Search

ἀe purpose of this study was to analyze the trend of climate change through changes in the elements of Green House Gases (GHGs), includes the trend of CO2, N2O, and CH4. ἀe change of the extreme rainfall and temperature indices due to land cover change into developed area in Padang. IdentiḀcation and analysis trends of climate change and extreme climatic events were analyzed by using RclimDex the Expert Team for Climate Change Detection and Indices (ETCCDMI) technique. Where as the analysis and interpretation of land cover changes into developed area used Landsat TM 5 and Landsat 1985 7 ETM + of 2011 by ERDAS 9.2 GIS with the supervised classiḀcation method and GIS Matrix. ἀe results of the study provide informations of land cover changes into developed area at forest land (11,758.9 ha), shrub (3,337.3 ha), rice Ḁelds (5,977.1 ha), and garden (5,872.4 ha). It has an implication on increasing of the ele-ments of GHGs concentration such as CO2 (14,1 ppm), N2O (5,4 ppb) and CH4 (24,8 ppb). ἀis condition lead to an extreme temperature and presipitation indexs trends in Padang.

This study evaluated changes in land cover in the Chemoga watershed, headwater to the Blue Nile. Two sets of aerial photographs (1957 and 1982) and a multispectral Spot image (1998) were used as inputs to produce 3 GIS-based land cover maps of the area. The results show that during the last 41 years, forest cover increased at a rate of about 11 ha per annum in the 36,400-ha watershed. Woodlands and shrublands decreased between 1957 and 1982 but increased between 1982 and 1998, approximately to their previous levels. Farmland and settled areas gained from the other cover types (13% increase) in the first period but lost around 586 ha (2% decrease) in the second. Grassland and degraded land decreased, accounting for 4.8% of the total area of the watershed in 1982 and 3.5% in 1998, as against 9.6% in 1957. Riverine trees suffered the greatest destruction, shrinking by 79% over the 4 decades; much of this decline was due to cultivation. Marshlands increased in the first period and decreased in the se...

Zachodzące zmiany klimatyczne oraz antropogeniczne przemiany pokrycia terenu powodujące wzrost uszczelnienia zlewni przyczyniają się do zwiększenia się liczby powodzi przyjmujących formę flash floods, tj. powodzi błyskawicznych. Ma to swoje odzwierciedlenie w niekorzystnych skutkach ekonomicznych i społecznych. Celem artykułu jest próba usystematyzowania i uogólnienia wiedzy na temat przyczyn i przebiegu powodzi błyskawicznych. Powódź błyskawiczna jest to nagłe zalanie terenu, charakteryzujące się krótkim czasem trwania oraz lokalnym zasięgiem. Do głównych bezpośrednich przyczyn powodzi błyskawicznych należą: deszcz nawalny, intensywne topnienie pokrywy śnieżnej lub lodu lodowcowego, uszkodzenie lub zniszczenie zapory, grobli lub innej budowli piętrzącej, przerwanie wałów powodziowych, nagłe uwolnienie wód z e zbiornika wodnego lub podniesienie się w nim stanu wody, podtopienie terenu. Powodzie błyskawiczne należą do najkrótszych i najbardziej dynamicznych zdarzeń hydrologicznych. Czas koncentracji i czas trwania fali wezbraniowej podczas powodzi błyskawicznej jest bardzo krótki. W wielu przypadkach powodziom tym towarzyszą intensywne ruchy masowe. Climate change and land cover contribute to the increasing threat of flash floods. They are the shortest and most dynamic hydrological events. Flood disaster is reflected in various significant economic and social losses, especially in the urbanized areas. The main aim of the paper is an attempt to systematize and generalize knowledge about the causes and dynamic of flash floods. The main direct causes of flash floods are very heavy localized rainfall, intense melting of snow cover or glacier ice, damage or destruction of a dam, dike or other structure in the riverbed, the break of flood embankments, the sudden release of water from the lake (e.g.jőkulhalup), sudden increase of water level in lake (e.g. caused by landslide), flooding the area by collected rainwater on nonpermeable area. Flash floods occurs mostly with in 6 hours of a heavy rain event. Time of concentration and duration of the flash flood is very short (varies from a few to several hours). Big rate of load sediment and intense mass movements are accompanying to flash floods.

