«The Economic and Social Aspects of Biodiversity Benefits and Costs of Biodiversity in Ireland REPORT PREPARED BY: CRAIG BULLOCK, OPTIMIZE CONSULTANTS ...»
A broadly sustainable agriculture of the kind envisaged under Rural Development Policy may still depend on external inputs and produce some waste, but to a lesser extent than the intensive alternative. These wastes should be of a quantity that could be assimilated by the environment.
Where nitrates or phosphates accumulate due to ecosystem services having been diminished or overwhelmed, the cost of “clean-up” or of “damage avoided” provides a measure of the benefits of a functioning biodiversity.
Amongst the problems which may arise when the ecosystem is damaged, is eutrophication.
Eutrophication of surface waters due to phosphates and, to a lesser extent nitrates, is amongst the principal problems facing the Irish environment. A reduction in human welfare arises from eutrophication due to phosphates. Human health risks also arise where excess nitrates are not removed from drinking water. This is rarely done in Ireland despite elevated levels in parts of the South and South-East (GSI 2000).
In the UK, the benefits of dealing with all sorts of diffuse pollution to water have been estimated to be worth £250 million per year (Environment Agency, 2002). A measure of the value of a functioning biodiversity is the avoidance of the external costs from this pollution. A whole-farm sustainable system that is more dependent on biodiversity provides a more continuous supply of nitrogen to plants and pasture with far less wastage than fertilizers. Indeed, leaching of these nitrates is typically 25-50% less on more sustainably managed or organic farms.
As the welfare element is considered elsewhere in this study, it is worth addressing the costs of physical removal of pollutants. For example, the annual cost of nitrate removal in the UK has been estimated at between £24 and £38 million (Redman, 1996, Cobb et al. 1999. Defra, 2004). Adjusting these estimates for the number of households in Ireland and the size the arable sector suggests that at least 2 million per year should be spent to avoid additional external costs. In fact, the Department of Agriculture is spending 39 million per year on the Nitrate Directive via the Farm Waste Management Scheme and those elements of REPS directed at nutrient management. There will be private costs too for some farmers, most especially pig and poultry producers who must comply with IPC licensing.
3.1.2 Ecosystem Services It is neither practicable nor entirely possible to deduce the relevance of all biological diversity in agricultural systems.This is because there are few studies in this area and global knowledge on the topic is very sparse. Most studies have focused on the adverse impact that agriculture is having on biodiversity, rather than the positive impact of biodiversity to agriculture. To illustrate the value of
biodiversity, we can focus three principal ecosystem services, namely:
1. Pollination2. Soil nutrient recycling,3. Pest predation and parasitism.
In recent years, ecological thinking has edged away from the concept of “keystone species” responsible for such ecosystem services. Instead, there has been a recognition of the functional inter-relationships that exist between all species together with renewed attention to the issue of whether ‘high biodiversity = stability’, therefore providing the insurance required for sustainability.
This, in turn, has led to increased interest in the concept of “redundancy”, i.e. where the same ecosystem services can be provided by more than one species (Bolger, 2000). Within this hypothesis, it is accepted that the extent to which a species is redundant may depend on environmental circumstances at any one time.
Nevertheless, there is some evidence to suggest that those species that are most important, and which exhibit low redundancy, are the same species that could be lost first to environmental change (Larsen et al. 2005). The concept of keystone species therefore still has some validity and is, at least, of illustrative value.
3.2 P O L L I NAT I ON 3.2.1 R E L E VA N T S P E C I E S A N D F U N C T I ON Amongst the most well-known services performed by a healthy biodiversity is pollination. Of pollinators, bees are the keystone species. As nectar is collected for both the colony and for the benefit of the individual bee, bees make more flower visits than any other insect. In Britain, honey bees (Apis mellifera) are presumed to be responsible for 80% of pollination, but bumble bees (Bombus terrestres) are the more efficient pollinators from a human perspective. Bumble bees are more active in our cool, wet climate. They are also the more willing to fly further from field boundaries into larger fields (Santorum & Breen, 2004). Their longer tongue length means they are able to pollinate a wider range of plants. While there are 13 true bee species in Ireland, the population of bumble bees, in particular, has unfortunately declined in recent decades. In parts of Britain and other European countries, this decline is now regarded as being quite serious.
3.2.2 R E L E VA N T S P E C I E S A N D F U N C T I ON
A gri c u l t u ra l c ro p s Bees have an important, and often critical, role in the pollination of many horticultural and fruit crops. Ireland’s agriculture also benefits from this pollination service, although our climate does mean that a lower proportion of agricultural output is represented by these crops than in most other European countries.
While Ireland may not be a big producer of fruit or horticultural crops, it does have a dependence on one crop whose association with pollination could easily be overlooked. Clover is very dependent on bees for pollination. Clover is a forage crop that fixes nitrogen from the air and so contributes both to animal weight and growth (Nolan & Grennan, 1998). Furthermore, clover is a substitute for nitrogen fertilizers on extensive and organic pastures. It could yet attain renewed importance given EU controls on artificial nitrogen fertilisers and expected trends towards extensification. Seeding depends on bees at a quantity of up to 15 colonies per hectare. Both honey and bumble bees can fertilize the agriculturally important white clover, but the latter’s readiness to travel longer distances makes them the more useful pollinator in larger fields. For red clover, the length of the flower means that only bumble bees can “trip” the flower.
Of other crops, Ireland may not be a big producer of fruit, but some pollinated crops are nevertheless locally important, including tomatoes, strawberries and smaller quantities of apples and berry crops such as blackcurrant. Organic production of each of these crops is becoming more common. Apples have a high dependence on pollination by bees and between 0.6 and 5 colonies per hectare are required. Blackcurrants are also highly dependent on both honey and bumble bees.
