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Ocelot density and habitat use in Tamaulipan thornshrub and tropical deciduous forests in Northeastern México
Abstract
Northeastern México is one of the most diverse regions in the country with high mammal richness. This region also sits on the northern periphery of the geographic distribution of ocelots (Leopardus pardalis), which are listed as endangered in México. Ocelot ecology in northeastern México is poorly known at local and landscape levels, especially in the ecologically rich temperate sierras, a perceived stronghold for ocelots. We used an occupancy approach to estimate ocelot-habitat use in Tamaulipan thornshrub and tropical deciduous forests and a spatially explicit capture–recapture (SECR) framework to estimate density of ocelots in the northern edge of the Sierra Tamaulipas, México. From May to December 2009, we conducted two camera trap surveys (summer: 20 camera stations; fall: 58 camera stations) on Rancho Caracol and Rancho Camotal, north of the Rio Soto de La Marina. We found ocelot detections were higher in areas with increasing patch density of tropical deciduous forest and habitat use was greater in Tamaulipan thornshrub and tropical deciduous forests with lower edge densities. Ocelot densities varied by sex, with females achieving greater densities (7.88 ocelots/100 km2 [95% CI: 4.85–12.81]) than males (3.81 ocelots/100 km2 [95% CI: 1.96–7.43]). Ocelots were averse to areas with high densities of edge cover in each woody community, supporting the notion of a forest patch interior species. Despite the study occurring 11 years ago, population densities were also among the highest reported in México using spatially explicit capture–recapture methods. The high ecological integrity of the habitat within the Sierra de Tamaulipas, recent protection as a Biosphere Reserve, and remote rugged terrain suggest long-term security of the ocelot population in this region.
... (Fernández 2001, Rocha et al. 2016, Monterrubio-Rico et al. 2018, Greenspan et al. 2020, Lombardi et al. 2022. Although across its range, the ocelot is considered by the IUCN to be a species of 'Least Concern' (Paviolo et al. 2015), it is listed as endangered in the USA (USFWS 1982) and Mexico (SEMARNAT 2010).Ocelot research in the binational northeasternmost portion of its range has primarily been conducted in the USA. ...
... In Texas, ocelots have been the focus of many detailed ecological studies (Harveson et al. 2004, Haines et al. 2005, 2006b, Janečka et al. 2007, Sternberg & Mays 2011, Schmidt et al. 2020, Lehnen et al. 2021, the findings of which suggest that in this region, ocelots can be considered fragmentation-intolerant habitat specialists. Literature on the distribution and characteristics of ocelot populations roughly 200 km south in the state of Tamaulipas, Mexico, a neighbor state to Texas, USA, remains scant (Ocañas-García et al. 2018, Lombardi et al. 2022. The ocelot's current range in Mexico includes the northeastern states of Nuevo León and Tamaulipas (Velazco-Macías & Peña-Mondragón 2015, García-Bastida et al. 2016, Caso & Dominguez 2018. ...
... In that study, ocelots demonstrated a significant preference for tropical deciduous forest relative to open habitats. Lombardi et al. (2022) estimated the density to be 11.69 ocelots per 100 km 2 using spatial capture− recapture (SCR) techniques from the same study area within a similar timeframe to Carvajal-Villarreal (2016). This study found that ocelots preferentially used tropical deciduous forest patches that afforded more interior cover, as measured by patch edge length relative to total patch area. ...
Although the ocelot Leopardus pardalis is listed as endangered in the USA and Mexico, research on the characteristics of ocelot populations in northeastern Mexico has been limited. Effective conservation strategies in this binational region can benefit from additional information on the distribution and status of these populations. We estimated ocelot abundance and density using capture-recapture data from remote cameras at 2 locations in Tamaulipas: 1 inland site near the Sierra Tamaulipas and 1 coastal site along the Laguna Madre. The inland site was sampled in 2013 with 32 camera stations, and estimated densities (mean ± SE ocelots per 100 km ² ) using non-spatial and spatial modeling approaches were 17.57 ± 1.10 and 28.19 ± 6.81, respectively. The coastal site was sampled in 2017 with 16 camera stations, and estimated densities using non-spatial and spatial modeling approaches were 59.03 ± 2.32 and 43.24 ± 7.24, respectively. These are the first published ocelot densities for these locations, and these sites represent the closest known populations to those in Texas, USA. The ocelot populations surveyed appear to be robust, with estimated abundances similar to or greater than other areas surveyed within the state of Tamaulipas. Future work should monitor the long-term status and connectivity of these and other nearby populations to inform management actions to ensure their continued existence, as well as to assess whether they could serve as suitable sources for the translocation of individuals into existing populations in need of genetic rescue in Texas.
... Plant species composition of the tropical deciduous forest included mauto (Loma divaricata), gumbo limbo (Bursera simaruba), mahuira (Phoebe tampicensis), and ebony (Ebanopsis ebano; Martin et al., 1954, Cram et al., 2006. In lower elevations, vegetation communities were composed of Tamaulipan thornshrub communities (sic Tamaulipan Mezquital) characterized by honey-mesquite (Prosopis glandulosa), huisache (Celtis pallida), blackbrush (Acacia rigidula), skeleton-leaf goldeneye (Viguiera stenoloba), and cenizo (Leucophyllum frutescens) (Cram et al. 2006;Lombardi et al., 2022a). ...
... A combination of WildView® Xtreme (Stealth Cam, LLC, Grand Prairie, TX) and Cuddeback® Capture 3 (Nontypical Inc, Green Bay, WI) was used at each camera station, with 1-2 camera traps per station (summer: 23; fall: 20; winter: 27) offset 1-2 m apart to aid in individual felid identification. Cameras were deployed along native game trails, near water guzzlers, and along earthen ranch roads within Tamaulipan thornshrub tropical deciduous (sic: tropical dry) forests, and mesquite-huisache woodlands (Stasey, 2012;Carvajal, 2016;Lombardi et al., 2022a). Camera settings and set-up were standardized across surveys (i.e., 30 s delay, active 24 hr, and attached to wooden stakes or trees 0.5 m above ground). ...
... Before this study, margays had yet to be documented in this part of Tamaulipas outside of El Cielo Biosphere Reserve, 100 km to the southwest (Alvarez, 1963;Carvajal et al., 2012). Margays are typically tied to large, forested areas (Harmsen et al., 2021) and low observations may be linked to high local densities of ocelots (Carvajal et al., 2012;Carrera-Treviño et al., 2018;Lombardi et al., 2022a). Although we used a smaller study design than typically used for jaguars (Ceballos et al., 2021a), we observed > 100 independent detections of jaguars (9 individuals; Carvajal, 2016), which was more than reported by Ceballos et al. (2021aCeballos et al. ( , 2021b for the national jaguar census for this area. ...
Studying interspecific interactions and community composition within carnivore guilds are often difficult to complete and is seldom done in North America. Here we used a historic camera trap database from 2009 to 2010 to describe the carnivore diversity and investigate the temporal niche partitioning of community members within the northern edge of the Sierra of Tamaulipas, México. We detected 15 different species of carnivores including six Felids, three Mephitids, as well as two Canids, Mustelids, and Procyonids each. In our diel activity analysis, we observed significant differences in diel activity between jaguars (Panthera onca) and mesocarnivores including ocelots (Leopardus pardalis), jaguarundis (Puma yagouroundi), and gray foxes (Urocyon cinereoargenteus). Ocelots, gray foxes, and white-nosed coatimundis (Nasua narica) had the highest occupancy rates across the study. Difficulty to understand temporal interactions between bobcats (Lynx rufus), pumas (Puma concolor), margay (Leopardus wiedii), coyote (Canis latrans), badgers (Taxidea taxus), three species of skunks (Mephitis sp; Conepatus sp.; Spilogale sp.), and long–tailed weasel (Neogale frenata) may have been related to habitat use, activity, low local populations, or reclusive behavior. This study illustrates the ecologically rich Sierra of Tamaulipas holds a diverse carnivore community and there is a need for continued monitoring to further understand the dynamics within this ecosystem.
