proposal for an inventory of geomorphological heritage in ... · 3.1 landform inventory (mapping)...

Proposal for an inventory of geomorphological heritage in Castilla-La Mancha Region, Spain

J. Caballero1, J. F. Martín-Duque2, R. Carrasco1, F. Fernández-González1, M. A. Sanz2 & J. Bodoque2 1University of Castilla-La Mancha, Spain 2Complutense University, Spain

Abstract

Geological and geomorphological heritage protection has been frequently considered a last-rate priority by organisations and governments, either within their general policy for heritage conservation or particularly within the conservation of nature. In spite of this complaint, a change of this tendency is taking place during the last few years. The growing interest for geological heritage can be seen from the definition of Geosites as a specific form of World Heritage by UNESCO. In addition, a much broader attention to this subject has been paid by the scientific community, environmental educators or the ecotourism sector. The legislation of Castilla–La Mancha Region, Spain, considers the geo(morpho)logical environment to be an important component of Nature. This is the first region in Spain that makes explicit a mandate for the protection of specific landforms. This paper describes the procedures and outcomes of a research project that constitutes the first implementation of this law, concerning the inventory of landforms from their ‘natural heritage’ point of view. Keywords: geomorphological heritage, geosites, nature conservation, landform, landscape, Castilla-La Mancha.

1 Introduction

Geological and geomorphological heritage can contribute to social development in different ways. Among them, the interpretation of the history of the Earth and the evolution of the landscapes are perhaps the most obvious.

Geo-Environment, J. F. Martin-Duque, C. A. Brebbia, A. E. Godfrey & J. R. Diaz de Teran (Editors)© 2004 WIT Press, www.witpress.com, ISBN 1-85312-723-X

Geological heritage is a part of natural heritage. In turn, geomorphological heritage is a constituent component of geological heritage. But the landform and geomorphological concepts go beyond the ‘geologic’ framework. For instance, landforms are close to ‘terrain’, term that refers the surface of the earth regarding many practical connotations and historical land uses. In addition, the visual component of landforms is also obvious, and it links geomorphology with the scenic and artistic components of the land. On the one hand, these particularities broaden and complicate the study of geomorphological heritage [1, 2, 3, 4]. On the other hand, this should lead to consider geomorphological heritage as an invaluable asset, as long as certain landforms can merge more than one value: scientific, educational, tourist, historical, archaeological, spiritual, aesthetic…

2 Geomorphological heritage: consideration and conservation

2.1 Precedents

The consideration of ‘geomorphological heritage’, as we are referring it, is certainly very recent, and it has only received specific treatment once geological heritage has been object of a wider recognition, and once it has been broken down into its different components: tectonical, stratigraphical, palaeontological, mineralogical, geomorphological… The same happens with geological heritage, which derives from the compartmentalization of the more general ‘nature conservation’. Therefore, precedents of geomorphological heritage consideration and conservation are included within the history of the conservation of Nature. The promotion of the modern perception of the inherent or intrinsic worth of Nature has been attributed to the Romantic movement of the late eighteenth and nineteenth centuries in Europe and North America. But the ‘conservation movement’, as an organised activity supported by government, began in the United States [5]. And it was there where the world’s first national park was designated – Yellowstone, in 1872. After the United States precedent, many countries all over the world, mainly in Europe, emulated the conservation philosophy. For the purposes of this paper, it needs to be highlighted that the main reason for establishing many of these first national and natural parks –undoubtedly for Yellowstone— was to protect their geological, geomorphological and landscape ‘wonders’. But, very soon, it happened that biological conservation became the main focus in the nature conservation efforts, and this mainstream is clearly dominant today. All that, even when it has been argued that many national and natural parks are more “landform spectacles rather than merely biosphere reserves” [6, p. 246], and enormous numbers of ordinary people choose every year to visit “visually stunning landform sites”, as Goudie as clearly pointed out [6, p. 246]. This is obvious, for example, for many national parks of the North American West, such as those of the Southern Utah and Northern Arizona area, (Grand Canyon, Arches, Bryce Canyon, Canyonlands, Capitol Reef, Zion…).


