Advancing the Science Around Indirect and Seasonal Fish Habitat Laura C.R. Del Giudice, Senior Planning Ecologist, B.Sc., M.F.C.

Vulnerability of Headwaters Historic Data Source: McGill University

What is a Headwater Drainage Feature (HDF)?

Examples of Headwater Drainage Features

Literature Review Completed in March 2007 to examine the state of the science with respect to the natural functions of temporary streams Examined all potential functions that HDFs may have Majority of the headwater literature focused on permanently-flowing features Very few papers discussed intermittent or ephemeral systems, and most ephemeral systems were located in arid or semi-arid settings

Sound bites from the Literature Headwater Streams constitute >50 to 80% of the length of rivers (Schlosser 1982) 90% of a river’s flow may be derived from catchment headwaters (Saunders et al. 2002) Headwater basins act as “hydrologically active areas” becoming activated during wet conditions and are linked hydrogeomporphic components of the basin (Gomi et al. 2002) The spatial extent of headwaters can account for 70-80% of the total catchment area within a watershed (Gomi et al. 2002)

Literature Review Findings Wipfli (2005) Examined organic drift from fishless headwater streams in forested mountainous terrain in Alaska Streams were permanently flowing but had minimal flow at certain times of the year Found that small streams contributed enough organic materials to support YOY salmonids Is this comparable to S. Ontario? Photo source: Wipfli (2005)

Organic Drift Study 2008 Photo Credit: Odum Idika and Rachel Martens Replicate study from Alaska by Wipfli (2005) in S. Ontario Partnered with University of Waterloo – Odum Idika and Dr. David Barton Examined forested and agricultural HDFs Examined 16 HDFs, 13 ephemeral and 3 intermittent sites throughout the GTA Sampling occurred after rain events – a wet year!

Mean Number of Invertebrates Collected per Event Organic Drift Study 2008

Mean Volume of Invertebrates (cm 3 ) Collected per Event Organic Drift Study 2008

Mean Amount (g) of Plant Matter Collected per Event Organic Drift Study 2008

HDFs seem to be important sources of food for fish – Indirect Fish Habitat Cumulatively important How much material reaches downstream? Overall Findings… Organic Drift Study 2008

Influence of HDFs on Downstream Fish Productivity

Study Design Compare stomach contents of fish sampled from pools within main branch streams downstream of HDF to a control upstream Sites located across the GTA with forested, agricultural, and urban sites Sampling occurred during baseflow and high flow events Data collection complete, thesis expected September 2011

Seasonal Fish Habitat

Seasonal Fish Habitat - TRCA

Take Home Messages… Headwater drainage features: are highly variable with regard to flow and contributions appear to provide both indirect and direct (seasonal) fish habitat likely cannot be replicated by SWM ponds or storm sewers Need to protect functions Solutions?: Maintaining open channels and LID

Headwater Webpage For More Information:

Acknowledgements Lake Simcoe Clean Up Fund The Oak Ridges Moraine Foundation Regional Municipality of Peel Regional Municipality of York University of Waterloo Rideau Valley Conservation Authority Credit Valley Conservation Halton Conservation Lake Simcoe and Region Conservation Authority Ausable Bayfield Conservation Authority Upper Thames Region Conservation Authority Ministry of Natural Resources Fisheries and Oceans Canada Great Lakes Sustainability Fund Toronto Remedial Action Plan Ontario Headwater Institute and Ontario Trillium Fund Southern Ontario Stream Monitoring and Research Team (formerly Lake Ontario Modeling Team) Consultants: Cam Portt, George Coker, Paul Villard, and Derek Coleman Many dedicated field crews and volunteers