Best Management Practices for Mitigating the Effects of Roads on Amphibian and Reptile Species ...

104 Pages·2016·5.59 MB·English

Best Management Practices
for Mitigating the Effects of Roads
on Amphibian and Reptile
Species at Risk in Ontario
April 2016
Written by Kari Gunson, David Seburn, Julia Kintsch and Joe Crowley
ontario.ca/speciesatrisk
1
Suggested Citation
Ontario Ministry of Natural Resources and Forestry. April 2016. Best Management Practices
for Mitigating the Effects of Roads on Amphibians and Reptile Species at Risk in Ontario.
Queen’s Printer for Ontario. 112 pp.
Acknowledgements
This document was written and reviewed by: to completion. Special thanks to the
K. Gunson, Eco-Kare International; D. Seburn, Ontario Ministry of Transportation (MTO)
Seburn Ecological Services; J. Kintsch, Eco- Environmental Policy Office for their review
Resolutions; and J. Crowley, Ontario Ministry of several draft versions of this document.
of Natural Resources and Forestry (MNRF). Many thanks to those that provided input
This document benefitted from reviews by on costs and other advisement from specific
MNRF SAR biologists and staff. Many thanks mitigation projects, namely Andrew Healy
to Trina Rytwinski for her contribution to the with Northeast Region MTO, and Rick Levick
Study Design and Road Impacts sections. with the Longpoint Causeway Improvement
Picture contributions and credits are denoted Committee. Kevin Williams with Atlantic
throughout the document. Thank you to Industries Limited provided expertise on
the MNRF Species at Risk Branch project engineering considerations for using culverts
management team (Joe Crowley, Darlene as wildlife crossing structures. This document
Dove, Amanda Eddington, Natasha Leahy, is meant to be a first edition within a cutting-
Megan McAndrew, Roxanne St. Martin, edge and fast evolving field of applied science.
Lara Griffin) for leading the project
Cover photo provided by Joe Crowley
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TABLE OF CONTENTS
1 INTRODUCTION ..............................................................................................................5
1.1 Purpose .........................................................................................................................5
1.2 Endangered Species Act, 2007 .....................................................................................5
1.3 Document Outline .........................................................................................................6
2 IMPACTS OF ROADS .....................................................................................................7
3 MITIGATION PLANNING ..............................................................................................8
3.1. Project-level Impact Avoidance and Mitigation ............................................................8
3.2 Project Planning Considerations and Sources of Information .......................................8
3.3 Recommended Process ...............................................................................................10
3.4 Landscape Considerations ..........................................................................................12
4 ROAD MITIGATION BMPS .........................................................................................13
4.1. Crossing Structures .....................................................................................................13
4.1.1 Types of Crossing Structures for Amphibians and Reptiles ............................14
4.1.2 Crossing Structure Design ..............................................................................24
4.1.3 Crossing Structure Location and Spacing .......................................................28
4.1.4 Retrofitting Existing Drainage Culverts ...........................................................30
4.1.5 Taxa-specific Recommendations.....................................................................30
4.2 Fencing for Reptile and Amphibian Crossings ..............................................................36
4.2.1 Fence Design ..................................................................................................36
4.2.2 Fence Placement ............................................................................................42
4.2.3 Fence Maintenance ........................................................................................45
5 SUPPLEMENTARY MEASURES .................................................................................45
5.1 Influencing Driver Behaviour .......................................................................................45
5.2 Influencing Wildlife Movement ...................................................................................47
6 TEMPORARY MITIGATION DURING ROAD CONSTRUCTION ......................50
6.1 Timing of Construction Activities ................................................................................50
6.2 Mitigation Measures for Construction Activities .........................................................50
7 MONITORING ................................................................................................................51
7.1 Study Design ...............................................................................................................51
7.2 Monitoring Techniques ................................................................................................53
7.2.1 Road Surveys ..................................................................................................53
7.2.2 Crossing Structure and Fencing Effectiveness ................................................55
7.2.3 Population Estimates ......................................................................................59
7.3 Adaptive Management ...............................................................................................59
8 REFERENCES ..................................................................................................................60
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9 APPENDICES
Appendix A: SAR AMPHIBIAN AND REPTILE HABITAT USE AND MOVEMENTS ............76
Appendix B: DEFINITIONS ................................................................................................83
Appendix C: CROSSING STRUCTURE SUMMARY FROM LITERATURE ............................84
Appendix D: LINKS AND OTHER RESOURCES .................................................................99
Appendix E: SAMPLE TUNNEL COSTS TABLE (2014) .....................................................100
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This document presents current information
1 INTRODUCTION
as of the date of publication and is meant
to be updated through time as improved
1.1 Purpose
information becomes available. If you are
interested in providing pertinent information
The purpose of the Ontario Ministry of
for consideration in updates of this document,
Natural Resources and Forestry (OMNRF)
please email [email protected].
