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Francesc Gallart - One of the best experts on this subject based on the ideXlab platform.
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The Origin of Badlands
Badlands Dynamics in a Context of Global Change, 2018Co-Authors: Mariano Moreno-de Las Heras, Francesc GallartAbstract:Abstract Badlands are erosive landforms of highly dissected morphology that are pervasive on soft bedrock in a variety of climate conditions. Although these systems share common geomorphological features, Badlands may show diverse erosive activity, age and dynamic behaviour, which complicates the analysis of the reasons for badland initiation. This study's extensive review of badland mechanisms and predisposing factors indicates that badland development is controlled by the incidence of four general terrain instability factors: relief vigour in the form of topographic gradient or active base-level conditions, weatherable and erosion-susceptible soft lithology, an erosive climate and, finally, a disturbance or environmental condition limiting the development of protective vegetation. Local lithology, regional to local tectonics, climate oscillations and the effects of both extreme natural events and human action play a dominant role in determining whether these four instability factors converge in a landscape, ultimately to lead to the initiation, stabilization and rejuvenation of Badlands.
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Lithology controls the regional distribution and morphological diversity of montane Mediterranean Badlands in the upper Llobregat basin (eastern Pyrenees)
Geomorphology, 2016Co-Authors: Mariano Moreno-de Las Heras, Francesc GallartAbstract:Abstract Badlands are pervasive in a wide range of environmental conditions across the Mediterranean region, including arid, semiarid, and humid environments. On montane (cold subhumid and humid) Mediterranean landscapes, harsh thermal conditions on north-facing hillslopes favour intense bedrock weathering by freezing and impose serious constraints on plant colonization. The above are the customary arguments to explain the high abundance of montane Badlands on north-exposed shady aspects. We studied the distribution and morphological diversity of Badlands in the upper Llobregat basin (Catalan Pyrenees, NE Spain), using remote sensing information (high-resolution orthophotos and complementary Landsat 8 imagery), digital elevation data, and regional information on lithology. Badlands extend over about 200 ha in the upper Llobregat basin and occur on two different parent materials, swelling (smectite-rich) continental Garumnian lutites of late Cretaceous age, and nonswelling (illitic) marine Eocene marls. Vegetation, assessed by remote-sensed vegetation greenness, is less developed on north-facing badland slopes. However, badland slope-aspect distribution varies considerably with lithology. While Badlands on Eocene marls show preferential distribution on north-facing shady slopes, badland occurrence on Garumnian lutites does not reveal clear slope-aspect anisotropy patterns. Lithology also affects slope gradient, with Badlands on Eocene marls showing rougher topography (30–40° average slope angle) than on Garumnian lutites (20–30°). Badland morphological differences induced by lithology are discussed in terms of the greater weathering susceptibility and slope instability of the swelling, smectite-rich Garumnian lutites than of the nonswelling Eocene marls. Elevation, which broadly controls annual precipitation and winter air temperature within the region, shows no clear influence on badland distribution. Overall, our results reveal lithology as the main factor controlling badland distribution and morphological diversity under the montane Mediterranean conditions of the upper Llobregat basin.
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Thirty years of studies on Badlands, from physical to vegetational approaches. A succinct review
CATENA, 2013Co-Authors: Francesc Gallart, Michela Marignani, Elisa Santi, Nuria Pérez-gallego, Simona MaccheriniAbstract:The scientific subjects addressed in the research into Badlands since the publication of Bryan and Yair's book (Bryan, R.B. and Yair, A. (Editors), 1982 Badland geomorphology and piping. Geo Books, Norwich, 408 pp.) are briefly analysed. With a steadily increasing number of papers per year, attention to some aspects, such as runoff generation, piping and the role of lithology and soils, varied, whereas the percentage of studies on erosion rates increased steadily over time. Vegetation was not a subject of research in early papers, as most of the papers dealing with vegetation were rather descriptive and published in local or limited-diffusion media, which contrasts with the present situation when about 40% of papers published in international journals about Badlands address some aspect of vegetation. However, the growth in the attention paid to vegetation and erosion rates was not linked to any increase in papers dealing with badland reclamation. Badlands are now seen as a group of systems with some common features but diverse dynamics, depending mainly on climatic and lithological drivers. More attention should be paid in the future to investigating the evolution of these landforms over time, mostly through modelling studies, whereas emerging technologies foster detailed analyses that were not possible formerly. Although some badland areas determine on- and off-site environmental issues, others are spots of landscape diversity that merit protection rather than reclamation.
