Agriculture, Ecosystems and Environment 77 2000 101–109
Species diversity as a task for organic agriculture in Europe
Thomas van Elsen
∗
Department of Ecological Agriculture, University of Kassel, Nordbahnhofstr. 1a, D-37213 Witzenhausen, Germany Accepted 19 July 1999
Abstract
Different levels of biodiversity — species, biotopes and landscapes — can be differentiated and used for the assessment of the biotic environment of organic farms. Could the integration of species diversity into the cultivated land be a task for
organic farming in the future? For hundreds of years agriculture supported the enrichment and the diversification of the vegetation in Central Europe. Nowadays many landscape elements are no more than relics of historical land use. Todays’
intensive agriculture is considered to be the main agent responsible for the decline of plant species. What are the effects of sustainable ways of agriculture on biodiversity, especially on the diversity of arable field plants? Many investigations show
positive effects of organic agriculture on the diversity of arable fields and grassland, too. A higher number of species and also more endangered ‘red list’ species are to be found in organic fields. Different effects of agricultural practices in organic
farming on the weed flora are discussed.
Today economic pressure leads to an improvement in mechanical weed control and undersowing. This shows that the aim of preserving, supporting and developing a diverse arable field flora cannot be reached automatically by converting to organic
farming: an integration with the guiding image of organic agriculture is needed. Measures to support the richness of species of arable field plants in organic fields are shown.
Many organic farmers are aware of correlations between an impoverished landscape and the appearance of pests and diseases and try to enrich the landscape with biotopes. Despite all the benefits of organic farming for nature the danger of separation
arises in organic farming too: the separation of the landscape into 5 ‘biotopes’ where nature is allowed to develop and into 95 ‘production area’ being used intensively. One step further would be the development from separation to integration
of biodiversity into the method of organic farming as a whole — a way which corresponds with modern aims of the nature conservation movement. The ‘integrated table of landscape quality aspects’ developed during the work of the concerted action
‘The Landscape and Nature Production Capacity of OrganicSustainable Agriculture’ could be useful for the assessment of organic farms under various aspects of biodiversity. It might help to change the farmers’ viewpoint and make them assess their
particular landscape values and their landscape components with new eyes. ©2000 Elsevier Science B.V. All rights reserved.
Keywords: Biodiversity; Weeds; Arable field plants; Organic farming; Species diversity; Vegetation; Landscape; Nature conservation; Biotopes
∗
Corresponding author. Tel.: +49-5542-981-655; fax: +49-5542-981-568
E-mail address: velsenwiz.uni-kassel.de T. van Elsen
1. Introduction
Organic agriculture tries to produce healthy food under environmentally sound conditions. In recent
years a lot of research has been carried out on organic agriculture’s effects on biodiversity i.e., Youngberg
et al., 1984; Isart and Llerena, 1996. Furthering
0167-880900 – see front matter ©2000 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 7 - 8 8 0 9 9 9 0 0 0 9 6 - 1
102 T. van Elsen Agriculture, Ecosystems and Environment 77 2000 101–109
bio-genetic diversity is pointed out as an important target in the ‘integrated table of landscape quality as-
pects’ developed during the work of the concerted ac- tion ‘The Landscape and Nature Production Capacity
of OrganicSustainable Agriculture’ van Mansvelt, 1997. Different levels of biodiversity — species,
biotopes and landscapes — can be differentiated and used for the assessment of the biotic environment
of organic farms as shown in the second column of this table mentioned above. As a specification of this
certain aspect in the paper presented different levels of supporting biodiversity in the landscape of organic
farms will be discussed, with emphasis on the ques- tion, if and why the integration of species diversity
into agricultural holdings could be a task for organic farming in the future.
2. Landscape and agriculture — a historical view
For hundreds of years agriculture has not only pro- duced food for human beings; it has had a high ‘land-
scape and nature production capacity’ van Mansvelt and Stobbelaar, 1995 as well. After the last Ice Age
ended more than 10 000 years ago, the vegetation in Central Europe became dominated by woodlands.
Due to the seasonal rhythm the different rocks and soils were colonized by plants; without disturbance
the succession tends toward a vegetation dominated by woods.
