Research Article Issues in GIS development: adapting to research and ...

int. j. geographical information science, 1998 , vol. 12 , no. 5 , 465 ± 478

Research Article Issues in GIS development: adapting to research and policy-needs for managem ent of wet grasslands in an Environmentally Sensitive Area 1

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N. J. BROWN , R. D. SWETNAM , J. R. TREWEEK , 1 2 1 J. O. MOUNTFORD , R. W. G. CALDOW , S. J. MANCHESTER , 1 3 4 T. R. STAMP , D. J. G. GOWING , D. R. SOLOMAN 4 and A. C. ARMSTRONG 1

NERC Institute of Terrestrial Ecology, Monks Wood, Abbots Ripton, Huntingdon, PE17 2LS, UK 2 NERC Institute of Terrestrial Ecology, Furzebrook, Wareham, Dorset BH20 5AS, UK 3 Silsoe College, University of Cran® eld, Silsoe, Bedford, MK45 4DT, UK 4 ADAS Land Research Centre, Gleadthorpe, Meden Vale, Mans® eld, NG20 9PF, UK ( Received 18 June 1997; accepted 30 September 1997 ) Geographical Information Systems (GIS) represent a rapidly changing technology, and awareness of their capabilities outside the GIS arena has grown rapidly during the last few years. As part of a wide-ranging ecological research programme on wetlands in Environmentally Sensitive Areas ( ESAs) the Institute of Terrestrial Ecology (ITE) developed a GIS for the examination of lowland wet grassland landscapes, and the potential for their restoration (the `Wetlands GIS’). A ¯ exible approach to the development of the GIS was necessary to accommodate changes in technology and in the needs and interests of the key `stakeholders’ in the project: the research ecologists who supplied much of the data for the GIS and the policy-makers concerned with the application of research ® ndings to land-management problems. This paper explains the rationale behind the use of GIS in the context of ESA-management and its evolution over a three year period. Examples of output are used to demonstrate the bene® ts of map displays for encouraging communication between developers and users, the data-storage, handling and analytical capabilities of the GIS and its role in matching the needs of researchers and policy-makers. Abstract.

1. Restoration of wetlands: policy requirements

In lowland Europe, many wetland communities evolved as an integral component of farmed landscapes. Under some traditional systems of agricultural management, farmed wetlands sustained a high wildlife value, but intensi® cation of farming and the associated increased drainage has eroded this ( Ratcli e 1984). In an attempt to arrest the decline, and to encourage integrated management of land for agriculture, amenity and nature conservation, the Ministry of Agriculture, Fisheries and Food (MAFF) introduced the Environmentally Sensitive Area ( ESA) scheme to the United Kingdom. A desk study was carried out for MAFF by a consortium of the Institute of Terrestrial Ecology ( ITE), the Agricultural Development and Advisory Service (ADAS), Soil and Water Research Centre (SWRC) and the Cambridge University 1365± 8816/98 $12´00

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Department of Land Economy. This study demonstrated the potential for successful combination of agricultural and ecological objectives in preserving, enhancing and restoring the wildlife value of wetland habitats. The study identi® ed a number of areas in which further ® eld and experimental studies were needed ( Treweek et al . 1991 ), identi® ed possible ecological objectives for wetland restoration programmes and reviewed the technical and socio-economic factors which in¯ uence successful implementation ( Treweek et al . 1993). It is self evident that reinstatement of suitable hydrological conditions was an important pre-requisite for the restoration of wet grasslands. In those ESAs which include signi® cant areas of lowland wet grassland, a range of water management operations has been prescribed to create appropriate hydrological regimes for those wetland communities targeted for conservation ( Treweek et al. 1995). Research scientists and the Ministry realized that it was critical to be able to evaluate the e ectiveness of these di erent water management operations for achieving ecological objectives and ensuring viable agricultural production on a range of soil types. Farmers and conservationists have a range of needs and questions requiring attention: Conservationists Do current hydrological conditions pose a threat for important wet grassland species? Which species are most at risk and in what way? Are these species unique to this area? Which other aspects of farming also pose a threat to these species? Does restoration of wet grassland biodiversity demand hydrological change? What areas of land are available for restoration? Farmers What areas of land would be eligible for ESA tier payments with little intervention or management change? How much would ESA payments amount to if all available land was restored? If hydrological conditions altered what are the implications for agricultural production? E

