Jaguar Populations Research Articles

Beyond words: From jaguar population trends to conservation and public policy in Mexico.

The jaguar (Panthera onca) is one of the most threatened carnivores in the Americas. Despite a long history of research on this charismatic species, to date there have been few systematic efforts to assess its population size and status in most countries across its distribution range. We present here the results of the two National Jaguar Surveys for Mexico, the first national censuses in any country within the species distribution. We estimated jaguar densities from field data collected at 13 localities in 2008–2010 (2010 hereafter) and 11 localities in 2016–2018 (2018 hereafter). We used the 2010 census results as the basis to develop a National Jaguar Conservation Strategy that identified critical issues for jaguar conservation in Mexico. We worked with the Mexican government to implement the conservation strategy and then evaluated its effectivity. To compare the 2010 and 2018 results, we estimated the amount of jaguar-suitable habitat in the entire country based on an ecological niche model for both periods. Suitable jaguar habitat covered ~267,063 km2 (13.9% of the country’s territory) in 2010 and ~ 288,890 km2 (~14.8% of the country’s territory) in 2018. Using the most conservative density values for each priority region, we estimated jaguar densities for both the high and low suitable habitats. The total jaguar population was estimated in ~4,000 individuals for 2010 census and ~4,800 for the 2018 census. The Yucatan Peninsula was the region with the largest population, around 2000 jaguars, in both censuses. Our promising results indicate that the actions we proposed in the National Jaguar Conservation Strategy, some of which have been implemented working together with the Federal Government, other NGO’s, and land owners, are improving jaguar conservation in Mexico. The continuation of surveys and monitoring programs of the jaguar populations in Mexico will provide accurate information to design and implement effective, science-based conservation measures to try to ensure that robust jaguar populations remain a permanent fixture of Mexico’s natural heritage.

Jaguars from the Brazilian Pantanal: Low genetic structure, male-biased dispersal, and implications for long-term conservation

Habitat loss and fragmentation are important threats to carnivores worldwide and are especially intense for large predators. Jaguars have been extirpated from over half of their original distribution, and few regions still maintain large populations. The Pantanal is among the best examples of such regions and can be used to better understand several aspects of jaguar biology that are relevant for conservation planning throughout the species' range. Thus, in this study we used microsatellite markers and field data to: (i) assess the genetic structure and gene flow of jaguars ( n = 110) from the northern and southern Pantanal; (ii) verify if females are more philopatric than males; (iii) produce a timeline pedigree to allow the identification of distances from offspring to their mothers; and (iv) estimate the generation time for jaguars. Our results are consistent with the hypothesis that Pantanal jaguars represent a panmictic population, although exhibiting some degree of local differentiation. The Paraguay River seems to be an important factor promoting gene flow among the studied populations, highlighting its relevance for regional conservation efforts. Our data provide the first genetic evidence of female philopatry and male-biased dispersal in jaguars. In addition, we report the first timeline pedigree for a wild jaguar population and the first direct estimate of the species' generation time. Our results contribute to the construction of more realistic assessments of jaguar population dynamics and long-term genetic viability, thus contributing to the design of improved conservation strategies on behalf of this species.

Detection of Jaguar (Panthera onca) From Genetic Material in Drinking Water

Jaguar (Panthera onca) are of conservation concern and occur at very low densities in the northern portion of their range in northern Mexico and the southwestern United States. Environmental DNA sampling to detect genetic material from drinking water may be an effective approach for jaguar detection in these arid landscapes. Here we develop a qPCR assay for the detection of jaguar mitochondrial DNA, show that large quantities of DNA (mean 66,820 copies/L) can be found in the drinking water of captive animals, and observe detectable levels of DNA (80 copies/L) in a wild habitat with known jaguar populations. We suggest that environmental DNA sampling may represent a useful, complementary sampling tool for detection of rare jaguars, although effective application would require careful consideration of DNA persistence time in the environment.