The Borana rangelands in southern Ethiopia are facing deterioration caused by intensification of grazing and woody plant encroachment, resulting in marked reductions in pastoral production. This process affects the food security and livelihoods of the Borana pastoral people negatively. Woody plant encroachment might result in an increase in carbon (C) storage in these rangelands, which represents an important aspect for climate change mitigation potentials. However, it is unclear how much C is currently stored in the above-and belowground vegetation biomass and in the soils of these rangeland ecosystems and how grazing intensity and woody cover influence soil or ecosystem C-stocks. The research work presented in this thesis aimed at developing tools to estimate the aboveground woody biomass C stocks. It describes the structure of semiarid savanna vegetation in different grazing regimes at various levels of woody encroachment, examines changes in woody plant encroachment, and provides field-based quantification methods and tools to derive site-based estimates of above- and belowground C pools. The thesis also aimed at assessing the influence of grazing on herbaceous above- and belowground biomass C stocks, soil organic carbon (SOC) and total soil nitrogen (TSN) to estimate possible increases in ecosystem C stocks by long term reduction of grazing intensity (e.g., low livestock density and seasonal grazing) at various levels of woody plant encroachment. A long-term temporal satellite imagery over the last 37 years and GIS mapping aided by ground truthing was used to investigate vegetation cover changes. In the field, data was collected to analyze vegetation attributes such as composition and structure under different grazing regimes and woody encroachment sites. Herbaceous species were destructively harvested to quantify the biomass and C stocks in the herbaceous vegetation community. Allometric tree biomass models were developed by destructively harvesting eight woody species to indirectly quantify the woody biomass and C stocks. Total soil nitrogen and SOC stocks in the different grazing management systems and woody encroachment levels were assessed from soil cores collected within 0- 40 cm soil depth. The performance of allometric biomass models as expressed as a goodness of fit (adj r2) depended on the species and biomass components estimated. The allometric models were highly accurate for large woody species such as A. mellifera, A. bussei, and A. etabaica. The most important single models predictor variable identified was stem basal circumference for tall shrubs with more or less open canopy structure. Meanwhile, for tall shrubs with closed and umbrella-like canopy structures, pairs of canopy volume and stem basal circumferences were more reliable predictors. It was further shown that, by using canopy volume as a standalone predictor variable, biomass can still be accurately predicted for shrubs whose growth form comprise discrete canopy clumps with multiple stems (e.g., A. oerfota). Vegetation cover analysis using temporal Landsat imageries from 1976 to 2012 revealed that areas covered by shrub and tree savanna (open savanna types) in the 1970s declined from 45% to 9%, while heavily encroached areas (bushland thickets and bushed savanna) increased from 22% to 61% during this time interval. The abundance of total and the regenerative woody plants (< 1 m height) were high in lower woody encroachment sites but significantly reduced at heavily woody encroachment sites. At all levels of woody encroachment enclosures significantly increased total woody plant density, especially the proportion of woody plants in < 1 m height size class compared to the open rangelands. Estimated total aboveground biomass C stocks varied significantly between woody encroachments levels, with total aboveground biomass C stocks ranging from 2 Mg ha-1 in the low encroachment site to 9 Mg ha-1 in heavy encroachment sites. Enclosures significantly raised the herbaceous biomass C stocks, with enclosures containing 50% more herbaceous aboveground biomass C stocks than openly grazed land. However, the response of herbaceous aboveground biomass C stocks to grazing was also strongly influenced by the woody encroachment characteristics including woody density, canopy cover, species composition and other specific traits of woody species. Mean total SOC stock in the 0 - 40 cm soil depth ranged from 30 Mg ha-1 in the openly grazed soils at the high woody encroachment site to 81 Mg ha-1 in the enclosure soils at the low encroachment site ha-1. Soil OC and TSN did not differ in the enclosure at heavily encroached sites but were two times as high in enclosures compared to openly grazed soils at low encroached sites. Soil OC was positively related to TSN and soil cation exchange capacity (CEC), but negatively to sand content. Contrary to expectations, SOC stocks did not uniformly follow the pattern of increasing aboveground biomass C stocks with increasing woody encroachment. Rather, it seemed to be influenced by variations in soil characteristics across the Borana rangelands. The study highlights the influence of woody encroachment and reduction of grazing pressure on ecosystem C stocks. The allometric models developed by this study can serve as a tool for future biomass and C sequestration studies in semiarid regions of east Africa. The information presented on the ecosystem C stocks by this thesis could help integrate the effects of grazing and vegetation cover dynamics on the rangeland C storage. An understanding of these interactions are deemed necessary to develop a sound rangeland management policy that can link the C storage potential of the rangelands to global climate change mitigation and adaptation strategies through establishing a viable mechanism of payment for ecosystem services. Das Borana Weideland in Südäthiopien steht vor einer Veschlechterung, die durch intensivierte Beweidung und die Ausbreitung von Gehölzpflanzen verursacht wird. Dies führt zu einer deutlichen Abnahme der pastoralen Produktion und hat auch einen negativen Einfluss auf die Nahrungssicherheit und den Lebensunterhalt der Borana Bevölkerung. Auf der anderen Seite resultiert die Ausbreitung von Gehölzpflanzen möglicherweise in einer erhöhten Kohlenstoffspeicherung, ein wichtiger Aspekt bezüglich des Potentials zur Abmilderung des Klimawandels. Jedoch ist unklar wie viel Kohlenstoff (C) tatsächlich in der ober- und unterirdischen Biomasse und im Boden dieses Weidelandes gespeichert ist und wie Beweidungsintensität und die zunehmende Bedeckung von Gehölzpflanzen die Kohlenstoffvorräte des Ökosystems beeinflussen. Die vorliegende Arbeit hat zum Ziel, Methoden zur Schätzung der oberirdischen Gehölzbiomasse bzw. der C-Vorräte zu entwickeln. Sie beschreibt die Struktur der semiariden Savannenvegetation unter verschiedenen Beweidungsformen, unter zunehmendem Deckungsgrad an Gehölzpflanzen und präsentiert feldbasierte Methoden zur Quantifizierung und standort-basierten Schätzung der ober-und unterirdischen C-Vorräte. Außerdem bezweckt diese Arbeit, den Einfluss von Beweidung auf die ober-und unterirdischen Biomasse bzw. C-Vorräte des Unterwuchses (Krautschicht) zu bewerten sowie den Effekt auf Bodenkohlenstoff (Soil organic carbon – SOC) und Gesamtstickstoff (total soil nitrogen – TSN) abzuschätzen. So kann eine mögliche Zunahme des Ökosystemkohlenstoffvorrats durch langfristige Reduktion der Beweidung (z.B. niedrigere Viehdichte und saisonale Beweidung) unter variierender Gehölzbedeckung eingeschätzt werden. Mittels Satellitenbildern der letzen 37 Jahre, eines Geoinformationssystems (GIS) und Kartierung wurden langfristige und groß-skalige Änderungen der Vegetationsbedeckung untersucht. Im Feld wurden Daten gesammelt, um Vegetationseigenschaften wie Artzusammensetzung und -struktur in Abhängigkeit von Beweidung und Bedeckung zu analysieren. Krautige Arten wurden destruktiv geerntet, um die Biomasse und C-Vorräte zu quantifizieren. Durch destruktives Ernten von acht Baumarten wurden allometrische Modelle entwickelt, um indirekt die hölzerne Biomasse und C-Vorräte zu quantifizieren. Gesamtstickstoff des Bodens und organischer Kohlenstoff (SOC) wurden mittels Bohrkernen von 0-40 cm Tiefe untersucht. Die Güte der allometrischen Biomassemodelle (adj r2) hing von der geschätzen Baumart und Biomassekomponente ab. Bei Baumarten mit hoher Gesamtbiomasse, z.B. A. mellifera, A. bussei und A. etabaica, trafen die allometrischen Modelle sehr akkurat zu. Die wichtigste Prädiktorvariable der Modelle bei hohen Stäuchern mit mehr oder weniger offener Krone war der Basalumfang, während Kronenvolumen und Basalumfang des Stammes die zuverlässigsten Prädiktoren bei Arten mit geschlossener schirmförmiger Kronenstruktur waren. Weiterhin wurde gezeigt, dass die Biomasse von Sträuchern mit büschelartiger Kronenstrukur und mehreren Stämmen (e.g. A. oerfota) auch mittels des Kronenvolumens als alleinigem Prädiktor akkurat bestimmt werden konnte. Die Analyse der Vegetationsbedeckung mittels Landsat Bildern von 1976 bis 2012 zeigte, dass die mit Sträuchern und Baumsavanne bedeckte Fläche seit 1970 von 45% auf 9% abgenommen hat, während die Fläche mit hoher Dichte an Gehölzpflanzen von 22% auf 61% zunahm. Die Häufigkeit von regenerativen Gehölzpflanzen (