... The ocelot is a forest species (Harveson et al. 2004;Jackson et al. 2005;Haines et al. 2006) that can use multiple habitats depending on availability (De Oliveira et al. 2010;Fusco-Costa et al. 2010), including disturbed and undisturbed habitats (Kolowski and Alonso 2010), although it prefers areas with closed canopy and dense vegetation (López-González et al. 2003;Harveson et al. 2004;Jackson et al. 2005;Haines et al. 2006;Martínez-Calderas et al. 2011;Torres-Romero et al. 2017;Galindo-Aguilar et al. 2019). Several studies indicate that the presence of the ocelot is adversely affected by local disturbances, such as land-use changes and forest fragmentation (Garmendia et al. 2013;Cruz et al. 2018;Wang et al. 2019;Lombardi et al. 2022). Habitat fragmentation can influence the home range of the ocelot (Cruz et al. 2019) by reducing the area of habitat fragments (Garmendia et al. 2013;Lombardi et al. 2020). ...
... For example, large-sized felines are more abundant in fragments with large core areas, making them susceptible to edge effects, where they conflict with livestock and humans (Luskin et al. 2017;Cruz et al. 2018). Lombardi et al. (2022) observed that ocelots avoid areas with edge habitats and are more prevalent in core areas of the fragment (Wang et al. 2019). Other felines with more flexible diets are more tolerant of edge habitats or even become more abundant in degraded habitats because they adapt to the changing prey availability near the edges (Prugh et al. 2009;Delibes-Mateos et al. 2014;Gil-Fernández et al. 20157;Cruz et al. 2018). ...
Ocelots are relatively tolerant to habitat modification. However, it has been observed that they may be sensitive to habitat loss and fragmentation as a result of human development. The Sierra Norte de Puebla is considered a potential habitat for ocelots and other tropical felines. However, it has suffered heavy loss and fragmentation of its natural ecosystems, which considerably affects habitat availability and quality. This study analyzed the land-use changes and habitat fragmentation in the distribution range of the ocelot in the Sierra Norte de Puebla, Mexico, from 1993 to 2020. Habitat suitability was determined using potential distribution models and vegetation and land-use maps from 1993, 2003, and 2020, obtained using supervised classification of Landsat images. The resulting maps were reclassified in terms of the habitat suitability for Leopardus pardalis according to their quality. Land-use changes and habitat loss were quantified with a transition matrix, and fragmentation was assessed using the Morphological Spatial Pattern Analysis tool of the program GUIDOS. These habitat fragments were quantified using the integral index of connectivity with the CONEFOR Sensinode program. We estimated that 22.2 % of the study area has suitable conditions for ocelots. From 1993 to 2020, the area covered by natural vegetation decreased 16 % at an annual rate of-2.4 %. During this period, the mean fragment size and shape index decreased; on the other hand, the number of fragments and the Euclidean distance between fragments increased. The percentages of edge, branch, and islet vegetation dropped from 1993 to 2003 but increased in 2020. The connectivity analysis indicated that two habitat fragments showed high values of the integral index of connectivity. The increase in anthropogenic cover and the habitat loss for L. pardalis between 1993 and 2020 affected mainly vegetation fragments considered optimal for the persistence of this species. In these ecosystems, agricultural and livestock practices are expanding vigorously, increasing edge habitats and decreasing the core area of habitat fragments. The areas that recorded the presence of ocelots have optimum conditions to serve as biological corridors in the Sierra Madre Oriental, particularly in the portion of the Sierra Norte de Puebla. The fragmentation of the ocelot habitat is of particular concern and should be addressed strategically for the long-term conservation of the ocelot and regional biodiversity.
Wildlife reintroduction site selection requires the consideration of not only a species' ecology but also socio‐political factors that may impact conservation efforts. These socio‐political dimensions may be especially important for endangered carnivore reintroductions on private lands in the United States, where landowner support for the reintroduction is a necessity given landowner concerns about ecological and legal impacts of carnivore restoration. We designed an assessment to identify potential sites for reintroduction of the federally endangered ocelot ( Leopardus pardalis pardalis ) in Texas, a state where over 97% of lands are privately owned. We incorporated International Union for Conservation of Nature recommendations into a geospatial analysis evaluating potential reintroduction sites based on site size, ecological and life history requirements of ocelots, potential natural and anthropogenic threats, and the socio‐political context of each site. We identified the five highest‐ranking sites that had species‐specific suitable landscape structure of woody cover, fine‐scale vegetative cover, minimal natural and anthropogenic threats, and that present land ownership patterns that are logistically feasible for conservation planners to navigate. Our assessment provided information for ocelot conservation planning and established a framework for incorporating private land data into large‐scale assessments of wildlife reintroduction sites on private lands.
Reliable estimates of population density and size are crucial to wildlife conservation, particularly in the context of the Endangered Species Act. In the United States, ocelots (Leopardus pardalis pardalis) were listed as endangered in 1982, and to date, only one population density estimate has been reported in Texas. In this study, we integrated vegetation metrics derived from LiDAR and spatial capture-recapture models to discern factors of ocelot encounter rates and estimated localized population estimates on private ranchlands in coastal southern Texas. From September 2020 to May 2021, we conducted a camera trap study across 42 camera stations on the East Foundation’s El Sauz Ranch, which was positioned within a larger region of highly suitable woody and herbaceous cover for ocelots. We observed a high density of ocelots (17.6 ocelots/100 km2) and a population size of 36.3 ocelots (95% CI: 26.1–58.6) with the 206.25 km2 state space area of habitat. The encounter probability of ocelots increased with greater canopy cover at 1-2 m height and decreasing proximity to woody cover. These results suggest that the incorporation of LiDAR-derived vegetative canopy metrics allowed us to understand where ocelots are likely to be detected, which may aid in current and future population monitoring efforts. These population estimates reflect the first spatially explicit and most recent estimates in a portion of the northernmost population of ocelots in southern Texas. This study further demonstrates the importance of private working lands for the recovery of ocelots in Texas.
Context
Road networks can negatively impact wildlife populations through habitat fragmentation, decreased landscape connectivity, and wildlife-vehicle collisions, thereby influencing the spatial ecology and population dynamics of imperiled species. The ocelot (Leopardus pardalis) is a federally endangered wild felid in South Texas, with a high mortality rate linked to vehicle collisions.
Objectives
Using a multi-scale approach, we quantified and examined landscape spatial structure at ocelot roadkill locations, and between roadkill locations of male and female ocelots.
Methods
We quantified the spatial distribution of land cover types at 26 ocelot–vehicle collision sites in South Texas that occurred from 1984–2017. We compared landscape metrics of woody, herbaceous, and bare ground cover types across multiple spatial scales at roadkill locations to those from random road locations, and between male and female ocelots.
Results
Roadkill sites consisted of 13–20% more woody cover than random locations. Woody patches at roadkill sites were 7.1–11% larger (2.4 ha) closer to roads and spaced 10–16 m closer together farther away from roads compared to random locations. Percent woody cover was the best indicator of ocelot–vehicle collision sites; there were no differences in woody cover between male and female road mortality locations.
Conclusion
These findings suggest that ocelots are likely struck by vehicles while crossing between habitat patches. Roads that bisect areas of woody cover have negative impacts on ocelots by increasing habitat fragmentation and vulnerability to vehicle collisions. Crossing structures should be placed in areas with ≥ 30% woody cover and 3.5 ha woody patches.