The beginning of woodland clearance introduced a phase of anthropogenous enrichment and differentia-
tion of vegetation Pott and Hüppe, 1991. In wood- lands, ecological variations of different areas are di-
minished by the microclimate, whereas the different soil conditions are very important for the diversifica-
tion of the plant communities that follow after clearing the trees. A wide spectrum of different ways of us-
ing the land followed after clearing; by replacing most of the woods and through the introduction of agricul-
ture the diversity of plant and animal species in the landscape increased Hüppe, 1990. In a process tak-
ing hundreds of years the natural landscape changed into a ‘cultural’ rural landscape that allowed more
species to live. The landscape was divided into settle- ments with gardens, stone walls and livestock breed-
ing and — around the villages — into arable land, or- chards, grassland and hedgerows, which connected the
remaining woods with the agricultural landscape. On shallow limestone pastures grazed by sheep, Mediter-
ranean species like orchids appeared, which also at- tracted new insect species. In the fields, grain species
were followed by weeds having their origin in the Mediterranean area and the Middle East. Only a few of
these ‘arable field plants’ were real ‘problem weeds’ for the farmers.
The different management of grassland produced a strong diversification. On meadows being cut only
once a year a different vegetation can develop than on grassland that is mown twice or three times. Pastures
with different systems of grazing lead toward a great variety of typical plant communities Fig. 1. On the
arable land, different communities of weed species ap- pear not only due to the different types of soil: the
combination of species differs in a typical way depend- ing on whether the field is ploughed in autumn or in
springtime van Elsen, 1994a. Also, in former times the use of manure led to an increase in diversity in the
landscape van Elsen, 1994b. Even forms of agricul- ture that caused environmental problems and could be
considered as anything but sustainable cf. Makowski and Buderath, 1983 contributed to the enrichment of
biodiversity. One reason for this was that due to the lack of technical tools human beings did not have the
ability to destroy aspects of nature Falter, 1992. Dif- ferent regions vary with respect to their customs, tra-
ditional costumes, dialects, structure of the villages and types of farmhouses Ellenberg, 1990. Peoples’
and their different ways of farming also influenced the cultural landscapes that developed out of the natu-
ral landscape. Until the industrialization of agriculture began, mans’ shaping of nature resulting out of his
essential needs, Konold, 1996 resulted in an increase of biodiversity in the Central European landscape.
Nowadays, many landscapes with lots of diverse elements are little more than relics of this historical
land use. On the one hand in landscapes with rich soils, large fields and fewer crops left less space for
wildlife. Shrubs were removed, ponds were drained, and few animals and plants could survive the regular
spraying with chemicals. On the other hand, regions with poor soils were abandoned by agriculture. In this
situation, a lot of species that are dependent on agri- cultural land use disappear within a few years. For
example, the spectrum of arable field plants on rich loess fields has been reduced to a few problem weeds,
T. van Elsen Agriculture, Ecosystems and Environment 77 2000 101–109 103
Fig. 1. Traditional agriculture lead to an increase of biodiversity in the landscapes.
whereas shallow limestone soils become abandoned, supported by set-aside programs. In many cases such
fields were the last reserves for annual field plants — without regular ploughing annual weeds disappear
and perennial plants take over van Elsen and Gün- ther, 1992. A similar development on the grassland
takes place. Through the use of mineral fertilizer and early cutting the spectrum of plants has been reduced
to a few species, while mowing or grazing of grass- land with low yields is not profitable anymore: shrubs
and trees take over, and biotopes for a lot of plants and animals disappear. The effects of today’s agricul-
ture are the opposite of agriculture’s former tendency which allowed a development from the natural land-
scape toward the mosaic of Central European cultural landscapes. Today agriculture is considered to be the
main agent for the decline of plant species in Germany. An analysis of the Red List of extinct, missing and
endagered wild plants by Korneck and Sukopp, 1988 shows that agriculture is responsible for the decline
of 513 out of 711 species that were evaluated. Of all endagered plant species 10.8 are arable field plants,
in addition, 15 ‘weed’ species have already become extinct =25 of all extinct plant species.
3. Effects of organic farming on arable field plants