Best Management Practices for Mitigating
the Effects of Roads on Amphibian and
Reptile Species at Risk in Ontario (hereafter
1.2 Endangered Species Act, 2007
referred to as the best management practice
(ESA)
(BMP) document) is to provide information
on designing, implementing and monitoring
The ESA provides the legislative framework
mitigation measures to restore connectivity and
for the protection of species at risk in Ontario.
reduce road mortality for species at risk (SAR)
Section 9 of the ESA includes prohibitions
amphibians and reptiles. This information will
against activities such as killing, harming,
assist in providing information on mitigation
harassing, capturing or taking a living member
planning for amphibians and reptiles at risk in
of a species that is listed as extirpated,
Ontario in order to meet the requirements of
endangered or threatened on the Species at
the Endangered Species Act, 2007 (ESA) or its
Risk in Ontario (SARO) List. Section 10 of the
associated regulations. The intended audience
ESA includes prohibitions against damage or
includes planning authorities (local or provincial
destruction of the habitat of an endangered or
government), individuals applying ESA
threatened species.
requirements on the landscape, consultants
working on their behalf and conservation
The ESA contains provisions that enable
organizations involved in the planning and
the Minister to issue permits and enter
design of impact mitigation for all new roads
into agreements to authorize activities that
and road rehabilitation (improvement) projects.
would otherwise be prohibited and Ontario
Regulation 242/08 sets out conditional
The focus of this BMP document is on crossing
exemptions from prohibitions under the Act for
structures and fencing. While there is no
certain activities. For additional information,
singular solution for mitigating road effects
visit the government website or read the full
on amphibians and reptiles, this document
text of the legislation on e-Laws using the links
offers information for developing site-specific
provided below.
mitigation based on best practices and findings
from current peer-reviewed and grey literature
How species at risk are protected:
(e.g., websites and conference proceedings),
https://www.ontario.ca/page/how-species-risk-
government documents, academic theses
are-protected
and personal communication surveys with
experts in road ecology and other areas of
Endangered Species Act, 2007 on e-Laws:
relevance (e.g., engineering, species biology).
http://www.ontario.ca/laws/statute/07e06
When knowledge gaps were identified, the
recommendations are based on the best
Ontario Regulation 242/08 on e-Laws:
available information and expert opinion, as
http://www.ontario.ca/laws/regulation/080242
well as logical interpretation from species-
specific needs and life-history traits.
45 5
1.3 Document Outline Section 7 (Monitoring) highlights where there
are knowledge gaps about effectiveness
This document is organized into the following of mitigation measures for reducing road
sections: impacts on amphibians and reptiles. Study
Section 1 (Introduction) provides background design and monitoring techniques for
information on the threats of roads to measuring crossing structure and fencing
amphibian and reptile species and the effectiveness, in an adaptive approach, are
overall objectives of the document. discussed.
Section 2 (The Impacts of Roads) details
References
background information on the impacts of
roads on amphibians and reptiles and the
need for road mitigation measures. Appendix A (SAR Amphibian and Reptile
Habitat Use and Movement) provides a
Section 3 (Mitigation Planning) provides general summary of seasonal habitat use,
information about considerations for general movement distances within and
developing a mitigation plan in a landscape between habitat and when this occurs for
context within project planning processes. species at risk amphibians and reptiles in
Ontario.
Section 4 (Road Mitigation BMPs) addresses
design variations and applications of Appendix B (Definitions) provides a glossary
three crossing systems for amphibians of terms used throughout the document.
and reptiles, in addition to detailed
considerations for siting, designing, Appendix C (Crossing Structure Summary
enhancing and maintaining crossing from Literature) summarizes the findings
structure and fencing systems. from the literature-based review that
informed the recommendations throughout
Section 5 (Supplementary Measures) the document.
provides recommendations about using
mitigation measures other than crossing Appendix D (Links and Other Resources)
structures and fencing systems to reduce contains a list of useful references, which
road impacts on amphibians and reptiles. may be cross-referenced when developing
These measures may be used when a mitigation plan for SAR amphibians and
crossing structures are not required, or as a reptiles.
complement to an effective mitigation plan.
Appendix E (Sample Tunnel Cost Table
Section 6 (Temporary Mitigation During (2014) contains the cost per metre for
Road Construction) provides considerations round and box tunnels, as well as special
for reducing impacts from construction installation considerations.
activities, including timing construction
activities to avoid construction-related
impacts, and considerations regarding the
use of temporary mitigation measures to
minimize impacts during construction.
