Land alterations including deforestation, unsustainable land management practices and an increase in cultivated areas have occurred in the Upper Ruvu watershed in recent decades threatening water and natural resources. This study, which used a combination of remote sensing techniques, field experiments, watershed monitoring, and modeling was designed to investigate impacts of environmental changes on hydrology and soil erosion. The objectives were to: map the extent of land use and land cover change and its influence on soil erosion; correlate the contribution of climate variability and human activities to the changes in hydrology at headwater and watershed scales; estimate surface runoff, sediments and Curve Number at plot scale, and model streamflow responses to changes in land use and land cover using the SWAT watershed model. Results indicate that areas covered by forest decreased from 17% in 1991 to 4% of the total watershed area in 2015. However, areas covered by cropland increased from 14% to 30% of the total watershed area from 1991 to 2015, respectively. Further, results indicate that site characteristics affect runoff and sediment yield as higher soil loss was estimated from cropland with a mean of 28.4 tha-1 in 2015 from 19.8 tha-1 in 1991. Results from monitoring show high sediment loads were from the most disturbed watersheds, compared to Mbezi. Analysis of trends for the long term records at the watershed showed that rainfall had significant decreasing trends. At annual scale, climate variability contributed 46% and human activities contributed 54% of the changes in streamflow. Results from the rainfall simulation experiments show upland rice had higher runoff (48 mmh-1) and soil loss (94 gm-2) compared to grassland and forest. Results from the model outputs showed that average streamflow decreased by 13% between 1991 and 2015. Average peak flows increased by 5% and 12% for 2000 and 2015, respectively compared to the baseline. Land alterations had impacts on surface runoff which increased by 75% and baseflow decreased by 66% in 2015 from the baseline. These results highlight the main areas of changes and provide quantitative information to decision makers for sustainable land and water resources planning and management. / Ph. D.

On étudie une zone de la Cordillère de la Costa au sud du Chili (41°15'S-41°00'S), habitée par l'ethnie Mapuche. Là, il y a encore des précieuses forêts tempérées, qui ont une haute priorité de conservation au plan mondial. Mais, il est constaté, un processus continu de transformation lié à l'extraction de bois de chauffe, l'élevage extensif, la perturbation de l'habitat du conifère Fitzroya cupressoides, et le déploiement des plantations forestières. Sur la base d'une classification multi-temporelle d'images satellite, une modélisation spatio-temporelle a été mise en œuvre pour comprendre et anticiper la dynamique de la détérioration de la forêt. L'analyse rétrospective révèle qu'entre 1976 et 2008, la forêt a été réduite 12400 ha, soit un taux de déforestation 0,25% par an. 20 modèles de déforestation sont calibrés, 4 d'entre eux sont sélectionnés pour construire des scénarios prospectifs. La simulation prévoit que la diminution de forêt entre 2008 et 2040 pourrait atteindre 13000 ha. Deux autres modèles mis en œuvre simulent l'évolution de la qualité de l'habitat de F. cupressoides. Les scénarios prévoient une augmentation de la surface détériorée ; l’extrapolation à partir de la période d’apprentissage 2001-2008 pendant laquelle la plus grande part de terres indigènes a été légalisée, par rapport à la période précédente à 2001, prédit une augmentation plus significative de la surface détériorée. On fournit un outil pour amplifier la gestion territoriale des systèmes environnementaux toujours non incorporée dans la planification chilienne. Enfin, la thèse met également d'intéressantes comparaisons entre modèles qui diffèrent par rapport aux paramètres de calibration. / SAn area of the Cordillera de la Costa is studied in southern Chile (41°15'S - 41°00'S), inhabited by ethnic Mapuche. There are still valuable temperate forests that have high conservation priority worldwide. But it is found, a continuous process of transformation related to the extraction of firewood, ranching, disruption of habitat conifer Fitzroya cupressoides, and deployment of forest plantations. Based on a multi-temporal satellite images classification, a spatial-temporal modeling was implemented to understand and predict the dynamics of the deterioration of the forest. Retrospective analysis revealed that between 1976 and 2008, the forest has been reduced 12,400 ha, a deforestation rate of 0.25% per annum. 20 models of deforestation are calibrated, 4 of them are selected to construct scenarios. The simulation predicted that reductions of forest between 2008 and 2040 could reach 13,000 ha. Two other models implemented simulate changes in habitat quality F. cupressoides. Scenarios predict an increase in the damaged surface; extrapolating from the learning period 2001-2008 during which the largest share of indigenous lands was legalized, compared with the previous period to 2001, predicts a significant increase in the damaged surface. In this way, it provides a tool to enhance the local management of environmental systems still not incorporated into the Chilean planning. Finally, the thesis also makes interesting comparisons between models that differ with respect to the calibration parameters.

