Dec 2, 1999 - Value in wetness: the environmental capital of the Humberhead Levels. 4.1 Introduction. 4.2 Main .... development and/or implementation of environmental policy. ('Wise use and .... Food web support. Biomass production.
THE SOCIAL, ECONOMIC AND ENVIRONMENTAL BENEFITS OF WETLANDS IN THE HUMBERHEAD LEVELS STAGE I REPORT By D.V.Hogan, E.Maltby and M.Mode Wetland Ecosystems Research Group, Royal Holloway Institute for Environmental Research Huntersdale Callow Hill Virginia water Surrey GU25 4LN
CONTENTS 1. Introduction 1.1 Definition of wetlands 1.2 Wetland loss and degradation 1.3 Benefits of wetland protection and conservation 1.4 Functioning of wetlands
2. A functional approach to wetland assessment
2.1 Overall approach 2.2 Structure of the project 2.3 Review of the functional characteristics of wetlands in the Humberhead Levels 2.4 Wetland processes, functions and values 2.5 Wetland functional assessment 2.6 Data collection for Functional Assessment Procedures (FAP) 2.7 Identification of wetland functions, goods, services and values 2.8 A functional classification for European wetlands 2.9 Structure of the classification 2.10 Wetlands and water management
3. Functional assessment in Humberhead levels
3.1 Establishment of a wetland inventory 3.2 Identification of small-scale landscape units 3.3 Potential functioning of wetlands 3.4 Opportunities for wetland regeneration 3.5 Mapping wetland functional units 3.6 Transfer of map information to a GIS
4. Value in wetness: the environmental capital of the Humberhead Levels 4.1 Introduction 4.2 Main steps of the EMC approach
4.2.1 Definition of the purpose of the exercise (step A) 4.2.2 Dividing the Humberhead Levels area in distinct units (step B) 4.2.3 Identification of the environmental attributes and services for sustainability (step C) 4.2.4 Evaluation (step D)
5. The Environmental Capital and Wetland Functional Assessment methodologies 5.1 Background 5.2 Benefits of the approaches 5.3 Opportunities for the use of FAP within steps of the ECM
6. Further actions
6.1 Work in Stage 2 6.2 Integration of wetland issues 6.3 Development of FAP 6.4 Strategy for wetland conservation
References Tables Table 1 Wetland status categories Table 2 Key functions and supporting processes in river marginal wetlands Table 3 Objectives of wetland assessment Table 4 Hydrological codes for river marginal wetland sub-types Table 5 Landscape units, hydromorphic soils and their locations within the Humberhead Levels Table 6 Soil associations and wetlands Table 7 Wetland status in SSSIs Table 8 Potential functioning of present wetlands in the Humberhead Levels Table 9 Potential functioning of presently degraded (restorable and non-restorable) wetlands of the Humberhead Levels Table 10 Candidate 5x5km areas occurring on published soil maps Table 11 Application of ECM to issues raised within the Humberhead Levels Table 12 Comparison of the step required to carry out the Environmental Capital and Functional Assessment Procedures Table 13 A strategy for wetland conservation in the Humberhead Levels
Figures Figure 1 Wetland processes, functions and values Figure 2 Structure of the European wetland classification Figure 3: Flowchart showing the main steps of the ECM approach (Countryside Commission et al., 1997). Figure 4. Predicted undershoot condition, requiring defensive or protective management actions. Figure 5. Predicted overshoot condition, ordinary management strategies are sufficient. Figure 6. Predicted on target condition, the existing management strategies are designed to satisfy the DL with the current service trend TR.
1. INTRODUCTION 1.1 Definition of wetlands
Wetlands are often described by words such as bog, fen, mire, marsh and swamp, all of which suggest a particular kind of habitat in which water is crucially important. In simple terms, as the name suggests, wetlands can be thought of as occupying those intermediate areas between dry land and aquatic ecosystems, and as such have several important characteristics in common with both. They are at least seasonally waterlogged, have physical, chemical and ecological properties dependent on the timing and nature of water movements, and the plants and animals they support often possess specialist adaptations for life in saturated conditions. Although a universally acceptable wetland definition has not yet been agreed, the main characteristics used in defining wetlands are: 1. Wetlands are distinguished by the presence of water, either at the surface or within the root zone. 2. Wetlands often have unique soil conditions that differ from adjacent drier uplands. 3. Wetlands support vegetation adapted to wet conditions
1.2 Wetland loss and degradation According to some experts, the world may have lost half of its wetlands since 1900. Though this could be overstated for developing countries, it is no exaggeration for the developed world, where drainage has long been seen as a progressive, public spirited activity, which enhances the health and welfare of human society. It is important to appreciate that whereas wetland loss represents an absolute and final disappearance of the resource, exploitation and degradation still allow the possibilities of wetland restoration by the reduction of damaging impacts. The status of wetlands and the consequences for the delivery of functioning, are major considerations within the Humberhead Levels, given the degree to which alterations have taken place to convert the area from one largely of wetland to one of intensive agricultural production. The challenge today is to develop practical means of wetland conservation and restoration, in balance with other uses, which are based firmly on the many human as well as ecological benefits that wetlands can provide. The changes which can be caused to wetland ecosystems are many and varied. They range from a reduction in area to an alteration in the way they work, from direct and planned effects to indirect, often unintentional ones, from immediate point source impacts to diffuse impacts with gradual long-term and/or chronic degradation, and from local to catchment, regional or even continental scale. The changes also vary from temporary to permanent and irreversible, as discussed below.
1.3 Benefits of wetland protection and conservation The conservation and good management of wetlands can provide a substantial range of environmental benefits including: Improving water quality for the benefits of fisheries and the general health of the river corridor (buffer zones) Providing a water supply for stock Reduction of flood risk downstream Helping to maintain river levels during dry times of the year Providing summer grazing when production on drier land may be limited by droughtiness Wildlife conservation, providing habitats for increasingly rare species of plants and animals Forming important elements of the landscape, contributing to the overall beauty of the
countryside and providing some of the special characteristics of the locality Providing an educational resource for schools and other groups Alternative sources of income such as biofuel (willow coppice) Peat preserves pollen and archaeological remains, which form a record of past landscapes and human activities The destruction of wetlands removes the possibilities of these benefits, a fact realised increasingly as nitrate concentrations in streams and groundwaters have increased generally. An environment rich in wetlands has the potential, for example, to reduce the potentially harmful impacts of current and/or past fertiliser use in a particular area.
1.4 Functioning of wetlands Wetlands represent some of the most abused ecosystems on the planet and are posing some of the most contentious questions to both scientists and policy makers. This emphasis is simply illustrative of a wider functional significance of wetland ecosystems. Despite the growing scientific evidence for their importance to the health and welfare of human communities and wildlife as well as key aspects of environmental quality and stability, the special significance of wetlands is only gradually permeating societal decision-making. This is due at least in part to a lack of linkage between the science and policy instruments. The approach to wetland protection has been necessarily site-based reflecting, in part, the practical considerations of land ownership and the requirements imposed by legal instruments. Policy frameworks, where they exist, have been similarly structured with an emphasis on site designation rather than on an ecosystem, or catchment-based approach (e.g. European Council Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora ). Research over the last 20 years aimed at improving the understanding of wetland ecosystems has demonstrated the potential importance of these ecosystems in the provision of goods and services and a wider significance beyond more traditionally held values of habitat uniqueness and rarity (Maltby et al., 1994). Studies of fundamental processes have demonstrated that wetlands are capable of performing ecological, hydrological and biogeochemical functions that may support socially, economically and ecologically important values. However, exploitation, degradation and destruction of wetlands through a range of human impacts have reduced the capacity of the resource to provide these values. Wetland functioning therefore needs protection and restoration; this is made difficult by: the complexity of associated social and economic issues, limited ability to predict or assess ecosystem functioning , the limited interaction between natural and social scientists, the limited interaction between the scientific community and decision-makers charged with the development and/or implementation of environmental policy (‘Wise use and conservation of wetlands’, EC COM (95) 189). In response to this, a new approach to understanding wetland functioning has developed, based on hydrogeomorphic principles which consider the underlying hydrological and geomorphological (landform) characteristics and processes that determine the functioning of wetlands. Wetland functional assessment is achieved by sub-dividing the wetland into a series of hydrogeomorphic units (HGMUs) of uniform functioning, based on observations of hydrological and geomorphological (landscape) features and associated processes (Maltby et al, 1996). Hydrogeomorphic principles have also been applied to develop a functional classification of wetlands (Simpson 2000). This uses evaluation of wetland hydrological source, dynamics and geomorphological setting to categorise and infer a level of potential functioning to a wetland.
