Geomorphological Aspects of the Human Impact in the Alpine Area of Southern Carpathians ( Romania )

This paper deals with some human geomorphological aspects concerning the impact in the alpine area of the Southern Carpathians (Transylvanian Alps). After fi eld investigations and taking into account the major effects of road building, military and mining activities, pasture and tourism activities in the geomorphological landscape we have the possibilities to present a distinct image of some relevant detailed situations. In our opinion the building of roads in the alpine area is by far the most dangerous way of intervention in the geomorphological landscape of the alpine area of the Southern Carpathians. The construction of these roads has altered the profi le of the slope and new scarps have appeared. This situation associated with the vibrations induced by the traffi c favours frost weathering, rock falling and rolling, coupled with the emergence of specifi c deposits and landforms (talus cones and scree) and, of course, with vertical and gully erosion, which is very typical of the area of soft rocks and soils.


INTRODUCTION
The Carpathian arch is the vertebral column of the entire relief of Romania.Situated in a millenary oicumenic space, this area was permanently of primordially economic interest due to ore resources, forests and pastures.Throughout the history, under a minor human pressure, the landscape has remained naturally predominant on the inside, evincing a relative harmony between human society and mountain nature.
We want to specify the fact that in the present article we include the entire alpine area lying above the timberline.

THE STUDY AREA
The Southern Carpathians, or the Transylvanian Alps, lie between the Prahova Valley in the East, Timiş-Cerna Passage in the west, the Transylvanian Basin in the north and the Getic and Curvature Subcarpathians in the south (Fig. 1).This mountain range makes up the most massive and highest part of the Romanian Carpathians, having 14 peaks above 2500 m and a maximum elevation of 2544 m in Moldoveanu Peak (Făgăraş Mountains). 10 % of the mountain areas lies above 2000 m.The Pleistocene glaciers reached elevations of 1100-1200 m during their maximum extension, and carved an extensive suite of alpine glacial landforms with sharp peaks and ridges, with cirques, steep slopes and U-shaped valleys (Urdea, 2000).The interaction of paraglacial processes and periglacial phenomena produced a variety of periglacial forms (rockglaciers, talus cones and scree slopes, block fi elds, rock streams, cryoplanation terraces, solifl uction forms; Urdea, 1992).The most part of the Southern Carpathians is composed of crystalline rock and magmatic bodies of granites and granodiorites, especially in the Retezat, Parâng and Ţarcu Mountains.In the Bucegi Mountains the conglomerates and sandstones are characteristic.The climatic conditions specifi c for the high zone of the Southern Carpathians are cold, with the yearly average air temperature of 3° C at Cozia (1577 m), 0.2° C at Bâlea-Lake (2038 m), -0.5° C at Ţarcu (2180 m) and -2.6°C at Omu (2505 m), with an absolute minimum of -38°C.The isotherm of 3°C yearly average temperature indicating the lower limit of periglacial environment according to French (1996), lies around 1700 m a.s.l.From the Peltier diagramme the morphoclimatic systems to which the selected stations are affi liated are periglacial systems (Urdea, Sârbovan, 1995), with physical dominance for Omu and Bâlea-Lake, boreal system for Ţarcu and temperate for Cozia (Fig. 2).The great number of frost days -207,9 days/year at the Bâlea-Lake and 255 days/ year at the Omu Peak -and over 125 of the freeze-thaw cycles, and the great value of the gelivation coeffi cient for the main rocks (e.g.granite -31, granodiorite -36, gneiss -35, amphibolite -44) explains the effi ciency of frost weathering.
The yearly average precipitation is 844.2 mm at Cozia, 1246 mm at Bâlea-Lake, 1180 mm at Ţarcu and 1280 mm at Omu.About 60-75% of the precipitation consists of snow, and the snow cover in the region lasts between 150-210 days a year.The thickness of the snow layer may range between 50 and 370 cm and is highly variable according to the wind action.The heavy rainstorms, occasionally in the late spring, in the summer and in the autumn (217.4 mm at 15.08.1993 at Ţarcu, 195.6 mm at 3.06.1988at Bâlea-Lake) appear to be responsible for the torrential erosion and debris-fl ow activity in the Southern Carpathians.
The timberline runs along generally between 1700 and 1850 m, climbing up mainly on the southern exposed versants and climbing down on the northern exposed ones.