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Short- and long-term studies of sediment dynamics in a small humid mountain Mediterranean basin with Badlands
Geomorphology, 2013Co-Authors: Francesc Gallart, Nuria Pérez-gallego, Jerome Latron, G. Catari, Núria Martínez-carreras, G. NordAbstract:Abstract Badland landscapes are the main sediment sources in the Vallcebre area (Eastern Pyrenees, Catalonia, Spain). Short-term studies (up to 3-years long) carried out between 1980 and 1994 were used to estimate the rates of both denudation on bare surfaces and sediment production at the plot scale, to analyse the seasonal dynamics of bedrock weathering and regolith behaviour, and to study the relationships between geomorphic activity and herbaceous plant colonisation. Since 1990, stream flow and suspended sediment loads have been monitored using three gauging stations equipped with infrared backscattering turbidimeters, ultra-sonic beam attenuation solids sensors and automatic water samplers. The combination of the two different approaches has been useful for a better perception of the dynamics of the badland systems and to assess the long-term contribution of these areas to the basin sediment loads. Badland erosion at the event scale for a period of 15 years was simulated with the KINEROS2 model and allowed the long-term comparison between badland erosion and sediment yield at the small basin scale. Badlands are the main source of sediment in the basin for most of the events, but infrequent runoff events cause the removal of sediment stores and the activation of other sediment sources. The analysis of the uncertainty of sediment yield measurements for a range of record durations demonstrated that long records are needed for obtaining acceptable results due to the high interannual variability. Relatively low-cost short-term geomorphic observations may provide information useful for assessing the long-term sediment production in these basins with badland areas only if the observations are used to implement a model able to simulate long-term observations.
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Simulating badland erosion with KINEROS2 in a small Mediterranean mountain basin (Vallcebre, Eastern Pyrenees)
CATENA, 2007Co-Authors: Núria Martínez-carreras, Montserrat Soler, E. Hernández, Francesc GallartAbstract:Abstract The Ca lʻIsard catchment (1.32 km 2 ), a sub-basin of the Vallcebre experimental catchments, yields large amounts of sediments (about 580 Mg km − 2 year − 1 ) that are produced in relatively small but very active eroded areas (Badlands). Several lines of evidence suggest that there is a delay between sediment production, caused by intense summer rainstorms, and sediment transport, occasioned by the main floods produced by large precipitation events following wet antecedent conditions. First, a calibration–validation exercise was carried out with sediment yield data obtained using containers provided with slot divisors in a Badlands micro-catchment (1240 m 2 ). Then, the model was applied to the main Badlands areas in the Ca lʻIsard sub-catchment for a 4-year period and the simulated sediment yields were compared with the records at the gauging station. The test was performed with the Generalized Likelihood Uncertainty Estimation (GLUE) approach for assessing the uncertainty associated with model predictions, which assumes that many parameter sets can give acceptable simulations. The results demonstrated the capacity of KINEROS2 to simulate badland erosion, although it showed limited robustness. A clear temporal mismatch between erosion and sediment transport and the relevance of sediment stores in the catchment were confirmed, while the total weights of sediment were generally under-predicted. The limited suitability of the area used for calibration or the role of sediment sources not simulated in the approach may account for this shortcoming.
Simona Maccherini - One of the best experts on this subject based on the ideXlab platform.
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Germinable Soil Seed Bank in Biancana Badlands
Diversity, 2019Co-Authors: Simona Maccherini, Elisa Santi, Dino TorriAbstract:Seed banks are important for understanding vegetation dynamics and habitat regeneration potential. Biancana Badlands are vanishing landscapes where recurring and non-recurring management has been advocated to restore vegetation. Here, we investigated germinable seed bank structure and composition of a biancana badland in central Italy and evaluated the relationship between the standing vegetation and soil seed bank. We identified four land cover classes in five biancana Badlands of Tuscany (central Italy) and collected data from 132 vegetation plots and 660 soil cores. We recorded 117 species in the standing vegetation. The seedlings that emerged from the soil samples, mostly annual species, numbered 183 and belonged to 31 taxa (392.5 seedlings/m−2 on average across the four land cover classes). Standing vegetation showed an aggregated spatial pattern with distinct communities while the seed bank showed a less aggregated spatial pattern. The similarity between the seed bank and standing vegetation was low. In contrast with the features generally found for disturbed and pioneer communities, but in line with seed bank characteristics of other Badlands, the seed bank was particularly poor in species.