Sustainable management of wetlands also requires account to be taken of social and economic as well as environmental values, which means that any evaluation technique needs to link all these elements. The functional approach is capable of doing this due to its holistic expression of the way an ecosystem works, in terms that are more broadly understood and easily translated into the social science and economic disciplines. However, the natural science and economic definitions of wetland functions are still somewhat at variance. To the natural scientist functions are actions or activities that arise from the interaction of natural processes with ecosystem structure. Conversely, to the economist wetland functions are synonymous with the values that they generate for humans. The functional approach to wetland assessment and the development of Functional Assessment Procedures (FAP) fits well with the holistic objectives of the Value in Wetness project. FAP is designed to enable assessment of a wetland for a range of hydrological, biogeochemical and ecological functions by non-specialists from a variety of backgrounds and disciplines. FAP also compliments the Environmental Capital Methodology (ECM), comparison with which is made in Table 9, enabling its use in identifying a comprehensive range of ecosystem characteristics, capable of delivering sustainable environmental benefits with appropriate sensitive management.
2. A FUNCTIONAL APPROACH TO WETLAND ASSESSMENT 2.1 Overall approach The research aims to identify the main functions of wetlands in the Humberhead Levels (HHLs) and evaluate these in a way that can highlight the social, economic and environmental benefits that wetlands in this region can provide. This will be achieved by the application of functional concepts, principles and evaluation tools developed by WERG and their linkage to the ECM developed by Land Use Consultants and CAG. The main objectives of the project are to: 1. Characterise and produce an inventory of wetlands in the HHLs using a functional approach on a GIS platform 2. Conduct a functional assessment of a representative subset of wetlands in the HHLs for extrapolation to the whole area 3. Evaluate the wetlands in the HHLs for selected values through the application of the structure and principles of the ECM 4. Link the functional approach and the ECM to enable smooth transition between functional evaluation and social, economic and environmental valuation
2.2 Structure of the project Stage 1: Characterisation and production of an inventory of wetlands in the Humberhead Levels Stage 2 Functional assessment of wetlands in the Humberhead Levels Stage 3 Extrapolation of findings to the catchment scale
The work of Stage 1, reported here, is described under main headings used for the original proposed project structure.
2.3 Review of the functional characteristics of wetlands in the Humberhead Levels In order to define and characterise the wetland resource of the Humberhead Levels, it was necessary to identify wetlands in terms of their condition or status, as shown in Table 1. This has been carried out initially as a desk exercise but will be refined later in the project, as necessary, through consultation with local stakeholders involved in the Value in Wetness initiative.
Table 1 Wetland status categories Wetland status
Functioning
Management
Intact/primary
Performs one or more functions well Formerly degraded but now performs one or more functions well
Likely to require continuation of appropriate management Likely to require continuation of appropriate management
Intact/artificial
On artificially displaced land, performs one or more functions well
Likely to require continuation of appropriate management
Degraded/restorable
Functioning reduced or lost due to Damage reversible (eg by raising water management as other than levels) but recovery may be only partial wetland
Degraded/non-restorable
Functioning reduced or lost but may retain environmental capital
Destroyed
Complete loss of wetland functioning
Intact/restored
Damage not reversible at present for operational, social or economic reasons, but future circumstances (eg climate change scenarios, Palmer and Holman 2000) may permit some recovery Losses such as peat mining, drainage for landfill or urban development. Return of wetlands requires re-creation, which is unlikely to restore former functions
Intact wetlands can be expected to perform (at least some) functions well and require the continuation of appropriate management. Intact/primary wetlands will have developed often with long-practised traditional management such as grazing or mowing, but without major physical disruption. Intact/restored wetlands will have experienced a past phase of major disruption and physical change, such as peat cutting, but present management, such as cessation of cutting and raising of water levels, aims to mitigate damaging effects and restore wetland functioning. Also includes areas formerly drained but rewetted due to subsidence. Intact/artificial includes wetlands which have developed or been created on land substantial altered but subsequently abandoned from a former industrial use such as mining or railways. Degraded (restorable) wetlands have usually been managed other than as wetlands but damage to wetland functioning is to some extent reversible. These wetlands have the potential for hydrological restoration, often by reversing the damaging impact i.e. re-wetting by raising water levels, which had been previously lowered by artificial drainage. However, there can be complications and complete reversal and re-establishment of functioning may not be possible. For example while restoration would probably be possible with many mineral soils (gleys), the situation with organic soils (peat) could be that drainage led to irreversible drying and hardening, precluding re-wetting on raising water levels. Restoration of functioning may be variable, with only certain functions becoming operative (eg the re-establishment of buffering capacity but not the original habitat type).
Degraded non-restorable wetlands are those which, for present practicable purposes, are not candidates for restoration within the HHL due to present economic and/or social circumstances. This includes highly productive, intensively farmed land which is currently maintained by artificial drainage. However this does not rule out the possibility of some restoration of wetland functioning in the future, and in that sense retains environmental capital. Palmer and Holman (2000) indicate the soils which could support wetlands if the sustainability of present land use became questionable through the effects of climate change. There may also be opportunities for restoration of some wetland functioning within the context of intensive agricultural use, such as modifications to ditch management, and permitting patches of wetland to develop in low lying spots. Adjustments to artificial drainage systems allowing water levels to rise within subsoils and so reduce the requirements for irrigation may enable wetlands to be created in low-lying positions. Possibilities here will be investigated in Stage 2. Destroyed wetlands may result from complete removal (eg commercial mining of peat for fuel or horticulture) or drainage and replacement for landfill or urban development. Returning wetlands to these areas involves re-creation, following which it is unlikely that former functions can be reinstated, though valuable alternatives are often possible.
2.4 Wetland processes, functions and values Processes are those physical, chemical or biological changes or reactions that take place naturally within ecosystems. Processes interact with the ecosystem structure to deliver activities or actions known as functions, which can be conveniently grouped as hydrological (eg floodwater retention), biogeochemical (eg nutrient export) and ecological (eg ecosystem maintenance). Wetland functions can provide goods such as agricultural products or fisheries, services such as flood control and water quality maintenance, and have attributes including biodiversity and cultural uniqueness. Together these factors provide values to society, which are capable of supporting economic, social and environmental development objectives. The relationships among these concepts for river marginal wetlands is shown in Figure 1.
2.5 Wetland functional assessment Assessing the functional performance of a wetland enables more effective judgements to be made of its importance, and decisions to be made more effectively and logically about its protection and management within the context of a wider catchment or landscape scale. In general, wetland assessment tools give a prediction of functioning based on the best available knowledge and information on wetland processes. However this information may often be subjective, where it is based on specific studies, literature and specialist opinion, and these methods do not assess the rates or dynamics of ecological processes. This expert knowledge is translated into a prediction of functioning which may take one of many forms including indices, qualitative statements and qualitative scoring systems. A review of the wetland functional assessment tools currently available is given by Hruby 1999. The WERG has been collaborating in series of interdisciplinary collaborative research projects, funded by the European Commission (DGXII), to develop tools for functional assessment of European wetland ecosystems (Maltby et al 1996), initially focusing on river marginal wetlands. At the current stage of development, the Functional Analysis Procedures (FAP) are in a prototype form, that has been developed as a demonstration version for subsequent development and tailoring to the requirements of specified users. In this sense it is not yet a finished product but contains the fundamental concepts and underlying structure that can be used as the basis for user-specific assessment tools. The key functions and supporting processes in river marginal wetlands are
indicated in Table 2. Further details of the FAP methodology will be given in the Stage 2 report, which will include the results of functional assessment carried out at specific locations within the Humberhead Levels. During Stage 2, wetlands will be defined in terms of broad functional types using hydrogeomorphic characteristics, together with their status and consequent functional integrity, that is, their capability of delivering socially, economically and environmentally beneficial functions.
