The role of red foxes in promoting functional connectivity of the Toronto ravine system through the urban matrix.

• Applicant: Tiziana A. Gelmi-Candusso, Ph.D.
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions ; Ecology and Biodiversity of Plants and Ecosystems
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 428765259

Urban red foxes (Vulpes vulpes) have been studied primarily for epidemiological reasons, however, they have an important role as seed dispersers. Seeds ingested by foxes include a vast number of plant species that may be carried for long distances, beyond the limits of other terrestrial mammals, and most importantly, across disturbed areas. The Toronto ravine system comprises nearly 20% of Toronto’s urban mosaic, it is composed of valleys and forests running through the urban matrix, and its biodiversity is disappearing at alarming rates, mainly due to non-native invasions. Red foxes might play a key role in the influx of seeds in ravines due to their ability to travel across the urban matrix, eating fruits opportunistically from gardens and orchards and hunting prey within the ravines, potentially linking highly disturbed green areas with ravine forest areas. Therefore, understanding seed dispersal by red foxes might be key in promoting landscape regeneration and containing alien expansion. However, no study yet has identified the plant species urban foxes disperse, nor identified their feeding areas and deposition areas. I aim to understand 1. Red fox movement patterns within patches of the urban mosaic and their differential use; 2. Identify fruit species dispersed around the city and their dispersal patterns; 3. Their potential seed dispersal distance. For this, I will use GPS devices to track their continuous movement and successively collect scats. Patches of the urban mosaic used by red foxes will be identified using iso-cluster categorization of the area in ArcGIS overlaid to movement data. Subsequently, in collaboration, I will develop models to further understand habitat use and land connectivity, i.e. a Bayesian state-space model to understand the differential use of habitats based on movement patterns, and a Network-based model of landscape dynamics to understand landscape connectivity based on the red fox dispersal capabilities. Seeds found in scats will be identified through barcoding since the DNA barcode reference library has sequence records for 96% of the 5108 known Canadian vascular plant species and their identification has been recently tested with high success rates using standard barcode markers (rbcL, matK, ITS2). Finally, potential seed dispersal distance for the most important dispersed species will be estimated following using movement data and gut passage time. Ultimately, I will answer whether red foxes are connecting urban green areas through seed exchange, which is the spatial extent of such functional connectivity and whether the array of seeds they disperse include invasive species that might pose a threat to the Toronto ravine system, or local species that will aid with its maintenance. The results of this analysis may then be of use for landscape management, promoting or limiting red fox movement to determined areas of the city based on their habitat use and their specific role in habitat regeneration.

• DFG Programme: Research Fellowships
• International Connection: Canada
• Host: Professorin Dr. Marie-Josée Fortin