Dissertations / Theses on the topic 'Anthropogenic soil'

Master of Science
Department of Agronomy
Ganga M. Hettiarachchi
Human activities have the potential to alter soil biochemical properties in a number of different ways. This thesis will focus on how agricultural practices (tillage and cropping system), climate change, and urban soil pollution (primarily lead and arsenic) affect soil biochemical properties. Two incubation studies were conducted to determine how human activities influence soil biochemical properties. The first study focused on how altered temperature and moisture regimes affected soil properties from four different agroecosystems. Four different soils were incubated under two different soil preparation methods (sieved <4mm and <0.25 mm), three different temperature treatments (12, 24, and 36°C), and two different moisture treatments (field capacity and 80% of field capacity) for 180 days. Destructive samples were taken at 7, 30, 60, 120, and 180 days and the soil microbial community was analyzed using phospholipid fatty acid analysis (PLFA). The second study investigated how soil amendment treatments (Mushroom Compost and Composted Biosolids) of an industrially contaminated site affected the biochemical properties of that soil. Surface soil samples collected 435 days after compost addition from urban garden test plots located adjacent to a former rail yard in Monon, Indiana. Soils were incubated for 30 days to stimulate microbial activity. Following incubation, the soil was analyzed for PLFA, soil enzymes, and available metal fractions. In the first study the greatest differences were found between the <4mm and the <0.25 mm size fractions – which highlights the effect of soil aggregation and structure on microbial populations. After aggregation effects, temperature treatment had the next largest effect on microbial populations, with the greatest biomass in the middle (24°C) treatment. The second study assessed different soil amendments on soil microbial properties and metal availability. Composted biosolids reduced metal availability and increased microbial enzyme activity and biomass.

The aim of this work is to determine the changes created by a covering anthropogenic in an area in the south of Bremerhaven, the port of Bremen, Germany. In 1973 it was started the construction of a highway connecting commercial purposes which required, however, the excavation of soil material that then had to be repositioned. The study area sees a field previously used for farming purposes, as a place designated to overlap: the Ahnthammsmoor lost its function and was upset in all the surface. The filler material necessarily involves physical changes (high, degree of compaction and level of ground water), chemical (addition of new organic material), ecosystemic (for the disruption of flora and fauna) and economic (loss of existing functionality ). The problem was then faced with environmental and soil investigation, going to recreate the scenario above the motorway construction and characterize the new 'artificial environment'.

In an interdisciplinary study requiring the synergistic association of historical evidence and chemical and biochemical analyses, this thesis investigates the properties and characteristics of historically modified soils known as anthrosols. These soils, developed through the anthropogenic addition of high volumes of organic-rich municipal waste materials to land, including human and animal waste, as part of the waste management practices in medieval urban communities in Scotland at St Andrews, Roxburgh and Elgin, offer an insight to the state and dynamics of these organic material. Soil is one of the most sensitive environmental domains to transformation. These transformations are visible from the alterations to the physical and chemical properties of soil. Anthropogenic activities may leave behind signatures in the soil in the form of artefacts, ecofacts, elemental enrichment or depletion, enhancement in soil magnetic properties and organic matter content. In the historical dimension of this study, the observable features and measurable properties of soil profiles are exploited to reveal past organisation and functions of cultural landscapes by carefully studying the stratigraphic units of soil profile, and examining the association of each unit with settlement artefacts and soil properties. Through comparison with historical records of past events on the respective study sites, the relationship between the soils record of past human activities is observed through physical, chemical and biochemical properties. The historical record is used to assess if such evidence can be used reliably to develop the account of site use for the medieval burghs of Scotland. In the environmental aspect, investigation focuses on the physical and chemical conditions of these soils in terms of their carbon content, composition, residence time estimates and their role in global C cycle and terrestrial carbon budgeting. Past investigations of anthopogenically-deepened soils have been interpreted with respect to historical site use, however, the environmental implications of the resultant accumulated organic material or residue have not previously been considered in much detail. A particular novelty of this aspect of the project is that it is an in-depth examination of anthropogenic soils with known histories extending into the medieval period. This time-depth allows a new understanding of the processes and products of decomposition of known organic materials that were added to soil. The biophysicochemical data obtained from these soils such as their extant organic carbon content and variability with depth, the composition of the various carbon species that together constitute soil organic matter, and biological community and activity (microorganisms and enzymes) provides critical information on the relative recalcitrance, state of decomposition, and the mechanism of stabilisation of these materials in the soil.

The formation of two sediment types in Orkney is elucidated. Both are demonstrated to be the result of anthropogenic sedimentary processes, deep top soils the result of arable activity, farm mounds the result of habitation activity. Deep top soils commenced formation c 1200 AD either as a spontaneous innovation due to increasing population pressure or as a new agricultural technique introduced with monastic settlement. Cessation of deep top soil formation is attributed to the 1800s agricultural improvements when new forms of land fertilizer were introduced. The land use associated with deep top soil formation was the tunmal, the most intensively cultivated part of the early township. The materials used to sustain this intensive cultivation resulted in deep top soil formation. These materials were dominantly turf from the hill land and grazing land together with variable quantities of animal manure and a little seaweed. Deep top soils are located in West Mainland on naturally less fertile soils, where seaweed was in short supply and where population density was relatively high. Farm mound formation commenced over a thousand year period, between the Iron Age and late Norse period. The major impetus to farm mound formation was the Norse settlement commencing c 800 AD. Two farm mounds examined in detail indicate a mound core was deposited using primarily a turf and manure mixture. At one site this alleviated a flooding hazard. The core was then covered with turves and peat, creating a living surface upon which pathways and fertilized garden plots are evident. In the latter stages of farm mound formation their use was as a midden where toft wastes, dominantly ash, were deposited. Farm mounds are restrictedin their distribution to Sanday and North Ronaldsay where early population levels were greatest and where ample seaweed was available for land fertilization instead of toft wastes.

Deep anthropogenic topsoils – those augmented through long-term additions of mineral bulk among fertilising agents – retain in both their physical and chemical make-up significant indicators for cultural activity. This project researched the geographical distribution and historical context of deep anthropogenic topsoils in Scotland and the Isles, and used this information to investigate the impact of current land cover upon the cultural information they retain. In so doing, the project investigated the potential for conservation of this significant cultural resource. A review of the historical information available on agricultural and manuring practices for Scotland identified several factors likely to affect deep topsoil distribution and frequency. These were: the availability of bulk manures to Scottish farmers, the significance of the seaweed resource in determining fertiliser strategies in coastal areas, and the influence of urban settlement and associated patterns of domestic and industrial waste disposal on the location of deep topsoils. Evidence for widespread deep topsoil development was limited. The primary data source used – the First Statistical Account of Scotland – was manipulated into a spatial database in ArcView GIS, to which geographical data from the Soil Survey of Scotland and national archaeological survey databases were added. This was used to devise a survey programme aiming both to investigate the potential factors affecting soil development listed above, and to locate deep topsoil sites for analysis. Three sites were identified with deep topsoils under different cover types (woodland, arable and pasture). The urban-influenced context of two of these highlighted the significance of urban settlement to the location of Scottish deep topsoils. Analysis of pH, organic matter, and total phosphorus content showed a correlation between raised organic matter and a corresponding increase in phosphorus content in soils under permanent vegetation. By contrast, soils under arable cultivation showed no such rise. This was attributed to the action of cropping in removing modern organic inputs prior to down-profile cycling. The potential for pasture and woodland cover to affect relict soil signatures was therefore observed. Thin section analysis aimed to both provide micromorphological characterisation of the three deep topsoil sites and investigate the effect of modern land cover on micromorphological indicators. Distinctive differences in micromorphological character were observed between the rural and urban deep topsoils, with the latter showing a strong focus on carbonised fuel residues and industrial wastes. All sites showed a highly individual micromorphological character, reflective of localised fertilising systems. There was no correlation between land cover type and survival of material indictors for anthropogenic activity, with soil cultural indicators surviving well, particularly those characteristic of urban-influenced topsoils. Suggestions for preservation strategies for this potentially rare and highly localised cultural resource included the incorporation of deep anthropogenic topsoil conservation into current government policy relating to care of the rural historic environment, and the improvement of data on the resource through ongoing survey and excavation.

La diversité végétale exceptionnelle des forêts tropicales a toujours suscité une part d’incompréhension chez les scientifiques qui tentent de comprendre les processus à l’origine de cette diversité, ainsi que les mécanismes expliquant les changements spatiaux de composition spécifique. Une des clés de ce dernier mystère résiderait dans l’influence de la différentiation des niches écologiques, mais aussi de la dispersion limitée des graines et d’événements stochastiques (purement aléatoires et non prévisibles). La niche d’une espèce contraint celle-ci à s’établir dans un habitat présentant des gammes de conditions bien délimitées en termes de propriétés du sol (disponibilité en nutriments et toxicité de certains éléments) et d’intensité lumineuse. Par exemple, certaines espèces sont plus tolérantes à l’ombrage (espèces « sciaphiles ») que d’autres qui ne peuvent s’établir que dans des trouées forestières offrant suffisamment de lumière (espèces « héliophiles »). En Afrique centrale, les communautés d’arbres sont aujourd’hui en grande partie composées de ces espèces dites « héliophiles », alors que les ouvertures forestières naturelles sont rares. Il est fortement suspecté que la dominance de ces espèces soient la conséquence de trouées générées par l’homme qui, jusqu’au début de la période coloniale (vers 1900), occupait de vastes surfaces de forêt où il pratiquait l’agriculture sur brûlis. Cependant, peu d’études ont jusqu’à présent déterminé dans quelle mesure ces pratiques agricoles ont influencé la composition spécifique des forêts à l’échelle régionale comme à l’échelle locale.

L’objectif du présent travail est de faire la lumière sur l’impact de ces perturbations humaines mais aussi plus généralement sur l’influence relative de la niche écologique des espèces d’arbres par rapport à d’autres facteurs (dispersion limitée et facteurs stochastiques) sur leur distribution spatiale. Pour cela nous avons utilisé des données botaniques et environnementales provenant d’inventaires réalisés dans une forêt tropicale située en République Démocratique du Congo (quatre transects parallèles mesurant chacun 500 à 600 m de long), ainsi que des données similaires complémentées d’inventaires anthracologiques (estimation de la quantité de charbons de bois dans le sol, utilisée comme indicateur de feux passés d’origine anthropique) récoltées dans trois régions du sud du Cameroun (208 parcelles de 0,2 ha chacune).

Les données récoltées nous ont permis de mettre en évidence un impact significatif des propriétés physico-chimiques du sol sur la composition en espèces d’arbres. Plus précisément, nous avons pu constater une différence floristique marquée entre deux habitats très contrastés (sol sableux vs. sol argileux, Rép. Dém. Du Congo), et cela à une échelle spatiale locale (< 1 km²) où l’on pensait que de l’influence des facteurs stochastiques et de dispersion limitée étaient prépondérante. Mes analyses ont également démontré que cette différence était plus marquée pour les arbres de la canopée que pour les arbres des strates inférieures (« sous-canopée »), ce qui est sans doute lié au fait que de nombreux individus de la sous-canopée sont composés de juvéniles régénérant la canopée, parmi lesquels de nombreux arbres subissent une exclusion compétitive en cours (brouillant ainsi les signaux d’association espèce-habitat).

À une échelle spatiale beaucoup plus large cette fois (de 5 à 100 km, inventaires du Sud Cameroun), nous avons démontré que la diversité floristique était également influencée de manière significative par l’hétérogénéité spatiale de propriétés abiotiques du sol, notamment par les concentrations en (i) certains nutriments essentiels pouvant présenter des valeurs potentiellement limitantes (K, Mg, Ca et P) ainsi qu’en en (ii) élements pouvant être présents en quantités toxiques (Al et Mn). Cependant, alors que le signal environmental a été clairement détecté à l’échelle communautaire, seule les abondances d’une minorité d’espèces (< 15%) ont répondu significativement à la variation des conditions de sol. En outre, le nombre de réponses significatives a augmenté avec l’échelle d’observation ainsi qu’avec le degré d’hétérogénéité environnementale et/ou floristique. Pour mettre en évidence cet effet du sol, nous avons introduit une nouvelle approche permettant de tester la fraction d’une analyse de partition de variance correspondant à la part de variation floristique expliquée par l’effet de conditions édaphiques spatialement structurées (co-variation entre effets spatiaux et édaphiques), en combinant l’analyse de partition de variance avec des vecteurs propres de Moran (« Moran’s eigenvector maps ») et des translations toroïdales. Bien que cette méthode nous ait permis de déterminer si la fraction en question était significative, nous avons également mis en doute son interprétation habituelle suggérant que cette fraction représente une structure floristique directement induite par des structures spatiales de conditions de sol. Grâce à des simulations de populations végétales liées à des propriétés environnementales, nous avons mis en évidence que la valeur de la fraction étudiée ne semble finalement pas influencée par le degré de structuration spatiale des conditions environnementales, remettant donc en question l’utilité de l’analyse de partition de variance pour inférer des effets de processus écologiques sous-jacents sur la distribution spatiale des espèces d’arbres.

