Dr. Rogier Schulte:

These are good questions also.

Let me start with the cost-effectiveness and then I will come to the pearl mussel as an example. We conducted a study in the Lough Melvin area. Lough Melvin is one of these pristine water bodies. It was a North-South collaboration because it is a cross-Border lake. We looked at approximately 20 different options to reduce loss of phosphorus, from the land to the water. Phosphorus was the biggest threat to that pristine water quality. We found that, in theory, many of the measures would be effective in reducing phosphorus flow, from the land to the water, but the difference in cost was significant. To give two extreme examples, one measure proposed in the scientific literature is to stop access of animals to the water bodies. In the Lough Melvin area, the challenge is that there is water everywhere and the stocking rate is low, and one would need miles of fencing to keep each cow out of the water. If one considers the cost-effectiveness of stopping that one cow from standing in the water, it is an expensive option. Another measure we looked at was soil testing for phosphorus and customising the fertiliser management accordingly, which came out as a cheap option.

It is worth noting though that such difference in cost-effectiveness is catchment-specific. The reason fencing was so expensive on Lough Melvin is miles per cow. If one goes to a different catchment with well-drained soils, few rivers or streams, and a high stocking density, that equation changes completely. Also, if one looks at other risks, such as transfer of pathogens, then in that equation for keeping the cows out of the water one comes up with a different figure for cost-effectiveness, but it can differ by orders of magnitude. In fact, in the Lough Melvin scenario, and if the objective is to reduce phosphorus, then the fencing option turned out to be 100 times more expensive than soil testing if one compares kilo for kilo of phosphorus lost to the water. It is a real issue.

On the additional actions for the pristine water quality, the pearl mussel is a peculiar case study. A map in the presentation shows the catchments where the pearl mussel is found. It is a slow-growing animal. It is particularly the young pearl mussels, the juveniles, that are sensitive to both nutrient loss and sediment loss. Basically, if there are excess nutrients and excess sediment, they get buried and sufficate at the bottom of the stream. Once they grow to adulthood, they can live for a long time. They can live for over 100 years. The challenge is that in all of these blue catchments shown the slide the pearl mussel has been found but in some of these catchments we - by which I mean the National Parks and Wildlife Service, as it, not Teagasc, conducts the surveys - find only adults remaining. These adults are almost relics of when those waters were pristine, whereas in some of the western catchments there are still viable populations that have a chance of breeding and continuing themselves.

This leads us to a peculiar challenge. Under the habitats directive, we are obliged to protect this species but nobody knows whether it is technically possible for these old pearl mussels to start breeding again in some of the more intensively used catchments - hence our hesitation in making straight statements on what should be done. To the best of our knowledge, the National Parks and Wildlife Service has now also prioritised the catchments accordingly. It has put the highest priority on those catchments where the pearl mussels are still breeding and there is a chance of success. That brings me back to cost-effectiveness.

We are better off putting money into small catchments, where there is a chance of success, rather than spreading it over a large area where it may be difficult.

The first point we are trying to make is that some of the soil functions are tradeable between areas while others are not. Water quality is a soil function that is not tradeable because we require good groundwater conditions for drinking wherever we are. We cannot increase the pressure on water quality in one area at the expense of another area and vice versa. Carbon sequestration is the other side of the extreme. Technically, from the point of view of the atmosphere or from a global warming point of view, it is irrelevant what catchment, what area or even what country the carbon comes from. The reason we mention it in the paper is that at regional and national level it may not be the most prudent approach to expect every farmer to put all his energy into soil everywhere for the purpose of carbon sequestration because not all soils are suitable for further carbon sequestration. We may get more benefits from trading between catchments or regions where people target carbon sequestration and food production. That is an area we are currently conducting research on so we do not have the final word on it. It will be a number of years before we are finished. We are doing a number of scenario analysis projects.

Deputy Pringle is correct to point out the potential difficulties at international level. Scientifically, the concept holds internationally and, just like in the energy market which we were discussing before we came in, there is a move for southern Europe to produce solar energy in summer and northern Europe to produce wind turbines in the winter. This can then be traded and it makes the most of our resources. The same could apply to carbon sequestration if we identify areas that are good at the carbon sequestration and areas that are good at producing grain It is a very difficult area will prove difficult even within the EU. Had do we value it and how do we incentivise countries? Will we export our problems to developing countries? That is a question mark that can be already placed over the reducing emissions from deforestation and forest degradation, REDD, vehicle under the UNFCCC where, as a country, we can invest in credits in developing countries. There is merit in it and it is a win-win scenario but there is a valid question as to whether we are exporting our problems. As a scientist, I am reluctant to say as there is no scientific answer to it. It is a matter of values.