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2. Restoration of wetlands: research needs

Earlier studies concluded that e ective hydrological management either for wetland restoration or for e ective farming would rarely be possible on a `® eld-by-® eld’ basis ( Treweek et al . 1991 ). Manipulation of water-levels in one ® eld can have signi® cant e ects on hydrological conditions in adjacent ® elds. With increasing demands for water from domestic and industrial users, the ability to achieve target `wetness regimes’ on one site might depend on water management throughout whole catchments. Similarly, several of the ecological implications of di erent water management regimes could not be simply predicted or assessed in relation to individual sites. Many waders and wildfowl, for example, make use of a wide variety of sites to satisfy their breeding requirements through the year. Although the water-regime needs of individual species or communities are appropriately studied through controlled experimentation in the laboratory or in the ® eld, the results of such research cannot be applied without some attention to the spatial patterns of the environment. Conditions for a target species may be entirely suitable at a point, but this species may neither colonize nor, if present, survive in the longterm unless certain elements in the landscape are present. For example, an appropriate

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water-regime for species-rich wet grassland may be created in a ® eld, but the arrival of propagules by wind or water might be prevented by the presence of shelter belts or the absence of a suitable seed-source upstream. In the particular case of mobile organisms such as birds or mammals, a matrix of habitat types may need to be present before a site is suitable ( Forman & Godron 1986). Although birds and mammals may be physically capable of crossing roads or open arable land, these landscape elements may function as barriers, either because the animal is exposed to predators, or to road and farm tra c. The impact of landscape change on all the elements in the habitat mosaic must be determined. Catchment-wide water management may be the most e ective way of achieving particular results for conservation and agriculture, but the implications of such action for non-target communities and activities needs to be assessed. Ecological research must eventually address the total environment in which a species or a community functions, and the study of spatial pattern and process is fundamental to such work. 3. The applicability of GIS to research and decision making

At the outset of the research in 1993, it was realized that a Geographical Information System (GIS) would be the appropriate vehicle for integrating data sets and maps on agriculture, ecology, and hydrology, and for subsequent analysis and interrogation of the data. Many of these functions could also be achieved through the use of other types of software, such as statistical analysis packages. However, when the technical requirements (such as data storage, modelling and, in particular, the need for spatial analysis) were considered , GIS was clearly the most appropriate system. 4. The applicability of GIS to the ecologica l exam ination of wetlands

Management of land for multiple objectives (in our case agronomic, ecological and economic) requires strategies based on a thorough understanding of the mechanisms which determine the likely outcomes of di erent management options. The aims of the approach adopted within the present research programme were two-fold: E

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to assess links between the distributions of wetland communities, hydrological regime and agricultural management; and to provide a mechanism for predicting the likely implications of alternative water management actions for both agricultural and ecological interest within de® ned test catchments.

For the research described here, GIS o ered improvements over manual mapping approaches in the areas of data organization and management. It also o ered the opportunity for description and modelling of spatial relationships. For the system developed, it was possible to build a comprehensive set of map-based digital data, with signi® cant quality control. Since the aim of the work was to investigate realistic water management scenarios, `catchments’ were de® ned in terms of the scope for coherent hydrological management, rather than conventionally in terms of the limits of watersheds. The ® rst phase of the work involved the identi® cation of suitable study areas ( Treweek et al . 1994). Four areas were chosen, located in three ESAs: the Upper Thames Tributaries ( River Ray), the Somerset Levels and Moors ( West Sedgemoor and Southlake Moor) and

