COBISS: 1.01 EVALUATING THE HUMAN DISTURBANCE TO KARST ENVIRONMENTS IN SOUTHERN ITALY OCENJEVANJE SPREMEMB KRAŠKEGA OKOLJA ZARADI VPLIVA čLOVEKA V JUžNI ITALIJI Fabiana CALo1 & Mario PARISE2 Abstract UDC 502.6:551.44(450.75) Fabiana Calo & Mario Parise: Evaluating the Human Distur-bance to Karst Environments in Southern Italy Karst environments are extremely vulnerable to degradation and pollution. Although the carrying capacity of these natural environments is low, a variety of human activities is implement-ed on karst settings generating impacts at the surface and sub-surface. To evaluate the degree of disturbance to typical karst environments in the Mediterranean basin, two areas have been selected in Apulia (south-eastern Italy). Te human-induced ef-fects are being assessed by applying a recently developed Karst Disturbance Index (KDI), based on a categorical framework encompassing physical, biological, and social aspects, and the evaluation of a number of indicators for each category Scores are assigned to the indicators, to assess the severity and the ex-tent of the human impacts on the karst environment. Knowl-edge of the study areas derives from a combined use of direct experience and feld surveys, and the critical evaluation of data available from research articles and local organization reports. Since this approach is an holistic and comprehensive method, diferent scientifc branches and law issues have been consid-ered. Te results so far obtained for the study areas highlight the urgent need of a sustainable management of anthropogenic activities: for example, quarrying and stone clearing, both ex-tensively widespread, are among the most dangerous practices for karst surface and subsurface landforms in Apulia. Tese activities are heavily changing the original karst landscape and causing the partial or total destruction of natural caves. Tis study represents a preliminary evaluation of the human disturbance to karst in Apulia, but has to be necessarily integrated by further applications in other areas of the region, aimed at a better understanding of the potentiality of the approach and its feasibility in diferent karst settings. keywords: karst disturbance, human impact, Karst Disturbance Index, Apulia, Italy Izvleček UDK 502.6:551.44(450.75) Fabiana Calo & Mario Parise: Ocenjevanje sprememb kraškega okolja zaradi vpliva človeka v južni Italiji Kraško okolje je izredno občutljivo za uničevanje in onesnaževanje. čeprav je »nosilna sposobnost« tega naravnega okolja majhna, so na krasu najrazličnejše človeške dejavnosti, ki vplivajo na njegovo površje in podzemlje. Da bi ocenili stopnjo takih sprememb na značilnem kraškem ozemlju v Sredozemlju, je bilo izbranih dvoje področij v Apuliji (jugovzhodna Italija). Posledice, ki jih je povzročil človek, so bile ugotovljene s pomočjo pred kratkim razvitega »indeksa sprememb na krasu«, ki upošteva fzične, biološke in družbene vidike, obenem pa so bili za vsako skupino ovrednoteni številni pokazatelji. Ti so bili točkovani in tako sta bili ovrednoteni intenzivnost in obseg človekovega vpliva na kraško okolje. Poznavanje obravnavanega ozemlja temelji tako na neposrednem opazovanju kot na terenskih preučevanjih ter na kritičnem ovrednotenju podatkov iz strokovnih člankov in poročil lokalnih združenj. Ker gre za celostno in vsestransko metodo, so upoštevane različne znanstvene panoge in zakonodaja. Tako dobljeni izsledki za preučevana ozemlja kažejo na nujnost sonaravnega urejanja človeških dejavnosti, kot sta npr. lomljenje in čiščenje kamenja, oboje je na široko razširjeno in ki predstavljata najbolj nevarno dejavnost za kraške površinske in podzemeljske oblike v Apuliji. Ti dejavnosti močno spreminjata prvotno kraško površje in povzročata delno ali celotno uničenje podzemeljskih jam. Ta študija predstavlja predhodno oceno sprememb na krasu v Apuliji in bi morala biti vključena v bodoče raziskave drugih ozemelj te regije, da bi lahko bolje razumeli prednosti te metode in njeno uporabnost za različna kraška okolja. ključne besede: spremembe na krasu, vpliv človeka, indeks sprememb na krasu, Apulija, Italija. 