title: Integrated conservation planning for river-wetland mosaics
Creators: name: E Souza Reis, Vanessa
Publisher: name: Griffith University
Year: 2018
Subjects: subject: Conservation
subject: River-wetland mosaics
subject: Floodplain river ecosystems
subject: Wetland hexagons
subject: Subcatchments
subject: Temporal dynamics

description: Wetlands are highly productive and biodiverse ecosystems and provide many ecosystem services for humans. They are a key component of the natural hydrological cycle and are involved in important biophysical processes, such as the exchange of sediments, nutrients and organisms which influence water quality and functional integrity of rivers. Owing to their high productivity, fertile soils, and importance for water provision, many of the world’s wetlands have a long history of human occupation and intensive use. As a consequence, extensive degradation and modification of wetland ecosystems by human activities has occurred worldwide. In seasonal wetlands, the timing and duration of soil saturation and inundation are the main determinants of geomorphological and ecological characteristics that give rise to a great variety of ecosystem types. Although the ecological functioning of seasonal wetlands relies on this strong temporal driver, wetland conservation decisions often are based on static maps of wetland boundaries that fail to depict their dynamic hydrological variability and connectivity. Another challenge in wetland conservation is accounting for multiple dimensions of wetland connectivity in the riverine landscape. For example, the ecological integrity of large floodplain rivers, such as the Amazon River system, depends on the maintenance of a diversity of waterbodies with variable degrees of connectivity between themselves and with the main river channel. Lack of adequate frameworks in wetland conservation planning to account for these different sources of connectivity can compromise the long-term persistence and integrity of wetlands in the landscape. This is a critical issue because human activities such as land use change, levee construction and flow regime alterations can lead to the disruption of connectivity, thus greatly affecting wetlands downstream and compromising their ecological integrity and provision of ecosystem services. The overall objective of this thesis is to develop a new framework of systematic conservation planning for river-floodplain ecosystems that adequately accounts for the multidimensional connectivity of wetlands in riverine landscapes. To achieve that, I have combined the use of remote sensing tools at multiple scales with statistical modelling and spatial planning to address three main issues in wetland conservation: (1) the lack of comprehensive assessments to determine conservation status of the world’s wetlands, (2) the limitations of representing wetland seasonality in traditional static maps that often delineate wetland boundaries based on minimum or maximum extents, and (3) the lack of adequate spatial frameworks in systematic conservation planning to deal with wetland connectivity in the riverine landscape. To address the first issue, I developed a global-scale portrait of the threats and protection status of the world’s inland wetlands. This was achieved by combining a global map of inundation extent derived from satellite images with data on threats from human influence and on protected areas. Inland wetlands represent only ~6% of the world’s land surface, and about 89% of these areas have no formal protection (as defined by protected areas IUCN I-VI and Ramsar sites). Wetland protection was variable across the world, ranging from 20% in Central and 18% in South America to only 8% in Asia. Particularly high human influence was found in Asia, which contains the largest wetland area of the world. High human influence was observed in wetlands even when they are within protected areas. This demonstrated that terrestrial protected areas do not always adequately protect wetland ecosystems and underscores the urgent need for more effective conservation measures worldwide. To tackle the second issue, I undertook a hydrological classification of the Amazon wetlands according to the timing and duration of inundation. The classification was based on remotely sensed monthly inundation maps, and also investigated how precipitation regimes affect wetland distribution and hydrological dynamics. Permanently inundated wetlands accounted for the largest area and were mainly floodplains located in the lowlands of the catchment. Seasonally inundated wetlands varied greatly in duration of inundation over the course of the year, ranging from one to nine months. Distinct seasonal timing was detected among large wetland complexes, reflecting rainfall regimes as well as time lags for recession and drying. For example, inundation in the extensive Llanos the Moxos region of the southern Amazon was protracted and lasted well after the rainy season, compared to the Roraima region of the northern Amazon where inundation was shorter and tracked the rainy season. This integration of inundation dynamics into wetland classification captures regional differences in timing and duration of inundation in major wetlands of the basin that should be considered in conservation planning and other ecological applications. Finally, I developed a new framework in systematic conservation planning to account for the multidimensional connectivity of floodplain river ecosystems and provide more adequate protection of wetlands, and applied this to the entire Amazon basin. Accounting for both within-floodplain and longitudinal river connectivity in the riverine landscape, the new spatial framework combines two types of planning units – wetland hexagons and subcatchments – which were connected using two distance-based approaches. Four prioritization scenarios were tested comparing only within-floodplain connectivity versus integrated within-floodplain and upstream connectivity and resulted in varying levels of reduced impact. When only considering within-floodplain connectivity, propagation of impacts from the surroundings and upstream catchment was ignored. In contrast, the scenario that included both within-floodplain and longitudinal river connectivity agglomerated subcatchments around the priority wetlands, achieving catchment integration that efficiently reduced impact. This thesis contributes to the field of wetland conservation by integrating cutting edge data science with novel planning methods. It highlights the conservation status of inland wetlands and quantifies global and continental threat patterns. The innovative classification approach that spatially represents seasonal patterns in wetland inundation can be used to explore the role of seasonality on the ecological characteristics and functions of different wetlands complexes. It represents an important step towards including temporal dynamics in wetland conservation planning and management. Furthermore, including the multidimensional connectivity of wetlands in a comprehensive spatial framework can offer more ecologically meaningful protection to floodplains. This is crucial to plan for safeguarding wetland ecosystem functions at the landscape context. Finally, the use of global remotely sensed data sets make all approaches presented here readily adaptable for use in other regions of the world.