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the Broads of Eastern England ( Halvergate marshes). This paper focuses on the River Ray site, although all four are included within the Wetlands GIS . 2 The Ray study area covers approximately 35 km around Marsh Gibbon, near Bicester on the borders of Buckinghamshire and Oxfordshire ( Treweek et al. 1993 ). Wetland restoration initiatives began here under the auspices of a Countryside Stewardship Scheme (CSS) in 1991, and continued with the site’s inclusion in the ESA. The catchment of the Ray includes three tributaries draining the Oxford clay vale and uplands, with a restricted outlet near Lower Arncott, leading to frequent ¯ ooding in the area south of Marsh Gibbon. The soils are dominated by the Fladbury and the Denchworth series, both clay soils, strongly gleyed, and highly impermeable. The prevalence of ¯ ooding and poor drainage led to the survival of extensive wet grassland, especially close to the river itself. Modern sub soil drainage has allowed a considerable area of slightly higher-lying land to be converted to arable agriculture, though ESA, CSS and set-aside have stimulated some reversion to grassland in the 1990s. From a nature conservation perspective, the Ray study area provides a valuable area of Meadow Foxtail± Greater Burnet ¯ ood meadow, technically Alopecurus pratensis± Sanguisorba o cinalis grassland, MG4 of the National Vegetation Classi® cation ( Rodwell 1992), as well as smaller areas of other grassland types. 5. The ability of the GIS to deliver useful output

Monitoring and organizing attributes associated with spatial location and time are key elements of most GIS. However, a further important objective of the present research programme was to develop methods for modelling the implications for ecological diversity and agricultural opportunity of water management regimes within discrete catchments. These considerations applied to the development of the W etlands GIS , since `GIS should be capable of shipping data to analytical models used by ecologists, biologists and natural resource managers, and then re-importing the model outputs for display as maps, tables or graphs’ ( Dangermond 1989 ). Even for a relatively small study area like the Ray, it may be impractical to gather data from all parts, and potential problems arise due to incomplete coverage of the data available. However, as Davis et al. ( 1990) state ìt is our opinion that it is unrealistic to postpone action on preserving biodiversity until complete information is collected. Rather we must make e ective use of what we already know, while systematically organizing and expanding our knowledge base.’ In situations such as those found in the River Ray study site, irregular ® eld boundaries on the source maps, together with the need to model linear features along those boundaries, required that the data handling be done with a full vector GIS. It was also recognized that some of the complex overlay and regression analyses required if the Wetlands GIS was to ful® l all the objectives set out by the researchers would probably be best achieved using raster-based mapping techniques. After detailed evaluation of these requirements, and of the systems available to the ITE, the ARC / Info GIS was selected as the most suitable system. 6. Aspects of the development of the Wetlands GIS

6.1. T he development of a user f riendly interface Given the substantial variety and quantity of data available, it was essential from the outset that a simpli® ed form of data management and access should be established to ensure e ciency in both data compilation and linkage. Following discussions


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with the ecologists and hydrologists, it was also clear that there would be a need to explore and analyse the data rigorously. Third, it would be necessary, at various stages of the project, to report and demonstrate the progress of the work to the policy customers in MAFF. As emphasized by Davis et al. ( 1990) Àn important initial phase in the design of an information system is to identify that set of users to be supported and to assess their information need’s. Developing an e ective user interface can greatly enhance access to data and therefore utility of a GIS. An important feature of the Wetlands GIS development was therefore the deliberate design of an interface which would make the product accessible to the non-GIS specialist user. The W etlands GIS needed to access modelling routines designed and constructed externally by hydrologists (Armstrong 1993). A key element of the Wetlands GIS was the establishment of links between the many ecological data sets and these hydrological models. The techniques used to couple models to GIS are well documented, the links being mainly in terms of model input and output (Steyaert & Goodchild 1994). Published examples of successful coupling of ARC / Info include links to an àgricultural non-point-source pollution model’ ( Needham et al. 1989 ), and a forest growth model ( Polzer et al . 1991, Urban 1990). Extensive discussions amongst the project team for the present study resulted in a highly structured GIS design. A schematic diagram (® gure 1 ) shows the logical links that were required within the W etlands GIS to enable the full range of map/ data analyses to be carried out, including not only individual data sets but also the interrelationships between them. Such a range of potentially complex procedures required lengthy commands to perform map composition and database queries, but these commands were hidden behind a menu interface. Base maps for each of the four sites formed the core data within the Wetlands GIS . All information was related to these site maps, and the digital versions were derived from varying sources. For the River Ray, colour aerial photography (® gure 2) of the site was used to interpret the land-use in detail and produce digital boundaries. This process included the ortho-correction of the aerial photography. These boundaries were imported directly into the GIS. This method of map acquisition was highly accurate, with the added advantage of being tailored to the requirements of the

Figure 1.