In the case of strawberries, pollination is of most value to increasing seed number. Bee pollination also contributes to improved quality and fruit size.
Bee pollination is less important for tomatoes as pollination is achieved by wind, aided by the physical shaking of the flowers. Bees do, however, improve the efficiency of this process by vibrating the flower. Bee pollination is also of only modest importance to oilseed rape. However, it is reported to improve the timeliness and evenness of crop maturity (Williams et al, 1987).
Furthermore, oilseed rape could yet become a very important crop in the future for biofuel.
Domesticated bees Of course, given past trends towards agricultural intensification, it is no surprise to find that bees too have been domesticated for the purpose of pollination. The services of wild bees have in many cases been replaced by the provision of hives. In fact, this is a long established practice in orchards and the mutually beneficial relationship between beekeepers and farmers has been the subject of key economics papers (Coase, 1965). Due to natural population fluctuations, together with the decline in numbers of wild bees, this service has now become artificially available in glasshouses and polytunnels. Beginning with honey bees in the eighties, domestication of the more useful bumble bee has now become common. Bumble bees are less manageable than honey bees, although the latter are notoriously unreliable in tunnels, often choosing to escape once vents are opened.
W i l d p l an t s an d ga rd e n s Despite some domestication, wild bees will continue to be essential to the success of clover and of other crops grown on larger fields. Furthermore, as well as agricultural crops, bees are of obvious value to many wild plants. As can be expected, many of these plants provide food or habitat for other species, including those that are valuable, in some way or another, to ourselves. Some of these wild plants could be considered weeds by farmers but, in fact, provide nectar for the bees outside of those times when their services are required by commercial crops.
Naturally, bees also have an important role in gardens, including those where vegetables and fruit are grown. In turn, this makes bees essential to the output of the valuable garden centre trade.
International estimates In the US, Robinson et al. (1989) have estimated that 31% of the value of US agricultural production is dependent on bees. This contribution is conservatively valued at over 9 billion per annum.
Morse and Calderone (2000) are less cautious and estimate pollination to be worth up to 14.6 billion. Similarly, an estimate for Canada has been placed at C$1.2 billion per annum (Winston et al, 1984).
In the EU the contribution of wild bees has been estimated at 5 billion per annum, and 4.25 billion for domesticated bees (Corbett et al, 1991). 2 For the UK, Carreck and Williams (1998) apply a weighting system for different crops. Using this method, they estimate a value of £172 million for outdoor crops and £30 million for those under cover. On the same basis, they estimate the average value of each honey bee colony to be £12.
T h e E c o n o m i c an d S o c i a l Va l u e t o I re l an d Bees provide a service to production that can be estimated directly in economic terms. An approximate estimate of the current pollination benefit of bees in Ireland would be 85 million per annum. This figure would represent a reduction on previous years given the increasing use of polytunnels and domesticated bees for much fruit and tomato production, in part because of the declining bee population. Domestication of bees has become far more widespread since the early nineties and provides something of a guarantee against natural fluctuations in bee populations despite the greater efficiency with which wild bees fertilise plants. As tunnels provide effective climate control, only rather small areas of outdoor strawberry production remain.
Gross values before subsidies. 2005 values (CSO).
Original estimates were in ECUS. All figures would need to be adjusted upwards for inflation.
There is no specific information on the marginal value of bees. However, it would not be unreasonable to attribute a portion of the additional input cost represented by the provision of domesticated colonies to the decline in the wild bee population as an indication of the benefit of this ecosystem service. Moreover, the relative value of wild bees is increasing as the population declines and farm systems change. Demand for biofuels is expected to bring about a doubling of the area of oilseed rape across the EU (Doyle, 2007). Bees are also important to the crosspollination of an increasing production of hybrid crops, including fruits.
Furthermore, the role of bees in the pollination of clover may mean that this ecosystem service becomes yet more important given that clover is a natural substitute for polluting nitrogen fertilizer.
Were clover to play a greater role beef and dairy production given trends to more rigorous environmental criteria including nitrate management, the biodiversity contribution of pollination could be worth far more in the future. Currently, grassland farmers account for two thirds of the 250 million spent annually by Irish farmers on nitrogen fertiliser (CSO, 2006). In the UK the external costs of excess nitrogen application, in terms of human health and acidification, have been estimated at between £0.5 and £1 billion per year (Hartridge and Pearce, 2001).
In that bees are also important for parks and gardens, they also perform an important economic role in helping to support Ireland’s 380 garden centres and an amenity/plant industry that is worth around 300 million of which the farmgate value of nursery stock is 50 million. Gardens have a very important social role too, of course, and one that certainly has economic, social and health benefits. The bees contribution is, though, of more value to vegetables than for blooms.
Of ultimately more importance, is the equivalent economic and social benefits that are associated with countryside recreation. Bees ensure the survival of many wild plant species and are vital as food or habitat for Irish wildlife as well as being a fundamental element of the familiar rural landscape that is valued by so many people. The size of this public good is unknown, but is obviously considerable. According to Corbet et al. (1991), 27% of the 321 bee-pollinated wild plant species are endangered.
3.2.4 T H R E AT S Pollination is an ecosystem service that is under threat from the falling bee population. As well as falling absolute numbers, there has been a decline in the diversity of species recorded on farms.
Bumble bees, in particular, have declined significantly. Already, in Britain, field beans often have to be pollinated by hand because of the shortage of bees. In Ireland, crops grown under cover are already dependent on domesticated bees. Orchard owners are taking pro-active steps to ensure pollination given both the decline in wild bees and falling interest in beekeeping.