Protecting our Pollinators
Declining bee populations, due to habitat loss and climate change, is an area of real concern for Irish agriculture and our wider rural landscape. Bees provide service to our crops and wild plants in terms of pollination, so understanding ways to ensure their health and survival is crucial.
The research project SUSPOLL, which is funded by Science Foundation Ireland, examines the impacts of both climate change and pesticide use on pollination. Dr Dara Stanley at the UCD School of Agriculture and Food Science explains: “SUSPOLL looks at these threats and examines the implications for bees and specifically how well bees can pollinate crops. Pesticides are very important and integral to the way we produce food currently, but we need to use them as safely as we can. And, while our pesticides are risk assessed in terms of lethal impacts on bees, they can also affect bees in a sublethal way, which can in turn affect behaviour and reproduction and have an impact on foraging and their ability to collect pollen.”
Species
Traditionally, risk assessment has focussed on the honeybee; Dara says that a focus on other species such as bumblebees and solitary bees are also important. “From the climate change side, the first thing we need to do is have a better understanding of how bees are responding to weather conditions. There are nearly 100 species of bees in Ireland and there can be four seasons in one day, so this is key. Are all species responding in the same way in terms of changing climatic conditions or are there going to be winners and losers? Honeybees and bumblebees, for example, respond differently: bumblebees are more resilient and will fly in wetter conditions. Therefore, having a diversity of bee species in the landscape providing pollination is going to be helpful in relation to climate change.”
Pesticide usage
Alongside the work that the SUSPOLL project has completed over the past four years, the PROTECTS project has released its findings this year in relation to pesticide usage in Ireland and how we can use pesticides more sustainably. “The project looked at how we can understand pesticide use and impacts on the environment more so that we can give the best advice and policy recommendations around sustainable pesticide use. Herbicides and fungicides are what we use most widely in Ireland, which reflects our grass-based farming model and in our damp climate fungal issues are a bigger issue for crops than elsewhere. With the reduction in available insecticides on the market at the moment, there is a move towards the use of older chemistries for insect pest control and the most widely used insecticide in Ireland is now the pyrethroid, lamba-cyhalothrin.”
Consistent data
Dara notes that, while we are encouraged to report pesticide usage in the EU, the method of reporting differs from country to country with different formats, different timeframes and different measurements across the board. “We found that it is almost impossible to compare different countries within the EU regarding pesticide usage, or even to review usage across the EU as a whole, as the metrics were so different between countries. If we want to be able to use this data effectively and track and monitor our pesticide usage in terms of meeting reduction targets, then we need to have a standardised way of monitoring across the EU.”
Residue
Once the work had been done on identifying pesticide usage in Ireland, the next step was to discover what implications there were for bees and to investigate residue build-up in soils. “In terms of oilseed rape and bramble, we found residue of herbicides, fungicides and insecticides in both the nectar and the pollen of both. We also found some residues of neonicotinoid insecticides that haven’t been used in several years – which have been banned for almost a decade – but they are still persisting in the environment. There was evidence of pesticides in soils from fields that have never been sprayed, as well, so there may be possible leeching or drift. Overall, it shows that residues of pesticides can linger over time and move across locations, and while the levels are below what would be toxic in terms of lethal toxicity, there could still be things to consider in terms of non-lethal toxicity for bees.”
Recommendations for use
Recommendations in terms of pesticides usage was another area of interest in the PROTECTS project. As Dara notes: “The fact is we use pesticides and will need to continue to use them in the foreseeable future. But we still need to review how we can use them in ways that will minimise any environmental effects, and understand the recommendations for usage to protect our bees. Currently, at the back of many labels for example, there are recommended guidelines about how to use pesticides in ways that will reduce risks for bees such as spraying in the morning and evening. We wanted to review the evidence for these guidelines. As it turns out, there is very little science behind some of this advice regarding mitigation measures. We just don’t know how effective they are and if we are giving advice to use pesticides in a certain way we need to know if that advice is sound. So, we did a study into the time of day that is optimal for spraying to reduce contact with pollinators, looking at pollinator activity for oilseed rape from sunrise to sunset. The honeybee was less active in early morning and late evening and there was a huge increase in activity in the middle of the day. However, the bumblebees had a much longer stretch in activity across the day while hoverflies had no peak and were active throughout all hours of daylight. "So the current advice is certainly better for the honeybee but may not be quite as effective for other species. In addition, we also know that pesticide residues will still linger so how effective spraying at certain times of the day is is really unknown. Much more work needs to be done here so that we can provide effective guidance. On a positive note, we did find that people take guidelines into account and will follow instruction when it comes to pesticides. Irish farmers are very cognisant of guidelines when it comes to impacts on the environment.”