Estimates of population density are crucial for wild felid conservation and are commonly conducted using camera trapping. Spatially explicit capture-recapture (SCR) survey designs often use two cameras per station to photograph both flanks of a spotted felid to confirm identities. However, if the sampling grid is inadequate, and detector devices are unable to capture an animal’s complete movements, density may be overestimated. Density analyses incorporating identification inputs from both flanks derived from unpaired camera stations may offer a cost-effective solution by doubling the number of stations available to researchers. During 2008, we surveyed 164 sites for jaguars, ocelots, and bobcats using unpaired camera stations (mean trap nights per camera = 32.66, inter-trap distance = 800 m) on private ranching lands in Sonora, Mexico. We obtained 15, 52, and 229 detections of jaguars, ocelots, and bobcats from 9, 35, and 87 stations, respectively. SCR density estimates (individuals/100 km2) derived from a maximum likelihood multi-session model and a Bayesian spatial partial identity model (SPIM) were similar: 4.61 and 1.54 (jaguar), 4.66 and 4.33 (ocelot), and 15.22 and 15.88 (bobcat), respectively. Due to insufficient recaptures of jaguars, only SPIM provided a credible estimate of jaguar density. Jaguar density was one of the lowest reported across their distribution, which was expected given Sonora’s location at the periphery of the jaguar’s range. However, ocelot and bobcat populations appear to be healthy in Sonora, even within unprotected ranchlands. We recommend the use of SPIM to estimate the density of spotted felids with any dataset containing few recaptures in unpaired camera surveys.
About 80% of the known breeding population of ocelots (Leopardus pardalis) in the USA occurs exclusively on private ranches in northern Willacy and Kenedy counties in South Texas. These private ranches support several large contiguous undisturbed patches of thornscrub, which is preferred by ocelots. Past studies have indicated ocelots in South Texas select for woody patches that contain extremely dense thornscrub (i.e., 95% canopy cover and 85% vertical cover) and require large patches of woody cover to survive. Landscape metrics have been used to explain ocelot habitat use in fragmented areas, but their application in less-fragmented rangelands is lacking. From 2011 to 2018, we used camera traps on the East Foundation’s El Sauz Ranch to assess seasonal habitat use of ocelots relative to landscape structure, configuration, and complexity and other site-level factors in South Texas. Seasonal habitat use and detection were positively influenced by larger mean patch area and lower landscape shape index values. We also observed ocelots were less likely to be detected during periods of drought and exhibited a seasonal trend in detection. Ocelots used woody patches that were larger and more regularly shaped, indicating a preference for areas with a lower degree of fragmentation across the study area. As patches become larger, they will coalesce over time and form larger woody aggregates, which will promote ocelot habitat use. Brush management needs to be strategic as patch area and shape index are a limiting factor to promote ocelot habitat use on working rangelands in South Texas. These results demonstrate the ability to use landscape metrics to discern the effects of spatial structure of vegetation communities relative to ocelot occupancy parameters.
The Rio Grande Delta and surrounding rangelands in Texas has become one of the fastest urbanizing regions in the United States over the last 35 years. We assessed how land cover trends contributed to the large-scale processes that have driven land cover change since 1987. We classified LANDSAT imagery from 1987 to 2016 to quantify different rates of land cover change and used housing density scenarios to project changes in the amount and spatial distribution of woody cover until 2050 and its potential impact on wild felid habitat. Since 1987, woody cover increased from 3.9% along with patch and edge density, whereas mean patch area and Euclidean nearest neighbor decreased. Closer inspection revealed that woody encroachment of small patches (<1 ha) was the leading cause of woody cover increase by a magnitude of 4, with an observed significant skewness and kurtosis in the frequency distribution of patch size across years. By 2050, urbanization will be the dominant landscape type and at least 200 km2 of woody cover may be lost, thereby affecting felid populations in South Texas. These results provide important information for predicting future woody cover fragmentation and its potential impact on the connectivity of wild felid populations.
Protected areas (PAs), priority terrestrial regions (PTRs) and priority terrestrial sites (PTSs) are strategies for conserving natural resources. However, loss of coverage on the peripheries can lead to isolation between these conservation areas. The present study analyzed the association of the change of coverage inside and outside 2 PAs, 5 PTRs and 128 PTSs in Tamaulipas with the richness and geographic distribution of 5 species groups (strict, semiaquatic and tolerant hydrophiles, as well as gastropods and pteridophytes in 3 periods (1986, 2002 and 2011). In addition, we identified areas with similar species composition and socioeconomic-environmental factors related to the change in coverage. The highest richness and geographic distribution of aquatic plants occurred outside the conservation areas, while the greatest richness of ferns and gastropods was present inside them. The greatest loss of coverage occurred outside the El Cielo Biosphere Reserve and the Sierra de Tamaulipas PA. The loss of native cover increased in the last 30 years and is greater outside the conservation areas, therefore is necessary to propose and implement strategies to reduce the isolation of these areas.
Knowing the potential distribution of species helps to focus conservation efforts more effectively, mainly when dealing with endangered species. The aim of this study was to generate potential distribution models for four species of small wild felids in Mexico (Leopardus pardalis, Leopardus wiedii, Lynx rufus and Puma yagouaroundi). The models were generated based on felids presence records, and topographic, anthropic and vegetation drivers. We used 473 records (171 for L. pardalis, 140 for L. wiedii, 86 for L. rufus and 76 for P. yagouaroundi) to build eleven models per species to then select the three with the best performance and included them in ensemble models. These were based on the formula of the weighted average, which considers the performance of the algorithms evaluated with a subsample of testing records, from which the area under the curve is calculated. In this way, in the ensemble model the consistent zones between algorithms are included, but the one with the best performance predominates. The species with the largest potential distribution area was L. pardalis with 34.3% of the national territory, while L. rufus had the smallest area (14.3%). In the four species a unique set of variables was identified that influence the probability of presence, however the altitude, the arid vegetation and the population density were important variables for three of the four species. We verified our models with recently published presence records. The results of this study reflect a robust analysis of the current and potential distribution of four species of wild felids in Mexico. In addition to being the first step to develop effective conservation strategies at national and local levels.
Quantifying landscape characteristics and linking them to ecological processes is one of the central goals of landscape ecology. Landscape metrics are a widely used tool for the analysis of patch‐based, discrete land‐cover classes. Existing software to calculate landscape metrics has several constraints, such as being limited to a single platform, not being open‐source, or involving a complicated integration into large workflows. We present landscapemetrics, an open‐source R package that overcomes many constraints of existing landscape metric software. The package includes an extensive collection of commonly used landscape metrics in a tidy workflow. To facilitate the integration into large workflows, landscapemetrics is based on a well‐established spatial framework in R. This allows pre‐processing of land‐cover maps or further statistical analysis without importing and exporting the data from and to different software environments. Additionally, the package provides many utility functions to visualize, extract, and sample landscape metrics. Lastly, we provide building‐blocks to motivate the development and integration of new metrics in the future. We demonstrate the usage and advantages of landscapemetrics by analysing the influence of different sampling schemes on the estimation of landscape metrics. In so doing, we demonstrate the many advantages of the package, especially its easy integration into large workflows. These new developments should help with the integration of landscape analysis in ecological research, given that ecologists are increasingly using R for the statistical analysis, modelling, and visualization of spatial data. This article is protected by copyright. All rights reserved.
Amazonia forest plays a major role in providing ecosystem services for human and sanctuaries for wildlife. However, ongoing deforestation and habitat fragmentation in the Brazilian Amazon has threatened both. The ocelot is an ecologically important mesopredator and a potential conservation ambassador species, yet there are no previous studies on its habitat preference and spatial patterns in this biome. From 2010 to 2017, twelve sites were surveyed, totaling 899 camera trap stations, the largest known dataset for this species. Using occupancy modeling incorporating spatial autocorrelation, we assessed habitat use for ocelot populations across the Brazilian Amazon. Our results revealed a positive sigmoidal correlation between remote‐sensing derived metrics of forest cover, disjunct core area density, elevation, distance to roads, distance to settlements and habitat use, and that habitat use by ocelots was negatively associated with slope and distance to river/lake. These findings shed light on the regional scale habitat use of ocelots and indicate important species–habitat relationships, thus providing valuable information for conservation management and land‐use planning. Using occupancy modeling incorporating spatial autocorrelation, we assessed habitat use for ocelot populations across the Brazilian Amazon. Our results revealed a positive sigmoidal correlation between remote‐sensing derived metrics of forest cover, elevation, distance to roads, distance to settlements, and habitat use, and that habitat use by ocelots was negatively associated with slope and distance to river. These findings shed light on the regional scale habitat use of ocelots and indicate important species–habitat relationships, thus providing valuable information for conservation management and land‐use planning. Please visit https://youtu.be/RunyPlYxun8
Variation in activity patterns and habitat use are subject to both environmental factors and interactions with other species. We evaluated the ecological factors that affect habitat use by Leopardus pardalis as well as the effects of the presence of potential prey, Dasyprocta punctata. From an arrangement of 70 camera traps, installed between March 2015 and February 2016, we estimate the detection probability and habitat use for both species with a single season model. The selected models suggest that L. pardalis habitat use (70.4%, IC: 63.2–77.6) varies negatively with forest edge density around 1000 m radius, but no effects resulting from D. punctata presence are reported. Our results suggest the absence of spatial exclusion between both species in the study area and a coexistence facilitated by marked temporal segregation.
