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Tidal wetlands are expected to respond dynamically to global environmental change, but the extent to which wetland losses have been offset by gains remains poorly understood. We developed a global analysis of satellite data to simultaneously monitor change in three highly interconnected intertidal ecosystem types-tidal flats, tidal marshes, and mangroves-from 1999 to 2019. Globally, 13,700 square kilometers of tidal wetlands have been lost, but these have been substantially offset by gains of 9700 km2, leading to a net change of -4000 km2 over two decades. We found that 27% of these losses and gains were associated with direct human activities such as conversion to agriculture and restoration of lost wetlands. All other changes were attributed to indirect drivers, including the effects of coastal processes and climate change.

The fore reef spur and groove (SaG) zone is an important, but poorly understood, zone of coral reefs. Spurs (parallel ridges of carbonate material), are separated by grooves (regularly spaced channels) to form a distinct finger-like pattern around the margins of coral reefs. Few studies have collected quantitative data in SaG systems and many questions remain about their formation and evolution. This thesis aims to describe the eco-morphodynamics of SaGs by establishing the interactions and feedbacks between their geomorphology (form), hydrodynamics (function) and reef growth (evolution) across multiple spatial and temporal scales at reefs in the Indo-Pacific. This constitutes the most extensive and comprehensive study of SaG features to date. A remote sensing analysis of SaG morphometrics at 17 reefs in the southern Great Barrier Reef (GBR), Australia, revealed exposure to wave energy was the most important factor influencing SaG morphology with fore reef slope playing a secondary role. Four statistically distinct classes of SaG were also identified and described. In-situ hydrodynamic data from SaG zones at One Tree Reef, in the GBR and Moorea in French Polynesia showed that the fore reef SaG zone is a remarkably effective breakwater, dissipating up to 86% of wave energy. Currents in the zone were complex and variable. A unique suite of 38 cores from SaG zones at One Tree and Heron Reefs (in the southern GBR) and Moorea were combined with existing reef platform cores to identify three potential modes of fore reef and reef flat evolution. These modes were matched to the remote sensing defined classes, suggesting that remotely sensed data can provide insight into SaG evolution and potentially upscale the findings of in-situ hydrodynamic and reef growth studies. While further research is required, by studying multiple sites on multiple reefs this study provides globally applicable insights into SaG eco-morphodynamics across a broad spectrum of environmental conditions.

This document addresses the need for explicit inclusion of livelihoods within the environment nexus (water-energy-food security), not only responding to literature gaps but also addressing emerging dialogue from existing nexus consortia. We present the first conceptualization of ‘environmental livelihood security’, which combines the nexus perspective with sustainable livelihoods. The geographical focus of this paper is Southeast Asia and Oceania, a region currently wrought by the impacts of a changing climate. Climate change is the primary external forcing mechanism on the environmental livelihood security of communities in Southeast Asia and Oceania which, therefore, forms the applied crux of this paper. Finally, we provide a primer for using geospatial information to develop a spatial framework to enable geographical assessment of environmental livelihood security across the region. We conclude by linking the value of this research to ongoing sustainable development discussions, and for influencing policy agendas

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies. The categorization and conceptualization of geographic features is fundamental to cartography, geographic information retrieval, routing applications, spatial decision support and data sharing in general. However, there is no standard conceptualization of the world. Humans conceptualize features based on numerous factors including cultural background, knowledge, motivation and particularly space and time. Thus, geographic features are prone to multiple, context-dependent conceptualizations reflecting local conditions. This creates semantic heterogeneity and undermines interoperability. Standardization of a shared definition is often employed to overcome semantic heterogeneity. However, this approach loses important local diversity in feature conceptualizations and may result in feature definitions which are too broad or too specific. This work proposes the use of microtheories in Spatial Data Infrastructures, such as INSPIRE, to account for diversity of local conceptualizations while maintaining interoperability at a global level. It introduces a novel method of structuring microtheories based on space and time, represented by administrative boundaries, to reflect variations in feature conceptualization. A bottom-up approach, based on non-standard inference, is used to create an appropriate global-level feature definition from the local definitions. Conceptualizations of rivers, forests and estuaries throughout Europe are used to demonstrate how the approach can improve the INSPIRE data model and ease its adoption by European member states.