Holocene acidiﬁ cation process recorded in three pollen proﬁ les from Czech sandstoneand river terrace environments

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P. Pokorný & P. Kuneš Holocene acidiﬁ cation process recorded in pollen proﬁ les, Czech Republic

Holocene acidiﬁ cation process recorded in three pollen proﬁ les from Czech sandstone and river terrace environments

Petr POKORNÝ Institute of Archaeology, Academy of Sciences of the Czech Republic

Letenská 4, CZ-118 01 Praha 1 Institute of Archaeology, Academy of Sciences of the Czech Republic Letenská 4, CZ-118 01 Praha 1 Institute of Archaeology, Academy of Sciences of the Czech Republic pokorny@arup.cas.cz Petr KUNEŠ Department of Botany, Charles University in Prague Benátská 2, CZ-128 01 Praha 2 Department of Botany, Charles University in Prague Benátská 2, CZ-128 01 Praha 2 Department of Botany, Charles University in Prague cuneus@natur.cuni.cz

Introduction

Late Quaternary climatic changes had dramatic eff ect on the terrestrial biosphere. In temperate Late Quaternary climatic changes had dramatic eff ect on the terrestrial biosphere. In temperate Late Quaternary climatic changes had dramatic mid-latitude regions of the Northern Hemisphere, eff ect on the terrestrial biosphere. In temperate mid-latitude regions of the Northern Hemisphere, eff ect on the terrestrial biosphere. In temperate vegetation belts migrated over several thousands mid-latitude regions of the Northern Hemisphere, vegetation belts migrated over several thousands mid-latitude regions of the Northern Hemisphere, of kilometers. These macroscale vegetational vegetation belts migrated over several thousands of kilometers. These macroscale vegetational vegetation belts migrated over several thousands changes were accompanied (and were partly in of kilometers. These macroscale vegetational changes were accompanied (and were partly in of kilometers. These macroscale vegetational response to) changes in soil properties. The ways in changes were accompanied (and were partly in response to) changes in soil properties. The ways in changes were accompanied (and were partly in which soil-vegetation relationships have evolved, response to) changes in soil properties. The ways in which soil-vegetation relationships have evolved, response to) changes in soil properties. The ways in and particularly the response of vegetational and which soil-vegetation relationships have evolved, and particularly the response of vegetational and which soil-vegetation relationships have evolved, pedogenetic processes to climatic change, are of and particularly the response of vegetational and pedogenetic processes to climatic change, are of and particularly the response of vegetational and fundamental importance in understanding the pedogenetic processes to climatic change, are of fundamental importance in understanding the pedogenetic processes to climatic change, are of dynamics of contemporary ecosystems. Viewed fundamental importance in understanding the dynamics of contemporary ecosystems. Viewed fundamental importance in understanding the in this light, acidifi cation is a long-term natural dynamics of contemporary ecosystems. Viewed in this light, acidifi cation is a long-term natural dynamics of contemporary ecosystems. Viewed process that occurs especially during warm phases in this light, acidifi cation is a long-term natural process that occurs especially during warm phases in this light, acidifi cation is a long-term natural of Quaternary climatic cycle (Iversen 1958; Birks process that occurs especially during warm phases of Quaternary climatic cycle (Iversen 1958; Birks process that occurs especially during warm phases 1986). It is characterized by loss of cations (namely of Quaternary climatic cycle (Iversen 1958; Birks 1986). It is characterized by loss of cations (namely of Quaternary climatic cycle (Iversen 1958; Birks bivalent bases - Ca

1986). It is characterized by loss of cations (namely bivalent bases - Ca

1986). It is characterized by loss of cations (namely 1986). It is characterized by loss of cations (namely 2+

1986). It is characterized by loss of cations (namely 2+

and Mg

1986). It is characterized by loss of cations (namely and Mg

1986). It is characterized by loss of cations (namely 1986). It is characterized by loss of cations (namely 2+

