«The Economic and Social Aspects of Biodiversity Benefits and Costs of Biodiversity in Ireland REPORT PREPARED BY: CRAIG BULLOCK, OPTIMIZE CONSULTANTS ...»
The principal adverse impact arises from fragmentation of habitat. Fragmentation has been a feature of more intensive farming and is certainly an outcome of much built development such as housing. Invariably, new roads present a significant risk of habitat fragmentation. As habitats become smaller and less continuous their functional integrity is reduced and their reduced size increases the prospect of their being over-looked when it comes to future development. As such, habitat fragmentation affects all species, although it is obviously a greater problem for mammals. As well as the inevitable physical danger posed by roads, breeding populations can also be reduced to below sustainable levels. The reduced opportunity for migration also inevitably increases the vulnerability of species to climate change. Fires caused by cigarettes or broken glass discarded by passing motorists may worsen this risk as summers become drier and hotter.
On the other hand, roads can provide new linear habitats. Motorway verges are often planted with trees, typically now native trees, and an absence of subsequent intervention or infrequent mowing can provide a quality habitat. It’s a habitat that does not suit all species given the proximity of traffic and regular interception by junctions or overbridges, although some species such as the aforementioned kestrel can benefit from the vegetation growth and background noise. The linear habitat also compensates, albeit partially, for the fragmentation of previous habitats. Although, this has, in some instances, benefited the spread of invasive non-native species.
Pollution can be a problem. Run-off from the road surface can deposit pollutants such as petrochemicals into adjacent watercourses. Local authorities may also be less than cautious in their application of herbicides. Major new roads normally include sites for holding ponds to retain such run-off, but pollution is a problem on many existing roads.
A further problem is that the improved accessibility typically encourages new built development which can lead to the loss of adjacent habitats. Although such potential cumulative impacts should be identified by the environmental impact assessment, subsequent local planning decisions may pay inadequate attention to minor habitats.
7.2 R E L E VA N T S P E C I E S A N D E CO S YS T E M S E RV I C E SAlthough it may sound bizarre to talk about ecosystem services in the case of roads, there are some indirect benefits from mitigation. For example, roadside trees capture polluting dust particles and also mitigate noise levels.
These benefits can be over-stated, but appear to be highest for the first line or two of trees and diminish rapidly beyond these. In addition, as noted above, holding ponds containing reedbeds and their associated species perform the value of removing pollutants before they can find their way into the wider environment. There are ecological benefits from these services, but the principal benefits are in terms of human health and well-being.
Aside, from the benefits there are particular species which are at risk from roads. These include:
• Badgers. Badgers are a protected species under the Wildlife Acts 1976 & 2000 and sets cannot be disturbed. The NRA therefore aim to identify sets prior to construction. In cases, where a set is in the direct line of a road, efforts may be made to temporary relocate the population to a new location. More typical, though, is for underpasses to be provided together with badger proof fencing along the road. These mitigation measures are, of course, far from perfect, especially as badgers may be drawn to roadside habitats to forage.
Furthermore, older roads will not possess such mitigation even though they are likely to be carrying far more traffic than at the time they were first surfaced. Dead badgers are a frequent siting along roadsides.
• Otters. These mammals are widespread in Ireland, although they usually exhibit a low density population. As such, they are susceptible to habitat fragmentation. The width of major roads is a deterrent to otters using underpasses, but new roads now tend to channel minor streams under roads using a slightly meandering course with an accompanying raised platform.
• Bats. Detailed guidelines exist to minimise the danger to bats from tree-felling, timing of works, damage to roosts, building demolition, bridge restructuring or lighting following road opening. In this respect, bats are typically better protected with major road schemes than with built developments or renovations where the need for protection is often ignored by developers. However, there are still problems where roosts or territories go unidentified.
• Deer. As two of Ireland’s three species of deer are non-native and present a nuisance for forestry, mitigation measures are typically restricted to the erection of deer proof fencing to avoid collisions. Speed restrictions may be imposed where deer are present. Native red deer live in the remoter areas of Ireland, but mitigation measures such as underpasses are used in other European countries.
7.3 E N V I R ON M E N TA L I M PA C T A S S E S S M E N TAll large public infrastructure developments are subject to environmental impact assessment under the EC Directive 85/337/EEC. So too are larger private developments which have implications for land use, public well-being, and air or water quality. Specialists are contracted to identify and assess potential impacts as they affect human beings, flora, fauna, soils, water, air, climate, landscape, material assets and cultural heritage. On the basis of these investigations, mitigation measures or alternative development options are proposed.
Where roads are concerned, the National Roads Authority issues guidelines on impact assessment.