Enfin, les données floristiques et anthracologiques du Sud Cameroun ne nous ont pas permis de démontrer statistiquement l’hypothèse que les perturbations humaines passées sont en partie responsables de la dominance actuelle des espèces héliophiles. L’absence de corrélation significative entre l’abondance relative de ces espèces et la quantité de charbons de bois dans le sol peut s’expliquer par le fait que la majorité de ces charbons (60%) étaient trop vieux (1500 à 3000 ans) pour refléter des perturbations ayant influencé la diversité végétale présente.

Les conclusions générales de ma thèse de doctorat soutiennent que la niche écologique des espèces d’arbres des forêts tropicales africaines contribue de manière significative à déterminer leur assemblage dans l’espace, mais aussi que ces effets de niche dépendent fortement du contexte environnemental étudié ainsi que de l’échelle spatiale d’observation. Ce travail lève donc en partie un voile sur l’écologie des écosystèmes forestiers d’Afrique centrale qui restent largement méconnus par rapport à ceux d’Asie du Sud-Est et des régions néotropicales.

Doctorat en sciences, Spécialisation biologie végétale
info:eu-repo/semantics/nonPublished

Human activity can affect the soil in ways which are traceable long after the land has been given over to other uses, and past land management practices can be reconstructed by investigation of these relict characteristics. In some regions the addition of fertilising materials to the arable soils has created artificially deepened anthropogenic topsoils which can be over 1m thick. Such relict soils are found all over the world, and are widespread in north-western Europe. This work focuses on the anthropogenic soils in the Northern Isles, which were formed from the Neolithic period up until the 20th century. Three multi-period sites were investigated using thin section micromorphology, organic/inorganic phosphate analysis, soil magnetism, particle size distribution, loss on ignition and soil pH. Current views of anthropogenic soil formation, based on pedological investigation and historical documentary sources, are that they are formed as a result of the addition of domestic animal manures and turf used as animal bedding to arable areas. This project sets out to test the hypothesis that in fact anthropogenic soils are the result of a wide range of formation processes which took place over extended periods of time. The hypothesis has been tested by analysing soils and associated middens of different dates, which have been sealed and protected by blown sand deposits. The results have shown that in the Neolithic period arable soils were created by cultivating the settlement's midden heaps as well as by adding midden material to the surrounding soils. In the Bronze Age human manure, ash and domestic waste were spread onto the fields around the settlements to create arable topsoils up to 35cm thick. In the Iron Age arable agriculture was intensified by selective use of organic manures on one of the sites investigated, but organic waste material was not used as efficiently as it was in later periods, and on both sites it was allowed to accumulate within the settlements. In the Norse period, when the intensive system used in historical times appears to have originated, organic waste may have been used more efficiently. These changes appear to reflect a greater organisation of land resources and manuring strategies and increased demand for arable production over time.

Ever since the development of farming humans have been implicitly linked with the landscape. Influences include the manipulation of natural environments by woodland clearance, field developments and animal husbandry. Development can also be determined by the identification and distribution of soils developed and modified by the addition of organic and inorganic components. Anthropogenic or amended soils have been identified in many forms across north west Europe that retain distinctive physical and chemical indications of historical agrarian and settlement history. This thesis researched the on-site distribution of anthropogenic and amended soils across different landuse areas and identified and quantified a range of black carbonised particles in order to investigate their role in the soils ability to retain high elemental concentrations of manuring and elements associated with domestic activity and industrial processes. Three sites in contrasting environments were chosen for analysis; in Fair Isle, the Netherlands and Ireland on the basis of an excellent agararian and settlement history and previous analysis of anthropogenic soils. The fieldwork results showed extremly deep plaggen soils in the Netherlands but considerably shallower horizons of amended arable soils on Fair Isle and in Ireland contrary to previous analysis. There was however, clear evidence of a reduction in anthropogenic and amended soils with increased distance from the farm centres as a result of less manuring. The soil pH, organic matter, particle size, magnetic susceptibility and bulk elemental analysis results showed unexpected increases in the amended soils of Fair Isle and Ireland and reflected a similar manuring process. In the Netherlands the deep plaggen soils had very low results reflecting modern arable farming. The micromorphology results illustrated distinctive characteristics associated with localised manuring techniques. On Fair Isle and in Ireland the main organic manuring material was peat and burnt peat, whereas in the Netherlands the plaggen soils were predominantly composed of meadowland and heathland turf. At all three sites there was a large number of black carbonised and black amorphous inclusions and point counting and image analysis results showed a decrease with depth and distance from settlement nucleii mirroring the fieldwork observations. The elemental analysis conducted has proved to be an extremly useful tool for the identification of various forms of black carbon and for identifying the provenance of high elemental concentrations. The oxygen:carbon ratios confirmed the origins of organic components used in the development of the amended and anthropogenic soils and the elemental analysis showed that at each site over 80% of visually unidentifiable amorphous black carbon particles were heavily decomposed carbonised inclusions. Overall the elemental concentrations within the black carbonised particles was very low but this reflected the elemental results found in the bulk soils and the inclusions contained higher concentrations of P, Ca, K, Fe and Al and considerably lower concentrations of elements associated with domestic activity or industry Zn, Cu, Ba, Cr, As and Pb.

Globally emphasis has been given to identify emerging and re-emerging pathogens. Rapid urban expansion creates a problem which is two-fold. Firstly, increasing slum living conditions due to inadequate rate of infrastructure development results in an increased reliance on natural resources, including the capture and consumption of surrounding wildlife to subsist, thereby facilitating the transfer of emergent zoonotic pathogens. Secondly, through activities such as pollution or alien species introductions, the rapid transformation of once pristine environments, alters natural systems, potentially exposing these environments to new bacterial pathogens. Therefore, the main aim of this study was to assess overlooked bacterial species harboured by four host species (Bathyergus suillus, Georychus capensis, Cryptomys hottentotus hottentotus and Fukomys damarensis) belonging to the subterranean rodent family Bathyergidae, which inhabit an environment well-suited for an array of bacterial species, and which varied in their exposure to human settlements. Bacterial prevalence and diversity was initially evaluated using broad-range PCR techniques in combination with nucleotide sequencing. This revealed high levels of bacterial prevalence (82.91%) and mixed infections (22.60%) in bathyergid species. Two bacterial groups, the Bacillus cereus complex (a group of soil-dwelling bacterial strains with pathogenic potential with an overall prevalence of 8.55%) and haemotropic Mycoplasma strains (vector-borne bacterial strains of zoonotic potential with an overall prevalence of 1.28%) were subsequently selected for further genetic analysis with genus and species-specific PCRs. Bacillus molecular screening and phylogenetic analyses was achieved by targeting four gene regions with seven published primer assays and two novel PCR assays. This enabled identification of two B. cereus complex strains in bathyergid lungs and revealed an overall B. cereus complex prevalence of 17.95% for the 234 bathyergid lung samples screened. Bacillus genome prevalence was significantly higher in B. suillus individuals (45.35%), sampled in a peri-urban environment, compared to the other bathyergid species sampled from pristine habitats (ranging from 0% - 4.44%). Anthropogenic activities in the area where B. suillus was sampled could, at least partially, attribute to the perceived difference between urban and naturally sampled bathyergid species, highlighting the role of B. suillus to act as both a reservoir of potentially zoonotic pathogens and as a sentinel for anthropogenic soiling. Mycoplasma molecular screening using three different PCR assays, all targeting the 16S rRNA gene region, confirmed an overall haemotropic Mycoplasma prevalence of 24.13% in the 286 bathyergid organs (lung, spleen and liver) screened. A significantly higher prevalence and diversity of haemotropic Mycoplasma strains was found in B. suillus lungs (41.86%) compared to its naturally occurring relatives (ranging from 0%-36%). Phylogenetic analyses identified six novel haemotropic Mycoplasma strains, all grouping within a discrete monophyletic cluster, sister to Mycoplasma coccoides, and comprising two well-supported sub-clusters. The human introduction of commensal rodents harbouring Mycoplasma strains transferred through cosmopolitan arthropod vectors to indigenous bathyergids, likely underlies the higher prevalence in urban areas, although other biotic and abiotic factors affecting ectoparasite load also merit consideration. The data generated by the current study indicate the need to identify largely overlooked and potentially zoonotic bacterial pathogens in subterranean mammals and emphasises the importance of monitoring anthropogenically-introduced, opportunistic pathogens and the threats they pose to vulnerable communities and co-occurring, free-living animal species
Dissertation (MSc)--University of Pretoria, 2017.
Airports Company of South Africa (ACSA)
National Research Foundation (NRF)
Zoology and Entomology
MSc
Unrestricted

Anthropogenic driven soil erosion has increased drastically within the last few centuries. Accelerated removal of topsoil degrades soil characteristics, decreasing the agricultural capacity to sustain food production for future human generations. In order to reduce sediment erosion to a minimum, soil movement dynamics have to be understood over relevant timescales. Emphasis is required on human land use, which has changed over time, altering erosion and deposition processes in the landscape. This thesis aims to understand the development of erosion with time and studies the effects of the anthropogenic impact on the Earth’s surface. A case study was conducted in the Christina River Basin in south-eastern Pennsylvania (USA) to evaluate the anthropogenic impact on sediment redistribution before and during European colonisation of the US East Coast. The Christina River Basin is focus of the Christina River Basin Critical Zone Observatory, where researchers of many disciplines (e.g. hydrology, geochemistry, geology, biology, geomorphology, soil science) study the interactions of the water, mineral and carbon cycle in relation to different land uses. This site is particularly suitable for this study due to the sudden change in land use with the arrival of European Settlers and the well-recorded history of land use in the area since. Besides sediment processes related to the European colonisation, special emphasis was placed on the last century and the particular impact of land management practices on the landscape. For the approach of this study, upland and depositional sediment profiles, as well as suspended sediment collected from rivers at different times were analysed for radionuclide activity. In particular, a combination of the short-lived radionuclides 7Be, 210Pb, and 137Cs with the long-lived meteoric nuclide 10Be was used to allow detection of sediment erosion as well as tracing of sediment source to streams over different time frames. Natural sediment processes were studied by investigating meteoric 10Be in different upland and valley hollow soil profiles in the Christina River Basin. Natu-ral sediment erosion rates of 17 to 18 mm per 1000 years and soil residence time of 26,000 to 57,000 years in upland sites classify the region to be characterised by slowly eroding soils. Valley hollow study sites indicate an alteration in sediment supply due to climate change within the last 80,000 years. Analysis of meteoric 10Be on suspended sediment in rivers with time (from pre-colonial to present times) and a comparison to the historical background of land use management indicated drastic changes in the sediment sources to the streams during the colonisation of the US East Coast. Such profound changes in the soil movement dynamics can be tied to a complete deforestation of the watershed during that time. However, a slow recovery of sediment sources to pre-colonial conditions within the last 100 years was observed, which may be related to the afforestation in parts of the watershed and change in farming practises. Examination of floodplains in recent history (last 100 years) using 210Pb and 137Cs identified a correlation between changes in land use and floodplain development. In particular, deforestation led to channel migration within the watershed, whereas afforestation reduced the flood magnitude. A discrimination of different sediment sources (agricultural and forest surface, channel migration) was detected on present suspended sediment by using a combination of tracers: 7Be, 137Cs, 210Pb and 10Be. About 50 % of sediment in the stream was attributed to channel migration classifying the stream as relatively unstable, whereas the second major sediment contribution was agricultural soil (32 %). As both sources are closely related to human activity in the study area, appropriate land management practices and stream channel stabilisation are of great importance for a hydro- and morphodynamic balance in future times. Results presented in this study provide evidence of the powerful impact anthropogenic land use has had on sediment movement in the Christina River Basin. More importantly, this study has shown the usefulness of combining long- and short-lived radionuclides to identify soil redistribution at different time periods and scales. Radionuclide data does not only reflect the drastic impact during European colonisation but also detects gradual changes that occur due to human action to limit soil erosion within the last century. This study indicates that some of the best management practices may minimise anthropogenic induced soil erosion, whilst simultaneously signifying the need to further improve land use management and reduce sediment erosion.