1986). It is characterized by loss of cations (namely 2+

) that are normally 1986). It is characterized by loss of cations (namely ) that are normally 1986). It is characterized by loss of cations (namely bound to clay minerals in the soils. Under wet and and Mg bound to clay minerals in the soils. Under wet and and Mg ) that are normally bound to clay minerals in the soils. Under wet and ) that are normally warm conditions, bases are leached from these bound to clay minerals in the soils. Under wet and warm conditions, bases are leached from these bound to clay minerals in the soils. Under wet and complexes, being dissolved in percolating water and transported out of the ecosystem (and fi nally complexes, being dissolved in percolating water and transported out of the ecosystem (and fi nally complexes, being dissolved in percolating water through the rivers to the sea). This process results and transported out of the ecosystem (and fi nally through the rivers to the sea). This process results and transported out of the ecosystem (and fi nally in change in species composition and produc- through the rivers to the sea). This process results in change in species composition and produc- through the rivers to the sea). This process results tivity of the ecosystems. The dynamics of acidifi - in change in species composition and productivity of the ecosystems. The dynamics of acidifi - in change in species composition and produc- cation is seriously modifi ed by climatic changes, tivity of the ecosystems. The dynamics of acidifi - cation is seriously modifi ed by climatic changes, tivity of the ecosystems. The dynamics of acidifi - biotic infl uences, and, during the Holocene, also cation is seriously modifi ed by climatic changes, biotic infl uences, and, during the Holocene, also cation is seriously modifi ed by climatic changes, by human intervention (Bell & Walker 1992).

biotic inﬂ uences, and, during the Holocene, also by human intervention (Bell & Walker 1992).

biotic inﬂ uences, and, during the Holocene, also Antropogenic activities contribute to the acidi- by human intervention (Bell & Walker 1992).

Antropogenic activities contribute to the acidi- by human intervention (Bell & Walker 1992).

fi cation through removal of biomass (grazing, Antropogenic activities contribute to the acidifi cation through removal of biomass (grazing, Antropogenic activities contribute to the acidi- mowing, woodcu� ing, harvesting without subse- fi cation through removal of biomass (grazing, mowing, woodcu� ing, harvesting without subse- fi cation through removal of biomass (grazing, quent manuring) and through triggering the soil mowing, woodcu� ing, harvesting without subsequent manuring) and through triggering the soil mowing, woodcu� ing, harvesting without subse- erosion. Positive backbound mechanisms may quent manuring) and through triggering the soil erosion. Positive backbound mechanisms may quent manuring) and through triggering the soil play an important role in case of biological control erosion. Positive backbound mechanisms may play an important role in case of biological control erosion. Positive backbound mechanisms may of acidifi cation. To give a simple example from play an important role in case of biological control of acidifi cation. To give a simple example from play an important role in case of biological control Central Europe: At the fi rst stage of acidifi cation, of acidifi cation. To give a simple example from Central Europe: At the fi rst stage of acidifi cation, of acidifi cation. To give a simple example from coniferous trees (namely

Central Europe: At the ﬁ rst stage of acidiﬁ cation, coniferous trees (namely

Central Europe: At the ﬁ rst stage of acidiﬁ cation, Pinus sylvestris, Picea abies, and coniferous trees (namely

and coniferous trees (namely

Abies alba) spread within broadleaf forests.

coniferous trees (namely

) spread within broadleaf forests.

coniferous trees (namely Pinus sylvestris

) spread within broadleaf forests. Pinus sylvestris

During the decomposition of coniferous falloﬀ , humic acids are produced in great quantities.

Organic compounds in soils change from mull to mor humus. This effi ciently speeds up further acidifi cation and soils structure is changed in the process called podzolisation. Usually also upper layer of underlying bedrock is being leached and decalcifi ed.

Due to its long long-term nature, acidiﬁ cation processes can be best studied in secular to millennial time scale. Pollen analysis is appro- priate tool for this as it enables to record time scales long enough and because vegetation corresponds directly to local geochemical changes.

The pollen and sediment chemistry evidence

Soils developed on relatively acidic bedrock are o� en more sensitive to loss of nutrients than those on calcareous substrata. This is why best evidence for Holocene acidifi cation in the Czech Republic comes from sandstone regions and from river environment with extensive cover of acidic sands and gravel. In the following, we will give three examples of profi les, where acidifi cation process can be studied (location of profi les indicated in Fig. 1).

