Introduction

Pourquoi surveiller les rainettes faux-grillons de l'Ouest ?

The Western Chorus Frog (Pseudacris triseriata) is a small amphibian species found across Ontario that faces a number of threats, including habitat loss, climate change, and human activities (COSEWIC 2008; ECCC 2015; MRNF 2023). This webpage provides a summary of Best Management Practices (BMPs) to help landowners and land managers identify, protect, and restore WCF habitats while minimizing negative impacts (ECCC 2015; GUEPE 2022). If you are interested in learning more about these BMPs, please consider attending one of our BMP training webinars, information on upcoming events can be found here.

Identifying WCF Habitat

WCFs rely on both aquatic and terrestrial habitats. They breed in temporary wetlands or shallow portions of permanent wetlands, typically in waters 11-22 cm deep, though they have been found in water as deep as 40 cm (COSEWIC 2008; ECCC 2015; MRNF 2019). These wetlands provide essential breeding grounds with reduced predator presence.

In addition to breeding habitats, WCFs require terrestrial areas for foraging and hibernation. They prefer moist, open landscapes such as humid prairies, meadows, and moist woodlands (BSE 2023; UPA 2023)

Flooded fields, swamps, ponds, drainage ditches, and marshes (BSE 2022; ECCC 2015)
Vegetation includes herbaceous plants (cattails, sedges), occasional shrubs (alder, dogwood), and partially submerged trees (willows, red maple) (ECCC 2015; MELCCFP 2023)
Water accumulates from late fall to spring and dries up by mid-summer

Determining WCF Presence

PHYSICAL IDENTIFICATION

WCFs are small, brown-to-grey tree frogs, reaching up to 2.5 cm in length (COSEWIC 2008; ECCC 2014). They are distinguished by three dark dorsal stripes, a dark stripe between the eyes, and a broad mask extending from the nostrils past the tympanum (ECCC 2017; MELCCFP 2024). These markings help differentiate them from similar species.

AUDITORY IDENTIFICATION

The WCF call resembles the sound of a fingernail running along a comb (BSE 2023; GUEPE 2022). Differentiating their call from that of Spring Peepers (Pseudacris crucifer), which produce a high-pitched "peep," is crucial (ECCC 2015; Ouellet & Leheurteux 2007). To aid in identification, you can listen to an example call below or take our frog identification quiz.

Survey Protocols

BSE WCF LONG-TERM MONITORING PROTOCOL

Surveying for WCF populations is crucial for their conservation. A better understanding of their distribution and habitat connectivity allows us to identify and address potential threats more effectively.

You can find the protocol developed by BSE for our long-term monitoring of WCF populations in Ontario here.

ASSESSING WCF HABITAT

Assessing the health of WCF habitat and potential threats is key to identifying stewardship opportunities that support the species.

When identifying or evaluating potential WCF habitats, consider key features that support their survival. Ideal habitats include temporary wetlands, flooded fields, drainage ditches, ponds, and shallow portions of permanent wetlands that dry up in the summer.

Consider potential threats such as nearby busy roads, invasive plants like European Common Reed (Phragmites australis) and European Buckthorn (Rhamnus cathartica), and a high number of predators, including snakes, birds, larger frogs, and aquatic insects (MELCCFP 2023). Human activities, including land development and chemical run-off can also impact the function these fragile ecosystems.

Conducting Activities in WCF Habitat

TIMING WINDOWS

To minimize harm to WCFs, activities that may impact them should be conducted during periods of low activity for the species:

Light Maintenance: After August 1st (trimming, mowing) (Ouellet & Leheurteux 2007; BSE 2023)
Heavy Maintenance/Construction: Fall to early March (to avoid hibernation disturbance) (MRNF 2023)
Vegetation Control: Late Fall (BSE 2023; ALUS 2023)

REDUCING IMPACT TO HABITATS

Human activities should be carefully managed to prevent habitat degradation. Limiting activity areas and using existing routes can help reduce disturbances (MRNF 2016; UPA 2023). Preserving natural water and vegetation quality is essential, as is reducing pesticide, herbicide, and fertilizer use (ALUS 2023; Ouellet & Leheurteux 2007). Construction and other land-altering activities should be minimized near WCF habitats.

Enhancing & Restoring WCF Habitats

HABITAT IMPROVEMENT STRATEGIES

To improve WCF habitats, stewards can implement several strategies:

Increase wetland water storage and retention (MELCCFP 2023)
Reduce tree canopy cover to ensure 75% open habitat (BSE 2023)
Improve sun exposure to breeding ponds (MRNF 2019; UPA 2023)
Control invasive species following Ontario BMP guidelines (OIPC 2023)

Creating WCF Habitat

OPTIMAL HABITAT DESIGN

Ideal WCF habitats should be located in open landscapes with wetlands and sparse forests (MELCCFP 2023; MRNF 2016). Breeding ponds should measure at least 200m² in area, with a depth of 0.4-0.6m and a hydroperiod lasting 60-100 days (ECCC 2015). To ensure proper development, at least 60% direct sun exposure is necessary (ECCC 2015).