Changing land cover from prairie grasslands to intensive, primarily cereal agriculture, over the North American Great Plains since the mid-19th century, has had a hydrological and climatological impact on that ecosystem (Pielke, Sr., et al., 2011). Agriculture has introduced timed harvest seasons, irrigation, and C3 photosynthesizing crops with poorer water efficiency than the grasses it replaced. All of these changes have been linked to exacerbated drought conditions and warmer temperatures; however, few studies have quantified this relationship at the continental scale. In order to evaluate the change imposed by this shift in land use and land cover, the observation based 20th Century Reanalysis Project (20CR) was used to quantify the climatological differences in temperature and humidity between areas of natural prairie and agriculture over the 20th century. An additional analysis used the Observation Minus Reanalysis (OMR) technique to isolate the surface climate signal found in the 20CR. We find indications that changing land cover had an impact on climate. However, using observation based data returned no evidence of a statistically significant change due to the small land use and land cover change (LULCC) signal within the larger climate noise. Therefore, an idealised modelling experiment was undertaken using the Geophysical Fluid Dynamics Laboratory (GFDL) AM2-LM2 atmosphere-land model to remove these other influences. This experiment compared the results of two model simulations: one where the entirety of the prairie was preserved as grassland (GRASS), and another where the entire prairies had been converted into an agricultural area (AGRIC). Relative to GRASS, the AGRIC simulation has reduced surface albedo and root zone depth, and increased roughness length over the prairies, which collectively cause a significant summer drying. This occurs when the shallower rooting zone limited potential evapotranspiration (PET) forcing the additional energy created by turbulent mixing and a lower surface albedo to warm the air, surpassing PET and reaching drier conditions faster. While not conclusive, the results presented in this thesis represent a step towards filling the gaps in understanding land-atmosphere interactions and connecting LULCC to climate.

Naturschutzgebiete sind ein essentieller Bestandteil zur Wahrung natürlicher Lebensräume. Oft verfehlt die Einrichtung solcher Schutzzonen jedoch den erwarteten Effekt. Die größte Gefahr liegt hierbei neben dem Klimawandel im direkten Einfluss des Menschen. Besonders in Phasen sozioökonomischen Umschwungs und damit verbundenen Landnutzungsveränderungen oder auch illegaler Nutzung natürlicher Ressourcen, sind Naturschutzgebiete in ihrer Funktion gefährdet. Ziel dieser Arbeit ist somit, Ursachen des Landnutzungswandels sowie dessen Auswirkungen und Ausmaß am Beispiel des rumänischen Teils der Karpaten-Ökoregion abzuleiten. Das Untersuchungsgebiet ist ein wichtiges Zentrum für Biodiversität und in ihm befindet sich Osteuropas größte gemäßigte Waldregion sowie einige der letzten europäischen Urwälder. Rumänien umschließt mehr als die Hälfte der Karpaten und es ist hiernach von besonderem Interesse, Gründe und Auswirkungen des rezenten post-sozialistischen Landschaftswandels zu untersuchen. Mit Hilfe von Landsat Aufnahmen sowie einer ad hoc entwickelten Methode zur Klassifizierung großräumiger Gebiete, wurden Veränderungen in der Waldbedeckung für die post-sozialistische Zeit abgeleitet. Die Ergebnisse offenbaren großflächige Forstveränderungen, auch innerhalb von Naturschutzgebieten und Urwäldern. Institutionelle Umbrüche und eine rapide Umgestaltung in den Eigentumsverhältnissen, wurden als Hauptursachen herausgestellt. Rumänische Naturschutzgebiete erreichen nicht die gewünschte Effektivität und Urwäldern werden weiterhin dezimiert. Die Arbeit verdeutlicht den Einfluss sozioökonomischer Veränderungen auf die Entstehung von Raubbau und legt Defizite in der Effektivität von Schutzbemühungen zum Erhalt der Biodiversität und verbundener Ökosystemleistungen offen. / Protected areas are one cornerstone of conservation efforts to safeguard natural habitats from destruction and overexploitation. Still, many of these areas remain less effective than initially envisioned. Besides climate change, main threats originate from enduring human activities. Protected areas are particularly at risk during periods of rapid socio-economic changes, which can trigger widespread land-use change and illegal resource use. The main goal of this thesis is to assess the extend and underlying causes of land-use change in protected areas and forest habitats within the Carpathian Ecoregion. The Romanian Carpathians were selected as a focus area in this study, because they comprise Eastern Europe’s largest continuous temperate forest region as well as some of the last and largest tracts of European old-growth forests, and they are a major hotspot of biodiversity. Romania comprises more than half of the Carpathian Ecoregion and it is of particular interest to study the causes and effects of land-use changes, which have emerged after the collapse of socialism in 1989. Post socialist forest cover change was quantified for the last 25 years using Landsat images and an ad hoc developed large area classification technique. Results show widespread forest disturbances, even inside protected areas and old-growth forests. Drivers of these disturbances can be related to institutional change and changes in ownership. The effectiveness of Romania’s protected area network in terms of its ability to safeguard biodiversity is most likely decreasing, and intact old-growth forests continue to disappear. This thesis reveals how rapid socio-economic changes may lead to overexploitation, and highlights substantial shortcomings in the effectiveness of protection efforts to safeguard biodiversity and related ecosystem services.