Anenské údolí, Broumovsko sandstone region

The site, a topogenic mire in the bo� om of a valley at 645 m a.s.l. altitude, is surrounded by dramatic

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108 Ferrantia • 44 / 2005

relief with sandstone rocks and gorges. Present vegetation is dominated by acidic pine woodland in relatively dryer situations and by spruce planta- vegetation is dominated by acidic pine woodland in relatively dryer situations and by spruce planta- vegetation is dominated by acidic pine woodland tions in the bo� oms of the valleys. Climate of the in relatively dryer situations and by spruce planta- tions in the bo� oms of the valleys. Climate of the in relatively dryer situations and by spruce planta- region is oceanic and relatively cold (mean annual tions in the bo� oms of the valleys. Climate of the region is oceanic and relatively cold (mean annual tions in the bo� oms of the valleys. Climate of the temperature around 7°C and rainfall around 800 region is oceanic and relatively cold (mean annual temperature around 7°C and rainfall around 800 region is oceanic and relatively cold (mean annual mm).

In the pollen diagram (Fig. 2) we see gradual vegetation change from mixed oak woodlands to In the pollen diagram (Fig. 2) we see gradual vegetation change from mixed oak woodlands to In the pollen diagram (Fig. 2) we see gradual communities dominated by spruce (Picea abies), beech (

communities dominated by spruce ( beech (

communities dominated by spruce ( Fagus sylvatica), and silver ﬁ r ( communities dominated by spruce (

), and silver ﬁ r ( communities dominated by spruce (

Abies alba).

This change can be observed between 150 and 85 cm – i.e. between ca 4 100 and 3 400 B.P. according to radiocarbon chronology. While the decrease in demanding tree species is gradual, expansion of to radiocarbon chronology. While the decrease in demanding tree species is gradual, expansion of to radiocarbon chronology. While the decrease in constituents of oligotrophic woodland communities demanding tree species is gradual, expansion of constituents of oligotrophic woodland communities demanding tree species is gradual, expansion of is stepwise: In the fi rst step this is the expansion constituents of oligotrophic woodland communities is stepwise: In the fi rst step this is the expansion constituents of oligotrophic woodland communities of is stepwise: In the fi rst step this is the expansion of is stepwise: In the fi rst step this is the expansion

Picea abies, followed by strong increase in is stepwise: In the ﬁ rst step this is the expansion

, followed by strong increase in is stepwise: In the ﬁ rst step this is the expansion

Fagus sylvatica and , followed by strong increase in

and , followed by strong increase in Abies alba. Also hornbeam ( , followed by strong increase in

. Also hornbeam ( , followed by strong increase in

Carpinus betulus) appears in this stage. As human impact indicators virtually lacking in the pollen record we ) appears in this stage. As human impact indicators virtually lacking in the pollen record we ) appears in this stage. As human impact may assume that above-described process of acidi- indicators virtually lacking in the pollen record we may assume that above-described process of acidi- indicators virtually lacking in the pollen record we

ﬁ cation was controlled entirely by natural inﬂ u- ences in this case.

fi cation was controlled entirely by natural infl u- To get more insight to process of acidifi cation, samples for chemical analysis of Ca

To get more insight to process of acidiﬁ cation, samples for chemical analysis of Ca

To get more insight to process of acidiﬁ cation, To get more insight to process of acidiﬁ cation, 2+

To get more insight to process of acidiﬁ cation, 2+

and Mg To get more insight to process of acidiﬁ cation,

and Mg To get more insight to process of acidiﬁ cation, To get more insight to process of acidiﬁ cation, 2+

To get more insight to process of acidiﬁ cation, 2+

cations (Fig. 5) were taken directly from above- samples for chemical analysis of Ca

described peat profi le. At fi rst, concentration of cations (Fig. 5) were taken directly from above- described peat profi le. At fi rst, concentration of cations (Fig. 5) were taken directly from above- both elements steadily rises (from about 190 to 95 described peat profi le. At fi rst, concentration of both elements steadily rises (from about 190 to 95 described peat profi le. At fi rst, concentration of cm). This must be the result of increased leaching both elements steadily rises (from about 190 to 95 cm). This must be the result of increased leaching both elements steadily rises (from about 190 to 95 from the soils in the catchment a� er invasion of cm). This must be the result of increased leaching from the soils in the catchment a� er invasion of cm). This must be the result of increased leaching beech (Fagus sylvatica). Leached cations were than bound into peat organic ma� er (Digerfeldt 1972).