Is reintroduction a tool for the conservation of the jaguarPanthera onca? A case study in the Brazilian Pantanal

AbstractTo evaluate the feasibility of reintroduction as a tool for conservation of the jaguarPanthera onca, we adapted the IUCN soft release protocol to reintroduce two jaguars in the southern Pantanal, Brazil. After being kept at rescue centres for 13 months, the jaguars were moved to a 1-ha enclosure with native vegetation on a 53,000 ha ranch in the Pantanal, where hunting is not allowed and prey is abundant. In the enclosure, the animals were fed with meat, dead animals (roadkill) and then, progressively, live wild prey. After 11 months, the jaguars were fitted with collars equipped with GPS/VHF (recording one location per hour) and accelerometers, and released in the same area. The animals established residence near the enclosure, with home ranges, movement parameters, daily activity patterns and prey consumption similar to that recorded in previous studies. Social interaction and reproduction indicated the reintroduction was successful, and that it can be a tool for the species' survival in areas where the jaguar population is in decline.

Visitation patterns of jaguars Panthera onca (Carnivora: Felidae) to isolated water ponds in a tropical forest landscape

Jaguar populations have declined dramatically in the last century. The Maya Biosphere Reserve (MBR) within the Selva Maya (SM) is a priority area for jaguar conservation. Influential factors in the jaguar seasonal distribution include the availability of surface water in wetlands such as the “aguadas” and the availability of prey. Aguadas are formed by isolated depressions in the landscape and serve as a water supply for wildlife during dry periods. The goal of this study was to describe the visitation patterns of jaguars to aguadas in a Tropical forest at Dos Lagunas Protected Biotopo, a core zone of the MBR, Guatemala. We used camera-trap data from seven aguadas during the dry seasons 2014-2017. We determined visitation rates (VR, records for 1,000 trap-days) and activity patterns (AP) of jaguars for all years, aguadas, and sexes. We tested for significant differences in AP between sexes, and we estimated the coefficient of overlap (D) for female and male jaguar activity. We recorded 14 individuals (five females, eight males, and one unsexed) in 60 visit events. Jaguars have significant more diurnal activity at aguadas, and showed a VR = 13.1 for 1,000 trap-days. VR varied between aguadas (VR = 9.5 – 19.4), years (VR = 1.9 – 39.2) and sexes (VR = 6.1 for females and 5.5 for males). We did not find significant differences in the AP of female and male jaguars (P > 0.05). The coefficient of overlap between activity of females and males was D = 0.77 (95 % confidence interval: 0.70 to 0.84; P > 0.05). Aguadas may represent regular sites of jaguar home-ranges overlap for the important resources they provide for wildlife during the dry season. Aguadas could play an important role in the conservation and management of jaguar populations since the spatial distribution of these bodies of water is scattered, but ecologically important for jaguars within the MBR and the SM. Aguadas also, are important landscape features that could influence the spatial interactions of individuals. We encourage jaguar researchers to increase investigation on jaguars visiting aguadas and other wetlands in the SM to better understand the jaguar activity patterns and sex-specific habitat requirements.

DENTAL DISEASES AND OTHER ORAL PATHOLOGIES OF CAPTIVE JAGUARS (PANTHERA ONCA) FROM BELIZE, CENTRAL AMERICA.

Dental and oral diseases are prevalent in many mammalian species including wild felids. Determining the dental and oral health status of captive animal populations can help establish preventive and therapeutic strategies, leading to improved welfare and conservation efforts. The aim of this study was to assess the prevalence of periodontal disease, endodontic disease, tooth resorption, and other clinically relevant dental and maxillofacial abnormalities in a population of captive jaguars (Panthera onca) using clinical, radiographic, and histopathological findings. Fifteen jaguars, ranging from young adult to geriatric, kept at a private zoo in Belize, Central America, had a detailed oral examination under general anesthesia between January 2015 and March 2019. Periodontitis was present in 3.8% (16/423) of examined teeth and 53.8% (7/13) of jaguars that underwent periodontal probing. Endodontic disease secondary to dentoalveolar trauma was found in 21.0% (89/423) of teeth in 73.3% (11/15) of animals. Tooth resorption, which has not been previously documented in jaguars, affected 1.4% (6/423) of teeth in 13.3% (2/15) of jaguars. Other abnormalities included metallic foreign material (gunshot) identified radiographically in 33.3% (5/15) of jaguars and nontraumatizing malocclusion in 9.1% (1/11) of jaguars that had occlusion evaluated. Much of the oral pathology identified in captive jaguars is suspected to arise from capture and/or captivity-associated behaviors, as suggested by gunshot around the oral cavity, fractures of rostral teeth (canine and incisor teeth), and abrasions consistent with cage-biting on canine teeth. Anesthetized oral examination-including full-mouth intraoral radiographs, periodontal probing, and charting-is recommended for jaguars with clinical signs of oral pain, as well as for routine systemic evaluation.

