Mesocarnivores

Interspecific interactions among mesocarnivores can influence community dynamics and resource partitioning. Insights into these interactions can enhance understanding of local ecological processes that have impacts on pathogen transmission, such as the rabies lyssavirus. Host species ecology can provide an important baseline for disease management strategies especially in biologically diverse ecosystems and heterogeneous landscapes. We used a mesocarnivore guild native to the southwestern United States, a regional rabies
hotspot, that are prone to rabies outbreaks as our study system. Gray foxes (Urocyon cinereoargenteus), striped skunks (Mephitis mephitis), bobcats (Lynx rufus), and coyotes (Canis latrans) share large portions of their geographic ranges and can compete for resources, occupy similar niches, and influence population dynamics of each other. We deployed 80 cameras across two mountain ranges in Arizona, stratified by vegetation type. We used two-stage modeling to gain insight into species occurrence and co-occurrence patterns. There was strong evidence for the effects of elevation, season, and temperature impacting
detection probability of all four species, with understory height and canopy cover also influencing gray foxes and skunks. For all four mesocarnivores, a second stage multi-species co-occurrence model better explained patterns of detection than the single-species occurrence model. These four species are influencing the space use of each other and are likely competing for resources seasonally. We did not observe spatial partitioning between these competitors, likely due to an abundance of cover and food resources in the biologically diverse system we studied. From our results we can draw inferences on community dynamics to inform rabies management in a regional hotspot. Understanding environmental factors in disease hotspots can provide useful information to develop more reliable early-warning systems for viral outbreaks. We recommend that disease management focus on delivering oral vaccine baits onto the landscape when natural food resources are less abundant, specifically during the two drier seasons in Arizona (pre-monsoon spring and autumn) to maximize
intake by all mesocarnivores.

La variabilidad genética es un factor importante para la supervivencia de los individuos ya que permite a los individuos adaptarse a los cambios ambientales. A pesar de que al Nasua narica se le considera el único carnívoro verdaderamente sociable que habita en los bosques neotropicales, se sospecha que las poblaciones que habitan en Norteamérica se han aislado genéticamente de forma gradual, debido principalmente a la fragmentación y pérdida de hábitat.
Se analizaron la variabilidad y estructura genética del N. narica en cinco poblaciones de México (Parque Museo de La Venta, Parque Nacional El Tepozteco, Puerto Morelos, Punta Raza y Reserva de la Biosfera de Chamela-Cuixmala) mediante el uso de marcadores moleculares, 12 microsatélites específicos y un fragmento del gen de citocromo b. Los resultados mostraron niveles de moderados a altos en los indicadores de variabilidad genética para ambos marcadores genéticos. La heterocigosidad esperada (HE) fue de 0.664, mientras que la heterocigosidad observada (HO) fue de 0.774. La mayoría de los microsatélites se encontraron en equilibrio de Hardy-Weinberg. Todos los loci fueron polimórficos en las cinco poblaciones y el promedio de alelos por locus fue de 5.033 ± 1.794 (DE). La diversidad haplotípica (h) para las poblaciones en conjunto fue 0.968 ± 0.008 (DE) y la diversidad nucleotídica (π) de 0.007 ± 0.001 (DE).
Se registraron 22 haplotipos distintos, la mayoría fueron específicos de una de las áreas muestreadas, sólo tres se compartieron entre las distintas poblaciones. Se encontraron diferencias significativas entre las poblaciones de la Costa del Pacífico (Punta Raza y Reserva de la Biosfera Chamela-Cuixmala), las del centro (Parque Nacional El Tepozteco) y sureste del país (Parque Museo La Venta y Puerto Morelos), corroborando que el aislamiento genético tiene un efecto significativo en ésta especie resultando en una estructura genética compuesta por cinco diferentes subpoblaciones.

Understanding how species respond to habitat structure in landscapes transformed by human activities is crucial to design management strategies that promote the conservation of wildlife in human-created lands. The aim of this study was to test the ecological hypothesis that fine-grain habitat structure may be an important determinant of habitat use of medium-size predators across transformed landscapes when comparing with coarse habitat classification. We assess habitat use of species by using occupancy modeling framework accounting for imperfect detection, and obtained three LiDAR-derived vegetation metrics at different scale to describe the fine-grain habitat structure in a landscape comprised by native forest and exotic tree plantations in central-south Chile. Four species were detected: Lycalopex culpaeus, L. griseus, L. fulvipes and Leopardus guigna, L. culpaeus and L. griseus largely occurred throughout the study area (w = 0.54 ± 0.08 and 0.18 ± 0.04). Coefficients of the better-ranked models based on AIC indicated a positive relation between understory cover at 250 m scale and the habitat use of L. fulvipes, L. guigna and L. griseus, while a negative relation with the habitat use of L. culpaeus. On the other hand, habitat use of L. fulvipes and L. guigna increased as structural diversity of forest increased while the habitat use of L. culpaeus and L. griseus decreased. Low support was found for the habitat use of L. guigna and L. culpeus being affected by habitat type (plantation or native forest). Our results showed that habitat use of these mesocarnivores responded to fine-grain habitat structure attributes as derived from LiDAR, but only some of them responded weakly to habitat type. Both results indicate that understory structure, and not a coarse classification of habitat type, may be better determinants for explaining the habitat use of native carnivores in this landscape comprised by native habitat and forest plantations. Our results can be extended to sustainable management of forest plantations for carnivore conservation by enhancing the vegetation structure of native shrub species within these production-oriented lands.