L’étude des changements d’occupation et d’usage des sols a émergé comme étant une composante fondamentale des recherches internationales menées sur le changement global. Elle apparaît même depuis une dizaine d’années comme une discipline scientifique à part entière, avec une approche interdisciplinaire solidement ancrée. Le « Land Change Science » vise ainsi à comprendre les dynamiques d’occupation et d’usage des sols comme un système complexe basé sur le couple « homme – environnement » en énonçant et développant des théories, concepts et modèles relevant des sciences sociales et environnementales. Dans ce contexte scientifique, la Géographie joue « naturellement » un rôle prépondérant. Placée à l’interface des sciences environnementales, sociales et humaines, la géographie apparaît ainsi bien représentée dans les programmes internationaux tels que l’IGBP ou l’IHDP. Elle appréhende le changement global en général et les changements d’occupation des sols en particulier en apportant des réponses aux défis de plus en plus médiatisés posés par le changement global. L’expertise et le savoir-faire du géographe apparaissent donc être un atout majeur pour répondre aux défis complexes posés par le changement global. Sa valeur ajoutée réside dans une analyse spatialisée et une contribution importante à la modélisation dynamique des systèmes complexes à l'interface Nature/Société. Mes travaux de recherche s’inscrivent dans cette démarche et tentent de contribuer à cette réflexion. Ils sont centrés sur l’étude des changements d'occupation et d'usage des sols en interaction avec les sociétés humaines et leurs territoires. Parmi ces interactions, l’analyse des interactions entre les changements d'occupation et d'usage des sols et les territoires agricoles est privilégiée. Si mes travaux de recherche concernent surtout des sites expérimentaux localisés en Bretagne (Programme LTER-Europe « Zone Atelier Armorique », programme « Bretagne eau Pure »…), ils intègrent également des sites d’étude localisés dans des pays de la zone intertropicale (Afrique de l’Ouest, Argentine, Inde…). Pouvant paraître à première vue assez différents et éloignés, ces territoires (i.e. Zone HAPEX Sahel, bassin versant du Berambadi en Inde) sont tous soumis à de fortes pressions anthropiques (conflits d’usage, surexploitation des ressources,…). Ils sont étudiés selon une même logique thématique et méthodologique, les méthodes mises au point et appliquées dans une région devant pouvoir être transposables. Ainsi, la Bretagne est considérée dans mes travaux comme une région test où sont élaborées des méthodes dont la reproductibilité est évaluée sur les espaces intertropicaux.

ACL (avec facteur d'impact); International audience; Preservation through legal protection of natural areas is costly and limited in its extent. A much cheaper strategy to preserve natural areas could be to simply identify areas of ecological interest and let it be known. A survey was launched in France to identify such areas (called ZNIEFF) in the early 1980s. Since then, municipalities have had to account for ZNIEFFs in their formal land planning schemes, though they are not under any obligation to protect them. In this study, we tested the effectiveness of ZNIEFFs as a conservation tool in an area of high growth near Paris. Using GAM modeling, we compared the rate of urbanization inside and outside ZNIEFFs in the 17 years following designation, accounting for the share of farmland, the overall rate of urbanization and ZNIEFF proportion in the municipalities, and also accounting for demography and physical constraints (hydromorphy and slope). Overall, there was less urbanization inside ZNIEFFs, but this varied depending on the context. Surprisingly, they were better preserved in areas of more intense urbanization. This effect was increased if farmland area was already reduced (

Several Mediterranean cities underwent important morphological changes in the last century. This article deals with the transition from compact towards dispersed urban form and the consequent changes in Land Cover Relationships (LCRs) observed from 1960 to 2009 in Attica (Greece), a mono-centric, dense city region. We analyzed the long-term spatial distribution of four basic land cover classes to test if the ‘compact growth’ observed up to early 1990s and the ‘sprawl’ observed afterwards differently affect LCRs. Descriptive statistics, correlation analysis and multivariate procedures were used to verify this hypothesis. Results put in evidence similarities and differences in Land Cover Changes (LCCs) and LCRs observed during the two urban phases. Per-capita built-up area was found significantly higher in the ‘sprawl’ than in ‘compact growth’ phase. Cropland was the land cover class with the highest probability to undergo edification in both periods, but a significant conversion rate from forests towards cropland and pastures (in turn converted into built-up areas) was also observed in the ‘sprawl’ phase. This may be considered an indirect effect of urbanization due to sprawl-driven land fragmentation and recurrent fires induced by illegal housing and land speculation. We finally discussed how the changing LCRs may represent, at regional scale, a possible target for policies mitigating land consumption in ‘shrinking’ Mediterranean cities.

Ždimal V.: Infrared images and land cover in the past. Ekológia (Bratislava), Vol. 32, No. 4, p. 383-387, 2013.Czech landscape is an old residential area used by humans since ancient times. At one point, we can follow the traces of human activity from different periods and natural changes. Land cover of one location can change several times. The most important reason is meandering and subsequent straightening of rivers, deforestation, relocation and change in soil layers. These changes in the past affect the present management, and it is important to identify them. A suitable tool for the determination of different sites is remote sensing in the infrared spectrum, which monitors changes in the vegetation, with the support of archival materials. These changes in vegetation are statistically significant and distinct sites with different histories of others. After identifying the different places, one can search the archive materials to know what was the land cover in the past. The following archival materials have been used: maps II and III, military mapping, basic maps and other maps and historical aerial photographs. These images document the landscape before collectivization and the reclamation of the land, which dynamically changed the landscape cover. The studied area was documented by other aerial photographs from other time periods between 1959 and 1989 and mainly infrared images from present were used as the main basis for determining the development of land cover. A comparative analysis of land cover shows the increases and decreases in agricultural land, changes in communication line elements, the impact of new methods of land use, erosion control restoration measures, changes in retention capacity, losses and increase forest, comparing the legal and actual status of the forest boundaries and their changes over time and changes in the built areas.

The interpretation of remotely sensed images in a spatiotemporal context is becoming a valuable research topic for dynamic phenomena. However, constant growth of the amount of data used in the remote image sensing field makes the manual analysis of satellite images a challenging task. Data mining has recently emerged as a promising research field that led to several interesting discoveries related to remote sensing. This thesis presents a new approach based on data mining to predict spatiotemporal land cover changes in satellite image databases. The proposed approach is divided into three steps: spatiotemporal modeling of satellite images, prediction of land cover changes and result interpretation. The proposed approach integrates three levels of imperfection processing: data related, prediction related and results related imperfection. In order to take into account imperfection related to data, a collaborative segmentation is performed. The goal is to reduce information loss when we attempt to model satellite images. Imperfection related to land cover change prediction is processed by applying a fuzzy decision tree in the prediction process. Decisions describing land cover changes are evaluated through a Case Based Reasoning (CBR) in order to retrieve relevant decisions. Upon completion of these individual processes, relevant decisions are combined through a high decision scheme to obtain more accurate and reliable decisions. The experimentation of the proposed approach is divided into two parts: application and evaluation. Results show good performance of the proposed approach measured in terms of precision accuracy comparatively with existing approaches., L'interprétation d'images satellitales dans un cadre spatiotemporel devient une voie d'investigation de plus en plus pertinente pour l'étude et l'interprétation des phénomènes dynamiques. Cependant, le volume de données images devient de plus en plus considérable ce qui rend la tâche d'analyse manuelle des images satellitales plus difficile. Ceci a motivé l'intérêt des recherches sur l'extraction automatique de connaissances appliquée à l'imagerie satellitale. Notre thèse s'inscrit dans ce contexte et vise à exploiter les connaissances extraites à partir des images satellitales pour prédire les changements spatiotemporels de l'occupation du sol. L'approche proposée consiste en trois phases : i) la première phase permet une modélisation spatiotemporelle des images satellitales, ii) la deuxième phase assure la prédiction de changements de l'occupation du sol et iii) la troisième phase consiste à interpréter les résultats obtenus. Notre approche intègre trois niveaux de gestion des imperfections : la gestion des imperfections liées aux données, la gestion des imperfections liées à la prédiction et finalement la gestion des imperfections liées aux résultats. Pour les imperfections liées aux données, nous avons procédé par une segmentation collaborative. Le but étant de réduire la perte d'information lors du passage du niveau pixel au niveau objet. Pour les imperfections liées à la prédiction, nous avons proposé un processus basé sur les arbres de décisions floues. Ceci permet de modéliser les imperfections liées à la prédiction de changements. Finalement, pour les imperfections liées aux résultats, nous avons utilisé les techniques de Raisonnement à Base des Cas et de fusion pour identifier et combiner les décisions pertinentes. L'expérimentation de l'approche proposée est scindée en deux étapes : une étape d'application et une étape d'évaluation. Les résultats d'évaluation ont montré la performance de notre approche mesurée en termes de taux d'erreur par rapport à des approches existantes.