Part of the initial design of the Wetlands GIS showing the database structure outline.

Figure 2.

Aerial photograph of part of the River Ray site.

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project. Nine land-use classes were interpreted from aerial photography, with seven sub-classes: ® eld boundaries, water-courses (stream/river, drainage channel ), woodland (coniferous, broadleaved, mixed ), scrubland, arable, grassland, ridge-and-furrow (arable, grassland), disturbed ground and wetland. 6.2. Data entry and management In constructing the Wetlands GIS two tasks had to be completed in parallel: the building of the database and the generation of maps for each of the study areas. Both of these elements evolved with the steady provision of new data. In addition to the base map of the Ray site, other maps were digitized at ITE Monks Wood from ® eld survey documents. The Wetlands GIS contains many data sets, and the range of material available di ered somewhat between study areas; a simpli® ed listing of the data for each of the four sites being provided in table 1. The data included maps of the di erent catchments, land-use maps and species information for individual ® elds, dipwell data for selected areas, bird distribution maps and ® eld management information. The data incorporated in the GIS had a number of di erent origins. Some were imported from other GIS, others were converted into GIS maps and databases from computer lists held in other computer systems. Consolidation of the large volume of data and their integration into the GIS proved major tasks. Much of the early e ort involved getting the various data sets into the Wetlands GIS in a suitable (that is consistent and compatible) form and subsequently carrying out a rigorous validation process. As Davis et al. (1990 ) also state: `data in a GIS database can be of no higher quality than the source material. Map errors, for instance, can propagate and multiply through overlay operations.’ Aspinall ( 1994 ) points out that error analysis ìs an important element of the method, and is integral to derivation, interpretation and use of the results of modelling’. To be able to exploit the full interactive power of the GIS, it was necessary to use a key `map object’ to link the structured information, held in the relational database, to the map information. As the majority of the data were recorded at the ® eld level, the ® eld number became this key object. All the species information could then be interrelated because each table of information was constructed around this ® eld number or identi® er. 6.3. Collection of ecological ® eld data for map display Data on the range and abundance of species are of fundamental importance for ecological studies. Abundance data are more di cult to collect than range data, since the former require more intensive sampling. As a result, such information is available only for the most thoroughly studied taxa ( Davis et al. 1990). Even though the ITE and its partners were able to collect numerous ® eld data, much of these applied to those groups most amenable to rapid survey particularly vascular plants and birds. Invertebrate groups were excluded from the data-gathering exercise, except for those (such as earthworm biomass) which could be recorded in a straightforward manner from soil samples. 6.4. V egetation composition A reconnaissance survey of the River Ray site was carried out in 1993. In 1994, as many grassland ® elds as possible were surveyed during the growing season. In 1995, a further survey revisited those included in the reconnaissance, and most of

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N. J. Brown et al. Table 1.

Wetlands GIS Ð

data inventory.

Ray

West Sedgemoor

Southlake Moor

Halvergate marshes

Field species lists: presence /absence 1994 Field species lists: presence /absence 1995 Quadrat data: species and % cover 1994 Quadrat data: species and % cover 1995 NVC results per ® eld NVC results per quadrat Ellenberg mN per ® eld Ellenberg mF per ® eld Quadrat point locations Ditches: plants

ITE

RSPB

ITE

ITE

ITE

N/A

N /A

ITE

ITE ITE ITE ITE ITE ITE ITE N/A

N/A N/A RSPB/ITE ITE ITE ITE N/A RSPB

ITE N /A ITE ITE ITE ITE N/A ITE

ITE N/A ITE ITE ITE ITE N /A N/A

Soils data

ITE

N/A

N/A

N /A

Botany

Zoology (includes environmental and food data gathered ancillary to major bird surveys)

Bird counts (monthly) 1992 Bird counts (monthly) 1993 Bird counts (monthly) 1994 Worm biomass (gm) Other invertebrate biomass Ditches: invertebrates Soil wetness Soil penetrability Vegetation Height

Hydrology (see also Management )