2.6 Data collection for Functional Assessment Procedures (FAP) The FAP give guidance on the kinds of data which are required in order to carry out functional assessment (to be described in the Stage 2 report). Discussions were held with staff from a range of organisations to ascertain the type, quality and availability of data, especially in digital format for use with a GIS. A number of key reports and other papers were obtained and the following meetings were attended by WERG staff. 2nd December 1999: Value in Wetness Conference, Bawtry
Presentation by Chris Baker on wetland functional assessment and the benefits of wetlands to the Humberhead Levels. Outline of the WERG contribution to the project. 7-8th September 2000:Countryside Agency, Leeds
Visit by David Hogan to meet staff of FRCA to discuss digital data sources and availability(Appendix I), and to attend a meeting of the Project Steering Group with representatives of The Countryside Agency, English Nature, The Environment Agency and Grantham, Brundell and Farran, consulting engineers representing the Internal Drainage Boards for the Humberhead Levels. 6th December 2000: Value in Wetness Conference, South Cave
Presentation by Edward Maltby on the wider potential benefits of wetlands
Figure 1 Wetland processes, functions and values
Processes
Ecosystem Structure
Physical Chemical Biological
Geomorphology Hydrology Soils Fauna and flora
River Marginal Wetland Functions Hydrological functions Biogeochemical functions Ecological functions Wetland dynamics level
Attributes
Societal benefit level
Wetland Societal Values Services Flood control Water quality maintenance Food chain support
Ecological/Environmental Service Webs
Sustainable life support
Commercial utilisation
Biodiversity / Cultural uniqueness Heritage / Science
Goods Wood Plants Fish Birds
Economic Product Webs
Sustainable life support
Commercial utilisation
Table 2 Key functions and supporting processes in river marginal wetlands Function Hydrological functions (water quantity)
Processes maintaining function
Flood water detention Groundwater recharge ( and subsurface irrigation) Groundwater discharge Sediment retention
Flood water retention Groundwater recharge
Nutrient retention (N and P)
Plant uptake Storage in soil organic matter Adsorption of N as ammonium Adsorption and precipitation of P in the soil Retention of particulate nutrients Gaseous export of N by: i) denitrification ii) ammonia volatilisation Nutrient (N and P) export through land use management Nutrient (N and P) export through physical processes Organic matter accumulation
Biogeochemical functions (water quality)
Nutrient export In situ carbon retention
Ecological functions
Ecosystem maintenance Food web support
Groundwater discharge Sediment retention
Provision of overall habitat structural diversity Provision of micro sites for: Macro-invertebrates, fish, herpetiles, birds, mammals Provision of plant and habitat diversity Biomass production Biomass import via physical processes: watercourses, overland flow, wind transport
Biomass import via biological processes Biomass export via physical processes:
watercourses, overland flow, wind transport
Biomass export via biological processes: Fauna, anthropogenic means
2.7 Identification of wetland functions, goods, services and values The hydrological, biogeochemical and ecological functions of river marginal wetlands are listed in Table 2. A general assessment of their potential functioning within small-scale wetland units of the Humberhead Levels, in terms both of their present status and following restoration of degraded types is described in Tables 7 and 8 respectively.
2.8 A functional classification for European wetlands In parallel with the development of procedures for wetland functional assessment, WERG has also sought to produce a functional classification of European wetlands which would be capable of giving a rapid overall indication of potential functioning (Simpson 1999). Cowardin et al. (1979) indicate that a primary goal of a wetland classification should be “to impose boundaries on natural ecosystems for the purposes of inventory, evaluation and management”. Mitsch and Gosselink (1993) develop this further by identifying four main objectives of a wetland classification system:
1. to describe ecological units that have certain homogenous natural attributes such as vegetation type, animal species, geomorphic setting or hydrologic conditions; 2. to arrange these units in a system that will aid decisions about resource management; 3. to identify classification units for inventory and mapping; 4. to provide uniformity in concepts and terminology. While it is clear that all these objectives have to be met if a useful and robust classification is to be achieved, it is becoming increasingly apparent that the focus for wetland classification should not only describe the characteristics of a wetland but provide decision makers with pertinent information about how a wetland ecosystem functions.
Table 3 Objectives of wetland assessment Assessment type
Output
Site monitoring and research
Actual functioning – high degree of certainty
Functional assessment procedures
Actual functioning – medium degree of certainty
Functional classification
Potential functioning only
The amount and quality of information available for an assessment of functioning has a direct bearing on the degree of certainty that can be attached to a statement about how a wetland functions. During the development of the classification, and the review of activities of potential users, three levels of assessment have been identified that cover the range of detail that are required within a wetland evaluation system (Table 3). A site research project or functional assessment procedures follow methodologies that determine whether functioning actually occurs within a wetland system. Functional assessment procedures (FAP) are less costly and time consuming, and use the combination of background data and a site visit to determine functioning. The type of assessment that the functional classification can provide meets the needs of decision makers and managers, who deal with larger scale assessments, as for the Humberhead Levels, where decisions often have to be made with minimal information available on the functioning of wetlands at this scale. In addition to providing structure to decision making, a functional classification also allows a rapid assessment to be made, identifying the potential for a wetland to perform a function, enabling a user to focus attention on key wetlands for which decisions can be made about requirements for more detailed assessments of actual functioning by using FAP, as will be demonstrated for the Humberhead Levels in Stage 2.
2.9 Structure of the classification It is recognised that a pan-European classification requires to incorporate the concept of regionalisation, to cater for the biogeographical variations which occur. Information on rainfall and temperature is used to differentiate among seven biogegraphical types (tundra, alpine, boreal, western continental, eastern continental, mediterranean and atlantic). Hydrogeomorphic setting is identified on the basis of landscape position in relation to water bodies, tidal influence, marine location and the presence of extensive peatland. On this basis, five major wetland types are recognised, together with sub-types (Figure 2), which are identified by geomorphic or hydrological characteristics such as slope, hydrological inflows and outflows, or readily identifiable features such as sediment deposition or the surface form of a peat deposit. To
each subtype is given a hydrological code, based on one of the possible combinations of hydrological sources (precipitation, groundwater discharge and run off) given for that sub-type, with any surface water identified as permanent or intermittent. An example of the hydrological codes for river marginal wetland sub-types is shown in Table 4.
Table 4 Hydrological codes for river marginal wetland sub-types Hydrological setting
Groundwater discharge
H1 H2 H3 H4 H5 H6 H7 H8
* * * *
Run off * * * *
Surface overbank inundation from channel * * * *
Ppt * * * * * * * *
Identifying the wetland class provides a low level statement of potential functioning. The user works through a series of questions in order to identify the presence or absence of key hydrogeomorphic units (HGMUs), which determine potential functioning more precisely. The nine functions addressed are those covered in the more detailed FAPs (Table 2), and for each one, the likelihood of performance is expressed as follows: high potential, potential, unlikely, no potential, insufficient data available.
2.10 Wetlands and water management Reference to Table 4 helps in understanding the context of wetlands within the Humberhead Levels. Most river marginal wetlands are in category H4 (Table 4), where wetness results from a combination of a high groundwater table in the valley bottom, supplemented by periodic inundation by over-bank flooding from the rivers. Where land is embanked to prevent flooding, any remaining wetness depends upon the effectiveness of drainage lowering the water table. Wetland functioning effectively ceases to be performed where pump drainage is in operation to lower the water table. Elsewhere land where a high water table remains, due to a low-lying position or ineffective artificial drainage is classed H1. The remnant areas of raised bog are classed H8. Due to the low available relief of the area and lack of sloping ground, run-off is generally not a factor contributing to the hydrological support of wetlands in this area.
3. FUNCTIONAL ASSESSMENT IN THE HUMBERHEAD LEVELS 3.1 Establishment of a wetland inventory Previous work carried out by WERG in South West England under the Tamar 2000 SUPPORT Project (WERG 1998 and 2000) has confirmed the benefits of developing an inventory using mapped information stored on a GIS system. This enables interrogation of the data to establish spatial distribution and relationships among wetland types and other factors such as adjacent land
use and drainage networks, which determines both effectiveness and opportunity for functioning to be performed. However since digital data had not been made available to WERG by March 2001, the implementation of this aspect of the work has had to be deferred to Stage 2. The inventory will be used to assist site selection for the more detailed studies to be carried out in Stage 2. This will also require a visit by one or more of the WERG team to the Humberhead Levels to determine the requirements for the more detailed studies and to discuss important issues with local stakeholders.