PROBLEM ANALYSIS AND RESEARCH RESULTS
Although the alpine area of the Southern Carpathians belongs to the periglacial and boreal morphoclimatic levels the present-day geomorphological processes are very complex and the periglacial processes are associated with the erosional ones.
Speaking a time frame of the human impact that takes place in the alpine area of the Southern Carpathians we consider that they has been going on ever since Antiquity.An example is represented by the Roman castra of the second Dacian Roman War in the years 106-107 on the Auşelu Mountain at 1980 m a.s.l. and on the Comărnicelu Mountain at 1860 m a.s.l., with typical ditches and earthworks as well as the road connecting them, and we can move on to Dacia's capital, Sarmizegetusa Regia in the Orăştiei Mountains with well visible anthropogenic landforms even today.
It is not unimportant that there are opinions according to which in the Bucegi Mountains in the Babele -Sphynx area and Gugu Mountain (Godeanu Mountains) there might have lived Zamolxys, the supreme God in the mythology of the Dacians.These sacred places for native populations, with typical forms like the Sphynx -with a controversial origin, natural (periglacial eolization and weathering) or an artefact megalith (Fig. 3) -, were a pilgrimage area for a long time, with geomorphologic consequences, connected with the destruction of vegetation layer, which favours the acceleration of erosion processes, and, of course, the appearance of characteristic landforms.
Ever since then and during the whole Middle Ages the alpine area of the Southern Carpathians has been included in the economic circuit thanks to its pastures, proof thereof being the fact that in the medieval documents, near the villages' territories (landowner) one also mentioned the mountains they owned including the sheepfolds and pathways (Urdea, 1983).These pathways are characteristic of the entire mountain area and are known as "plaiuri".We must notify that from the beginning of organised mountain tourism and appearance of the fi rst mountain chalets -due of the initiative of Transylvanian Carpathians Association (,,Siebenbürgische Karpathen Verein'') in 1881, the tourist pathways have been laid out according to these old shepherd pathways.
The construction of the roads in the alpine area is by far the most dangerous way of intervention in the mountain landscape.The most typical case is the one of the Transfăgărăşan Road (Fig. 4).This road was built between 10. 03. 1970 and 20.09.1974 and over 3.8 millions m 3 of material were excavated: 212 000 m 3 of hard rocks, 150 000 m 3 of berms, embankments and ramps in unconsolidated materials and one built an 887 m long tunnel (Urdea, 1999).