Dipwell information 1994 Modelled Hydro. Regime: Soil wetness 36 p.a Soil moisture 36 p.a. Soil ¯ ooding 36 p.a Wetness Index Drought Index Recorded days ¯ ooding Drainage Status

M anagement

Land use ESA payments / Tier status Grazing Livestock units Fertilizers Slurry or manure applied Flooding susceptibility

Geographical

Field boundaries Rivers

ITE ITE ITE ITE ITE N /A ITE ITE ITE

RSPB RSPB RSPB N /A N/A RSPB RSPB N/A N /A

ITE ITE ITE ITE ITE ITE ITE ITE ITE

RSPB RSPB RSPB N/A N/A N /A N/A N/A N/A

ADAS

RSPB

ADAS

ADAS

ADAS ADAS ADAS N/A N/A N/A ITE

N/A N/A N/A N/A N/A N /A RSPB

ADAS ADAS ADAS ADAS ADAS N/A N/A

ADAS N/A N/A N/A N/A RSPB ADAS

ITE ITE ITE ITE ITE ITE ITE

RSPB RSPB RSPB RSPB RSPB RSPB RSPB

ITE EN/ADAS EN EN EN EN N /A

ADAS ADAS N/A N/A N/A N/A N/A

ITE ITE

ITE N/A

ITE N/A

ADAS ADAS

the remaining grass ® elds to give an overall total in excess of 220 surveyed ® elds. Only intensively managed grass and newly-sown leys were excluded. In each ® eld a list was prepared of all the vascular plants and Bryophyta observed. Vegetation


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composition was assessed in 5Ö 1 m quadrats. In each quadrat all vascular plant and bryophyte species were recorded, with an estimate made of the percentage cover of each species. A total of 197 species of vascular plant and 8 bryophytes were seen in the grass ® elds in 1993± 95. From this survey information, three data sets were created within the Wetlands GIS : 1. species presence /absence; 2. individual quadrat lists; 3. mean percentage cover of each species in each ® eld. To these ® eld data summary information on the known ecological requirements of particular species were added, using a system of indicator values developed by Ellenberg ( 1988). Hence a data-base was created containing the moisture ( F) and fertility (N ) indicator values for all the species recorded in the study areas. 6.5. Ornithologic al survey All ornithological data from the Ray area were gathered by the ITE. Three years of data are available covering over-wintering birds and breeding birds (Caldow & Pearson 1995 ). The W etlands GIS contains counts of birds in ® elds from October through to June. Associated information was collected on the ® eld characteristics and the invertebrate food-source available: soil penetrability, soil wetness, invertebrate biomass, worm biomass and sward height at the time of survey. 7. An exam ple analysi s

The use of the menus in the W etlands GIS is best illustrated through an example which explains how maps and data may be interrogated. This particular example demonstrates how the user is able to move through the routines in various ways, selecting di erent items of interest, initiating various analytical functions, and displaying mapped results. In lowland wet grassland, waders and wildfowl are key bird groups, and in the River Ray area snipe and lapwing are of particular interest (Avery et al. 1995 ). The foraging ecology of these two waders di ers, and they require slightly di erent habitat conditions for success. Query 1: W hich ® elds are used consistently by lapw ing and snipe within the River Ray study area?

Steps involved: E

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From the main menu of each site, enter the Ecological Query Menu which then gives access to the BIRDS menu for the R. Ray site. Access the BIRDS database for the site and ® nd all those ® elds which were used consistently by snipe and lapwing. Display the maps of the species distributions.

For the purposes of this example query, ® elds were classi® ed as being `consistently’ used if birds were present in at least two winters during the study period of three study years. Figure 3 gives an immediate impression of the range of these two species. The maps suggest that the two distributions tend to be mutually exclusive, though both birds apparently favour river-side ® elds. The reasons for these distributions may be investigated through the relational database containing the characteristics of those ® elds used by snipe and lapwing (table 2). Lapwing use fewer ® elds than

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Figure 3.

River Ray: ® elds used consistently by the lapwing and the snipe in the Ray catchment.

Table 2.

Land-use of ® elds used consistently by lapwings and snipe, River Ray ( Bucks and Oxon).

