Beneficial Insects 198 agricultural intensification and the paucity of To determine whether native plantings on Insect ower visitors of planted native species within semi-natural habitats can also impact ecosystem arable farms support pollinator diversity the the arable landscape on the Canterbury Plains, service providers like insect pollinators current study, conducted over an entire summer (Morandin & Kremen 2013) and insect pest season, documented insect flower visitors on New Zealand regulators (Davidson et al. 2015; Fontaine et al. eight native tree species planted on three farms. 2006). This information is required to assess whether Franziska G. Schmidlin1,*, Jon J. Sullivan1, Mike H. Bowie1 and Brad G. Howlett2 With the worldwide decline of honey bee such plantings can assist in supporting a diversity populations, thought to be due to a combination of known arable crop pollinators. 1 Agriculture and Life Sciences Division, Lincoln University, PO Box 84, Lincoln 7647, New of habitat loss, agrochemicals, pathogens and Zealand climate change (Potts et al. 2010), the future METHODS 2 e New Zealand Institute for Plant & Food Research Limited (PFR), Private Bag 4704, regarding long-term crop-pollination service is Study system Christchurch Mail Centre, Christchurch 8140, New Zealand uncertain. It is risky to rely on a single species Three farms within 50 km of Rakaia, Canterbury * Corresponding author: [email protected] to pollinate crops and produce food (Klein et al. (43º 33’ 56’’ S, 171º 41’ 35’’ E, 7 m above sea level, 2007; Potts et al. 2010). Preserving landscapes 43º 53’ 39’’ S, 171º 50’ 46’’ E, 21 m, and 43º 53’ Abstract Almost all of the original native vegetation of Canterbury Plains has been replaced that support wild pollinator populations can 32’’ S, 172º 06’ 55’’ E, 172 m) were assessed. All with an arable landscape of managed exotic vegetation. A previous study planted small be regarded as an important, and prudent, three conventionally managed farms had native areas of native trees on arable farms in 2013 to enhance the abundance and diversity of insurance against potential failures in crops biodiverse plantings established in October 2013 beneficial insect crop pollinators. The aim of the current study was to assess insect flower pollinated predominantly by honey bee (and as part of a project funded by the Foundation for visitation at three sites in the fifth year after planting. Weekly standardised surveys of native bumble bee) populations. Native or semi-native Arable Research and the Sustainable Farming flower visitors were conducted between September 2017 and February 2018. A total of 2349 habitats within agricultural landscapes can Fund. All plantings are located in the vicinity of insects from 37 taxa were observed within three native plantings. Native bees (Lasioglossum increase wild bee populations (Jauker et al. 2009; crop fields. In 2017/2018, the adjacent crops were sordidum 20%) and the honey bee, Apis mellifera (19%), were the most common followed Lentini et al. 2012; Ponisio et al. 2016; Venturini seed crops of ryegrass Lolium perenne, mustard by the large hoverfly, Melangyna novaezelandiae (16%). The calliphorid flies, brown blowfly et al. 2017). This can support increased yields or Sinapis alba, red clover Trifolium pratense, and Calliphora stygia (8%) and blue blowfly Calliphora vicina (6%), were also well represented. yield consistency due to their complementarity flax Linum usitatissimum. Spacing between The most abundant insects visited four or more of the eight study plant species. Most (52%) with pollination services, for example through seedlings within the native plantings was 1.5 m of the flower visitors where natives. Many of these insects are known crop pollinators and it diversifying pollen transfer pathways (Garibaldi x 1.5 m throughout. The plantings were between is likely that they assist with crop pollination. et al. 2013), differing activity patterns under 300 m2 and 440 m2 and each consisted of 30–34 variable weather conditions (Howlett et al. species, including 26 species that were shared Keywords: agriculture, ecosystem services, pollination, native restoration, semi-natural 2013a) or seasonal activity (Howlett et al. 2016). across all sites. Eight of these shared species (see habitats, pollinator resource, crop pollination. In a recent analysis of 39 studies conducted in Table 1) were in bloom the season before and several countries across different continents, could, therefore, be tagged as study specimens. Rader et al. (2016) highlighted the significant The plantings were divided into six sections INTRODUCTION a wider range of crops and makes pollination role that non-bee insect pollinators play in global of even size, the midpoint of