Au cours des dernières décennies, l'Indonésie a connu des transformations spectaculaires des terres avec une expansion des plantations de palmiers à huile au détriment des forêts tropicales. L'Indonésie est actuellement l'une des régions ayant le plus haut taux de transformation de la surface terrestre dans le monde à cause de l'expansion des plantations de palmiers à huile et d'autres agricultures qui remplacent les forêts à grande échelle. Comme la végétation est un modificateur du climat près du sol, ces transformations à grande échelle ont des impacts majeurs sur les variables biophysiques de surface telles que la température de surface, l'albédo, les indices de végétation (NDVI), sur le bilan énergétique de surface et le partitionnement énergétique. Ce travail de thèse vise à quantifier les impacts des changements d’usage des terres en Indonésie sur les variables biophysiques de surface. Pour évaluer ces changements à l'échelle régionale, des données de télédétection sont nécessaires. Étant une variable clé de nombreuses fonctions écologiques, la température de surface (LST) est directement affectée par les changements de la couverture terrestre. Nous avons analysé la LST à partir de la bande thermique d'une image Landsat et produit une carte de température de surface avec une haute résolution (30m) pour les basses terres de la province de Jambi à Sumatra (Indonésie), une région qui a subi de grandes transformations au cours des dernières décennies. La comparaison des LST, albédo, NDVI et évapotranspiration (ET) entre sept différents types de couverture terrestre (forêts, zones urbaines, terres incultes, plantations de palmiers à huile jeunes et matures, plantations d'acacias et de caoutchouc) montre que les forêts ont des températures de surface inférieures à celles des autres types de couvert végétal, ce qui indique un effet de réchauffement local après la conversion des forêts vers des plantations. Les différences de LST atteignaient 10,1 ± 2,6 ºC (moyenne ± écart-type) entre les forêts et les terres déforestées. Les différences de températures de surface s'expliquent par un effet de refroidissement évaporatif des forêts, qui compense l'effet de réchauffement de l'albédo. Basé sur des différences observées dans les variables biophysiques entre les plantations de palmiers à huile jeunes et matures, nous avons analysé trois images Landsat couvrant une chronoséquence de plantations de palmiers à huile pour étudier la dynamique des variables biophysiques de surface pendant le cycle de rotation de 20-25 ans des plantations de palmiers à huile. Nos résultats montrent que les différences entre les plantations de palmiers à huile à différents stades du cycle de rotation du palmier à huile se reflètent dans les différences du bilan énergétique de surface, du partitionnement énergétique et des variables biophysiques. Au cours du cycle de rotation des plantations de palmiers à huile, les différences de température à la surface diminuent graduellement et se rapprochent de zéro autour du stade mature de la plantation de palmiers à huile de 10 ans. Parallèlement, le NDVI augmente et l'albédo diminue à proximité des valeurs typiques des forêts. Le bilan énergétique de surface et le partitionnement énergétique montrent des tendances de développement liés aux variables biophysiques et à l'âge des plantations de palmiers à huile. Les nouvelles plantations et les jeunes plantations (<5 ans) ont un rayonnement net plus faible que les plantations de palmiers à huile matures, mais ont des températures de surface plus élevées que les plantations de palmiers à huile matures. Les changements dans les variables biophysiques, le bilan énergétique et la répartition de l'énergie au cours du cycle d’une rotation du palmier à huile peuvent s'expliquer par l'effet de refroidissement évaporatif précédemment identifié dans les forêts, qui compense l'effet de réchauffement de l'albédo. L'un des principaux déterminants de ce mécanisme est la couverture végétale au cours des différentes phases du cycle de rotation du palmier à huile. Le NDVI en tant qu'indicateur du couvert végétal a montré une relation inverse cohérente avec LST de différentes plantations de palmiers à huile âgés, une tendance qui est également observée pour différents types