The interpretation of remotely sensed images in a spatiotemporal context is becoming a valuable research topic for dynamic phenomena. However, constant growth of the amount of data used in the remote image sensing field makes the manual analysis of satellite images a challenging task. Data mining has recently emerged as a promising research field that led to several interesting discoveries related to remote sensing. This thesis presents a new approach based on data mining to predict spatiotemporal land cover changes in satellite image databases. The proposed approach is divided into three steps: spatiotemporal modeling of satellite images, prediction of land cover changes and result interpretation. The proposed approach integrates three levels of imperfection processing: data related, prediction related and results related imperfection. In order to take into account imperfection related to data, a collaborative segmentation is performed. The goal is to reduce information loss when we attempt to model satellite images. Imperfection related to land cover change prediction is processed by applying a fuzzy decision tree in the prediction process. Decisions describing land cover changes are evaluated through a Case Based Reasoning (CBR) in order to retrieve relevant decisions. Upon completion of these individual processes, relevant decisions are combined through a high decision scheme to obtain more accurate and reliable decisions. The experimentation of the proposed approach is divided into two parts: application and evaluation. Results show good performance of the proposed approach measured in terms of precision accuracy comparatively with existing approaches.; L'interprétation d'images satellitales dans un cadre spatiotemporel devient une voie d'investigation de plus en plus pertinente pour l'étude et l'interprétation des phénomènes dynamiques. Cependant, le volume de données images devient de plus en plus considérable ce qui rend la tâche d'analyse manuelle des images satellitales plus difficile. Ceci a motivé l'intérêt des recherches sur l'extraction automatique de connaissances appliquée à l'imagerie satellitale. Notre thèse s'inscrit dans ce contexte et vise à exploiter les connaissances extraites à partir des images satellitales pour prédire les changements spatiotemporels de l'occupation du sol. L'approche proposée consiste en trois phases : i) la première phase permet une modélisation spatiotemporelle des images satellitales, ii) la deuxième phase assure la prédiction de changements de l'occupation du sol et iii) la troisième phase consiste à interpréter les résultats obtenus. Notre approche intègre trois niveaux de gestion des imperfections : la gestion des imperfections liées aux données, la gestion des imperfections liées à la prédiction et finalement la gestion des imperfections liées aux résultats. Pour les imperfections liées aux données, nous avons procédé par une segmentation collaborative. Le but étant de réduire la perte d'information lors du passage du niveau pixel au niveau objet. Pour les imperfections liées à la prédiction, nous avons proposé un processus basé sur les arbres de décisions floues. Ceci permet de modéliser les imperfections liées à la prédiction de changements. Finalement, pour les imperfections liées aux résultats, nous avons utilisé les techniques de Raisonnement à Base des Cas et de fusion pour identifier et combiner les décisions pertinentes. L'expérimentation de l'approche proposée est scindée en deux étapes : une étape d'application et une étape d'évaluation. Les résultats d'évaluation ont montré la performance de notre approche mesurée en termes de taux d'erreur par rapport à des approches existantes.

The amount of Biogenic Volatile Organic Compounds (BVOCs) emitted from terrestrial vegetation is of great importance in atmospheric reactivity, particularly, for ozone-forming reactions and as condensation nuclei in aerosol formation and growth (Kavouras et al., 1998). This work presents a detailed inventory for VOCs emissions from vegetation in Italy using an innovative approach. A Geographic Information System (GIS) model was developed to estimate the species-specific BVOC emissions from dominant plant species. The number and type of BVOCs together with the individual values of basal emissions considered in the model were obtained by combining the results obtained in laboratory experiments with those published in literature. The model is unique because until now, biogenic emissions have been expressed only in terms of isoprene and total monoterpenes altogether, while our method provides maps of isoprene and individual monoterpenes at a high-spatial and temporal resolution (~1 km2 and daily time resolutions respectively). The model also introduces the effects of phenological changes of the plant in the emission algorithms of BVOC. Our results show that: a) the main monoterpenes species emitted from Italian forest ecosystems are sabinene and a-pinene; b) annual biogenic isoprene and monoterpene fluxes for the year 2006 were ~27.90 Gg C and ~33.47 Gg C, respectively; c) isoprene, a-pinene, sabinene and b-pinene are the most important compounds emitted from vegetation in Italy; and d) Q. pubescens+Q. petrea+Q. robur, Q. ilex, Q. suber and Fagus sylvatica are the principal BVOC emitting species in the country. The high spatial and temporal resolution, combined with the species-specific emission output, makes the model particularly suitable for assessing local budgets, and for modelling photochemical oxidant at the scale where the ozone pollution is relevant in Italy. An interesting application of the model is the assessment of BVOC emissions due to land use changes produced by biomass burning. This is done through the development of modules to estimate the emissions of pyrogenic and biogenic VOCs. L’emissione di Composti Organici Volatili di origine Biogenica (BVOCs) dalla vegetazione terrestre è di grande importanza nella chimica atmosferica, in particolare, nelle reazioni di formazione di ozono, dei nuclei di condesazione e nella formazione e crescita di aerosol (Kavouras et al., 1998). Questo lavoro, basato su di un approccio innovativo, presenta un inventario dettagliato delle emissioni di VOCs dalla vegetazione italiana,. L’emissione specie specifica di BVOC dalle specie vegetali dominanti è state stimata attraverso lo sviluppo di un modello GIS (Sistema di Informazione Geografico) . Il numero e tipo di BVOCs, assieme ai valori individuali delle emissioni basali considerati nel modello, sono stati ottenuti combinando i risultati degli esperimenti di laboratorio con quelli pubblicati in letteratura. Il modello è unico, perché fino ad ora, le emissioni biogeniche sono state espresse solo in termini di isoprene e monterpeni totali, mentre il nostro metodo fornisce mappe di isoprene e monoterpeni individuali ad alta risoluzione spaziale e temporale (~1 km2 e giornaliera, rispettivamente). Il modello introduce anche gli effetti dei cambiamenti fenologici delle piante negli algoritmi di emissione di BVOC. I nostri risultati mostrano che: a) le principali specie di monoterpeni negli ecosistemi italiani sono sabinene e α-pinene; b) le stime annuali di isoprene e monoterpeni per l’anno 2006 sono state ~27.90 GgC e ~33.47 GgC, rispettivamente; c) isoprene, α-pinene, sabinene and β-pinene sono i composti più importanti emessi dalla vegetazione in Italia; d) Q. pubescens+Q. petrea+Q. robur, Q. ilex, Q. suber e Fagus sylvatica sono le principali specie emettitrici di BVOC nel paese. La elevata risoluzione spaziale e temporale, combinata con le emissioni specie-specifiche di output, rende il modello particolarmente adatto per la valutazione dei bilanci locali, e per la modellizzazione della reattività degli ossidanti fotochimici alla scala in cui l’inquinamento da ozono è rilevante in Italia. Una interessante applicazione del modello è la valutazione delle emissioni di BVOC dovute ai cambiamenti di uso del suolo generati da incendi, che può essere realizzata attraverso lo sviluppo di moduli per la stima di emissioni di VOC prirogeniche e biogeniche. Dottorato di ricerca in Ecologia forestale