each section was Little is known about the importance of services more resilient to environmental change crop production. A diversity of insect species selected, then the closest tree to the midpoint perennially flowering woody vegetation in (Rader et al. 2013). The Canterbury Plains has (both bees and non-bees) visit the flowers of of the given species was chosen as marked supporting pollinating insects in New Zealand undergone significant agricultural intensification arable crops on the Canterbury Plains. These specimen. Each marked specimen was visited (Howlett et al 2013a) but such vegetation is since European settlement and is currently crops include pak choi Brassica rapa subsp. and, if in bloom (>20% open flowers per bush), known to support arthropod biodiversity dominated by livestock (particularly dairy) chinensis (Howlett et al. 2009), onion Allium observed weekly. One of the three farms had an (Fukuda et al. 2011). Intensively farmed, large- and arable farming (Dynes et al. 2010) notably cepa (Howlett et al. 2005), carrot Daucus carota apiary of 24 honey-bee colonies permanently scale arable landscapes areas are dominated by oilseed rape, other brassicas, clover, onions, subsp. sativus (Howlett et al. 2015), and radish placed at the edge of the native planting. single mass-flowering crops resulting in large carrots, radishes as well as wind-pollinated Raphanus ativus (Howlett et al. 2013b). Native fluctuations in floral resources during the season. grains and grasses. In such environments, the bees, bumblebees and several fly species have Flower visitor surveys Stavert et al. (2018) showed that agricultural high variation in floral resource availability for been verified as pollinators of pak choi (Howlett Between September 2017 and February 2018, intensification can increase exotic pollinators pollinators is thought to make it difficult for et al. 2011; Rader et al. 2009), onion (Howlett insect observation surveys were conducted (mainly Eristalis tenax) and compensate for large wild populations of pollinators to persist et al. 2017), carrot (Howlett 2012) and other weekly on the eight chosen native plant species. the loss of native pollinators. However, it is a (Dicks et al. 2015). Furthermore, the widespread vegetable seed fields in Canterbury (B. Howlett Two-minute surveys of flower visitors were biodiverse pollinator composition that supports use of pesticides and herbicides associated with unpublished data). conducted on the north and south side of each New Zealand Plant Protection 71: 198-206 (2018) https://doi.org/10.30843/nzpp.2018.71.170 Beneficial Insects 199 agricultural intensification and the paucity of To determine whether native plantings on Insect ower visitors of planted native species within semi-natural habitats can also impact ecosystem arable farms support pollinator diversity the the arable landscape on the Canterbury Plains, service providers like insect pollinators current study, conducted over an entire summer (Morandin & Kremen 2013) and insect pest season, documented insect flower visitors on New Zealand regulators (Davidson et al. 2015; Fontaine et al. eight native tree species planted on three farms. 2006). This information is required to assess whether Franziska G. Schmidlin1,*, Jon J. Sullivan1, Mike H. Bowie1 and Brad G. Howlett2 With the worldwide decline of honey bee such plantings can assist in supporting a diversity populations, thought to be due to a combination of known arable crop pollinators. 1 Agriculture and Life Sciences Division, Lincoln University, PO Box 84, Lincoln 7647, New of habitat loss, agrochemicals, pathogens and Zealand climate change (Potts et al. 2010), the future METHODS 2 e New Zealand Institute for Plant & Food Research Limited (PFR), Private Bag 4704, regarding long-term crop-pollination service is Study system Christchurch Mail Centre, Christchurch 8140, New Zealand uncertain. It is risky to rely on a single species Three farms within 50 km of Rakaia, Canterbury * Corresponding author: [email protected] to pollinate crops and produce food (Klein et al. (43º 33’ 56’’ S, 171º 41’ 35’’ E, 7 m above sea level, 2007; Potts et al. 2010). Preserving landscapes 43º 53’ 39’’ S, 171º 50’ 46’’ E, 21 m, and 43º 53’ Abstract Almost all of the original native vegetation of Canterbury Plains has been replaced that support wild pollinator populations can 32’’ S, 172º 06’ 55’’ E, 172 m) were assessed. All with an arable landscape of managed exotic vegetation. A previous study planted small be regarded as an important, and prudent, three conventionally managed farms had native areas of native trees on arable farms in 2013 to enhance the abundance and diversity of insurance against potential failures in crops biodiverse plantings established in