El reg és el principal consum antropogènic d'aigua dolça. Es preveu que l'explotació dels recursos hídrics per a millorar la producció d'aliments mitjançant pràctiques de reg seguirà augmentant en els propers decennis. De fet, es preveu que el creixement demogràfic i els canvis climàtics exerceixin una pressió encara més gran sobre els recursos hídrics disponibles. Tot i que el reg té conseqüències directes en la gestió racional dels recursos hídrics, així com en la producció d'aliments, cal un coneixement detallat dels llocs en què realment es rega a tot el món i de quanta aigua s'utilitza realment per les pràctiques de reg. En aquesta investigació s'han elaborat mètodes per detectar i cartografiar les zones on realment es rega, així com mètodes per estimar les quantitats d'aigua que s'apliquen per al reg; les metodologies proposades utilitzen dades d'humitat del sòl provinents de la teledetecció espacial. En aquesta investigació s'han adoptat dos casos d'estudi: el primer es troba a la conca de l'Ebre, al nord-est d'Espanya, mentre que l'altre és la conca de l'Alt Tíber, a Itàlia central. S'han assajat diversos productes d'humitat del sòl obtinguts per teledetecció amb diferents resolucions espacials per avaluar els que millor funcionen en la detecció de reg i, per tant, en la cartografia de les zones de regadiu. A més, s'han realitzat estimacions quantitatives de les quantitats d'aigua aplicades per al reg. L'activitat de detecció i cartografia del reg s'ha dut a terme en els dos casos d'estudi. En l'espanyol s'ha avaluat inicialment la capacitat de detecció de reg de diversos productes de teledetecció. S'han avaluat els següents jocs de dades d'humitat del sòl: SMAP (Soil Moisture Active Passive) a 1 km i 9 km, SMOS (Soil Moisture and Ocean Salinity) a 1 km, Sentinel-1 a 1 km, i ASCAT (Advanced SCATterometer) a 12,5 km. Les versions d'1 km de SMAP i SMOS s'obtenen mitjançant la desagregació amb el mètode DISPATCH (DISaggregation based on Physical And Theoretical scale CHange). La detectabilitat del reg pels productes considerats s'ha avaluat mitjançant índexs derivats de la teoria d’estabilitat temporal aquí utilitzada sota aquesta nova perspectiva. A més, s'han elaborat mapes de les zones irrigades produïts a través de l'algoritme d'agrupament K-mitjanes. A les zones agrícoles de la conca de l'Alt Tíber, a Itàlia, s'ha realitzat una anàlisi a doble escala. En l'anàlisi a 1 km de resolució espacial s'ha aplicat el mateix procediment adoptat en el cas d'estudi de la conca de l'Ebre per avaluar la detectabilitat del regadiu mitjançant la humitat del sòl provinent de la teledetecció. S'han utilitzat els següents productes: SMAP a 1 km, la versió Sentinel-1 a 1 km publicada pel Copernicus Global Land Service, i una versió Sentinel-1 a escala de la parcel·la (produïda per THEIA) agregada a 1 km. Cal observar que els dos primers productes són els mateixos que també s’han utilitzat en el cas d'estudi espanyol. En aquesta anàlisi, així com en la realitzada sobre l'àrea d'estudi a la conca de l'Ebre, s'ha utilitzat com a suport el model de superfície continental SURFEX-ISBA (Surface EXternalisée - Interaction Sol Biosphère Atmosphère). En l'anàlisi a escala de parcel·la, les dades de THEIA Sentinel-1 agregades a 100 m s'han utilitzat per produir mapes d'alta resolució de les zones de regadiu mitjançant l'algoritme d'agrupament K-mitjanes. L'activitat de quantificació del reg s'ha dut a terme a la zona d'estudi a la conca de l'Ebre únicament; s'han realitzat dos experiments: un utilitzant SMAP amb dades a 1 km de resolució i un altre utilitzant SMOS amb dades a 1 km. Tots dos conjunts de dades s'han utilitzat per forçar l'algoritme SM2RAIN adaptat a l'estimació del reg. En l'algoritme s'ha aplicat una modelització més realista del terme d’evapotranspiració per reproduir adequadament l'evapotranspiració dels cultius segons el model de la FAO (Organització de les Nacions Unides per a l'Agricultura i l'Alimentació). Les anàlisis realitzades tenen per objecte satisfer les llacunes existents en el camp de la recerca relacionada amb el reg; els resultats obtinguts són útils per avaluar l'impacte de les pràctiques de reg en el cicle hidrològic.
El riego es el principal consumo antropogénico de agua dulce. Se prevé que la explotación de los recursos hídricos para mejorar la producción de alimentos mediante prácticas de riego seguirá aumentando en los próximos decenios. De hecho, se prevé que el crecimiento demográfico y los cambios climáticos ejerzan una presión aún mayor sobre los recursos hídricos disponibles. A pesar de que el riego tiene consecuencias directas en la gestión racional de los recursos hídricos, así como en la producción de alimentos, falta un conocimiento detallado de los lugares en los que realmente se riega en todo el mundo y de cuánta agua se utiliza realmente para las prácticas de riego. En esta investigación se han elaborado métodos para detectar y cartografiar las zonas donde realmente se riega, así como métodos para estimar las cantidades de agua que se aplican para el riego; las metodologías propuestas utilizan datos de humedad del suelo provenientes de la teledetección espacial. En esta investigación se han adoptado dos casos de estudio: el primero se sitúa en la cuenca del Ebro, en el noreste de España, mientras que el otro es la cuenca del Alto Tíber, en Italia central. Se han ensayado varios productos de humedad del suelo obtenidos por teledetección con diferentes resoluciones espaciales para evaluar los que mejor funcionan en la detección del riego y, por lo tanto, en la cartografía de las zonas de regadío. Además, se han realizado estimaciones cuantitativas de las cantidades de agua aplicadas para el riego. La actividad de detección y cartografía del riego se ha llevado a cabo en ambos casos de estudio. En el español se ha evaluado inicialmente la capacidad de detección de riego de varios productos de teledetección. Se han evaluado los siguientes conjuntos de datos de humedad del suelo: SMAP (Soil Moisture Active Passive) a 1 km y 9 km, SMOS (Soil Moisture and Ocean Salinity) a 1 km, Sentinel-1 a 1 km, y ASCAT (Advanced SCATterometer) a 12,5 km. Las versiones de 1 km de SMAP y SMOS se obtienen mediante la desagregación con el método DISPATCH (DISaggregation based on Physical And Theoretical scale Change). La detectabilidad del riego por los productos considerados se ha evaluado mediante índices derivados de la teoría de la estabilidad temporal aquí utilizada bajo esta nueva perspectiva. Además, se han elaborado mapas de las zonas irrigadas producidos a través del algoritmo de agrupamiento K-medias. En las zonas agrícolas de la cuenca del Alto Tíber, en Italia, se ha realizado un análisis a doble escala. En el análisis a 1 km de resolución espacial, se ha aplicado el mismo procedimiento adoptado en el caso de estudio de la cuenca del Ebro para evaluar la detectabilidad de la irrigación mediante la humedad del suelo por teledetección. Se han utilizado los siguientes productos: SMAP a 1 km, la versión Sentinel-1 a 1 km entregada por el Copernicus Global Land Service, y una versión Sentinel-1 a escala de parcela (producida por THEIA) agregada a 1 km. Obsérvese que los dos primeros productos son los mismos que también se utilizaron en el caso de estudio español. En este análisis, así como en el realizado sobre el área de estudio en la cuenca del Ebro, se ha utilizado como soporte el modelo de superficie terrestre SURFEX-ISBA (SURface EXternalisée - Interaction Sol Biosphère Atmosphère). En el análisis a escala de parcela, los datos del THEIA Sentinel-1 agregados a 100 m se han utilizado para producir mapas de alta resolución de las zonas de regadío mediante el algoritmo de agrupamiento K-medias. La actividad de cuantificación del riego se ha llevado a cabo en la zona de estudio de la cuenca del Ebro únicamente; se han realizado dos experimentos: uno explotando SMAP con datos a 1 km de resolución y otro explotando SMOS con datos a 1 km. Ambos conjuntos de datos se han utilizado para forzar el algoritmo SM2RAIN adaptado a la estimación del riego. En el algoritmo se ha aplicado una modelización más realista del término de evapotranspiración para reproducir adecuadamente la evapotranspiración de los cultivos según el modelo de la FAO (Organización de las Naciones Unidas para la Agricultura y la Alimentación). Los análisis realizados tienen por objeto colmar las lagunas existentes en el campo de la investigación relacionada con el riego; los resultados obtenidos son útiles para evaluar el impacto de las prácticas de riego en el ciclo hidrológico.
Irrigation is the primary source of anthropogenic freshwater consumptions. The exploitation of water resources to improve the food production through irrigation practices is expected to further increase in the upcoming decades. In fact, the population growth and climate changes are expected to put even more pressure on the available water resources. Despite irrigation having direct implications on the rational management of water resources, as well as on food production, a detailed knowledge of where irrigation actually occurs worldwide and of how much water is actually used for irrigation practices is missing. In this research, approaches to detect and map areas where irrigation actually occurs, as well as methods to estimate the amounts of water applied for irrigation, have been developed; the proposed methodologies exploit remote sensing soil moisture. Two case studies have been considered in this research: the first one is located within the Ebro basin, in North-eastern Spain, while the other one is the Upper Tiber basin, in central Italy. Several remotely sensed soil moisture products at different spatial resolutions have been tested to evaluate the best performing ones in detecting irrigation signals and thus mapping irrigated areas. In addition, quantitative estimates of the water amounts applied for irrigation have been performed. The irrigation detection and mapping activity has been carried out over both case studies. In the Spanish one, the capability to detect irrigation of several remote sensing products has been initially assessed. The following soil moisture data sets have been evaluated: SMAP (Soil Moisture Active Passive) at 1 km and 9 km, SMOS (Soil Moisture and Ocean Salinity) at 1 km, Sentinel-1 at 1 km, and ASCAT (Advanced SCATterometer) at 12.5 km. The 1 km versions of SMAP and SMOS are obtained through downscaling with the DISPATCH (DISaggregation based on Physical And Theoretical scale CHange) method. The detectability of irrigation by the considered products has been assessed through indices derived from the temporal stability theory here used under this new perspective. Furthermore, maps of irrigated areas have been produced through the K-means clustering algorithm. Over the agricultural areas in the Upper Tiber basin, in Italy, a double-scale analysis has been carried out. In the analysis at 1 km spatial resolution, the same procedure adopted over the case study in the Ebro basin to evaluate the detectability of irrigation through remotely sensed soil moisture has been applied. The following products have been used: SMAP at 1 km, the Sentinel-1 at 1 km version delivered by the Copernicus Global Land Service, and a plot-scale-born Sentinel-1 version (produced by THEIA) aggregated at 1 km. Note that the first two products are the same used over the Spanish case study also. In this analysis, as well as in the one carried out over the study area in the Ebro basin, surface soil moisture simulated by the SURFEX-ISBA (SURface EXternalisée - Interaction Sol Biosphère Atmosphère) land surface model has been used as support. In the plot-scale analysis, THEIA Sentinel-1 data aggregated at 100 m have been used to produce high-resolution maps of irrigated areas through the K-means clustering algorithm. The irrigation quantification activity has been carried out over the study area in the Ebro basin only; two experiments have been performed: one exploiting SMAP at 1 km data and another one exploiting SMOS at 1 km data. Both data sets have been used to force the SM2RAIN algorithm adapted to estimate irrigation. A more realistic modeling of the evapotranspiration term has been implemented into the algorithm to properly reproduce the crop evapotranspiration according to the FAO (Food and Agriculture Organization) model. The analyses carried out are aimed at filling the existing gaps in the irrigation-related research field; the obtained results are useful to assess the impact of irrigation practices on the hydrological cycle.
L’irrigazione è la principale fonte di consumo di acqua dolce. Nei prossimi decenni è atteso un ulteriore sfruttamento della risorsa idrica per incrementare la produzione di cibo attraverso le pratiche irrigue. Si stima infatti che la crescita della popolazione e i cambiamenti climatici possano esercitare una pressione ancora maggiore sulle risorse idriche disponibili. Nonostante le importanti implicazioni che ha l’irrigazione sulla gestione razionale dell’acqua e sulla produzione di cibo, non si ha una conoscenza dettagliata di dove l’irrigazione effettivamente avvenga nel mondo e di quanta acqua venga effettivamente utilizzata per le pratiche irrigue. In questa ricerca sono stati sviluppati approcci per rilevare e mappare le aree dove effettivamente si verifica l’irrigazione e per stimare i volumi irrigui; le metodologie proposte sfruttano l’umidità del suolo rilevata da satellite. In questa ricerca sono stati considerati due casi di studio: il primo si trova nel bacino del fiume Ebro, nel Nord-Est della Spagna, mentre l’altro è il bacino superiore del Tevere, nell’Italia centrale. Diversi prodotti di umidità del suolo da satellite, caratterizzati da diverse risoluzioni spaziali, sono stati valutati al fine di determinare i più performanti nel rilevare segnali di irrigazione e quindi mappare le aree irrigate. Inoltre, sono state eseguite stime quantitative dei volumi di acqua utilizzati per pratiche irrigue. L’attività di rilievo e mappatura dell’irrigazione è stata condotta su entrambe le aree pilota. In quella spagnola, è stata valutata la capacità di rilevare l’irrigazione di diversi prodotti di umidità del suolo. Sono stati considerati i seguenti set di dati: SMAP (Soil Moisture Active Passive) a 1 km e 9 km, SMOS (Soil Moisture and Ocean Salinity) a 1 km, Sentinel-1 a 1 km e ASCAT (Advanced SCATterometer) a 12.5 km. Le versioni a 1 km di SMAP e SMOS sono ottenute tramite disaggregazione eseguita con il metodo DISPATCH (DISaggregation based on Physical And Theoretical scale CHange). La capacità di rilevare l’irrigazione da parte dei prodotti considerati è stata valutata tramite indici derivanti dalla teoria della stabilità temporale e usati in questo studio sotto una nuova prospettiva. Inoltre, sono state prodotte delle mappe delle aree irrigate attraverso l’algoritmo di classificazione K-means. Un’analisi a doppia scala spaziale è stata condotta sulle aree agricole all’interno del bacino superiore del Tevere, in Italia. Nell’ambito dell’analisi alla risoluzione spaziale di 1 km, è stata applicata la stessa procedura già adottata per il caso di studio nel bacino dell’Ebro per valutare la possibilità di rilevare l’irrigazione tramite umidità del suolo da satellite. Sono stati utilizzati i seguenti prodotti: SMAP a 1 km, la versione a 1 km di Sentinel-1 fornita da Copernicus Global Land Service e una versione di Sentinel-1 originariamente prodotta de THEIA alla scala di parcella e aggregata a 1 km. Va sottolineato che i primi due prodotti menzionati sono stati utilizzati anche sull’area pilota in Spagna. Sia in questa analisi che in quella condotta nel bacino dell’Ebro, dati di umidità del suolo superficiale modellati tramite il modello di superficie terrestre SURFEX-ISBA (SURface EXternalisée - Interaction Sol Biosphère Atmosphère) sono stati utilizzati come supporto. Nell’analisi alla scala di parcella, sono stati impiegati i dati di Sentinel-1 prodotti da THEIA e aggregati a 100 m al fine di produrre mappe di aree irrigate ad alta risoluzione tramite l’algoritmo di classificazione K-means. L’attività di quantificazione dell’irrigazione è stata finalizzata solamente per l’area pilota nel bacino dell’Ebro; sono stati condotti due esperimenti: uno utilizzando i dati da SMAP a 1 km e un altro sfruttando i dati da SMOS a 1 km. Entrambi i set di dati sono stati utilizzati per forzare la versione dell’algoritmo SM2RAIN adattata per la stima dell’irrigazione. Una modellazione più realistica dell’evapotraspirazione è stata implementata nell’algoritmo al fine di riprodurre adeguatamente l’evapotraspirazione delle colture secondo il modello FAO (Food and Agriculture Organization). Le analisi condotte sono finalizzate a colmare le lacune esistenti nel campo di ricerca relativo all’irrigazione; i risultati ottenuti sono utili per valutare l’impatto delle pratiche irrigue sul ciclo idrologico.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
Irrigation is an essential input that has enhanced, substantially, food production and has improved economic development in arid regions. Irrigation, also, has generated negative impacts to the environment and to human health. The aim of this work was to quantify and qualify the irrigation impacts and of the climatic seasonality over soil and water resource in Irrigated District of Baixo AcaraÃ, CearÃ, Brazil. Ten points spread out over the studied area were selected as monitoring stations. Two of them were sited in irrigated fields. Samples were collected monthly from Dezember/2003 to November/2005, November/2006, March and May/2007. The samples were analyzed for: pH, electrical conductivity (EC), Ca2+, Mg2+, Na+, K+, HCO3 -, PO4 -2, Cl-, NH4 +, NO3 -, SO4 -2 and Sodium Adsorption Ratio (SAR). Soil samples were collected in two different types of land use: irrigated field and uncultivated area field. Soils samples were taken for each 50 cm until water table (7 m) was reached, during wet and irrigation seasons. Multivariate statistical method, cluster analysis, was applied to classify the shallow wells inte similar groups in relation to water quality. To identify spacial variability of Na+, Cl-, CE, PO4 -2 e NO3 - in the water table it was used a GIS platform and the software: Global Mapper 5.0, ArcGis 9.1. The geostatistic process was performed using the Surfer 7.0. According to the results the highest values of changeable bases (Ca2+, Mg2+, Na+ e K+), Cl-, SAR AND NO3 - were presented in the water of P1 (sample station 1). These values were over the acceptable limit of Class 1 defined by CONAMA (Resolution 357/05). The analyzed variables showed a high spacial variability and a low temporal variability. The used soil management in the irrigated field, where shallow wells (P3 and P4) were sited, is not contributing to the contamination or water table by salts, yet. Also, the results show have that irrigation caused the groundwater concentration of NO3âN to increase from 1.52 to 19.3 mg L-1, thereby, exceeding the standards of the World Health Organization (WHO).
A irrigaÃÃo se constitui em um importante fator que contribui para a seguranÃa alimentar e possibilita o desenvolvimento econÃmico de muitas regiÃes, principalmente Ãridas e semi-Ãridas. Entretanto, se nÃo manejar adequadamente poderà vir a acarretar danos irreversÃveis ao meio ambiente com potenciais riscos à saÃde humana. Este trabalho teve por objetivo quantificar e qualificar o efeito da irrigaÃÃo e da sazonalidade climÃtica nos recursos solo e Ãgua do Distrito Irrigado do Baixo Acaraà â DIBAU, CearÃ. Foram selecionados 10 poÃos rasos como estaÃÃes de coletas de Ãgua, dos quais 2 (dois) estÃo inseridos no perÃmetro de irrigaÃÃo. As coletas de Ãgua foram realizadas mensalmente de dezembro de 2003 a novembro de 2005, novembro de 2006, marÃo e maio de 2007. As anÃlises quÃmicas foram realizadas no LaboratÃrio de Solo e Ãgua da EMBRAPA AgroindÃstria Tropical. Foram analisados: pH, CEa, Ca2+, Mg2+, Na+, K+, HCO3 -, PPO4 -, Cl -, NH4 +, NO3 -, SO4 -2 e RAS. As coletas de solo foram efetuadas em 2 pontos amostrais inseridos nas imediaÃÃes de dois dos 10 poÃos estudados, ambas coletadas no perÃodo seco e chuvoso, a cada 50 cm de profundidade da superfÃcie atà a zona de saturaÃÃo do lenÃol freÃtico. Para se classificar os poÃos em grupos de categorias semelhantes quanto à qualidade da Ãgua empregou-se a tÃcnica de estatÃstica multivariada, analise de agrupamento, empregando-se o pacote estatÃstico SPSS 13.0. Empregou-se tambÃm a plataforma SIG e os softwares: Global Mapper 5.0, ArcGis 9.1 e o Surfer 7.0 no processamento da geoestatÃstica para determinaÃÃo da variabilidade espacial do Na+, Cl-, CE, P-PO4 - e NO3 - na Ãgua do lenÃol freÃtico; como tambÃm para determinaÃÃo da direÃÃo da linha de fluxo do lenÃol freÃtico. Pelos resultados obtidos,verifica-se que as Ãguas do P1(Alparcatas) destacam-se por apresentar os valores mais elevados das bases trocÃveis (Ca2+, Mg2+, Na+ e K+), Cl-, RAS e NO3-, concentraÃÃes sempre acima dos limites mÃximos aceitÃveis para Classe 1 da ResoluÃÃo 357/05 do CONAMA. Ocorreu uma grande variabilidade espacial entre os poÃos estudados para as variÃveis analisadas, ademais nÃo se observou variabilidade temporal. O manejo praticado nos solos onde estÃo inseridos os poÃos P4 e P5, perÃmetro irrigado, por ainda nÃo estarem contribuindo com a contaminaÃÃo de sais na Ãgua do lenÃol freÃtico do DIBAU. Jà se percebe um aumento preocupante dos teores de nitrato nas Ãguas dos poÃos influenciados pela agricultura irrigada (P4 e P5), excedendo significativamente aos limites mÃximos aceitÃveis pela ResoluÃÃo 357/05 e pela Portaria 518/2004 para consumo humano.