Sl. 4. Topografski aspekti Transfagaraške ceste u regiji Balea
Beside the Transfăgărăşan Road we should mention the more poorly laid out roads -and due to these characteristics they are most vulnerable to the activity of the weathering and erosion agents -, accessible only to the carriages, tractors and off road vehicles in the alpine area of the Transylvanian Alps, with the total length of 230 km, present in: Some of these are ancient commercial roads that were connections between Transylvania and Walachia such as "Drumul Neamţului" (German's Road) and Mihai Viteazu's Road in the Vâlcan Mountains.Others were military strategic roads, built before the First World War (Ferdinand's Road) and continued in the Inter-World War period.Also, other roads were built in the communist period like access roads to the sheepfolds with a large number of cattle of the agricultural cooperatives.Therefore one can determine the known geomorphological aspects, connected with erosional features, like those in area of Lespezile, Podeanu, Preotesele and Ţuica Mountain (Făgăraş Mountains).We must mention that in the area of the upper end of pasture roads, the upper timberline descends because the deforestation is a common and "normal'' human effect in the mountain landscape.The construction of these roads has altered the slope profi le and new, anthropogenic scarps have appeared.This new geomorphologic situation, associated with the vibrations induced by the traffi c, favours frost weathering, rock falling (Fig. 5) and rolling -with the emergence of talus cones, talus scree and versants of frost-crumbled blocks -, and of course, the vertical erosion, very typical of the conglomerate area in the Bucegi Mountains (Fig. 6).
These masses of debris are in a disturbed balance, being easily dislodged by avalanches and thus by the debris-fl ow phenomenon.For example, as a result of our fi eld measurements in the 2000-2003 period, we have discovered that between 0.5-3.5 m 3 /year of debris appears per linear metre of the newly created scarp, compared to 0.1-0.7 m 3 /year in the natural slope conditions.
For the debris fl ow phenomenon an abundance of water is required and certain conditions are particularly favourable: a).high rainfall intensity of long duration; b).rainfall on thawing snow pack; c).small drainage basins with steep slopes in which rainfall intensity is uniformly high and runoff is rapid (Van Steijn, 1988;Selby, 1993).The debris fl ows research area are small-scale hill-slope fl ows, debris cones connected to avalanches pathways (Urdea et al., 2004), according to the classifi cation given by literature (Rapp, 1981;Takahashi, 1981).The importance of these phenomena may be measured by the damage they have caused, especially on glacial cirques and valley fl oors and lower cirques and valley sides.In the Transfăgărăşan area the anti-avalanche constructions have changed the direction of the water drainage lines, initiating intensive debris fl ows in the middle and lower part of the slopes.
In the case of the unasphalted roads built in the embankment and/or partial embankment, their ramp is affected by the slope processes.For those cut into the rock, the weathering, falling and rolling associated with the accumulations represent the characteristic processes.For those cut into the slope deposits, mantle-rock and in the soil, the rain, gully and torrential erosion are partially present processes (Niculescu, 1987).The furrows created by the wheels of the vehicles represent the main lines of initiation and then accentuation of the pluvial erosion and gully development.Also the growth of tourist activity together with people tracking down the tourist pathways has caused the herbaceous vegetation to disappear in these areas, which has further initiated and intensifi ed the gullying and erosion processes.An eloquent example is the situation of the Bucegi Plateau where the non-observance of the tourist routes have determined the appearance of many pathways affected by severe erosion processes (Fig. 6).Here, in some areas the density of disorganised pathways reaches 15 km/ km 2 .
Over the last 10 years on the mountain roads and paths in the western part of the Southern Carpathians, especially in the Muntele Mic -Ţarcu Mountains, the degradation has increased due to a new sport in Romania: mountain off road motorcycling and Enduromania contests.
We also mention the traces of the trenches dug out during the warfare WWI operations that took place in the Tulişa Mountains (in the area Curmătura Tulişa -Coasta Laturii -Oboroca), in the Vâlcan Mountains (in the areas Coarnele, Şigleu, Rostovanu, Arcanul), in the Lotru Mountains (in Robul-Murgaşul-Gorganul) area, and in the Făgăraş Mountains (in Budislavul-Suru-Mâzgavul area and Călugărul-Faţa Sf.Ilie-Comarnic area), or in areas where at present military training of troops is taking place, like in Muntele Mic, Parângu Mic, Bucegi Plateau areas etc.
Even pasturage is very old, the use of the alpine lawns, normally does not have major effects on the geomorphological landscape.The intensive and irrational pasture activities associated with bush vegetation burning favour the acceleration of the erosion processes (sheet erosion, rill erosion, gullying and torrential erosion), and, of course, the appearance of characteristic biogenic landforms, like cattle tracks.Land degradation is increased especially in the area of the sheepfolds (Fig. 7), where an impression of the magnitude of this phenomenon one can have considering the density of the sheepfolds placed in the alpine area (Table 1).The highest values are 0,81 sheepfolds/km2 in the Tulişa mountain range, 0,85 sheepfolds/km 2 in the Latoriţa mountain range and 0,95 sheepfolds/km2 in the Căpăţânii mountain range, in contrast with low values in mountain areas situated in protected spaces, like the Retezat National Park, with 0,19 sheepfolds/km2.A true image of land degradation intensity in sheepfolds area is possible if we take into account the fact that many sheepfolds are very old in the same area -from the Middle Age times (Urdea, 1983) -and, in a relatively small area that there are many buildings -some out-houses -, like a small hamlet.
If in the mountain areas with a low and moderate tourist infl ow and with a normal pastoral activity like in the Godeanu, Şureanu, Lotru, Leaota, Cernei, Vâlcan and Căpăţânii Mountains the effects of the human geomorphological impact are insignifi cant, in the Bucegi Mountains (the mountains with the highest tourist pressure) the geomorphological landscape bears the marks of strong human intervention.
The mining activities, are not present except in the Făgăraş Mountains, in Capra Valley, Buda Valley and Podeanu Mountain, with exploitation galleries, spoil banks and access roads made in the communist period of the 80s, years of searching for resources in order to achieve "the economic independence of Romania".Intense human activity often determines an acceleration of the gully and torrential erosion and raindrop erosion impact which leaves its mark on the landscape (ravines, gullies, torrents, small badlands) as it happens in the alpine area of the Bucegi Mountains.The destruction of the vegetal layer making for the installation and then the acceleration of torrential erosion.One can see that the gully erosion and torrential processes set in along the tourist paths (Fig. 6) and along the non-conventional roads.Within the Retezat Mountains, due to the regulations imposed by the existence of The Retezat National Park, fi rst national park of Romania in 1935, the human impact -including the one from the geomorphological point of view -is low, being present only along the tourist paths and around the sheepfolds.
One should not forget the fact that the geomorphological processes, characteristic of the alpine area, intensifi ed and accelerated by the human factor overlap with a signifi cant morphodynamic potential as it has been suggested in the Peltier diagrammes (Fig. 8).We fi nd that the weathering, gelifraction, chemical weathering, mass movement, gullying, fl uvial and rill erosion are moderate and strong.
Otherwise, the processes associated with human intervention in the alpine area are considered as major risk phenomena typical of the Carpathian Mountains (Bălteanu, 1997).

CONCLUSIONS
As a result of the analysis of the human geomorphologic impact on the geomorphological landscape of the alpine area of the Southern Carpathians, we conclude that the impact is strong and with a tendency of generalization in the Bucegi Mountains and it has an insular character and a tentacular one in the area of the sheepfolds and chalets, as well as of the alpine roads, of the intensely used tourist paths.
Knowing the alpine area of the Transylvanian Alps very well, we conclude that the building of the roads in the alpine area is by far the most dangerous way of human intervention in the geomorphological landscape.An instructive example is the building of the Transfăgărăşan road, where in their connected area the morphogenetic conditions were changed, with the emergence of new cliffs.This situation associated with the vibrations induced by the traffi c, favours frost weathering, rock falling and rolling -with the appearance of talus cones and versants of frost-crumbled blocks.In the area with intensive and chaotic tourist paths network and also in the intensive pasturage areas, which bring about the destruction of the bush and herbaceous vegetation, vertical erosion associated with ravines, gullies and torrents, is very typical of the conglomerate area in the Bucegi Mountains and also of the area with thick soils and soft rocks.