Bobcat (Lynx rufus) occurrence and felid co-occurrence: Abundance, competition, and trends in coat pattern variation

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Kelly J. Hood and Theodore Stankowich, California State University, Long Beach (CSULB), Anthony J. Giordano, Society for Preserving Endangered Carnivores and their International Ecological Study (S.P.E.C.I.E.S.), Rogelio Carrera Treviño, Universidad Autónoma de Nuevo León, Monterrey (UANL)

Background/Question/Methods
Where bobcats (Lynx rufus) co-occur with other intraguild felids aligns closely with the northern and southern geographic limits of their range. Their northern range is overlapped by the congener Canada lynx (Lynx canadensis), and their southern range is bordered by populations of mid-sized felids like ocelots (Leopardus pardalis), jaguarundi (Puma yagouaroundi), and margays (Leopardus wiedii). Coat patterns within the Lynx genus can vary widely, are highly heritable, and are suspected to be influenced by trends in ecological pressures. We are first investigating how felid co-occurrence affects bobcat abundance and occurrence using camera trap photographs from selected sites within the bobcat range. The first of our data comes from two non-consecutive 2-year sampling periods in Cumbres de Monterrey National Park, a densely vegetated habitat surrounded by desert, and from a continuous 1-year sampling period in Laguna Madre Protected Area along the north-eastern coast of Mexico. We use a spatially explicit capture-recapture framework to estimate co-occupancy, population density, and related parameters from camera data. We are also investigating whether coat pattern type is more uniform where bobcats co-occur more frequently with other felids to facilitate species recognition. We use our camera data to score bobcats for coat pattern type (plain, flecked, or rosette) along 6 body areas, and our competition co-occurrence information to compare pattern expressions to fluctuations in competition type.
Results/Conclusions
Our preliminary data provides important foundational information about bobcat co-occupancy and abundance in their southern range. In Cumbres de Monterrey, 39 camera locations captured 252 photographs of felids: 181 bobcat and 71 puma. In Laguna Madre, 28 camera locations captured 2,033 photographs of felids: 219 bobcat, 157 puma, 50 jaguarundi, and 1,607 ocelot. These preliminary findings indicate support for our hypothesis that as competition (occurrence of other intraguild felids) increases, bobcat density decreases. Data from subsequent years in these locations and from other locations throughout Mexico and the United States will be included in this study in the coming months. We have established a database of individuals using visually identifiable unique markers that will aide in both endeavors within this study: to investigate occurrence and abundance as well as coat pattern trends of the bobcat. It is too early to draw conclusions about trends in coat pattern variation, but we have found a greater ratio of rosette:flecked:plain patterns (showing more uniformity in occurrence of rosettes) in Laguna Madre than in Cumbres de Monterrey, where pattern types are more evenly expressed.