Maximum concentrations are found at the level of 95 bound into peat organic ma� er (Digerfeldt 1972).

cm – this is probably the result of silver fi r invasion (see Abies alba curve in pollen diagram). As already cm – this is probably the result of silver fi r invasion curve in pollen diagram). As already cm – this is probably the result of silver fi r invasion described above, the decomposition of coniferous curve in pollen diagram). As already described above, the decomposition of coniferous curve in pollen diagram). As already falloff may speed up acidifi cation process. Spread described above, the decomposition of coniferous falloff may speed up acidifi cation process. Spread described above, the decomposition of coniferous of coniferous forest in the catchment caused more falloff may speed up acidifi cation process. Spread of coniferous forest in the catchment caused more falloff may speed up acidifi cation process. Spread Ca²⁺ and Mg²⁺ to be released from the soils. A� er the maximum at 95 cm, the concentrations of both and Mg the maximum at 95 cm, the concentrations of both and Mg Ca²⁺ and Mg²⁺ started to decline as their availability slowly decreased in the catchment. At this time started to decline as their availability slowly decreased in the catchment. At this time started to decline as their availability fi nally, acidifi cation process was completed.

slowly decreased in the catchment. At this time ﬁ nally, acidiﬁ cation process was completed.

slowly decreased in the catchment. At this time Fig. 1: Territory of the Czech Republic and the location of sites and regions mentioned in the text.

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Jelení louže, České Švýcarsko sandstone region

This pollen profi le comes from a topogenic mire that is situated in relatively shallow sandstone gorge, about 400 m a.s.l. The site is surrounded by large sandstone plateau bordered by well- developed rock formations. Today, this area is extremely acidic with species-poor vegetation dominated by pine and birch. Surface pollen spectrum (0 cm in the pollen profi le) refl ects the present vegetation conditions. Local climate is rather oceanic with relatively high annual rainfall (nearby station at Chřipská: 934 mm).

Acidiﬁ cation process is seen in the pollen diagram between the depth of 210 and 120 cm (Fig. 3).

This corresponds to the time period between about 4700 B.P. and 2900 B.P. according to radiocarbon dating. As in the case of Anenské údolí site, although ﬁ nal consequences of acidiﬁ cations are very deep, the process itself is rather gradual.

Vegetation response to acidifi cation has a stepwise character. The starting point is the vegetation of rich mixed oak woodlands with signifi cant admixture of hazel (Corylus avelana). In the fi rst step, the curves of demanding trees (Quercus, Tilia, Ulmus, Acer, Acer, Acer Fraxinus, and Corylus) decline in

favor to expanding beech (Fagus sylvatica). During the second step we may observe another decrease favor to expanding beech (

the second step we may observe another decrease favor to expanding beech (Fagus sylvatica

the second step we may observe another decrease Fagus sylvatica). During the second step we may observe another decrease ). During in demanding broadleaf trees, but also the decline the second step we may observe another decrease in demanding broadleaf trees, but also the decline the second step we may observe another decrease in Fagus that is replaced by silver ﬁ r (

in demanding broadleaf trees, but also the decline that is replaced by silver ﬁ r (

in demanding broadleaf trees, but also the decline Abies alba).

In the same period, anthropogenic indicators are that is replaced by silver fi r ( In the same period, anthropogenic indicators are that is replaced by silver fi r ( very low in the pollen diagram, excluding again In the same period, anthropogenic indicators are very low in the pollen diagram, excluding again In the same period, anthropogenic indicators are the possibility of anthropogenic control of acidifi - very low in the pollen diagram, excluding again the possibility of anthropogenic control of acidifi - very low in the pollen diagram, excluding again cation process.