In this paper, the ecological integrity hierarchy framework (EIHF) and the natural capital index framework (NCI) are integrated as decision-making tools for evaluating the natural capital of Mexico. Two hierarchy-levels of ecological integrity indicators are used to estimate the quality and quantity of the natural capital, the amount of ecological degradation and ecological sustainability. After human transformation, the extent still considered as “natural” in the country is ∼67%; while the amount of human transformed areas is ∼33%, which gives a total estimate of NCI=0.334; i.e., only ∼33.4% of the national capital remains available, while ∼33% is ecologically degraded. Furthermore, the critical natural capital; i.e., the legacy for future generations that remains in the country is only ∼12%. The total estimated value of the current natural capital in Mexico is ∼$457.1 billion/yr, which is ∼435 times greater than the national GDP ($1.051 billion in 2010). The cost of maintaining the degradation of the natural capital is ∼$144.6 million/yr (∼138 times greater than national GDP in 2010). The potential value of the natural capital after restoration would be ∼$602 billion/yr. Valuing the natural capital can be helpful for strategic environmental evaluations and useful for spatial decision support systems that evaluate natural capital as a decision-making tool.
Ocelots (Leopardus pardalis) are listed as least concern on the International Union for Conservation of Nature (IUCN) Red list of Threatened Species, yet we lack knowledge on basic demographic parameters across much of the ocelot's geographic range, including population density. We used camera-trapping methodology and spatially explicit capture-recapture (SECR) models with sex-specific detection function parameters to estimate ocelot densities across 7 field sites over 1 to 12 years (from data collected during 2002–2015) in Belize, Central America. Ocelot densities in the broadleaf rainforest sites ranged between 7.2 and 22.7 ocelots/100 km², whereas density in the pine (Pinus spp.) forest site was 0.9 ocelots/100 km². Applying an inverse-variance weighted average over all years for each broadleaf site increased precision and resulted in average density ranging from 8.5 to 13.0 ocelots/100 km². Males often had larger movement parameter estimates and higher detection probabilities at their activity centers than females. In most years, the sex ratio was not significantly different from 50:50, but the pooled sex ratio estimated using an inverse weighted average over all years indicated a female bias in 1 site, and a male bias in another. We did not detect any population trends as density estimates remained relatively constant over time; however, the power to detect such trends was generally low. Our SECR density estimates were lower but more precise than previous estimates and indicated population stability for ocelots in Belize. © 2018 The Authors. Journal of Wildlife Management Published by Wiley Periodicals, Inc. on behalf of The Wildlife Society. © 2018 The Authors. Journal of Wildlife Management Published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.
Temporal segregation may be one of the most effective mechanism adopted by a subordinate species to reduce competition with a dominant species. We hypothesized temporal segregation by ocelots as the main strategy of reducing direct contact with pumas and humans in Atlantic Forest protected areas. Through a standardized camera trap protocol, we measured the degree of activity overlap between ocelots and pumas and between ocelots and humans using circular statistics. Additionally, we investigated predictor variables that may influence the temporal activity of ocelots. Ocelots and pumas showed nocturnal and cathemeral activity, respectively, whereas humans were diurnal. Although the coefficient of overlap between the activity of ocelots and pumas was high (Δ^ 1 = 0.74), the Mardia-Watson-Wheeler test showed significant dissimilarities between their daily distributions of records (W = 5.86; d.f. = 2; P = 0.05). The coefficient of overlap between the activity of ocelots and humans was low (Δ^ 4 = 0.32) as also revealed by the Mardia-Watson-Wheeler test (W = 179.51; d.f. = 2; P < 0.001). Ocelots enhanced their nocturnal activity in sites where occupancy probability of pumas was high and either in sites with more pasture or near human settlements. Our finding suggests that temporal segregation may be one mechanism adopted by ocelots to allow its coexistence with pumas and humans in Atlantic Forest remnants. However, it is unknown whether temporal segregation per se will be enough to guarantee long-term persistence of ocelots in the current degraded scenario of the Atlantic Forest.
Abstract Introduction Deforestation significantly impacts large carnivores that depend on large tracts of interconnected forest habitat and that are sensitive to human activities. Understanding the relationship between habitat use and spatial distribution of such species across human modified landscapes is critical when planning effective conservation strategies. This study assessed the presence of potential landscape connectivity thresholds resulting from habitat fragmentation associated with different deforestation patterns using a scale-based approach that links species-specific home ranges with the extent of anthropogenic activities. The objectives were (1) to quantify the spatial and temporal distribution of natural vegetation for five common deforestation patterns and (2) to evaluate the connectivity associated with these patterns and the existence of potential thresholds affecting jaguar dispersal. The Bolivian lowlands, located within jaguar conservation units, were analysed with landscape metrics to capture the spatial and temporal changes within deforested areas and to determine potential impact on jaguar connectivity and connectivity thresholds for dispersal. Results Over the period of 1976–2005, the amount of natural vegetation has decreased by more than 40% in all locations with the biggest changes occurring between 1991 and 2000. Landscape spatial structure around jaguar locations showed that jaguars used areas with mean proportion of natural areas = 83.14% (SE = 3.72%), mean patch density = 1.16 patches/100 ha (SE = 0.28 patches/100 ha), mean patch area = 616.95 ha (SE = 172.89 ha) and mean edge density = 705.27 m/ha (SE = 182.19 m/ha).We observed strong fragmentation processes in all study locations, which has resulted in the connectivity of jaguar habitat decreasing to
Ocelots (Leopardus pardalis) are legally protected in Mexico as an endangered species. The main threats throughout the species’ range are habitat loss and fragmentation. The ocelot population that inhabits Sonora, Mexico, is at the northern limit of the species’ distribution and knowledge about it is still scarce. We used remote camera data from 2010-2012 and SECR models for density estimation and the Barker Robust Design mark-recapture model to estimate the survival, abundance, and density of ocelots in a arid region in northeastern Sonora, Mexico. Average apparent survival was 0.65 for females and 0.63 for males; abundance estimates ranged from 2.02 ± 0.13 to 7.06 ± 0.24 ocelots. Average density was 0.63 ± 0.06 females 100 km⁻² and 0.95 ± 0.08 males 100 km⁻² using the Barker Robust Design and 0.51 ± 0.26 females 100 km⁻² and 0.77 ± 0.25 males 100 km⁻² using the SECR. Our survival and density estimates are the lowest reported. However, due to the low human population density in our study area, we consider that our findings must be associated with natural processes rather than human-caused disturbance, without dismissing an additive factor by the latter. Arid environmental features could have a negative influence over primary productivity and consequently on prey availability, limiting ocelot survival and density in this region. Large tracts of unpopulated wildlands over a non-fragmented landscape favor ocelots in this area, and it is important to maintain current habitat conditions for this Neotropical species to continue thriving in this region of North America.