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thermoregulation (Andrews et al. 2008). Snakes
2 IMPACTS OF ROADS
may also avoid crossing roads altogether,
which may disrupt normal behaviours, prevent
Globally, there are significantly more amphibian
access to key habitats, and lead to reduced
and reptile species at risk than either mammals
genetic diversity (Shine et al. 2004, Rouse et al.
or birds (IUCN 2010). Amphibians and reptiles
2011, Robson and Blouin-Demers 2013). Road
were the most negatively affected species
mortality of more than three adult females per
groups in a meta-analysis using data from
year can lead to declines for some long-lived
75 studies that quantitatively measured the
snake populations such as the Gray Ratsnake
relationship between roads or traffic and
(Row et al. 2007).
population size (Rytwinski and Fahrig 2012).
The threats of roads to amphibian and reptile
Modelling studies suggest that populations
populations in Ontario are well-documented,
of many turtle species are declining because
and primarily include direct mortality of animals
of the high rates of annual traffic mortality
as well as habitat loss, degradation and
in some areas (Gibbs and Shriver 2002).
fragmentation (e.g., Fahrig et al. 1995, Ashley
Turtles are particularly vulnerable to traffic
and Robinson 1996, Findlay and Houlahan
mortality because their life history strategy
1997, Vos and Chardon 1998, Haxton 2000,
is characterized by long life spans, delayed
MacKinnon et al. 2005, Crowley 2006, Seburn
maturity (sometimes taking more than 20
2007, Eigenbrod et al. 2008a, Eberhardt et al.
years), and very high adult survivorship. As a
2013).
result even small, but ongoing, increases in
adult mortality can lead to population declines
In southern Ontario the network of major
(Congdon et al. 1993) and recovery is slow
roads increased from 7000 km to over 35 000
(Brooks et al. 1991). Females are threatened
km from 1935 to 1995 (Fenech et al. 2001).
by traffic mortality because of overland
Consequently, there is no point in southern
movements to nesting areas (Steen et al. 2012)
Ontario that is further than 1.5 km from a road
and populations of some species have been
(Gunson et al. 2012), and remaining natural
found to be male-biased in wetlands in areas
habitat is isolated into patches. In addition,
with high road density (Marchand and Litvaitis
human population growth is projected to
2004, Steen and Gibbs 2004).
increase by at least 30% over the next 20 years
in the Greater Golden Horseshoe, increasing
Amphibians are subject to road mortality when
traffic volume and pressure for road expansions
migrating to wetland breeding sites and this
and rehabilitation. With properly planned and
can range from 19% (Gibbs and Shriver, 2005)
implemented road ecology solutions, these
to as high as 98% (Hels and Buchwald, 2001)
impacts can be lessened across Ontario.
depending on traffic volumes (Bouchard et al.
2009). Road mortality of just 10% of the adult
Monitoring has documented significant levels
population can lead to population extinctions
of road mortality (van Gelder 1973, Rosen and
(Gibbs and Shriver, 2005), resulting in lower
Lowe 1994, Ashley and Robinson 1996, Aresco
species richness and abundance of individuals
2005) and road barrier effects (Andrews and
near roads (e.g., Carr and Fahrig, 2001;
Gibbons 2005) for amphibians and reptiles.
Eigenbrod et al., 2008). In addition, Karraker
Snakes are particularly vulnerable to road
and Gibbs (2011) found road mortality reduced
mortality because some species immobilize in
the life expectancy of Spotted Salamanders
response to a passing vehicle (Andrews and
(Ambystoma maculatum) next to roads, and
Gibbons 2005), or may bask on the roadway for
67 7
because younger salamanders lay smaller egg 3 MITIGATION PLANNING
masses this also reduced reproductive output.
In addition to road mortality, roads also inhibit 3.1. Project-Level Impact Avoidance
movements of amphibians (deMaynadier and and Mitigation
Hunter 2000) which can potentially restrict
gene flow (Marsh et al. 2008). Project planning and design for roads is a
stepwise process that begins with defining
the study area for new road construction
or other major road rehabilitation projects.
Meese et al. (2009) identifies the potential
impacts of different types of road projects on
wildlife species in general (Table 1). The list of
project types is not meant to be exhaustive
but rather to include major road improvements
and rehabilitations within the scope of this
document. There are other impacts to SAR
during road operations and maintenance
activities such as shoulder grading and paving
that are not covered in this document. Projects
should be designed to avoid impacts whenever
possible, and this is best achieved by locating
roads to avoid species at risk habitat altogether.
When impacts are unavoidable, appropriate
authorizations need to be obtained and the
necessary mitigation measures incorporated
into the project design.