d'utilisation des terres dans cette étude. Une analyse régionale et à plus long terme de la tendance LST entre 2000 et 2015 basée sur les données MODIS montre que dans la journée la température moyenne de Jambi a augmenté de 1,05 ºC, suivant la tendance des changements observés et dépassant les effets du réchauffement climatique. Afin d'évaluer les effets de l'expansion du palmier à huile sur le climat, le bilan énergétique de surface, le partitionnement énergétique et les processus biophysiques jouent un rôle important et le cycle complet de rotation des plantations de palmiers à huile doit être envisagé. Basé sur nos résultats, nous construisons le cycle de rotation des plantations de palmiers à huile et les changements qui se produisent au cours du développement de la végétation de palmiers à huile. Cette étude fournit des preuves que l'expansion des plantations de palmiers à huile et d'autres cultures commerciales entraîne des changements dans les variables biophysiques, réchauffant la surface du sol et augmentant ainsi l'augmentation de la température de l'air à cause du changement climatique. En utilisant des données Landsat à haute résolution, nous avons pu inclure les effets du changement d'utilisation des terres sur les variables biophysiques. Comprendre les effets du changement de la couverture terrestre sur les variables biophysiques peut soutenir des politiques concernant la conservation des forêts existantes, la planification et l'expansion des plantations de palmiers à huile et les mesures de boisement possibles. La connaissance des variables biophysiques, du bilan radiatif et de la répartition énergétique au cours du cycle de rotation du palmier à huile peut inclure de nouvelles pratiques de gestion susceptibles de réduire les conditions environnementales et microclimatiques extrêmes dans la phase initiale des plantations de palmiers à huile.

Paysages emblématiques des campagnes de l’Ouest, les bocages ont connu une série de transformations rapides et importantes ces quarante dernières années : érosion du linéaire de haies, changements des usages du sol, rationalisation et agrandissement du parcellaire, banalisation et massification des bâtiments agricoles, enfrichement des secteurs les plus difficiles à exploiter. L’ampleur des ajustements observés souligne le décalage entre ces formes paysagères héritées d’une longue histoire agraire, et l’évolution des systèmes agricoles qui contribuent à les produire.Si la transformation des paysages de bocage est généralement attribuée au tournant « productiviste » du modèle agricole français, les processus socio-techniques à l’origine de ces évolutions sont plus rarement explicités. L’objet de ce travail est d’évaluer plus spécifiquement la contribution de l’agrandissement des exploitations agricoles à la dynamique d’évolution des paysages bocagers de l’Ouest de la France.Ce travail de géographie s’appuie dans un premier temps sur une analyse statistique à l’échelle du grand Ouest de la France, visant à étudier l’effet des transformations foncières sur les structures spatiales agricoles (assolements, parcellaire, linéaires boisés…). Dans un second temps, les dynamiques paysagères et foncières de quatre espaces d’étude (Bessin, Bocage Virois, Sud Manche, Pays d’Auge), situés en domaine laitier et bocager mais présentant des configurations agricoles variées, ont été étudiées entre 2003 et 2016. Ce travail s’appuie notamment sur un dispositif méthodologique original, articulant au sein d’un système d’information géographique à échelle parcellaire (1) la construction d’un suivi à échelle spatio-temporelle fine des dynamiques paysagères (évolution du maillage bocager, de la trame parcellaire et de l’occupation du sol) et (2) la reconstitution de l’évolution de la mosaïque des parcellaires d’exploitations par appariement de plusieurs millésimes du registre parcellaire graphique. L’exploitation de cette base de données spatio-temporelle a permis de mieux comprendre le rôle de la transformation foncière des exploitations agricoles dans la dynamique des paysages bocagers. Enfin, une enquête de terrain a été réalisée auprès de 150 agriculteurs équitablement répartis dans les quatre espaces d’étude, afin d’appréhender les conséquences sociales, techniques et productives de