1 External collaborator CNR-IRPI, Bari Italy; e-mail: fabianacl@libero.it 2 CNR – IRPI, Sezione di Bari, Via Amendola 122, I - 70125 Bari, Italia; e-mail: m.parise@ba.irpi.cnr.it Received / Prejeto: 14.07.2006 ACTA CARSOLOGICA 35/2, 47–56, LJUBLJANA 2006 FABIANA CALo & MARIO PARISE INTRODUCTION: THE DISTURBANCE INDEX FOR KARST ENVIRONMENT Karst, with its surface and subsurface landforms such as closed depressions, sinkholes and caves, is among the most fragile natural environments of the world, and ex-tremely susceptible to any change. Karst systems are non renewable resources but, nevertheless, they are increas-ingly being disturbed by a variety of human activities generating impacts both above and below ground (wil-liams, 1993). Many anthropogenic actions cause great trans-formations and degradation of karst regions, including quarrying and mineral extraction, deforestation, agri-cultural practices, illegal waste dumps in natural cavi-ties, tourism in caves. All these activities may result in negative efects on karst, such as pollution and depletion of water resources, changes of the natural morphology and hydrology, decline of animal species, etc. (Parise & Pascali, 2003). Complexity of karst, where several diferent catego-ries interact in creating the overall ecosystem, requires to consider and analyse any component of karst, both individually and in the reciprocal relationships with the others, in order to safeguard and manage it in a sustain-able way At this aim, only an holistic, comprehensive approach, addressing physical, economic and social fac-tors, can efectively assess the threats to karst areas (Van Beynen & Townsend, 2005). In order to reduce the karst system to elements easily studied for the evaluator, this article applies the method recently proposed by Van Beynen and Townsend (2005) to measure factors of karst disturbance (Fig. 1) based on a framework divided into fve broad categories, each en-compassing more detailed attributes: Geomorphology that encompasses surface landforms, soil and subsurface karst; Atmosphere that deals with air quality; hydrology that 48 fig. 2: Geological sketch of Apulia. Explanation: 1) recent clastic cover (Pliocene – Pleistocene); 2) bioclastic carbonate rocks (Paleogene) and calcarenites (miocene); 3) platform carbonate rocks (Cretaceous). Te two insets refer to the study areas. ACTA CARSOLOGICA 35/2 – 2006 EVALUATING THE HUMAN DISTURBANCE TO KARST ENVIRONMENTS IN SOUTHERN ITALY Published/ unpublished research articles INFORMATION ABOUT THE ENVIRONMENT SCORE ASSIGNMENT rating 0 rating 1 rating 2 rating 3 Karst Disturbance Index Identifcation of LD indicators LD rating INDICATIONS FOR THE KARST MANAGEMENT Critical evaluation of the degree of disturbance Socio-economical implications for land use planning Research felds with insufcient data fig. 1: flow chart illustrating the methodology followed in this study. ACTA CARSOLOGICA 35/2 – 2006 49 FABIANA CALo & MARIO PARISE includes surface practices infuencing water quality and quantity, and water quality of springs; Biota that concerns the vegetation disturbance and the subsurface biota in cave and in groundwater; and Cultural factors that include human historical artefacts, stewardship of karst region and building infrastructure. Te degree of disturbance of a certain attribute is indicated through a pre-established set of associated in-dicators, from those most destructive for surface karst as quarrying/mining (Gunn, 1993), and dumping waste in sinkholes and cavities, to the less apparent but equally dangerous use of pesticides and herbicides in agriculture, and so on. Each indicator, that can be appraised by the evaluator from historical data, feld observations, pub-lished and unpublished research articles and local gov-ernment reports, is assigned a score from 0 to 3 based on severity and extent of the variable being considered: rating 0 means no karst disturbance, rating 1 indicates localized and not severe impact, rating 2 widespread and severe impact, whilst when a catastrophic impact is ob-served rating 3 is assigned. To determine the degree of disturbance of a par-ticular region, the evaluator should know what an un-disturbed karst system is, and assume it as the ideal reference system. Tis might be relatively simple for some indicators (water quality, extent of quarrying, etc), but very difcult for others (loss of biodiversity, human-in-duced condensation/corrosion, etc). Finding locations without human infuence may be extremely difcult, which forces the evaluator to use as baseline those areas with minimal human perturbation. If an indicator cannot be applied to the study area, it has to be deleted from the evaluation, while if it is rel-evant in the area but no information is available, a “Lack of Data” (LD) has to be indicated. At the end of the evaluation, the number of LDs divided by the total number of used indicators gives a measure of the confdence of the index: LD rating < 0.1 would inspire high confdence in the determined index, while LD rating > 0.4 suggests that more study is required before application of the index can be carried out in that location. Once all feasible indicators have been scored, the evaluator calculates the Karst Disturbance Index. Scores are summed and the total is divided by the highest pos-sible score to attain a value between 0 