Effect of ecological compensation areas on floristic and breeding bird diversity in Swiss agricultural landscapes F. Herzog a, * , S. Dreier a , G. Hofer a , C. Marfurt b , B. Schu ¨pbach a , M. Spiess b , T. Walter a a Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Reckenholzstrasse 191, CH-8046 Zurich, Switzerland b Swiss Ornithological Institute, CH-6204 Sempach, Switzerland Abstract In the 1990s the Swiss agricultural policy was reformed and new environmental objectives were formulated. The aims of the reform were to halt the loss of agro-biodiversity and to enable the spread of endangered species. As a result, the utilised agricultural area (UAA) is now interspersed with low input ecological compensation areas (ECA), making up 13% of the UAA (extensified grassland 90,000 ha, traditional orchards 25,000 ha, hedgerows 3000 ha, other elements 23,000 ha). To assess whether ECA contribute to the enhancement of biodiversity, plant composition was recorded on 1914 ECA of the Swiss plateau and 1966 territories of 27 bird species, which typically breed in open and semi-open farmland, were mapped and related to ECA. Eighty-six percent of ECA litter meadows and 50% of ECA hedgerows were of good ecological quality and attracted wetland and hedgerow birds. Most ECA hay meadows and traditional orchards, on the other hand, still reflected their former intensive management with only 20 and 12%, respectively, being of good ecological quality. Hardly any benefits for grassland and orchard birds were observed. Ecological quality of ECA was generally higher in the bio-geographical region ‘Basin of Lake Geneva and Upper Rhine Valley’ than in the other two regions of the Swiss plateau and it was higher in the agricultural production zone ‘Pre- alpine Hills’ than in the ‘Lowland Zone’. # 2005 Elsevier B.V. All rights reserved. Keywords: Agri-environment scheme; Biodiversity; Grassland; Hedgerow; Orchard; Policy evaluation; Breeding birds; Vegetation 1. Introduction Modern, industrialised agricultural production has boosted food security, but to a great extent it has done so at the expense of the environment. In the early 1990s the increased awareness of environmental damage caused by agriculture together with the growing costs for the regulation of agricultural markets led to the introduction of agri-environment schemes. In Switzerland as in other countries, there was an animated public debate on the cost of government expenses for the support of agriculture www.elsevier.com/locate/agee Agriculture, Ecosystems and Environment 108 (2005) 189–204 * Corresponding author. Tel.: +41 1 377 74 45; fax: +41 1 377 72 01. E-mail address: [email protected] (F. Herzog). 0167-8809/$ – see front matter # 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.agee.2005.02.003
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Effect of ecological compensation areas on floristic and
breeding bird diversity in Swiss agricultural landscapes
F. Herzog a,*, S. Dreier a, G. Hofer a, C. Marfurt b,B. Schupbach a, M. Spiess b, T. Walter a
a Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture, Reckenholzstrasse 191,
CH-8046 Zurich, Switzerlandb Swiss Ornithological Institute, CH-6204 Sempach, Switzerland
Abstract
www.elsevier.com/locate/agee
Agriculture, Ecosystems and Environment 108 (2005) 189–204
In the 1990s the Swiss agricultural policy was reformed and new environmental objectives were formulated. The aims of the
reform were to halt the loss of agro-biodiversity and to enable the spread of endangered species. As a result, the utilised
agricultural area (UAA) is now interspersed with low input ecological compensation areas (ECA), making up 13% of the UAA
(extensified grassland 90,000 ha, traditional orchards 25,000 ha, hedgerows 3000 ha, other elements 23,000 ha). To assess
whether ECA contribute to the enhancement of biodiversity, plant composition was recorded on 1914 ECA of the Swiss plateau
and 1966 territories of 27 bird species, which typically breed in open and semi-open farmland, were mapped and related to ECA.
Eighty-six percent of ECA litter meadows and 50% of ECA hedgerows were of good ecological quality and attracted wetland
and hedgerow birds. Most ECA hay meadows and traditional orchards, on the other hand, still reflected their former intensive
management with only 20 and 12%, respectively, being of good ecological quality. Hardly any benefits for grassland and orchard
birds were observed. Ecological quality of ECA was generally higher in the bio-geographical region ‘Basin of Lake Geneva and
Upper Rhine Valley’ than in the other two regions of the Swiss plateau and it was higher in the agricultural production zone ‘Pre-
(–) Indicates statistics not computed because the number of expected territories is <5.a Total number of territories per bird species and ecological group as observed and as expected on the basis of the ECAs’ share of farmland
(17%, including a 25 m buffer around ECAs).* p < 0.05.
