An independent committee of experts considers which plants and animals should be listed as at risk. The Committee on the Status of Species at Risk in Ontario (COSSARO) consists of up to 12 members with expertise in scientific disciplines or Aboriginal Traditional Knowledge.

The Endangered Species Act gives the committee legal recognition and specific responsibilities:

  • Maintaining criteria for assessing and classifying species
  • Keeping a list of species that should be assessed and classified (or reclassified) in the future
  • Assessing, reviewing and classifying species
  • Submitting reports regarding the classification of species and providing advice to the Minister of the Environment, Conservation and Parks

COSSARO Membership

AGENCY MEMBERS BIOGRAPHIES (Click + to view members biographies.)


Tom Hilditch is President and CEO of Savanta Inc., responsible for all aspects of Savanta including the technical quality of all ecological work completed. He is a former Vice-President, Environmental Management Practice Area, Central and Eastern Canada at Stantec Consulting and a former Senior Ecologist at Gartner Lee Limited. Mr. Hilditch was a member and Chair of the Species at Risk Program Advisory Committee from 2008 to 2014.


Dan Kraus is the Manager of Conservation Science and Planning for the Nature Conservancy of Canada (NCC) – Ontario Region. He is co-author of the Lake Ontario Biodiversity Conservation Strategy, the Great Lakes Islands Conservation and Biodiversity Atlas and Beyond Island of Green: A Primer for Using Conservation Science to Select and Design Community-Based Nature Reserves. Prior to joining NCC, Mr. Kraus was a senior ecologist for an environmental consultant. He is a member of the Society for Conservation Biology and the Ecological Society of America. Mr. Kraus has an undergraduate degree from the University of Waterloo in Environmental Studies and a M.Sc. from the University of Guelph.


Steven Paiero is a former Collection Technician with Natural Resources Canada. Mr. Paiero is a former Field Technician/Researcher and former Database Manager and Acting Curator of the Insect Collection with the University of Guelph. He is also a former Entomology Consultant with the Town of Markham. Mr. Paiero holds an Honours Bachelor of Sciences in Zoology, a Master of Sciences in Environmental Biology, and is currently completing a Doctor of Philosophy in Entomology from the University of Guelph.


Ashley Thomson is Assistant Professor at Lakehead University and former Ecologist at Resolute Forest Products and Postdoctoral Research Fellow at University of Michigan. Her community involvement includes serving as a Council member for Lakehead University Sustainability Stewardship Council.


Darren Sleep is Senior Director, Conservation Strategies at Sustainable Forestry Initiative (SFI). His former employment includes roles as Project Leader, Forest Ecology at The National Council for Air and Stream Improvement (NCASI). Community involvement includes serving as Chair of the Survival and Recovery Working Group for the Species at Risk Advisory Committee (SARAC).

How to apply to join COSSARO

If you are interested in becoming a member of the committee, please see the agency details and how to apply sections of the Public Appointments Secretariat webpage.