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Badlands and the Dynamics of Human History, Land Use, and Vegetation Through Centuries
Badlands Dynamics in a Context of Global Change, 2018Co-Authors: Dino Torri, Michela Marignani, Elisa Santi, Mauro Rossi, Francesco Brogi, Giovanni Bacaro, Enrico Tordoni, Valerio Amici, Simona MaccheriniAbstract:Abstract In temperate climates, vegetation dynamics can dominate the fate of the Badlands. In fact, in absence of disturbances such a grazing and burning, plant encroachment can condemn Badlands to disappear. Thus, this type of Badlands is either formed and developed under more arid conditions or due to some sort of mismanagement and misuse. This study provides an update on the denudation rate on this type of Badlands (for a biancana badland in Central Italy, close to the ancient town of Siena). The result shows a denudation rate of 2 cm a−1. Hence, the biancana site resulted to have been formed starting from the XIV century. The climatic conditions were similar to the present one, even if cooler and wetter. Hence, plants could have easily colonized the erosion scars indicating that factors controlling the badland origin should be searched elsewhere. Anthropic action was explored with a deep insight into the medieval period. It resulted that (1) the plague depopulation (which kept peasant population very low for more than 50 years), (2) the change of the social structure in charge of the countryside management and (3) the need for the Siena republic to attract peasants concurred to the creations of favourable circumstances for the Badlands formation from previous pastures and croplands. Similar factors can hold for many Badlands, following local history.
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Thirty years of studies on Badlands, from physical to vegetational approaches. A succinct review
CATENA, 2013Co-Authors: Francesc Gallart, Michela Marignani, Elisa Santi, Nuria Pérez-gallego, Simona MaccheriniAbstract:The scientific subjects addressed in the research into Badlands since the publication of Bryan and Yair's book (Bryan, R.B. and Yair, A. (Editors), 1982 Badland geomorphology and piping. Geo Books, Norwich, 408 pp.) are briefly analysed. With a steadily increasing number of papers per year, attention to some aspects, such as runoff generation, piping and the role of lithology and soils, varied, whereas the percentage of studies on erosion rates increased steadily over time. Vegetation was not a subject of research in early papers, as most of the papers dealing with vegetation were rather descriptive and published in local or limited-diffusion media, which contrasts with the present situation when about 40% of papers published in international journals about Badlands address some aspect of vegetation. However, the growth in the attention paid to vegetation and erosion rates was not linked to any increase in papers dealing with badland reclamation. Badlands are now seen as a group of systems with some common features but diverse dynamics, depending mainly on climatic and lithological drivers. More attention should be paid in the future to investigating the evolution of these landforms over time, mostly through modelling studies, whereas emerging technologies foster detailed analyses that were not possible formerly. Although some badland areas determine on- and off-site environmental issues, others are spots of landscape diversity that merit protection rather than reclamation.
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The recurring cycles of biancana Badlands: Erosion, vegetation and human impact
CATENA, 2013Co-Authors: D Torri, Michela Marignani, Elisa Santi, Mauro Rossi, Lorenzo Borselli, Simona MaccheriniAbstract:Abstract The biancana Badlands, a typical element of the southern Tuscany landscape, were in expansion for centuries, until bulldozers began erasing them for land reclamation purposes. Over the last 10–15 years some of the scattered remnants of biancanas have been placed under protection in order to preserve their biodiversity and their particular cultural and geomorphological landscapes. Rural abandonment and the lack of appropriate management practices have contributed to vegetation encroaching on biancana badland slopes, causing a loss of elements of high ecological and cultural values, as well as eroded spots. The aim of this paper is to explore the direction and rate of change in land use of the biancana badland landscapes over the last 50 years, evaluating the erosion–vegetation dynamics and examining the processes involved in two biancana Badlands, “Lucciola Bella” and “Crete di Camposodo & Crete di Leonina”, which are Sites of Community Importance. First, we analysed the landscape changes that occurred in the biancana areas from 1954 to 2005, comparing old and recent land use maps. TWINSPAN classification was applied on selected plots of a plant dataset to distinguish vegetation types and identify the indicator species of each different type. We then evaluated soil erodibility on the eroded biancana surfaces, regosols and well-developed vertisols, which represent the coexisting extremes of the soil situation within the biancana Badlands. We empirically assessed the effects of a few roots on saturated soil shear strength to introduce direct links between plants and soil processes. Our results showed a decrease in bare or scarcely vegetated spots of 0.9 ha y − 1 : if the encroachment continues to progress at this rate, in 35–40 years from now all the biancana domes will be completely re-vegetated. Encroachment on the most eroded biancanas was mainly ascribed to generalist ruderal species, such as Avena fatua and Dactylis glomerata . We showed that rills and subsurface micropipes are characterized by the same erosion processes, meaning that they can be contrasted and eventually halted by the same means, and we observed a clear positive trend that will substantially suppress rilling at very low plant cover (no more than 20%). Badlands were previously kept alive by limited but nonetheless devastating grazing activities. If this picture is correct, then mimicking traditional badland grazing practices seems to be a necessary step towards saving the landscape and biodiversity that the protected areas were established to preserve.
