Population structure and gene flow of Geoffroy's cat (Leopardus geoffroyi) in the Uruguayan Savanna ecoregion

Felids are among the species most threatened by habitat fragmentation resulting from land-use change. In the Uruguayan Savanna ecoregion, about 30% of natural habitats have been lost, large felids have been eradicated from most of the region, and the impact of anthropogenic threats over the smaller species that remain is unknown. To develop management strategies, it is important to enhance knowledge about species population structure and landscape connectivity, particularly when land-use change will continue and intensify in the next years. In this study, we evaluate the population structure and gene flow of Geoffroy's cat in the Uruguayan Savanna ecoregion. We generated a matrix of 11 microsatellite loci for 70 individuals. Based on Bayesian approaches we found that within the Uruguayan Savanna, Geoffroy's cat shows high levels of genetic variability and no population structure. However, we observed genetic differences between individuals from the Uruguayan Savanna and those from the contiguous ecoregion, the Argentinian Humid Pampa. Four first-generation migrants from Humid Pampa were identified in the Uruguayan Savanna, suggesting a stronger gene flow in the west-east direction. We detected a past bottleneck followed by a subsequent recovery in Geoffroy's cat populations in both ecoregions. These results lay the groundwork to understand the population dynamics and conservation status of Geoffroy's cat in the Uruguayan Savanna ecoregion, and provide baseline data to establish population monitoring.Fil: Bou, Nadia. Ministerio de Educacion y Cultura.; UruguayFil: Soutullo, Álvaro. Universidad de la Republica; UruguayFil: Hernández, Daniel. Laboratorio de Control Ambiental; UruguayFil: Mannise, Natalia. Ministerio de Educacion y Cultura.; UruguayFil: González, Susana. Ministerio de Educacion y Cultura.; UruguayFil: Bartesaghi, Lucía. Ministerio de Educacion y Cultura.; UruguayFil: Pereira, Javier Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Merino, Mariano Lisandro. Universidad Nacional del Noroeste de la Provincia de Buenos Aires. Centro de Bioinvestigaciones (Sede Junín); ArgentinaFil: Espinosa, Caroline. Universidade Federal do Rio Grande do Sul; BrasilFil: Trigo, Tatiane C.. Museu de Ciencias Naturais; ArgentinaFil: Cosse, Mariana. Ministerio de Educacion y Cultura.; Urugua

Margay (Leopardus wiedii) in the southernmost Atlantic Forest: Density and activity patterns under different levels of anthropogenic disturbance.

The margay (Leopardus wiedii) is a small Neotropical arboreal wild cat. This species is thought to be forest-dependent, although few studies so far have directly evaluated the relationships between spatiotemporal aspects of its ecology and landscape characteristics. The aim of this study was to estimate margay population density and activity patterns in six areas with different habitat types and levels of anthropogenic disturbance in the southernmost Atlantic Forest of Brazil. Our working hypothesis was that density and activity patterns differed between areas in response to differences in forest cover and anthropogenic disturbance. Margay records were obtained using camera trapping, during spring and summer from 2017 to 2019. In all areas, the sampling scheme consisted of 20 un-baited stations, set 1km apart, each containing two paired cameras. We assessed the potential effects of environmental variables, including anthropogenic factors, on margay density, rate of detection and space use by comparing nine spatial capture-recapture (SCR) models. Activity patterns of the margay, its potential prey, and competitors were described and compared using the date and time of the records. We obtained 66 records of margay. Two of the six sampled areas were excluded from subsequent analyses due to the small number of records. The density estimated by the top-ranked model varied from 9.6±6.4 individuals/100km2 in the area with the highest human disturbance to 37.4±15.1 individuals/100km2 in a less disturbed area. Margay densities responded positively to vegetation cover, supporting the hypothesis of forest dependence by the species. Both the margay and their potential prey (small rodents and marsupials) were found to be mostly nocturnal. Margay activity also overlapped with that of the ocelot, Leopardus pardalis, and with mammals associated with human presence (wild boar, cattle, domestic dogs and cats). This is the first multi-area study on patterns of density and activity of the margay in the Brazilian Atlantic Forest. We concluded that the margay is mostly nocturnal, and while its densities are positively influenced by forest cover and negatively influenced by human disturbance, the activity pattern of the species does not seem to change across landscapes with distinct levels of human modification. Margay populations seem to be able to persist under moderate levels of habitat modification, highlighting the importance of preserving even small native forest remnants in the highly fragmented Atlantic Forest

Comparative Assessment of Genetic and Morphological Variation at an Extensive Hybrid Zone between Two Wild Cats in Southern Brazil

