**4. Meta-analysis on different taxa**

The above indicates there is enough evidence that agriculture has become much more intensive during recent decades and simultaneously there has been a drastic decline in biodiversity in agroecosystems. This means that biodiversity in agroecosystems is negatively correlated with AI. However, correlation does not necessarily mean causation, and therefore – in theory – the decline in biodiversity in agroecosystems might have been caused by other factors and from a practical point of view, the effects of these should be minimized. This doubt provoked abundant case studies on how exactly AI can affect biodiversity of particular groups of organisms. The results of such studies, however, are

Biodiversity Drifts in Agricultural Landscapes 321

Feehan et al., 2005 x x Geiger et al., 2010 x x x

Gibson et al., 2007 x Hald, 1999 x

Hyvönen et al., 2003 x

Kleijn et al., 2001 x x x Kleijn et al., 2004 x x x Kleijn et al., 2006 x x x Knop et al., 2006 x x

Delgado & Moreira, 2010 x

Daz & Telleria, 1994 x Doxa et al., 2010 x

Genghini et al., 2006 x

Kleijn & van Zuijlen, 2004 x

Ottvall & Smith, 2006 x Peach et al., 2001 x

Wilson et al., 2007 x

biodiversity for the four groups of organisms studied.

Di Giulio et al., 2001 x

Duelli et al., 1999 x

Hasken & Poehling, 1995 x Hendrickx et al., 2007 x Hodgson et al., 2010 x Holzschuh et al., 2007 x Hutton & Giller, 2003 x

Kremen et al., 2002 x Melnychuk et al., 2003 x Östman, 2002 x

Pfiffner & Luka, 2003 x

Roschewitz et al., 2005a x Roschewitz et al., 2005b x Rundlof & Smith, 2006 x Rundlöf et al., 2008 x Schmidt et al., 2005 x

Shah et al., 2003 x Thorbek & Bilde, 2004 x Weibull et al., 2000 x

Pocock & Jennings, 2008 x x

Schmitzberger et al., 2005 x

Weibull et al., 2003 x x

Table 1. References to studies used in the meta-analysis of the relationships between AI and

Wickramasinghe et al., 2003 x Wickramasinghe et al., 2004 x

contradictory and many are inconclusive. Because there is now a great number of these studies the results need to be summarized and patterns revealed. Although there are several such reviews, none of them analyze the situation in its entirety, which is the task of this section.

We searched the Web of Science using the following key-words: agriculture intensification; organic agriculture; agro-environmental schemes; effects of agriculture; landscape composition; land use; biodiversity. The search was restricted to studies on invertebrates, birds, plants and mammals. We then categorized them according to their conclusion regarding the relationship between AI or Landscape composition and biodiversity as having a positive, negative, none or mixed effect. We used 54 studies for determining the relationships between AI and biodiversity and 36 for those between landscape composition and biodiversity. If a study considered more than one taxon, more than one parameter (e.g. diversity and abundance) or more than one measure of comparison (e.g., AI and landscape composition) we treated them as independent studies. During this procedure, all reviews and studies containing only models or did not provide a clear statement allowing us to categorize them into one the four categories, were excluded.

When categorizing, we have always respected the conclusions formulated by the authors, even if we did not always agree with them, because introducing our personal views could have affected the outcome of our analyses. We accepted all measures of diversity used in the papers studied, which includes the number of species, diversity indexes, and even number of individuals in the group studied, even though we do not consider the latter as valid, because the number of individuals can be affected by one or a few dominant species, adapted to the particular conditions.

There was a wide variety of measures of AI in the papers. These include usage/absence of pesticides and/or artificial fertilizers, amounts of pesticides/fertilizers used, intensity of tillage, comparison of organic vs. conventional farms, grazing intensity or comparison of extensive vs. intensive cropping. Measures of landscape composition, include, more or less heterogeneity, land use, average size of fields, percentage and size of arable land and/or non-crop habitats in the landscape. In table 1 are the reference to the studies used in the meta-analysis of the relationship between AI and Biodiversity.


contradictory and many are inconclusive. Because there is now a great number of these studies the results need to be summarized and patterns revealed. Although there are several such reviews, none of them analyze the situation in its entirety, which is the task

We searched the Web of Science using the following key-words: agriculture intensification; organic agriculture; agro-environmental schemes; effects of agriculture; landscape composition; land use; biodiversity. The search was restricted to studies on invertebrates, birds, plants and mammals. We then categorized them according to their conclusion regarding the relationship between AI or Landscape composition and biodiversity as having a positive, negative, none or mixed effect. We used 54 studies for determining the relationships between AI and biodiversity and 36 for those between landscape composition and biodiversity. If a study considered more than one taxon, more than one parameter (e.g. diversity and abundance) or more than one measure of comparison (e.g., AI and landscape composition) we treated them as independent studies. During this procedure, all reviews and studies containing only models or did not provide a clear statement allowing us to

