Does conservation on farmland contribute to halting the biodiversity decline?: Online Appendix 1.Notes on the type of conservation initiatives considered in this review and the impact of varying definitions of land-use intensity and landscape structure on the outcome of studies evaluating the effect of conservation initiatives on farmland.
David Kleijn, Maj Rundlöf, Jeroen Scheper, Henrik G. Smith, Teja Tscharntke.
Type of conservation initiatives considered
Although the primary objective of some of the examined conservation initiatives is not always biodiversity conservation (e.g. set-aside, organic farming, game cover strips) they have in common that they relax the intensity of land-use on farms or (parts of) agricultural fields and have, at times, proven to be beneficial to biodiversity. They are therefore included when we refer to conservation initiatives on farmland.
Landscape structure, land-use intensity, definitions and outcome of evaluation studies
Agricultural intensification generally results in a simplification of the agricultural landscape [A1.1,A1.2] and to some extent land-use intensity and landscape structure will be correlated. This relationship is, however, by no means robust and further depends on how and at what spatial scale land-use intensity or landscape structure is being measured [A1.3]. For example, Central European grasslands such as pusztas are characterized by large fields consisting of only a few habitat types. If habitat diversity is used as an indicator of landscape complexity [A1.4] these landscapes qualify as simple. These species-rich agricultural fields generally receive little or no fertilizers or pesticides [A1.5]. Management is therefore similar to that in many north-western European nature reserves which are generally considered to be semi-natural habitats. If the percentage of semi-natural habitats is used as an indicator of landscape complexity [A1.6], pusztas qualify as being quite complex. The many different ways of measuring both land-use intensity and landscape structure offer another explanation for the contrasting results of different studies examining the effects of conservation initiatives on farmland.
References
A1.1Benton, T.G. et al.(2003) Farmland biodiversity: is habitat heterogeneity the key? Trends Ecol. Evol. 18, 182-188
A1.2 Robinson, R.A. and Sutherland, W.J. (2002) Post-war changes in arable farming and biodiversity in Great Britain. J. Appl. Ecol. 39, 157-176
A1.3 Roschewitz, I. et al.(2005) Are landscape complexity and farm specialisation related to land-use intensity of annual crop fields? Agric. Ecosyst. Environ. 105, 87-99
A1.4 Chiron, F. et al.(2010) Effects of non-cropped landscape diversity on spatial dynamics of farmland birds in intensive farming systems. Biol. Conserv.143, 2609-2616
A1.5 Batáry,P.et al.(2010a) Comparing bee and insect-pollinated plant communities in intensively and extensively managed grasslands in Hungary, Netherlands and Switzerland. Agric. Ecosyst. Environ. 136, 35–39
A1.6 Tscharntke, T. et al.(2002). Contribution of small habitat fragments to conservation of insect communities of grassland-cropland landscapes. Ecol. Appl. 12, 354–363