and 1, where the latter indicates an highly disturbed system and the lowest value a pristine system. Classes of Karst Disturbance In-dex, according to Van Beynen and Townsend (2005), are reported in Table 1. Score Degree of disturbance 0.8 – 1 Highly disturbed 0.6 – 0.79 Moderately disturbed 0.4 – 0.59 Disturbed 0.2 – 0.39 Little disturbance 0 – 0.19 Pristine tab. 1: Classifcation of disturbance (afer van Beynen & townsend, 2005). CASE STUDIES IN APULIA Apulia region is the emerged south-eastern part of the Adriatic Carbonate Plate which is formed by Jurassic-Cretaceous limestones and dolostones covered by Terti-ary and quaternary clastic carbonates, mostly calcaren-ites, and subordinate clays and sands. From the Lower Pleistocene, the region was interested by a general uplif-ing, until it reached the present confguration (Doglioni et al., 1994). Apulia is fragmented by high dip, Nw-SE striking, faults into uplifed and lowered blocks (Ric-chetti et al., 1988). Due to the widespread presence of carbonates, surface and subsurface landforms were ex-tremely involved in karst processes that produced an ex-tensive network of underground cavities and conduits. Te landscape is generally f at, characterized essentially by landforms of karst origin, whose best morphologi-cal expressions are identifable on the Murge Plateau of inland Apulia (Neboit, 1974; Sauro, 1991). Over large 50 ACTA CARSOLOGICA 35/2 - 2006 portions of the region, the natural landscape has been strongly modifed by man, also thanks to the smoothed morphologies that facilitated land use changes. Te Murge Plateau is a planation surface cut in the Cretaceous limestones during Paleogene and Neogene. From the highest elevations (678 m a.s.l. near Mt. Cac-cia), the plateau slowly degrades toward the Adriatic Sea to the east, through steps of marine terraces. Two main districts can be identifed: High Murge, which cor-responds to the inner portion of the plateau, and Low Murge, closer to the Adriatic coastline. In this study, we apply the Karst Disturbance Index method to two areas, located respectively in the two aforementioned districts. MINERVINO MURGE AREA (HIGH MURGE) Selection of the area in the surroundings of the town of Minervino Murge for the present study was dictated, be- EVALUATING THE HUMAN DISTURBANCE TO KARST ENVIRONMENTS IN SOUTHERN ITALY sides its very interesting karst features, by the fact that it is comprised within the boundaries of a recently estab-lished natural park (Alta murgia Natural Park), which to-tal surface is around 70,000 ha. Te park was established with a National Law in 1998, afer many years of debate about the boundaries of the park, and many discussions about the permitted activities within its limits. Tis part of the Murge Plateau was originally devoted to pasture, and characterized by bare karst landscape with limestone rocks protruding from the ground surface. Te few areas where residual soils and terra rossa concentrated were slightly incised valleys, locally called lame, that consti-tuted a sort of oasis where the farmers were able to per-form agricultural practices. In the last decades, two main anthropogenic activities spread out in this area, which resulted in heavy changes in the natural landscapes: quarrying, and stone clearing (Fig. 3). quarrying is very fig. 3: quarrying and stone clearing are the main anthropogenic activities degrading the original karst landscape at minervino murge. Te photo shows an overall view of the southern slope of mount Scorzone. widespread due to the common use in Apulia of carbon-ate rocks as building and ornamental materials. Advance of quarrying is carried out without any concern for the natural caves, many of which have been damaged or de-stroyed by quarrying (Fig. 4). In addition, once the quar-rying activity ceases, it is very common the use of the abandoned site for illegal dumping of solid and liquid wastes. Te considerations above led to assign high val-ues to the indicators quarrying/mining (rating 3) and in-dustrial and petroleum spills or dumping (rating 2). As regards the latter indicator, we considered as brownfelds (heavily polluted sites) any abandoned quarry where the presence of wastes was detected. Repeated surveys performed in the last years, in-tegrated with interpretation of multi-year aerial photos allowed to quantitatively evaluate the advance of quar-rying activities (Fig. 5), and the areas involved in land fig. 4: intense quarrying activities resulted at several sites in the minervino murge area in destruction of caves, as shown in this photo. use change. Tis was then integrated by feld surveys and speleological explorations, that further highlighted the destruction of a high number of caves in the area. Te data