3D reconstruction of abandoned settlements of the central Povltaví ABSTRACT This work deals with the use of Geoinformatic systems to create the three-dimensional model of an extinct landscape. The main subject of this bachelor work is the three-dimensional reconstruction of extinct municipalities in the central area of the Vltava River. The main task was to create digital terrain model of the original Vltava valley. The passage from Zvírotice to Svatojánské proudy has been chosen as the model territory. Two selected municipalities Zvírotice and Živohošť were thoroughly worked up. Many data sources were used in this work, such as historical photographs, historical aerial photographs or current orthophoto maps. Digital terrain models were created with the help of these datas and then the models were overlain with the orthophotos. 3D models of buildings and vegetation were put in the terrain models. Two periods were compared, 50th of the 20th century and present. Results of this work are fly-by animations and perspective scenes. The results will be used in newly built museum in Chotilsko town. Keywords: 3D reconstruction, DTM, land cover changes, orthophoto

Accuracy issues of identification possibilities and analyzing digital images of land surface are examined using a covariance method. Digital images received using remote access methods are treated by the computer programes developed in theMatlab 7software package environment. The paper investigates the opportunity to automatically compare two digital images of fragments and determines the interdependence of comparable images. The interdependence of two images is verified according to the calculated values of the correlation coefficient. Considering a more absolute value of the correlation coefficient between compared digital images, dependency is higher and vice versa. Such method could be applied to long-term monitoring in order to control the temporal evolution of selected images. Žemės dangos pokyčių nustatymas atliekant fotografinių vaizdų palyginimą kovariacijos metodu Santrauka.Aprašomas metodas, kuris galėtų būti taikomas atliekant ilgalaikę stebėseną – stebint pasirinktų objektų kitimą laikui bėgant. Nagrinėjama galimybė automatizuotai palyginti du skaitmeninių vaizdų fragmentus ir nustatyti šių lyginamų vaizdų tarpusavio priklausomybę. Skaitmeniniai vaizdai, gauti nuotoliniais metodais, apdorojami pagal sudarytą kompiuterinę programąMatlab 7programinio paketo operatorių aplinkoje. Šia programa tarpusavyje lyginami du skaitmeniniai vaizdai. Jų tarpusavio priklausomybė įvertinama šia programa apskaičiuotomis koreliacijos koeficientų reikšmėmis. Kai koreliacijos koeficiento absoliučioji reikšmė didesnė, priklausomybė didesnė, ir atvirkščiai. Pagal tai galima įvertinti dviejų skaitmeninių vaizdų arba vieno vaizdo dviejų dalių (fragmentų) tarpusavio priklausomybę (panašumą). Reikšminia žodižiai:žemės dangos pokyčiai,kovariacinė funkcija,palyginimas,pikseliai,skaitmeniniai vaizdai. Изменения почвенно-растительного покрова, выявленные при сравнении цифро вых изображений ковариационным методом Резюме.Описывается метод, который может быть применен для долгосрочного мониторинга – наблюдения за изменениями выбранных объектов во времени. Изучается возможность автоматически сравнивать между собой два фрагмента цифровых изображений и определять взаимозависимость этих сравниваемых изображений. Цифровые изображения, полученные дистанционными методами, обрабатываются по созданной компьютерной программеMatlab 7в среде операторов программного пакета. По этой программе сопоставляются два цифровых изображения, взаимозависимость которых оценивается по рассчитанным программой значениям коэффициентов корреляции. При более высоких абсолютных значениях коэффициента корреляции взаимозависимость более высокая и наоборот. По этим значениям можно оценить взаимозависимость (сходство) двух цифровых изображений или двух частей (фрагментов) одного изображения. Ключевые слова:изменения почвенно-растительного покрова,ковариационная функция,сравнение,пиксели,цифровые изображения.

This thesis deals with the evaluation of land cover changes in twelve cadastral areas in the central part of the Bohemian Forest. This area was gradually abandoned due to political changes in the 20th century. For the purpose of this study, the historical Stabile Cadastre maps from 1837 and aerial photographs from 1949 and 2008 are used. The work follows both the development of the area as a whole and the development of the individual segments around the "Iron Curtain ", built after the World War II. Another aim of this work is to determine the spatial distribution of trees in an open countryside. Field data are supplemented with the features calculated from the digital elevation model and the distances of each species to man-made landscape elements present in the area around the time of displacement (aerial photos from 1949).