Bird species Lapwing Snipe

Land use C.S.S * Winter wheat Unimproved grass C.S.S* Set-aside Nature reserve Unimproved grass Winter wheat

Total Ha. in the bird survey area

Total Ha. used by birds

% of all used ® elds

No. of ® elds used

Mean size of bird ® elds

94´4 28´6 92´0 94´4 23´7 7´3 92´0 28´6

37´8 7´1 10´0 29´3 12´5 7´3 10´8 7´1

40´1 24´7 10´9 31´0 52´9 100´0 11´8 24´7

4 1 1 4 3 2 1 1

9´5 7´1 10´0 7´3 4´2 3´6 10´8 7´1

*CSS = Countryside Stewardship Scheme.

snipe but both species make disproportionate use of ® elds entered for the Countryside Stewardship Scheme, with snipe also favouring set-aside ® elds. Query 2: Do the ® elds used consistently over the study period di er in terms of soil wetness or food availability?

Preliminary examination of the habitat preferences of snipe and lapwing in the River Ray suggested that snipe occurred more frequently in wetter ® elds rich in invertebrates, whereas lapwing tolerated ® elds with a low abundance of invertebrates ( Treweek et al . 1994, Caldow and Pearson 1995). To examine these patterns further the invertebrate information for the ® elds used by snipe were accessed and queried within the BIRDS menu of the GIS. By choosing the `query a ® eld’ option the ® elds favoured by the snipe could be examined in greater detail (® gure 4). Soil information on penetrability, wetness and invertebrate biomass were examined. Recorded values for soil penetrability in the River Ray ® elds ranged from 0´0 to 9´01 with an average of 4´9 (measured in KgF), higher values indicating that greater force is necessary to penetrate the soil surface. The identi® cation box portrayed in ® gure 4 shows that ® eld 133 had a relatively low penetrability value i.e. the soil was


Figure 4.

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A typical group of menu’s from the Wetlands GIS snipe ® eld details.

comparatively soft. In the study area, soil wetness values ranged from 0´0 to 4´2, in a standard scale where 0 is dry and 4± 5 is very wet. The biomass of soil fauna (earthworms and other invertebrates) was measured in terms of live weight in ten randomly-located 10 Ö 10 cm soil cores. Mean values for individual ® elds ranged from 0´0± 13´4 g for worms and 0´0± 24´4 g for other invertebrates. Field 133 had average wetness but a high biomass of soil fauna, providing a comparatively rich food source ( ® gure 4 ). The ® elds favoured by lapwing, rather than snipe, are those (e.g. # 140 ) which were drier ( 1´5), with hard soil ( 7´27 KgF required to penetrate the surface) and impoverished food resources. Easy soil penetrability may not be as important for lapwings since they are near surface feeders (re¯ ected in their bill morphology), in contrast to snipe which rely upon an ability to probe deeply into the soil. The procedure followed for one study site may be repeated for the remaining three, enabling the consistency of the relationships revealed for the River Ray to be tested. Use of the W etlands GIS provided strong support for the central in¯ uence of water-regime on the distribution of biota throughout the `test catchments’. The GIS

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permitted numerical estimates to be made of the preferences of a range of species and communities for particular water-regimes, and tier prescriptions. These results may be compared with those from related studies within the research programme, based on rigorous ® eld survey (Gowing and Spoor, in press) and controlled laboratory experiments (Mountford et al. 1996 ). The analysis described in this paper has not covered predictive modelling to any great extent. This issue, and, in particular, its potential use within the Wetlands GIS, is explored in some depth in a paper recently submitted to another journal (Swetnam et al. 1997). Taken together, survey, experiment, modelling and use of the Wetlands GIS should help re® ne the guidance given to all those with an interest in water management for nature conservation and viable agriculture. The implications of raising water-levels within any water management unit depend on many interrelated factors that operate at a range of scales. It will rarely be possible to achieve precisely the same conditions of wetness on all sites with potential for wetland restoration, and not all such sites will be equally suitable for colonization by wetland species. As a result, restoration strategies should be modi® ed to take account of inherent di erences between sites, both in terms of their restorability, and in terms of their likely contribution to ecological diversity. 8. Discussion

