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Powerpoint TemplatesPage 1
Landforms and the shaping of cultural landscapes in mountain areas A methodology for the analysis of permanent pastures landscape of Alto Barroso region (Northern Portugal)
17th International Symposium “Landscape and Landscape Ecology”27 – 29 May, 2015, Nitra, Slovakia
Andreia Pereira – [email protected] Phd student in Physical Geography in the University of Coimbra /
Centre of Studies on Geography and Spatial Planning (CEGOT), Portugal
Powerpoint TemplatesPage 2
Research goals
Analyse how major terrain features and medium scale landforms, as well as the lithological formations, played a key role in the organization of the
soil use pattern in Alto Barroso
Identify and characterize the landforms with major interest for
landscape interpretation
Define the conditions of the distribution of the different types of
permanent grasslands, with particular emphasis in the morphostructural
factors
Promote the acknowledgment of the landscape and productive values of
the landforms and their potential heritage interest
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LandformHistorical /cultural / economical value
Scientific / didactic value
Results from the
combination of geo-
structural and
morphogenetic factors
Conditioning factor Testifies
Land-use options and strategic use of
resources
Functional appropriation of the
resources associated to landforms
Morphogenetic processes that took
place in paleoenvironments,
the tectonic action and the present dynamics
Understanding of geomorphological heritage as a an
evidence from the past and present
geomorphologic processes
Understanding of geomorphological
heritage as an evidence of Man – Nature interactions
Landforms are a crucial variable in land planning, territory management and development strategies
Dimensions and values of the geomorphologic heritage
Alto Barroso: morphostructural framework
Climograph of Montalegre
Pre
cipi
tatio
n (m
m)
Tem
pera
ture
(ºC
)
Temperature (ºC)Precipitation (mm)
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What defines the landscape character in Alto Barroso?
Morphological features of a table land• Importance of the plateaus, entrenched valleys, grabens and natural terraces in the distribution of the
soil uses
Specific characteristics of a multi-century old agro-pastoral system• Cattle breading, based on extensive grazing, as the main regional production• Cultivation of poor dryland cereals at high altitudes• Association of poor mountain pastures and water-meadows (semi-artificial permanent grasslands)• Introduction of the water-meadows during the Upper Medieval Ages, simultaneously with the creation
of the mountain villages (Moreira et al. 2001; Taborda 1932)• Ancestral agro-pastoral techniques and practices (surface irrigation, grasslands in terraces,
communitarianism)• Preserved groves of broadleaves, especially oaks• Delimitation of the pastures by broadleaves
Concentrated settlement • Share of collective structures (threshing floors, oil mills, ovens) • Vernacular architecture• Use of local construction materials
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Agro-silvo-pastoral cultural landscape: a dynamic system • The morphological profile of a typical slope in Alto Barroso corresponds to
a specific pattern of distribution of land uses, whose sequence in altitude is determined by the variation of soil properties, water availability and slope.
• The forest and shrublands, the poor mountain pastures, the water-meadows, the upland cereal cultures and the extensive horticulture build a landscape mosaic sustained by an intricate network of functional interdependencies and complementarities.
Mountain grasslands and permanent pastures
Environmentalfunctions
Economic functions
Cattle Breeding (autochthonous bovines)
Regulation of the water cicle
Aestetic value
Increase of the diversity of landscape mosaic
Past Present
Labour force Bovine meat of high quality
Manure
Seed potatoes
Upland Cereals
Watering crops Fauna and flora biodiversity
Soil formation and protection
Control of wildfires spread
Tourism Resource
Infiltration / Accumulation
Recharging of the groundwater tables
Decrease of the soil erosion risk
Decrease of pipkrakes formation
LandscapeValue
Pastures
A cultural landscape that reflects the adaptation strategies to environmental constraints• The need to overcome the specific soil and climatic constraints of
mountain environments, aiming to enable the practice of agriculture and increase its productivity, led to the development of several strategies of water management and soil conservation, among which we must highlight:– the agro-pastoral terraces, with or without supporting walls; – the traditional irrigation systems, the practice of specific techniques
of “superficial irrigation” (“rega de lima”);– The incorporation of manure in the grasslands;– The communitarian management of some resources (irrigation water,
common lands) and agro-pastoral activities (shepherding), and structures / equipments
Sampaio (1979) states that in the Barroso "... the pastoral regimen becomes so prevalent that, without exaggeration, one can say that the population lives mainly of the herds, which in a large part of the year are breed in the rich pastures of the hills and the collective use of the neighbors".
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“Rega de Lima”• “Rega de Lima” is an ancient watering technique that is
based in a drainage system used to channel the water from small streams to slope ditches (locally named “regueiras”), following the contour lines.