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determinants of plant community composition of remnant biancane Badlands a hierarchical approach to quantify species environment relationships
Applied Vegetation Science, 2011Co-Authors: Simona Maccherini, Michela Marignani, Margherita Gioria, Monia Renzi, Duccio Rocchini, Elisa Santi, D Torri, J Tundo, Olivier HonnayAbstract:Question: Which environmental variables best explain patterns in the vegetation of biancane Badlands? What is the role of spatial scales in structuring the vegetation of biancane Badlands within the agricultural matrix? Location: Five biancane Badlands in Central Italy (Tuscany). Methods: An object-oriented approach on high-resolution multispectral images was used to classify physiognomic vegetation types in five biancane Badlands. Within each badland, data on vascular plant species abundance were collected using a stratified random design. Variation partitioning based on partial redundancy analysis was used to evaluate the contribution of three sets of environmental predictors, recorded at the spatial scales of plot, patch and biancane badland in explaining patterns in plant community composition. Results: Environmental variables included in the final model ‐ electrical conductivity and carbon/nitrogen ratio (plot scale), shape index (patch scale) and area (biancane badland scale) ‐ accounted for 15.5% of the total variation in plant community composition. Soil characteristics measured at the plot level explained the majority of variation. In the smallest Badlands, Bromus erectus perennial grasslands were absent, while annual grasslands, linked with harsh soil conditions (i.e. high soil salinity), were not affected by either the surface area of biancane Badlands or by the soil nitrogen availability. Conclusions: The identification of the major predictors of patterns in remnant vegetation requires conducting investigations at multiple spatial scale. Management strategies should operate at different spatial scale, preventing any further reduction in the size of existing Badlands and relying on habitat- instead of area-focused conservation practices.
Dino Torri - One of the best experts on this subject based on the ideXlab platform.
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Germinable Soil Seed Bank in Biancana Badlands
Diversity, 2019Co-Authors: Simona Maccherini, Elisa Santi, Dino TorriAbstract:Seed banks are important for understanding vegetation dynamics and habitat regeneration potential. Biancana Badlands are vanishing landscapes where recurring and non-recurring management has been advocated to restore vegetation. Here, we investigated germinable seed bank structure and composition of a biancana badland in central Italy and evaluated the relationship between the standing vegetation and soil seed bank. We identified four land cover classes in five biancana Badlands of Tuscany (central Italy) and collected data from 132 vegetation plots and 660 soil cores. We recorded 117 species in the standing vegetation. The seedlings that emerged from the soil samples, mostly annual species, numbered 183 and belonged to 31 taxa (392.5 seedlings/m−2 on average across the four land cover classes). Standing vegetation showed an aggregated spatial pattern with distinct communities while the seed bank showed a less aggregated spatial pattern. The similarity between the seed bank and standing vegetation was low. In contrast with the features generally found for disturbed and pioneer communities, but in line with seed bank characteristics of other Badlands, the seed bank was particularly poor in species.