l’agrandissement à l’échelle des exploitations agricoles, qui diffèrent singulièrement selon le type de trajectoire foncière suivie. / Symbolic landscapes of the countryside of the West of France, the bocage landscapes have undergone a series of transformations these last forty years : decrease in hedgerow density, land uses changes, plots extension, normalization and enlargement of farm buildings, spatial extension of wilderness… The intensity of landscape transformations highlights the contradiction between these landscape forms produced by a long agrarian history and the contemporary evolutions of farming systems. The transformation of hedgerow landscapes is generally attributed to the "productivist" turn of the French agricultural model. However, the socio-technical processes behind these changes are more rarely explained.The first purpose of this geography work is to study the effects of changing agricultural systems on agricultural spatial structures, based on a statistical analysis at the scale of the West of France. In a second step, the landscape and land dynamics of four study areas (Bessin, Bocage Virois, Sud Manche, Pays d'Auge), located in the dairy and bocage domain, have been studied between 2003 and 2016. This work is based on an original methodological device, set up in a geographical information system. This structuration of geographic information makes possible to (1) monitor the landscape dynamics (evolution of the hedgerow density, land cover and plot morphology changes) at a fine spatial and temporal scale and (2) to reconstruct the evolution of the mosaic of farm plots, by matching land-parcell identification systems across the time (2007, 2011, 2013). From this spatio-temporal database, we characterized the coevolution of landscape structures and farm territories across the time, in order to better understand the landscape consequences of farm enlargment.Finally, a field survey was carried out among 150 farmers equitably distributed in the four study areas, in order to apprehend the social, technical and productive consequences of the farms enlargment, which differ singularly according to the type of land trajectory followed.

Land surfaces have changed as a result of human and natural processes, such asdeforestation, urbanization, desertification and natural disasters like wildfires. Land use and landcover change impacts local and regional climates through various bio geophysical processes acrossmany time scales. More realistic representation of land surface parameters within the land surfacemodels are essential to for climate models to accurately simulate the effects of past, current andfuture land surface processes. In this study, we evaluated the sensitivity and accuracy of theWeather Research and Forecasting (WRF) model though the default MODIS land cover data andannually updated land cover data over southeast of United States. Findings of this study indicatedthat the land surface fluxes, and moisture simulations are more sensitive to the surfacecharacteristics over the southeast US. Consequently, we evaluated the WRF temperature andprecipitation simulations with more accurate observations of land surface parameters over thestudy area. We evaluate the model performance for the default and updated land cover simulationsagainst observational datasets. Results of the study showed that updating land cover resulted insubstantial variations in surface heat fluxes and moisture balances. Despite updated land use andland cover data provided more representative land surface characteristics, the WRF simulated 2- m temperature and precipitation did not improved due to use of updated land cover data. Further,we conducted machine learning experiments to post-process the Noah-MP land surface modelsimulations to determine if post processing the model outputs can improve the land surfaceparameters. The results indicate that the Noah-MP simulations using machine learning remarkablyimproved simulation accuracy and gradient boosting, and random forest model had smaller meanerror bias values and larger coefficient of determination over the majority of stations. Moreover,the findings of the current study showed that the accuracy of surface heat flux simulations byNoah-MP are influenced by land cover and vegetation type.