** p < 0.01.*** p < 0.001.
management of steep agricultural land tends to reduce
the risk of soil erosion and nutrient run-off.
Farmers had a clear preference for allocating ECA
near forests edges where shade reduces yield and
management options (Table 2c).
The Swiss by-law for water pollution control
prohibits the use of fertilizers and pesticides on a 3 m
buffer strip along streams and rivers and these buffer
strips would be predisposed for ECA. Table 2d
indicates that generally this is not the case, except for
individual municipalities where the allocation of ECA
was integrated in an overall planning process.
4.2. Ecological quality of ECA
4.2.1. Value systems
Assessing the ecological quality of a habitat is not
straight forward and depends on the value system and
objectives. With respect to agricultural landscapes,
Duelli and Obrist (2003) distinguish between the
F. Herzog et al. / Agriculture, Ecosystems and Environment 108 (2005) 189–204 201
objectives of: (i) species conservation (focus on rare
species); (ii) ecological resilience (focus on diversity
of species); and (iii) biological control of potential
pest organisms (focus on predators and parasitoids).
The Swiss agri-environment programme aims at
objectives (i) and (ii). The quality requirement for
objective (i) was defined as the number of endangered
species. The quality requirement for objective (ii)
could be the number of species found on ECA as
compared to control sites. This approach was applied
for the assessment of the effectiveness of ECA with
respect to breeding birds. With respect to vascular
plants, it was possible to adopt a normative approach
because the by-law on ecological quality (BLW, 2001)
provides guidelines on the target vegetation of ECA.
Thus, the results are highly relevant for the policy
maker. However, the ecological quality as defined in
the by-law is the result of a combined scientific and
political process also influenced by pragmatic con-
siderations (e.g. facilitating the control of the quality
criteria). Therefore, in addition and as a control for the
validity of this assessment, we compared the species
composition of grassland ECA with a typology, which
reflects the intensity of management.
Only very few Red List plant species were found
(Table 3) and therefore, ECA hardly contribute to the
preservation of endangered species. If this were the
only criterion to evaluate the success of the ECA
scheme we would have to conclude that its perfor-
mance is rather poor.
4.2.2. ECA grasslands
Up to 92.2% of the ECA litter meadows were found
to meet the requirements of the by-law on ecological
quality. In contrast, the share of ECA hay meadows
(which make up 59% of all ECA in Switzerland),
which met the requirements of the by-law, was as low
as 13.5% in the ‘Lowland Zone’ of the ‘Eastern
Central Plateau’ and never above 50% (Tables 4a and
5b). The differences in the botanical quality between
those two ECA grassland types were also reflected by
the distribution between the different intensity types of
grassland management (Fig. 3). In accordance to these
findings, the bird mappings showed that wetland birds
took advantage of ECA whereas the territories of birds
of open agricultural landscapes, where grassland ECA
mostly consists of ECA hay meadows, were not more
frequent on or near ECA (Table 5). The structure and
botanical quality of most ECA hay meadows still
reflected their former intensive utilisation and the late
cut did not suffice to make these usually dense stands
suitable for bird nesting. Moreover, many ECA
meadows were located along vertical structures such
as forest edges (Table 2c), which openland birds tend
to avoid. For arthropods, on the other hand, case
studies showed a more rapid reaction to the ‘offer’ of
ECA than the vegetation (Pfiffner and Luka, 2000;
Peter and Walter, 2001; Schupbach et al., 2002;
Jeanneret et al., 2003a,b,c). This mitigates the
negative assessment of ECA hay meadows and
demonstrates the necessity to investigate several
biodiversity indicator groups.
4.2.3. ECA hedgerows
Of the 35,000 ha of hedgerows in Switzerland
(BFS, 1997) only about 10% are inscribed as ECA by
farmers. This percentage is relatively low even when
considering that not all existing hedges are actually
owned by farmers. In the different study regions
between 28.4 and 81.9% of ECA hedges were assessed
as ‘quality hedges’ according to BLW (2001)
(Table 4c). The structure of the vegetation, the share
of thorny shrubs, the occurrence of dead wood and the
number of cavities in trees play an important role in
their potential attractiveness for animals (Zwolfer
et al., 1984; Baudry et al., 2000). There were
significantly more hedgerow bird territories than
expected in or near hedgerows (Table 5) and hedgerow
birds also seem to take advantage of nearby ECA
grasslands, which improve their foraging conditions.