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Badlands and the Dynamics of Human History, Land Use, and Vegetation Through Centuries
Badlands Dynamics in a Context of Global Change, 2018Co-Authors: Dino Torri, Michela Marignani, Elisa Santi, Mauro Rossi, Francesco Brogi, Giovanni Bacaro, Enrico Tordoni, Valerio Amici, Simona MaccheriniAbstract:Abstract In temperate climates, vegetation dynamics can dominate the fate of the Badlands. In fact, in absence of disturbances such a grazing and burning, plant encroachment can condemn Badlands to disappear. Thus, this type of Badlands is either formed and developed under more arid conditions or due to some sort of mismanagement and misuse. This study provides an update on the denudation rate on this type of Badlands (for a biancana badland in Central Italy, close to the ancient town of Siena). The result shows a denudation rate of 2 cm a−1. Hence, the biancana site resulted to have been formed starting from the XIV century. The climatic conditions were similar to the present one, even if cooler and wetter. Hence, plants could have easily colonized the erosion scars indicating that factors controlling the badland origin should be searched elsewhere. Anthropic action was explored with a deep insight into the medieval period. It resulted that (1) the plague depopulation (which kept peasant population very low for more than 50 years), (2) the change of the social structure in charge of the countryside management and (3) the need for the Siena republic to attract peasants concurred to the creations of favourable circumstances for the Badlands formation from previous pastures and croplands. Similar factors can hold for many Badlands, following local history.
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Preliminary study of the erosion mechanisms in a biancana badland (Tuscany, Italy)
CATENA, 1994Co-Authors: Dino Torri, Antonella Colica, David RockwellAbstract:Abstract Italian Badlands are present along the Appennini mountains, with an annual precipitation which ranges from 400 to 1200 mm. The genesis of these Badlands has often been studied, whereas current processes and erosion rates have only rarely been examined and measured. This paper describes a preliminary study on a badland developed in temperate mediterranean climate and located in SW Tuscany (Italy). The selected site is characterized by biancane, dome-shaped features a few meters in height, generally having a vegetated NNE aspect and severely eroded SSW slope, with a sub-horizontal basal pediment. Field rainfall and runoff experiments were carried out. Field results were substantiated by data collected in specially devised laboratory tests. It was concluded that near-surface pipes — which develop at the point of contact between a surficial layer of weathered and severely fractured regolith and the less fractured and weathered regolith underneath — are the main drainage channels, while rills play a secondary role. Soil detachment is largely due to mechanical and chemical slaking of the regolith during infiltration. The role of runoff is almost solely transport. In particular, it was found that the runoff detachment rate is limited by the rate at which the water front penetrates into the regolith.
Elisa Santi - One of the best experts on this subject based on the ideXlab platform.
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Germinable Soil Seed Bank in Biancana Badlands
Diversity, 2019Co-Authors: Simona Maccherini, Elisa Santi, Dino TorriAbstract:Seed banks are important for understanding vegetation dynamics and habitat regeneration potential. Biancana Badlands are vanishing landscapes where recurring and non-recurring management has been advocated to restore vegetation. Here, we investigated germinable seed bank structure and composition of a biancana badland in central Italy and evaluated the relationship between the standing vegetation and soil seed bank. We identified four land cover classes in five biancana Badlands of Tuscany (central Italy) and collected data from 132 vegetation plots and 660 soil cores. We recorded 117 species in the standing vegetation. The seedlings that emerged from the soil samples, mostly annual species, numbered 183 and belonged to 31 taxa (392.5 seedlings/m−2 on average across the four land cover classes). Standing vegetation showed an aggregated spatial pattern with distinct communities while the seed bank showed a less aggregated spatial pattern. The similarity between the seed bank and standing vegetation was low. In contrast with the features generally found for disturbed and pioneer communities, but in line with seed bank characteristics of other Badlands, the seed bank was particularly poor in species.
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Badlands and the Dynamics of Human History, Land Use, and Vegetation Through Centuries
Badlands Dynamics in a Context of Global Change, 2018Co-Authors: Dino Torri, Michela Marignani, Elisa Santi, Mauro Rossi, Francesco Brogi, Giovanni Bacaro, Enrico Tordoni, Valerio Amici, Simona MaccheriniAbstract:Abstract In temperate climates, vegetation dynamics can dominate the fate of the Badlands. In fact, in absence of disturbances such a grazing and burning, plant encroachment can condemn Badlands to disappear. Thus, this type of Badlands is either formed and developed under more arid conditions or due to some sort of mismanagement and misuse. This study provides an update on the denudation rate on this type of Badlands (for a biancana badland in Central Italy, close to the ancient town of Siena). The result shows a denudation rate of 2 cm a−1. Hence, the biancana site resulted to have been formed starting from the XIV century. The climatic conditions were similar to the present one, even if cooler and wetter. Hence, plants could have easily colonized the erosion scars indicating that factors controlling the badland origin should be searched elsewhere. Anthropic action was explored with a deep insight into the medieval period. It resulted that (1) the plague depopulation (which kept peasant population very low for more than 50 years), (2) the change of the social structure in charge of the countryside management and (3) the need for the Siena republic to attract peasants concurred to the creations of favourable circumstances for the Badlands formation from previous pastures and croplands. Similar factors can hold for many Badlands, following local history.
