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)
Headwater basins act as
“hydrologically active
areas” becoming activated
during wet conditions and
are linked
hydrogeomporphic
components of the basin
(Gomi et al. 2002)
•
90% of a river’s flow may be derived
from catchment headwaters
(Saunders 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 100-2000
YOY salmonids
•Is this comparable to S.
Ontario?
Photo source: Wipfli (2005)
Organic Drift Study 2008
• 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!
Photo Credit: Odum Idika and Rachel Martens
Organic Drift Study 2008
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
Overall Findings…
• HDFs seem to be
important sources
of food for fish
– Indirect Fish
Habitat
• Cumulatively
important
• How much
material reaches
downstream?
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
Total Number of Fish Captured
Seasonal Fish Habitat - TRCA
250
Ephemeral
Intermittent
Perennial
200
150
100
50
0
Adults
Juveniles
April/May
Adults
Juveniles
Early June
Adults
Juveniles
Late June
Season
Adults
Juveniles
Early July
Adults
Juveniles
Late July
Fish Abundance
180
160
Pumpkinseed
140
Brook Stickleback
120
100
80
Blacknose dace
Rock bass
Central mudminnow
Brook Trout
Creek Chub
Fathead minnow
Nothern redbelly dace
Cyprinidae
60
40
20
0
April and May
Early June
Late June
Season
Early July
Late July
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
For More Information:
Headwater Webpage
www.trca.on.ca/understand/headwater-study.dot
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