4.2.4. ECA orchards
Between 1951 and 2001 the number of standard
fruit trees in traditional orchards has been reduced by
79% (BFS, 2002a, b). In the meantime almost 90% of
the remaining 3 � 106 trees are inscribed in the ECA
scheme but the replanting rate of orchards seems to be
insufficient to ensure their long-term existence. Only
few traditional orchards complied with the require-
ments of the by-law on ecological quality (BLW,
2001) (Table 4d) and only one orchard bird species
(green woodpecker) was found more frequently in or
near traditional orchards (Table 5). Pozzi (2004)
analysed the diversity and abundance of spiders in
traditional orchards in a case study region. He found
that they contributed to the preservation of rare and
F. Herzog et al. / Agriculture, Ecosystems and Environment 108 (2005) 189–204202
typical spider species. Also, traditional orchards are
part of the landscape heritage in several regions of the
Swiss plateau, especially so in the ‘Basin of Lake
Geneva and Upper Rhine Valley’. They are relevant
for landscape scenery and for public acceptance of the
agricultural sector (Herzog and Oetmann, 2001;
Schupbach, 2001) and potentially beneficial for the
landscape water and nutrient balance (Herzog, 1998).
4.2.5. Regional aspects
There were significant differences between bio-
geographical regions. The ecological quality of ECA
hay meadows, hedgerows and orchards was generally
higher in the ‘Basin of Lake Geneva and Upper Rhine
Valley’ than in the other two bio-geographical regions.
This can be explained by the specific climatic and
pedological conditions. The species pool contains more
of the target species which are considered ‘valuable’ in
the Swiss context and which are therefore used as
indicators for ecological quality. Moreover, the soil
quality is generally lower and agricultural management
is therefore less intensive. ECA litter meadows almost
exclusively occurred on the ‘Eastern Central Plateau’.
There were also differences between the agricul-
tural production zones within the bio-geographical
regions. We consider that the generally higher
ecological quality of ECA in the ‘Pre-alpine Hills’
is due to higher topographical variability which limits
both the intensity of agricultural production in terms
of inputs as well as the creation of uniform agricultural
landscapes with large fields.
5. Conclusions
The Swiss agri-environmental policy has caused
significant changes in farmers’ practices, which go
beyond legal requirements, and so-called best practices.
The fact that almost each farmer has assigned 7% of his
or her UAA as ecological compensation must be
considered as a major achievement. Based on our
findings on the scheme’s effectiveness, the following
conclusions are drawn and recommendations made:
� M
ost ECA hay meadows still reflected the former
intensive management. The quality of the vegeta-
tion of 51–87% of the ECA meadows (depending on
bio-geographical region and agricultural production
zone) did not correspond to traditional hay
meadows (Fig. 3); their location and structure did
generally not enhance populations of meadow birds.
About 7–19% of the ECA meadows could
potentially restore to traditional hay meadow
composition. Farmers should be encouraged to
engage in their long-term extensive management.
� T
he vegetation of most ECA litter meadows
corresponded to the target vegetation composition
and to the requirements of the by-law on ecological
quality (BLW, 2001); breeding birds were more
frequent on or near this ECA type. ECA litter
meadows should further be supported.
� O
nly few hedgerows are actually inscribed in the
ECA scheme. On average, 50% were of good
ecological quality and hedgerows proved to be
advantageous for hedgerow birds. Additional funds
for the management of hedgerows would make this
ECA-type more attractive for farmers, help to
secure the existing hedges and at the same time
increase their ecological quality.
� T
he undergrowth of traditional orchards reflected
the intensive utilisation of these grasslands (mostly
pastures) and hardly contributed to the conservation
of floristic diversity. Only one orchard bird was
significantly more frequent in ECA orchards than
expected. Although the ECA scheme apparently
contributes to preserve standard fruit trees, the age
structure of orchard stands indicates that replanting
is insufficient. We suggest that extension activities
be concentrated on traditional orchards in order to
improve their environmental performance.
Our results are limited to the Swiss plateau and
cannot be extrapolated to the whole of Switzerland, as
there are significant differences between bio-geogra-
phical regions and agricultural production zones. A
consolidated monitoring and evaluation programme,
which is representative for the entire country is pre-
sently lacking; propositions have been made by Daniel
et al. (2003).
Acknowledgements
We thank Stephanie Aviron, Simon Birrer, Philippe
Jeanneret and Lukas Kohli for their comments on
preliminary manuscript versions, Debra Bailey for
F. Herzog et al. / Agriculture, Ecosystems and Environment 108 (2005) 189–204 203
correcting the language and Mikko Kuusaari and
Gwenaelle Le Lay for reviewing the content and
suggesting improvements. The Swiss Federal Office
for Agriculture and the Swiss Federal Office for
Environment, Water and Landscape funded part of the
work.
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