Effectiveness of agri-environmental management on pollinators is moderated more by ecological contrast than by landscape structure or land-use intensity
Marja, Riho ; Kleijn, David ; Tscharntke, Teja ; Klein, Alexandra Maria ; Frank, Thomas ; Batáry, Péter - \ 2019
Ecology Letters 22 (2019)9. - ISSN 1461-023X - p. 1493 - 1500.
Agri-environmental schemes - bees - biodiversity - butterflies - ecosystem services - flower strips - hoverflies - land-use intensity - meta-analysis
Agri-environment management (AEM) started in the 1980s in Europe to mitigate biodiversity decline, but the effectiveness of AEM has been questioned. We hypothesize that this is caused by a lack of a large enough ecological contrast between AEM and non-treated control sites. The effectiveness of AEM may be moderated by landscape structure and land-use intensity. Here, we examined the influence of local ecological contrast, landscape structure and regional land-use intensity on AEM effectiveness in a meta-analysis of 62 European pollinator studies. We found that ecological contrast was most important in determining the effectiveness of AEM, but landscape structure and regional land-use intensity played also a role. In conclusion, the most successful way to enhance AEM effectiveness for pollinators is to implement measures that result in a large ecological improvement at a local scale, which exhibit a strong contrast to conventional practices in simple landscapes of intensive land-use regions.
Effects on participation and biodiversity of reforming the implementation of agri-environmental schemes in the Netherlands
Groeneveld, A.N. ; Peerlings, J.H.M. ; Bakker, M.M. ; Polman, N.B.P. ; Heijman, W.J.M. - \ 2019
Ecological Complexity 40 (2019)B. - ISSN 1476-945X - 17 p.
Agri-environmental schemes - Biodiversity - Contracts - Mathematical programming
To prevent further biodiversity loss as a result of intensive agricultural practices, Agri-Environmental Schemes (AES) have been implemented on European farmland. Unfortunately these AES have not always been effective in terms of biodiversity and farmer participation. In an effort to improve the AES programme the Dutch government switched from an individual application system to a collective application system for AES payments in 2016. The goal of this paper is to analyse how the resilience of the land use system in terms of farmer participation in the AES and biodiversity is affected by the value farmers attach to biodiversity, and whether the shift from an individual to collective AES will affect the resilience of the land use system. We constructed a multi-objective mathematical programming model in which farmers maximise utility. Farmers are linked through their common effect on biodiversity. In the collective application system payments are only available when the biodiversity in the region is above a certain threshold. Simulation results show no difference in farmer participation and biodiversity between the individual application system and the collective application system when biodiversity weights are high. The land use system loses its resilience in terms farmer participation in the AES and biodiversity if we lower the biodiversity weights, this effect is stronger in the collective AES programme.
Landscape-scale forest cover increases the abundance of Drosophila suzukii and parasitoid wasps
Haro-Barchin, Eduardo ; Scheper, Jeroen ; Ganuza, Cristina ; Groot, G.A. de; Colombari, Fernanda ; Kats, Ruud van; Kleijn, David - \ 2018
Basic and Applied Ecology 31 (2018). - ISSN 1439-1791 - p. 33 - 43.
Agri-environmental schemes - Agroecosystems - Conservation biological control - Drosophila suzukii - Ecosystem services - Invasive species - Landscape complexity - Natural enemies - Parasitoid wasp - Semi-natural habitat
Agricultural landscapes rich in natural and semi-natural habitats promote biodiversity and important ecosystem services for crops such as pest control. However, semi-natural habitats may fail to deliver these services if agricultural pests are disconnected from the available pool of natural enemies, as may be the case with invasive species. This study aimed to provide insights into the relationship between landscape complexity and the abundance of the recently established invasive pest species Drosophila suzukii and a group of natural enemies (parasitoid wasps), which contain species that parasitize D. suzukii in native and invaded ecosystems. The importance of landscape complexity was examined at two spatial scales. At the field scale, the response to introduction of wildflower strips was analysed, while the relationship with forest cover was assessed at the landscape scale. Half of the surveys were done next to blueberry crops (Vaccinium corymbosum), the other half was done in landscapes without fruit crops to examine effects of D. suzukii host presence. As expected, the number of observed parasitoid wasps increased with amount of forest surrounding the blueberry fields, but the number of D. suzukii individuals likewise increased with forest cover. Establishment of wildflower strips did not significantly affect the abundance of D. suzukii or parasitoid wasps and insect phenology was similar in landscapes with and without blueberry crops. This suggests that D. suzukii is enhanced by landscape complexity and is largely unlinked from the species group that, in its native range, hosts key natural enemies. Although management practices that rely on enhancing natural enemies through habitat manipulations can contribute to the long-term stability of agroecosystems and to control agricultural pests, other control measures may still be necessary in the short term to counteract the benefits obtained by D. suzukii from natural habitats.