The ocelot is the third largest cat that occurs in Mexico. Despite all the information that has been collected regarding its distribution in the country, little is known about its basic ecology in Mexico. In this study we estimated population density of ocelots and their activity patterns for the Greater Lacandona Ecosystem region. Data were obtained through camera traps. We used 33 camera trap stations that were active during 60 consecutive days. The effective sampling effort was 1,920 trap days. Population density was estimated through Bayesian Spatial Explicit Capture-Recapture Models. In addition, the activity pattern of ocelots was determined by the time recorded of all photographs obtained. We estimated a minimal density of 12.9 ± 5.39 ocelots for each 100 km² for the southern Montes Azules Biosphere Reserve. According with the photographic records we identified that ocelots were active both day and night. Our results are similar to those obtained in other areas located in the tropical rain forests of Central America with the classic capture-recapture methods. In addition, this study shows the potential of this preserved area for maintaining long-term population of ocelots in the tropical rain forest of the Greater Lacandona Ecosystem. More information about this species needs to be obtained, especially for regions characterized by habitat fragmentation and human perturbation.
Ocelots (Leopardus pardalis) are presumed to be the most abundant of the wild cats throughout their distribution range and to play an important role in the dynamics of sympatric small-felid populations. However, ocelot ecological information is limited, particularly for the Amazon. We conducted three camera-trap surveys during three consecutive dry seasons to estimate ocelot density in Amanã Reserve, Central Amazonia, Brazil. We implemented a spatial capture-recapture (SCR) model that shared detection parameters among surveys. A total effort of 7020 camera-trap days resulted in 93 independent ocelot records. The esti- mate of ocelot density in Amanã Reserve (24.84 ± SE 6.27 ocelots per 100 km2) was lower than at other sites in the Amazon and also lower than that expected from a correlation of density with latitude and rainfall. We also discuss the importance of using common parame- ters for survey scenarios with low recapture rates. This is the first density estimate for oce- lots in the Brazilian Amazon, which is an important stronghold for the species.
The presence of ocelot in the “Cerro de la Silla” federal natural protected area is documented and confirmed, this is just the second formal record of the species for the State of Nuevo León, Mexico.
INTRODUCTION:
The ocelot (Leopardus pardalis) is a Neotropical cat which is threatened by illegal hunt and habitat destruction in the Mexican territory. Mexican and American authorities are interested in promoting their conservation. The MaxEnt algorithm allows modeling the potential distribution of elusive species, for instance, the ocelot. This has been based on trustable presence records and some other information about the habitat condition. This work was developed with the aim of generating important information about the species in Northeastern Mexico, especially, with the purpose of determining its potential distribution.
METHODS:
Our study was conducted in six physiographic subprovinces in the Mexican states of Tamaulipas and San Luis Potosí. Sixty-trhee recent records about the ocelot were obtained, 41 through literature and 22 from field surveys , between May 2006 to May 2009. In order to develop a prediction model which let us know the animal potential distribution, twenty-seven bioclimatic, topographic, vegetation and anthropic variables were used through the MaxEnt software.
RESULTS:
The model AUC was of 0.8221 ± 0.009. The most related variables about the ocelot presence were: precipitation of wettest month and quarter, vegetation cover, vegetation type, terrain elevation, precipitation of coldest quarter, terrain slope, human population density, and distance to roads. The potential distribution area overs 20.8 % of the study area. The physiographic subprovinces showing the highest potential distribution were: llanuras y lomerios (7.4 %), Carso Huasteco (4.8 %), Gran Sierra Plegada (4.5 %), and sierras and llanuras occidentales (3.4 %). The llanura costera Tamaulipeca subprovince showed lower potential distribution; meanwhile, llanuras de Coahuila y Nuevo Leon and sierras y llanuras del norte de Guanajuato were not suitable distribution for ocelot.
DISCUSSIONS AND CONCLUSIONS:
In order to obtain the ocelot potential distribution model we use recent information collected through field work and surveys. Through this, we could achieve a robust model, where were relevant both bioclimatic and landscape variables. There are patches of habitat important in size and quality for ocelot. The physiographic subprovinces with the roughest landscape were the ones where the highest presence of the species. This study complements the ocelot distributional range in Northeastern Mexico and providing important information about the habitat quality in that portion of the country, as well as the difficulty to possible connectivity between Mexico and USA.
Urbanization is a primary driver of landscape conversion with far-reaching effects on landscape pattern and process, particularly related to the population characteristics of animals. Urbanization can alter animal movement and habitat quality, both of which can influence population abundance and persistence. We evaluated three important population characteristics (population density, site occupancy, and species detection probability) of a medium-sized and a large carnivore across varying levels of urbanization. Specifically, we studied bobcat and puma populations across wildland, exurban development, and wildland-urban interface (WUI) sampling grids to test hypotheses evaluating how urbanization affects wild felid populations and their prey. Exurban development appeared to have a greater impact on felid populations compared to habitat adjacent to a major urban area (i.e., WUI); estimates of population density for both bobcats and pumas were lower in areas of exurban development compared to wildland areas, whereas population density was similar between WUI and wildland habitat. Bobcats and pumas were less likely to be detected in habitat as the amount of human disturbance associated with residential development increased at a site, which was potentially related to reduced habitat quality resulting from urbanization. However, occupancy of both felids was similar between grids in both study areas, indicating that this population metric was less sensitive than density. At the scale of the sampling grid, detection probability for bobcats in urbanized habitat was greater compared to wildland areas, potentially due to restrictive movement corridors and funneling of animal movements in landscapes influenced by urbanization. Occupancy of important felid prey (cottontail rabbits and mule deer) was similar across levels of urbanization, although elk occupancy was lower in urbanized areas. Our study indicates that the conservation of medium- and large-sized felids associated with urbanization will likely be most successful if large areas of wildland habitat are maintained, even in close proximity to urban areas, and wildland habitat is not converted to low-density residential development.
The ocelot Leopardus pardalis is of particular significance in terrestrial communities due to its ecological role within the group of small-sized felids and as a mesopredator. However, despite the reduction of ocelot habitat in Southeast Mexico, there are still very few ecological studies. This research aimed to contribute with some ecological aspects of the species in this region. For this, 29 camera trap stations were established in a rain forest in Los Chimalapas (an area of 22 km2) during a two years period (March 2011-June, 2013), in Oaxaca state, Southeast Mexico. Data allowed the estimation of the population density, activity pattern, sex ratio, residence time, and spatial distribution. Population density was calculated using Capture-Recapture Models for demographically open populations; besides, circular techniques were used to determine if nocturnal and diurnal activity varied significantly over the seasons, and Multiple Discriminant Analysis was used to determine which of the selected environmental variables best explained ocelot abundance in the region. A total of 103 ocelot records were obtained, with a total sampling effort of 8,529 trap-days. Density of 22-38 individuals/100 km2 was estimated. Ocelot population had a high proportion of transient individuals in the zone (55%), and the sex ratio was statistically equal to 1:1. Ocelot activity was more frequent at night (1:00-6:00h), but it also exhibited diurnal activity throughout the study period. Ocelot spatial distribution was positively affected by the proximity to the village as well as by the amount of prey. The ocelot population here appears to be stable, with a density similar to other regions in Central and South America, which could be attributed to the diversity of prey species and a low degree of disturbance in Los Chimalapas.
There is little information on the population status of the ocelot
Leopardus pardalis
in Mexico. In the Sierra Abra-Tanchipa Biosphere Reserve, in San Luis Potosí, ocelots are affected by habitat loss and fragmentation as a result of increased agricultural development. We used photographic identification in camera-trapping capture–recapture surveys to determine population abundance and density during the dry season and subsequent early and late humid seasons during April 2011–March 2012. We recorded 80 photographs of 15 individuals (10 males, one female, and four of undetermined sex) in 7,786 camera-days. Abundance was estimated using a closed capture heterogeneity model, yielding an estimated population of 9 ± SE 3 in the dry season and 21 ± SE 8 and 15 ± SE 5 during the subsequent early and late humid seasons, respectively. Spatially explicit density estimates were 0.04 and 0.03–0.18 individuals per km
2
for the dry and humid seasons, respectively, and were similar (P > 0.612) among seasons. Peaks in ocelot activity occurred during 20.00–04.00. We conclude that the ocelots of the Sierra Abra-Tanchipa Reserve have a low population density and may face geographical and biological isolation as a result of habitat conversion. Continued monitoring and improved understanding of the movements and habitat preferences of ocelots are necessary to ensure their continued persistence, and connectivity between this population and others in north-east Mexico.