so collected clearly show that the area around Minervino Murge is one of the most degraded in Apulia as regards disturbance of the karst environment, with loss of the original landscape and destruction of the natural caves. fig. 5: Areal increase of quarrying at minervino murge in the time span 1976-2005. Numbers on the x axis refer to the six 1:5,000 scale topographic maps that were used for air photo interpretation. Te quarrying activity coupled in the last 30 years with intensive stone clearing practices, even favoured by public subsidy from the European Community Tese subsidies, addressed to changes in the land use for intro-ducing new crops, resulted in the High Murge in trans-forming the original bare karst in a landscape which is unnatural for this area, with wide development of corn-felds. Most of the rocks resulting from clearing of the felds, and quarrying activity as well, are ofen dumped into swallow holes and caves (Fig. 6), or piled around karst depressions. Besides the negative efect on the karst landscape, these actions are extremely dangerous for cav- ACTA CARSOLOGICA 35/2 – 2006 51 FABIANA CALo & MARIO PARISE ers, due to instability of the dumped and/or piled rocks. Tus, the indicators inflling and dumping were consid-ered, respectively, with rating 2 and 3. fig. 6: Stone clearing practices produced the formation of non natural cornfelds in the minervino murge area, and in piling of rock debris in the proximity of cave entrances (two persons for scale on the rock pile). Other rocks have been dumped as well into the cave, creating a serious danger for cavers, due to instability of the rocks, both outside and within the cave. At present, thousands of hectares of the original pas-tures have been transformed, and this has ofen resulted in later abandonment of the felds, due to intense erosion. In fact, stone clearing is carried out through the use of modern technologies and machinery, able to crush the carbonate rocks destroying the epikarst, and eliminating the soil. when it rains, even on gentle slopes surface run-of develops and intense erosion starts. Erosional pro-cesses may be so severe to determine onset of both linear and areal erosion on the slopes, through development of rills and gullies. Te indicator erosion has been therefore assigned a rating 2. Another consequence of the stone clearing practice is fooding in subsurface karst, as a fur-ther efect of the land use changes at the surface: similarly than the previous indicator, also fooding was considered to have a severe impact, scored as 2. Caves in the Minervino Murge area are character-ized by vertical entrances, with some meters-deep shafs. Difculty in accessing the caves, which is limited only to expert cavers, resulted in high protection and safeguard of the caves and the deposits therein from removal and vandalism, and strongly limited other problems related to frequent visits by man. Tis had important conse-quences in the attribution of scores to some indicators. In practice, fve indicators belonging to diferent categories were listed as 0. Te category Biota was the most difcult to evaluate at the Minervino Murge area. Torough bibliographical research produced very little results in terms of published articles. Furthermore, nothing was found to allow a com-parison at diferent times of the species richness and den-sity of population, which is required to assign scores to the biota indicators. Tus, four out of the fve indicators of this category were considered as Lack of Data. vegetation disturbance was the only one that ap-plied to the case study in the Biota category: a score 3 was assigned to this indicator, due to the long history of deforestation in the area, that brought to have today only very few remnants of wood cover (most of these is repre-sented by re-forested areas). Another signifcant problem is the state of the present vegetation, since lack of mainte-nance of woods has resulted in a situation highly prone to wildfres, and with several non wealthy trees and plants. To cover even this issue of the vegetation, a new indicator (State of vegetation) was introduced, and again a score 3 was assigned. Many of the problems related to anthropogenic ac-tivities in the Minervino Murge area remained unsolved even afer establishment of the Alta Murgia Natural Park. Tis was mostly due to the lack of control by the Local Authorities, combined with a public indiference toward safeguard of the natural environment from large sectors of the population in the area. For these reasons, when evaluating the indicators belonging to the category Cul-tural factors, some negative scores have been assigned (2 for Regulatory protection, 3 for enforcement of regula-tions, again 2 for both Public