<div><p>Increased attention towards the Neotropical cats <i>Leopardus guttulus</i> and <i>L. geoffroyi</i> was prompted after genetic studies identified the occurrence of extensive hybridization between them at their geographic contact zone in southern Brazil. This is a region where two biomes intersect, each of which is associated with one of the hybridizing species (Atlantic Forest with <i>L. guttulus</i> and Pampas with <i>L. geoffroyi</i>). In this study, we conducted in-depth analyses of multiple molecular markers aiming to characterize the magnitude and spatial structure of this hybrid zone. We also performed a morphological assessment of these species, aiming to test their phenotypic differentiation at the contact zone, as well as the correlation between morphological features and the admixture status of the individuals. We found strong evidence for extensive and complex hybridization, with at least 40% of the individuals sampled in Rio Grande do Sul state (southernmost Brazil) identified as hybrids resulting from post-F1 generations. Despite such a high level of hybridization, samples collected in this state still comprised two recognizable clusters (genetically and morphologically). Genetically pure individuals were sampled mainly in regions farther from the contact zone, while hybrids concentrated in a central region (exactly at the interface between the two biomes). The morphological data set also revealed a strong spatial structure, which was correlated with the molecular results but displayed an even more marked separation between the clusters. Hybrids often did not present intermediate body sizes and could not be clearly distinguished morphologically from the parental forms. This observation suggests that some selective pressure may be acting on the hybrids, limiting their dispersal away from the hybrid zone and perhaps favoring genomic combinations that maintain adaptive phenotypic features of one or the other parental species.</p></div

Individuals identified as hybrids between <i>L. guttulus</i> and <i>L. geoffroyi</i> in RS state, Brazil.

<p>NH and STR are the probabilities of association of each individual to its phenotypic population based on the NEWHYBRIDS and STRUCTURE analyses of microsatellites, respectively. The three columns labeled ‘mtDNA’, ‘X’ and ‘Y’ correspond to the species-specific haplotypes from sequence-based markers (mitochondrial DNA, X and Y chromosome introns, respectively) observed for each specimen.</p><p>*female individual, NA  =  not analyzed, <i>Lge</i>  =  haplotype inferred to originate from <i>L. geoffroyi, Lgut</i>  =  haplotype inferred to originate from <i>L. guttulus</i>.</p><p>Individuals identified as hybrids between <i>L. guttulus</i> and <i>L. geoffroyi</i> in RS state, Brazil.</p

Map showing the location of the study area within South America (left), and an enlarged view (right) depicting sample collection points.

<p>Red and blue circles represent collection locales for <i>Leopardus guttulus</i> and <i>L. geoffroyi</i>, respectively. The area depicted in darker shading in the enlarged map is Rio Grande do Sul (RS) state, where hybridization between these species has been documented. Samples collected inside RS where included in the analyses as the hybridizing populations, while those sampled outside RS were putatively considered to comprise parental/control populations, pending on genetic assessments (see text for details).</p

Levels of genetic differentiation between parental populations of both species and between samples collected from Rio Grande do Sul state (RS).

<p>Microsatellite data were evaluated with <i>F_ST</i> (left) and <i>R_ST</i> (right). Sequence-based markers, including mitochondrial DNA (mtDNA), X-linked and Y-linked introns, were evaluated with Ф<i>_ST</i>. All values were statistically significant (p<0.001).</p><p>Lge  =  <i>Leopardus geoffroyi</i>; Lgut  =  <i>L. guttulus</i>.</p><p>Levels of genetic differentiation between parental populations of both species and between samples collected from Rio Grande do Sul state (RS).</p

Factorial Correspondence Analysis (FCA) of autosomal microsatellite data.

<p>The graph shows the individual scores for parental and hybridizing populations of <i>Leopardus guttulus</i> and <i>L. geoffroyi</i> on the first two factor axes. Parental populations are delimited by circles (<i>L. guttulus</i> – dark red; <i>L. geoffroyi</i> – dark blue).</p

Results of the morphometric analyses.

<p>Principal Component Analysis (PCA) results are shown as graphs combining scores of the first (PCI) and second (PCII) principal components for: (A) all the assessed specimens, including information on whether each individual was identified genetically as pure <i>L. guttulus</i> (red circles), pure <i>L. geoffroyi</i> (blue circles) or a hybrid (green diamonds); (B) only male specimens identified genetically as pure <i>L. guttulus</i> (red circles) and pure <i>L. geoffroyi</i> (blue circles); and (C) same sample set as in (B), with the addition of genetically identified hybrids. Red and blue polygons (or ellipses) demarcate the morphological space encompassed by pure <i>L. guttulus</i> and <i>L. geoffroyi</i> individuals, respectively.</p

Results of the Bayesian analysis performed with STRUCTURE on the simulated genotypes.

<p>The values include the average proportion of assignment of each simulated hybrid category considering two clusters, and the percentage of correct assignment of each category under two thresholds (0.9 and 0.8).</p><p>Lge  =  <i>Leopardus geoffroyi</i>, Lgut  =  <i>L. guttulus</i>, Bc  =  backcross (the parental direction of the backcross is indicated on the right).</p><p>Results of the Bayesian analysis performed with STRUCTURE on the simulated genotypes.</p