Context
Black bear connectivity studies are scarce in the southern distribution where the species is endangered. The identification of corridors is a strategy to promote conservation in ...human-modified landscapes.
Objectives
Assess and validate long-distance corridors in the southern black bear distribution using resistance models, occurrence records, and radio-telemetry of an individual that dispersed between the Sierras Madres of Mexico.
Methods
We acquired black bear occurrence records from several sources and telemetry records from one dispersal individual in northern Mexico. We generated ensemble habitat suitability models and resistance landscape surfaces to generate cumulative resistant kernel and least-cost paths to identify connectivity core areas and corridors of importance through Natural Protected Areas. Finally, we assessed long-distance corridors.
Results
We developed three habitat suitability models for black bears southern range; one matches the current distribution of the species. When including radio-tracking records, the landscape resistance is reduced to arid sites with low habitat suitability. We used least resistance connectivity surfaces to merge subpopulations within each Sierra Madre. The long-distance corridor models indicate narrow routes that require individuals with plastic behavioral dispersal capacity. Almost 20% of the connectivity core areas are within Natural Protected Areas. These are the first large-scale corridors using resistance layers in the southern black bear distribution.
Conclusions
Corridors can be functional for a range of temperate and dry habitat species. Landscape connectivity models should include the monitoring of dispersal individuals to identify the plasticity of organisms and the tangible barriers for them.
One of the most effective means of evaluating the effects of habitat loss and landscape configuration is to assess the response of bioindicators. The present study aimed to verify which parameters of ...ant and dung beetle communities (species richness, abundance, unbiased Shannon diversity, and turnover rates) are most useful for evaluating the relative influence of small forest patches (< 50 ha) and landscape in the tropical rainforest of Los Tuxtlas, Mexico. We recorded a total of 106 species of ants and 30 species of dung beetle. The ant and dung beetle assemblages were related in different ways to patch and landscape attributes. Hypogeic ants were more sensitive to patch attributes, particularly vegetation composition, compared to landscape attributes. Epigeic ant assemblages are likely a disturbance indicator, or the assemblages have already homogenized across the region. Arboreal ant assemblages were particularly sensitive to fragmentation and responded to within-patch vegetation and landscape configuration. Dung beetles were more sensitive to landscape composition than to patch attributes. Given these findings, the biomonitoring of ants and dung beetles should focus on both patch and landscape attributes in fragmented landscapes to maintain the different ecosystem functions provided by them.
Mammals are one of the most negatively affected groups by urbanization, nevertheless, urban reserves can help their conservation. The study of wildlife within the reserves is important for the ...persistence of these populations, but stressors factors as feral fauna might endanger the conservation of wildlife. Therefore, our objective was to analyze the patterns of temporal and spatial activity of wild and feral mammals within the San Angel Pedregal Ecological Reserve, UNAM, Mexico City, using trap cameras. We found five species of wild mammals and two feral ones. All mammals were primarily nocturnal, except for the Rock Squirrel which changes their behavior in comparison with individuals in natural habitats. All wildlife species showed a high temporal overlap of activity with feral fauna particularly, Rock Squirrel, Eastern Cottontail, and Gray Fox. The analysis of spatial co-occurrence showed that the probability of an encounter between species at a certain point of the reservation is random. Although, due to the reduced area of the reserve, species may overlap spatially. In general, our results indicate that feral fauna has a high overlap of activity with wildlife, however, the studied reserve protects wildlife populations. Therefore, to reduce this overlap, we recommend creating a dog and cat management program for urban protected areas and surrounding areas. Particularly in REPSA, we encourage to continue with the control program of feral species in the long term and change the management of waste within the UNAM.
