Ecosystem services are the varied goods and benefits provided by ecosystems that make human life possible. This concept has fostered scientific explorations of the services that nature provides to people with the goal of sustaining those services for future generations. As the world becomes increasingly urban, ecosystems are reshaped, and services are degraded. Provisioning and regulating ecosystem services, landscape planning, decision making, and agricultural systems and technologies play a distinctive role in feeding and sustaining the expanding urban population. Hence, the integrated assessment of these coupled components is necessary to understand food security and sustainable development. Nevertheless, frameworks that incorporate ecosystem services, urbanization, and human wellbeing are still scarce due to several conceptual and methodological gaps that challenge this assessment. As a consequence, these frameworks are not operationalized, and ecosystem services rarely receive proper attention in decision making. This dissertation seeks to improve our understanding of the role of ecosystem services at the landscape level and provides an approach for operationalizing decisions that affect sustainable practices and human wellbeing.

Evapotranspiration (ET) is an essential component of water cycle as it is an interlinkage between atmosphere, vegetation and soil surface in terms of energy and water balance. However, whether potential ET has the same tendency to change as actual ET and how ET trend (based on the difference between precipitation and runoff) is directly driven by dominant meteorological factors alone or combined with ecosystem‘s feedbacks to climate change (like land-use change) is still under the discussion. In this report, five ET parameterizations within two rainfall-runoff models [Coupled Heat and Mass Transfer Model (CoupModel) and Hydrologiska Byråns Vattenbalansavdelning (HBV)] have been set up based on six subcatchments of Sweden. The scenario derived from CoupModel shows that the trend of ET is affected by the change of land-use, where soil evaporation tends to shift to transpiration and interception evaporation. However, HBV model produces the other scenario: the trend of ET is merely the consequence of meteorological factors. Increased ET is contributed by increased interception evaporation due to the increased precipitation. After identifying the time split of changing ET trends, a dynamic simulation constructed both from HBV and CoupModel indicate that the increased total ET is primarily from increased ET in winter time. More and more interceptive water loss and transpiration resulted from land-use change due to more vegetation. On the other hand, land-use change is also a feed back to climate change. Transpiration controlled by the mechanism of stomata and water uptake controlled by reduction of soil moisture is highly related to variations of climatic conditions.

Au titre de ses engagements, la France doit comptabiliser annuellement les changements d'occupation du sol et les flux de carbone associés. Cet inventaire, réalisé par le Citepa, est délicat à évaluer, car les données sources sont complexes et contradictoires. En outre, ce secteur présente des enjeux stratégiques dans la lutte contre le changement climatique. Les limites de cet inventaire sont de plusieurs ordres : données sources imparfaites ; manque de connaissance sur les autres données existantes pouvant être utilisées; incertitude mal évaluée ; nécessité de validation de la pertinence des dynamiques estimées.L'objectif de cette thèse est d'analyser et d'évaluer les données sources (actuelles et potentielles) des matrices de changements d'occupation du sol afin d'améliorer la robustesse de l'inventaire. Il s'agit d'expertiser par une démarche scientifique la pertinence de l'inventaire. En particulier, il s'agit de comprendre les causes des incertitudes des données sources ; compiler les données disponibles et leurs métadonnées ; étudier qualitativement les dynamiques paysagères; et redéfinir un cadre méthodologique permettant d'estimer des taux de changements plus pertinents. Les résultats de ces travaux montrent que les niveaux de résolutions spatiales, thématiques et temporelles les plus précis entraînent la détection de faux positifs : la pertinence est à préférer à la précision, et les effets de dépendance d'échelle doivent être pris en compte. La thèse propose enfin un cadre d'interopérabilité afin d'intégrer des données hétérogènes au sein d'un nouveau protocole de modélisation alliant rééstimation des changements et allocation spatiale. / France is required to account for annual land-cover changes and induced carbon fluxes). This inventory is difficult to calcula te, for data source are complex and contradictory. Moreover, this sector is important as its role in combating climate change is emphasized. This thesis proposes improvements to several identified methodological issues: imperfect data sources, Jack of knowledge about other potential sources„ poorly evaluated uncertainties, validation of landscape dynamics consistency..Thus, the objective of this thesis is to analyse and assess current and potential data sources for computing land-cover change area matrixes, in order to enhance the robustness of the inventory. A scientific approach is conducted to assess the inventory, to understand what causes uncertainties in land cover products, to compile datasets and their metadata, to study the landscape dynamics, and to define a new methodological framework allowing better and more consistent estimates of land cover change rates at national scale.This work suggests that the finest spatial, thematical and temporal resolution levels lead to overestimation of false positives. Accuracy and consistency are preferable to precision and scale dependency must be considered. Finally, we propose an interoperability framework for data integration, via a modeling protocol linking land cover change estimation and spatial allocation.