3.2 Identification of small-scale landscape units The landscape sub- units identified in Palmer and Holman (2001) are appropriate to form the basis for selecting areas for more detailed study. However some adjustments have been made within the peat units; the areas of raised moss are separated from peat of the valley systems, the latter including both thick peat (peat soils) and thin peat (peaty topped mineral soils), as shown in Table 5. Preliminary assessment of potential functioning has been carried out on wetland units represented by the soil associations occurring in each sub-unit
Figure 2 Structure of the European wetland classification
Table 5 Landscape units, hydromorphic soils and their locations within the Humberhead Levels
Landscape units Landscape sub-units Alluvial flats
Marine alluvial flats River alluvial flats
Outwash deposits Outwash sands affected by groundwater
Soil associations
Main area of location
Subsidiary area(s) of location
Midelney Fladbury Enborne Conway Everingham
Everton Northern Northern Western Northern
Western, Axholme Everton Thorne
Blackwood
Axholme
Holme Moor
Northern
Western, Everton, Thorne Axholme Western Hatfield, Humber, Everton
Blacktoft Romney
Humber Humber
Axholme Northern, Axholme, Everton, Thorne
Former glacial lake
Former glacial lake
Sessay Foggathorpe
Northern Northern, Western
Thick peat
Raised bog (thick peat)
Longmoss
Thorne
Fen peat (thick)
Altcar
Everton
Adventurers’
Everton
Downholland
Everton
Thorne
Isleham
Everton
Thorne, Axholme
Thin peat
Fen peat (thin)
A preliminary identification of landscape scale wetland functional units has been based on the soil associations dominated by hydromorphic soils, as shown on the 1:250,000 scale National Soil Map (Soil Survey 1983). Information on the main soils of these associations in terms of their acting as wetlands is summarised in Table 6. However it should be noted that the associations may contain wetter soil components, which offer the main scope for wetland restoration, but knowledge of their distribution and extent is unknown or at best patchy, and will require further information to be gathered. For each Countryside Agency sub-area 1-6 of the Humberhead Levels an indication is given of the wetland status (IP=intact/primary, IR=intact/restored, IA=intact/artificial, DR= degraded/restorable, DN= degraded/non-restorable: D= destroyed - not included here), wetness class (WC) I-VI with and without artificial drainage, drainage measures employed, current land use and flood risk from the river channel. In some cases the feasibility of restoration in relation to land use and management options is at present uncertain (eg DN (DR?) and will require consultation with local experts and stakeholders for clarification.
Table 6 Soil associations and wetlands 1. Northern Area Soil Floodplains
Wetland status
Wetness Class Drained
Undrained
Drainage measures
Land use
Flood risk
Fladbury
I or DR
III
IV-VI
Pipes and ditches Wet grass
Yes
Enborne
I or DR
III
IV
Pipes and ditches Permanent grass
Yes
Romney
DN
I
II/III
Pumped and embanked
No
Holme Moor DN (DR?)
II
III
Pipes and ditches Arable (+ some grass and forestry)
No
Foggathorpe DN
III
IV
Pipes and ditches Arable and grass
No
Everington
DN (DR?)
I
IV
Pipes and ditches Arable, grass and forestry
No
Sessay
DN (DR?)
II
IV
Pipes and ditches Arable (+some grass)
No
Wigton Moor
DN (DR?)
II
III
Pipes and ditches Arable (+ some grass)
No
Drainage measures
Flood risk
Arable
Non-floodplains
Non-wetland soils: Newport
2. Humber Area Soil
Wetland status
Wetness Class
Land use
Drained
Undrained
Fladbury Blacktoft
I or DR DN
III I
IV-VI II/III
Pipes and ditches Wet grass Pumped and Arable embanked
Yes No
Romney
DN
I
II/III
Pumped and embanked
No
III
IV
Pipes and ditches Arable and grass
No
Drainage measures
Flood risk
Floodplains
Arable
Non-floodplains Foggathorpe DN Non-wetland soils: Newport
3. Axholme Area Soil
Wetland status
Wetness Class Drained
Undrained
Land use
Floodplains Romney
DN
I
II/III
Pumped and embanked
Arable
No
Blacktoft
DN
I
II/III
Pumped and embanked
Arable
No
Non-floodplains Blackwood
DN (DR?)
I
IV
Pipes and ditches Arable
No
Brockhurst
DN
III
IV
Pipes and ditches Arable
No
II
III
Pipes and ditches Arable (+ some grass and forestry)
Holme Moor DN (DR?)
No
Non-wetland soils: Worcester, Newport, Dunnington Heath, Crannymoor
4. Western Area Soil
Wetland status
Wetness Class
Drainage measures
Land use
Flood risk
Drained
Undrained
Fladbury
I or DR
III
IV-VI
Pipes and ditches Wet grass
Yes
Conway
I/DR
III
IV-VI
Pipes and ditches Wet grass
Yes
Foggathorpe DN
III
IV
Pipes and ditches Arable and grass
No
Sessay
DN (DR?)
II
IV
Pipes and ditches Arable (+some grass)
No
Blackwood
DN (DR?)
I
IV
Pipes and ditches Arable
No
Drainage measures
Flood risk
Floodplains
Non-floodplains
Non-wetland soils: Newport
5. Everton Area Soil Floodplains
Wetland status
Wetness Class Drained
Undrained
Land use
Altcar Adventurers’
I I/DR
(I)? I
IV/V (IV/V)?
Pipes and ditches Grass Pipes and ditches Arable (+grass, scrub)
Yes No
Midelney
DI/DR?
III/IV
V
Pipes and ditches Arable and grass
No
Downholland
DI/DR?
II
VI
Pipes and ditches Arable and grass
No
Isleham
DN (DR?)
I
III
Pumped
Arable
No
Blackwood
DN (DR?)
I
IV
Pipes and ditches Arable
No
III
IV
Pipes and ditches Arable and grass
No
Drainage measures
Land use
Flood risk
Arable
No
Non-floodplains
Foggathorpe DN
Non-wetland soils: Cuckney, Wick
Area 6. Thorne, Hatfield and Crowle Soil
Wetland status
Wetness Class Drained
Undrained
Romney
DN
I
II/III
Pumped and embanked
Conway
I/DR
III
IV-VI
Pipes and ditches Wet grass
Yes
II
VI
Pipes and ditches Arable and grass
No
(I)
VI
Mostly undrained; some pumped drainage for peat extraction
Foggathorpe DN
III
IV
Pipes and ditches Arable and grass
No
Isleham
DN (DR?)
I
III
Pumped
Arable
No
Blackwood
DN (DR?)
I
IV
Pipes and ditches Arable
No
Dunkeswick
DN
III
IV
Pipes and ditches Arable and grass
No
Floodplains
Downholland
DI/DR?
Non-floodplains Longmoss
I/DR
Nature No conservation and commercial peat workings
Table 7 gives an indication of the status of wetlands within designated Sites of Special Scientific Interest (SSSI) occurring within the Humberhead Levels. Though intact primary sites, such as agriculturally unimproved floodplains predominate, the proportion of restored (eg cut-over peat workings) and artificial (eg old borrow pits) intact sites indicates the potential for valuable wetlands to become established on land presently in other uses. Table 7 Wetland status in SSSIs Wetland status Landscape unit
Intact/primary
Intact/restored
Intact/artificial
1 4 2
0 0 2
2 1 4
0 0 2 0
0 3 1 0
1 0 0 1
Marine alluvial flats River alluvial flats Outwash sands affected by groundwater Former glacial lake Raised bog Fen peat Other
3.3 Potential functioning of wetlands Table 8 indicates the potential functioning of those wetlands in the Humberhead Levels identified as intact (all types) or degraded (restorable) (Table 2) using the functional classification approach. It should be pointed out that other hydromorphic soils identified in Table 2 would be capable of delivering wetland functioning, but are presently in intensive agricultural use. However, future change such as the climate change implications described by Palmer and Holman (2000)would enable wetlands to become more widely established, especially in relation to sandy soils. The full range of potential functioning in other hydromorphic soils of the Humberhead Levels is indicated in Table 8. This is based on a reduction of the effects of drainage, though assumes current flood defence embankments remain intact.
Table 8 Potential functioning of present wetlands in the Humberhead Levels Enb orn e
Con way
Fla dbu ry
Altc ar
Association
Adv ent ure rs’*
Lon gmo ss
Function Hydrological functions Flood water detention Groundwater recharge Groundwater discharge Sediment retention
Biogeochemical functions
H P P P
H P P P
H P P P
H P P P
U U P U
U P U U
Nutrient retention (N and P) Nutrient export In situ carbon retention
H H P
H H P
H H P
H H P
P P P
P P P
Ecosystem maintenance Food web support
H H
H H
H H
H H
P P
P P
Ecological functions
H – high potential; P – potential; U - unlikely * Where undrained or drainage ineffective
Table 9 Potential functioning of presently degraded (restorable and non-restorable) wetlands of the Humberhead Levels Do wn holl and *
Mi Ro Bla Bro Fog Bla del mn ckt ckh gat ck ney ey oft urs hor wo * t pe od
Eve Isle Ses Wi rin ha say gto gha m n m Mo or
Flood water detention Groundwater recharge Groundwater discharge Sediment retention
U U P U
U U P U
U U P U
U U P U
U U P U
U U P U
U U P U
U U P U
U U P U
U U P U
U U P U
Nutrient retention (N and P) Nutrient export In situ carbon retention
P P P
P P P
P P P
P P P
P P P
P P P
P P P
P P P
P P P
P P P
P P P
Ecosystem maintenance Food web support
P P
P P
P P
P P
P P
P P
P P
P P
P P
P P
P P
Association Function Hydrological functions
Biogeochemical functions Ecological functions
H – high potential; P – potential; U - unlikely * Where undrained or drainage ineffective
3.4 Opportunities for wetland regeneration There are various scales at which wetland restoration is technically possible. These include the result of major changes in land use policy, such as allowing water levels to rise in land currently drained by pump drainage. At the other end of the scale, there are opportunities for management of small patches of wetland in association with artificial features such as flood banks and within arterial ditch and dyke systems.
