Lowland rivers: an Australian introduction

Despite the lack of a detailed definition of lowland rivers there are a number of ecosystem models that conceptualize their structure and function. The River Continuum Concept (RCC; Vannote et al., 1980) was initially applied but later criticized (Sedell et al., 1989) because of its inability to evaluate biotic assemblages in large rivers and metabolic interactions in ecosystems and its emphasis on longitudinal linkages rather than lateral transfers between the channel and floodplain. The Flood Pulse Concept (FPC; Junk et al., 1989) addresses this problem and concerns itself with the ecological significance of temporal patterns of flow in lowland rivers. It recognizes the importance of floods in the dynamics of river – flood-plain systems. However, this concept may be less applicable to confined lowland systems. The Riverine Productivity Model of Thorp and Delong (1994) concentrated on confined lowland systems and highlighted the significance of instream production and floodplain inputs of carbon in periods not just related to floods. Recently, Walker et al. (1995) have called for the development of a more generic model for dryland – lowland rivers. They suggest a more flexible approach that recognizes the importance of all energy transfers, and propose that a hybrid model could be formulated from the models and concepts already outlined.