Introduction
The rate and nature of land use changes indicate where future environmental pressures are likely to arise. By European standards, Ireland has experienced a relatively high rate of land use change since the early 1990s.
Land is subject
to many competing demands. We rely on our land resource for food, energy, forestry,
recreational opportunities and overall, for a good living environment. Current
land use is the result of a sequence of past human interventions on the natural
landscape. Agriculture remains the predominant land use in Ireland, although
economic development and population growth since the mid 1990s, have led to an
increase in the extent of built-up areas, with growth rates surpassing those of
our European neighbours.
The soil of
Ireland is an immensely valuable, and finite, national resource, which forms
and evolves slowly over very long periods of time. Soil is a biologically
active, complex mixture of weathered minerals, organic matter, organisms, air
and water that provides the foundation for life in terrestrial ecosystems. The general consensus is that soil quality in
Ireland is good; however, this is based on limited information.
State and Impacts
Land Cover
Irish land cover is primarily agricultural, followed by bogs and wetlands and forestry. The Irish landscape has experienced continual land cover changes for centuries, but there has been a relatively high rate of land use change by European standards since the early 1990s. For example, the area under forestry has increased a quarter to over 10 per cent of national land cover, and the area of artificial surfaces (residential and industrial buildings, roads etc.) increased by approximately 15 per cent since 2000 to 2.3 per cent of land cover. There has been significant development on the periphery of many urban areas across Ireland. Similarly, rural areas have experienced widespread construction of single rural dwellings and the suburbanisation of villages close to towns and cities.
Approximately 75 per cent of the national forest estate is predominantly conifer, comprised mainly of commercial timber species but also including some native species such as Yew and Scots Pine. The remaining 25 per cent of the forest estate is predominantly broadleaf and mixed forest, of which approximately half is comprised of native broadleaf species such as Oak, Ash, Birch, Hazel, Alder etc. The proportion of broadleaf to coniferous species planted in recent years has increased, although the actual levels of planting have remained somewhat static.
Soil
A limited amount of information is known about Irish soils, but a late introduction into the industrial revolution preserved our soils from large amounts of contamination. The large percentage of permanent pasture land and our temperate climate have protected Ireland’s soils from serious degradation. The general consensus is that soil quality in Ireland is good; however, this is based on limited information and therefore the degree of certainty is low. The production of a National Soils Database (2007) and the EPA Historic Mine Sites – Inventory and Risk Classification project (2010) has provided much needed baseline knowledge on soils in Ireland.
Forestry
Following a long period of afforestation, which began in 1904, forest cover has increased from 1 per cent to over 10.7 per cent of land cover. This compares with a European average of over 30 per cent. The strategic plan for the Irish forestry sector sets a national planting rate target of 20,000 ha per annum, and a target for forestry to reach 17 per cent of land cover by the year 2030. Recent planting rates have fallen well short of this target.
Drivers & Pressures
Land is subject to many competing demands. Current land use is the result of a sequence of past human interventions on the natural landscape.
The principal causes of land use changes in urban areas have been the development of housing and associated commercial services built to cater for the growth in the population and the migration to suburbs, satellite towns and villages. In the 25 years between 1970 and 1995 an average of 23,000 new homes were constructed in Ireland every year. In the ten years between 1996 and 2007 an average of 60,000 homes were constructed per year, peaking with 93,000 in 2006. In recent years however, there has been a significant fall-off in new housing completions with a total of 10,000 completed in 2011.
A natural consequence of peripheral urban development is increased traffic volume; this often results in congestion and longer commuting times. As some villages and towns grow beyond the capability of the local infrastructure to support them, overloaded wastewater treatment plants or inadequate drinking water supplies pose a risk to health and the environment.
The scattered nature of Irish rural development has made the provision of public services, including wastewater services, more expensive and less economically viable. In many rural areas the majority of the population uses individual septic tanks, which pose a risk of pollution of groundwaters, surface waters and public water supplies if poorly sited and/or not properly maintained.
Other threats to Ireland’s land resource arise from intensification of agriculture, poorly managed commercial forestry, peat extraction, land clearance and development.
Soil can be contaminated by a wide range of potential pollutants, through either local (point source) contamination or diffuse contamination. Contamination from point sources can arise as a result of leakages and accidental spillages from commercial activities e.g. petroleum storage tanks, old gas work sites, timber treatment or landfills. Diffuse contamination can arise from activities such as agriculture, forestry, horticulture and landspreading of organic wastes.
Responses
Strategic Environmental Assessment
The EU Strategic Environmental Assessment (SEA) Directive became a legal requirement in Ireland since 2004. The main objective of SEA is to provide environmental protection and to implement environmental considerations into plans and programmes with the promotion of sustainable development. SEA is mandatory for certain plans/programmes in the areas of agriculture, forestry, fisheries, energy, industry, transport, waste management, water management, telecommunications, tourism, town and country planning and land use.
Of the sectors specified in the Directive, Land Use Planning has had the most significant take-up. While many of the economic sectors are now beginning to address the requirements of the SEA Directive, it is notable that a number of significant sectors, in particular the forestry, tourism and telecommunications sectors, have yet to engage fully in the process. The effectiveness of SEA in Ireland is currently being assessed through a study initiated by the EPA.
Historic Mine Sites
An inventory and assessment of historic mine sites was published by the EPA and the Geological Survey of Ireland in 2010. This concluded that of the 32 mining districts assessed, 22 districts will not require any interventions, seven districts will require further monitoring and three districts (Tynagh, Silvermines and Avoca) will require additional site-specific risk assessment by the landowners. A comprehensive remediation project is currently underway at the Silvermines site, while a full assessment of the Avoca site, where the State is the landowner, has recently been completed.
Soils
A National Soils Database (NSDB) has been developed through a research project funded by the EPA. This database has provided Ireland with a baseline soil geochemical atlas. It provides data point and spatial distribution maps for 45 elements, including major nutrients such as phosphorus and potassium, as well as trace elements. The Irish Soil Information System project is a current research project funded by the EPA and being undertaken by Teagasc. This aims at producing a national digital soil map at a 1:250,000 scale with the associated soil information system for Ireland by 2014. The latest spatial mapping technologies are being utilised for this project, bringing soil mapping into the 21st century.
Outlook
The trend earlier in
the decade towards a continuation of market-driven, low-density residential
development on the periphery of cities and the suburbanisation of satellite
villages and towns has come to an abrupt end.
The collapse of the property market, a slow recovery from economic
recession, as well as a significant deficit in public finances means that it is
likely to be some years before there is pressure again to convert significant
amount of land for development purposes.
Nonetheless, the issues
of spatial planning, land use and soil quality are intertwined and
interdependent, and this should be reflected in integrated policies and plans
at national, regional and local level. The continued uptake of the SEA Directive
across all economic sectors will therefore be important.
It
is possible that many soil threats and pressures, such as erosion, surface
sealing and compaction, are occurring in Ireland, but no comprehensive
assessment has been made to date. These threats, along with the potential
impacts of climate change, need to be evaluated, quantified, prioritised and
addressed.
While
Ireland has fewer contaminated land problems than most other heavily
industrialised countries, there is no overall policy framework for the
identification, management and remediation of contaminated land in Ireland.
National legislation dealing specifically with soil contamination needs to be
developed, including a mechanism for remediation of sites.