3.5 Mapping wetland functional units Though receipt of data in digital format for use with GIS had been delayed, plans were developed for provisional selection of 5x5km sample areas within the landscape sub-units indicated in Table 5. Small-scale wetland functional units identified in terms of soil types will be mapped using information from published soil maps (as far as can be negotiated within the HHL project),
supported by the most recent aerial photographs available, and where possible by field checking and local knowledge to confirm patterns and details of map separates. The most efficient means of achieving this would be to use information from soil maps published at 1:25,000 scale, which indicate detail such as field boundaries and ditches. Possible candidate areas for these studies, where detailed soil mapping exists at 1:25,000 scale, as shown in Table 10. Within the 5x5km blocks, (or elsewhere if necessary) sample areas will be chosen in consultation with local experts to include sites for detailed application of FAP (Stage 2). Table 10 Candidate 5x5km areas occurring on published soil maps OS sheet/quadrant
Location (area no.)
Landscape sub-area
Northern (1)
Marine flats
SE60/SE (Jarvis 1973)
Everton (5) and Thorne (6)
Valley peat, raised moss, outwash sands affected by groundwater
SK79/SW (Reeve and Thomasson 1981)
Everton (5)
Valley peat
SE73/SW (Furness and King 1978) SE63/SW (Furness and King 1978)
Northern (1)
Glacial lake, river flats
Wetland interest
Derwent Ings, drained claylands Ouse warp lands, subsidence areas of the Selby coalfield Raised bogs, fens along the River Torne, and wetlands of disturbed areas Fen and carr of the Idle Valley
3.6 Transfer of map information to a GIS The mapped information for each 5x5km square will be transferred to a GIS, using Arc View 3.1, which will require the purchase of the appropriate raster maps from the Ordnance Survey. The scale will be adequate to enable individual fields to be identified and consequent prescriptions for management to be capable of application on a field by field basis. Information will include the boundaries between wetland functional types and hydrological baseline information such as rivers, dykes and ditches.
4. VALUE IN WETNESS: THE ENVIRONMENTAL CAPITAL OF THE HUMBERHEAD LEVELS 4.1 Introduction
In this analysis, Environmental Capital Methodology (ECM) is preferred to methodologies like Cost Benefit Analysis (CBA1) and Contingent Valuation Method (CVM2) – whose aim is to address environmental assessment and management through economic valuation of nature (Pearce et al., 1989; Pearce, 1998). What these methodologies do is to measure human preferences for or against proposed changes in the environment – for instance the introduction of a new developement – in monetary terms. As many practitioners have observed, econometric techniques face difficulties when measuring nature’s values, and may fail to capture multidimensionality and passive use or non-use of the environment (Bishop and Romano, 1998). Such ‘uses’ of the environment represent a relevant part of human-nature relationships, and environmental appreciation may be difficult to include in a commodity-like logic (Prior, 1998). According to many scholars, monetary valuation of environmental functions fails to consider its
‘intrinsic’ values, which matter to individuals and go beyond the application of instrumental value via ‘willingness to pay’ (WTP) measures (Turner, 1995). Discourses of nature as capital are therefore criticised in terms of representitiveness: do they express a proper valuation of nature, dependent as they are on explicit economic estimation of the environment? (Foster, 1997) In addition, in the process of environmental deliberation an econometric-based approach may exclude the voices of those who do not have a direct interest in the decision, but whose knowledge and capacities can be valuable at the assessment stage (O’Neill, 1997). ECM aims to move forward from pure econometric valuation and from categorisations of the ‘natural capital’ as ‘critical’, ‘constant’ and ‘tradable’ (Countryside Commission et al., 1997). The philosophy of the ECM is that the environment can be considered as a set of characteristics and attributes, and not as a mere aggregation of things or objects. These environmental attributes, in turn, deliver a wide range of services, depending on the structural functions performed by the biophysical environment. ECM is therefore conceived as a way to describe the flow of benefits and services that the environment provides to stakeholders, and the level and sustainability of this flow according to the use being made of the environment. The ECM also takes into account the diversity of benefits that the environment provides to different typologies of stakeholders. These benefits can have a directly quantifiable economic value, and therefore satisfy an instrumental-utilitarian vision of nature, or be less easy to evaluate in numerical terms, and related intrinsic values that society perceives in the environment. For instance, a river valley can deliver a range of economic benefits like fishing, water for irrigation or agricultural production. On the other hand, other stakeholders may consider the same area of primary importance for recreation, nature conservation or for its aesthetical qualities.
The ECM approach is therefore adopted in this analysis because: has the capacity to assess the associations between environment and stakeholders according to their use of the environment, both from the social and economic point of view;is inclusive and works towards consensus building, as potentially can involve the full range of stakeholders at the stage of environmental assessment and include different kind of voices in the environmental assessment; refers to basic principles of sustainability of the environment and the related services delivered to stakeholders; has an holistic approach in identifying environmental attributes and services, describing the interrelationships among different environmental services and, ultimately, ecosystems; addresses the definition of the management profile, by determining quantity, scale of importance, trends, priorities of environmental attributes.
4.2 Main steps of the EMC approach The ECM is developed through the following steps (Figure 3): 4.2.1 Definition of the purpose of the exercise (step A) Devise the social and economic benefits of wetlands in the HHL context. These will be closely related to environmental benefits, a summary of which is given in 1.3, and are dependent on wetland functioning (2.4). 4.2.2 Dividing the Humberhead Levels area in distinct units (step B) Purpose of the analysis in this step is to divide the HHL into character areas, which are akin to small-scale landscape units (3.2). A character area is defined as one that contains one or more environmental attributes that give to that area a specific character. For instance, a character area may be represented by the presence of peat. The environmental service that the attribute peat delivers might be to sequester organic carbon or to protect water quality by acting as a buffer zone. This latter would deliver indirect economic benefits in making savings on the requirements for water purification. In contrast, direct economic benefits to the stakeholders would come from peat extraction and consequent trade, though depletion of a finite resource is not sustainable usage. According to the methodology, each identified character area holds one or more environmental characteristics, attributes or features that provide specific environmental services. The definition of environmental attributes and characteristics is made through a process of characterisation. This process is based on the following sources of information and inquiry: field work (in this case the information provided by WERG staff, both from a desk study and from site investigations); data assembly, at this stage the different sources of available data are collated in a GIS; spatial data representation is necessary to clearly identify and divide the HHL into character areas; operating at this level has not been possible, as digital data via FRCA has yet to be supplied. public perception studies allow to analyse how different social actors perceive the environment and their type of interaction. Analysis in this report is based on the transcripts of focus groups and interviews made by the Chamberlain Partnership’s (2000), within the report ‘Value in Wetness’.
Within the ECM, the purpose of public perception studies are: to explore the socio-economic implications associated with land use and environmental management; to define the stakeholders involved in the HHL environmental issues by including them in the process of environmental assessment; to provide the necessary information to define trends and targets of environmental attributes and services in the HHL (see step C).
Step A: Defining the purpose Step B: Defining character areas Step C: Identifying environmental attributes or services Step D: Evaluation Step E: Management Implications Step F: Monitoring Figure 3: Flowchart showing the main steps of the ECM approach (Countryside Commission et al., 1997). The scale of characterisation depends on the level of detail at which the analysis is performed. This is a key point in the HHL characterisation; in this analysis the choice has been to identify units at different spatial scales. Initially small-scale landscape units have been identified (3.2) within which more detailed functional assessment will be carried out in stage 2.Despite the risk of non-homogeneous characterisation, considering different scales within the same analysis widens the scope to explore the full range of the existing environmental services. The process of characterisation allows for the inclusion of different entities at a range of scales, which may correspond to specific physical features or may be represented by area wide characteristics that do not necessarily correspond to wider attributes, such as the intrinsic values of nature. For example, the unit of river alluvial flats is likely to include the following features:
natural and engineered river courses, riparian areas, dykes and ditches, wetlands, agricultural land (further characterisation can be done depending on land grade, land destination, soil type, land quality, etc.), hedgerows, woodland.