SITE SELECTION & MONITORING

Sites should be chosen based on factors such as minimal drainage alteration and low contamination risks (BSE 2023). Post-development monitoring should assess hydroperiod consistency, water quality, vegetation survival, and wildlife usage (MELCCFP 2023; MRNF 2023).

Managing WCF Habitat Connectivity

ROAD MORTALITY REDUCTION

Road crossings pose a significant risk to WCF populations. Installing culverts and amphibian tunnels with moisture-retaining substrates can help reduce mortality rates (COSEWIC 2008; MRNF 2016).

STEWARDSHIP PLANNING

Effective stewardship planning should focus on maintaining wetland buffers, preserving habitat connectivity, and restricting chemical use near WCF habitats (BSE, 2023). Forestry operations should be avoided near wetlands to prevent habitat fragmentation (ALUS 2023; Ouellet & Leheurteux, 2007).

REPORTING OBSERVATIONS

Observations can be submitted to the BSE website here. When possible data should include location, date, weather, habitat type, threats, and detection method (BSE 2023; MRNF 2023). Audio recordings and photos can be uploaded to confirm observations. Observations can also be shared on iNaturalist or with NHIC (BSE 2023).

References

Alternative Land-use Systems (ALUS). 2023. Sustainable Practices. Retrieved from: https://alus.ca/wp-content/uploads/2024/08/ALUS_3-Western-Chorus-Frog.pdf

Blazing Star Environmental (BSE). 2023. Best Management Practices for the Conservation of Western Chorus Frog and it’s Habitat in Ontario.

Blazing Star Environmental (BSE). 2022. Western Chorus Frog Long-Term Monitoring Program. Retrieved from: https://www.blazingstar.ca/_files/ugd/823189_0b354772b76e416e9ca5cde0106c165d.pdf

Committee on the Status of Endangered Wildlife in Canada (COSEWIC). 2008. COSEWIC assessment and update status report on the Western Chorus Frog Pseudacris triseriata Carolinian population and Great Lakes/St. Lawrence – Canadian Shield population in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 47 pp. (www.sararegistry.gc.ca/status/status_e.cfm).

Environment and Climate Change Canada (ECCC). 2015. Recovery Strategy for the Western Chorus Frog (Pseudacris triseriata), Great Lakes / St. Lawrence – Canadian Shield population, in Canada, Species at Risk Act Recovery Strategy Series, Environment Canada, Ottawa, vi + 50 pp. Retrieved from: https://www.canada.ca/en/environment-climate-change/services/species-risk-public-registry/recovery-strategies/western-chorus-frog-canadian-shield-population.html#_3_3

Groupe uni des éducateurs-naturalistes et professionnels en environnement (GUEPE). 2022. The Chorus Frog: A Flagship Species for Natural Environments. Retrieved from: https://prezi.com/p/7eb_ntdppg5h/the-chorus-frog/?present=1

Ministère des Ressources naturelles et des Forets (MRNF). 2019. Plan de rétablissement de la rainette faux-grillon de l’Ouest (Pseudacris triseriata) — 2019-2029. Prepared for the ministère des Forêts, de la Faune et des Parcs, Direction générale de la gestion de la faune et des habitats, 65 p. Retrieved from: https://mffp.gouv.qc.ca/documents/faune/PL_retablissement_Rainette_faux_grillon_2019-2029.pdf

Ministère des Ressources naturelles et des Forets (MRNF). 2023. 9 guide pratique pour la conservation de la rainette faux-grillon et son habitat. Retrieved from: https://www.rainette.ca/wp-content/uploads/Rainette_Depliant_9astuces_8.5x11_3volets_eng-lores.pdf

Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (MELCCFP). 2023. Breeding habitat development for the Western chorus frog. Guide, February 2023, Preliminary Version. Direction de la gestion de la faune de l'Estrie, de Montréal, de la Montérégie et de Laval, Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs, 18 pages and appendices. Retrieved from: https://mffp.gouv.qc.ca/documents/wildlife/GM_amenagement_habitat_rainette_faux-grilllon_en.pdf

Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (MELCCFP). 2024. Protocole standardisé pour l’inventaire de la rainette faux-grillon au Québec, gouvernement du Québec, Québec, 24 p. + annexes. Retrieved from: https://mffp.gouv.qc.ca/documents/faune/protocole_standardise_inventaire_rainette-faux-grillon.pdf

Ontario Invasive Plan Council (OIPC). 2024. Best Management Practices.

Available at: https://www.ontarioinvasiveplants.ca/resources/best-management-practices/

Ouellet & Leheurteux. 2007. Principles of Conservation and Development of Habitats of Amphibians: Literature Review and Recommendations Suggested for the Western Chorus Frog (Pseudacris triseriata). Amphibia-Nature for the MNRF. Retrieved from: https://www.amphibia-nature.org/download/pdf/PrincipesDeConservation-Amphibiens-2007.pdf

Union des Producteurs Agricoles (UPA). 2023. By learning more, we can protect better: Thirteen Species at Risk on Our Land. ALUS. Canadian Wildlife Federation. Supported by the Environment and Climate Change Canada (ECCC). Retrieved from: https://alus.ca/wp-content/uploads/2023/01/Outaouais_Species-at-risk_VF.pdf