Tišice, middle Labe region

Unlike the previous two cases, this site is situated at low elevation (165 m a.s.l.) and in very diff erent Unlike the previous two cases, this site is situated at low elevation (165 m a.s.l.) and in very diff erent Unlike the previous two cases, this site is situated geomorphologic situation - in a fl at landscape at low elevation (165 m a.s.l.) and in very diff erent geomorphologic situation - in a fl at landscape at low elevation (165 m a.s.l.) and in very diff erent within a broad valley of Labe River, adjacent geomorphologic situation - in a fl at landscape within a broad valley of Labe River, adjacent geomorphologic situation - in a fl at landscape to Polomené hory sandstone area. The valley is within a broad valley of Labe River, adjacent to Polomené hory sandstone area. The valley is within a broad valley of Labe River, adjacent fi led with sandy and gravel substrata of Pleis- to Polomené hory sandstone area. The valley is fi led with sandy and gravel substrata of Pleis- to Polomené hory sandstone area. The valley is tocene river terraces. We may trace the history of fi led with sandy and gravel substrata of Pleis- tocene river terraces. We may trace the history of fi led with sandy and gravel substrata of Pleis- human impact in the region deep into Neolithic tocene river terraces. We may trace the history of human impact in the region deep into Neolithic tocene river terraces. We may trace the history of period from the pollen-analytical investigations human impact in the region deep into Neolithic period from the pollen-analytical investigations human impact in the region deep into Neolithic and according to archaeological excavations period from the pollen-analytical investigations and according to archaeological excavations period from the pollen-analytical investigations (Dreslerová & Pokorný 2004). Today, this is an and according to archaeological excavations (Dreslerová & Pokorný 2004). Today, this is an and according to archaeological excavations agricultural landscape with some li� le remains of (Dreslerová & Pokorný 2004). Today, this is an agricultural landscape with some li� le remains of (Dreslerová & Pokorný 2004). Today, this is an acidic pine woodlands. Local climate is warm, dry, agricultural landscape with some li� le remains of acidic pine woodlands. Local climate is warm, dry, agricultural landscape with some li� le remains of and relatively continental (mean annual climatic acidic pine woodlands. Local climate is warm, dry, and relatively continental (mean annual climatic acidic pine woodlands. Local climate is warm, dry, characteristics of nearby city of Mělník: 8.7 °C, 527 and relatively continental (mean annual climatic characteristics of nearby city of Mělník: 8.7 °C, 527 and relatively continental (mean annual climatic mm).

Fig. 2: Simpliﬁ ed percentage pollen diagram from Anenské údolí site. The period of acidiﬁ cation indicated at right.

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110 Ferrantia • 44 / 2005

Older part of the pollen diagram (Fig. 4) is characterized by high pollen curves of

Older part of the pollen diagram (Fig. 4) is charac- Quercus, Tilia, Ulmus, Fraxinus, and

terized by high pollen curves of , and

terized by high pollen curves of

Corylus. Acidiﬁ cation is terized by high pollen curves of

. Acidiﬁ cation is terized by high pollen curves of

much more dramatic process than in previous two Corylus much more dramatic process than in previous two Corylus examples. It is seen in pollen diagram as sudden much more dramatic process than in previous two examples. It is seen in pollen diagram as sudden much more dramatic process than in previous two vegetation change between 185 and 175 cm depth.

examples. It is seen in pollen diagram as sudden vegetation change between 185 and 175 cm depth.

examples. It is seen in pollen diagram as sudden This period corresponds roughly to 3 000 B.P.

vegetation change between 185 and 175 cm depth.

