«The Economic and Social Aspects of Biodiversity Benefits and Costs of Biodiversity in Ireland REPORT PREPARED BY: CRAIG BULLOCK, OPTIMIZE CONSULTANTS ...»
The ability of water to accept pollutants is itself an economic benefit, albeit one with social costs and one that operates most successfully where a functioning ecosystem survives to break down these pollutants. However, clean water has a more fundamental value. Much water is used for drinking and for domestic, agricultural or industrial purposes. For these services, a high level of source water quality is obviously desirable. Where this is not available, water can, of course, be purified, albeit at rising expense depending on the level of purification required. High quality water is most essential for the harvesting of fish. Here there is a strong relationship between water quality and fish catch. Angling, as a purely recreational activity, is relevant here too, as was, until just recently, commercial wild salmon harvesting. Indeed, all water-based recreation depends, to one extent or another, on the availability of high quality water.
( 1 ) S u s t ai n ab i l i t y an d E x t e r n a l C o s t s Consciously, or unconsciously, countries seeking rapid economic development often get by with greatly diminished water quality. China is one current example. However, doing so involves social costs. Ultimately, there is a strong relationship between water quality and quality of life. The free access nature of water means that it provides a ready means for the disposal of pollutants. Doing so, can mean that costs are passed downstream to other activities that need to
water and to any business or individual whose health or livelihood depends on clean water. Typically, the external cost to others exceeds the private benefits to the polluter, most certainly over time.
However, policing pollution is difficult, particularly where the polluters are responsible for many jobs or have political influence. Industrial polluters are, though, easy to identify. Once the economic case is accepted, end-of-pipe treatment typically provides an initial solution. Management is more difficult where the pollution is diffuse as is the case with much pollution from agriculture or scattered rural residential development.
Once pollution management is effective, it is possible to clean up rivers and lakes. Rivers such as the Thames or Liffey are substantially cleaner than they were in the past. However, restoration takes time and can involve considerable cost. Keystone species of a formerly complex aquatic ecosystem may have been lost. Lakes also act as depositories of pollutants. Even though the latest EPA data indicates some slight improvement in lake quality over the past five years, many important aquatic species and fish might never recover their former populations.
UN Living Planet Index
The Living Planet Index, created by the World Wide Fund for Nature and the UNEP-World Conservation Monitoring Centre, provides a measure of the trends in more than 3,000 populations of 1,145 vertebrate species around the world. The 2004 freshwater species population index took into account trend data for 269 temperate and 54 tropical freshwater species populations, 93 of which were fish, 67 amphibians, 16 reptiles, 136 birds, and 11 mammals. The index showed that freshwater populations have declined consistently and at a faster rate than the other species groups assessed, with an average decline of 50% between 1970 and 2000. Over the same period, marine fauna decreased by 30%. Overall, the trend is one of continuing decline in each ecosystem over the 30-year period.
Much of this decline has been the result of human impact, including the diversion of freshwater from estuaries (e.g. by river and lake abstraction schemes), which affects the delivery of water and sediment to nursery areas and floodplains. Furthermore, the intensification of agriculture and the release of poorly treated or untreated wastewater, has resulted in a substantial increase in nutrients entering the aquatic environment.
6.2 R E L E VA N T S P E C I E S A N D F U N C T I ONGood water quality is a two-way process. Numerous species are involved in cleaning water. These can be classified according to feeding groups and include vegetation shredders such as water lice and crayfish (Gammanus sp.), collectors/filterers such as blackfly and mayfly, larvae grazers such as snails and beetles, and bottom feeding detritivores (Cummins & Klug, 1979, Ostroumov, 2002). A good deal of interaction occurs between these species. For example, symbiotic relationships may exist between bivalves and fish, while crayfish and insect larvae also form a food source for fish. Otters and birds are next in the food chain.
Pollution from phosphates and nitrates has the effect of raising the nutrient load in rivers and lakes.
