Population Modeling & Dispersal of Mottled Duskywing
Dr. Ryan Norris, Associate Professor at the University of Guelph, is working with master’s candidate, Angela Demarse and PhD candidate, Emily Trendos, on a comprehensive mark re-sighting study on Mottled Duskywing. This collaborative project with recovery team members Jessica Linton and Alderville Black Oak Savanna, will result in robust population estimates and daily survival rates for the two largest known populations of Mottled Duskywing in Ontario. The objective of the study is to collect data on population recruitment, adult lifespan, response to land management activities, and dispersal, which can be used in population modelling for the species.
Genetics and Landscaping Ecology of Mottled Duskywing
Dr. Nusha Keyghobadi, Associate Professor in the Department of Biology at Western University, is working with master’s candidate Shayla Kroeze, to develop the genetic markers for Mottled Duskywing and assess its genetic diversity. This will provide critical information about their current status in Ontario (and adjacent US States) that are not evident from physical, behavioural, or demographic observations alone. Genetic techniques are now widely used in conservation biology to identify source populations for reintroductions, resolve taxonomic status, and assess extinction risk (Frankham et al. 2002). This approach has been employed for other endangered butterflies in Canada such as the Mormon Metalmark (Apodemia mormo) (Crawford et al. 2011) and habitat specialists such as the Bog Copper (Lycaena epixanthe) (Crawford and Keyghobadi 2018).
The study team, which includes recovery team member Dr. Gard Otis (University of Guelph), are collecting wing clip samples according to the identified field protocols which are non-lethal, and do not negatively affect individuals or their behavior.
Mottled Duskywing Captive Rearing Project
In partnership with Dr. Sheila Colla (York University), Adrienne Brewster and Yvonne Young (Cambridge Butterfly Conservatory) developed a captive rearing protocol for Wild Indigo Duskywing (Erynnis baptisiae) in 2018. Having a carefully developed protocol which outlines handling protocols, sanitation procedures, best animal care practices, and most effective techniques for increasing population size was considered critical to recovery of Mottled Duskywing. Although the two duskywing species develop on different larval host plants, they share a number of common traits.
Adrienne Brewster and Yvonne Young began working with the endangered Mottled Duskywing in captivity in June 2019. Twelve females were taken in accordance with required permitting from the wild and placed in mesh oviposition enclosures in the environmentally-controlled conservation lab at Cambridge Butterfly Conservatory. Activities in 2019 focused on documenting oviposition rates, egg and larvae survival, refining the captive rearing techniques specific to Mottled Duskywing and finalizing a protocol, and conducting a density dependence experiment in collaboration with Ryan Norris and Angela Demarse (University of Guelph). The 2019 captive rearing project was a success with total, over 1800 eggs laid in captivity and high larval survival rates. The team gained important insights into the natural history of the species, finalized the captive rearing protocol for Mottled Duskywing, and were able to positively augment the population where the original twelve females were collected.
The captive rearing program continued in 2020 for research purposes and source populations were augmented with captively bred individuals. A successful partnership NSERC Alliance grant with the Norris Lab, has ensured this rearing program will be fully funded until 2025.
Learn more about the Cambridge Butterfly Conservatory at: https://www.cambridgebutterfly.com/
Pinegrove Productions Recovery Team Documentary
Pinegrove Productions (https://www.pinegroveproductions.ca) was founded in 1994. Since then they have evolved into a full service production studio. Since 2004 much of their work has focused on environmental issues – biodiversity, species at risk, habitat rehabilitation and other forms of stewardship. In creating these resources, they have partnered with, and have been supported by many different Conservation Authority’s, NGOs, scientists, landowners and educators in the province.
Pinegrove Productions has partnered with the Ontario Butterfly Species at Risk Recovery Team to create a documentary focused on the collaborative work of the Team to reintroduce Mottled Duskywing to formally occupied sites, restore habitat to establish new populations, and conduct research on existing populations. This will include collecting footage over two and half years of field and lab research, the captive rearing program, restoration work, and monitoring activities, as well as interviews with several team members. The resulting documentary will provide an opportunity for other researchers, conservation practitioners and the general public to share in our exciting road to recovery of Mottled Duskywing.