Comparative effect of cryoprotectant combinations on the conservation of somatic cells derived from jaguar, Panthera onca, towards the formation of biologic banks.

Due to the reduction of the jaguar population, the formation of somatic cell cryobanks represents an interesting tool for its conservation. Nevertheless, the success of these cryobanks depends on the cryoprotectants used in cryopreservation. We evaluated the effects of the intracellular cryoprotectants (10% dimethyl sulfoxide, DMSO; 10% ethylene glycol, EG) in the absence or presence of an extracellular cryoprotectant (0.2 M sucrose, SUC) on the morphology, confluence, viability, and metabolism of somatic cells derived from five jaguars belonging to Brazilian zoos. The morphology was presented in a descriptive manner, while the confluence, viability and metabolic activity were presented as means and compared using statistical tests. Non-cryopreserved cells were used as control and compared to frozen/thawed cells using cryoprotectants. No difference was observed for the morphology and confluence among non-cryopreserved and cryopreserved cells, regardless of the cryoprotectants. Only cryopreserved cells in EG (45.8%±12.9) had a reduction in their viability when compared to non-cryopreserved cells (97.8%±1.1). Only cryopreserved cells in DMSO with SUC (76.0%±2.7) or absence of SUC (77.0%±3.7) maintained their metabolic activity after thawing, when compared to non-cryopreserved cells (100.0%±6.7). Therefore, combinations of DMSO in the absence and presence of SUC were efficient in the cryopreservation of somatic cells of jaguars.

Jaguar (Panthera onca) density and tenure in a critical biological corridor.

We estimated jaguar density and tenure, and investigated ranging behavior, using camera traps across the Maya Forest Corridor, a human-influenced landscape in central Belize that forms the only remaining connection for jaguar populations inhabiting two regional forest blocks: the Selva Maya and the Maya Mountain Massif. Jaguars were ubiquitous across the study area. Similar to the neighboring Selva Maya, mean density ranged from 1.5 to 3.1 jaguars per 100 km2, estimated by spatial capture-recapture models. Cameras detected almost twice as many males as females, probably reflecting detection bias, and males ranged more widely than females within the camera grid. Both sexes crossed two major rivers, while highway crossings were rare and male-biased, raising concern that the highway could prevent female movement if traffic increases. Jaguars were more transient where the landscape was fragmented with settlements and agriculture than in contiguous forest. Compared with jaguars in the protected forests of the Maya Mountains, jaguars in central Belize displayed a lower potential for investment in intraspecific communication, indicative of a lower quality landscape; however, we did detect mating behavior and juveniles. Tenure of individuals was shorter than in the protected forests, with a higher turnover rate for males than females. At least three-quarters of reported jaguar deaths caused by people were male jaguars, and the majority was retaliation for livestock predation. Jaguars seem relatively tolerant to the human-influenced landscape of central Belize. However, intensification of game hunting and lethal control of predators would threaten population persistence, while increased highway traffic and clear-cutting riparian forest would severely limit the corridor function. Our results show that the viability of the corridor, and thus the long-term survival of jaguar populations in this region, will depend on appropriate land-use planning, nonlethal control of livestock predators, enforcement of game hunting regulations, and wildlife-friendly features in future road developments.

Anthropogenic factors disproportionately affect the occurrence and potential population connectivity of the Neotropic’s apex predator: The jaguar at the southwestern extent of its distribution

