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Agri-environment schemes are programmes where landholders enter into voluntary agreements (typically with governments) to manage agricultural land for environmental protection and nature conservation objectives. Previous work at local scale has shown that these features can provide additional floral and nesting resources to support wild pollinators, which may indirectly increase floral visitation to nearby crops. However, the effect of entire schemes on this important ecosystem service has never previously been studied at national scale. Focusing on four wild pollinator guilds (ground-nesting bumblebees, tree-nesting bumblebees, ground-nesting solitary bees, and cavity-nesting solitary bees), we used a state-of-the-art, process-based spatial model to examine the relationship between participation in agri-environment schemes across England during 2016 and the predicted abundances of these guilds and their visitation rates to four pollinator dependent crops (oilseed rape, field beans, orchard fruit and strawberries). Our modelling predicts that significant increases in national populations of ground-nesting bumblebees and ground-nesting solitary bees have occurred in response to the schemes. Lack of significant population increases for other guilds likely reflects specialist nesting resource requirements not well-catered for in schemes. We do not predict statistically significant increases in visitation to pollinator-dependent crops at national level as a result of scheme interventions but do predict some localised areas of significant increase in bumblebee visitation to crops flowering in late spring. Lack of any significant change in visitation to crops which flower outside this season is likely due to a combination of low provision of nesting resource relative to floral resource by scheme interventions and low overall participation in more intensively farmed landscapes. We recommend future schemes place greater importance on nesting resource provision alongside floral resource provision, better cater for the needs of specialised species and promote more contiguous patches of semi-natural habitat to better support solitary bee visitation.

Agri-environment schemes are programmes where landholders enter into voluntary agreements (typically with governments) to manage agricultural land for environmental protection and nature conservation objectives. Previous work at local scale has shown that these features can provide additional floral and nesting resources to support wild pollinators, which may indirectly increase floral visitation to nearby crops. However, the effect of entire schemes on this important ecosystem service has never previously been studied at national scale. Focusing on four wild pollinator guilds (ground-nesting bumblebees, tree-nesting bumblebees, ground-nesting solitary bees, and cavity-nesting solitary bees), we used a state-of-the-art, process-based spatial model to examine the relationship between participation in agri-environment schemes across England during 2016 and the predicted abundances of these guilds and their visitation rates to four pollinator dependent crops (oilseed rape, field beans, orchard fruit and strawberries). Our modelling predicts that significant increases in national populations of ground-nesting bumblebees and ground-nesting solitary bees have occurred in response to the schemes. Lack of significant population increases for other guilds likely reflects specialist nesting resource requirements not wellcatered for in schemes. We do not predict statistically significant increases in visitation to pollinator-dependent crops at national level as a result of scheme interventions but do predict some localised areas of significant increase in bumblebee visitation to crops flowering in late spring. Lack of any significant change in visitation to crops which flower outside this season is likely due to a combination of low provision of nesting resource relative to floral resource by scheme interventions and low overall participation in more intensively farmed landscapes. We recommend future schemes place greater importance on nesting resource provision alongside floral resource provision, better cater for the ...

Background and aims – Agricultural intensification and loss of farmland heterogeneity have contributed to population declines of wild bees and other pollinators, which may have caused subsequent declines in insect-pollinated wild plants. Material and methods – Using data from 37 studies on 22 pollinator-dependent wild plant species across Europe, we investigated whether flower visitation and seed set of insect-pollinated plants decline with an increasing proportion of arable land within 1 km. Key results – Seed set increased with increasing flower visitation by bees, most of which were wild bees, but not with increasing flower visitation by other insects. Increasing proportion of arable land had a strongly variable effect on seed set and flower visitation by bees across studies. Conclusion – Factors such as landscape configuration, local habitat quality, and temporally changing resource availability (e.g. due to mass-flowering crops or honey bee hives) could have modified the effect of arable land on pollination. While our results highlight that the persistence of wild bees is crucial to maintain plant diversity, we also show that pollen limitation due to declining bee populations in homogenized agricultural landscapes is not a universal driver causing parallel losses of bees and insect-pollinated plants. ; EU FP5 QLRT-2001-01495 ; Swiss Federal Office for Science and Technology (01·0524-2) ; FORMAS ; Estonian Ministry of Education and Research IUT (IUT20-33) ; Internal Grant Agency of the Faculty of Environmental Sciences Czech University of Life Sciences Prague 42900/1312/3166 ; MC-CIG BeeFun project: PCIG14-GA-2013-631653 ; DAFM ; IRC ; Formas (2018-01466) ; German Ministry of Research and Education (FKZ: 01LC1104A) ; NKFIH project (FK123813) ; NKFIH (KKP 133839) ; European Union in the 7th Framework Programme (grant 244090), ; MTA Bolyai Fellow ; Peer reviewed

Background and aims: Agricultural intensification and loss of farmland heterogeneity have contributed to population declines of wild bees and other pollinators, which may have caused subsequent declines in insect-pollinated wild plants. Material and methods: Using data from 37 studies on 22 pollinator-dependent wild plant species across Europe, we investigated whether flower visitation and seed set of insect-pollinated plants decline with an increasing proportion of arable land within 1 km. Key results: Seed set increased with increasing flower visitation by bees, most of which were wild bees, but not with increasing flower visitation by other insects. Increasing proportion of arable land had a strongly variable effect on seed set and flower visitation by bees across studies. Conclusion:Factors such as landscape configuration, local habitat quality, and temporally changing resource availability (e.g. due to mass-flowering crops or honey bee hives) could have modified the effect of arable land on pollination. While our results highlight that the persistence of wild bees is crucial to maintain plant diversity, we also show that pollen limitation due to declining bee populations in homogenized agricultural landscapes is not a universal driver causing parallel losses of bees and insect-pollinated plants. ; The original idea was conceived aspart of the project 'STEP - Status and trends of Europeanpollinators' funded by the European Union in the 7thFramework Programme (grant 244090), which fundedRB, ISD, HGS, SP, MR, LH, JME, and KS. JE and PCwere funded by MULTAGRI/FORMAS. MA was fundedby the EU FP5 project 'Evaluating current European agri-environment schemes to quantify and improve natureconservation efforts in agricultural landscapes' (EASY;QLRT-2001-01495) and the Swiss Federal Office for Scienceand Technology (01·0524-2). AJ and EÖ were funded byFORMAS. TTe and VS were supported by institutionalresearch funding IUT (IUT20-33) of the Estonian Ministryof Education and Research, and TTe also received funding(grant no. 42900/1312/3166) from the Internal Grant Agencyof the Faculty of Environmental Sciences, Czech Universityof Life Sciences Prague. IB was funded by MC-CIG BeeFunproject: PCIG14-GA-2013-631653 and thanks the DoñanaNP staff members for granting access to the Park and CurroMolina for conducting the field work. JS, EFP, and SM werefunded by DAFM and IRC. LH was funded by a grant fromFormas to HGS and by a mobility grant from Formas (2018-01466). ALH was funded by the FarmLand project supportedby the German Ministry of Research and Education (FKZ:01LC1104A). AKH was supported by the NKFIH project 348Pl. Ecol. Evol.154 (3), 2021(FK123813) and was a Bolyai Fellow of MTA. PB wassupported by the NKFIH (KKP 133839).