Landscape connectivity at stream

crossings in the Credit River watershed

CASIOPA AGM

April 9th 2015

Why Inventory Road-Stream Crossings?

• Valley systems are the backbone of many ecological

networks in agricultural and urban contexts

• Linear road system - multiple barriers across stream

network

• 36% of road crossings in the Great Lakes basin estimated

to be passable to fish (Januchowski-Hartley et al. 2013)

• Unknown movement potential for terrestrial species

Assessment Supports Multiple Goals

• Understanding natural heritage system connectivity

– Integrate terrestrial and aquatic assessments for connectivity

• Barrier priorities for restoration

• Mapping of intermittent streams

• Floodplain mapping updates

• Education

• Supports input to partners

• Input into Road EA Process

Questions

• Where is it important to mange connectivity across

the natural heritage system?

• May be different for aquatic and terrestrial species

• What measures should we be recording?

• What species are we mitigating impacts for?

• Can we create an integrated assessment of terrestrial

and aquatic connectivity?

Where?

Credit River Watershed Natural Heritage System

Components of the CRWNHS

Natural heritage features • Valleylands

• Wetlands

• Woodlands

• Aquatic habitat and Lake Ontario shorelines

• Significant wildlife habitat

• Habitat of endangered and threatened species

Buffers Buffers around natural heritage features to protect features and

their functions from adjoining land uses

Natural heritage areas • Centres for Biodiversity

Centres for Biodiversity

Issues at Road-Stream Crossings

Factors influencing Terrestrial Passage

Photo Credit: Dillon Consulting

Ltd. (Terry Fox Dr.) • Species biology

• Structure Height

• Openness Ratio

• Traffic Intensity

• Vegetation

Complexity

Factors influencing Aquatic Passage

• Species biology

• Stream velocity

• Height of jump and pool

depth

• Water Temp

• Stream depth

• Season/Time of Year

• Structure length, slope

– Availability/size of substrate

and resting areas

Methodology- Terrestrial & Aquatic Passage

Structure Description: Structure

information grouped from overlapping

sections from Terrestrial and Aquatic

components

- Structure type, use, dimensions

- Road surface, shoulder type, traffic

- Sketch/additional notes

Terrestrial Passage:

- Terrestrial Passage presence

- Evidence of wildlife use

- Road kill

(Source: Adapted from Road culvert classification Evaluation Form,

CLOCA)

Aquatic Passage: Presence/Absence of

potential passage issues, measurements of

perched/grade separations

(Source: Barrier Assessment, Aquatic Sciences & Restoration CVC)

Criteria Funneling/

Fencing

Likelihood of

Passage

• Height > 3.0 m and OR >0.6

• Terrestrial terrain is present along entire length of

culvert/bridge

Yes Very High (all wildlife)

• Height > 1.0 m and OR >0.25

• Terrestrial terrain is present along entire length of

culvert/bridge

Yes High (small mammals/herps)

• Height > 1.0 m and OR >0.1

• Terrestrial terrain is present along entire length of

culvert/bridge

Yes Moderate (small mammals)

• Height > 0.5 m and OR >0.25

• Terrestrial terrain is present along entire length of

culvert/bridge

Yes Moderate (herps)

• Barrier is a gravel road with a traffic volume of <3

cars/5min

No Moderate (low risk of mortality

from cars)

• Meets the requirements in criteria 1-4, but is not in a

defined valley or have funneling towards crossing

structure

No Low (suitable for some or all

species/ mortality risk)

• Any breaks in the habitat network where a structure

exists, but does not meet the criteria

No Low (not suitable for wildlife)

• Any breaks in the habitat network where there is no

crossing structure

No Low

Mock Evaluation

Terrestrial Passage

Evaluating Aquatic Passage

• Under development

Criteria Likelihood of Passage

No passage problem Very High

Barrier at high flows High

Some species and/or life stages cannot

pass at most stream flows

Moderate

Most species and life stages cannot pass at

most stream flows

Low

Adapted from Great Lakes Road Stream Crossing Assessment; US Fish & Wildlife Service

Mock Evaluation

Aquatic Passage

Combining The Results

Next Steps

• Consult & finalize criteria with terrestrial

and aquatic staff

• Review how results impact connectivity

across the Natural Heritage System

• Cross reference with circuitscape model –

Important areas for connectivity

Acknowledgements

• TRCA

• CLOCA

• Conservation Halton

• Ontario Stream Assessment

Protocol

• Great Lakes Road Stream

Crossing Inventory (US Fish &

Wildlife)

• River and Stream continuity

project (streamcontinuity.org)

For more information or to provide input please contact:

Yvette Roy – Ecologist - Landscape Science

yroy@creditvalleyca.ca

• Katie MacDonnell

• Phil Bird

• Jon Clayton

• Heather Lynn

• CVC restoration and

stewardship staff

Thank-you

Evidence of Wildlife Use

Other