Developing techniques for enhancing broad bee diversity in farmland

This project will look at the impact of sowing different types of wild flower seeds on the edges of farm fields on encouraging a wider variety of bees. It builds on a previous Research Council studentship which found that many types of bees prefer the hedgerow plants such as brambles, which are not encouraged by farmers.
Recent Research Council funded research at Sussex carried out on farms in South England has shown that current flower strips sown under agri-environment prescriptions boost populations of some common bumblebee species but provide negligible benefit for the many other bee species that live in farmland.

The three strands of this new project are:-

a) The Student will survey the 18 farms studied by a previous Research Council funded project, quantify the distribution & abundance of flowers of the target plant species and relate this to the management history of the various farm features. The aim here is to establish which management practices have resulted in high abundance of the desired flowers.

b) Experimental manipulation of hedgerow cutting regimes will be tested to establish which regimes best favour the target flowers. Hedgerow stewardship options already exist (e.g. BE3) and it may be that these are satisfactory provided that the correct woody species are present. In this case, encouraging planting of target species such as Cornus during gap filling & planting of new hedges may be sufficient.

c) Trialling seed mixes of the target ruderal species sown in flower strips (versus control strips, those sown with a conventional pollinator mix, & a hybrid mix aiming to benefit all bee species). Seed for most of the target ruderal species is readily available and establishment is straight-forward. However, encroachment into the neighbouring crop may be an issue and will be closely monitored and means to manage this tested in collaboration with the farmers.

In (b) and (c) the full range of pollinators visiting experimental plots will be surveyed (not just bees), to provide a holistic measure of the benefits of different managements for beneficial insects. The Student may also examine pollination deposition and deficit in a subset of the above plant species to determine whether experimental manipulations in (b) and (c) results in improvements in pollination of plants typically pollinated primarily by solitary bees.