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2.2 The current international framework

Within the present international framework, geomorphological heritage conservation takes place through the initiatives of organisms such as the International Union for the Conservation of Nature and Natural Resources (IUCN), the United Nations Educational, Scientific and Cultural Organisation (UNESCO) or its Environmental Programme (UNEP). One of the most outstanding initiatives of worldwide conservation is the World Heritage Sites (WHS) network by UNESCO, concerned with protecting the world’s cultural and natural heritage. Within the 754 WHS existing currently, in 2004 [7], only 43 sites that have been included in the list recognize geological aspects, but it is interesting to notice that at least 33 of those 43, specifically refer to their geomorphological nature (updating for 2004, based on the data by Dingwall (in Gray [5, p. 186-187])). This example reflects, on the one hand that geologic nature is a minority aspect of global conservation, but on the other hand, that geomorphologic heritage has a broad recognition within it. Additionally, it can be seen how geomorphological assets have their own singularity, as far as many landforms and landscapes are connected with archaeological, historical, spiritual and aesthetic values [7]. As far as projects for geological conservation are concerned, two initiatives stand out. The Global Geosites, established by the IUGS with the support of UNESCO [8], and Geoparks, also supported by UNESCO. In both cases, geomorphological features are included maintaining their own entity. Again, it is argued here that the geomorphic aspects of the land can help to establish links between Society and Nature. Finally, there is a specific initiative that promotes the study of geomorphological heritage. This is the Geomorphological Sites Working Group of the International Association of Geomorphology [9], which is producing specific publications on ‘geomorphosites’ [10].

2.3 The Spanish situation

Similar to the international context, the beginning of geological and geomorphological conservation in Spain was integrated within the more broad ‘nature conservation’ concept. Spain has the honour of having one of the first National Parks Laws in the world (1916), inspired in the United States model. This law made possible the early declaration of the two first Spanish National Parks – the Covadonga Mountain (1916) and the Ordesa Valley (1918). These declarations were also the beginning of an important conservationist movement in Spain, which reaches up to the 1930s. The contribution of both the biotic and abiotic aspects of nature was more balanced then than now, and a very active role was played by geologists and geomorphologists during these years, with the outstanding figure of Eduardo-Hernandez Pacheco. Unfortunately, after this promising beginning little was done for many decades, and it was not until the appearance of the Law of Conservation of Natural Spaces and Wild Flora and Fauna, in 1989, that conservation received a new boost. This law established four categories of protected natural areas –


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National Parks, Natural Reserves, Natural Monuments and Protected Landscapes, being the Natural Monuments category the one which have resulted more suitable for protecting abiotic nature. After the 1989 national law, the 17 Autonomous Communities of Spain have developed their own legislation for nature conservation [see 11]. The Nature Conservation Law of the Castilla-La Mancha Region is included in this framework [12]. For the purposes of our discussion, it is noticeable that geological and geomorphological assets are given specific representation in this law, and this is actually the starting point of the project which is explained in this paper. The referred research project is called Study of the Vegetation, Flora and Geomorphological Sites of the Montes de Toledo Area. A part of this project is to develop a methodology for the inventory and assessment of the geomorphological heritage. This paper explains the procedures followed and the obtained results so far.

3 Elaboration of a geomorphological heritage GIS for the Montes de Toledo area, Castilla-La Mancha, Spain

Although the Nature Conservation Law of Castilla-La Mancha has a regional scope, indeed it seeks to serve as an instrument for a detailed inventory of both the habitat and geomorphological elements of special interest of the region. Actually this law is promoting habitat and geomorphological inventories with a potential use for local planning. The aim of these inventories should be to provide municipal planners with information about what elements of the land are more valuable (and why) and therefore should be preserved of any development. The habitat inventory for the region has been extensively developed, derived from a mandate of the European Habitats Directive of 1992 and its Nature network. However, the geomorphological inventory is in its first stages. The framework for this inventory is specified by the Appendix 1-D of the already referred Nature Conservation Law of Castilla-La Mancha [12, p. 4090] (table 1).

Table 1: Geological and geomorphological elements of special interest for the Spanish Castilla-La Mancha Region [12].

Nature Conservation Law, Castilla-La Mancha, Appendix 1–D Fluvial canyons and watergaps. Natural waterfalls. Seasonal or permanent wetlands. Outstanding quartzite ridges. Craggy landforms and sheeting on plutonic rocks. Natural scarps. Active scree and talus slopes. Variated karren solutional sculptures and tower karst. Dolines. Tufa barriers and tufa constructions related with karstic springs. Natural caves, including their speleothems. Volcanic landforms. Palaeontological sites. Aeolian landforms. Snow-glacier landforms. Noticeable Pleistocene periglacial landforms. Stromatolitic structures within fluvial channels and lacustrine environments. Palaeosoils of scientific interest.


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3.1 Landform inventory (mapping)

An area of 1400 km2 of the south-western portion of the Toledo province, within the ‘Montes de Toledo’ and ‘La Jara’ natural regions, was selected for carrying out the first geomorphological inventory of the project (figure 1). Traditional geomorphological mapping show landforms classified by their morphogenetic origin [13, 14]. In many cases, the applicability of these maps is not direct, and they need to be simplified, interpreted or transformed in derivative ones. The maps elaborated for this project maintain that genetic classification, but they have been conceptually simplified and stored in digital format. This procedure allows a more friendly management, concerning the use of the information. It allows, for example, an easy updating of data or the construction of relational data bases, so that information can be easily analysed or retrieved depending on the objective.