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ABSTRACT SPATIAL AND TEMPORAL DYNAMICS OF LAND USE IMPACTS ON WATER QUALITY IN WATERSHED SYSTEMS SEPTEMBER 2007 OLGA TSVETKOVA, B.S., NOVGOROD STATE UNIVERSITY, RUSSIA M.S., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Timothy O. Randhir Predicting land use change and assessing watershed tradeoffs between the watershed system components through system simulation helps to determine future nutrient and sediment load reductions needed to obtain a particular water quality standard. This also helps to examine the tradeoffs among nutrient and sediment load reductions that achieve the same water quality objective. Tradeoff assessment is a useful tool to meet agricultural and urban needs in regard protecting water quality. The purpose of this study has been to develop and apply a spatial temporal dynamic simulation model for the land use change and a hydrologic dynamic simulation model for the estimation of the tradeoffs relationships between watershed contaminants and attributes. The Spatial – temporal dynamic model is applied to one of the subbasins within the Blackstone River Watershed to predict potential land use changes in the subbasin. Results show that the increase in urban land use in the watershed is associated with the decline in agricultural and forest land. The overall preliminary results show that urbanization could become a serious problem in the future. The results emphasize the need to protect agricultural area in rapidly changing watersheds. In the watershed tradeoffs simulation modeling, the effect of land use change on water quality is simulated using the Soil and Water Assessment Tool. The methodology is applied to the Blackstone River watershed and its 115 subbasins. Regression statistics as well as graphical techniques are used for accurate evaluation of the model. Water quality and quantity estimated using an array of equations to simulate watershed processes. It is observed that a fairly high variability exists for soluble phosphorus, mineral phosphorus, and sediment yield. The tradeoff relationships between watershed components are described by tradeoff equations and graphically. The regression results indicate that the highest correlations exist between nitrate and surface runoff and between mineral phosphorus and sediment yield. The final tradeoff matrix is developed for the study watershed and could be used to assess various policies that include policies on nutrients, water resources, and land use.

Global change profoundly alters biological communities and increases species extinction rates. Recent reports show that odonate species (dragonflies and damselflies) are declining globally, however, odonates can also respond strongly to climate and land use change through shifts in range and phenology - i.e., the timing of life history events. Understanding how and when species respond to rapid environmental change is critical to address conservation risks in a timely way. I assembled a dataset of ~2 million odonate records between 1901 and 2021 and investigated a series of research questions about odonate persistence within historically occupied regions, how species respond across continents, and mechanisms leading to these responses. I discovered that non-target effects of pesticides interacted with temperature increases, leading to higher rates of odonate declines across the United States. Species with greater capacities in shifting their range northward may be more robust to impacts of global change (Chapter 2). Converging across Europe and North America, stronger range limit shifts were associated with stronger shifts in emergence phenology towards earlier spring dates, even though land use histories are highly divergent among regions. It is temperature variability and range geography, determinants of habitat conditions to which species are exposed, rather than ecological traits, that facilitated or hindered range shifts (Chapter 3). Temperature variability interacted with pesticide applications to hinder persistence or establishment in new areas that were otherwise climatically suitable, providing further evidence of impacts of extreme weather to insect declines. Tests of methods commonly used to predict species' distributions under future climate change (Species Distribution Models) revealed that species most likely to decline were also less likely to be well modeled, in terms of their temporal transferability (Chapter 4). This work deepens knowledge of spatial and temporal interspecific variation in species distributions as humans continue to reshape the Earth's ecosystems and climatic processes. This thesis can help improve species-specific conservation planning for species that decline in the face of anthropogenic activities.

Empirically based lumped hydrologic models have an extensive track record of use where as physically based, multi-dimensional distributed models are evolving for various engineering applications. Despite the availability of high resolution data, better computational resources and robust numerical methods, the usage of distributed models is still limited. The purpose of this research is to establish the credibility and usability of distributed hydrologic modeling tools of the United States Army Corps of Engineers (USACE) in order to promote the extended use of distributed models. Two of the USACE models were used as the modeling tools for the study, with Gridded Surface and Subsurface Hydrologic Analysis (GSSHA) representing a distributed and with Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) representing a lumped model. Watershed Modeling System (WMS) was used as the pre- and post-processing tool. The credibility of distributed models has been established by validating that the distributed models are efficient in solving complex hydrologic problems. The distributed and lumped models in HEC-HMS were compared. Similarly, the capabilities of GSSHA and lumped models in HEC-HMS in simulating land use change scenario were compared. The results of these studies were published in peer-reviewed journals. Similarly, the usability of the distributed models was studied taking GSSHA-WMS modeling as a test case. Some of the major issues in GSSHA-modeling using WMS interface were investigated and solutions were proposed to solve such issues. Personal experience with GSSHA and feedback from the students in a graduate class (CE531) and from participants in the USACE GSSHA training course were used to identify such roadblocks. The project being partly funded by the USACE Engineering Research and Development Center (ERDC) and partly by Aquaveo LLC, the research was motivated in improving GSSHA modeling using the WMS interface.

