time 26%
Analyse trends in time 32%
Have paired scheme and control sites 16%
Have baseline data 34%
Controls, replication and statistical analysis 58%†
permanent grassland
Controls, replication, statistical analysis 39%‡
reversion and fewest
cereal stubbles, then
Highest number on
downland, then far
and reduced bias§
fewer on AES of
AES of reverted
on winter wheat
*Excluding 32 studies from UK and Ireland.
†Including four studies with just two replicates.
Results
‡Including three studies with just two replicates.
§Bias 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.
Duration
1994 /5 –
1996 /7
study
fields (Berendse et al. 1992), particularly when the
Statistical Base-line
period of intensive use has been long enough to deplete
the local seed bank (Bekker et al. 1997).
data
No
The diversity of arthropods appears to be much
easier to enhance through implementation of agri-
analysis
environment schemes than other groups. Fourteen of
Yes
20 studies reported significant increases in the number
of species and three reported significant increases for
Number
controls
113 – 117† 40 – 47†
some and decreases for other species in response to
agri-environment schemes. Considering only those
of
studies that included statistical tests yielded similar
replicates
results. Of 17 studies, 11 found positive effects, three
Number
both positive and negative effects, and the remaining
of
three studies did not find any effects of schemes. Kleijn
†Numbers of replicates differ depending on type of scheme or sampling date.
et al. (2001) and Kruess & Tscharntke (2002a,b) found
no increase in plant species richness, but nevertheless
AES and controls
reported significant increases in insect diversity on
Wintering skylarks Comparison on
fields with agri-environment schemes. This positive
in two ESAs
effect may be due to reduced levels of disturbance on
Design
less intensively used fields, allowing organisms to com-
plete their life cycle before the vegetation is removed by
mowing or grazing (Kruess & Tscharntke 2002a). As
with plants, increased diversity is usually due to more
species (group)
common species. However, Hunziker (2001) and Peter
Investigated
& Walter (2001) found that Ecological Compensation
Areas in Switzerland significantly enhanced the number
*Published in the national language.
and abundance of endangered grasshopper species.
Their studies furthermore indicated the importance
of nearby source populations, for instance in nature
conservation areas, for achieving positive effects of
conservation management on farmland (see also
Table 2. Continued
Scheme
Duelli & Obrist 2003).
ESA
© 2003 British
The studies investigating the effects of agri-environment
Ecological Society,
schemes on birds show no consistent pattern. Thirteen of
Country
Journal of Applied
Ecology, 40, 29 studies reported positive effects of agri-environment
UK
947–969 schemes on bird species richness or abundance, two reportedYou can also read