• These ditches drain the irrigation water to the grasslands, allowing it to slowly flow over the soil trough a controlled runoff, producing a “lime effect”.
• Then, the ditches placed in a lower level collect the flowing water, reproducing the same process. In a final stage, the water returns to the stream.
• It is frequently observed the presence of a network of draining grooves linked to the ditches system, which enables a more uniform distribution of the water, preventing dry or flooded areas.
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Methodology• The assessment of potential geomorphological heritage was
conducted at a regional scale, within the framework of Alto Barroso;
• The main selection criteria reflects the relation between landforms and landscape structure.
Geomorphological analysis
• Field work• Morphostructural outline• Identification of the major terrain features and medium scale landforms
Homogeneous terrain units
• Morphologic factors• Morphodynamics• Landscape Perception•Adaptation of the geomorphological map to landscape reading
Correlation of landforms with the soil use pattern
• Distribution of the different types of permanent grasslands,
• Interrelation between the geomorphology and the landscape organization
Selected landforms: insertion in the regional morphology
Lithological diversity
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Morphostructure, landforms and soil use
Complementarity between different types of grasslands
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Water-meadows: location factors• Water-meadows occupy preferentially fields with high water
availability and fine textured soils with elevated organic matter content which, when soaked and with no vegetation cover, are abundant in mud, which will feature at the origin of the designation as "lameiros", a word that refers to a muddy grassland (Vieira et al., 2000; Pereira & Sousa, 2005).
• Therefore, they occur mainly on granitic substrates and on hillsides with slopes that goes from smooth to average gradient, so as to ensure a good drainage.
• The high amount of annual rainfall, associated with deep granitic alteration mantles, explain the great water availability, constituting a favorable factor to the implementation of water-meadows.
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Distribution of the permanent pastures over the main lithological groups
Lithological groups
Area (Km2)Area of the permanent
pastures Km2
% in relation to the total area of permanent
pastures
% of occupation of
the permanent pastures of the
area of the lithological
group
Granitic rocks 541,99 203,78 53,83 37,59
Schales 385,09 116,48 30,77 30,25
Paragnaiss 100,54 55,53 14,67 55,23
Others 37,16 2,75 0,73 7,40
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Percent of the soil use calculated in relation to the area of each landform
A Water-meadows; B Poor mountain grasslands; C Forest and shrublands; D Shrubby and sub-shrubby vegetation; E Scarce vegetation cover; F Complex agricultural areas; G Permanent cultures; H Annual cultures; I Built area.
Soil use area in %Landforms A B C D E F G H I
Valley of Aires River 32,9 28,7 15,6 15,6 0,0 1,4 0,0 5,4 0,1Upper Valley of Rabagão
River 43,7 16,6 2,77 16,3 2,7 9,7 0,1 4,4 3,4
Upper Valley of Cávado River 43,5 19,6 10,8 11,4 1,6 5,3 0,0 6,3 1,2
Upper Valley of Beça River 50,1 14,4 3,0 17,7 0,1 7,5 0,0 6,9 0,03
Middle Valley of Beça River 19,0 40,7 17,6 12,9 0,0 8,0 0,1 1,6 0,0
Lower Valley of Beça River 48,7 13,1 17,2 7,33 0,0 10,2 0,0 1,7 1,4Upper Valley of Assureira
River 33,0 2,4 10,2 8,1 26,2 6,6 0,0 12,1 1,1
Graben of Rabagão 27,3 12,8 15,0 10,6 0,6 4,2 0,0 27,4 1,7Graben of Dornelas 25,2 11,0 8,5 9,5 0,2 30,0 0,0 9,1 6,3Graben of Boticas 14,3 1,7 16,1 2,1 0,0 35,2 0,0 0,0 30,4Graben of Ardãos 30,5 14,4 7,2 13,6 0,00 24,4 0,0 6,9 2,8Graben of Amial 36,9 20,1 12,3 2,3 3,1 8,1 0,0 14,6 2,4Range of Seixa 3,4 6,1 39,7 43,3 3,8 2,1 0,0 0,4 0,8Range of Leiranco 0,2 15,4 2,2 79,9 0,9 0,4 0,0 0,1 0,5Range of Larouco 0,9 6,1 2,1 21,4 68,3 0,9 0,0 0,1 0,0Range of Cerdeira 7,3 19,4 18,7 45,1 1,8 2,0 0,0 4,9 0,4Range of Barroso 5,8 7,1 2,7 61,7 20,5 1,5 0,0 0,4 0,0Plateau of Pitões 11,0 44,4 5,6 30,7 4,9 1,2 0,0 1,8 0,3Plateau of Alturas 34,6 28,9 6,4 19,6 1,3 3,4 0,1 5,3 0,4Natural terrace of Solveira 10,5 18,9 2,5 20,5 4,8 5,1 1,5 35,0 2,2
Natural terrace of Pinho 11,0 0,1 29,5 26,9 0,00 30,1 0,0 0,3 1,9
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Landforms and the distribution of permanent grasslands and croplands
• Landforms may be divided in three groups according to the importance of the water-meadows and the poor mountain grasslands:1st - landforms with more than 50% of their area
occupied by permanent grasslands. In this group the valleys and uplands are dominant. Only the graben of Amial is inserted here.