66 Pag., 5 Fig. The definitive version is available at: http://www.sciencedirect.com/science/journal/00128252, Mediterranean areas of both southern Europe and North Africa are subject to dramatic changes that will affect the sustainability, quantity, quality, and management of water resources. Most climate models forecast an increase in temperature and a decrease in precipitation at the end of the 21st century. This will enhance stress on natural forests and shrubs, and will result in more water consumption, evapotranspiration, and probably interception, which will affect the surface water balance and the partitioning of precipitation between evapotranspiration, runoff, and groundwater flow. As a consequence, soil water content will decline, saturation conditions will be increasingly rare and restricted to periods in winter and spring, and snow accumulation and melting will change, especially in the mid-mountain areas. Future land management will be characterized by forest and shrub expansion in most Mediterranean mountain areas, as a consequence of farmland and grazing abandonment, with increasing human pressure localized only in some places (ski resort and urbanized of valley floors). In the lowlands, particularly in the coastal fringe, increasing water demand will occur as a consequence of expansion of irrigated lands, as well as the growth of urban and industrial areas, and tourist resorts. Future scenarios for water resources in the Mediterranean region suggest (1) a progressive decline in the average streamflow (already observed in many rivers since the 1980s), including a decline in the frequency and magnitude of the most frequent floods due to the expansion of forests; (2) changes in important river regime characteristics, including an earlier decline in high flows from snowmelt in spring, an intensification of low flows in summer, and more irregular discharges in winter; (3) changes in reservoir inputs and management, including lower available discharges from dams to meet the water demand from irrigated and urban areas. Most reservoirs in mountain areas will be subject to increasing water resource uncertainty, because of the reduced influence of snow accumulation and snowmelt processes. Besides, reservoir capacity is naturally reduced due to increasing sedimentation and, in some cases, is also decreased to improve the safety control of floods, leading to a reduction in efficiency for agriculture. And (4) hydrological and population changes in coastal areas, particularly in the delta zones, affected by water depletion, groundwater reduction and saline water intrusion. These scenarios enhance the necessity of improving water management, water prizing and water recycling policies, in order to ensure water supply and to reduce tensions among regions and countries., This work was supported by research projects CGL2006-11619/HID, CGL2008-01189/BTE, and CGL2008-1083/CLI, financed by the Spanish Commission of Science and Technology, and FEDER, EUROGEOSS (FP7-ENV-2008-1-226487) and ACQWA (FP7-ENV-2007-1-212250, financed by the European Commission, the VII Framework Programme financed by the European Commission, the project “Las sequías climáticas en la cuenca del Ebro y su respuesta hidrológica” and “La nieve en el Pirineo aragonés: Distribución espacial y su respuesta a las condiciones climáticas”, financed by “Obra Social La Caixa” and the Aragón Government, and “Programa de grupos de investigación de excelencia”, financed by the Aragón Government.

International audience; Mediterraneanlandscapesresultedfromthecomplexandancientinteractionofecosystemsandsocieties. Today they represent one of the world’s biodiversity hotspots. These landscapes have a fine-grained mosaic and a high resilience to disturbances. However, during the last century, human pressures have led to new landscape structures and dynamics and an overall decrease in biological diversity. Within a Mediterranean landscape from southern France, we assessed the effects of land use changes on land cover and biodiversity over the last 60 years. The major land use changes involved a substantial decrease in sheep grazing and wood cutting corresponding to the abandonment of 70% of the study area. This resulted in a reduction in land use diversity which was usually high in the Mediterranean. Although land cover in the study area changed gradually (2.2% per year), over 74% changed between 1946 and 2002. This habitat shift had a subsequent impact on species distribution. Apart from amphibians and insects, most species of birds, reptiles, orchids and rare plants that responded positively to these changes were associated with woodlands, while species that responded negatively were associated with open habitats. In the Mediterranean, most rare and endemic species are associated with open habitats and are thus threatened by land abandonment. As a result, land abandonment is contributing to a decrease in local species richness and a decrease in rare and endemic species. Since similar patterns of change have been observed over most of the north-western Mediterranean, land abandonment represents a major threat for biodiversity in the Mediterranean.

Research Proposal for the Research Stay at the Arctic Centre, University of Lapland under the CIMO Scholarship. Reindeer are unique part of the northern environmental in Lapland. For the comfortable existing they need large areas of herding pastures for grazing. The anthropogenic activities may influence the ecosystems where pastures are based in a negative way: mining, logging, oil and gas exploration, hydro power development as well as other human activities encroaching to the traditional habitats of reindeers and threatening the herding areas. Finally, climate changes influence natural environment and biodiversity of the northern ecosystems. All these factors lead to negative changes in the structure of landscapes, patterns defragmentation, decrease of biodiversity, and worsening of life conditions for the reindeer existence. The dynamics of these changes must be evaluated for the monitoring and sustainable development of the unique Lappish landscapes in the northern Finland. The proposed research focuses on the spatial GIS analysis and raster-based mapping of the changes in landscapes and land cover in the areas of reindeer herding pastures in High Arctic (Finnish Lapland).

Analysis of land use and land cover changes are fundamental for assessments related to climate and emission inventories. There are complex interactions between land use/cover changes and climate changes often linked by feedbacks that make it difficult to distinguish impacts from causes (Verburg et al., 2009). Land use and land cover information mainly are from cartographic, census data and surveys data. Data comparison from different sources is often hampered by problems of uncertainty and inconsistency due to differences in definition of land use and land cover classification, temporal and spatial scale. An analysis of these inconsistencies could help to make more appropriate use of the data in climate change assessments. Land use and land cover are not the same. The land use function of a land cover type needs to be known in order to understand changes in land cover (Pelorosso et al., 2009). This study provides a method to compare data from different sources, a historical and a recent remote sensing-derived map, by homogenized them in order to reduce misleading changes and to assess spatial aggregation errors. This was done through a data integration procedure based on landscape metrics. The results allowed the different dynamics of a wide area in central Italy to be identified, bringing to light divergences between the trends suggested by census and cartographic data. The presented method could be used to assess and improve land use/cover changes analysis either if based only on land use census data or if based on land cover cartographic data.

Changes of vegetal cover in the Aragonese western Pyrenees are shown throughout the last 50 years. The evolution is characterized by a generalised revegetation process with an advance of shrubs and forests. The medium and low slopes show the most intense revegetation as a consequence of the agricultural abandonment and the decrease of the livestock pressure. Nevertheless, few vegetation changes are recorded in cultivated lands and the pastures located above timberline. In the analysed period, the most important changes were recorded in the decades of 1960 and 1970 whereas in the decades of 1980 and 1990 the rate of vegetation growth has decreased noticeably. The socioeconomic factors (agricultural abandonment, livestock extensification and reforestations) affect the spatial and temporal patterns of revegetation. Also the relief has a noticeable influence, mainly elevation and aspect., En este trabajo se muestran los cambios de cubierta vegetal en el Pirineo occidental aragonés entre 1957 y 2007. La evolución se caracteriza por un importante proceso de revegetación con avance de los matorrales de sucesión y del bosque. Las laderas medias y bajas son las áreas con un proceso de revegetación más intenso, como consecuencia del abandono agrícola y la baja presión ganadera. Los avances más modestos tienen lugar en el espacio cultivado y pastos alpinos. Entre los años sesenta y ochenta ocurrieron los mayores cambios en la cubierta vegetal, habiéndose ralentizado en las dos últimas décadas. Los factores socioeconómicos (abandono agrícola, extensificación ganadera y reforestaciones) son los más influyentes, mientras que entre las naturales tiene especial importancia la exposición.