This same landscape unit can also provide wildness/isolation, tranquillity, integrity (anthropic vs. pristine), landscape distinctiveness or sense of place, presence of a significant ecosystem or group of ecosystems.
4.2.3 Identification of the environmental attributes and services for sustainability (step C) The aim of this step is to find out why the previously identified attributes matter for sustainability, by identifying the services that they perform. An environmental service can be defined according to different typologies, depending on the type of analysis being performed. Purpose of this step is also to establish links with the Functional Assessment Procedures, whose aim is to consider the range of functions performed by ecosystems. This is also relevant to the ECM, as some environmental services find correspondence with ecosystem functions. Examples of environmental services that have social and economic benefits are: flood prevention, reduction of water pollution like nutrient retention in buffer zones, environmental recreation, environmental education, landscape and cultural identity, sense of place, etc. 4.2.4 Evaluation (step D) The purpose of the evaluation is to examine whether enough of the previously identified attributes and services exist to meet the requirements of target objectives given identifiable trend parameters. Their importance and management requirements for sustainability are indicated by addressing the following questions: (i) (ii) (iii) (iv)
at what scale does the attribute or service matter; how important is the attribute within the identified scale; what is the trend in relation to the target that has to be achieved; what substitutions (if any) are possible;
(i) The scale at which the attribute matters refers to the geographical scale and not to the scale or dimensions of the attribute itself. For instance the small areal extension of the historical landscape of Thorne and Hatfield in the HHL has international importance. If an attribute appears to be important at different scales then it is likely to contain more than one attribute; in this case only the highest scale is considered. (ii) The importance of the attribute should be classified as high, medium or low and for each attribute justification should be provided. In general terms, this involves a certain degree of judgement about the attribute itself. Previous judgements are a valid support in limiting the subjectivity of the decision. The objectivity of this evaluation depends on the accuracy of the environmental assessment and the evidence provided. (iii) For each environmental attribute it is necessary to determine its target quantity and/or quality. The evaluation considers if the desired level of an attribute will be satisfactory after a specific time interval (the time during which the environmental management plan will develop). To achieve this, the following parameters have to be defined: CL, current level of an environmental service under examination, which can be determined in quantitative or qualitative terms, depending on the purpose of the assessment; TR, trend of the environmental service determined in relation to the current level CL, TR is therefore the rate at which CL varies over time; DL, the target for the environmental service, which the desired level of the service after a specific time interval. The determination of the target assumes renovation of natural resources and sustainability as leading principles. DL, which can be greater or less than CL, is determined in relation to the purpose of the assessment and the consequent management plan. For instance, according to specific purposes, the desired level of the service water quality can be represented by parameters like N concentration and turbidity, which in turn may determine the integrity of other environmental services like fisheries or drinkable water.
According to the definition of these parameters, for each of the environmental services examined, we can have three different scenarios: undershoot, overshoot and on target. The undershoot scenario (Figure 4) occurs when an environmental service has a trend that, with the existing environmental management practices, will not reach the desired level after a certain time. For instance, considering coarse fisheries, some of the HHL rivers are now showing improvements in water quality. If this were to remain unchanged, it would lead to a situation of undershoot, and the desired level of coarse fish required by some stakeholders would not be reached. Also on the question of water quality, without the introduction of buffer zones between agricultural land and the river system, the community has to sustain the direct and indirect costs of water pollution or the effects that high nitrate concentrations have on river bio-ecosystems. In addition, this also raises concerns for the intrinsic values of this environment and its preservation for future generations. If the present trend in water quality decline due to concentrations of nitrate and other pollutants, it is quite likely that the attribute will be unable to provide a satisfactory level of the service, when CL falls below DL. Within the ECM, this would produce an anticipated undershoot, which flags up the need for protective or enhancing management actions in order to preserve the attribute.
Level TR CL
DL
Time
Figure 4. Predicted undershoot condition, requiring defensive or protective management actions. The overshoot scenario (Figure 4) occurs when an environmental service has a trend that, with the existing environmental management practices, will reach and exceed the desired level after a certain time. Considering for instance riparian areas, where a desired target may be represented by an increase in habitat creation and biodiversity. These areas, if left unmanaged and without disturbance, will provide vegetation and increase wildlife the level of which will reach and even exceed DL after a given period of time. This is a condition of expected overshoot, as there will be abundance of the attribute; no defensive actions are therefore required (Figure 5).
Level TR CL
DL
Time
Figure 5. Predicted overshoot condition, ordinary management strategies are sufficient. Finally, the on target scenario is when the level of the environmental attribute and the desired level correspond after a given time as a consequence of the management actions undertaken. For instance, fisheries are an important environmental attribute of the HHL Ayre River. If the current level of commercial fishing is managed in order to maintain a certain level of fish population over time, after a certain time interval CL will correspond to DL , according to the existing trend. In this case the desired target is achieved, and no defensive actions are required (Figure 6). In this situation, the convergence of the level of environmental service on the desired target can start from a condition either of abundance (arrow above the x axis) or of scarceness (arrow under the y axis).
Level TR CL
DL
Time
Figure 6. Predicted on target condition, the existing management strategies are designed to satisfy the DL with the current service trend TR. (iv) After providing a full description of the attributes and related services present in the area, ECM considers the possibilities for substitution among environmental services. Substitution means the replacement of a loss in attribute or service by another that provides the equivalent benefits. The methodology depends on the scale on which it is applied and sometimes, if not directly related to the site of the investigation, be only possible in principle. For instance, we may consider that carbon sequestered within an intact peat bog is lost as carbon dioxide when the bog is drained and peat processed and used for horticultural purposes. This loss could be balanced if an equivalent amount of carbon were incorporated into actively growing peat, which would require peat soils currently drained for agricultural use to be allowed to rewet and peat growth re-initiated. This is likely to develop into some form of fen peat (as opposed to raised bog lost by cutting), but the balance in terms of environmental service (carbon sequestration) would be re-established. After discussing the ECM approach in its different steps, character areas, environmental attributes, services, scale of importance and substitutability are provided for the HHL area (Table 13).
Character/attributes
environmental attributes/service
benefits
Area between Howden (east) to Selby (west)
area from Howden (East) to Selby (west) and north of the M62 (same as above)
stakeholder involved
level of import.
capacity for economic supporting high value unsubsidised crops (potatoes, field vegetables, sugar beet) agricultural land economic (roots and brassicas are grown along river Ouse and combinable crops in the East)
scale of import.
trend
sbst
farmers
High
regional
undershoot, as a result of rising sea level trends and climate change
farmers and local communities
high
regional
economic
farmers
high
regional
social (increase of natural heritage within the environment), economic (ecosystem maintenance, food web support) economic
local communities
Medium ?
regional
slightly undershoot, n/a much of the area relies on gravity drainage which is becoming more difficult following changes in tidal flow in the Humber undershoot, as a result of n/a rising sea level trend and climate change difficult to determine, n/a undershoot no defensive action against mining subsidence is undertaken
farmers, landmanagers
High
regional
undershoot, due to sea level increase
n/a
cropping
economic
landmanagers
High
regional
n/a
cropping
economic
landmanagers
high
regional
on target, but irrigation and drainage needs to be met to maintain current status undershoot, if peat extraction continues at this rate will lead to increased flooding
grade 1,2 land, well drained sandy peaty soils along the ruver Humber Selby coalfields (sites affected by mining subsidence where wetlands have established)
capacity for supporting high value crops Increase of biodiversity, and habitat creation
Eastern area either side of the river Ouse and stretching down the river Trent land on and adjacent to the Isle of Axholme running down the river Trent to the east Fishlake area, north-east of Doncaster
high value crop production
n/a
n/a
Fishlake area, north-east peat extraction of Doncaster
economic
peat industry
medium
regional
Fishlake area, north-east cropping and agricultural land use of Doncaster
economic
farmers, landmanagers
medium
regional
Southern area stretching cropping and from Retford to agricultural Doncaster destinations
economic
farmers
High
regional
grade 3 land on clays with poor drainage in the area bounded by the M62 to the north and the M18 to the east and Doncaster as the Southern edge area from Retford (south) to Doncaster (north) areas along the river Idle areas nearby urban and commercial centres, etc.