This period corresponds roughly to 3 000 B.P.

vegetation change between 185 and 175 cm depth.

according to radiocarbon chronology. Demanding This period corresponds roughly to 3 000 B.P.

trees of mixed oak woodlands decline in this point according to radiocarbon chronology. Demanding trees of mixed oak woodlands decline in this point according to radiocarbon chronology. Demanding and curves of

trees of mixed oak woodlands decline in this point and curves of

trees of mixed oak woodlands decline in this point Pinus and

trees of mixed oak woodlands decline in this point and

trees of mixed oak woodlands decline in this point Abies alba increase signiﬁ - trees of mixed oak woodlands decline in this point

increase signifi - trees of mixed oak woodlands decline in this point cantly. This event is synchronous with sudden increase signifi - cantly. This event is synchronous with sudden increase signifi - rise in antropogenic indicators – both arable cantly. This event is synchronous with sudden rise in antropogenic indicators – both arable cantly. This event is synchronous with sudden and grazing indicators. Close correlation of both rise in antropogenic indicators – both arable and grazing indicators. Close correlation of both rise in antropogenic indicators – both arable phenomena suggests an anthropogenic control of and grazing indicators. Close correlation of both phenomena suggests an anthropogenic control of and grazing indicators. Close correlation of both acidifi cation process. This was probably the reason phenomena suggests an anthropogenic control of acidifi cation process. This was probably the reason phenomena suggests an anthropogenic control of why vegetation change is so sharp in this case.

acidiﬁ cation process. This was probably the reason why vegetation change is so sharp in this case.

acidiﬁ cation process. This was probably the reason

Discussion and conclusions

Sandstone and river terrace landscapes in the Czech Republic experienced considerable changes Sandstone and river terrace landscapes in the Czech Republic experienced considerable changes Sandstone and river terrace landscapes in the in their productivity, species richness and compo- Czech Republic experienced considerable changes in their productivity, species richness and compo- Czech Republic experienced considerable changes sition during the Late Holocene. These areas, today in their productivity, species richness and composition during the Late Holocene. These areas, today in their productivity, species richness and compo- extremely acidic and oligotrophic, were much sition during the Late Holocene. These areas, today extremely acidic and oligotrophic, were much sition during the Late Holocene. These areas, today

more nutrient rich during most of their Holocene history. In the example of three pollen profi les we more nutrient rich during most of their Holocene history. In the example of three pollen profi les we more nutrient rich during most of their Holocene could see how process of acidifi cation may diff er history. In the example of three pollen profi les we could see how process of acidifi cation may diff er history. In the example of three pollen profi les we in the timing and in its dynamics. These diff er- could see how process of acidifi cation may diff er in the timing and in its dynamics. These diff er- could see how process of acidifi cation may diff er ences are due to diff erent local climatic se� ing in the timing and in its dynamics. These diff er- ences are due to diff erent local climatic se� ing in the timing and in its dynamics. These diff er- and, more important, due to diff erent human ences are due to diff erent local climatic se� ing and, more important, due to diff erent human ences are due to diff erent local climatic se� ing impact histories.

and, more important, due to diﬀ erent human impact histories.

and, more important, due to diff erent human First evidence for Late Holocene acidifi cation of Czech sandstone landscapes was given by V. Ložek (1998). His arguments are based on of Czech sandstone landscapes was given by V. Ložek (1998). His arguments are based on of Czech sandstone landscapes was given by palaeomalacological fi nds from sedimentary V. Ložek (1998). His arguments are based on palaeomalacological fi nds from sedimentary V. Ložek (1998). His arguments are based on fi lls of rock shelters at Polomené hory sandstone palaeomalacological fi nds from sedimentary fi lls of rock shelters at Polomené hory sandstone palaeomalacological fi nds from sedimentary area. Middle Holocene snail communities were fi lls of rock shelters at Polomené hory sandstone area. Middle Holocene snail communities were fi lls of rock shelters at Polomené hory sandstone surprisingly rich in species, whereas at present the areas in question are characterized by only surprisingly rich in species, whereas at present the areas in question are characterized by only surprisingly rich in species, whereas at present very poor communities consisting of few most the areas in question are characterized by only very poor communities consisting of few most the areas in question are characterized by only resistant species. Strong decrease in snail species very poor communities consisting of few most resistant species. Strong decrease in snail species very poor communities consisting of few most richness – from 41 species to only 6 in case of a resistant species. Strong decrease in snail species richness – from 41 species to only 6 in case of a resistant species. Strong decrease in snail species single site - coincides with the Final Bronze Age richness – from 41 species to only 6 in case of a single site - coincides with the Final Bronze Age richness – from 41 species to only 6 in case of a period (about 3 000 B.P.). This suggests a dramatic single site - coincides with the Final Bronze Age period (about 3 000 B.P.). This suggests a dramatic single site - coincides with the Final Bronze Age transformation of ecosystem during respective period (about 3 000 B.P.). This suggests a dramatic transformation of ecosystem during respective period (about 3 000 B.P.). This suggests a dramatic time. For the explanation of this phenomenon, transformation of ecosystem during respective time. For the explanation of this phenomenon, transformation of ecosystem during respective Ložek proposes model of environmental collapse time. For the explanation of this phenomenon, Ložek proposes model of environmental collapse time. For the explanation of this phenomenon, induced by climatic change associated with Ložek proposes model of environmental collapse induced by climatic change associated with Ložek proposes model of environmental collapse human activity - woodland clearance and grazing.