Las aberraciones cromáticas ocurren en mamíferos con poca frecuencia. El leucismo es la pérdida parcial o total de la pigmentación, dicha condición deriva de mutaciones genéticas. En este trabajo se presenta el primer registro de individuos leucísticos del coatí de nariz blanca Nasua narica en México.

The spatiotemporal distribution of a predator within an environment tends to be synchronized with that of its prey, to maximize the efficiency of its hunting behavior. However, small predators may also be obliged to avoid potentially agonistic encounters with larger predators due to interspecific competition and intraguild predation. We used occupancy models and indices of temporal overlap to evaluate whether the occurrence of prey species, ocelots (Leopardus pardalis) and top predators (puma Puma concolor and jaguar Panthera onca) influenced the habitat use and activity patterns of the northern tiger cat (Leopardus tigrinus) and jaguarundi (Herpailurus yagouaroundi) in a region of the semi-arid Caatinga biome inBahia, northeastern Brazil. The occurrence of prey had a positive influence on the use of habitat by the small felids. The northern tiger cat was nocturnal-crepuscular and presented a high degree of temporal overlap with Spix’s cavy (Galea spixii) and the rock cavy (Kerodon rupestris). The jaguarundi was diurnal, by contrast and overlapped temporally with the agouti (Dasyprocta nigriclunis). The occurrence of the ocelot did not influence the habitat or daily activity pattern of the jaguarundi, but presented a high degree of temporal overlap with the northern tiger cat, which adopted a strategy of spatial segregation to avoid direct contact with this dominant competitor. The top predators did not influence the spatiotemporal distribution of the small felids, indicating that their niches are segregated by dietary parameters related to differences in body size. Our results indicate that the availability of prey has a more profound influence on the spatiotemporal ecology of the small felids than the occurrence of the top predators, although the presence of the northern tiger cat appeared to be correlated negatively with that of the ocelot. We believe that environmental factors, such as the conservation status, size and isolation of native habitats, may have a fundamental influence on the strategies adopted by the northern tiger cat to mediate its coexistence with the ocelot.

Carnivores have a key role in ecosystems and their populations are declining at an increasing rate. Habitat loss and degradation through agricultural practices are among the most serious menaces affecting carnivore survival. Agricultural landscapes are dominant in Western Europe and in several places worldwide are changing quickly into more intensive practices. Therefore, it is important to understand how small carnivore occurrence and abundance is affected by these changes in order to find ways to manage agricultural and grazing systems in a sustainable way, allowing both biodiversity and production to co-exist. We present three case studies in Natura 2000 areas, mainly covered by private agricultural land (livestock, cereal crops, oak, pine and eucalyptus plantations) in southern Portugal. In areas of dominant traditional agro–silvo–pastoral systems (montado) small and middle-sized carnivores tend to occur in a mosaic of montado and shrubs. We found that the occurrence of one of the forest species was positively related with the density of trees and shrubs, soil organic matter content, and Shannon's index of vegetation vertical diversity. The presence of livestock and extension of game-estate areas also seem to influence carnivore occurrence. In areas of extensive cereal crops, the presence of shrubs and age of forest plantations play an important positive role for the carnivore community. Mainly our results suggest that maintaining a sustainable mosaic embracing montado, shrubland and open land areas, may allow higher species richness and abundance by enhancing connectivity between crucial areas. The implementation of this kind of agricultural practices considering the landowners needs is the key issue to achieve the main carnivore conservation goals in Southern Portugal.