Figure 1: The rectangles (each coincident with a 1:25.000 sheet of the Spanish National Topographic Map) show the area selected for the inventory of geomorphological heritage, within the Montes de Toledo and La Jara natural regions, Toledo Province, Castilla-La Mancha Region, Spain.

The geomorphological mapping was carried out by acquiring and sorting landform information coming from different sources.


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3.1.1 Bibliographic and cartographic compilation Those maps and publications referred to the studied region were collected, and the information concerned to the objectives of the inventory (Appendix 1-D) was selected. 3.1.2 Elaboration and analysis of a Digital Elevation Model (DEM) Most of the geomorphological elements of special interest to be mapped are associated with high slopes and escarpments (fluvial canyons and watergaps, quartzite ridges, craggy landforms on plutonic rocks, natural scarps, active scree and talus slopes…). For that reason, and with the aim of obtaining an objective topographic classification of the land, a Digital Elevation Model (DEM) was elaborated. The altitudinal data was obtained from the Geographic Institute of Spain (IGN), consisting in a 25-metre net of height data (BCN-25) (figure 2).

Figure 2: Orthophoto superimposed to the 25-m DEM of the Geographic

Institute of Spain (IGN). Tagus river gorge, Valdeverdeja (Toledo). North to the upper left corner of the scene.

From the DEM, a slope map was produced, including the following slope classes: 0-15º, 15-25º, 25-35º, 25-55º and 55-90º (figure 3). This map served as a good starting point for delineating some geomorphological elements, after a relationship between specific landforms and slope classes was established. 3.1.3 Aerial photo-interpretation The traditional stereoscopic interpretation of 1:30.000-scale vertical aerial photographs was used as the main source of information for the delineation of


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the singular landforms. Elements smaller than 500 m2 were not mapped, due the scale of the project.

Figure 3: Example of slope classification. Tagus river gorge, Valdeverdeja

(Toledo).

3.1.4 Field work Field work surveys served for sorting and checking the amount of information compiled, as well as for characterizing and describing the selected landforms. 3.1.5 Use of aerial orthophoto The information collected from bibliographic sources, digital elevation models, aerial photo-interpretation and field work was finally represented on a paper-copy of a high resolution aerial orthophoto, printed at a 1:15.000 scale (aerial orthophoto provided by the Agriculture Ministry of Spain). The orthophoto was used to represent the selected landforms because it blended the realistic representation of the land (see again figure 2) with the cartographic precision of a detailed topographic map. 3.1.6 Digitizing The inventoried geomorphological elements of special interest, identified and sorted from different sources, and delineated on the aerial orthophoto, were finally digitized in a vector format. Each landform element was codified, and the code was used to link with the data base.


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3.2 Characterization and assessment

A first assessment of the selected landforms, according to their singularity, has been made, following the scale: ubiquitous (0), common but with local interest (1), rare, and characteristic of a specific process or landscape (2), unique, with national/international interest (3). The continuation of the characterization and assessment will consider, mainly, the potential of a landform for educational and scientific purposes. For that, some of the criteria proposed by Cendrero [15] will be used. These criteria refer mainly to the intrinsic value of a landform, with additional indicators such as: existing number of publications about the site (as a measure of the availability of research/knowledge about it), diversity of elements of interest within the landform, or association with other elements of the environment (archaeological, historic, ethnographic, flora, fauna, and scenery). Other criteria related with their vulnerability or potential of use are considered, such as: degree of preservation, existing threats, accessibility, proximity to towns or cities, number of inhabitants in the surrounding area (see Cendrero [15]).

4 Results

4.1 Classification

Six of the original geomorphological elements of special interest included in the Appendix 1-D of the Castilla-La Mancha Law were recognized in this area: natural scarps, craggy landforms on plutonic rocks, quartzite ridges, wetlands, active talus slope and fluvial canyons. The latter was subdivided in two categories (gorges and ravines), and one class more was added to the inventory (inselbergs). Therefore, all the geomorphological elements of special interest found in this area were classified in nine categories. These categories were also subdivided (for example, natural scarps were compartmentalized in classes such as terrace scarps or fault scarps), computing a total number of 34 subtypes.

4.2 Mapping

A total of thirteen 1:50.000 sheets, corresponding to those of the National Topographic Map of Spain, have been surveyed and mapped, covering an area of more than 280 square kilometres. The appearance of one of these maps is shown at figure 4.

