School of Biological Sciences Seminar Series

Flood rhythms: Expansion and contraction of aquatic habitat in riverine landscapes

Speaker

Associate Professor Timothy D Jardine

Institute

School of Environment and Sustainability Toxicology Centre University of Saskatchewan Canada

Time & Place

Thu, 11 Apr 2019 12:00:00 NZST in Rehua 329

All are welcome

Abstract

Society often associates floods with death and destruction.  Yet floods can also be a replenishing force in ecosystems.  These “two faces of floods” can be reconciled in part by the predictability, or rhythmicity, of their arrival. Drawing on work in northern Australia and northern Canada, this presentation will show how floods that are predictable in timing and magnitude lead to adaptations that enhance biological productivity and diversity, and highlight the vectors that are responsible for transferring energy and organic matter from productive to unproductive habitats.  It will begin with work in Australia’s wet-dry tropics, where a large multi-disciplinary team examined seasonal inundation of savanna landscapes and showed how large-bodied organisms such as fishes and crocodiles capitalize on floods by exploiting prey from temporarily available habitats.  Next, it will consider the cold landscapes of the northern Great Plains, Canada, where geographically-isolated pothole wetlands freeze to the bottom in winter, mimicking a seasonal loss of liquid water that is common in warm dryland regions.  This seasonal “drying” causes massive seasonal fluxes of insects, namely water boatmen, to occur from wetlands into rivers and lakes where they are preyed upon by fishes, supporting fisheries in otherwise unproductive systems.  The presentation will close with a discussion of human threats to these ecosystem connections, including a proliferation of hydro dams in the developing world and a continuing drainage of seemingly unimportant wetlands in agricultural landscapes.

Introduced by Angus McIntosh