education and building of roads). Te Karst Disturbance Index in the Minervino Murge area was determined using 26 indicators (Table 2), and resulted in a value of 0.49, which means “Disturbed” (Table 1). Four indicators were considered as LDs, that resulted in LD rating 0.15, corresponding to good con-fdence. Te difculty in accessing the natural karst caves in the area, due to vertical entrance of most of the caves, has been before mentioned. Tis difculty afects the scores of fve indicators (shown in italics in Table 2). Interest-ingly, if we do not take into account these fve 0 scores, the karst disturbance index for the Minervino Murge area rises to a value of 0.6 (see values in brackets in Table 2), falling in the upper range of the “Moderately disturbed” class. Accordingly, the LD rating changes from 0.15 to 0.19 because of the lower number of indicators used, but still indicates good confdence of the data. CASTELLANA-GROTTE AREA (LOw MURGE) Castellana-Grotte is worldwide famous due to the re-markable, more than 3 km long and more than 120 m deep, caves, which were explored for the frst time in 1938, and soon afer that became one of the most visited tourist caves in Europe. Discovery of the caves played an 52 ACTA CARSOLOGICA 35/2 – 2006 EVALUATING THE HUMAN DISTURBANCE TO KARST ENVIRONMENTS IN SOUTHERN ITALY tab. 2: Karst disturbance index for the two study areas. Te numbers between brackets at minervino murge derive from deleting the fve indicators shown in italics in the table (see text for explanation). for details about each single indicator, the reader is invited to refer to the paper by van Beynen & townsend (2005). category indicator MINERVINO MURGE CASTELLANA GROTTE Geomorphology Quarrying/mining 3 2 Flooding (surface) 0 1 Stormwater drainage 2 2 Inflling 2 2 Dumping 3 2 Erosion 2 1 Compaction 1 2 Flooding (subsurface) 2 1 Decoration removal 1 2 Mineral/sediment removal 1 2 Floor sediment compaction 0 1 Atmosphere Desiccation 0 1 Condensation/corrosion 0 2 Hydrology Pesticides/herbicides 1 2 Industrial and petroleum spills 2 2 Algal blooms deleted deleted Changes in water table 1 1 Changes in cave drip waters 1 1 Biota Vegetation removal 3 2 State of vegetation 3 1 Species richness (cave) LD 1 Population density (cave) LD 1 Species richness (groundwater) LD LD Population density (groundwater) LD LD Cultural factors Destruction/removal of historical artifacts 0 2 Regulatory protection 2 2 Enforcement of regulations 3 2 Public education 2 1 Building of roads 2 2 Building over karst features 1 2 Construction within caves 0 2 TOTAL NUMBER OF USED INDICATORS 26 (21) 26 KDI 0.49 (0.6) 0.57 TOTAL NUMBER OF LDs 4 (4) 2 LD RATING 0.15 (0.19) 0.08 important role in the tourist development of this small adding Grotte, and thus becoming the present Castel-town of Low Murge, that modifed its name in 1950, by lana-Grotte. ACTA CARSOLOGICA 35/2 – 2006 53 FABIANA CALo & MARIO PARISE Te show cave is only one of the many features of this part of Apulia, where both surface and subsurface karst landforms are widespread (Parise, 1999). Te main diferences with the frst territory dealt with in the pres-ent paper are that Castellana-Grotte and the surrounding territory develop at lower elevations (between 330 and 240 m a.s.l.), and the caves are not prevailingly vertical. As for the anthropogenic environment, the show caves, combined with the vicinity to the Adriatic coastline, a further reason of attraction for thousands of tourists dur-ing the summer season, produced in Low Murge a much greater presence of mans activities and infrastructures. Several consequences on the natural karst environment had to be registered, including diversion of the natural runof, and of the water infltration rate in the rock mass as well, with greater possibility of occurrence of surface fooding (Fig. 7). fig. 7: Surface fooding at Castellana-Grotte, as a consequence of a severe rainstorm. without entering into the details of every single in-dicators, it has to be noted that in the Castellana-Grotte area no score 3 was assigned (Table 2), but, at the same time, none indicator had score 0, which means that some negative efects from human activities had to be registered within each indicator of all the categories. For example, the quarrying activity is not so intense as in High Murge; nevertheless, small quarries are present in the area, lo-cally very close to signifcant subsurface karst features. In some cases, anthropogenic activities are still produc-ing negative efects, irrespective of the existing laws and prohibitions (Fig. 8). Due to the easiness in accessing the caves, many of the indicators that in the frst study area had score 0, in this case presented problems, because of vandalism, removal