induced by climatic change associated with human activity - woodland clearance and grazing.

induced by climatic change associated with This model corresponds very well to our present human activity - woodland clearance and grazing.

This model corresponds very well to our present human activity - woodland clearance and grazing.

Fig. 3: Simpliﬁ ed percentage pollen diagram from the Jelení louže site. The period of acidiﬁ cation is indicated on the right side.

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data from Tišice site, where vegetation change to more acidic conditions is synchronous with signif- data from Tišice site, where vegetation change to more acidic conditions is synchronous with signif- data from Tišice site, where vegetation change to icant increase in human impact. Also the timing of more acidic conditions is synchronous with signif- icant increase in human impact. Also the timing of more acidic conditions is synchronous with signif- both acidifi cation events is about the same (Late icant increase in human impact. Also the timing of both acidifi cation events is about the same (Late icant increase in human impact. Also the timing of to Final Bronze Age). In contrast to this, pollen evidence from Broumovsko and České Švýcarsko to Final Bronze Age). In contrast to this, pollen evidence from Broumovsko and České Švýcarsko to Final Bronze Age). In contrast to this, pollen sandstone regions suggests more gradual acidifi - evidence from Broumovsko and České Švýcarsko sandstone regions suggests more gradual acidifi - evidence from Broumovsko and České Švýcarsko cation that took place between ca 4 700 and 3 000 sandstone regions suggests more gradual acidifi - cation that took place between ca 4 700 and 3 000 sandstone regions suggests more gradual acidifi - B.P. (Late Neolithic to Final Bronze Age according cation that took place between ca 4 700 and 3 000 B.P. (Late Neolithic to Final Bronze Age according cation that took place between ca 4 700 and 3 000 to archaeological chronology). This diff erence B.P. (Late Neolithic to Final Bronze Age according to archaeological chronology). This diff erence B.P. (Late Neolithic to Final Bronze Age according is probably due to the lack of prehistoric human to archaeological chronology). This diff erence is probably due to the lack of prehistoric human to archaeological chronology). This diff erence infl uence which was negligible in two later is probably due to the lack of prehistoric human infl uence which was negligible in two later is probably due to the lack of prehistoric human mentioned regions.

inﬂ uence which was negligible in two later mentioned regions.

infl uence which was negligible in two later According to arguments presented in this paper, soil acidifi cation and ecosystem depauperization According to arguments presented in this paper, soil acidifi cation and ecosystem depauperization According to arguments presented in this paper, is a process that is natural under climatic condi- soil acidifi cation and ecosystem depauperization is a process that is natural under climatic condi- soil acidifi cation and ecosystem depauperization tions of Central Europe. Sandstone substrata is a process that is natural under climatic conditions of Central Europe. Sandstone substrata is a process that is natural under climatic condi- are especially sensitive to loss of basic nutrients.

tions of Central Europe. Sandstone substrata are especially sensitive to loss of basic nutrients.

tions of Central Europe. Sandstone substrata Around 3 000 B.P., natural process of acidiﬁ cation are especially sensitive to loss of basic nutrients.