2nd - landforms with 25% to 50% of their area occupied by permanent grasslands. In this group, the grabens are more representative.
3rd - the permanent grasslands represent less than 20% of the area of the landform. Here, there is a clear dominance of the mountain and hilly areas.
Contrast between the upper valley of Cávado river and the plateau of Pitões
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Morphological characterization of each landform and its relation with
soil use
LandformAreaKm2
Morphologic features
Main morphogenetic
process
Most relevant soil uses
Upper Valley of Rabagão River 43,02
Slope <8º; Minimum elevation - 870; Maximum elevation - 1168
Fluvial dynamicsProbably tectonic action at the northern sector leading to the formation of a graben.
Water-meadows: 43,75% Mountain grasslands 16,69% Low shrubs 16,36%
Upper Valley of Cávado River 33,63
Slope <11º; Minimum elevation - 750; Maximum elevation - 1021
Fluvial dynamicsFracture valley corresponding to a complex tectonic depression (graben)
Water-meadows 43,52% Mountain grasslands 19,67%
Valleys: clear dominance of water-meadows
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Grabens: dominance of water-meadows and croplands
LandformAreaKm2
Morphologic features
Main morphogenetic
process
Most relevant soil uses
Graben of Amial
7,76Slope <8º; Minimum elevation - 810; Maximum elevation - 930
Tectonic depressionWater-meadows 36,91%Mountain grasslands 20,16%
Graben of Rabagão
4,27Slope <11º; Minimum elevation - 700; Maximum elevation - 810
Tectonic depressionFluvial dynamics
Water-meadows 27,34% Annual cultures 27,45% Forest/shrublands 15,03%
Graben of Dornelas
3,12Slope <8º; Minimum elevation - 650; Maximum elevation - 734
Tectonic depressionWater-meadows 25,29%Complex agricultural systems 30,00%
LandformAreaKm2
Morphologic features
Main morphogenetic
process
Most relevant soil uses
Plateau of Pitões
96,12Slope 2º-11º;
Minimum elevation - 900; Maximum elevation - 1401
Complex horst; Fluvial dynamics
associated to fracture valleys
Mountain grasslands 44,47% Low shrubs
30,79%
Plateau of Alturas
60,93Slope <11º; Minimum
elevation - 810; Maximum elevation - 1229
Tectonic action leading to a elevated block (horst)
Fluvial dynamics
Water-meadows 34,60% Mountain grasslands 28,90% Low shrubs
19,61%
Plateaus: dominance of mountain grasslands, water-meadows and low shrubs
Relation between the landforms and the distribution pattern of the permanent grasslands• The water-meadows and the poor mountain grasslands
have more than a half of their area concentrated within the identified landforms. This strong correlation has no parallel when we look to the other soil uses: none of them reaches 50%.
• The water-meadows are predominantly located on valleys and grabens, as well as in plateaus when the hydrogeological and pedologic conditions are appropriated.
• The highest percent of the area of water-meadows at a regional scale is distributed by the plateau of Alturas, the upper valleys of the rives Rabagão, Cávado and Beça and the graben of Amial.
• The plateau of Pitões is the landform that concentrate the biggest area of poor mountain grasslands, followed by the plateau of Alturas.
From the relation landforms/landscape to the selection of geomorphosites• The upper valleys of Cávado, Rabagão and Beça rivers, the
plateaus of Pitões and Alturas and the graben of Amial proved to be the landforms that conciliate a greater landscape and productive values.
• They may be classified as sites of geomorphological interest at a regional scale, which heritage value should be protected, by the inclusion of preservation measures in the territorial management instruments, by monitoring land use changes and its drivers, as well as by encouraging the maintenance of the traditional cattle breeding practices.
• This approach highlights the heritage value of eco-sociologic systems that express multi-century old strategies of Man adaptation of environmental conditions and promote its use as a differentiation factor in sustainable development marketing (local products certification with Protected Designation of Origin / Protected Geographical Indication; cultural and landscape touring.)
Be welcome to Alto Barroso!