It also has a dedicated Environmental Section. For specific projects, assessment usually commences with a constraints study of the likely impacts of alternative route options. This is followed by a more detailed Route Selection Report at which stage a limited amount of fieldwork is typically undertaken. Finally, once a preferred route has been selected, an environmental impact study is commissioned. Assessment is usually along a route corridor within which some degree of realignment is possible in the event that significant impacts are identified. However, this does not preclude a re-routing of a section of road in the event that serious impacts are predicted. At present, the use of cost benefit analysis in road development is limited to an assessment of journey time savings and accident costs and takes no account of full economic costs over time, including biodiversity (Ozdemiroglu & Bullock, 2001). The limited scope of CBA is arguably a factor which contributes to the NRA’s preference for new routings over the more extensive renovation of existing routes. New routes have high time savings, low accident rates and low impacts on existing material assets, but possibly greater impacts on biodiversity and landscape which are not quantified in the same manner.
EIA does not explicitly consider biodiversity. Rather, assessments are made of flora and fauna and these record, species presence and vulnerability, as well as their dependence on habitats and external inputs such as aquifers and water supply. Seasonality can be a problem given the timing of site investigations. Indirect or secondary impacts are also relevant. It has been argued that by proposing a cutting for the Kildare Bypass with its possible implications for the aquifer recharge to Pollardstown Fen National Nature Reserve, Kildare County Council gave greater weight to equine and landscape concerns than potential ecological impacts.8 Whatever the truth of the matter, the issue delayed the bypass by three years. An impermeable membrane was eventually provided at an additional cost of 5 million. The ultimate cost of the bypass had risen to 160 million from initial estimates of 70 million.
The EIA process is comprehensive, but is subject to some weaknesses in implementation. A common complaint concerns objectivity in that consultants are appointed by a client who is typically the developer or a public agency charged with infrastructure development. This is not necessarily as serious as it sounds in that EIA is directed at removing the causes of adverse impacts prior to development consent. Furthermore, consultants have a professional reputation to maintain and would be aware that their findings are open to scrutiny within a possible oral hearing. Lack of objectivity is possibly a greater prospect with smaller private projects where an appeal to An Bord Pleanala or an oral hearing is not expected. However, ecology is likely to be less of a casualty than the supposed “soft” social sciences.
One further weakness of EIA is its limited scope. Although some attention is given to interactions between different impacts, EIA makes no allowance for a quantification of non-market or external costs as they affect human beings. A further characteristic of the limited scope of EIA is its restriction to a single project. The assessment is required to consider cumulative impacts, but these can be rather tenuous. Road construction commonly presents a cumulative impact in that built development may follow in its wake. Although the road builder is required to adopt mitigation measures proposed by the specialist, it is difficult for the Environmental Impact Statement to address cumulative impacts which are long-term or uncertain. Furthermore, whereas the road builder must adopt the mitigation measures included in the EIS, subsequent new developments are not so constrained. The developer or planner may ignore this advice or simply be unaware of it.
Newsletter of the Irish Waterways Association of Ireland (2004).
Strategic Environmental Assessment should compensate for the project-based limitation of EIA.
SEA is directed at policy rather than projects and, specifically, the sustainability of policies. It aims to focus on key environmental constraints rather than to collect the more comprehensive data of an EIA. To date, SEA in Ireland has only been required of local authorities in the preparation of development plans. More often than not this process has extended only to an elaboration on the environmental proofing of intended policies. This is unfortunate as SEA is the ideal means through which to examine the wider implications of development as they affect topics such as biodiversity.
For roads, the main adverse impact on biodiversity arises from habitat fragmentation. However, the implications of this impact are impossible to examine at the level of an individual project using EIA.
The assessment of climate impacts is similarly compromised.
7.4 CO S T O F P R OT E C T I ON While the NRA has detailed guidelines on the measures that should be taken to avoid ecological impacts, there have been no assessments of the cost of these measures. Inevitably, costs vary enormously between schemes depending on the nature of the landscape. In addition, it is very difficult to isolate these costs as, under Design and Build Schemes, the road builder frequently provides a lump sum estimate of the amount spent on all environmental works, including visual and noise mitigation and earthworks. The NRA are currently looking into the costs of environmental mitigation. In the immediate term, the best that can be done is to use the NRA’s guide prices for road features of relevance to biodiversity and apply these to a typical 10km of dual carriageway. For this length of road an ecological impact assessment might cost 20,000 while mitigation measures to protect habitats and water quality could cost 45,000.9 The figure excludes the costs of stockproof fencing, earthworks, planting and the costs of road diversions around ecological features.
Given the length of new road constructed each year, this suggests a total annual cost of at least 35 million.
Assuming two badger underpasses @ 4500, 50 bat boxes @ 210, 20 sediment trap @ 540 and 2 retention
EPA (2002). Guidelines on the information to be contained in Environmental Impact Statements.
National Roads Authority (2000) Working for Sustainable Progress while Conserving our Environment, Irish Times, Business 2000.
Ozdemiroglu, E. & Bullock, C. (2001). Cost-benefit Analysis of Roads, EPA.
Therivel, R. (2004) Strategic Environmental Assessment in Action. Earthscan, London.