We present HotSpotter, a fast, accurate algorithm for identifying individual animals against a labeled database. It is not species specific and has been applied to Grevy's and plains zebras, giraffes, leopards, and lionfish. We describe two approaches, both based on extracting and matching keypoints or “hotspots”. The first tests each new query image sequentially against each database image, generating a score for each database image in isolation, and ranking the results. The second, building on recent techniques for instance recognition, matches the query image against the database using a fast nearest neighbor search. It uses a competitive scoring mechanism derived from the Local Naive Bayes Nearest Neighbor algorithm recently proposed for category recognition. We demonstrate results on databases of more than 1000 images, producing more accurate matches than published methods and matching each query image in just a few seconds.
Land-cover change is the result of complex multi-scale interactions between socioeconomic, demographic, and environmental factors. Demographic change, in particular, is thought to be a major driver of forest change. Most studies have evaluated these interactions at the regional or the national level, but few studies have evaluated these dynamics across multiple spatial scales within a country. In this study, we evaluated the effect of demographic, environmental, and socioeconomic variables on land-cover change between 2001 and 2010 for all Mexican municipalities (n = 2,443) as well as by biome (n = 4). We used a land-cover classification based on 250-m MODIS data to examine the change in cover classes (i.e., woody, mixed woody, and agriculture/herbaceous vegetation). We evaluated the trends of land-cover change and identified the major factors correlated with woody vegetation change in Mexico. At the national scale, the variation in woody vegetation was best explained by environmental variables, particularly precipitation; municipalities where woody cover increased tended to be in areas with low average annual precipitation (i.e., desert and dry forest biomes). Demographic variables did not contribute much to the model at the national scale. Elevation, temperature, and population density explained the change in woody cover when municipalities were grouped by biome (i.e., moist forest, dry forest, coniferous forest, and deserts). Land-cover change at the biome level showed two main trends: (1) the tropical moist biome lost woody vegetation to agriculture and herbaceous vegetation, and (2) the desert biome increased in woody vegetation within more open-canopy shrublands.
Owing to habitat conversion and conflict with humans, many carnivores are of conservation concern. Because of their elusive nature, camera trapping is a standard tool for studying carnivores. In many vertebrates, sex-specific differences in movements – and therefore detection by cameras – are likely. We used camera trapping data and spatially explicit sex-specific capture–recapture models to estimate jaguar density in Emas National Park in the central Brazilian Cerrado grassland, an ecological hotspot of international importance. Our spatially explicit model considered differences in movements and trap encounter rate between genders and the location of camera traps (on/off road). We compared results with estimates from a sex-specific non-spatial capture–recapture model. The spatial model estimated a density of 0.29 jaguars 100km−2 and showed that males moved larger distances and had higher trap encounter rates than females. Encounter rates with off-road traps were one tenth of those for on-road traps. In the non-spatial model, males had a higher capture probability than females; density was estimated at 0.62 individuals 100km−2. The non-spatial model likely overestimated density because it did not adequately account for animal movements. The spatial model probably underestimated density because it assumed a uniform distribution of jaguars within and outside the reserve. Overall, the spatial model is preferable because it explicitly considers animal movements and allows incorporating site-specific and individual covariates. With both methods, jaguar density was lower than reported from most other study sites. For rare species such as grassland jaguars, spatially explicit capture–recapture models present an important advance for informed conservation planning.
The ocelotLeopardus pardalis Linnaeus, 1758 is an endangered felid in the United States currently restricted to southern Texas. The objectives of our
study were to obtain data on ocelot parturition dates, fecundity, sex ratios, den characteristics, and first year survival,
all of which are critical in development of population viability models. Sixteen parturition events were recorded ranging
from mid-April to late December for 12 wild ocelots. Cumulatively, litters consisted of 1 or 2 kittens (¯ = 1.2 ± 0.44 SD).
Cumulative sex ratio was 1∶2.5 (male:female); however, there was no significant difference between the observed sex ratio
and a 1∶1 sex ratio. Ten den sites were in close proximity (≤ 10 m) to dense thornshrub. Adult female ocelots used 2 to 4
den sites for each litter with distance between consecutively occupied dens ranging from 110 to 280 m (¯ = 158 m ± 93 SD).
An estimated annual survival for ocelots 0 to 1 year of age was 0.68. Evidence suggests that ocelots in the wild may breed
more frequently than had been previously hypothesized.
Recently developed capture-mark-recapture methods allow us to account for capture heterogeneity among individuals in the form of discrete mixtures and continuous individual random effects. In this article, we used simulations and two case studies to evaluate the effectiveness of continuously distributed individual random effects at removing potential bias due to capture heterogeneity, and to evaluate in what situation the added complexity of these models is justified. Simulations and case studies showed that ignoring individual capture heterogeneity generally led to a small negative bias in survival estimates and that individual random effects effectively removed this bias. As expected, accounting for capture heterogeneity also led to slightly less precise survival estimates. Our case studies also showed that accounting for capture heterogeneity increased in importance towards the end of study. Though ignoring capture heterogeneity led to a small bias in survival estimates, such bias may greatly impact management decisions. We advocate reducing potential heterogeneity at the sampling design stage. Where this is insufficient, we recommend modelling individual capture heterogeneity in situations such as when a large proportion of the individuals has a low detection probability (e.g. in the presence of floaters) and situations where the most recent survival estimates are of great interest (e.g. in applied conservation).
Few studies have been conducted on the food habits of the ocelot (Leopardus pardalis), considered an endangered feline in Mexico. Past studies showed that rodents were the main component of ocelot diet. In our study ocelot prey consumption was measured as frequency of occurrence of prey in scats and then converted to biomass. The spiny-tailed iguana (Ctenosaura pectinata) was the most important prey of ocelots, followed by the spiny pocket mouse (Liomys pictus). Other rodents and some birds were also present in the scats, although representing only a minor proportion of the ocelot's diet. Evidence of subadult white-tailed deer (Odocoileus virginianus) was also found in scats indicating that ocelots can either capture prey bigger than themselves or are using deer as carrion.
There are three species of Neotropical cats whose northernmost distribution reaches the USA-Mexico border region: the jaguar Panthera onca, ocelot Leopardus pardalis and jaguarundi Herpailurus yagouaroundi. To ensure the long-term viability of Neotropical cat populations in this region it is imperative to identify current distribution and status in the northern limits of their range to conserve important populations effectively. The purpose of this study was to construct a blueprint of priority conservation areas for each species in the border region. This was done by (1) compiling reliable sightings for each species from the early 1900s to 2003, (2) conducting field surveys to ascertain species presence, and (3) conducting a geographical information system based habitat mapping workshop in which 29 scientists and conservationists provided information on the distribution and status of each species. Participants were asked to delineate and describe specific areas in the border region where historical and recent sightings of Neotropical cats have occurred, resulting in a compilation of 864 felid sightings of which 283 where reliable and had physical evidence. Twenty-one Cat Conservation Units and seven Cat Conservation Corridors were identified as areas in which to concentrate efforts for protecting felids. Only 8.9% of these Corridors and 1.1% of the Units currently have any protection. An additional 12 Corridors and 12 Units were identified as areas requiring further study.
The distribution of ocelots Leopardus
pardalis in the USA is limited to southern Texas. Identification and monitoring of ocelot populations enables biologists to assess population health and status. Use of camera traps has been successfully used to monitor numerous populations of wild felids, including the ocelot. Our objectives were to identify ocelot presence within southern Texas and estimate ocelot population size and density. We used camera traps to survey for ocelots on four study sites in southern Texas. We recorded ocelot presence on one study site with an abundance estimate of three individuals and a density estimate of 0.30±SE 0.03 ocelots km−2. The conservation implications of this study suggest concentrating conservation efforts in and around the study site (Yturria Ranch) found to have ocelots. In addition, this study emphasizes the importance of including private landowners in the ocelot recovery process.