<p>The purpose of this thesis is to analyse interactions between freshwater flows, terrestrial ecosystems and human well-being. Freshwater management and policy has mainly focused on the liquid water part (surface and ground water run off) of the hydrological cycle including aquatic ecosystems. Although of great significance, this thesis shows that such a focus will not be sufficient for coping with freshwater related social-ecological vulnerability. The thesis illustrates that the terrestrial component of the hydrological cycle, reflected in vapour flows (or evapotranspiration), serves multiple functions in the human life-support system. A broader understanding of the interactions between terrestrial systems and freshwater flows is particularly important in light of present widespread land cover change in terrestrial ecosystems. </p><p>The water vapour flows from continental ecosystems were quantified at a global scale in Paper I of the thesis. It was estimated that in order to sustain the majority of global terrestrial ecosystem services on which humanity depends, an annual water vapour flow of 63 000 km3/yr is needed, including 6800 km3/yr for crop production. In comparison, the annual human withdrawal of liquid water amounts to roughly 4000 km3/yr. A potential conflict between freshwater for future food production and for terrestrial ecosystem services was identified. </p><p>Human redistribution of water vapour flows as a consequence of long-term land cover change was addressed at both continental (Australia) (Paper II) and global scales (Paper III). It was estimated that the annual vapour flow had decreased by 10% in Australia during the last 200 years. This is due to a decrease in woody vegetation for agricultural production. The reduction in vapour flows has caused severe problems with salinity of soils and rivers. The human-induced alteration of vapour flows was estimated at more than 15 times the volume of human-induced change in liquid water (Paper II). </p>

Orientador: Thiago Sanna Freire Silva / Resumo: As paisagens são a expressão da interação dinâmica entre processos naturais e atividades humanas. A região do Litoral Norte do Estado de São Paulo apresenta uma grande diversidade de fitofisionomias do bioma Mata Atlântica, e um rico patrimônio material e imaterial, em função da histórica interação do homem com a natureza. São inúmeros os vetores que agem simultaneamente sobre essa paisagem, resultando em efeitos cumulativos que transformam sua multifuncionalidade e multidimensionalidade. Este estudo objetivou a compreensão dos vetores de mudanças na paisagem do Litoral Norte do Estado de São Paulo. A transformação histórica da paisagem na área de estudo foi investigada buscando compreender a modificações dos cenários paisagísticos na sua integridade desde o início da colonização europeia na região de estudo. Através desta revisão histórica, demonstramos que a política econômica impulsionou investimentos em instalações tecnológicas e de acesso a região, que influenciaram no aumento das taxas de crescimento populacional, resultando num rápido crescimento das áreas urbanas após meados do século XX. O segundo capítulo quantificou as mudanças físicas da paisagem, através de séries históricas de imagens da série de satélites Landsat, utilizando o algoritmo Random Forests para classificação supervisionada do uso e cobertura da terra. Pudemos então, demonstrar que a região apresenta tendência a uma dicotomia no uso da terra, entre o uso urbano e a conservação ambiental. Entre 1985 e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Landscapes are an expression of the dynamic interaction between natural environments and human activities. The Northern Coast of São Paulo State has a high diversity of Atlantic Forest vegetation types, and the Serra do Mar mountain range has a rich material and immaterial heritage due to ancient human-nature interactions. There are several different driving forces of change acting together over these landscapes, resulting in a cumulative effect over time. Our study sought to understand the causes and consequences of landscape change in the Northern Coast of São Paulo state, from 1985 to present. We described the land use history and landscape changes since the Europeans arrived in the region, during the XVI century. We identified that national economic policies and interests have led to investment in improved access and technological development, which in turn influenced migration to the region and resulted in fast urban expansion. In the second chapter, we have shown that land use change in the Northern Coast of São Paulo poses a dichotomy between two main land cover change trajectories over 30 years: forest persistence and fast urban growth. We found only 100 km² (8%) of forest disturbance within the State Parks, while dense urban settlements grew 167% outside the park, replacing mainly rural land uses. To identify and understand the driving forces of change in the region, we used Partial Least Squares - Path Modelling to model the relation between driving forces and lands... (Complete abstract click electronic access below) / Doutor

The purpose of this thesis is to analyse interactions between freshwater flows, terrestrial ecosystems and human well-being. Freshwater management and policy has mainly focused on the liquid water part (surface and ground water run off) of the hydrological cycle including aquatic ecosystems. Although of great significance, this thesis shows that such a focus will not be sufficient for coping with freshwater related social-ecological vulnerability. The thesis illustrates that the terrestrial component of the hydrological cycle, reflected in vapour flows (or evapotranspiration), serves multiple functions in the human life-support system. A broader understanding of the interactions between terrestrial systems and freshwater flows is particularly important in light of present widespread land cover change in terrestrial ecosystems. The water vapour flows from continental ecosystems were quantified at a global scale in Paper I of the thesis. It was estimated that in order to sustain the majority of global terrestrial ecosystem services on which humanity depends, an annual water vapour flow of 63 000 km3/yr is needed, including 6800 km3/yr for crop production. In comparison, the annual human withdrawal of liquid water amounts to roughly 4000 km3/yr. A potential conflict between freshwater for future food production and for terrestrial ecosystem services was identified. Human redistribution of water vapour flows as a consequence of long-term land cover change was addressed at both continental (Australia) (Paper II) and global scales (Paper III). It was estimated that the annual vapour flow had decreased by 10% in Australia during the last 200 years. This is due to a decrease in woody vegetation for agricultural production. The reduction in vapour flows has caused severe problems with salinity of soils and rivers. The human-induced alteration of vapour flows was estimated at more than 15 times the volume of human-induced change in liquid water (Paper II).