DNA microsatellite characterization of the jaguar (Panthera onca) in Colombia

Comparative phylogeography among eight Neotropical wild cat species: no single evolutionary pattern

The felid species of South America are thought to have arrived on the continent during the Great American Biotic Interchange (GABI) in the Pleistocene. However, molecular and palaeontological data do not agree on how this event affected speciation in felids. Here, we determine both the number of colonization events and the period when felines first migrated from North America to South America. In addition, we evaluate whether similar evolutionary events could have affected the eight Neotropical cat species in their levels of genetic diversity, spatial genetic structure and demographic changes. We analysed four concatenated mitochondrial genes of the jaguar, ocelot, margay, tigrina, pampas cat, Andean cat, puma and jaguarundi. The samples were representative of a wide distribution of these species in Central and South America. Our analysis suggests either three or four colonization events from North America to South America over the past 3 Myr, followed by subsequent speciation events and the attainment of high or very high genetic diversity levels for seven of the species. No unique evolutionary process was detected for any of the current Neotropical cat species.

Genetic diversity and population structure for ocelots (Leopardus pardalis) in Costa Rica

Ocelots (Leopardus pardalis) are a wide-ranging felid species, occurring from southern United States to northern Argentina. They occupy various habitats and are usually considered the most abundant wild cat species in the Neotropics. However, genetic studies that include free-ranging Mesoamerican ocelots are rare and generally based on small sample sizes. This is the first conservation genetics study on ocelots in Costa Rica and the second one in Mesoamerica that has conducted a genetic assessment of the species at a countrywide scale. We evaluated genetic diversity and population structure of ocelots using 15 microsatellite loci in 28 successfully genotyped individuals from throughout the country. We also compared genetic diversity of Costa Rican ocelots with that of jaguars (Panthera onca) and pumas (Puma concolor) in the country, and with ocelots in Belize. Genetic diversity of ocelots in Costa Rica was relatively high as measured by rarified allelic richness (AR = 5.50 ± 1.36) and expected heterozygosities (HE = 0.79 ± 0.08). We did not detect patterns of genetic substructure, suggesting high levels of gene flow throughout the country and no strong barriers to movement. As expected, genetic diversity of Costa Rican ocelots was higher than co-occurring jaguars and pumas. Additionally, levels of genetic diversity were slightly higher in Costa Rican ocelots when compared with their counterparts in Belize, confirming the south to north decrease in genetic diversity reported in other studies. Our study provides critical baseline information to understand the status of wild ocelot populations in Costa Rica. Future studies on ocelots and other threatened or keystone species should also integrate genetic monitoring and conservation genetics analysis to properly inform management decisions, guarantee their long-term survival, and improve the resilience of ecosystems.

The jaguar's spots are darker than they appear: assessing the global conservation status of the jaguar Panthera onca

The IUCN Red List is widely used to guide conservation policy and practice. However, in most cases the evaluation of a species using IUCN Red List criteria takes into account only the global status of the species. Although subpopulations may be assessed using the IUCN categories and criteria, this rarely occurs, either because it is difficult to identify subpopulations or because of the effort involved. Using the jaguar Panthera onca as a model we illustrate that wide-ranging species that are assigned a particular category of threat based on the IUCN Red List criteria may display considerable heterogeneity within individual taxa in terms of the level of risk they face. Using the information available on the conservation status of the species, we evaluated the jaguar's current geographical range and its subpopulations. We identified the most threatened subpopulations, using the extent of occurrence, area of occupancy, population size and the level of threat to each subpopulation. The main outcome of this analysis was that although a large subpopulation persists in Amazonia, virtually all others are threatened because of their small size, isolation, deficient protection and the high human population density. Based on this approach, future conservation efforts can be prioritized for the most threatened subpopulations. Based on our findings we recommend that for future Red List assessments assessors consider the value of undertaking assessments at the subpopulation level. For the jaguar, sub-global assessments should be included on the Red List as a matter of urgency.

A Comparative Analysis of Genetic Diversity and Structure in Jaguars (Panthera onca), Pumas (Puma concolor), and Ocelots (Leopardus pardalis) in Fragmented Landscapes of a Critical Mesoamerican Linkage Zone

