River flood plains are model ecosystems to test general hydrogeomorphic and ecological concepts

Abstract

A major challenge in ecology is to link patterns and processes across different spatial and temporal scales. Flood plains are ideal model ecosystems to study (i) the processes that create and maintain environmental heterogeneity and (ii) to quantify the effects of environmental heterogeneity on ecosystem functioning and biodiversity. Fluvial processes of cut-and-fill alluviation create new channels, bars and benches within a flood plain that in turn provides new surface for subsequent vegetative recruitment and growth resulting in a shifting mosaic of interconnected aquatic and terrestrial habitat patches. Composition and spatial arrangement of these habitat patches control the movement of organisms and matter among adjacent patches; and the capacity of a habitat to process matter depends on the productivity of adjacent patches and on the exchange among these patches. The exchange of matter and organisms among habitats of different age and productivity is often pulsed in nature. Small pulses of a physical driver (e.g. short-term increase in flow) can leach large amounts of nutrients thereby stimulating primary production in adjacent aquatic patches, or trigger mass emergence of aquatic insects that may in turn impact recipient terrestrial communities. Hence, biodiversity in a river corridor context is hierarchically structured and strongly linked to the dynamic biophysical processes and feedback mechanisms that drive these chronosequences over broad time and space scales. Today, the active conversion of degraded ecosystems back to a more heterogeneous and dynamic state has become an important aspect of restoration and management where maintaining or allowing a return to the shifting habitat mosaic dynamism is the goal with the expected outcome greater biodiversity and clean water among other valuable ecosystem goods and services.

Influence of hydrology on the fish body condition in a large subtropical floodplain

“…These areas contributed with new habitats; these in their stead provided new surface for subsequent vegetative recruitment and growth, and favoured the transport of food resources (nutrients and organic detritus) from the floodplain to the river. They also provided access for allochthonous resources and suspended sediments transported from the river to the floodplain (Tockner et al, 2010).…”

Multifunctional floodplain management and biodiversity effects: a knowledge synthesis for six European countries

“…MFM projects were selected according to their relevance for the study aims as judged by the national experts. To reach consistency among contributions for each country, we understand floodplains for this study as 'low-relief earth surfaces composed of fluvial deposits that are frequently flooded (active floodplains) or formerly flooded (morphological floodplains) and are an integral part of catchments' (Tockner et al 2010). Although the balanced provision of many functions and services should ideally be aimed for in MFM (Schindler et al 2014;Plieninger et al 2015), we further agreed to potentially consider bifunctional management Fig.…”

Urban Growth and Flood Disasters in the Coastal River Basin of South-Central Chile (1943–2011)

“…Floods are natural processes in river systems [1,2]; however, humans have occupied and urbanized floodplains for their urbanization attractiveness due to planar morphology and water availability [3,4]. The latter has translated into the growth of flood risk zones for human settlements and infrastructure due to a greater concentration of people and structures [5,6].…”