30 páginas, 9 figuras, 6 tablas., [ES] En este trabajo se muestran los cambios de cubierta vegetal en el Pirineo occidental aragonés entre 1957 y 2007. La evolución se caracteriza por un importante proceso de revegetación con avance de los matorrales de sucesión y del bosque. Las laderas medias y bajas son las áreas con un proceso de revegetación más intenso, como consecuencia del abandono agrícola y la baja presión ganadera. Los avances más modestos tienen lugar en el espacio cultivado y pastos alpinos. Entre los años sesenta y ochenta ocurrieron los mayores cambios en la cubierta vegetal, habiéndose ralentizado en las dos últimas décadas. Los factores socioeconómicos (abandono agrícola, extensificación ganadera y reforestaciones) son los más influyentes, mientras que entre las naturales tiene especial importancia la exposición., [EN] Changes of vegetal cover in the Aragonese western Pyrenees are shown throughout the last 50 years. The evolution is characterized by a generalised revegetation process with an advance of shrubs and forests. The medium and low slopes show the most intense revegetation as a consequence of the agricultural abandonment and the decrease of the livestock pressure. Nevertheless, few vegetation changes are recorded in cultivated lands and the pastures located above timberline. In the analysed period, the most important changes were recorded in the decades of 1960 and 1970 whereas in the decades of 1980 and 1990 the rate of vegetation growth has decreased noticeably. The socioeconomic factors (agricultural abandonment, livestock extensification and reforestations) affect the spatial and temporal patterns of revegetation. Also the relief has a noticeable influence, mainly elevation and aspect., [FR] Les changements de la couverture végétal entre 1957 et 2007 sont analysés dans les Pyrénées occidentales aragonaises. L´évolution se caractérise par un important processus de revégétation avec une progression des buissons et de la forêt. Les versants moyens et bas sont les zones qui présentent un processus de revégétation plus intense, conséquence de l´abandon agricole ainsi que de la faible pression de l´élevage. Des progressions moins importantes ont lieu dans les espaces cultivés et dans les pâturages alpins. Des changements majeurs se sont produits entre les années soixante-dix et quatre-vingts, et ensuite un ralentissement pendant les deux dernières décennies. Les facteurs socio-économiques (l´abandon agricole, l´extensification de l´élevage et le reboisement) ont un poids plus important que les facteurs naturels, parmi lesquels l´exposition est celui qui a une influence majeure. Les résultats indiquent que la progression est un processus modéré (1 ou 2 stades dans le processus de succession), conséquence du peu de temps qui s’est écoulé depuis la réduction de la pression humaine sur le territoire., Este trabajo ha contado con la financiación de los siguientes proyectos: CGL2005-04508/BOS, CGL2005-04863/CLI y CGL2006-11619HID, financiados por la CICYT y FEDER, PIP176/2005 y Programa de grupos de investigación consolidados financiados por el Gobierno de Aragón (BOA 48, 20-04- 2005).

[EN] This paper analyses the evolution of the Normalized Difference Vegetation index (NDVI) in the central Spanish Pyrenees. For this purpose, Landsat-TM and ETM+ were used. The selected images correspond to August of 1984, 1991 and 2001. The difference in days between the images was not very important to diminish the effects of phenology. The images were geometrically and atmospherically corrected by means of a mixed method based on physical and statistical procedures. Using the NDVI images we calculated coefficients of variation within a radius of 150 meters by means of a moving window procedure. This approach allows to analyse the spatial variability of the vegetation cover. The results show that the NDVI changes have not been important in the analysed period. Nevertheless, there are noticeable modifications in the spatial structure and variability of the NDVI, resulted in homogeneization/heterogeneisation processes. The forests located at high altitudes have suffered the most important homogeneization processes. On the contrary at low elevated areas the spatial diversity of the vegetation activity increases. Nevertheless, in these areas some spatial differences are found: the heterogenisation of the vegetation cover is less important in the forests than in areas dominated by sclerophyllous vegetation and those characterised by the transition from shrubs to forests. These areas show less mature successional phases after the land abandonment and they are characterised by and increase of the spatial heterogeneity of the NDVI., [ES] RESUMEN.— Se analiza la evolución temporal del índice de vegetación normalizado (Normalizad Difference Vegetation Index, NDVI), obtenido a partir de imágenes Landsat-TM y ETM+, en un sector del Pirineo central español. Se han utilizado tres imágenes de agosto de los años 1984, 1991 y 2001, con una escasa diferencia en días en la toma de las mismas para garantizar la homogeneidad en la fenología de la vegetación. Las imágenes fueron corregidas geométrica y atmosféricamente siguiendo un método mixto basado en un modelo físico y procedimientos estadísticos. A partir de las imágenes de NDVJ se han calculado coeficientes de variación móviles en un radio de 150 metros, para analizar la variabilidad espacial en la actividad vegetal. Los cambios en el NDVI han sido poco importantes durante el periodo analizado, existiendo escasas diferencias entre las tres imágenes. Sin embargo, sí se han producido cambios apreciables en la variabilidad espacial de la actividad vegetal, como consecuencia de procesos de homogeneización/heterogeneización. Se ha comprobado que en las áreas de bosques localizadas a mayor altitud se ha producido un proceso de homogeneización de la cubierta vegetal. Por el contrario, en las partes más bajas se ha incrementado la diversidad espacial, reflejando un dominio de procesos de heterogeneización. Esta ha sido menor en las zonas de bosque que en las áreas cubiertas por vegetación esclerófila y en las de transición matorral/bosque, espacios que se encuentran en fases más tempranas de sucesión tras el abandono agrícola y en las que la sucesión se caracteriza por un aumento de la heterogeneidad espacial., Este trabajo ha contado con la financiación de los siguientes proyectos: STRIVER, financiado por la Comisión Europea (VI Programa Marco), CANOA: CGL 2004-04919-C02-01, CGL2005-04508/BOS, RS-FIRE: CGL2005-04863/CLI y CGL2006-11619HID, financiados por la CICYT y FEDER, PIP176/2005 y el Programa de grupos de investigación consolidados financiados por el Gobierno de Aragón (BOA 48, 20-04-2005).