With increasing anthropogenic impact and landscape change, terrestrial carnivore populations are becoming more fragmented. Thus, it is crucial to genetically monitor wild carnivores and quantify changes in genetic diversity and gene flow in response to these threats. This study combined the use of scat detector dogs and molecular scatology to conduct the first genetic study on wild populations of multiple Neotropical felids coexisting across a fragmented landscape in Belize, Central America. We analyzed data from 14 polymorphic microsatellite loci in 1053 scat samples collected from wild jaguars (Panthera onca), pumas (Puma concolor), and ocelots (Leopardus pardalis). We assessed levels of genetic diversity, defined potential genetic clusters, and examined gene flow for the three target species on a countrywide scale using a combination of individual- and population-based analyses. Wild felids in Belize showed moderate levels of genetic variation, with jaguars having the lowest diversity estimates (HE = 0.57 ± 0.02; AR = 3.36 ± 0.09), followed by pumas (HE = 0.57 ± 0.08; AR = 4.20 ± 0.16), and ocelots (HE = 0.63 ± 0.03; AR = 4.16 ± 0.08). We observed low to moderate levels of genetic differentiation for all three target species, with jaguars showing the lowest degree of genetic subdivision across the country, followed by ocelots and pumas. Although levels of genetic diversity and gene flow were still fairly high, we detected evidence of fine-scale genetic subdivision, indicating that levels of genetic connectivity for wild felids in Belize are likely to decrease if habitat loss and fragmentation continue at the current rate. Our study demonstrates the value of understanding fine-scale patterns of gene flow in multiple co-occurring felid species of conservation concern, which is vital for wildlife movement corridor planning and prioritizing future conservation and management efforts within human-impacted landscapes.

Monitoring jaguar populationsPanthera oncawith non-invasive genetics: a pilot study in Brazilian ecosystems

The global population of jaguarsPanthera oncahas decreased significantly since the beginning of the 20th century. Given the scarcity of demographic and biological information, estimating population parameters is critical for the design of conservation measures. The jaguar's elusive behaviour makes it impossible to estimate and monitor populations by direct observation. We propose a non-invasive genetic sampling approach and demonstrate its potential for large-scale monitoring. Sex identification was optimized for faecal samples of jaguars and other felids. We also optimized a set of 11 microsatellite markers for reliable identification of individuals. We estimated the effectiveness of faecal sample genotyping in two distinct Brazilian biomes: the Pantanal and the semi-arid Caatinga. Almost 90% of the samples that were molecularly identified as jaguar (n = 90) were successfully genotyped and were assigned to 30 individuals. Genetic diversity was generally high but was significantly lower in the Caatinga population. We show that non-invasive genetic sampling can be a reliable tool to study population parameters and to monitor the genetic status of jaguar populations in different habitats. It may also be useful for future surveys of jaguars that address ecological, behavioural and conservation issues, and could provide a baseline for non-invasive genetic studies of other wild felid populations.

Panel of polymorphic heterologous microsatellite loci to genotype critically endangered Bengal tiger: a pilot study

In India, six landscapes and source populations that are important for long-term conservation of Bengal tigers (Panthera tigris tigris) have been identified. Except for a few studies, nothing is known regarding the genetic structure and extent of gene flow among most of the tiger populations across India as the majority of them are small, fragmented and isolated. Thus, individual-based relationships are required to understand the species ecology and biology for planning effective conservation and genetics-based individual identification has been widely used. But this needs screening and describing characteristics of microsatellite loci from DNA from good-quality sources so that the required number of loci can be selected and the genotyping error rate minimized. In the studies so far conducted on the Bengal tiger, a very small number of loci (n = 35) have been tested with high-quality source of DNA, and information on locus-specific characteristics is lacking. The use of such characteristics has been strongly recommended in the literature to minimize the error rate and by the International Society for Forensic Genetics (ISFG) for forensic purposes. Therefore, we describe for the first time locus-specific genetic and genotyping profile characteristics, crucial for population genetic studies, using high-quality source of DNA of the Bengal tiger. We screened 39 heterologous microsatellite loci (Sumatran tiger, domestic cat, Asiatic lion and snow leopard) in captive individuals (n = 8), of which 21 loci are being reported for the first time in the Bengal tiger, providing an additional choice for selection. The mean relatedness coefficient (R = -0.143) indicates that the selected tigers were unrelated. Thirty-four loci were polymorphic, with the number of alleles ranging from 2 to 7 per locus, and the remaining five loci were monomorphic. Based on the PIC values (> 0.500), and other characteristics, we suggest that 16 loci (3 to 7 alleles) be used for genetic and forensic study purposes. The probabilities of matching genotypes of unrelated individuals (3.692 × 10(-19)) and siblings (4.003 × 10(-6)) are within the values needed for undertaking studies in population genetics, relatedness, sociobiology and forensics.

Degree of landscape fragmentation influences genetic isolation among populations of a gliding mammal

