The influence of landscape context and farming practices on parasitism of cereal aphids

By Indra Roschewitz, Melanie Hücker, T. Tscharntke, Carsten Thies. 2005

216 citations recorded by the source corpus.

Abstract Agri-environmental schemes in Europe aim to support biodiversity and ecological functions in agroecosystems, which are related to both farming practices and landscape context. Here, we analysed the relative importance of farming practices and landscape context on an important ecosystem service, the naturally occurring biological pest control. In a 3-years study, we investigated cereal aphids and their mortality due to parasitism in 24 paired winter wheat fields (i.e., one organic and one conventional field close to each other). The field pairs were located in 12 landscapes differing in landscape complexity, simple landscapes with high percentage of arable land (∼80%), and complex landscapes with lower percentage of arable land (∼50%) and high proportions of semi-natural habitats. Arable land (%) was used as simple predictor of landscape complexity, as it was closely related with other landscape metrics like habitat-type diversity. Aphid population densities varied considerably between the 3 years and the 12 different landscapes. Organic farming was related to lower abundance of cereal aphids at the time of wheat flowering, but not to higher parasitism. At wheat ripening, complex landscapes were related to higher parasitism than simple landscapes, presumably due to more overwintering sites, alternative hosts and nectar sources for parasitoids. However, aphid population densities were also higher in complex landscapes, presumably due to the high availability of winter hosts for these host-alternating species. In a geographical scale analysis, we tested the relative importance of landscape complexity at 5 spatial scales (1–3 km radius around the study sites). Parasitoids responded to landscape complexity at spatial scales of 1–2 km, whereas aphid densities responded to landscape complexity at all spatial scales, indicating a trophic level-specific perception of the surrounding landscape. We conclude that complex landscapes with low percentage of arable land appeared to enhance parasitism, but also the host-alternating aphids, so overall effects of landscape complexity on cereal aphid control appear to be ambivalent.

Subfields: Ecology, Evolution, Behavior and Systematics, Insect Science, Plant Science

View Paper: https://www.semanticscholar.org/paper/48c48cf5556903fb75013fab7dbacc7b9e35935e

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Citations in the corpus

Landscape effects on the complex of Bactrocera oleae parasitoids and implications for conservation biological control (2009, background): “In order to better design agri-environmental measures, there is an urgent need to discriminate between the differential effects of management schemes and landscape structure on associated agrobiodiversity (Burel et al. 1998; Roschewitz et al. 2005).”
Assessing a farm's sustainability: insights from resilience thinking (2010, background): “…can be exemplified by the influence of agricultural policies (e.g. quotas or direct payments) on the economic framework and thus on the relative profitability of crops and of production methods, thereby influencing the choices of arable farmers and thus the agro-ecosystem (Roschewitz et al., 2005).”
Does landscape composition affect pest abundance and their control by natural enemies? A review (2013, background): “…were related to higher proportion of horticultural fields in he Netherlands (2 Bianchi et al., 2005) and lower cereal aphids arasitism to larger areas used as arable fields, although the correation changed during the season (Roschewitz et al., 2005; 19 Thies t al., 2005; Vollhardt et al., 2008).”
Biological Control of Insect Pests in Agroecosystems: Effects of Crop Management, Farming Systems, and Seminatural Habitats at the Landscape Scale: A Review (2010, background): “This hypothesis has been originally formulated and confirmed in a study comparing farming systems on arable weed diversity in different landscape types (Roschewitz et al., 2005a; Tscharntke et al., 2005).”
A meta-analysis of crop pest and natural enemy response to landscape complexity. (2011, background): “Furthermore, increased parasitism or predation can be offset by greater pest colonisation in complex landscapes, resulting in no net change in pest populations over a landscape gradient (Roschewitz et al. 2005; Thies et al. 2005).”
Organic versus conventional arable farming systems: Functional grouping helps understand staphylinid response (2007, result): “A study conducted in one of the regions included in the present work (Roschewitz et al., 2005) showed that aphid densities were indeed significantly higher in conventional than in organic fields, which supports this explanation.”
Sustainable pest regulation in agricultural landscapes: a review on landscape composition, biodiversity and natural pest control (2006, background): “Roschewitz et al. (2005) found higher densities of wheat aphids in complex landscapes as compared to simple landscapes because of increased aphid establishment.”