When categorizing, we have always respected the conclusions formulated by the authors, even if we did not always agree with them, because introducing our personal views could have affected the outcome of our analyses. We accepted all measures of diversity used in the papers studied, which includes the number of species, diversity indexes, and even number of individuals in the group studied, even though we do not consider the latter as valid, because the number of individuals can be affected by one or a few dominant species,

There was a wide variety of measures of AI in the papers. These include usage/absence of pesticides and/or artificial fertilizers, amounts of pesticides/fertilizers used, intensity of tillage, comparison of organic vs. conventional farms, grazing intensity or comparison of extensive vs. intensive cropping. Measures of landscape composition, include, more or less heterogeneity, land use, average size of fields, percentage and size of arable land and/or non-crop habitats in the landscape. In table 1 are the reference to the studies used in the

**Relationship between AI and biodiversity Birds Invertebrates Mammals Plants** 

Burel et al., 1998 x x x x Clough et al., 2007a x x

categorize them into one the four categories, were excluded.

meta-analysis of the relationship between AI and Biodiversity.

Ameixa & Kindlmann, 2008 x Batáry et al., 2007 x

Blackburn & Wallace, 2001 x

Brittain et al., 2010 x

Clough et al., 2007b x Cole et al., 2005 x

Benton et al., 2002 x

Bradbury et al., 2004 x

Davey et al., 2010 x

Bates & Harris, 2009 x

Davy et al., 2007 x

adapted to the particular conditions.

of this section.


Table 1. References to studies used in the meta-analysis of the relationships between AI and biodiversity for the four groups of organisms studied.

Biodiversity Drifts in Agricultural Landscapes 323

Figure 4 shows the frequencies of papers listed in Table 2, claiming different effects (positive, negative, no effect or mixed) of landscape structure on biodiversity. Similarly, there is no clear pattern in the results, except for the significantly larger number of papers claiming a positive effect of landscape structure on biodiversity of invertebrates, compared

**Landscape structure and biodiversity Birds Invertebrates Mammals Plants** 

Burel et al., 1998 x x x x

Gibson et al., 2007 x

Kleijn et al., 2004 x x x

Schmitzberger et al., 2005 x

Weibull et al., 2003 x x

Table 2. References to studies used in the meta-analysis dealing with the relationship between landscape structure and biodiversity of the four groups of organisms studied.

Wickramasinghe et al., 2003 x

with the other groups of organisms studied.

Bradbury et al., 2004 x

Daz & Telleria, 1994 x Doxa et al., 2010 x

Genghini et al., 2006 x

Peach et al., 2001 x

Asteraki et al., 1995 x Aviron et al., 2005 x Banks & Stark, 2004 x Batáry et al., 2007 x

Brittain et al., 2010 x

Clough et al., 2007b x Cole et al., 2005 x

Duelli & Obrist, 2003 x

Hendrickx et al., 2007 x Holzschuh et al., 2007 x Kitahara & Sei, 2001 x

Kremen et al., 2002 x Kremen et al., 2004 x Öckinger & Smith, 2007 x

Petit & Burel, 1998 x

Roschewitz et al., 2005b x Rundlöf et al., 2008 x Schmidt et al., 2005 x

Thies & Tscharntke, 1999 x Thorbek & Bilde, 2004 x Vollhardt et al., 2008 x Weibull et al., 2000 x

Pocock & Jennings, 2008 x x

Bates & Harris, 2009 x

Burel et al., 2004 x x

Figure 3 shows the frequencies of papers listed in Table 1, claiming different effects (positive, negative, no effect or mixed) of AI on biodiversity. There is no clear pattern in the results.

Fig. 3. Frequencies of papers claiming various types of effect of AI on biodiversity for the four taxa studied. G-test, significance 5%

Fig. 4. Frequencies of papers claiming various types of effect of landscape structure on biodiversity for the four taxa studied. G-test, significance 5%

Figure 3 shows the frequencies of papers listed in Table 1, claiming different effects (positive, negative, no effect or mixed) of AI on biodiversity. There is no clear pattern in the results.

Fig. 3. Frequencies of papers claiming various types of effect of AI on biodiversity for the

Fig. 4. Frequencies of papers claiming various types of effect of landscape structure on

biodiversity for the four taxa studied. G-test, significance 5%

four taxa studied. G-test, significance 5%

Figure 4 shows the frequencies of papers listed in Table 2, claiming different effects (positive, negative, no effect or mixed) of landscape structure on biodiversity. Similarly, there is no clear pattern in the results, except for the significantly larger number of papers claiming a positive effect of landscape structure on biodiversity of invertebrates, compared with the other groups of organisms studied.


Table 2. References to studies used in the meta-analysis dealing with the relationship between landscape structure and biodiversity of the four groups of organisms studied.

Biodiversity Drifts in Agricultural Landscapes 325

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Asteraki, E. J.; Hanks, C. B. & Clements, R. O. (1995). The influence of different types of

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Benton, T. G.; Vickery, J. A. & Wilson, J. D. (2003). Farmland biodiversity: is habitat

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