of sediments and materials, and foor sediment compaction. At the same time, access of man into the fig. 8: Pozzo Cucu cave (fig. 8a) is one of the most remarkable caves in the Castellana-Grotte territory. Even though the cave was declared of interest for the European Community, due to its peculiar cave ecosystem, some anthropogenic works (fig. 8b) strongly altered the natural landscape above the cave in the last years. caves also had negative consequences for the biota environment. Besides these problems, the presence of the Castel-lana show caves adds further negative efects, as usual in show caves frequented by high number of tourists (Cigna, 1993; Pulido Bosch et al, 1997; Aley, 2004): changes in the cave environment, development of lampenfora as a consequence of the lighting system, construction within caves for trails and pathways, and so on. Te Karst Disturbance Index in the Castellana-Grotte area was therefore determined using 26 indicators, and resulted in a value of 0.57 (Table 2), corresponding to the upper range of the “Disturbed” class. Two indicators were considered as LDs, that resulted in LD rating < 0.1, corresponding to high confdence 54 ACTA CARSOLOGICA 35/2 – 2006 EVALUATING THE HUMAN DISTURBANCE TO KARST ENVIRONMENTS IN SOUTHERN ITALY DISCUSSION AND CONCLUSIONS Determining the karst disturbance can be very difcult because of the inherent complexity of karst systems, and subjective because it requires interpretation of the karst environment by the expert, depending upon her/ his background. For example, a geologist might con-centrate on geomorphology neglecting the subsurface biota or the water quality Since the method lists all the categories for which data should be collected, and uses pre-established indicators, the need for the evaluator to decide what is important to measure is strongly reduced. Furthermore, the utilized scoring system limited to four possibilities reduces much of the uncertainty associated to multi-level scoring systems, and prevents the evaluator from consistently choosing a middle value, forcing him to be more decisive. It has to be stressed that this approach is based upon some simplifying hypothesis: frst, the index is considered to be applicable for all karst regions, regardless of the dif-ference in karst types; secondly, any change to the karst environment is evaluated as caused by human impact. Karst is, however, characterized by natural variability over space and time (williams, 1993); application of the index to heterogeneous areas, where two or more types of karst are present, should be performed with great care. In addition, it is sometimes difcult to discriminate be-tween human-induced environmental changes and those caused by on-going natural processes. A fnal, but not less important, assumption of the method is the availability of data; actually, this varies from region to region, and depends on the thorough-ness of studies and research undertaken for that specifc area. Trough the Lack of Data, the index includes this aspect and allows to provide a measure of the adequacy of the available information, and to highlight those karst regions where more research activity is needed. Notwithstanding these simplifcations, the Karst Disturbance Index can be adapted to any karst region, and this also contributes to improving the ability to com-pare the degree of disturbance to karst among diferent locations. It can serve as a standard tool for the evaluator (a karst scientist having the experience needed to inter-pret the available data) to provide a quantitative measure of the human impact, and it might help local adminis-trations to contrast the increased human pressure and to address the sustainable management of karst environ-ments. Te present study, through implementation of the Karst Disturbance Index to two areas in the Apulian karst of southern Italy, has shown the usefulness of the approach for a preliminary evaluation of the degree of disturbance in karst, as an help toward a better under-standing of the impacts to the natural environment de-riving from mans activities. At the same time, the need of more detailed research and analysis in disturbed karst areas was well highlighted in both the areas, where a strong contrast occurs between the existing laws for protection and safeguard of the environment, and their real enforce-ment. Tis latter, in particular, has produced and, sadly to say, is still producing as well, heavy degradation, destruc-tion of caves, and frequent loss of the karst landscape in several sectors of the Apulia region ACKNOwLEDGEMENTS we warmly thank Professor Ugo Sauro for his useful suggestions on the frst draf of the paper. 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