Survival, Recruitment, and Population Growth Rate of an Important Mesopredator: The Northern Raccoon

Abstract

Populations of mesopredators (mid-sized mammalian carnivores) are expanding in size and range amid declining apex predator populations and ever-growing human presence, leading to significant ecological impacts. Despite their obvious importance, population dynamics have scarcely been studied for most mesopredator species. Information on basic population parameters and processes under a range of conditions is necessary for managing these species. Here we investigate survival, recruitment, and population growth rate of a widely distributed and abundant mesopredator, the northern raccoon (Procyon lotor), using Pradel’s temporal symmetry models and >6 years of monthly capture-mark-recapture data collected in a protected area. Monthly apparent survival probability was higher for females (0.949, 95% CI = 0.936–0.960) than for males (0.908, 95% CI = 0.893–0.920), while monthly recruitment rate was higher for males (0.091, 95% CI = 0.078–0.106) than for females (0.054, 95% CI = 0.042–0.067). Finally, monthly realized population growth rate was 1.000 (95% CI = 0.996–1.004), indicating that our study population has reached a stable equilibrium in this relatively undisturbed habitat. There was little evidence for substantial temporal variation in population growth rate or its components. Our study is one of the first to quantify survival, recruitment, and realized population growth rate of raccoons using long-term data and rigorous statistical models.

Which mechanisms drive seasonal rabies outbreaks in raccoons? A test using dynamic social network models

“…Here, we suggest that latitudinal differences in the timing of rabies outbreaks could be more closely related to weather patterns than to different patterns of seasonal birth pulses (Duke-Sylvester, Bolzoni & Real 2011). Even if our simulation models had shown that seasonal mating peaks led to seasonal rabies outbreaks, any variation in the mating season may not be particularly important to rabies outbreak patterns because the timing of the mating and birth peaks does not appear to differ substantially across a latitudinal gradient (Gehrt & Fritzell 1998a,b;Chamberlain 1999;Hauver et al 2010;Rosatte et al 2010;Duke-Sylvester, Bolzoni & Real 2011;Troyer et al 2014). However, there is evidence that the duration of these mating and birthing seasons may be longer in southern populations (Troyer et al 2014).…”

“…; Duke‐Sylvester, Bolzoni & Real ; Troyer et al . ). However, there is evidence that the duration of these mating and birthing seasons may be longer in southern populations (Troyer et al .…”

Spatiotemporal dynamics of mesocarnivore populations

“…Raccoons are the effective predators of avian nests and small mammals, and also scavenge for food from human residence in the rural areas. It is reasonable to expect raccoon populations increase in the landscape disturbed by human residential establishment and agriculture owing to enhanced food availability (Beasley et al 2011, Troyer et al 2014b. With increasing raccoon population size and limited number of mature trees for maternal denning, raccoon populations may become density dependently regulated and become stabilized at the carrying capacity (Beasley et al 2012).…”

“…Despite the critical roles, few studies have investigated the density dependence of mesocarnivores compared to large herbivores and small mammals (Troyer et al 2014a). Little was known regarding the population ecology of raccoons (Troyer et al 2014b). In this study, we used 14 23-year capture per unit effort (CPUE) time series of raccoons collected from 14 wildlife management areas (WMAs) to investigate the spatiotemporal dynamics of raccoon populations in Mississippi, USA.…”

Onderzoek naar het voorkomen van de wasbeer in Nederland

“…Pogingen om de soort uit te roeien, mislukten. Momenteel zijn er gevestigde populaties in de meeste deelstaten, inclusief de aan Nederland grenzende deelstaten Nordrhein-Westfalen en Niedersachsen.Gedetailleerde wetenschappelijke studies naar de populatiedynamiek van Wasberen, groeisnelheden en de factoren en processen die hierop van invloed zijn, zijn tot op heden nauwelijks voorhanden(Troyer et al 2014). Globaal kan op basis van de registraties van afschot en valwild in Duitsland wel een indruk worden verkregen van de snelheid waarmee Wasbeerpopulaties kunnen toenemen (zie bijlage 5).…”