Historical surveys reveal a long-term decline in muskrat populations

The muskrat (Ondatra zibethicus) is an iconic species in Canada, valued for both its fur and its integral role in wetland ecosystems, and widely regarded for its perseverance. However, the resilience of this semi-aquatic mammal seems to be in question now as increasing evidence points to widespread population declines. Recent analyses of harvest data across North America suggest a reduction in their numbers, but this has not been widely corroborated by population surveys. In this study we replicated historic muskrat house count surveys at two large Great Lakes coastal wetlands and present confirmation that declines in muskrat harvest correspond to actual declines in muskrat abundance. At the Point Pelee National Park marsh and the Matchedash Bay-Gray Marsh wetland we found that mean muskrat house counts declined by 93% and 91% respectively between historic surveys 40-50 years ago and contemporary surveys over the past five years. The factors responsible for these dramatic declines remain unclear but there may be a relationship with changes in the habitat quality of these wetlands that have occurred over the same time frame. Not only is the loss of muskrats an issue for the resulting loss of the wetland ecosystem services they provide, but it may be an indication of broader marsh ecosystem degradation. As such, a scarcity of muskrats should be considered a red flag for the state of biodiversity in our wetlands. Continued surveys and ongoing research are needed to shed more light on the current status of muskrat populations and their marsh habitats across their native range. Keywords: Fur harvest; Muskrat; Ondatra; Population decline; Typha; Wetlands

Trialeurodes abutiloneus (Haldeman) (Hemiptera: Aleyrodidae), a species long present but never officially recorded in Canada

Trialeurodes abutiloneus (Haldeman) (Hemiptera: Aleyrodidae) is known to have been present in Canada since 1973. Despite this, the species has until now not been officially recorded; a surprising fact considering the close association of the species with economically important crops. The historic distribution expands from Mexico to southern New York and Michigan in the United States of America. In 2016, all life stages of T. abutiloneus were collected again on soybean (Glycine max (Linnaeus) Merrill; Fabaceae) plants grown in research greenhouses in southwestern Ontario, Canada. Specimens were morphologically and genetically identified to confirm their identity as T. abutiloneus. Thereafter, the barcode sequence for this species was also identified from the barcode of life data system, informing on the prior detection of this species from specimens collected at Point Pelee National Park, Ontario, Canada in 2012 during a barcode of life collection. Although this species is not considered a major pest on crops in Canada, it is related to other common pests within the same genus and can potentially transmit similar plant diseases. We provide the barcode COI sequence for the species, give an overview of the documented host range pertinent to Canada, and provide information concerning its natural enemies.