Plazas and patios were important spaces for expressing power and social identity in prehispanic Mesoamerica. However, plazas can be analytically problematic, because they were often kept clean of material debris. Previous geoarchaeological studies of anthropogenic soils and sediments have shown that specific activities leave characteristic chemical signatures on prepared earthen surfaces. The research presented here uses soil chemical residue analysis and excavation data to examine use patterns in the North Plaza of Palmarejo, Honduras during the Late Classic period. The goal is to determine whether the plaza was used for residential or ceremonial purposes. The chemical results indicate that activities in the northern half of the plaza were distinct from those that occurred in the southern half. These results, along with the artifact assemblage recovered from excavations, suggest ceremonial use. Additionally, this research compares various soil properties, including pH and organic matter, from the North Plaza to broaden our reach in prospecting for activity loci using soil chemistry. Recent studies tend to rely on spatial differences in elemental concentrations for identifying activity patterns in the archaeological record. However, other related soil properties sometimes correlate with chemical residues, especially phosphates. The research presented explores these interconnections with the greater goal of identifying the ways and extent to which various soil properties are linked in the formation and preservation of ancient activity loci. Results suggest that the deposition and adsorption of chemical residues in anthropogenic soils at Palmarejo are generally too variable to be accurately characterized by either pH or organic matter. Chemical elements may best reveal the use of the North Plaza in antiquity.

I estimated patterns of shorebird abundance and species diversity in the Colorado River Delta and Upper Gulf of California wetlands in order to determine the relative contribution of intertidal wetlands and non-tidal anthropogenic wetlands to support shorebird habitat use. Species richness varied from 15 to 26 species among sites and 29 species were detected across sites. Density during the peak migration month was higher at the anthropogenic wetland Cienega de Santa Clara (mean = 168 ind/ha, 95% C.I. 29-367), and the intertidal Golfo de Santa Clara (mean = 153 ind/ha, 95% C.I. 17-323). Anthropogenic wetlands (playa and lagoons) supported high abundance of shorebirds along with intertidal wetlands in the Colorado River Delta (mudflats). In contrast, intertidal wetlands farther south on the Sonoran Coast presented lower abundance but higher diversity of shorebird, likely as a result of the higher diversity of habitats (rocky shore, sandy beach, estuary). I modeled water management scenarios for the Cienega in order to determine the response of the dominant vegetation (southern cattail, Typha domingensis Pers.) and the area of the outflow pool below the marsh to different scenarios of water management. The model indicates that if the inflow rate is reduced below the current 4-5 m³s⁻¹ the vegetated area of the Cienega that supports habitat for marsh birds would decrease in proportion, as would the area of the outflow pool in the Santa Clara Slough identified previously as shorebird habitat. Increases in salinity will also reduce the vegetated area due to the low salt tolerance of T. domingensis. In winter about 90% of inflow water exits the Cienega into the Santa Clara Slough due to low evapotranspiration contributing to inundate areas that are used by wintering and migrating shorebirds. Lastly, I explored the feasibility of using Vegetation Indices (NDVI and EVI) to model Yuma Clapper Rail detections in the Cienega de Santa Clara as well as the effects of adding other habitat variables and the presence of fire events in the performance of linear models based on NDVI. Both NDVI and EVI were positively related to the Yuma Clapper Rail detections. The relationship was weak to moderate, but significant (P<0.001), which suggests other factors besides the vegetation condition play an important role in the bird distribution pattern. A model including all the variability among years was a better predictor of the rails detected per transect, than models for fire and non-fire years. We did not find a significant effect from adding habitat features (water % or vegetation %), and we recommend to include variables at both microhabitat level and landscape level, relevant before and during the breeding season in order to increase the explanatory power of models.