The W etlands GIS was developed to provide mechanisms for predicting the outcome of alternative water management actions for both agricultural and ecological interest. It was designed to provide a platform for the integration of base data sets and maps, linkages to models, and the subsequent analysis and interrogation of the data. GIS o ered signi® cant improvements over manual mapping approaches in the areas of data organization and management, as well as the opportunity for description and modelling of spatial relationships. The W etlands GIS will continue to provide ecologists with a valuable tool with which they can carry out ecological investigation that would not previously have been possible in a single system. Interaction between ecologists and GIS specialists will stimulate further evolution of the W etlands GIS , producing new analytical pathways. Such innovations should themselves not only foster hypotheses for testing, but also allow integrated approaches to landscape management. There remain concerns about the wider availability of the information it contains, and the output it produces, to people outside the ITE e.g. scientists, managers, planners and landowners. E ective communication of the results of research is vital if management decisions are to be improved. Many types of cartographic output can be generated from the GIS, most frequently in the form of screen displays of the results of speci® c analysis. The output may also take the form of hard copy for use in reports, or be saved as digital map displays (such as screen dumps) for insertion into other computer display packages such as desk-top mapping packages. Although the complete GIS has been successfully copied to a collaborating research body, and indeed is in operation there, it must be admitted that this organization has similar computing capability and expertise to those available at the ITE. Such a situation might not be the case should an attempt be made to widen the use of the Wetlands GIS . Use of the Wetlands GIS has helped structure research priorities, providing considerable scope for the generation of hypotheses, and their preliminary testing. In particular the GIS has helped focus the collaborating scientists on both spatial


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and temporal variation in water-regime, together with the corresponding responses of both wildlife communities and agricultural systems. The use of four varied lowland wetland sites in the W etlands GIS has allowed scientists and policy-makers to assess how closely environmental management prescriptions and particular plant communities and bird populations are related on di erent soil types, and in di erent landscape contexts. The W etlands GIS has also provided a means whereby the implications of land-use policy may be predicted with potential to identify con¯ icts between policy objectives and their practical realization in the ® eld. 9. Conclusions

The options for wider dissemination need to be assessed, and the pivotal problem is the correct identi® cation of the `potential target users’. As presently constructed the Wetlands GIS can already satisfy many of the apparent needs of research scientists, most of whom are capable of direct use of the GIS, following the design of a graphical user interface. Complex ecological questions can be answered. There is the ability to relate these to management data, also available within the system. This links the ecological questions to the possible constraints of farming policy. However, many of the other potential users might not feel so con® dent, nor might they ® nd that it addressed the questions that preoccupied them. Adaptation of the GIS to the needs of other such users might imply some simpli® cation of the messages arising from its use. The type of questions these users are likely to ask need to be anticipated and answers provided within a more accessible package. The package adopted is likely to be based on `desk-top PC’ technology and customized at di erent levels for the key types of target user. However, simpli® cation must be followed with caution, eschewing the temptation to convert an investigative tool like the W etlands GIS into little more than à nice computer slide show’. Acknowledgements

The study was funded by the Ministry of Agriculture, Fisheries and Food as part of its research into bio-diversity in Environmentally Sensitive Areas. The authors are grateful to all those who provided data for the W etlands GIS , or who allowed access to their land: the Royal Society for the Protection of Birds; ADAS regional sta ; Ecological Surveys ( Bangor); English Nature; Richard Bradford, Geonex UK Ltd and Roy Lambourne. Finally, much of the ecological ® eld data included within the W etlands GIS was recorded by sta from the ITE, and by sandwich students, though particular mention should be made of Wendy Cox, whose e orts on Southlake Moor with ® eld-survey and archive research accounted for the greater part of that section of the GIS. References A rmstrong, A. C., 1993, Modelling the response of in-® eld water-tables to ditch levels imposed for ecological aims, a theoretical analysis. Agriculture, Ecosystems and Environment , 43 , 345± 351. A spinall, R. J., 1994, GIS and spatial analysis for ecological modelling. In Environmental Information Management and Analysis: Ècosystem to Global Scale’ edited by K. M. Williams, J. W. Brunt and S. G. Sta ord (London: Taylor & Francis). A very, M., G ibbons, D. W., P orter , R., T ew , T., T ucker, G., and W illiams, G., 1995,

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