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Thirty years of studies on Badlands, from physical to vegetational approaches. A succinct review
CATENA, 2013Co-Authors: Francesc Gallart, Michela Marignani, Elisa Santi, Nuria Pérez-gallego, Simona MaccheriniAbstract:The scientific subjects addressed in the research into Badlands since the publication of Bryan and Yair's book (Bryan, R.B. and Yair, A. (Editors), 1982 Badland geomorphology and piping. Geo Books, Norwich, 408 pp.) are briefly analysed. With a steadily increasing number of papers per year, attention to some aspects, such as runoff generation, piping and the role of lithology and soils, varied, whereas the percentage of studies on erosion rates increased steadily over time. Vegetation was not a subject of research in early papers, as most of the papers dealing with vegetation were rather descriptive and published in local or limited-diffusion media, which contrasts with the present situation when about 40% of papers published in international journals about Badlands address some aspect of vegetation. However, the growth in the attention paid to vegetation and erosion rates was not linked to any increase in papers dealing with badland reclamation. Badlands are now seen as a group of systems with some common features but diverse dynamics, depending mainly on climatic and lithological drivers. More attention should be paid in the future to investigating the evolution of these landforms over time, mostly through modelling studies, whereas emerging technologies foster detailed analyses that were not possible formerly. Although some badland areas determine on- and off-site environmental issues, others are spots of landscape diversity that merit protection rather than reclamation.
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The recurring cycles of biancana Badlands: Erosion, vegetation and human impact
CATENA, 2013Co-Authors: D Torri, Michela Marignani, Elisa Santi, Mauro Rossi, Lorenzo Borselli, Simona MaccheriniAbstract:Abstract The biancana Badlands, a typical element of the southern Tuscany landscape, were in expansion for centuries, until bulldozers began erasing them for land reclamation purposes. Over the last 10–15 years some of the scattered remnants of biancanas have been placed under protection in order to preserve their biodiversity and their particular cultural and geomorphological landscapes. Rural abandonment and the lack of appropriate management practices have contributed to vegetation encroaching on biancana badland slopes, causing a loss of elements of high ecological and cultural values, as well as eroded spots. The aim of this paper is to explore the direction and rate of change in land use of the biancana badland landscapes over the last 50 years, evaluating the erosion–vegetation dynamics and examining the processes involved in two biancana Badlands, “Lucciola Bella” and “Crete di Camposodo & Crete di Leonina”, which are Sites of Community Importance. First, we analysed the landscape changes that occurred in the biancana areas from 1954 to 2005, comparing old and recent land use maps. TWINSPAN classification was applied on selected plots of a plant dataset to distinguish vegetation types and identify the indicator species of each different type. We then evaluated soil erodibility on the eroded biancana surfaces, regosols and well-developed vertisols, which represent the coexisting extremes of the soil situation within the biancana Badlands. We empirically assessed the effects of a few roots on saturated soil shear strength to introduce direct links between plants and soil processes. Our results showed a decrease in bare or scarcely vegetated spots of 0.9 ha y − 1 : if the encroachment continues to progress at this rate, in 35–40 years from now all the biancana domes will be completely re-vegetated. Encroachment on the most eroded biancanas was mainly ascribed to generalist ruderal species, such as Avena fatua and Dactylis glomerata . We showed that rills and subsurface micropipes are characterized by the same erosion processes, meaning that they can be contrasted and eventually halted by the same means, and we observed a clear positive trend that will substantially suppress rilling at very low plant cover (no more than 20%). Badlands were previously kept alive by limited but nonetheless devastating grazing activities. If this picture is correct, then mimicking traditional badland grazing practices seems to be a necessary step towards saving the landscape and biodiversity that the protected areas were established to preserve.