The Western Cape (South Africa) recently witnessed the most severe drought on record. The meteorological drought, which was characterised by below-normal rainfall for three consecutive years (2015 – 2017), cascaded to agricultural and then hydrological drought, resulting in devastating socio-economic consequences. While some studies indicate that climate change may increase the severity and frequency of droughts in the Western Cape in the future, there is a lack of information on how to mitigate the effects of future climate change on hydrological drought. This dissertation therefore investigated the extent to which land-use changes could be applied to reduce climate change impacts on future hydrological drought in this region. For the study, the revised Soil Water Assessment Tool (SWAT+) was calibrated and evaluated over four river basins in the Western Cape, and the climate simulation dataset from the COordinated Regional Downscaling EXperiment (CORDEX) was bias-corrected. Using the bias-corrected climate data as a forcing, the SWAT+ was used to project the impacts of future climate change on water yield and hydrological drought in the four basins and to quantify the sensitivity of the projection to four feasible land-use change scenarios in these basins. The relevant land-use scenarios are the expansion of mixed forests (FrLand), the restoration of grassland (GrLand), the restoration of shrubland (SrLand), and the expansion of cropland (CrLand). The model evaluation shows good agreement between the simulated and observed monthly streamflow at hydrological stations, and the bias correction of the CORDEX datasets improved the quality of the SWAT+ hydrological simulations in the four basins. The climate change projection depicts an increase in temperature and potential evapotranspiration but a decrease in precipitation and all the hydrological variables. Drying is projected across the Western Cape, and the magnitude of such drying increases with higher global warming levels (GWLs). The land-use changes alter the impacts of climate change by influencing the hydrological balance. While FrLand mitigates the impacts of climate change on the frequency of hydrological drought by increasing streamflow, soil water and percolation, CrLand mitigates the impacts by increasing surface runoff. However, the magnitudes of these land-use change impacts are very small compared to the climate change impacts. Hence, the results suggest that land-use changes may not be an efficient strategy for mitigating the climate change impacts on hydrological drought over the region. The findings obtained from this 2 research provide relevant information towards mitigating the severity of future droughts and improving water security in Western Cape River Basins.

Climate change and human activities alter the hydrologic systems and exerted global scale impacts on our environment with significant implications for water resources. Climate change can be characterized by the change of precipitation and temperature, and both precipitation pattern change and global warming are associated with the increase in frequency of flooding or drought and low flows. With increasing water demand from domestic, agricultural, commercial, and industrial sectors, humans are increasingly becoming a significant component of the hydrologic cycle. Human activities have transformed hydrologic processes at spatial scales ranging from local to global. Human activities affecting watershed hydrology include land use change, dam construction and reservoir operation, groundwater pumping, surface water withdrawal, irrigation, return flow, and others. In this thesis, the hydromorphology (i.e., the change of coupled hydrologic and human systems) of the Econlockhatchee River (Econ River for short) is studied. Due to the growth of the Orlando metropolitan area the Econ basin has been substantially urbanized with drastic change of the land cover. The land use / land cover change from 1940s to 2000s has been quantified by compiling existing land cover data and digitizing aerial photography images. Rainfall data have been analyzed to determine the extent that climate change has affected the river flow compared to land use change. The changes in stream flow at the annual scale and low flows are analyzed. The Econ River has experienced minimal changes in the amount of annual streamflow but significant changes to the amount of low flows. These changes are due to urbanization and other human interferences.

Long-term hydrologic and nonpoint source (NPS) pollutant response is quantified for four headwater basins of the Occoquan River in northern Virginia using 24 years of observed rainfall, basin discharge, water chemistry, and derived land use/land cover (LULC) data. Long-term summaries document that several hydrologic and NPS pollutant delivery characteristics in the urbanizing Cub Run basin are significantly different from adjacent non-urban basins. Higher annual NPS fluxes of total suspended solids (TSS), phosphorus (P), and nitrogen (N) in Cub Run are identified with periods of increased soil disturbance from urban land development and significantly increased storm volumes resulting from higher mean impervious cover. Long-term summaries of nutrient flux are consistent with literature documenting increased ratios of particulate to soluble nutrients with increased discharge. Storm fluxes of NPS particulate P, soluble P, particulate N, and soluble N make up 92, 67, 89, and 50 percent, respectively, of total NPS nutrient fluxes from all headwater basins, with between 88 and 98 percent of mean annual TSS fluxes delivered by storm flow. Higher sediment and nutrient fluxes observed in Cub Run basin during the summer and fall growing season after 1983 demonstrate the impact of replacing vegetated cover with urban impervious surface (IS). Annual regression models indicate that mean IS above 10 percent and precipitation are significantly associated with total basin discharge (r2=0.65). The positive association of annual storm soluble phosphorus flux with cumulative mean IS suggests the need for continued evaluation of urban NPS soluble phosphorus strategies. Urban soil disturbance is indicated by measuring the annual change in mean IS (delta IS). Regression models show that urban soil disturbance is a significant source of TSS flux in all seasons. Long-term total soluble phosphorus and nitrogen fluxes are significantly and positively associated with precipitation, delta IS, and agricultural land use (r2=0.50 and 0.58, respectively). The significant impact of urbanization on hydrologic and NPS pollutant flux, especially during the growing season, is a major finding of this study. / Ph. D.