Coatis (Procyonidae; 𝘕𝘢𝘴𝘶𝘢) are considered the only truly social mesocarnivore mammals in Neotropical forests. In Mexico, white-nosed coatis (𝘕𝘢𝘴𝘶𝘢 𝘯𝘢𝘳𝘪𝘤𝘢) are suspected to have undergone population reduction due to habitat loss and fragmentation and led to a lack of genetic adaptability and genetic isolation throughout its range. We examined patterns of genetic diversity and connectivity of five populations of Nasua narica distributed throughout Mexico (n = 60) by sequencing an ≈ 800 bp fragment of the mitochondrial cytochrome-
b gene and also by screening 12 microsatellite loci. We found moderate
to high levels of genetic variability for both genetic markers. We recorded
twenty-two different cytochrome-b haplotypes throughout the 5 sampled
areas and found that each of the sampled population of white-nosed coatis in Mexico harbors unique haplotypes and only three haplotypes were shared among two different populations that were closer geographically. All populations had high haplotype diversity (h) (0.968 ± 0.008 (SD)) but lower levels of nucleotide diversity (π) of 0.007 ± 0.001 (SD). All microsatellite loci were polymorphic in all of the populations and the mean number of alleles per locus was 5.033 ± 1.545 (SD) with expected (HE) and observed (HO) heterozygosity values of 0.774 and 0.664, respectively. However, low Wright F statistic values suggest the existence of a reduced heterozygosity (Fst = 0.203, Fis = 0.134 and Fit = 0.310). Significant differences between the five populations confirmed isolation by distance, which suggests genetic structure among five subpopulations.

— Riparian galleries are key structural elements of Mediterranean landscapes and their importance for carnivores has been widely demonstrated. However, humanization of the landscape has led to their degradation with consequences not fully understood. In this study we assessed the response of mesocarnivores to the fine-scale variation in the quality of a riparian gallery (Vale do Cobrão stream, central Portugal), evaluated on the basis of the QBR index ('Qualitat del Bosc de Ribera' in spanish) and an adaptation of the same considering mesocarnivore ecological requirements. These were represented through four parameters that could influence habitat quality for these species, namely refuge (total riparian cover, cover structure), disturbance and food availability. For the latter we considered the known main food resources for Mediterranean mesocarnivores: small mammals, lagomorphs, insects and fruits. Mesocarnivore use was evaluated through camera-trapping and sign surveys. For both indexes a concordance was observed between quality variation and its use by carnivores, and we also found a positive correlation between both indexes. The adapted QBR, being more laborious but also more realistic, could serve as guidance for conservation practice at the local scale, benefiting both land managers environmentally concerned, conservation practitioners and carnivore populations inhabiting humanized landscapes. However, for spatially wider approaches the original QBR proved to be a good indicator for the presence of mesocarnivores, being useful in the development of restauration or conservation strategies, as well as for research and monitoring activities of carnivore guilds.

Top predators can suppress mesopredators by killing them, competing for resources and
instilling fear, but it is unclear how suppression of mesopredators varies with the distribution
and abundance of top predators at large spatial scales and among different ecological
contexts. We suggest that suppression of mesopredators will be strongest where top
predators occur at high densities over large areas. These conditions are more likely to occur in
the core than on the margins of top predator ranges. We propose the Enemy Constraint
Hypothesis, which predicts weakened top-down effects on mesopredators towards the edge
of top predators’ ranges. Using bounty data from North America, Europe and Australia we
show that the effects of top predators on mesopredators increase from the margin towards
the core of their ranges, as predicted. Continuing global contraction of top predator ranges
could promote further release of mesopredator populations, altering ecosystem structure and
contributing to biodiversity loss.

Top predators can suppress mesopredators by killing them, competing for resources and instilling fear, but it is unclear how suppression of mesopredators varies with the distribution and abundance of top predators at large spatial scales and among different ecological contexts. We suggest that suppression of mesopredators will be strongest where top predators occur at high densities over large areas. These conditions are more likely to occur in the core than on the margins of top predator ranges. We propose the Enemy Constraint Hypothesis, which predicts weakened top-down effects on mesopredators towards the edge of top predators' ranges. Using bounty data from North America, Europe and Australia we show that the effects of top predators on mesopredators increase from the margin towards the core of their ranges, as predicted. Continuing global contraction of top predator ranges could promote further release of mesopredator populations, altering ecosystem structure and contributi...

We tested whether striped skunks (Mephitis mephitis) in Flagstaff, Arizona, USA, could be recognized based on variation in pelage patterns and whether camera position influenced that outcome. We presented 11 volunteers with 2 sets of 24 photographs taken between 1 January and 15 February 2015, one with animals photographed from the side, the other from above. Each set of 24 photographs included 9 pairs, with each pair representing 2 different images of the same animal. Volunteers scored twice as many correct matches and 4-fold fewer false matches when photographs were taken from above. Regardless of camera position, the total number of unique skunks in each set was underestimated (83% of total from above, 75% from side), likely because some skunks had very similar pelage patterns. Our results indicate that variation in nose stripe, back stripe, dorsal and ventral tail pattern, and shape of tail can be used to recognize individual striped skunks but similarity in those characteristics among some individuals may cause total number of unique individuals to be underestimated regardless of camera orientation.