Not All Mammalian Small Carnivores Are Equal: A Global Review of the Research Effort in Urban Areas

Human population increase and anthropogenic land-use changes are impacting biodiversity globally. Despite an increasing trend in urban wildlife studies, a systematic assessment of mammalian small carnivores in urban areas is still lacking. We evaluated urban studies in international peer-reviewed journals using a systematic review process. We assessed urban wildlife publications from 1970–2021 to quantify trends over time regarding the taxonomic family and geographical focus of publications across the globe. Urban small carnivore studies have increased progressively through the decades, with 87.2% of all studies conducted in the last 20 years. Geographically, we found that small carnivore studies were disproportionately conducted, with 77.0% of all studies taking place in either North America (46.5%) or Europe (30.5%). Furthermore, the United States of America (39.8%) and the United Kingdom (11.4%) contributed to 51.2% of all studies focused on small carnivores. We found seven carnivore families represented in urban studies, consisting of 76 species. Two canid species, Vulpes vulpes (21.9%) and Canis latrans (16.9%), accounted for 38.8% of all studies conducted on urban small carnivores. The majority of studies took place in mixed or urban areas (79.8%), with suburban and exurban zones explored to a lesser extent (16.6%). Animal behaviour was the most studied scientific topic (24.6%), with the least being species conservation (0.3%). Critical gaps persist in the research of small mammalian carnivores, particularly in rapidly urbanizing areas of Asia, Africa and South America. While the field of urban ecology will certainly continue to advance, we urge future research to adopt a multi-disciplinary stance that explores the landscape transitional zones, from the periphery of the urban core (sub-urban, peri-urban and exurban) into natural systems; or urban mosaic landscapes with natural and managed green spaces as refugia. The importance of urban fringe and margin areas for small carnivores remains largely unknown.