This encourages an increase in algae which is an important food source for the aquatic grazers or zooplankton whose numbers increase in response. By controlling the algae, these species perform an ecosystem service which is especially important for rivers at risk of falling into the slightly and moderately polluted EPA categories 3 and 4. However, once this eutrophication rises above a certain threshold, algal growth proliferates choking off the oxygen supply to other species.
As many species have evolved under circumstances of low nutrient status, even low levels of pollution can quickly have a destabilising impact. The mayfly is one familiar example of a species that depends on high quality water and is of obvious importance to the diet of many fish. At the other end of the scale in terms of longevity is the freshwater pearl mussel which can survive for 100 years and which lives only in clean turbulent waters. Due to the vulnerability of young pearl mussels to pollution, the species has declined by over 80% in the last ten years. Much of the remaining population is believed to comprise adults born before Independence!
Other forms of pollution also have an impact, for example heavy metals from industrial pollution.
Metals such as aluminium can also be released from soils by acidification due to poorly sited commercial forestry. High sediment loads are damaging too. Sedimentation from farming, arterial drainage or construction can raise temperatures and physically overwhelm filter feeders and fish populations. Thresholds can quickly be reached beyond which some plant species are no longer effective against heavy metals or at which filter feeders can no longer absorb finer particulates.
6.3 E CO S YS T E M S E RV I C E S
P u ri f i c a t i o n The principal ecosystem service is the regulating one of water purification, benefiting both water abstraction and the assimilation of pollutants. Water from surface sources is highly dependent on natural aquatic systems for its preliminary purification. By comparison, groundwater is especially vulnerable to surface pollution, and its quality is greatly influenced on the frontline by soil micro-organisms. In contrast to much of Europe where much water is derived from ground sources, only one quarter of Ireland’s water comes from groundwater sources.
The aquatic ecosystem is capable of mopping up nitrates and phosphates, but has evolved in conditions where nutrients were scarce and is vulnerable to being overwhelmed by excessive quantities. Once this occurs, artificial water treatment is required for human needs, the cost of which increases as the level of pollution rises. By 2022, it is anticipated that 85% of Ireland’s rivers could require protection through treatment of effluent as their assimilative capacity will be at risk of being exceeded (DEHLG, 2005). It is perhaps ironic that much effluent treatment can be achieved through the artificial creation of wetland ecosystems. Increasing interest in reedbed systems for the treatment of waste is being shown by local authorities, industrial firms and some rural households.
Such systems even seem to be able to control bacterial pollution from e-coli, a common problem with rural water supplies due to livestock pollution and domestic sewerage. Riverside vegetation is promoted within the Rural Environmental Protection Scheme (REPS), partly to trap farm pollutants.
Fish catch The aquatic ecosystem provides a provisioning service in terms of the economic and recreational value of fish species. As a result of its separation from mainland Europe at the end of the last iceage, Ireland could not be reached by true freshwater species. As a result, the species diversity of native freshwater fish in Ireland is relatively low in comparison with the UK and the rest of Europe (Quigley & Flannery, 1996). Fully half of our total freshwater fish, including familiar species such as pike (Esox lucius) and roach (Rutilus rutilus), have been introduced and dispersed by humans (Went 1950; Moriarty & Fitzmaurice 2000). Nevertheless, Fitzsimons and Igoe (2004) contend that Ireland has some of the finest fish faunas in Western Europe as many freshwater fish communities have remained unchanged since the Ice Age. Ferguson (2004) highlights the large and unique genetic diversity of the native brown trout and pollan. Several Irish inland waters, such as Lough Corrib, Lough Mask, and Lough Melvin, are world famous as brown trout angling destinations, attracting a substantial amount of angling tourism.
Not all fish demand the highest quality water, but higher value species such as salmon typically do due to their insectivorous diet and migratory reliance on the chemistry of specific rivers. Fish and eels were important food and income sources in the past, but the number of locations where these species can now be harvested is very few. The wild freshwater catch has now largely been substituted by fish farms, although these farms themselves depend on good quality water (see Fisheries). In 2004, commercial production of trout from such farms was valued at around 600,000.