Suite à des usages intensifs d’origines industrielles, des surfaces considérables de sols dégradés, peu fertiles, voire contaminés sont délaissées. Dans un contexte de raréfaction des sols et de pressions foncières et économiques grandissantes, la réhabilitation de ces sols fortement anthropisés et délaissés peut-être un enjeu. Toutefois, pour envisager une réutilisation de ces sols, il est nécessaire de mieux les caractériser. L’étude de la qualité des sols prend rarement en compte la biodiversité et le fonctionnement biologique. Ainsi, l’objectif de ce travail de thèse était de caractériser des sols délaissés, en prenant en compte leurs paramètres abiotiques, biotiques et fonctionnels. Pour cela, six sols fortement anthropisés délaissés du nord-est de la France, correspondant à différentes activités industrielles, ont été étudiés in situ et en laboratoire. Plusieurs groupes biotiques (bactéries, champignons, mésofaune, macrofaune et flore) ont été étudiés afin d’avoir une approche quasi-exhaustive de la biodiversité des sols. Une approche taxonomique et fonctionnelle (basée sur les traits) de la biodiversité a été réalisée pour les champignons, la méso- et la macrofaune. De plus, l’évolution in situ au cours du temps des paramètres abiotiques et biotiques a été prise en compte sur un des six sols délaissés étudiés. Enfin, les interactions biotiques entre une espèce de collembole, de champignon mycorhizien à arbuscules et de plante herbacée ont été étudiées dans deux sols délaissés, en laboratoire. Nous avons montré que les sols délaissés étaient caractérisés par une biodiversité significative, comparable selon les cas, à celles d’autres types de sols, comme les sols forestiers, de prairies ou agricoles. Toutefois, des différences de densité, de richesse et de structures taxonomiques et fonctionnelles entre les sols délaissés existent et dépendent du groupe biotique étudié. Ces différences sont notamment liées aux propriétés physico-chimiques contrastées de ces sols. Ainsi, un sol construit, amendé en compost, était l’écosystème le moins perturbé des sols étudiés, contrairement à un autre sol construit et contaminé en métaux lourds. Nous avons montré que les paramètres physico-chimiques, et surtout biologiques, évoluaient rapidement au cours du temps (environ un an) dans le sol construit contaminé en métaux lourds. Enfin, nous avons mis en évidence, dans les deux sols étudiés en laboratoire, des modifications des interactions biotiques sous l’influence de nombreux paramètres comme le volume de sol, la durée de l’interaction, la présence d’une microflore indigène etc. Finalement, nous avons montré que ces sols pouvaient être le support de services écosystémiques tels que l’habitat pour la biodiversité et qu’ils pouvaient être fonctionnels, permettant ainsi de considérer leur potentielle valorisation
Due to industrial activities intensification, large surfaces of degraded soils, with low fertility and sometimes contamination, are derelict. In the context of land depletion and economic pressure, the rehabilitation of these derelict anthropogenic soils could be a key issue. However, these derelict soils needs to be better characterized before to consider their potential use. Soil quality studies rarely take into account the biodiversity and the biological functioning. Thus, the aim of this PhD work was to characterize derelict soils by considering their abiotic, biotic and functional parameters. To this end, six derelict strongly anthropogenic soils from north-eastern France, resulting from different industrial activities, were studied in situ and in laboratory. Several biotic components (bacteria, fungi, mesofauna, macrofauna and flora) were studied to have an almost complete approach of the soil biodiversity. Taxonomical and functional (trait-based approach) study of biodiversity was performed for fungi, meso- and macrofauna. Moreover, the in situ evolution over time of abiotic and biotic parameters was taken into account in one of the six studied derelict soils. Lastly, biotic interactions between a species of Collembola, of arbuscular mycorrhizal fungi and of herbaceous plant were studied in two derelict soils, in a growth chamber. We showed that derelict soils were characterized by a significant biodiversity, comparable case to case with other kinds of soils like forest, grassland or crop. Nevertheless, differences in terms of density, richness and taxonomical and functional structure community were observed between soils and depend on considered biotic group. These differences were notably linked with contrasting physico-chemical parameters between soils. Thus, a compost-amended constructed soil was the less disturbed among the six studied soils, in contrast with a heavy metal-contaminated constructed soil. We showed that abiotic parameters, notably biotic parameters, evolved quickly (within one year) in the metal-contaminated constructed soil. In the two derelict soils where interactions between Collembola and mycorrhizal fungi were studied, biotic interactions were affected by several parameters like soil volume, time of interaction, indigenous microflora presence etc. Finally, we have shown that these derelict soils support ecosystems services such as biodiversity reserve and could be functional, allowing potential re-use

Though some researchers have argued that the Big Barrens grasslands of Kentucky were the product of anthropogenic land clearing practices by Native Americans, heretofore, this hypothesis had not been tested archaeologically. More work was needed to refine chronologies of fire activity in the region, determine the extent to which humans played a role in the process, and integrate these findings with the paleoenvironmental and archaeological record. With these goals in mind, I conducted archaeological and geoarchaeological investigations at Crumps Sink in the Sinkhole Plain of Kentucky. The archaeological record and site formation history of Crumps Sink were compared with environmental and archaeological data from the Interior Low Plateaus and Southern Appalachian Mountains for an understanding of how the site fits into the larger story of human-environmental interactions in the Eastern Woodlands. Based on the data recovered, I argue that through land burning Archaic hunter-gatherers were active managers of ecosystems to a greater degree than previously acknowledged. Excavations at Crumps Sink revealed stratified archaeological deposits spanning the late Middle Archaic to Terminal Late Archaic periods. Radiocarbon dates and an analysis of projectile point typologies provided information on the chronological and cultural history of the site. Magnetic susceptibility, loss-on-ignition, plant available phosphorous, and soil micromorphological analyses were conducted to examine landform dynamics in response to environmental change and to trace the anthropogenic signature created by human activities at the site. Masses of lithic debitage, animal bone, and burned sediment nodules per ten-cm-level provide an indication of human occupation intensity and shifting activities over time. Radiocarbon dates were used to reconstruct rates of sediment accumulation in the sink. These varying datasets were considered together for a holistic understanding of localized environmental and anthropogenic impacts on the landform. Between 7200 and 5600 cal. BP, during the Middle Holocene Thermal Maximum and corresponding with the late Middle Archaic period, sediment accumulation was sustained with one identifiable episode of very weak soil development. Background magnetic and chemical signatures in the soils were greater than they were at pre-occupation levels, demonstrating that human activities left a lasting imprint in soils as early as the late Middle Archaic period. Between 5600 and 3900 cal. BP, periods of diminished sedimentation led to more pronounced episodes of soil formation. However, these soil horizons are interposed by pulses of enhanced sediment accumulation. These soil data may signal shifting environmental regimes during the Middle to Late Holocene transition. Between 5600 and 3900 cal. BP scattered plant ash, elevated masses of burned sediment nodules, and pestle fragments in Late Archaic deposits suggest that hunter-gatherers were intensively processing nut mast, potentially in association with early forest clearance and silviculture. Botanical assemblages from a coincident archaeological sequence at the Carlston Annis site in the nearby middle Green River region has demonstrated woodland disturbance and potential silviculture in central Kentucky during this time. During the Late Archaic and Terminal Late Archaic periods (3900-3000 cal. BP), substantial plant ash deposition occurred in a stratum that accumulated relatively quickly. Very low burned sediment nodule masses in this deposit indicate that combustion features were not common in the immediate vicinity and that elevated frequencies of plant ash were the result of burning on a broader expanse of the surrounding landform. Chronologically, the zone with enhanced plant ash deposition is coeval with previously demonstrated occurrences of increased forest fires, grassland expansion, and a shift to early horticultural economies throughout the region. Soil development occurred after 3000 cal. BP, and this episode of landform stability may have lasted for over two millennia until being capped by sediment accumulation from historic agriculture. The late Middle Archaic through Terminal Late Archaic data from Crumps Sink demonstrate that hunter-gatherer activities left lasting signatures in soils in Kentucky. The data from the Late Archaic to Terminal Late Archaic periods (ca. 5600-3000 cal. BP) may indicate intentional land burning by hunter-gatherers to create anthropogenic environments, first for silviculture and then for early plant domestication. This forces a rethinking of labor and subsistence systems within hunter-gatherer societies. Thus, if hunter-gatherers were utilizing long-term forest management methods, they were employing a delayed-return economic system relying on labor investment and negotiated understandings about land tenure. Further characterization of the origin of fire management activities will help us to elucidate the nature of incipient indigenous plant domestication in the Eastern Woodlands.

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The mangrove acts as marine nursery, geochemical filter and source of income for the population, however, the degradation and pollution of mangroves may favor the release of toxic substances such as heavy metals. In this sense, this study aimed to analyze the levels of iron (Fe), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), cobalt (Co) and its relationships with the physical and chemical attributes, and to evaluate soil quality through national and international guidelines. They collected three profiles in each of the four areas studied (Bar Mamanguape- PB; estuary of the river Botafogo- B; Canal Santa Cruz-CSC, the Timbó- T River estuary). Samples were collected with samplers for flooded soils and the samples were subjected to hydrogen potential analysis (pH), redox potential (Eh), total organic carbon (TOC), carbonates (CO3-), grain size and by acid digestion method 3051A. The near neutral pH (6.5 to 8.5) and Eh levels in suboxic (Eh 100-350 mV) and anoxic (Eh <100 mV) discloses a geochemical reducing environment. The predominance of fine particles (silt and clay) and organic matter are present in soils around the estuary B and PB1 and PB2 profile, except in the soil CSC estuaries, T and PB3 profile where there was a predominance of sand fraction by situate near mouth. High positive correlations (r> 0.70) were found between fine particles, TOC and metals studied. Environmentally available mercury levels in the estuary B were higher than the ERM (Probable effects level), ERL (Effects range low) TEL (Threshold effect level), PEL (Probable effects level), VP (Value prevention) and the VRQ (quality reference value); Ni exceeded the TEL in some depth in the estuary B profiles, while the soils of other estuaries have levels above the VRQ. Thus, it is possible to identify contamination of Hg and Pb in the B and CSC estuary profiles; Cu B, CSC and PB; Ni B, and CSC PB; and Fe in the estuary B and PB; while for the Co there was no contamination in any of the studied estuaries. The FE (Factor enrichment) and Igeo (Geo-accumulation index) reveal that the B estuary had a severely serious enrichment (EF> 25) and is highly to extremely polluted (Igeo class 5) for Hg, respectively ; and low-enriched (EF <3) to the other metals. The Levels of Hg (Above PEL) and Ni (Above TEL) can be causing toxicity to benthic organisms. From the cluster analysis it was observed that distinctly from the others, Botafogo River estuary is impacted by metals due to strong pressure of human activities on the north coast of Pernambuco region. As a result, mangrove soil into the river Botafogo stands out as one of the marine ecosystem most impacted by Hg.
O manguezal atua como berçário marinho, filtro geoquímico e fonte de renda para a população, porém, a degradação e poluição dos manguezais podem favorecer a liberação de substâncias tóxicas como os metais pesados. Nesse sentido, o presente trabalho objetivou analisar os teores de ferro (Fe), cobre (Cu), chumbo (Pb), mercúrio (Hg), níquel (Ni), cobalto (Co) e suas relações com os atributos físico-químicos, além de avaliar a qualidade dos solos por meio de diretrizes nacionais e internacionais. Foram coletados 3 perfis em cada uma das 4 áreas estudadas (Barra de Mamanguape- PB; Estuário do rio Botafogo- B; Canal Santa Cruz- CSC; Estuário do rio Timbó- T). As coletas foram realizadas com amostradores para solos inundados e as amostras foram submetidas a análises de potencial de hidrogênio (pH), potencial de oxirredução (Eh), carbono orgânico total (COT), carbonatos (CO3-), granulometria e digestão ácida pelo método 3051A. O pH próximo da neutralidade (6,5 e 8,5) e o Eh em níveis subóxicos (Eh 100-350 mV) e anóxicos ( Eh <100 mV) revelam um ambiente geoquímico redutor. O predomínio de partículas finas (silte e argila) e matéria orgânica estão presentes nos solos em todo estuário B e no perfil PB1 e PB2, exceto nos solos dos estuários CSC, T e no perfil PB3 onde houve predominância da fração areia por situarem próximos à desembocadura. Altas correlações positivas (r > 0,70) foram encontradas entre partículas finas, COT e os metais estudados. Os teores de Hg ambientalmente disponíveis no estuário B foram superiores ao ERM (Probable effects level), ERL (Effects range low), TEL (Threshold effect level), PEL (Probable effects level), VP (Valor de prevenção) e o VRQ (Valor de referência de qualidade); o Ni superou o TEL em algumas profundidades nos perfis do estuário B, enquanto nos solos dos demais estuários apresentaram valores superiores ao VRQ. Desta forma, é possível identificar contaminação por Hg e Pb em perfis do estuário B e CSC; por Cu em B, CSC e PB; por Ni em B, CSC e PB; e por Fe no estuário B e PB; enquanto para o Co não houve contaminação em nenhum dos estuários estudados. O FE (Fator de Enriquecimento) e o Igeo (Índice de Geo-acumulação) revelam que o estuário B teve um enriquecimento severamente grave (FE > 25) e encontra-se altamente a extremamente poluído (Igeo classe 5) para o Hg, respectivamente; e baixo enriquecimento (FE < 3) para os demais metais. Os Teores de Hg (Acima do PEL) e Ni (Acima do TEL) podem está causando toxicidade a organismos bentônicos. A partir da análise de agrupamento observou que distintamente dos demais, o estuário do rio Botafogo encontra-se impactado por metais, devido a forte pressão das atividades antrópicas na região do litoral norte pernambucano. Em virtude disso, o solo do manguezal no rio Botafogo se destaca como um dos ecossistemas marinhos mais impactados por Hg.