From July 1998 to July 2000 we collected locality information and habitat associations for 36 records of the Endangered ocelot Leopardus
pardalis in the Mexican State of Sonora. Twenty-seven (75%) of the records for which we could determine the biotic community association were associated with tropical and subtropical habitats, namely subtropical thornscrub, tropical deciduous forest or tropical thornscrub. Only males (11.1% of the total records) have been recorded in temperate oak and pine-oak woodland, and we conclude that the few ocelots reported from these habitats in the US State of Arizona were probably dispersing individuals. Three models of ocelot distribution in Sonora, based on vegetation types, the GARP modelling system and the Adaptive Kernel home range estimator, all produced similar results, with the ocelot mostly associated with the mountainous Sierra region of eastern Sonora. Large tracts of land with a low human population density make Sonora a stronghold for the northernmost distribution of ocelots.
We used remote cameras to obtain informa-tion on an elusive species and to examine the effects of different camera trapping methodologies on abun-dance estimates. We determined activity pattern, trail use, trap success, and density of ocelot Leopardus pardalis in seven cam-trap surveys across two habitat types in western Belize: tropical broad-leaf rainforest and tropical pine forest. Ocelots in the rainforest were active mostly at night, in particular immediately after sunset, and they travelled on low-use roads (especially in the wet season) and high-use roads (especially in the dry season) more than established and newly cut trails. Trap success was relatively high in the rainforest (2.11–6.20 captures per 100 trap nights) and low in the pine forest (0.13–0.15 captures per 100 trap nights). Camera trapping combined with mark-recapture sta-tistics gave densities of 25.82–25.88 per 100 km 2 in the broad-leaf versus 2.31–3.80 per 100 km 2 in the pine forest. Density estimates increased when animals re-peatedly captured at the same camera (zero-distance moved animals) were included in the buffer size analysis. Density estimates were significantly negatively cor-related with distance between cameras. We provide information on ocelot population status from an un-studied portion of its range and advise that camera trap methodologies be standardized to permit comparisons across sites.
Camera‐trapping is widespread in wildlife studies, especially for species with individually unique markings to which capture–recapture analytical techniques can be applied. The large volume of data such studies produce have encouraged researchers to increasingly look to computer‐assisted pattern‐recognition software to expedite individual identifications, but little work has been done to formally assess such software for camera‐trap data. We used 2 sets of camera‐trap images—359 images of jaguars ( Panthera onca ) and 332 images of ocelots ( Leopardus pardalis ) collected from camera traps deployed in 4 study sites in Orange Walk District, Belize, in 2015 and 2016—to compare the accuracy of 2 such programs, HotSpotter and Wild‐ID, and assess the effect of image quality on matching success. Overall, HotSpotter selected a correct match as its top rank 71–82% of the time, whereas the rate for Wild‐ID was 58–73%. Positive matching rates for both programs were highest for high‐quality images (85–99%) and lowest for low‐quality images (28–52%). False match rates were very low for HotSpotter (0–2%) but these were greater in Wild‐ID (6–28%). When lower ranks were also considered, both programs performed similarly (overall 22–24% nonmatches for HotSpotter, 17–26% nonmatches for Wild‐ID). We found that in both programs, images more often matched to other images of the same quality; therefore, including multiple reference images of an individual, of different qualities, improves matching success. These programs do not provide fully automatic identification of individuals and human involvement is still required to confirm matches, but we found that they are effective tools to expedite processing of camera‐trap data. We also offer usage recommendations for researchers to maximize the benefits of these tools. © 2020 The Wildlife Society.
Conversion of land cover is one of the main causes of global environmental change and identifying the regions where sustained trends of land change are occurring provides useful information for land and resources management. For all ecoregions in Mexico, we analyzed land use changes over 14 years (2001–2014) using MODIS images (250 m) and identified regions that had significant gains or loss of woody vegetation, pasturelands, or croplands. The land use patterns varied greatly among the 40 major ecoregions, but in general, woody vegetation and cropland cover increased while pastures decreased. In contrast to previous studies, much of the increase in croplands did not correspond with hotspots of decline in pastures but occurred in the Sonora and Chihuahuan deserts ecoregions in northern Mexico. Industrial cotton, sorghum, and pecans production for export where the major crops responsible for the increase in these ecoregions. Similar to patterns in the rest of Latin America, pasture expansion mainly occurred in ecoregions in the tropical moist forest biome (e.g. Veracruz and Peten-Veracruz ecoregions). The ecoregions that experienced the greatest increase in woody vegetation were the Balsas dry forest ecoregion along the Pacific coast and Trans Mexican volcanic oak-pine ecoregion. In both regions, rural-urban migration appears to be an important driver of the transition from grasslands to woody vegetation, while the conversion of croplands to woody vegetation in the Tamaulipan mezquital ecoregion was clearly associated with drug related violence. This study documents how the complex interactions among national and international demand for agricultural products, national policies, demography, violence and climate change are affecting land change across Mexico.
Occupancy Estimation and Modeling: Inferring Patterns and Dynamics of Species Occurrence, Second Edition, provides a synthesis of model-based approaches for analyzing presence-absence data, allowing for imperfect detection. Beginning from the relatively simple case of estimating the proportion of area or sampling units occupied at the time of surveying, the authors describe a wide variety of extensions that have been developed since the early 2000s. This provides an improved insight about species and community ecology, including, detection heterogeneity; correlated detections; spatial autocorrelation; multiple states or classes of occupancy; changes in occupancy over time; species co-occurrence; community-level modeling, and more. Occupancy Estimation and Modeling: Inferring Patterns and Dynamics of Species Occurrence, Second Edition has been greatly expanded and detail is provided regarding the estimation methods and examples of their application are given. Important study design recommendations are also covered to give a well rounded view of modeling.
Worldwide, private lands have attracted increased attention from conservationists, not only because most of the globe is privately owned, but also because private lands can be an asset to the protected area conservation strategy. In Brazil, the riverine Areas of Permanent Protection (APPs) are a key instrument of the Forest Code to protect biodiversity on private lands, acting as wildlife corridors. We assessed this putative role of APPs by evaluating how ocelot (Leopardus pardalis) occurrence is influenced by covariates in 3 cerrado landscapes dominated by sugarcane and managed forests of eucalyptus and pine trees. We collected detection–nondetection data by camera trapping during 2 dry seasons (2013 and 2014) at 208 stations (6,606 camera-days). We estimated ocelot detection and mean relative abundance using a single-species, single-season occupancy model that accounts for heterogeneous detection probability induced by variation in abundance. Modeling results showed that percentage of native forest was the most important covariate to explain mean relative abundance of ocelots. This parameter was also affected positively by APPs, with ocelots being more abundant inside than outside APPs and, unexpectedly, by sugarcane. Given our study design, however, the positive effect of this crop likely reflects the contact zone between sugarcane and native forest. Our findings show that landscape composition affects ocelot abundance and highlight the importance of APPs and Legal Reserves in agricultural landscapes. We conclude that, in such landscapes, compliance to the Forest Code by private land owners is key to supporting ocelot occurrence.
Ecological indicators that evaluate the status and trends of mammalian apex predators are necessary for monitoring the ecological integrity of landscapes. Several nation-wide spatial indicators that describe the status of apex predators after habitat transformation have been developed for México. These spatial indicators show the condition of the remnant natural landscape for maintaining the complexity of predator-prey interactions and habitat selection and use. The indicators were obtained using the concept of ecological integrity, that characterize the landscape based upon manifest and latent variables of naturalness, stability and self-organization, according with the measures of spatial distribution of species and natural habitat. When the current status is evaluated for individual species of apex predators, all species showed less than 50% of their distribution areas with a high degree of ecological integrity. Neotropical predators (such as jaguars and ocelots) are more threatened by the transformation of natural habitat, than their counterparts in Nearctic regions (e.g., bears, cougars, bobcats, and coyotes), which showed nonetheless, a high amount of their distribution areas with a high proportion of degraded habitat. The indicators allowed evaluating the status of still extant top predators in the landscape and their habitat condition within major ecoregions in the country.