Maintaining population connectivity is an important component of jaguar (Panthera onca) conservation. However, the effectiveness of connectivity corridors can be affected by anthropogenic factors. At the southwestern limit of the jaguar’s current distribution in the Yungas and Dry Chaco ecoregions, connectivity among jaguar populations has been compromised by extensive deforestation. The extent that jaguars and their prey are using corridors in the region, and the factors that determine their use, however, has not been evaluated. We sampled 105 sites in 7 study areas in connectivity corridors in the Yungas and Dry Chaco ecoregions of Argentina, Bolivia, and Paraguay for jaguars and six large-bodied principal prey species through interviews with inhabitants and land owners. Using a multi-species community occupancy modeling framework, we examined species occurrence in relation to forest cover and anthropogenic factors. All species were positively associated with increasing forest cover, decreasing number of homesteads, and increasing distance from roads and settlements, with jaguar occurrence most strongly negatively correlated with anthropogenic factors. Mean conditional occupancy of jaguars was high (>75%) in only two study areas, while only two study areas had mean conditional occupancy estimates of jaguars that were consistent with prey occurrence, with other sites having lower jaguar occurrence than expected. Despite high levels of forest cover and sufficient prey availability, the lower than expected jaguar occurrence in most study areas suggests that illegal killing is likely a principal factor determining jaguar occurrence. The probability of site use by jaguars in most study areas was low, and consequently, functional connectivity is reduced in those areas and likely throughout the region. Our findings have range-wide implications for jaguar conservation since we show that despite sufficient habitat and prey availability, jaguar populations are likely reduced or extirpated by illegal killing driven by jaguar-ranching conflict, cultural norms, or fear.

Jaguars and Roads in the Calakmul Region: Evidence of Road Crossing and Collisions with Vehicles

Jaguars (Panthera onca) suffer from the negative effects of roads, mostly significant habitat fragmentation and increased risk of mortality due to vehicle collisions. In Mexico records of jaguars killed on roads are scarce and mostly anecdotal. The Calakmul-Balam-Ku jaguar population is the most important jaguar population in Mexico, but it is threatened by an extensive road network in which Federal Highway 186 Escarcega–Chetumal (hereafter called Hwy. 186) serves as the main road in the region. As part of a study to determine the diversity and abundance of medium- and large-sized mammals around Hwy. 186, we set 47 camera traps during 2019 and obtained pictures of 2 male jaguars on both sides of the road, evidence that these animals were crossing the highway. Also, later in 2020 we found the road-killed carcass of one the jaguars that we had previously documented crossing the highway. These empirical observations occurred in areas where landscape models implemented as far back as 2010 had predicted jaguar crossing sites on Hwy. 186 and where wildlife-safe road-crossing infrastructure has been proposed but so far not installed.

Effectiveness of protected areas for jaguars: the case of the Taiamã Ecological Station in Brazil

The largest feline in the Americas and the third largest in the world, the jaguar is an apex predator in the food chain and a key species in the ecosystems where it occurs, developing important ecological functions in maintaining ecosystem balance. In Brazil, the Pantanal is considered an important refuge for the species, and protected areas such as the Taiamã Ecological Station (TES) are relevant for conservation of pristine ecosystem where the species persist. Thus, considering that this area is located in one of the regions with the highest concentration of this large cat in the Pantanal, the objective of this study was to evaluate the effectiveness of the protection given by the TES for the jaguar population. The station is a flooded island in the middle of the Paraguay river and surrounded by extensive wetlands. We monitored ten jaguars using GPS collar at the TES and its surroundings. The samples were separated into high-water season (January to June) and low-water season (July to December), and the estimated home ranges were grouped as: 1) residents only and 2) all monitored individuals. The stabilization of the home ranges of eight jaguars, considered residents, was determined through variograms. When all jaguars were analysed together there was 55% overlap between the clustered areas of the two analysed seasons. In the analysis excluding non-resident individuals there was 72% overlap between the clustered areas. The type of land cover inside these areas was very similar between these periods. The range of this protected area is not sufficient to effectively protect these jaguar populations, since the grouped home ranges of the resident animals studied are 3.5(wet)/2.5(dry) times larger than the area of the TES. However, the surroundings of the TES have low human impact and no deforestation and, in this way, the landscape context of the station may have a significant effect on the persistence of a large carnivore like the jaguar. However, it is necessary to create more protected areas in order to prevent possible future environmental changes in the areas surrounding TES.

A stochastic model of jaguar abundance in the Peruvian Amazon under climate variation scenarios.

The jaguar (Panthera onca) is the dominant predator in Central and South America, but is now considered near‐threatened. Estimating jaguar population size is difficult, due to uncertainty in the underlying dynamical processes as well as highly variable and sparse data. We develop a stochastic temporal model of jaguar abundance in the Peruvian Amazon, taking into account prey availability, under various climate change scenarios. The model is calibrated against existing data sets and an elicitation study in Pacaya Samiria. In order to account for uncertainty and variability, we construct a population of models over four key parameters, namely three scaling parameters for aquatic, small land, and large land animals and a hunting index. We then use this population of models to construct probabilistic evaluations of jaguar populations under various climate change scenarios characterized by increasingly severe flood and drought events and discuss the implications on jaguar numbers. Results imply that jaguar populations exhibit some robustness to extreme drought and flood, but that repeated exposure to these events over short periods can result in rapid decline. However, jaguar numbers could return to stability—albeit at lower numbers—if there are periods of benign climate patterns and other relevant factors are conducive.