Increasing sea levels and anthropogenic disturbances have caused the world’s coastal vegetation to decline 25-50% in the past 50 years. Future sea level rise (SLR) rates are expected to increase, further threatening coastal habitats. In combination with SLR, the Everglades ecosystem has undergone large-scale drainage and restoration changing Florida’s coastal vegetation. Everglades National Park (ENP) has 21 coastal plant species threatened by SLR. My dissertation focuses on three aspects of coastal plant community change related to SLR and dehydration. 1) I assessed the extent and direction coastal communities—three harboring rare plant species—shifted from 1978 to 2011. I created a classified vegetation map and compared it to a 1978 map. I hypothesized coastal communities transitioned from less salt- and inundation-tolerant to more salt- and inundation-tolerant communities. I found communities shifted as hypothesized, suggesting the site became saltier and wetter. Additionally, all three communities harboring rare plants shrunk in size. 2) I evaluated invading halophyte (salt-tolerant) plant influence on soil salinity via a replacement series greenhouse experiment. I used two halophytes and two glycophytes (non-salt-tolerant) to look at soil salinity over time under 26 and 38‰ groundwater. I hypothesized that halophytes increase soil salinity as compared to glycophytes through continued transpiration during dry, highly saline periods. My results supported halophytic influence on soil salinity; however, not from higher transpiration rates. Osmotic or ionic stress likely decreased glycophytic biomass resulting in less overall plant transpiration. 3) I assessed the best plant life-stage to use for on-the-ground plot-based community change monitoring. I tested the effects of increasing salinity (0, 5, 15, 30, and 45‰) on seed germination and seedling establishment of five coastal species, and compared my results to salinity effects on one-year olds and adults of the same species. I hypothesized that seedling establishment was the most vulnerable life-stage to salt stress. The results supported my hypothesis; seedling establishment is the life-stage best monitored for community change. Additionally, I determined the federally endangered plant Chromolaena frustrata’s salinity tolerance. The species was sensitive to salinity >5‰ at all developmental stages suggesting C. frustrata is highly threatened by SLR.

Purple-flowered rhododendron (Rhododendron ponticum L.) and yellow-flowered rhododendron (R. flavum Don.) are two dominant shrub species of the eastern beech (Fagus orientalis L.) understories in the eastern and western Black Sea Region (BSR), respectively. These invasive woody species significantly reduce beech growth and can preclude tree regeneration. The ecological consequence is an aging beech overstory with little or no regeneration to replace the mature trees. Great rhododendron (R. maximum L.) has been increasing in the forests of the Southern Appalachians of the United States, reducing tree regeneration and growth. The BSR and Southern Appalachians bear noteworthy similarities in climate, topography, and the forest flora. Purple-flowered and great rhododendrons also show important similarities in their ecology and the forest vegetation problems they can cause. Current rhododendron-dominated and threatened BSR forests may provide an advanced ecological picture of the forests of the Southern Appalachians in which great rhododendron now thrives. Therefore, new information gained on the ecology and effective and cost-efficient control of purple-flowered rhododendron may significantly improve forest management practices, not only for the current rhododendron-invaded BSR ecosystem, but also for other parts of the world. This dissertation consists of five separate yet related chapters. The first gives relevant literature reviewed for the dissertation. The second chapter focuses on various environmental and disturbance factors that may have shaped the current purple-flowered rhododendron-dominated beech forests of the BSR of Turkey. Chapter 3 assesses the effects of various manual and herbicidal woody control techniques on purple-flowered and yellow-flowered rhododendron in two field experiments in the BSR. The fourth chapter relates a study of uptake and translocation behavior of triclopyr ester and imazapyr in great rhododendron. This information is used to determine the optimum herbicide-surfactant combinations for the greatest active ingredient uptake and root translocation in great rhododendron. The last chapter is a synthesis of the information gained in all of these different experiments.
Ph. D.

A Araucaria angustifolia, conhecida como Pinheiro-do-Paraná é uma espécie ameaçada de extinção no Brasil, está inserida num bioma rico em biodiversidade, a Mata Atlântica, e muito pouco se conhece sobre os atributos microbiológicos dessas florestas. Este trabalho teve como objetivo avaliar potenciais atributos microbiológicos do solo e algumas variáveis ambientais (atributos químicos, físicos e efeito sazonal), a fim de estabelecer bioindicadores de qualidade do solo em Florestas de Araucária. Os estudos foram conduzidos em dois parques estaduais localizados em diferentes regiões do Estado de São Paulo, no município de Campos do Jordão (Parque Estadual de Campos do Jordão - PECJ), nos municípios de Apiaí e Iporanga (Parque Estadual Turístico do Alto Ribeira - PETAR) e também no município de Barra do Chapéu. Foram escolhidas três áreas no PETAR: FN floresta nativa de araucária, ND floresta de araucária com distúrbio antropogênico e PL plantio de araucária; e quatro áreas foram selecionadas no PECJ: FN floresta nativa de araucária, ND floresta de araucária com distúrbio antropogênico, PL plantio de araucária e PF plantio de araucária com ocorrência de fogo acidental. Ao acaso, foram selecionadas quinze árvores de araucária por área e sob a copa de cada uma delas foram retiradas amostras na profundidade de 0 a 20 cm, nas épocas seca e de chuva. Foram avaliados os atributos microbiológicos: arilsulfatase (ARIL), fosfatase ácida (FOSF), -glicosidase (GLIC), desidrogenase (DESID), nitrogênio (NBM) e carbono da biomassa microbiana (CBM), Número Mais Provável (NMP) de amonificantes (AMO), nitritadores (NITRI), nitratadores (NITRA) e desnitrificantes (DESN), respiração basal (RESP), respiração induzida por substrato (RIS), quociente metabólico (qCO2) e microbiano (qMIC). Além disso, foram estabelecidos perfis de ácidos graxos ligados a ésteres de fosfolipídios (EL-PLFAs) e o perfil de capacidade de utilização de substratos de carbono (Biolog). Alguns parâmetros químicos foram avaliados (pH, H++Al3+, Al3+, Ca2+, Mg2+, K+, P, S, N, carbono orgânico total e a capacidade de troca catiônica) e físicos (teores de argila, silte e areia). Verificou-se que o PL do PETAR e PF do PECJ foram relacionados aos atributos microbiológicos ARIL, DESN, CBM e qMIC nos dois períodos. A partição da variabilidade revelou que a atividade microbiana foi influenciada mais pelas variáveis físico-quimicas do solo do que pelas áreas e épocas de coleta. Foram identificados perfis de ácidos graxos semelhantes aos aqui obtidos, PETAR e PECJ, em um trabalho anterior no PECJ, o que pode ser indicação de um padrão de EL-PLFA próprio do ecossistema de araucária. Os ácidos graxos 10Me18:0 (actinobactéria), a relação ácido graxo saturado/insaturado (sat/insat), o consumo dos substratos -metil-D-glicosídeo e o ácido 2-hidroxibenzóico foram também relacionados às áreas PL (PETAR) e PF (PECJ) nos períodos avaliados. Já os ácidos graxos 18:19c (fungo) e 16:17c (bactéria Gram-), o consumo dos substratos glicose-1-fosfato, -D-lactose e ácido -hidroxibutírico estavam relacionados às áreas impactadas dos dois parques durante os períodos de seca e chuva. Portanto, esses atributos microbiológicos são potenciais indicadores de qualidade do solo em Florestas de Araucária, no entanto, novas avaliações são necessárias para as devidas validações dos bioindicadores e monitoramento dessas áreas.
Araucaria angustifolia, also called Brazil Pine, is an endangered species in Brazil. It is part of one of the richest ecosystems in biodiversity, the Atlantic Forest, and little is known about the soil microbiological attributes in this forest. The objective was to evaluate the potential of the soil microbiological attributes and some environmental variables (physical-chemical properties and seasonal effect) to act as bioindicators of soil quality in Araucaria Forests. This study was undertaken in two different state parks in the São Paulo State, in Campos do Jordão county (Campos do Jordão State Park - PECJ), and in Apiaí and Iporanga counties (Alto Ribeira Touristic State Park - PETAR) and also in Barra do Chapéu county. Three areas were surveyed in PETAR: FN Native Araucaria forest, ND Native Araucaria forest with anthropogenic disturbance, and PL Reforested Araucaria; and four areas in PECJ: FN Native Araucaria forest, ND Native Araucaria forest with anthropogenic disturbance; PL Reforested Araucaria, and PF Araucaria reforestation submitted to an accidental fire. Fifteen Araucaria trees were selected at random in each area and the soil and roots were sampled at 0 20 cm depth, in two contrasting seasons (dry and wet). The microbiological attributes evaluated were: arylsulfatase (ARIL), acid phosphatase (FOSF), -glucosidase (GLIC), dehydrogenase (DESID), carbon (CBM) and nitrogen microbial biomass (NBM), most probable number (NMP) of bacterial ammonium oxidizers (AMO), nitrite oxidizers (NITRI), nitrate oxidizers (NITRA) and denitrifiers (DESN), basal microbial respiration (RESP), substrate induced respiration (RIS), and metabolic (qCO2) and microbial quotient (qMIC). Additionally we determined the phospholipid fatty acid profiles (ELPLFA) and the community level physiological profile (Biolog). Some chemical attributes were evaluated (pH, H++Al3+, Al3+, Ca2+, Mg2+, K+, P, S, CEC, C/N ratio, total organic carbon (COT), total nitrogen (NT), as well as some physical ones (soil texture: clay, sand and silt contents). There was a high correlation between the PL of PETAR and the PF of PECJ and the microbiological attributes ARIL, DESN, CBM and qMIC in both periods. The partitioning of the variability evidenced that microbial activity was influenced in a higher degree by the physical-chemical properties of soil than by study areas or periods. We identified similar fatty acid profiles in PETAR and PECJ and they were also similar to the ones found in a previous work in PECJ, what could indicate a specific EL-PLFA pattern in the Araucaria ecosystem. The fatty acids 10Me18:0 (actinobacteria), the saturated/unsaturated fatty acid ratio (sat/insat), the substrate utilization of -methyl-D-glucoside and 2-hydroxybenzoic acid were also related to PL (PETAR) and PF (PECJ), in both periods. The 18:19c fatty acid (fungi) and 16:17c (Gram-), the glucose-1-phosphate, -D-lactose and -hydroxybutyric acid were C-source for microbial communities of the impacted areas in both parks during the wet and dry periods. Therefore, these attributes are potential microbial indicators of soil quality in Araucaria forests, however, new evaluations are required to confirm these biomarkers and to monitor these areas.