Tallgrass Habitat Creation
Several Recovery Team members and partner organizations are involved in the restoration and creation of tallgrass habitat in Ontario. The term “tallgrass communities” describes particular assemblages of flora and fauna which characterize prairie, oak savanna, and oak woodland systems in southern Ontario. Native oak savanna, prairie and woodland habitats once covered more than 11,000,000 hectares of North America, but are among the most endangered habitat types in Canada. It is estimated that 800 to 2,000 km2 of these vegetation community types existed in the southern Ontario landscape before European settlement and subsequent land conversion (Rodger 1998). Now these habitats occupy less than 3% of their former range in Ontario and what remains is under constant threat due to fire suppression and inadequate management (Taylor et al. 2014). The loss of this habitat has directly contributed to the decline of Ontario’s butterfly fauna and has led to the extirpation of three of Canada’s butterfly species at risk: Karner Blue, Frosted Elfin, and Eastern Persius Duskywing and range reduction of Mottled Duskywing.
Pinery Provincial Park supports a globally rare oak savanna ecosystem and is the largest protected forested area (2,532 ha) in southwestern Ontario. The park was occupied by Mottled Duskywing until the early 1990’s and several factors likely contributed to the loss of this species including fire suppression and extensive deer browsing of larval food plants. Today, the park has dramatically improved the quality of the oak savanna habitat through prescribed burning, invasive species control, and deer management. Ontario Parks staff will collaborate with our team members to plan the first reintroduction of Mottled Duskywing in the province to Pinery Provincial Park.
The Alderville Black Oak Savanna and Tallgrass Prairie manages a 40-ha property located near the southern shore of Rice Lake, ON. Their mission is to preserve, restore and expand rare grassland habitats on their property, as well as educate the public and community members. The traditional management of this land by Alderville First Nations has created, protected, and enhanced high quality, early successional habitat. The bulk of their ecological restoration work centres around three main activities: prescribed burning, planting native species, and invasive species control. One of the most important restoration techniques is the reintroduction of fire. Prescribed burns are a key part of Alderville’s management plan and are carried out in a scientific manner each spring. Fire is a key element in their management plan because it helps reduce invasive species which have not evolved to withstand fire, while promoting native species which depend on fire to reproduce and thrive. Another method of restoring grasslands is to remove invasive species such as Spotted Knapweed, Smooth Brome, Sweet White Clover, Dog Strangling Vine, and European Buckthorn. To maintain the open habitats of savannas and prairies, they also have to combat some native species as well such as Balsam Poplar, Trembling Aspen, and Staghorn Sumac. Without control of these species, natural succession would take place and the rare savanna habitats would become woodlands.
Tallgrass Ontario was established in 1999 to coordinate work by groups wishing to undertake conservation programs that would implement the Recovery Plan for Grassland Communities of Southern Ontario. The Recovery plan lists hundreds of tallgrass and savanna species, many of which are identified as threatened, endangered or extirpated. Today, they work to connect groups and individuals engaged in recovery efforts, promote scientific research, omplement landowner contact and stewardship projects, raise public awareness about tallgrass communities, generate funds for recovery efforts, and undertake on-the-ground grassland reconstruction and maintenance projects.
Nature Conservancy of Canada is working alongside the Ontario Butterfly Species at Risk Recovery Team to restore and enhance tallgrass habitat in several natural areas across southern Ontario. NCC is working in several natural areas that have small numbers of Mottled Duskywing present on the landscape or historically supported populations of the butterfly. Stewardship work to enhance habitat includes prescribed burning to maintain open habitat areas, removal of invasive species such as Scots pine, Autumn olive and multiflora rose, and direct seeding of New Jersey tea and other native pollinator plants. The areas being targeted for this work have been identified by the Ontario Species at Risk Butterfly Recovery Team as potential introduction sites for mottled duskywing.
Reintroductions and Augmentations
Following two years of captive rearing trials to inform the development of a Captive Rearing Manual for Mottled Duskywing, genetic and population-focused monitoring of extant populations, and testing potential source populations for Wolbachia and other bacterial endosymbionts, the Recovery Team is planning the first reintroduction of Mottled Duskywing to a formally occupied location at Pinery Provincial Park in 2021. To prepare for this reintroduction Recovery Team members have prepared a reintroduction plan and formulated a monitoring program which will be led by Wildlife Preservation Canada.
Using Pinery and the results of the monitoring program as a model, the Recovery Team is also preparing for a reintroduction of Mottled Duskywing to the Norfolk Sand Plains in a formally occupied location and a nearby created habitat by the Nature Conservancy of Canada.
The Recovery Team will also consider site-specific population augmentations with captively reared Mottled Duskywing in consultation with researchers and land managers as we build our knowledge and collect data on how naturally occurring and reintroduced populations.
It is intended that the work the Recovery Team is doing now to expand the range of self-sustaining Mottled Duskywing populations in Ontario will directly inform future recovery efforts for other butterfly species at risk in the province and beyond.