arable land, livestock farming
economic
farmers
high
regional
arable production
economic
farmer
High
mineral extraction
economic
provides sites suitable for development, housing, horse paddocks commercial peat cutting
economic (employment, trade, provides new housing) economic
mining industry local community
peat NNR Hatfield, Crowle and Thorne Moors (ancient raised mires)
overshoot, if peat extraction continues at this rate, flooding is likely to occur, affecting other environmental services undershoot, if drainage scheme is not completed and all interested farmers participate to the scheme slightly undershoot, Doncaster town affects water abstraction by lowering water tables; maintaining irrigation supplies is a key issue in the area and River Idle is a main focus undershoot, the service is likely to diminish if the current insufficient drainage rate persists
n/a
regional
on target
n/a
medium
regional
overshoot,
n/a
medium
regional
difficult to determine with available data
n/a
land managers Medium ?
regional
overshoot
n/a
n/a n/a
n/a
NNR Hatfield, Crowle and Thorne areas, and specifically the moorland allotments at Thorne Cables Crowle Ribbon Row and Goole Fields NNR Hatfield, Crowle and Thorne areas, and specifically the moorland allotments at Thorne Cables Crowle Ribbon Row and Goole Fields Hatfield, Crowle and Thorne moors
sense of place, cultural identity
social
local communities
high
national
undershoot, commercial n/a peat cutting threatens this environmental heritage
historical landscape
social
national-inter national heritage
high
internatio nal
on target
n/a
wetland wildlife resource
biodiversity
internatio nal
undershoot if peat abstraction continues undermining conservation work
n/a
Hatfield, Crowle and Thorne moors
wetland wildlife resource
habitat creation
internatio nal
undershoot if peat abstraction continues undermining conservation work
n/a
active mining areas in Hatfield, Fishlake, Selby, Riccal
wetland creation
habitat creation, biodiversity
local high communities and conservationis ts, general public local high communities and conservationis ts, general public local Low? communities
regional and national
undershoot at the moment, but there is a real potential as the mining strips are subsiding. Creation of wetlands in these area will be possible if the Coal Authority and the Internal Drainage Board find an agreement
n/a
river floodplains
water capacity carriage
social and economic (if properly managed reduces the risk of damaging flooding events) social (place identity, sense of place of local community) and economic (tourism, environmental appreciation, recreation) economic
river floodplains
landscape
waterways
angling
waterways
historical landscape, landscape
social (place identity, cultural identity, archaeological and historical heritage), economic (env. appreciation, tourism)
waterways
habitat function (waterfowl, mammals, fish, etc.)
social and economic
rivers
fish breeding grounds social and economic
local communities
High
national
overshoot
n/a
local communities
high
regional
undershoot
n/a
national
undershoot
n/a
national
on target?
n/a
from local to internatio nal regional
on target?
n/a
undershoot
n/a
local medium communities, farmers, government (fishing license fee) local high communities, archaeological and palaeoecologi cal research, part of the national cultural heritage local high communities local high communities, local economy
Market Weighton Canal
fishing
economic
farmers
medium
local
ditches and/or dykes
remove surplus water, drainage functions (working waterways, as defined by landmanagers) increase of vegetation and fauna
economic
farmers, local communities
high
regional
social (added value to the environment, diversification of otherwise homogeneously managed landscape) economic (nutrient retention)
local communities
High
local communities
both social and economic (ecosystem maintenance, creation of new habitats, increase of biodiversity) social and economic
local communities
ditches and/or dykes
ditches and/or dykes
increase of vegetation and fauna
ditches and/or dykes
increase of vegetation and fauna
historic strip farming around Haxey, Belton and Epworth
historical landscape
Thorne Cables
historical landscape
social and economic
river system
coarse fishing
economic
undershoot, farmers believe that the increase in water level may represent the cause alongside bird predations on target?
n/a
regional
undershoot with the current agricultural practices (feasible only through incentives)
n/a
medium
regional
n/a
medium
regional
undershoot with the current agricultural practices (feasible only through incentives) undershoot with the current agricultural practices (feasible only through incentives)
national
on target?
n/a
national
on target?
n/a
regional
undershoot, increased cleanliness of water
n/a
local high communities, local-regional economy local high communities, local-regional economy local economy low
n/a
n/a
gravel and sand pits
coarse fishing
river banks
wildlife
river banks
bankside vegetation
social (biodiversity, environmental appreciation, landscape)
Riparian areas
buffer zones, denitrification
Riparian areas
water retention
Riparian areas Humber/Trent banks lakes reclaimed from gravel workings Ouse floodplain moor and peatland sites
local economy medium
regional
local community local community
high
local
high
regional
economic (water quality) and social (environmental justice, environmental quality) economic (flood prevention) and social (environmental risk)
local community
High
regional
local community
high
regional
ground water recharge and discharge Habitat creation
economic
local community
high
regional
Socio-economic
Local communities
high
Regional
very clean water
economic (tourism) economic
medium
local
farmers
high
regional
local communities and farmers
medium
regional
agricultural (roots and brassicas) wildlife tourism, environmental appreciation
economic
economic and social
undershoot, the sites are n/a not currently performing this service but there is the potential to meet such demand on target n/a not possible to determine at regional level, may vary according to the local condition (stock overgrazing or rank and overgrown if stock has been withdrawn) undershoot
n/a
undershoot, reintroduction of wetlands and vegetation in these areas should increase the level of the service undershoot, ditto
n/a
n/a
n/a
Undershoot, but outlined n/a as a potential opportunity in an Environment Agency report undershoot, service not n/a developed at the moment on target n/a undershoot, is only potential at the moment
n/a n/a
Isle of Axholme
tourism and recreation
economic and social
local communities
high
regional
undershoot, tourism has to promoted to reach the target
n/a
5. THE ENVIRONMENTAL CAPITAL AND WETLAND FUNCTIONAL ASSESSMENT
METHODOLOGIES
5.1 Background The ECM identifies benefits and services contained within the concept of sustainable development. Similarly FAP addresses the functioning of a wetland system by assessing those properties (controlling variables) on which functioning is dependent. A functional approach enables both potential functioning, through application of the functional classification (2.8), and actual functioning, using FAP, to be assessed, and consequently the constraints identified which preclude optimal delivery of what are identified as important functions. While the ECM considers a wide range attributes from natural systems to the build environment, but with the capability of delivering environmental benefits, FAP has been developed specifically for the assessment of wetland ecosystem functioning, though it does enable the significance of artificial features to be taken into consideration; indeed, the impact of such features can be critical to the delivery of some functions. For example, embankments are constructed to impound water in wastewater treatment systems thereby allowing purification processes to take place Similarly structures such as field boundary banks on floodplains can detain overbank flooding, allowing sediment deposition to take place and detaining water thereby reducing flood peaks downstream.
5.2 Benefits of the approaches The ECM identifies four distinct benefits (CAG 1997), each of which is considered below in terms of the FAP methodology. Integration
This refers to the capability of a scheme to embrace multiple benefits or services which require different management regimes. FAP allows a range of functions to be assessed which may not operate mutually at an optimal level. For example, a wetland may operate as a buffer zone by processing nutrient-rich waters flowing through it, but if valuable plant communities of conservation interest, adapted to low-nutrient conditions, are present, then they are likely to be lost or degraded through eutriphication. Application of FAP allows better-informed decisions to be made when alternative options are available. Subtler response
FAP could contribute to the ‘profile’ of management implications developed for a particular area of interest. Enhancement
In wetlands FAP can be used to help identify the desired level of an attribute identified by the ECM, and from a knowledge of the controlling variables in operation, the means of enhancement required to meet target objectives can be identified, for example raising water levels or adjusting flooding regimes. Characterisation
FAP can provide the means to identify and assess wetland functions. The level to which this operates depends upon factors such as scale, data availability and resources available (2.8) and can vary from potential functioning to different degrees of certainty about actual functioning.