Submitted by Admin Dspace (suporte@uatlantica.pt) on 2012-02-08T15:49:15Z No. of bitstreams: 1 2005_Alencoast_I&CLC2000_Applications.pdf: 1131066 bytes, checksum: 89338c6bb71bc6d530a9dde3672ea58d (MD5) Submitted by Admin Dspace (suporte@uatlantica.pt) on 2012-02-17T17:04:34Z No. of bitstreams: 1 2005_Alencoast_I&CLC2000_Applications.pdf: 1131066 bytes, checksum: 89338c6bb71bc6d530a9dde3672ea58d (MD5) Approved for entry into archive by Admin Dspace (suporte@uatlantica.pt) on 2012-02-17T17:04:49Z (GMT) No. of bitstreams: 1 2005_Alencoast_I&CLC2000_Applications.pdf: 1131066 bytes, checksum: 89338c6bb71bc6d530a9dde3672ea58d (MD5) Approved for entry into archive by Admin Dspace (suporte@uatlantica.pt) on 2012-02-17T17:05:07Z (GMT) No. of bitstreams: 1 2005_Alencoast_I&CLC2000_Applications.pdf: 1131066 bytes, checksum: 89338c6bb71bc6d530a9dde3672ea58d (MD5) Made available in DSpace on 2012-02-17T17:05:07Z (GMT). No. of bitstreams: 1 2005_Alencoast_I&CLC2000_Applications.pdf: 1131066 bytes, checksum: 89338c6bb71bc6d530a9dde3672ea58d (MD5) Previous issue date: 2005

Presented at Society for Applied Anthropology Annual Meeting, Santa Fe, New Mexico, April 8, 2005. BA-2 (SANREM-Andes Research)

Metadata only record This article examines changes in land cover and land use in forested regions as major contributors to global environmental change. The author also investigates why some forested areas thrive even in the presence of high human densities and activity while others decline and disappear.

This study assessed changes in forest cover in a mountain watershed in central Nepal between 1976 and 2000 by comparing classified satellite images coupled by GIS analyses, and examined the association of forest change with major physiographic, economic, and local forest governance parameters. The results showed an increase in forested area (forest plus shrublands) by 7.6% during 1976–2000. Forest dynamism (changes including improvement, deterioration, gain, and loss) was highest in low-elevation, south-facing and less-steep slopes that were closer to roads. Proportionately the highest net improvement and gain to forested area also took place in those locations. Forest degradation occurred at twice the rate of improvement in high elevation areas (> 2300 m). Forests located in urban and semiurban areas (i.e., a market-oriented economy) experienced a proportionately higher amount of net improvement and gain than forests in rural areas (i.e., a subsistence economy). Among the three governance arrangements, proportionately the highest net improvement and gain took place in semigovernment forests (forested area legally under the forest department but with de facto control and claim of ownership by local communities and/or municipality) followed by formalized community forests (including leasehold). Government forests, which were mostly found in the southern high mountains and had virtually open access, remained relatively stable during the study period. Over 50% of the watershed forests have not come under community-based management despite favorable policy and more than two decades of government intervention with continuous donor support. The findings indicate that the present “one size fits all” approach of community forest handover policy in Nepal needs rethinking to accommodate biophysical and socioeconomic variations across the country.

International audience; In intensive agricultural regions, accurate assessment of the spatial and temporal variation of winter vegetation is a key indicator of water transfer processes, essential for controlling land management and helping local decision making. Spatial prediction modeling of winter bare soils is complex and it is necessary to introduce uncertainty in modeling land use and cover changes, especially as high spatial and temporal variability are encountered. Dempster's fusion rule is used in the present study to spatially predict the location of winter bare fields for the next season on a watershed located in an intensive agricultural region. It expresses the model as a function of past-observed bare soils, field size, distance from farm buildings, agroenvironmental action, and production quotas per ha. The model well predicted the presence of bare soils on 4/5 of the total area. The spatial distribution of misrepresented fields is a good indicator for identifying change factors.

Metadata only record Dryland degradation rarely translates into linear, declining trends in vegetation cover due to interannual climatic variability. Appropriate indicators of land-cover modifications need to be defined for semi-arid regions. Our hypothesis is that degradation can be measured by: (1) a decrease in the resilience of vegetation to droughts; (2) a decrease in rain-use efficiency; and (3) a modification of floristic composition. The objective of this paper is to test the relationships between a remotely sensed indicator of vegetation, rainfall data and field measurements of biomass and floristic composition. The study was based on field measurements of vegetation conditions covering a period of 10 years, in the semi-arid region of the Ferlo in Senegal. Our results indicate that land-cover modifications in the Ferlo are best measured by changes in rain-use efficiency. No consistent trend in the relative abundance of grass species was visible at the scale of the decade, even on the two sites affected by degradation. Just after a drought, a given increase in rainfall results in less biomass production than is the case for normal years. ---Academic Press

Submitted by Admin Dspace (suporte@uatlantica.pt) on 2012-02-27T15:01:57Z No. of bitstreams: 1 1999_GOA_Land-use_changes_methodological_approach.pdf: 24353 bytes, checksum: b600d82ae982224c512dbfc0ac1f5c8b (MD5) Approved for entry into archive by Admin Dspace (suporte@uatlantica.pt) on 2012-02-27T16:38:50Z (GMT) No. of bitstreams: 1 1999_GOA_Land-use_changes_methodological_approach.pdf: 24353 bytes, checksum: b600d82ae982224c512dbfc0ac1f5c8b (MD5) Approved for entry into archive by Admin Dspace (suporte@uatlantica.pt) on 2012-02-27T16:41:03Z (GMT) No. of bitstreams: 1 1999_GOA_Land-use_changes_methodological_approach.pdf: 24353 bytes, checksum: b600d82ae982224c512dbfc0ac1f5c8b (MD5) Made available in DSpace on 2012-02-27T16:41:03Z (GMT). No. of bitstreams: 1 1999_GOA_Land-use_changes_methodological_approach.pdf: 24353 bytes, checksum: b600d82ae982224c512dbfc0ac1f5c8b (MD5) Previous issue date: 1999

Good understanding of relations between historical land cover changes and accompanying environmental components should be a starting point for landscape modelling and forecasting its future patterns. Analysis presented here focuses on the relationships between chosen environmental conditions and agricultural land cover changes in the period of over 150 years. The study area consisted of fragments of Nidziańska Basin and South Pomeranian Lake District macroregions. The land cover data was derived from a number of archival and contemporary topographical maps. Long-term changes of land cover were then related to underlying landscape elements (geological deposits and morphometric landforms). With the help of canonical analysis major correlations were identified and described.

The aim of this study is to reconstruct land use on the floodplain of the changes in the valley was based on archival materials, such as the plan of the Wisła valley from the mid-18th c., and the Prussian and Austrian topographical maps from the 1860s. As the analysis of land use changes in the floodplain of the Mała Wisła valley indicates, in the years 1754-1860 the biggest change referred to the area of forests and shelterbelts, because in a hundred years it decreased three times, i.e. from 3.18 km2 to 1.05 km2. Other big changes include a diminished number and area of fish ponds, as well as smaller surface of the hydrographic network. The layout and area of low density dwellings remained almost unchanged, as a reported increase in the surface area of this form of land use was only by about 0.4%. Significant changes in the surface of ponds and water reservoirs took place in the 1950s, when a dam reservoir was built in Goczałkowice. Its caused an increase the ponds and reservoirs surface to 23.45 km2, which is over 64.7% of the grounds.

International audience