Organic matter, in its various forms, is thought to be important for the ecological functioning of large lowland river systems. During periods of low flow, organic material accumulates on the floodplain and other in-channel surfaces and this material then provides a potential energy source for riverine food webs when it enters the river during flooding. Variations in the type and amount of this organic material may therefore have implications for aquatic food webs in Australian lowland river systems. In this paper we consider spatial variations in organic matter content present on in-channel floodplain surfaces between different geomorphic settings along the Barwon-Darling River. In general, floodplain surfaces in wider, unconfined geomorphic settings were found to contain greater amounts of surface leaf litter and sediment organic matter than surfaces in more confined geomorphic settings, at both the valley trough scale (leaf litter-239.7g/m² ~ 93% greater; sediment organics-8.7% ~ 50% greater) and the channel cross-section scale (leaf litter- 17.8% greater; sediment organics- 10.4% greater), Across both valley trough and river channel conditions, floodplain surfaces higher in the bankfull channel contained on average, twice the amount of surface leaf litter (350.1 g/m² ±64.2) and sediment organic matter (10.1% ±1.3), than surfaces at lower elevations (Leaf litter-61.5g/m² ±16.5; sediment organics-4.9% ±0.7). This study suggests that large scale geomorphological conditions can influence organic matter accumulation on in-channel floodplain surfaces. Overbank flows occur relatively infrequently in large lowland river systems hence smaller in-channel pulses and the maintenance of in-channel geomorphic structures could also prove important to the ecological integrity of these systems.

While the immigration attitudes of those in societal and ethnic minority groups have been well documented, the attitudes of immigration activists on specific issues have seen little systematic study. This article reports the findings of surveys on US immigration and trade-liberalisation policy conducted with members of the civilian border-patrol Minuteman group, and border humanitarian groups such as Samaritans and No More Deaths. Previous surveys have found relatively high levels of support for the Minuteman effort in US border states. This study finds significant divergence on actual attitudes between such activists and non-activists, the majority of whom in both groups reside in Arizona, the border state with the highest reported traffic of unauthorised immigrants. Survey findings also suggest that the relationship between attitudes toward immigration and trade liberalisation is more complex than has been presumed. The specific provisions of liberalisation agreements, in particular those on labour and the environment, can play a major role in determining support for them, including support from those with strong attitudes on related issues such as immigration.

Previous episodes of sea-level rise, including during the Pleistocene, Holocene and recent past, offer a potential rich source of information to understand present sea-level behaviour and provide the basis to model possible future marine inundations resulting from climate changes. A response mechanism can be formulated, using this evidence from previous episodes of sea-level rise, to construct specific scenarios that may be projected using geographic information systems (GIS). Such palaeo-model projections can be evaluated against evidence from former higher Holocene shorelines and this approach is collectively termed the 'past-present-future' (PPF) methodology. This thesis considers the possibility of sea-level rise being oscillatory and how this may impact the formulation of future sea-level projections and the policy environment. Spectral analysis was undertaken on a range of sea-level records, temperature databases and other climate proxies in historical and Holocene records. A number of common periodicities were identified in both data sets (the recent and geological past), providing a basis to project past sea-level behaviour into the future. The existence of these common periodicities within a number of records suggests the presence of a complex rather than an exclusively linear response function as is currently assumed within climate models.