Reserve size, dispersal and population viability in wide ranging carnivores: the case of jaguars in Emas National Park, Brazil

AbstractProtected areas may be important refuges for large carnivores, but many are not large enough to sustain viable populations. Without sufficient dispersal between protected areas, large carnivore populations inside them are at risk of becoming genetically isolated and demographically vulnerable. In this study, we use the jaguar population in and around Emas National Park in the Brazilian Cerrado as a case study to evaluate the demographic sustainability of a large carnivore population within a small and potentially isolated protected area. We used camera trapping data and spatially explicit capture‐recapture models to estimate density and corresponding population size of jaguars in Emas National Park. We then used a matrix‐based age and sex structured stochastic population model to evaluate the demographic viability of jaguar populations across a range of population sizes, including those estimated for Emas. We detected 10 individual jaguars during our survey with a total of 74 detections. Our density estimation became unbiased using a buffer width of 30 km and produced a density of 0.17 jaguars per 100 km2. The estimated population sizes of 10–60 animals suffered extinction risks of 70–90% without net immigration. However, only a low number of immigrants were required to suppress extinction risk towards zero. Our density estimate for jaguars was lower than in previous studies, and our simulations suggested that this population may have a substantial extinction risk. Ensuring dispersal and connectivity outside of protected areas, through the implementation of habitat corridors, can greatly reduce this extinction risk, and we suggest that this scenario is potentially applicable to many other large carnivore populations.

Abundance of jaguars and occupancy of medium- and large-sized vertebrates in a transboundary conservation landscape in the northwestern Amazon

Large-scale transboundary conservation initiatives are necessary to respond to threats against tropical forests, and the jaguar (Panthera onca), a flagship and umbrella species in the Neotropics, is an ideal target species for such initiatives. We estimated jaguar abundance and occupancy of medium- and large-sized mammals and birds across a transboundary landscape in the northwestern Amazon biome using camera-trap data from 168 stations; specifically within three management regimes of indigenous and protected lands in Colombia (the indigenous reserve of Umancia), Ecuador (Cuyabeno Wildlife Reserve), and Peru (Güeppi-Sekime National Park). Based on spatial capture-recapture models, we estimated jaguar density in the study area at 2.20 ± 0.44 individuals per 100 km2, implying an abundance of 322 jaguars (95% CI = 217–477). These estimates suggest that an entire mega-landscape, which also includes other protected areas and indigenous lands, could harbor as many as 2000 jaguars (95% CI = 1586–3498). We found that jaguar abundance and medium-to large-sized terrestrial vertebrate species richness (totaling 24 mammals and 4 birds) were similar under the three management regimes. Overall, our study indicates that a significant healthy population of jaguars can survive in this large-scale conservation corridor that crosses country borders, a place where protected areas and indigenous territories are key. This study is among the first to take a transboundary approach for jaguar conservation in a protected but still threatened part of the Amazon biome, inhabited by several ancient indigenous people. As a large forest block, this conservation landscape serves not only as an effective buffer against deforestation and a stronghold for jaguar populations and medium- and large-sized vertebrates, but it also secures the well-being of local people.

Large-scale assessment of genetic diversity and population connectivity of Amazonian jaguars (Panthera onca) provides a baseline for their conservation and monitoring in fragmented landscapes