5.3 Opportunities for the use of FAP within steps of the ECM The linkage between the environmental capital and wetland functional assessment methodologies is summarised in Table 11. More detailed assessments of this will be made during the field-based investigations of Stage 2
Table 11 Comparison of the step required to carry out the Environmental Capital and Functional Assessment Procedures Environmental Capital
Wetland Functional Assessment
Main sections
Steps
Main sections
Steps
Introduction
Defining the purpose
Introduction
Data collection
Defining the character
Database establishment
Selection of functions to assess Defining assessment area
Identifying environmental attributes and services
Evaluation
Interpretation
Evaluate each sustainability attribute or service Identifying management implications
Functional assessment
Collecting desk information Delineating HGMUs Characterising each HGMU Assessing each required function
Optional economic valuation
Assessing overall functioning Application of economic valuation techniques
Establishment of overall management profile Monitoring
Defining contributory area
Calculation of total economic value Application of results by users
In the following section reference should be made to Table 11, which lists the steps of both ECM and FAP approaches. Step A - defining the purpose
ECM includes defining the objectives and the spatial areas to be assessed. At this stage it is possible to identify the likely importance of wetlands within the area. This is likely to vary considerably from those of major importance, such as the Humberhead Levels or upland catchments to those with little or no wetland component, such as the built environment. FAP requires the identification of both the area to be assessed (assessment area) and the surrounding land (contributory area) capable of generating impacts likely to affect functioning such as nutrient-rich run-off from agricultural land causing diffuse pollution. The extent of the area of interest is also likely to determine the level of assessment and strategy of approach, depending on the resources available. For extensive areas such as the Humberhead Levels, it would be too time-consuming to carry out FAP in detail for the whole area; rather it requires a strategy of identifying broad functional units at the landscape scale, followed by more detailed assessments carried out in small areas of each
functional unit with a final stage of extrapolation to determine overall functional capability. In small discrete areas such as individual nature reserves or where some form of impact assessment is required for planning purposes, a more detailed approach of the full FAP could be taken to the whole area. Step B - defining the character The ECM requires those features to be identified which give the area its character. At this stage FAP requires the separation of a wetland into distinctive areas (functional units) within each of which functional assessment is carried out. These units are referred to as hydrogeomorphic units (HGMUs) because they are identified by features of landform (eg slopes, elevations, depressions) and hydrology (eg inflows and outflows of surface water). Where the full FAP is carried out, units with dimensions as small as only several metres can be mapped (eg micro-relief features on floodplains). Assessments at wider, perhaps catchment scales requires the identification of larger ‘compound HGMUs’, within which important features critical to wetland functioning are known commonly to occur. Step C Identifying environmental attributes or services The ECM seeks to say why the features identified in Step B are important for sustainability by identifying the attributes and services they provide for society. FAP identifies wetland functions capable of delivering environmental benefits. In the case of river marginal wetlands, functions are shown in Table 2, which also identifies the processes controlling the functions. In turn functions provide goods, services and attributes, which can have value to society. These relationships are illustrated in Figure 1. Functions can be linked to key features of the area and can support the case for their protection and conservation. Step D Evaluation This stage could usefully incorporate FAP to help answer the key questions needing to be addressed: i) What is the scale of importance? Key issues are the size, pattern and management of wetlands, together with their condition or status (Table 1), which can determine how effectively they function. ii) How important is the attribute or service at this scale? Th likelihood of functions being performed (or their potential) helps to assess this. iii) What is the trend relative to the target? The degree to which functioning is being performed and the possibilities for optimising functioning could be important in achieving target objectives. iv) What (if any) substitutions are possible? The functional assessment of a range of HGMUs would allow candidate substitutions of environmental benefits to be identified (see example in 4.2.4). Step E Management implications An assessment of wetland functioning (potential and/or actual) makes an important contribution to the information on which management decisions are based. For this purpose, it could be useful to have an assessment both of overall functioning and of individual functions identified as being of particular importance within an area of interest. Step F Monitoring There is a requirement to monitor the sustainability of environmental capital over time. For areas with an important wetland component, this should include a strategy for monitoring wetland
environmental parameters such as water regime or water quality. This could vary from long-term and/or continuous monitoring using purposely-installed equipment to short-term field campaigns to measure key processes.
6. FUTURE ACTIONS 6.1 Work in Stage 2 The work of stage 1 has identified the important landscape units which form the context for a landscape-scale approach to assessing wetland functional resources for the Humberhead Levels. In addition small-scale soil-based wetland functional units have been identified and their potential functioning determined. The next stage will involve detailed site-specific wetland functional assessment to be undertaken within small-scale units at locations representing the main landscape types. These locations are to be decided following consultation with the Countryside Agency and taking into consideration factors such as access agreement and regard to co-ordination with other related initiatives within Value in Wetness, where mutual benefit may be obtained. At the time of finalising this report, GIS data had just been made available, but too late for inclusion until Stage 2. It would now be useful if detailed soil information from published surveys were made available in digital form from the areas identified in 3.5, which could then form the basis for HGMU mapping and subsequent wetland functional assessment.
6.2 Integration of wetland issues
The Chamberlain Partnership Report (2000) identifies a series of options for sustainable land management relevant to the Humberhead Levels, based on those identified by the government and the Countryside Agency. These are seen as forming a framework, within which local objectives can be formulated, discussed and integrated under the topic areas of biodiversity, history, farming and socio-economics. In practice this is seen as possible by means of a series of projects. The report recommends 21 new actions under the broad topics of agricultural water resources, rivers and fisheries, tourism and access, and environment and heritage (summarised in the summer 2000 edition of ‘On the Level’). The table below identifies the main points which include wetland issues, which it will be important to bear in mind when developing projects. 1. Establish clear target for conservation. Targets should take into account factors such as original likely extent of
various wetland types and other potential benefits to be derived from restoration (beyond wildlife conservation). 2. Segregate the causes of water problems. There is a need to identify the kinds of problems and likely impacts on wetland functioning (eg water quality regulation) 3. Environmentalists to present a united front. Need to promote the full range of environmental (and socio-economic) benefits to stakeholders 4. Encourage Water level Management Plans. Explain benefits (as above) 7. Encourage positive water level management. Should demonstrate the benefits of wetland functioning such as in buffer zones 8. Broad water management remit for IDBs. Ensure IDBs understand the range of potential environmental benefits delivered by wetlands. 11. Promote integrated management of river/dyke banks. Investigate opportunities for buffer zones 12. Assess the potential for remodelling river channels. Also consider buffer zones 13. Promote angling. Promote the link between fisheries and wetland conservation. 15. Promote wetland habitat creation. Stress the wider environmental benefits than just wildlife conservation 17. Reward farmers for delivering environmental gain. Use wetland functional assessment and economic valuation to demonstrate wetland values. 18. Set up studies to compare gravity and pump drainage. Determine implications for wetland functioning 19. Encourage land purchase by environmental groups. Demonstrate wider benefits than wildlife conservation. 20. Develop projects. Include functional assessment where appropriate. 21. Develop mechanisms for information transfer. Include wetland functioning and benefits
6.3 Development of FAP As new methodologies for environmental assessment are developed for specific purposes, it is useful to consider their potential for wider application. In this context, the parallel development of the ECM and FAP have been discussed in section 5. In practical terms it is necessary to develop protocols which can be tested in a variety of situations to determine their accuracy and applicability. As described in section 2.5, research is still being carried out to enable FAP to be applied at the catchment scale, and versions for other types of wetland ecosystem are still under development. Work to date has focused on river marginal wetlands with recent studies identifying the modifications required to cater for lake marginal and estuarine wetlands. Part of the development of FAP is investigated possible techniques for economic valuation of functioning. The Value in Wetness initiative is the kind in which options for such methodologies can be assessed. A further useful step would be to develop protocols for their application at a range of scales within other areas such as those of the Land Management Initiatives.
6.4 Strategy for wetland conservation The overall approach to optimising the protection and conservation of the wetland resource and its functioning in the Humberhead Levels could parallel the structure of a national wetland strategy devised by Denny (1994), in which six steps are identified as shown in Table 13. The current project effectively covers steps 1-4, and results within Value in Wetness will unpin future decisions on policy development and management covered by steps 5 and 6.
Table 13 A strategy for wetland conservation in the Humberhead Levels Step Description 1
Precautionary Principle
2
Wetland Classification
3 4
Wetland inventory Environmental capital index
4/1 4/2 4/3 5
Natural capital stock Natural exploitable stock Natural replaceable stock Formulation of wetlands conservation strategy Formulation of wetland management plans
6
Parallel application for Value in Wetness
Assess the wetland resource, present and potential functional benefits and threats Define wetlands and their status Produce wetland inventory Carry out assessment of functions and environmental capital on selected wetlands Intact wetlands Degraded restorable and non-restorable wetlands Destroyed but no equivalent replacement strategy Development of a wetland conservation and protection strategy within Value in Wetness Management plans for designated sites; elsewhere include within best management practice on farms
REFERENCES Bishop, R.C. and Romano, D. (1998) Environmental resource valuation: application of
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1 CBA is a way to measure the net flow of benefits from the natural environment to human beings by treating its resources and functional capacities as a form of capital stock or ‘natural capital’. 2 CVM seeks to evaluate environment and nonmarket goods and services by asking individuals about their values through surveys methods. On the basis of a prepared scenario, which describes the attribute of the questioned environmental good or service, respondents are to decide how much they would willing to pay for it. The surveys gather respondents´ values in relation to the ’prepared’ scenario (Bishop and Romano, 1998).