4.3 Characterization and assessment

So far, the project has consisted mainly in the delineation of the geomorphological elements of special interest quoted by the law, and this is the reason for what the main part of the results are cartographic. However, the characterization and assessment of the delineated elements has started, and relational data bases are being built with this information.


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Figure 4: Example of cartographic results (H-682 sheet). Singular landforms

digitized and overlayed to the aerial orthophoto.

One of the tangible results of the project, so far, has been the first delineation of geomorphological areas of regional interest. For that, those landscapes in which an association of geomorphological elements of special interest occur (by density or diversity) were selected (a total number of 14 areas). These areas are representative of fluvial, wetland, granitic and structural morphology.

5 Discussion

Despite they create much of the visual interest of the land, and act as a support of many of their ecological and social functions, landforms have been undoubtedly undervalued as elements of the nature. This means that consideration and conservation of geologic and geomorphologic heritage is still far from the public recognition that has biological conservation now. In this respect, the Nature Conservation Law of the Castilla-La Mancha Region, Spain, offers an adequate framework for the conservation of geomorphological heritage. This law is pioneer in Spain in this respect, as it includes a specific Appendix (1-D) that makes explicit which landforms, as well as other geotic elements, should be preserved. This is certainly an unquestionable achievement, despite that there are difficulties for the interpretation of some of the law mandates (for example, what is a Noticeable Pleistocene Periglacial Landform?). In this paper, we have described the protocols used for the inventory and characterization of the geomorphological heritage of the Montes de Toledo region. All that, following the mandate of the referred Castilla-La Mancha law.


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None of the procedures followed are new, but new can be considered the purpose for what landforms have been mapped. From a methodological point of view, the use of the aerial orthophoto has been quite satisfactory, because it blends the realistic representation of the land with the cartographic precision of a map. Additionally, the use of GIS tools for geomorphological data storage, processing, output, use and management is resulting to be very effective.

References

[1] Morisawa, M., Evaluating Riverscapes (Chapter 6). Environmental Geomorphology, ed. D.R. Coates, Publications in Geomorphology, State University of New York: Bringhamton and New York, pp. 91-106. 1971.

[2] Linton, D.L., The assessment of scenery as a natural resource. Scottish Geographical Magazine, 84, pp. 218-238, 1968.

[3] Leopold, L.B., Quantitative comparison of some aesthetic factors among rivers. Geological Survey Circular 620, Washington, pp. 1-16, 1969.

[4] Brush, R.O., Landform and scenic preference: a research note. Landscape Planning, 8, pp. 301-306, 1981.

[5] Gray, M., Geodiversity. Valuing and conserving abiotic nature, Wiley: Chichester, 434 pp, 2004.

[6] Goudie, A.S., Aesthetics and relevance in geomorphological outreach. Geomorphology, 47 (2-4), pp. 245-249, 2002.

[7] UNESCO, http://whc.unesco.org/nwhc/pages/home/pages/homepage.htm [8] Cleal, C.J., Thomas, B.A., Bevins, R.E. & Winbledon, W.A.P. Geosites, an

international geoconservation initiative. Geology Today, 15, pp. 64-68. 1999. [9] IAG, http://www.geomorph.org/wg/wggs.html [10] Coratza, P. & Marchetti, M. (eds). Geomorphological Sites: research,

assessment and improvement. IAG Workshop Proceedings. Modena (Italy), 19-22 June 2002. Dipartimento di Scienze della Terra, Universitá degli Studi di Modena e Reggio Emilia: Modena, 118 pp., 2002.

[11] Fernández Delgado, J.M., Apuntes sobre geomorfología y patrimonio natural. Estudios Recientes en Geomorfología – Dinámica Territorial. Sociedad Española de Geomorfología & Departamento de Geografía (Universidad de Valladolid): Valladolid, pp. 576-603, 2002.

[12] Ley 9/1999, de 26 de mayo, de Conservación de la Naturaleza de Castilla-La Mancha, D.O.C.M. nº 40, 12 de junio de 1999, pp. 4066-4091.

[13] Klimaszewski, M., Detailed geomorphological maps, ITC Journal (1982-3), pp. 265-271, 1982.

[14] Demek, J., (ed.), Manual for Detailed Geomorphological Mapping, Academia: Prague, 320 pp., 1972.

[15] Cendrero, A., Propuestas sobre los criterios para la clasificación y catalogación del patrimonio geológico. El Patrimonio Geológico, Ministerio de Obras Públicas, Transporte y Medio Ambiente: Madrid, pp. 29-38, 1996.


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