In the case of salmon, legislation has now just been passed, amidst much opposition, to close the wild commercial fishery in response to the declining catch. While various factors have had a role in the salmon’s decline, poor water quality has certainly been one factor. At around 139,000 fish, the catch had fallen to just 64% that of just four year’s earlier and is only a fraction of that caught in the past. Although, as a result, wild salmon attract a premium price, the value of the commercial share had fallen to just 4 million per year (Indecon, 2003). The decision to close the commercial fishery was partly due to recognition that the recreational value of an individual salmon is worth up to 1,000 compared to between 25-60 for a netted wild salmon. The total value of the recreational fishery has been estimated at between 11.5 million and 15 million.6 W e t l an d s A further ecosystem service is produced by wetlands. In Ireland, peatlands are a distinctive wetland feature of the cultural landscape. Although of no use to groundwater recharge, peatlands act as a sponge, absorbing water at times of high rainfall and so acting as a buffer against flooding. Surface mosses are highly efficient at absorbing water and are of horticultural value for precisely this reason. As such, peatlands and their vegetation regulate the flow of water with consequent economic and social benefits. Given that raised and blanket bogs are dependent on the collection of nutrients from the air and from precipitation, they also possess a highly specialised biodiversity.
Peatlands are also of major benefit in offsetting global warming. Although they do release methane, a potent greenhouse gas, they also act as carbon store, without which huge quantities of CO2 would be released into the atmosphere. Releases of this nature, due to the deforestation of tropical peatlands in Indonesia, are thought to have contributed up to 40% of global greenhouse gas (GHG) emissions in 1997 and 2002 (Page et al, 2002), but are not currently included in national calculations in relation to the UN Convention on Climate Change. In Ireland, carbon emissions are occurring directly due to the burning of peat as fuel, but also indirectly as bogs dry out in response to the drainage undertaken to facilitate peat harvesting. While conversion to agriculture has virtually ceased in response to agricultural policy reform, the drying out is continuing due to current harvesting and past drainage. This is leading to a corresponding release of carbon and methane. A healthy surface flora is representative of a stable bog, but also minimises its desiccation. Potentially, drains can be blocked and bogs re-wetted to permit the establishment of a peatland ecosystem.
6.4 E CON O M I C A N D S O C I A L VA LU E S Water is both a public good and a private good. The economics of water use includes a sizeable element of external costs in that pollution by agriculture, industry and the domestic sector presents a social cost to downstream users. Furthermore physical abstraction by these sectors reduces the ecosystem’s capacity to maintain clean water, particularly during periods of low flow. Agriculture is in the position of being the biggest user and polluter of water sources.
Polluted water presents a significant health risk. The greatest threat is presented by heavy metals from industry, mining or natural sources. The ecosystem is unable to mitigate this pollution which The 11.5m. figure was estimated by Indecon, of which 6.5m.is due to visiting anglers. In his submission to the Oireachtas Ctte, consultant, Michael Nealon believed that the value of the latter is at least 10m.
can be exacerbated by acidification. Fortunately, pollution by heavy metals is rather rare in Ireland.
Rivers and lakes in Ireland are relatively clean compared with some other European countries.
Nevertheless, the recent cryptosporidium outbreak in Galway demonstrates the result of complacency in not providing adequate control of pollution or of water purification. Twenty-nine percent of rivers are classed as being slightly or moderately polluted (EPA 2005) mostly due to nonpoint source pollution from agriculture, particularly of phosphates and nitrates. Nitrate is the greater threat to health and considerable amounts are being spent to reduce nitrate pollution under the Nitrates Directive, for instance through 39 million of investment under the Farm Waste Management Scheme as well as through REPS. The health risk from nitrates is confined largely to groundwater sources, although only around 2.6% of sources are reported to have elevated levels (EPA, 2002). Biodiversity has a positive impact by recycling the nitrates before water filters down to groundwater.