Around 3 000 B.P., natural process of acidiﬁ cation are especially sensitive to loss of basic nutrients.

culminated in both sandstone regions under Around 3 000 B.P., natural process of acidifi cation culminated in both sandstone regions under Around 3 000 B.P., natural process of acidifi cation study. This happened obviously without infl uence culminated in both sandstone regions under study. This happened obviously without infl uence culminated in both sandstone regions under of man. Nevertheless, human impact may have study. This happened obviously without infl uence of man. Nevertheless, human impact may have study. This happened obviously without infl uence been an important factor that speeded up this of man. Nevertheless, human impact may have been an important factor that speeded up this of man. Nevertheless, human impact may have process. This happened during Late and Final been an important factor that speeded up this process. This happened during Late and Final been an important factor that speeded up this

Fig. 4: Simpliﬁ ed percentage pollen diagram from the Tišice site. The moment of acidiﬁ cation is indicated on the right side.

Fig. 5: Ca²⁺ and Mg²⁺ total concentrations diagram from Anenské the údolí site. The period of acidiﬁ cation (de- rived from pollen diagram; Fig. 2) is indicated on the right side.

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112 Ferrantia • 44 / 2005

P. Pokorný & P. Kuneš Holocene acidiﬁ cation process recorded in pollen proﬁ les, Czech Republic Bronze Age (i.e. at about 3 000 B.P. again) in case

of Polomené hory sandstone area and in nearby- situated terraces of Middle Labe River. Woodland clearance, grazing and subsequent soil erosion were probably most important control mechanisms that played a role.

Acknowledgements

This study was supported by Ministry of the Environment of the Czech Republic, project no.

VaV 620/7/03. The authors owe a great deal to the organizers of II. Sandstone symposium at Vianden for partial sponsorship of the presentation of this paper.

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En République Tchèque, les paysages de grès repré- sentent un phénomène important. En dépit de ce fait, on ne sait que peu de choses au sujet de quelques aspects importants de leur histoire environnementale.

Les régions gréseuses České Švýcarsko et Broumovsko ont été récemment soumises à des analyses polliniques qui ont apporté des informations signiﬁ catives sur le développement de leur végétation au cours de l’holocène. De ce point de vue, l’histoire de ces paysages de grès se révèle étonnamment dramatique.

D’une part documentées par des recherches paléo- malacologiques, leurs conditions nutritives dans le passé pourraient avoir été sensiblement diﬀ érentes de celles que nous connaissons aujourd’hui. De nouveaux résultats palynologiques de České Švýcarsko conﬁ rment ce� e trouvaille. Dans l’holocène moyen, les forêts mixtes de chêne à grande abondance de noise� ier, de tilleul et d’orme formaient l’essentiel des espaces boisés. Plus tard, des substrats riches en éléments nutritifs ont été soumis à un appauvrissement provoqué très proba- blement par des changements climatiques. L’expansion du hêtre et du sapin argenté en fut le résultat. Le rôle de l’impact humain dans ce processus fut négligeable.

L’inﬂ uence humaine s’accélère seulement à partir de la période moderne.

D’autre part, l’existence dans le passé d’une végétation contrastante à échelle spatiale très réduite a été également largement soutenue par les analyses polliniques. Les données de la région de Broumovsko démontrent l’expansion et l’établissement de forêts d’épicéas dans des stations à inversion climatique. En revanche, on trouvait des chênaies mélangées au noise� ier quelques centaines de mètres au-dessus dans des stations plus lumineuses et plus chaudes. L’hypothèse de stations rélictuelles de grandes pinèdes dans tous les paysages de grès a été également rejetée du au très faible contenu de pollen de pin. En conclusion le transport de pollen et le processus de sédimentation dans des proﬁ ls de tourbe ont apparemment eu lieu à échelle locale. C’est pourquoi on peut y retracer surtout l’historique de la végétation des alentours immédiats, moins celui de l’espace régional ou global.

Les résultats font ressortir clairement que les régions de grès diff èrent signifi cativement dans leur histoire environnementale. Les diff érences climatiques et géolo- giques ainsi que les historiques de migration distinctes en sont la cause.

Histoire de la végétation des paysages de grès tchèques dérivée du proﬁ l de tourbières Mots-clés: paléoécologie; palynologie; analyse de pollen; développement de la végétation;

changement environnemental; holocène; acidiﬁ cation Résumé de la présentation

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114 Ferrantia • 44 / 2005