Jaguar population genetics has so far not been investigated on a broad scale in the Amazon rainforest, which constitutes the largest remaining block of continuous habitat for the species. Given its size, it serves not only as a stronghold but also as a reference for jaguar conservation genetics, against which fragmented landscapes can be compared. We assessed genetic diversity and population structure of Amazonian jaguars using 11 microsatellite loci and performed comparative analyses incorporating available data from two other South American biomes (Pantanal and Atlantic Forest) in which the species has faced different amounts of habitat loss and fragmentation. Using the largest genetic data set assembled to date for jaguars (n = 190), we observed that all diversity indices were consistently higher for the Amazonian population, with no genetic subdivision detected in that region, indicating large-scale connectivity across >3000 km. In contrast, we corroborate the inference of anthropic-driven genetic structure and bottlenecks for two Atlantic Forest populations. Our results indicate that the Amazon is a critically important stronghold for jaguars, comprising a highly diverse, panmictic population that allows a glimpse into the patterns of genetic connectivity that characterized this species prior to human intervention. In contrast, the Atlantic Forest populations jointly still retain considerable levels of genetic diversity, but this is currently partitioned among isolated fragments that are increasingly subjected to heavy anthropic disturbance. These results have important implications for jaguar conservation planning, highlighting the critical condition of Atlantic Forest populations and providing a genetic baseline to which they can be compared.

Coexistence of jaguars (Panthera onca) and pumas (Puma concolor) in a tropical forest in south–eastern Mexico

The biological ranges of the jaguar (Panthera onca) and puma (Puma concolor) overlap in the Yucatan Peninsula, corresponding to the most important population of jaguars in Mexico. The goal of this study in the El Eden Ecological Reserve (EER) was to investigate the factors that permit these two predators to coexist in the dense vegetation of medium–stature tropical forest and secondary forest in the north–eastern Yucatan Peninsula. We assessed their spatial and temporal overlap using Pianka’s index, and evaluated their habitat use by applying occupancy models. A total sampling effort of 7,159 trap–nights over 4 years produced 142 independent photographic records of jaguars, and 134 of pumas. The felids showed high to very high overlap in their use of different vegetation (0.68–0.99) and trail types (0.63–0.97) and in their activity patterns (0.81–0.90). However, their peak activity patterns showed some temporal separation. Time of day, particularly for peak activity time, was the best predictor to explain the coexistence of the felids in this habitat. While occupancy models showed that the presence of potential prey species and vegetation type could predict the presence of felids in the study area. Natural disturbances during 2010 (hurricane) and 2011 (fire) drastically changed habitat use and activity patterns, resulting in pumas and jaguars adjusting their resource–use and activity pattern through a strategy of mutual evasion.

Puberty and oestral cycle length in captive female jaguars Panthera onca.

Habitat loss and fragmentation have been leading jaguars to constant conflicts with humans, and as a result, jaguar populations have been declining over the last decades. Captive breeding is often a tool for species conservation, and it is not different for jaguars. However, success is far from optimal due to the lack of basic knowledge about species’ reproductive biology. In the present study, we assessed gonadal hormonal profiles of natural oestral cycles and puberty and compared our data to those of other wild felids. We collected faecal samples from two to seven times per week for 18 months from two adults and three pre-pubertal females. We defined baseline levels for progestins and oestrogens in order to estimate oestrous cycle length and age at puberty. We compared our data with 16 other species through generalized linear model, using weight and genus as two explanatory variables. Cycle length was 38.28 ± 2.52 days, ranging from 25 to 44 days, while sexual maturity was attained within 22 months. Due to our analysis of both hormonal and behavioural data, there is a variation between this research from other studies that employed only behavioural observations. Such difference may be caused by the absence of behavioural oestrous at the peri-pubertal period. When compared to wild felids of similar size, puberty and oestral cycle durations of the jaguar females fell within the same range. Our modelling showed that age at maturity was influenced mostly by size and only Leopardus partially explained the observed variation. Conversely, oestral cycle length did not differ among genera or size categories. Our study adds to the body literature in the reproductive endocrinology of wild felids, and because female gametes are more challenging to collect and preserve, a strong understanding on the female reproductive physiology is essential to assisted reproduction and wild population viability assessment.