Forests and woodlands are under continuing pressure from urban and agricultural development. Tree-dependent mammals that rarely venture to the ground are likely to be highly sensitive to forest fragmentation. The Australian squirrel glider (Petaurus norfolcensis) provides an excellent case study to examine genetic (functional) connectivity among populations. It has an extensive range that occurs in a wide band along the east coast. However, its forest and woodland habitat has become greatly reduced in area and is severely fragmented within the southern inland part of the species' range, where it is recognised as threatened. Within central and northern coastal regions, habitat is much more intact and we thus hypothesise that genetic connectivity will be greater in this region than in the south. To test this we employed microsatellite analysis in a molecular population biology approach. Most sampling locations in the highly modified south showed signatures of genetic isolation. In contrast, a high level of genetic connectivity was inferred among most sampled populations in the more intact habitat of the coastal region, with samples collected 1400 km apart having similar genetic cluster membership. Nonetheless, some coastal populations associated with urbanisation and agriculture are genetically isolated, suggesting the historic pattern observed in the south is emerging on the coast. Our study demonstrates that massive landscape changes following European settlement have had substantial impacts on levels of connectivity among squirrel glider populations, as predicted on the basis of the species' ecology. This suggests that landscape planning and management in the south should be focused on restoring habitat connectivity where feasible, while along the coast, existing habitat connectivity must be maintained and recent losses restored. Molecular population biology approaches provide a ready means for identifying fragmentation effects on a species at multiple scales. Such studies are required to examine the generality of our findings for other tree-dependent species.

Phylogeography, genetic structure and population divergence time of cheetahs in Africa and Asia: evidence for long-term geographic isolates

The cheetah (Acinonyx jubatus) has been described as a species with low levels of genetic variation. This has been suggested to be the consequence of a demographic bottleneck 10 000–12 000 years ago (ya) and also led to the assumption that only small genetic differences exist between the described subspecies. However, analysing mitochondrial DNA and microsatellites in cheetah samples from most of the historic range of the species we found relatively deep phylogeographic breaks between some of the investigated populations, and most of the methods assessed divergence time estimates predating the postulated bottleneck. Mitochondrial DNA monophyly and overall levels of genetic differentiation support the distinctiveness of Northern-East African cheetahs (Acinonyx jubatus soemmeringii). Moreover, combining archaeozoological and contemporary samples, we show that Asiatic cheetahs (Acinonyx jubatus venaticus) are unambiguously separated from African subspecies. Divergence time estimates from mitochondrial and nuclear data place the split between Asiatic and Southern African cheetahs (Acinonyx jubatus jubatus) at 32 000–67 000 ya using an average mammalian microsatellite mutation rate and at 4700–44 000 ya employing human microsatellite mutation rates. Cheetahs are vulnerable to extinction globally and critically endangered in their Asiatic range, where the last 70–110 individuals survive only in Iran. We demonstrate that these extant Iranian cheetahs are an autochthonous monophyletic population and the last representatives of the Asiatic subspecies A. j. venaticus. We advocate that conservation strategies should consider the uncovered independent evolutionary histories of Asiatic and African cheetahs, as well as among some African subspecies. This would facilitate the dual conservation priorities of maintaining locally adapted ecotypes and genetic diversity.

The effect of habitat fragmentation on the genetic structure of a top predator: loss of diversity and high differentiation among remnant populations of Atlantic Forest jaguars (Panthera onca)

Habitat fragmentation may disrupt original patterns of gene flow and lead to drift-induced differentiation among local population units. Top predators such as the jaguar may be particularly susceptible to this effect, given their low population densities, leading to small effective sizes in local fragments. On the other hand, the jaguar's high dispersal capabilities and relatively long generation time might counteract this process, slowing the effect of drift on local populations over the time frame of decades or centuries. In this study, we have addressed this issue by investigating the genetic structure of jaguars in a recently fragmented Atlantic Forest region, aiming to test whether loss of diversity and differentiation among local populations are detectable, and whether they can be attributed to the recent effect of drift. We used 13 microsatellite loci to characterize the genetic diversity present in four remnant populations, and observed marked differentiation among them, with evidence of recent allelic loss in local areas. Although some migrant and admixed individuals were identified, our results indicate that recent large-scale habitat removal and fragmentation among these areas has been sufficiently strong to promote differentiation induced by drift and loss of alleles at each site. Low estimated effective sizes supported the inference that genetic drift could have caused this effect within a short time frame. These results indicate that jaguars' ability to effectively disperse across the human-dominated landscapes that separate the fragments is currently very limited, and that each fragment contains a small, isolated population that is already suffering from the effects of genetic drift.

Microsatellite Analysis of the Spectacled Bear (Tremarctos ornatus) Across its Range Distribution

DNA samples of the spectacled bear (Tremarctos ornatus) from five Andean countries, Venezuela, Colombia, Ecuador, Peru and Bolivia, were analyzed for nine microsatellite loci. Seven of them were polymorphic, which led us to investigate several population-genetic parameters. Private alleles and significant differences in gene frequencies were found among the populations studied, which demonstrated the extent of genetic differentiation among the spectacled bear populations. The levels of gene diversity measured with these microsatellites were rather modest in this species. Hardy-Weinberg disequilibrium was especially found for the overall and the Ecuadorian samples, and might be due to the Wahl-und effect or consanguinity. Significant genetic heterogeneity was mainly observed among the Colombian and the Ecuadorian populations. Markov chain Monte Carlo simulations clearly showed that two different gene pools were present, one present in the Venezuelan-Colombian bears and other in the Ecuadorian ones.