Advancing the Science Around Indirect and Seasonal Fish HabitatLaura 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 FindingsWipfli (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 100-2000 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 (cm3) 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 Influence of HDFs on Downstream Fish Downstream Fish

ProductivityProductivity

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 expectedSeptember 2011

Seasonal Fish Habitat

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Adults Juveniles Adults Juveniles Adults Juveniles Adults Juveniles Adults Juveniles

April/May Early June Late June Early July Late July

Season

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Fis

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aptu

red

Ephemeral

Intermittent

Perennial

Seasonal Fish Habitat - TRCA

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April and May Early June Late June Early July Late July

Season

Fis

h A

bu

nd

ance

Pumpkinseed

Blacknose dace

Brook Stickleback

Rock bass

Central mudminnow

Brook Trout

Creek Chub

Fathead minnow

Nothern redbelly dace

Cyprinidae

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 www.trca.on.ca/understand/headwater-study.dot

For More Information:For More Information:

AcknowledgementsLake Simcoe Clean Up FundThe Oak Ridges Moraine FoundationRegional Municipality of Peel Regional Municipality of YorkUniversity of WaterlooRideau Valley Conservation AuthorityCredit Valley ConservationHalton ConservationLake Simcoe and Region Conservation AuthorityAusable Bayfield Conservation AuthorityUpper Thames Region Conservation AuthorityMinistry of Natural ResourcesFisheries and Oceans CanadaGreat Lakes Sustainability FundToronto Remedial Action PlanOntario Headwater Institute and Ontario Trillium FundSouthern Ontario Stream Monitoring and Research Team (formerly Lake Ontario Modeling Team)Consultants: Cam Portt, George Coker, Paul Villard, and Derek ColemanMany dedicated field crews and volunteers