En Europe, l'augmentation des températures moyennes de surface de l'air projetée au cours du 21ème siècle s'accompagne d'une augmentation des extrêmes chauds et d'une diminution des extrêmes froids. Dans les dernières décennies, des indices témoignent déjà de ces changements, comme l'établissement récurrent de nouveaux records de chaleur ou l'augmentation des canicules. Nous étudions l'évolution des extrêmes journaliers de température au cours du 20ème et du 21ème siècle en France et en Europe, et ce en termes d'occurrence et d'intensité. Un intérêt particulier est aussi porté aux mécanismes responsables de ces futurs extrêmes climatiques, ainsi qu'aux futures températures maximales. Nous nous intéressons tout d'abord à l'évolution des records journaliers de température à partir d'observations et de modèles de climat. Entre 1950 et 1980, l'évolution théorique des records dans le cadre d'un climat stationnaire représente correctement l'évolution observée des records chauds et froids. Depuis les années 1980, un écart à ce climat stationnaire est observé, avec respectivement une augmentation et une diminution de l'occurrence des records chauds et froids. Les modèles climatiques suggèrent une accentuation de ces changements au cours du siècle. L'occurrence moyenne des records chauds à la fin du siècle présente une forte augmentation par rapport aux premières décennies de la période observée. L'augmentation la plus importante des records chauds est projetée en été, en particulier dans la région méditerranéenne. Quant aux records froids, les modèles indiquent une diminution très importante de leur occurrence, avec une occurrence quasi-nulle dans les dernières décennies. Les variations observées d'occurrence de records sont, au début du 21ème siècle, toujours dans l'éventail des fluctuations de la variabilité interne du climat. Au cours du siècle, l'émergence de l'influence anthropique de ces fluctuations est détectable dans l'évolution des records chauds et froids en été, et ce respectivement autour des décennies 2030 et 2020. À l'horizon de la fin du siècle, les changements moyens d'occurrence de records ne peuvent pas être uniquement expliqués par des fluctuations naturelles. Nous nous sommes ensuite intéressés aux futures températures estivales extrêmes, ainsi qu'aux canicules intenses qui peuvent être à l'origine de ces extrêmes. Pour cela, l'utilisation de modèles climatiques globaux est associée à la modélisation climatique régionale et à des stations d'observations en France. Tout d'abord, l'augmentation maximale des valeurs maximales des records journaliers de température en été en France est estimée à partir d'une simulation régionale à haute résolution spatiale. À l'horizon 2100, les projections indiquent une augmentation maximale de ces valeurs extrêmes en été comprise entre de 6.6°C et 9.9°C selon les régions de la France. La comparaison de ces projections avec un ensemble de modèles climatiques indique que ces augmentations maximales pourraient être plus importantes. La médiane de la distribution des modèles indique en effet une augmentation maximale de ces valeurs maximales des records journaliers de température de 11.8°C en été et en France. Puis, des expériences de modélisation de canicules intenses du climat européen de la fin du 21ème siècle ont été réalisées à partir d'événements particuliers d'un modèle de climat. Ces expériences ont mis en évidence le rôle des interactions entre le sol et l'atmosphère dans l'amplification des températures extrêmes lors de futurs évènements caniculaire intenses. L'occurrence de telles canicules est d'abord dépendante de la circulation atmosphérique, mais l'intensité des températures peut ensuite être fortement amplifiée en fonction du contenu en humidité des sols avant la canicule, et donc des conditions climatiques des semaines et des mois précédents
Over the 21st century, the mean increase in surface air temperatures is projected to be associated with an increase in warm temperature extremes and a decrease in the cold ones. Over the last decades, evidence already suggests these changes, as for example recurrent warm record-breaking temperatures or the increase in heatwave occurrence. We investigate the evolution of daily temperature extremes over the 20th and the 21st centuries in France and in Europe, their possible changes in frequency and intensity. We also focus on the mechanisms responsible for these projected climate extremes, as well as the maximum values of temperature extremes at the end of the century. First, we investigate the evolution of daily record-breaking temperatures in Europe based on the observations and an ensemble of climate models. From the 1950s to the 1980s, the theoretical evolution of the records in a stationary climate correctly reproduce the observed one, for both cold and warm records. From 1980, a shift from that theoretical evolution is observed, with an increase in the occurrence of warm records and a decrease in the occurrence of the cold ones. Climate models suggest an amplification of these changes over the century. At the end of the 21st century, the mean number of warm records shows a strong increase compared to the first decades of the observed period. The strongest increase in warm record-breaking temperatures is found in summer, and particularly over the Mediterranean edge. On the contrary, the occurrence of cold record-breaking temperatures is projected to strongly decrease, with almost no new records in the last decades of the century, for all seasons and over the entire European domain. Observed variations of daily record-breaking temperatures are still, at the beginning of the 21st century, consistent with internal climate variability only. Over the century, the anthropogenic influence emerge from these fluctuations in the summer record evolutions, around the 2030 and the 2020 for the warm and cold records respectively. By 2100, the mean changes in record occurrences cannot be explained by the internal climate variability solely, for all seasons and over the entire European domain. Then, we investigate future extreme temperatures at the end of the 21st century, as well as severe heatwaves leading to these extremes. Climate models analyses are associated with regional climate modeling and a French station-based dataset of observations. The summer 21st century evolution of the maximum values of daily warm record-breaking temperatures is first examined in the observations and the high resolution simulation of the regional model. By 2100, an increase of these values is projected, with maximum changes between +6.6°C and +9.9°C in summer among the French regions. These projections assessed from a regional model may underestimate the changes. The multi-model mean estimate of the maximum increase of these values is indeed around +11.8°C in summer over France. Finally, regional modeling experiments of severe heatwaves in the climate of the end of the 21st century in Europe are performed. These severe heatwaves are selected cases from a global climate model trajectory. The experiments results show the role of the soil-atmosphere interactions in the amplification of the extreme temperatures during such future severe warm events. The occurrence of the heatwave is first caused by the atmospheric circulation, but the temperature anomaly can then be amplified according to the soil moisture content before the event, and thus the climatic conditions of the preceding weeks and months

Mon sujet de thèse intègre l’un des projets globaux de l’UMR UFC/CNRS 6249 Chrono-Environnement intitule « stratégies de phytoremédiation basées sur l’utilisation d’arbres et de microorganismes associés », qui s’appuie, entre autre, sur 2 projets de recherche :• le projet PROLIPHYT (programme Eco-Industrie, 2013-2018, ADEME) intitulé « PROduction de LIgneux PHYtoremédiants»,• le projet PHYTOCHEM (ANR CD2i, 2013-2018) intitulé « Développement de procédés chimiques éco-innovants pour valoriser les biomasses issues des phytotechnologies ».Les objectifs généraux sont d’améliorer le potentiel de phytoremédiation d’un panel d’espèces ligneuses et de développer le potentiel microbien pour une phytoremédiation aidée sur sol contaminé. En plus de limiter l’impact des polluants, cette stratégie vise à promouvoir la production de biomasse sur sols délaissés et non exploitables par l’agriculture, tout en assurant la biodiversité nécessaire à la restauration d’un écosystème anthropogénique.Mon travail de thèse est financé au travers un contrat doctoral ministériel handicap (dyslexie). Il s’appuie sur la réhabilitation de deux zones de stockage de sédiments industriels, utilisés jusque dans les années 2000. Ces deux sites expérimentaux (site INOVYN de St Symphorien-sur-Saône en Côte d’Or, site CRISTAL de l’Ochsenfeld en Alsace) présentent des caractéristiques physico-chimiques très particulières qui en font des lieux d’étude privilégiés. Le premier est une ancienne lagune de décantation dont les sédiments enrichis en Hg, Ba et As proviennent du traitement des eaux usées issues du procédé d’électrolyse à Hg de l’entreprise SOLVAY. Le second est une lagune constituée d’un remblai dans lequel ont été stockés depuis les années 1930, les résidus d’extraction du dioxyde de titane de l’Usine CRISTAL de Thann. A l’inverse du premier site expérimental, on observe une flore peu abondante qui se traduit par un développement hétérogène d’une espèce ligneuse principale, le bouleau.La recolonisation naturelle et spontanée de végétaux, plus particulièrement d’espèces ligneuses sur les deux sites est sans doute le résultat d’étroites collaborations avec des microorganismes telluriques situés aux abords de leur système racinaire. Nous avons ainsi choisi de travailler sur 3 espèces pionnières qui se sont naturellement réimplantées sur les deux sites d’études : le saule et le peuplier pour la friche industrielle de Tavaux et le bouleau pour l’unité de traitement des effluents du site de l’Ochsenfeld
AbstractMy thesis subject includes one of the global projects of the UMR UFC/CNRS 6249 Chrono-Environnement entitled "phytoremediation strategies based on the use of trees and associated microorganisms", which is based, among other things, on 2 research projects:• the PROLIPHYT project (Eco-Industry programme, 2013-2018, ADEME) entitled "Production of woody phytoremediants",• the PHYTOCHEM project (ANR CD2i, 2013-2018) entitled "Development of eco-innovative chemical processes to exploit biomasses from phytotechnologies".The general objectives are to improve the phytoremediation potential of a panel of woody species and to develop the microbial potential for assisted phytoremediation on contaminated soil. In addition to limiting the impact of pollutants, this strategy aims to promote the production of biomass on land abandoned and not exploitable by agriculture, while ensuring the biodiversity needed to restore an anthropogenic ecosystem.My thesis work is financed through a ministerial doctoral contract for disability (dyslexia). It is based on the rehabilitation of two industrial sediment storage areas, used until the 2000s. These two experimental sites (INOVYN site of Saint-Symphorien-sur-Saône in Côte-d'Or, CRISTAL site of Ochsenfeld in Alsace) present very particular physico-chemical characteristics which make them privileged places of study. The first is a former settling lagoon whose sediments enriched in Hg, Ba and As come from the treatment of wastewater from SOLVAY's Hg electrolysis process. The second is a lagoon consisting of a backfill in which the titanium dioxide extraction residues from the CRISTAL Thann Plant have been stored since the 1930s. In contrast to the first experimental site, there is a low abundance of flora which results in heterogeneous development of a main woody species, the birch.The natural and spontaneous recolonisation of plants, more particularly woody species on both sites, is undoubtedly the result of close collaboration with telluric microorganisms located near their root systems. We have thus chosen to work on 3 pioneer species that have naturally relocated to the two study sites: willow and poplar for the industrial wasteland of Tavaux and birch for the effluent treatment unit at the Ochsenfeld site

Magnetic susceptibility has been used as an effective tool for affordable, rapid, and highly sensitive measurements that provide information about the compositional changes of mineral materials in rocks and soils. It has been demonstrated that a relationship between heavy metal concentrations, pollution, and magnetic susceptibility exists. The objective of this study is to use magnetic susceptibility as a method for the detection of the anthropogenic impact on the environment within Baton Rouge, Louisiana. Based on preliminary results from a previous study, we investigated a 100 square mile area, covering a variety of environmental settings, including urban areas and industrialized parts of the inner city. At each site, 20 magnetic susceptibility readings were taken and discrete surface and subsurface samples were collected for subsequent laboratory analysis.

Contour maps and histograms of magnetic susceptibility values indicate a close correlation between environmental setting and the intensity of magnetic susceptibility. Magnetic susceptibly increases within urban and industrialized areas compared to rural areas within the area of investigation. Enhanced susceptibility was observed in the industrialized areas in all magnetic parameters, including susceptibility maps of field measurements, discrete samples, and isothermal remanent magnetization. The field susceptibility data display a stronger correlation compared to the discrete sample analysis because of the statistically significant amount of data collected at each site. There is no apparent correlation between magnetic susceptibility and lithology/soil type in this area. Acquisition curves of the isothermal remnant magnetization indicate the presence of both high- and low coercivity minerals, probably magnetite with a small amount of hematite or goethite as the carriers of magnetic remanence.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Pesquisas ambientais referentes à relação da sociedade com a natureza em tempos pretéritos mostram a relevância do estudo interdisciplinar entre a Geografia e a Arqueologia. Nesse sentido, foi realizado um estudo do Sítio Arqueológico Piracanjuba, localizado no Município de Piraju, SP, na região do Médio Rio Paranapanema, pelo viés teórico da Arqueologia da Paisagem. Trata-se de um sítio litocerâmico Guarani, cuja área é estudada visando compreender o padrão de assentamento para, depois, submetê-lo ao exame comparativo com os demais sítios arqueológicos Guarani do Médio Paranapanema. O ambiente foi analisado, segundo os pressupostos geossistêmicos horizontais (geofácies e geótopo) e verticais (geohorizontes), a fim de abordar a representação e espacialização cartográfica do sítio em sua relação com as características do complexo físico-geográfico da área. Para a sistematização dos dados, foram utilizados programas de Sistema de Informação Geográfica (SIG), como o QGIS, bem como programa de desenho assistido, como o AutoCad e CorelDRAW, além da análise de fotografias panorâmicas, fotografias aéreas (estereoscopia analógical) e imagens de satélite. Os resultados desta dissertação contribuem para o trabalho de análise da paisagem em pesquisas arqueológicas, sobretudo no que diz respeito ao Sistema de Ocupação Regional Guarani no Vale do Rio Paranapanema, além da discussão sobre Arqueologia da Paisagem pelo viés geossistêmico.
Research concerning the relationship between society and the environment in past times shows the relevance of interdisciplinary studies between Geography and Archeology. In this sense, a study of the Piracanjuba Archaeological Site, located in the Municipality of Piraju, SP, in the region of the Middle Paranapanema River, was carried out by the theoretical bias of Landscape Archeology. It is a Guarani litho-ceramic site. The area of the site is studied in order to understand the pattern of settlement and then submit it to the comparative examination with the other Guarani archaeological sites of the Middle Paranapanema. The environment was analyzed according to geosciences (geo-geology and geo-geology) and vertical (geohorizon) assumptions in order to approach the representation and mapping of the site in its relation with the characteristics of the physical-geographic complex of the area. For the systematization of the data, Geographic Information System (GIS) programs such as QGIS were used, as well as an assisted design program such as AutoCad and CorelDRAW, as well as the analysis of panoramic photographs, aerial photographs (digital stereoscopy) and satellite images. The results of this dissertation contribute to the work of analyzing the landscape in archaeological research, especially with regard to the Guarani Regional Occupation System in the Paranapanema River Valley, besides the discussion on Landscape Archeology by the geosystemic bias.
Las investigaciones referentes a la relación de la sociedad con el ambiente en tiempos pretéritos muestran la relevancia de estudios interdisciplinarios entre la Geografía y la Arqueología. En ese sentido, se realizó un estudio del Sitio Arqueológico Piracanjuba, ubicado en el Municipio de Piraju, SP, en la región del Medio Río Paranapanema, por el sesgo teórico de la Arqueología del Paisaje. Se trata de un sitio lítico de Guarani. El área del sitio es estudiada para comprender el patrón de asentamiento para luego someterlo al examen comparativo con los demás sitios arqueológicos Guaraní del Medio Paranapanema. El ambiente fue analizado, según los supuestos geosistémicos horizontales (geofácies y geótopo) y verticales (geohorizontes), a fin de abordar la representación y espacialización cartográfica del sitio en su relación con las características del complejo físico-geográfico del área. Para la sistematización de los datos, se utilizaron programas de Sistema de Información Geográfica (SIG) como QGIS, así como programa de diseño asistido como AutoCad y CorelDRAW, además del análisis de fotografías panorámicas, fotografías aéreas (estereoscopia digital) e imágenes de satélite. Los resultados de esta disertación contribuyen al trabajo de análisis del paisaje en investigaciones arqueológicas, sobre todo en lo que se refiere al Sistema de Ocupación Regional Guaraní en el Valle del Río Paranapanema, además de la discusión sobre Arqueología del Paisaje por el sesgo geosistémico.
134389/2016-6