Population genetic structure and habitat connectivity for jaguar (Panthera onca) conservation in Central Belize

BackgroundConnectivity among jaguar (Panthera onca) populations will ensure natural gene flow and the long-term survival of the species throughout its range. Jaguar conservation efforts have focused primarily on connecting suitable habitat in a broad-scale. Accelerated habitat reduction, human-wildlife conflict, limited funding, and the complexity of jaguar behaviour have proven challenging to maintain connectivity between populations effectively. Here, we used non-invasive genetic sampling and individual-based conservation genetic analyses to assess genetic diversity and levels of genetic connectivity between individuals in the Cockscomb Basin Wildlife Sanctuary and the Maya Forest Corridor. We used expert knowledge and scientific literature to develop models of landscape permeability based on circuit theory with fine-scale landscape features as ecosystem types, distance to human settlements and roads to predict the most probable jaguar movement across central Belize.ResultsWe used 12 highly polymorphic microsatellite loci to identify 50 individual jaguars. We detected high levels of genetic diversity across loci (HE = 0.61, HO = 0.55, and NA = 9.33). Using Bayesian clustering and multivariate models to assess gene flow and genetic structure, we identified one single group of jaguars (K = 1). We identified critical areas for jaguar movement that fall outside the boundaries of current protected areas in central Belize. We detected two main areas of high landscape permeability in a stretch of approximately 18 km between Sittee River Forest Reserve and Manatee Forest Reserve that may increase functional connectivity and facilitate jaguar dispersal from and to Cockscomb Basin Wildlife Sanctuary. Our analysis provides important insights on fine-scale genetic and landscape connectivity of jaguars in central Belize, an area of conservation concern.ConclusionsThe results of our study demonstrate high levels of relatively recent gene flow for jaguars between two study sites in central Belize. Our landscape analysis detected corridors of expected jaguar movement between the Cockscomb Basin Wildlife Sanctuary and the Maya Forest Corridor. We highlight the importance of maintaining already established corridors and consolidating new areas that further promote jaguar movement across suitable habitat beyond the boundaries of currently protected areas. Continued conservation efforts within identified corridors will further maintain and increase genetic connectivity in central Belize.

Influence of different extenders on morphological and functional parameters of frozen-thawed spermatozoa of jaguar (Panthera onca)

Due to the global decrease in jaguar population, conservation strategies are essential and the development of effective semen cryopreservation protocols would contribute to the formation of germplasm banks. Therefore, the objectives were to (1) evaluate the use of TRIS and ACP-117c extenders for jaguar semen freezing, (2) describe the ultrastructural changes in sperm after cryopreservation, and (3) evaluate the binding capacity of the thawed sperm. Eight ejaculates from five mature individuals were collected by electroejaculation, extended in TRIS or a coconut based-extender (ACP-117c), and frozen in liquid nitrogen. Samples were evaluated for sperm motility, vigor, membrane functionality, mitochondrial activity, morphology (using light microscopy, scanning electron microscopy - SEM and transmission electron microscopy - TEM), sperm kinetic parameters (by computerized analysis - CASA), and sperm binding capability using an egg yolk perivitelline membrane assay. Samples preserved in TRIS presented better post-thaw motility (46.0 ± 7.7%) and membrane functionality (60.5 ± 4.2%) and higher mitochondrial activity (21.5 ± 3.7%) than those preserved in ACP-117c (20.9 ± 5.4% motile sperm; 47.1 ± 2.5% functional membrane; 11.8 ± 1.7% mitochondrial activity). Regarding ultrastructural evaluations, SEM showed that both extenders were able to preserve the superficial membrane of the sperm, but TEM revealed the occurrence of nuclear electron lucent points, especially in samples extended in ACP-117c. Additionally, TRIS also provided a higher number of sperm bound to the perivitelline membrane (29.5 ± 3.3%) in comparison to samples diluted in ACP-117c (18.6 ± 1.5%). Overall, we suggest the use of a TRIS-based extender for cryopreservation of jaguar semen.

Jaguar density in a mosaic of disturbed/preserved areas in southeastern Mexico

Jaguar populations in Mexico have been extensively reduced to the point where the species is considered Endangered. In south-eastern Mexico, jaguar density estimations have focused in the largest Jaguar Conservation Units (JCUs) but are lacking for the small, isolated JCUs where natural habitats are usually combined with farming areas. We installed 103 camera trap stations across an area in the small and isolated JCU of Laguna de Terminos and estimated the jaguar density using spatially explicit capture-recapture (SECR) models with the sex of the identified jaguars as a covariate. We obtained 126 pictures of adult jaguars in 7052 camera trap days, corresponding to seven females, seven males and three individuals of unidentified sex. We estimated a density of 1.934 ± 0.529 jaguars/100 km2. Our jaguar density estimation was in the lower range of those reported elsewhere in preserved areas of south-eastern Mexico, probably because habitat quality has been reduced by agriculture and cattle grazing.