The abundance of low-density species like carnivores is logistically difficult to directly estimate at a meaningful scale. Predictive distribution models are often used as a surrogate for density estimation. But because density can continue to increase as occupancy asymptotes at 1, occupancy may have little value as an index, and home range expansion in marginal habitat may further confound the association. We sought to estimate bobcat population size at a landscape scale (14,286 km2) in central Wisconsin, which provided an opportunity to relate predicted occurrence to individual space use and population density. We sampled bobcats using motion-sensitive trail cameras at 9 arrays across central Wisconsin. We estimated bobcat site-specific occupancy, and regressed these estimates as linear or asymptotic functions of site-specific density to determine the strength and shape of their association. We subsequently modeled both parameters relative to habitat covariates and repeated the regression process. A linear functional relationship between density and occupancy was most supported when detection parameters were held constant (wi= 0.97, R2 = 0.72) and when detection, occurrence, and density were modeled as a function of habitat covariates (wi= 0.99, R2 = 0.95). This suggests that repeated presence-absence data alone may be an efficient and reliable method for inferring spatial patterns in bobcat density or identifying habitat types with greater density potential in the northern parts of its range. Bobcat occupancy and density were both positively associated with surrounding woody cover and wetland edge density. Our most supported spatially explicit capture-recapture model estimated bobcat abundance as 362 adult individuals (95% CI 272–490) across the study area. © 2015 The Wildlife Society.
This document provides an overview of secr 2.3, an R package for spatially explicit capture–recapture analysis (SECR). It includes some background on SECR, an outline of the package, and a more detailed description of how models are implemented. See Appendix 1 for a glimpse of secr in action. For details of how to use secr see the help pages and vignettes.
N UMEROUS distributional accounts of Mexican animals have appeared in recent years, amplifying our understanding of a rich, complex, and highly diverse fauna. Few studies, however, have related local faunas to climatic and vegetation types as outlined by Leopold (1950). By the focusing of study on a single plant formation or vegetation type, rather than on a politi-cal or other nonenvironmental unit, certain zoogeographic problems, such as Pleistocene influences on distribution patterns, are opened to investigation. The following account illustrates an application of this viewpoint. In northeastern Mexico two small ranges, the Sierra San Carlos and Sierra de Tamaulipas, rise from the Tamaulipan Coastal Plain, completely isolated from the abrupt escarpment of the Sierra Madre Oriental. The higher parts of these ranges are covered by belts of open pine-oak woods, similar in structure and presumably in climate, to extensive forests of this nature in the adjacent Sierra Madre. They are isolated from the latter and from each other by the arid tropical thorn forest and thorn scrub of the intervening coastal plain (map l), and thus constitute environmental islands for species inhabiting the pine-oak formation. The coastal plain Sierras have been visited by comparatively few collectors and no fauna1 reports have appeared beyond that of Dice (1937) and others on the Sierra San Carlos. The pine-oak avifauna of the Sierra Madre Oriental in northeastern Mexico is somewhat better known and appears fairly homo-geneous, judging from published accounts (Burleigh and Lowery, 1942; Harrell, MS; Phillips, 1911; R o b ins and Heed, 1951; Sutton and Burleigh, 1939; Sutton and Pettingill, 1943; Sutton, Pettingill, and Lea, 1942). Our preliminary fauna1 survey of the Sierra de Tamaulipas has been compared with these in viewing the relationships between the pine-oak areas of north-eastern Mexico.
Land use/cover change (LUCC) modeling is an important approach to evaluating global biodiversity loss and is the topic of a wide range of research in ecology, geography and environmental social science. This paper reports on development and assessment of maps of change potential produced by two spatially explicit models and applied to a Tropical Deciduous Forest in western Mexico. The first model, DINAMICA EGO, uses the weights of evidence method which generates a map of change potential based on a set of explanatory variables and past trends involving some degree of expert knowledge. The second model, Land Change Modeler (LCM), is based upon neural networks. Both models were assessed through Relative Operating Characteristic and Difference in Potential. At the per transition level, we obtained better results using DINAMICA. However, when the per transition susceptibilities are combined to compose an overall change potential map, the map generated using LCM is more accurate because neural networks outputs are able to express the simultaneous change potential to various land cover types more adequately than individual probabilities obtained through the weights of evidence method. An analysis of the change potential obtained from both models, compared with observed deforestation and selected biodiversity indices (species richness, rarity, and biological value) showed that the prospective LUCC maps tended to identify locations with higher biodiversity levels as the most threatened areas as opposed to areas that had actually undergone deforestation. Overall however, the approximate assessment of biodiversity given by both models was more accurate than a random model.
Las poblaciones remanentes de ocelotes (Leopardus pardalis albescens) en los Estados Unidos se encuentran reducidas a dos poblaciones aisladas en el sur de Texas, con la población más cercana a estas en Tamaulipas central, México. La especie se considera amenazada y la recuperación de las poblaciones de Texas podría, eventualmente, requerir la traslocación de individuos desde poblaciones más grandes. Secuenciamos la región de control del ADN mitocondrial de individuos de Texas y el norte de México y comparamos estos datos con secuencias existentes de otras áreas de distribución del ocelote en México, América Central y América del Sur. La diversidad nucleótida fue más baja en Texas que en México, lo que sugiere pérdida de variabilidad genética como consecuencia de fragmentación y elevada deriva genética. Análisis filogenéticos mostraron una relación estrecha entre poblaciones en Texas y el norte de México que incluyen el área de distribución de la subespecie L. pardalis albescens. En base a estos datos, la mejor población fuente para un plan de recuperación que involucre traslocación de ocelotes sería la del norte de México porque esta región parece formar una unidad de manejo distinta (tanto ecológica como filogenéticamente) que incluye a Texas.
Dos fotografías de ocelotes (Leopardus pardalis) fueron obtenidas en Sierra Fría, Aguascalientes, México. Estos registros amplían la distribución geográfica conocida de la especie alrededor de 270 km al este de Nayarit y 300 km al noroeste de Guanajuato.
Ocelots (Leopardus pardalis) are listed as endangered federally and by the state of Texas. Preference for closed canopy habitat has been shown in previous studies, but preference for patch size has not been reported. Geographic Information Systems (GIS) and satellite imagery were used to compare areas in south Texas used by radio-collared ocelots to areas with no known use. We hypothesized that ocelots would prefer large patches of closed canopy habitat and avoid large patches of unsuitable habitat. Areas used by ocelots had a greater degree of fragmentation (i.e., larger number of patches, smaller size, and more edge) than did those not used. Further investigation revealed that ocelots preferred patches of closed canopy over other types of land cover and that this land cover type exhibited a greater degree of fragmentation. Results of this study were used to designate areas for conservation of ocelot habitat and can be applied to the management of other threatened or endangered wildlife.
The Sierra de Tamaulipas is a biogeographically isolated mountain system in Northern Mexico, where habitat fragmentation by land-management practices is a possible threat to wildlife conservation. As a case example, we used GIS analyses to evaluate how human activities influence the landscape structure of jaguar (Panthera
onca) habitat in the region. The study: (1) ranked potential habitat based on associations between environmental attributes (topography, streams and vegetation) and the frequency distribution of jaguar sighting records; (2) classified current land cover from a 1990 Landsat-TM image and mapped the landscape structure of high potential habitat; and (3) compared the degree to which mature natural vegetation is fragmented by different types of owners. Jaguar sites showed significant associations with tropical deciduous and oak forests, and low, west or south-east slopes, between 400 and 900 m. About 52% of the high potential habitat was mapped as mature natural vegetation, which was distributed as two large patches (28% of the land area) and many small forest patches (98% at < 80 ha). The number and size-class distribution of high-potential habitat patches varied little amongst four ownership types, but the dispersed distribution of more subsistence and commercial-based owners across the landscape suggests the need for collaborative participation in a conservation plan. From our study the need to scale up from managing individual land parcels is substantiated and areas that promote regional contiguity of jaguar habitat in the Sierra de Tamaulipas are identified.