Global environmental concerns arise when marine deposits with fine-grained iron sulfide-rich sediments (FeS and FeS2), now situated above sea level, oxidize from anthropogenic lowering of the groundwater table. The oxidation of iron sulfides decreases the soil pH and the acidic environment of these Acid Sulfate Soils (AS) soils increase weathering and mobilization of metals into adjacent watercourses, lakes and estuaries. Low pH and enhanced concentrations of metals are known to influence water quality negatively, causing fish kills and reduced aquatic diversity. Sulfide rich sediments were deposited in the Baltic Sea after the last glaciation and are now abundantly found along the coasts of for example the Bothnian Bay as a result of isostatic rebound. Recent studies from Finland have stated associations between leached (AS) soils and increased concentrations of metals in estuary sediments, thus the effects are likely to be similar in Sweden. With financial support from the Interreg Nord project “Ecological restoration in coastal river basins in the Bothnian Bay” in cooperation with the Geological Survey of Sweden (SGU), sediments from three lakes and two estuarine sites in the Rosån catchment in Norrbotten county, northern Sweden, were sampled and analyzed with fpXRF, ICP-MS and LOI methods. Elemental concentrations and organic contents were compared to establish accumulation trends over time and relationships between metal concentrations in recently deposited sediments and potential influence from previously sampled (AS) soils. Correlations in time, to anthropogenic activity, such as ditching were also considered. A primary allover trend with increasing concentrations of Aluminum (Al), Arsenic (As), Cadmium (Cd), Cobalt (Co), Cupper (Cu), Iron (Fe), Manganese (Mn), Nickel (Ni), Lead (Pb), Rare Earth Elements (REE) and Zinc (Zn), was noticed in a majority of the lake and estuary sediment samples. With some site variation, also two discrete peaks at different depth, were found in the upper 20 to 30 cm of the sampled sediments. Significant correlations to organic matter were also found for a considerable amount of the elements. Soil samples from (AS) soils in areas related to Rosån show pH values as low as 2.62 and oxidation depths down to 170 cm. Substantial elemental depletion in the oxidized zone suggest increased weathering, leaching and mobilization of Al, Cd, Co, Mn, Ni, REE, Zn and to some extent As, Cu, Fe and Pb from the soil, as a consequence of the acidic environment. A relationship between (AS) soils and increased metal concentrations is therefore likely. The sedimentation rate of roughly 0.2 cm/year was calculated from the separation age of the lakes and the sediment depth to an interpreted transition from more marine environment to lake settings. Consequently the distinct peaks of increased metal concentrations are thus suggested to be related to anthropogenic activities as for example improved drainage methods after the Second World War, but proper dating of the sediments is needed to establish any certain correlations.
På senare tid har man uppmärksammat de miljöproblem som uppstår när finkorniga sediment, innehållande järnsulfider, oxiderar på grund av mänsklig påverkan, t ex. dikning, eller annan typ av aktivitet som sänker grundvattennivån. När järnsulfiderna oxiderar bildas svavelsyra som gör att pH- värdet i marken blir väldigt lågt. Den sura miljön i dessa så kallade sura sulfatjordar, gör i sin tur att mineraler i marken vittrar fortare med påföljden att både surt vatten och ökade mängder metaller, sprids till närliggande vattendrag, sjöar och hav. Lågt pH och höga halter av metaller i vatten påverkar även vattenkvalitén negativt och har rapporterats orsaka fiskdöd och minskad akvatisk mångfald. Sura sulfatjordar är globalt förekommande och återfinns bland annat längs Bottenvikens kuster. De har kunnat bildas genom att sulfidhaltiga sediment, som avsattes i Östersjön efter den senaste istiden, nu befinner sig ovan havsnivån på grund av landhöjningen. I Finland har man i flera studier sett ett samband mellan sura sulfatjordar och ökade metallhalter i nyligen avsatta kustsediment och man kan anta att liknande förhållande gäller även i Sverige. Med finansiellt stöd från EU-projektet “Kustmynnande Vattendrag i Bottenviken-Metodutveckling och Ekologisk Restaurering” (Interreg Nord) genom Sveriges geologiska undersökning (SGU) och i samarbete med Länsstyrelsen i Norrbotten, har bottensediment från tre sjöar och två fjärdar i Rosåns avrinningsområde i Norrbotten provtagits och analyserats. För att fastställa hur koncentrationerna har förändrats över tiden har metallhalterna i de nyligen avsatta sedimenten jämförts med koncentrationerna i äldre sediment. Även jordprofiler från sura sulfatjordar i området har studerats för att kunna utvärdera ett ev. samband mellan urlakade ämnen i jordarna och ökade halter i sedimenten. Granskning av hur långt metallerna transporteras i systemet har gjorts, liksom försök att hitta kopplingar i tiden till mänsklig påverkan som t.ex. dikning. I de översta sedimenten kan man, förutom en generellt ökande trend av aluminium (Al), arsenik (As), kadmium (Cd), kobolt (Co), koppar (Cu), järn (Fe), mangan (Mn), nickel, (Ni) bly (Pb), sällsynta jordartsmetaller (REE) och zink (Zn), också se tydliga toppar med ökade halter av dessa ämnen på minst två specifika djup. De sura sulfatjordarna, som uppmätte pH-värden ner till 2,62, visade tecken på urlakning av Al, Cd, Co, Ni, Mn, REE, Zn och till viss del också As, Cu, Fe och Pb, varpå en trolig relation mellan sura sulfatjordar och ökade metallhalter i nyligen avsatta sediment kan fastställas. En uppskattning av ackumulationshastigheten, som gjordes utifrån när de provtagna sjöarna skiljdes från havet, och sedimentdjupet som visar övergången från hav till sjö, visar att de observerade topparna av ökade metallkoncentrationer i sedimenten skulle kunna vara förknippade med dikning i början av 1900-talet och efter andra världskriget. För en säker bestämning av sambandet till specifika händelser behövs dock en riktig datering.

The Sámi’s past activities have been documented historically from a European perspective, and more recently from an anthropological viewpoint, giving a generalised observation of the Sámi, during the study period of AD200-AD1800, as semi-nomadic hunter gatherers, with several theories suggesting that interaction with Europeans, through trade, led to the adoption of European activities by certain groups of the Sámi (Eiermann, 1923; Paine, 1957; Manker and Vorren, 1962; Bratrein, 1981; Mathiesen et al, 1981; Meriot, 1984). However, there is almost no information on the impact the Sámi had on the landscape, either before or after any adoption of European activities, and none investigating what cultural footprint or indicators would remain from Sámi or European occupation and/or activity within the typically podzolic soils of Northern Sweden. Consequently the thesis aims to contribute to the gap in knowledge through the formation of a podzol model identifying the links between anthropogenic activity and the alteration of podzol soils, and through the creation of soils based models which identify the cultural indicators associated with both Sámi and European activity; formed from the identification of cultural indicators retained within known Sámi and European sites. The methods used to obtain the information needed to achieve this were the pH and magnetic susceptibility from bulk soil samples and micromorphological and chemical analysis of thin section slides through the use of standard microscopy and X-ray fluorescence from a scanning electron microscope. The analysis revealed that the Sámi had an extremely low impact on the landscape, leaving hard to detect cultural indicators related to reindeer herding in the form of reindeer faecal material with corresponding phosphorous peaks in the thin section slides. The European footprint however, was markedly different and very visible even within the acidic soil environment. The European indicators were cultivation based and included phosphorous and aluminium peaks as well as a deepened, highly homogenised plaggen style anthropogenic topsoil rich in ‘added’ materials. An abandoned European site which visibly and chemically shows the formation of a secondary albic horizon within the anthropogenic topsoil also provides an insight into the delicate balance of cultivated soil in northern Sweden, whilst reinforcing the outputs identified in the podzol model. Due to the almost invisible Sámi footprint on the landscape, areas of overlap were impossible to identify however, there was no evidence of the adoption of European cultivation activities at any of the Sámi sites investigated. The only known area of interaction between the two cultures was an official market place which had been a Sámi winter settlement prior to its use as a market site. This site showed none of the reindeer based Sámi indicators or the cultivation based European indicators, but did contain pottery fragments which could be linked to trade or occupation. Overall, the thesis reinforces the low impact expected of the semi-nomadic Sámi and sheds light on the underlying podzolic processes influencing the anthropogenically modified soils of Northern Sweden. The podzol model is reinforced by several findings throughout the thesis and the soils based cultural indicator models for both Sámi and European activity have been successfully tested against independent entomological and palynological data and therefore provide reliable reference material for future studies.

La diversite biologique du cercle d'anzi est apprehendee sous trois formes etroitement liees: specifique, pedologique et genetique. La premiere partie approfondit nos connaissances sur le climat et tente une estimation de l'evolution de l'arganeraie au cours des trente dernieres annees. Sont aussi developpees une analyse frequentielle et une etude chronologique de longues series de precipitations. La deuxieme partie presente la carte de la vegetation spontanee et montre l'impact de l'homme sur l'environnement. Quatre communautes vegetales correspondant a de nombreuses sous-associations et facies sont decrites et leurs exigences ecologiques precisees. La troisieme partie presente la zonation bioclimatique des sols, tous caracterises par un appauvrissement de leur horizon de surface et une importante argilisation. A l'inframediterraneen, les sols sont brun-rouge subarides et rouges fersiallitiques appauvris et satures; au thermomediterraneen le sol climacique est un sol fersiallitique generalement desature et tres appauvri. La quatrieme partie traduit la microevolution chez l'arganier en mesurant le niveau de polymorphisme des feuilles et en determinant son regime de reproduction. La variation est plus grande a l'interieur de chaque population qu'entre populations elles-memes et l'analyse des descendances conforme que l'arganier est bien allogame dans de grandes proportions

Les alpages laitiers des alpes du nord externes (france) representent un type de systeme ecologique original refletant les effets des pratiques d'eleveurs (fertilisation, paturage) combines aux contraintes du milieu montagnard (etage subalpin). Face aux mutations recentes des modes d'exploitation des alpages, des recherches ont ete engagees pour comprendre et prevoir l'impact des pratiques pastorales sur la dynamique de ces pelouses d'altitude. Nous proposons un modele d'evolution de la composition botanique qui integre l'effet des facteurs anthropiques et celui des facteurs edaphiques. Ce modele s'appuie sur une analyse factorielle des correspondances portant sur un echantillonnage de six cent releves floristiques couvrant l'ensemble de la zone d'etude. La reconstitution des trajectoires dynamiques se fait principalement par une approche synchronique, completee par des observations diachroniques qui ont permis de preciser les vitesses d'evolution de la vegetation. L'essentiel des travaux porte sur des situations de deprise: la dynamique de la vegetation y reflete une degradation de la fertilite des sols consecutive a l'abandon ou a l'allegement de la fertilisation. Cette evolution est generalement lente: deux a cinq decennies sont necessaires pour que l'on enregistre des changements notables dans la composition botanique. Les resultats mettent egalement en evidence l'influence des parametres edaphiques sur les limites et le deroulement de ces successions. Les modalites d'evolution de la vegetation et la hierarchie des facteurs sont precisees dans des trajectoires-types qui permettent d'adapter localement la demarche de diagnostic ecologique. Differents indicateurs, relatifs aux processus physiologiques ou demographiques d'evolution de la vegetation, sont testes afin de preciser ou d'anticiper le diagnostic floristique. Les indices de diversite specifique ou factorielle restent d'un usage delicat en raison de leur sensibilite a l'egard des methodes d'echantillonnage et d'observation. Les indices de nutrition minerale font rapidement apparaitre les modifications d'equilibres trophiques qui suivent l'arret ou la reprise de la fertilisation