-
determinants of plant community composition of remnant biancane Badlands a hierarchical approach to quantify species environment relationships
Applied Vegetation Science, 2011Co-Authors: Simona Maccherini, Michela Marignani, Margherita Gioria, Monia Renzi, Duccio Rocchini, Elisa Santi, D Torri, J Tundo, Olivier HonnayAbstract:Question: Which environmental variables best explain patterns in the vegetation of biancane Badlands? What is the role of spatial scales in structuring the vegetation of biancane Badlands within the agricultural matrix? Location: Five biancane Badlands in Central Italy (Tuscany). Methods: An object-oriented approach on high-resolution multispectral images was used to classify physiognomic vegetation types in five biancane Badlands. Within each badland, data on vascular plant species abundance were collected using a stratified random design. Variation partitioning based on partial redundancy analysis was used to evaluate the contribution of three sets of environmental predictors, recorded at the spatial scales of plot, patch and biancane badland in explaining patterns in plant community composition. Results: Environmental variables included in the final model ‐ electrical conductivity and carbon/nitrogen ratio (plot scale), shape index (patch scale) and area (biancane badland scale) ‐ accounted for 15.5% of the total variation in plant community composition. Soil characteristics measured at the plot level explained the majority of variation. In the smallest Badlands, Bromus erectus perennial grasslands were absent, while annual grasslands, linked with harsh soil conditions (i.e. high soil salinity), were not affected by either the surface area of biancane Badlands or by the soil nitrogen availability. Conclusions: The identification of the major predictors of patterns in remnant vegetation requires conducting investigations at multiple spatial scale. Management strategies should operate at different spatial scale, preventing any further reduction in the size of existing Badlands and relying on habitat- instead of area-focused conservation practices.
Roser Guàrdia - One of the best experts on this subject based on the ideXlab platform.
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Soil seed bank and seedling dynamics in Badlands of the Upper Llobregat basin (Pyrenees)
CATENA, 2000Co-Authors: Roser Guàrdia, Francesc Gallart, Josep M. NinotAbstract:Abstract In the Badlands of the Upper Llobregat basin, vegetation is sparse and heterogeneous. The harsh conditions generated with the formation of the Badlands involve a regressive succession. On the upper part of the slope, a sharp change can be seen between dense communities and denuded badland slopes. Nevertheless, recolonization of the Badlands rarely occurs. Scarce seed availability or low capacity of seeds to germinate in such unfavorable conditions may be the main causes. The soil seed bank was sampled in two micro-catchments; a total of 105 soil cores were extracted along three parallel transects. Soil samples were washed through a set of sieves, and seeds were separated and identified. Seedling emergence and mortality were also recorded monthly from April 1990 to December 1991, on two permanent plots in a nearby micro-catchment. An unexpected soil seed bank was found. A relatively high species number has been found with rather small and slightly heterometric seeds. Strong relation between seed bank composition and established vegetation has been detected. Seedling emergence occurred mainly from May to August. The species composition was also dominated by the most frequent species in the Badlands and in the soil seed bank. Seedling mortality does not appear to be directly associated with the erosive processes, as it occurred throughout the year. It seems that seedling survival rates could be sufficient to ensure persistence of the current vegetation in badland areas. We conclude that there is no single reason that can explain the low vegetation cover in Badlands but rather there is a combination of several restrictive factors. Lack of seed availability within the reduced favorable period for germination and low seedling establishment contribute in part to this low colonization.
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Geomorphic agents versus vegetation spreading as causes of badland occurrence in a Mediterranean subhumid mountainous area.
CATENA, 2000Co-Authors: David Regüés, Roser Guàrdia, Francesc GallartAbstract:Abstract Previous evidence on the chief role of physical weathering on badland development in the Vallcebre area (South Eastern Pyrenees) led to the study of the amounts of energy available for the main geomorphic agents, and to analyze the results in the light of the patterns of vegetation cover and species distribution, in order to explain both the occurrence of these badland forms and their preference for north-facing (shady) hillslopes. Results showed that the weathering potential provided by freezing is about two orders of magnitude greater than rainfall kinetic energy, and that the former strongly depends on hillslope aspect. The study of vegetation demonstrated that vegetation is poorer in cover and species composition on shady hillslopes than on sunny ones, spontaneous revegetation of these surfaces being restrained by cold thermal conditions rather than by water availability. These results show that the occurrence of these badland areas depends on montane climatic attributes that control geomorphic and biological processes, and that are different from those that promote the occurrence of Badlands in dry Mediterranean areas. The preference for northern aspects provides evidence for these differences.