3.2 Project Planning Considerations
and Sources of Information
The information in this document outlines
considerations for devising and integrating a
mitigation plan into the road planning process
in situations when avoidance cannot be
achieved. New roads or road improvements
present opportunities to lessen the impacts on
SAR by integrating mitigation measures. These
mitigation measures include specialized tunnels
for wildlife passage as well as modifying or
retrofitting existing drainage crossings for both
water and wildlife use.
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Table 1: A summary of project types during road improvement and rehabilitation activities,
and potential impacts on amphibians and reptiles (adapted from Meese et al. 2009).
Road Activity Project Type Impacts on SAR
Road improvement New road alignment or Bisection of existing habitat and
extension movement routes; genetic isolation
of populations; road mortality;
habitat loss
Road improvement Road widening Increased traffic volumes and road
width increase risk of road mortality
(Gibbs and Shriver 2002); habitat
loss
Road improvements Creation of median and Increased barriers and road corridor
installation of shoulder width increase risk of road mortality
barriers
Road rehabilitation Culvert or bridge May provide opportunities or
improvements barriers to movement, depending on
resulting permeability of structure
(Kintsch and Cramer 2011); risk
of destroying turtle nests if work
is carried out during the nesting
period
Road rehabilitation Improved road pavements Increased risk of road mortality and
disturbance of animals
Implementation of the mitigation plan begins to the mitigation specifications needs to be
during the construction phase, and particular practiced for each project. Routine quality
attention to design details is important for checks to ensure that implementation of
amphibians and reptiles. It is important for all mitigation measures is not misinterpreted
individuals involved in construction projects, during construction, and routine maintenance
including road crews, to be aware of the of mitigation measures following construction
mitigation measures to be implemented for is required.
the project. Oversight by individuals with
the greatest understanding of the mitigation Compiling field and geographic information
measures is imperative to ensure that effective system (GIS) data can support the
road mitigation solutions are implemented. For development of an effective mitigation
example, a fence with a gap or a fence buried plan. Standard data compilations include
improperly can render the mitigation measures species occurrence data obtained from the
ineffective. Quality assurance and adherence MNRF or other sources; these data are best
89 9
supplemented with additional road survey Defined road impacts and objectives for
data and species presence data collected in mitigation will provide the content and
the project study area using standard survey scope of the mitigation plan.
techniques (see section 7.2.1). In the case
of larger road projects, the duration of the Step 2: Design and determine the location
environmental assessment (EA) process can of mitigation measures such as crossing
last up to ten years, especially if there are time structures and fencing by combining
lapses between the preliminary assessment, ecological data (e.g., species, habitat and
detail design and construction. This provides landscape information) with engineering
opportunities for formal data collection within data (e.g., geomorphological, hydrological
the project study area that can inform both and topographical). This step requires
mitigation planning and assessments of the collaboration between the ecological
effectiveness of mitigation. and engineering design team to ensure
fluid integration of information into the
Georeferenced data that may be available mitigation plan. For a road rehabilitation
to support project planning and design may project, there may be opportunities to
include the following: retrofit existing infrastructure. Through
l Existing and future land use and ownership careful evaluation, existing bridges and
maps, drainage culverts may be used or adapted
l Habitat mapping (e.g., Southern Ontario for amphibians and reptiles (see section
Land Resource Information System, or 4.1.4).
Ecological Land Classifications),
l Species at risk occurrence information Step 3: Consider a multi-species perspective
(Natural Heritage Information Centre), to ensure that a strategy for an individual
l Terrain features, species does not create unintended impacts
l Natural Heritage Systems, and for other wildlife species. Supplementary
l Existing and future road network and other measures such as warning signs at fence
infrastructure (i.e., existing barriers or ends may complement a multi-species
passageways, including culverts, median strategy (see section 5).
and shoulder barriers, and adjacent
railroads, local or private roads). Step 4: Identify temporary mitigation
measures. This could include carrying out
road construction when animals are not
3.3 Recommended Process active, timing construction at particular
road sections when animal activity is
The recommended steps for developing minimal (see section 6.1) and installing
a comprehensive mitigation plan for SAR temporary mitigation measures (see section
amphibians and reptiles are outlined in Figure 6.2).
1 and described below.
Step 5: Develop a monitoring plan for
Step 1: Identify and prioritize sections of roads evaluating the effectiveness of the
that will impede connectivity and/or pose mitigation. Refer to section 7 for information
mortality risk to amphibians and reptiles on developing a complete monitoring plan
using field data collections and additional that addresses the uncertainty with respect
landscape information (see section 3.4). to mitigation design.
1110