Protected urban green spaces (PUGS) are exposed to numerous disturbances and threats since they are immersed in highly dynamic socio-ecological systems. PUGS in highly urbanized cities require ...particular conservation strategies. Here, we propose an approach for PUGS management which integrates three components: i) scientific knowledge (monitoring/restoration), ii) community interaction with the environment, and iii) management decision. Our hypothesis asserts that the intersection of these components should produce a solid management program, provided that the obtained multidisciplinary knowledge meets the needs of information required by the community and decision makers. We tested this hypothesis for a small PUGS located within Mexico City at the National Autonomous University of Mexico campus that holds the Ecological Reserve of Pedregal de San Ángel. Through a participatory approach we built a mental model to understand the perceptions of different campus actors (students, academics and administrators), and their social and ecological relationships with this PUGS. Our findings provide insight into the actors’ perceptions and concerns and suggest that the interactions among the three components, although important, are not self-generated and must be constructed. The findings also suggest that one of the management problems is the mismatch between scientific knowledge and conservation programs. It is paramount to include generated knowledge into management and monitoring programs. The complexity of the PUGS requires an active collaboration among actors and monitoring the development of management strategies using the three components while taking the conservation goals into account.
Management and conservation strategies for endangered species require information on their temporal and spatial behavioral and habitat use relationships. We evaluated activity patterns and resource ...selection of black bears in northwestern Mexico. We surveyed 29 localities with 1450 camera traps stations from 2009 to 2013 in the states of Sonora and Chihuahua, Mexico. In each locality, we calculated the proportion of diurnal, nocturnal, and crepuscular activity through a kernel density estimator based on the time of independent photographic events, and we built a beta regression between diurnal density and annual temperature, seasonal rainfall (SR), human density, road density, daylight hours, season, and management type. To evaluate resource selection, we built a binomial logistic regression model incorporating Normalized Difference Vegetation Index (NDVI), mean and coefficient of variation of annual temperature, human population density (PD), terrain roughness, and season. Black bear activity was primarily diurnal with a bimodal tendency around sunrise and sunset. Diurnal activity (between sunrise and sunset) was positively influenced by daylight hours, SR, and private reserves and negatively influenced by anthropogenic factors. Resource selection was positively influenced by the coefficient of variation in temperature and NDVI and negatively associated with average annual temperature, PD, and terrain roughness. Activity patterns and resource use were similar to other regions in North America. However, temperature was one of the main factors influencing black bear activity and resource selection in our study areas and should be considered when developing management plans given projected increases in temperature expected under climate change scenarios. We present the first work of its kind for northwestern Mexico and considered it as an important component in future survey and management protocols for the species in the southern portion of its distribution.
The Madrean sky islands of North America, in southern Arizona and adjacent Sonora, harbor a great diversity of vertebrates, but data about the distribution and abundance of mammal species in this ...region are needed to develop strategies for their management and conservation. We used camera traps to record medium and large mammals in 4 sky islands in the state of Sonora, Mexico. We compared species richness and diversity of the 25 species detected: 1) within and outside a natural protected area; 2) according to land use (natural protected area, private property, or conservation area); 3) according to the presence or absence of cattle; and 4) among 7 monitored sites. We found no differences in richness, diversity, and composition of species in our comparative analyses, suggesting homogeneity of the communities. This homogeneity could be the result of the direct or indirect influences of past human impacts in the region, given that federal protection, type of land use, and ranching did not influence the community of medium and large mammals. We discuss the importance of maintaining sites dedicated exclusively to conservation in the region, as well as promoting management at unprotected sites to make predators compatible with livestock and agricultural production.
We present the first systematic checklist of medium and large terrestrial mammals on four mountain ranges known as Sky Islands, in northeastern Sonora, Mexico. We used camera traps for recording ...mammals, with which we documented 25 wild species. Two of the native species are in the IUCN Red List and four are threatened at the national level. We did not document seven wild species with potential distribution at study sites, probably due to limited availability of habitat and/or local extirpation of species. The importance of this work is that we generated an inventory of medium and large mammals in an area considered poorly studied and highly diverse.
The black bear has inhabited North America for three million years. Two clades diverged during this period: coastal and continental; the continental clade includes two subclasses (western and ...eastern). The contact between both is a recent event. Because there is a high genetic differentiation between subclasses, the genetic flow of populations between Sierra Madre Oriental and Sierra Madre Occidental is considered as restricted to nonexistent; also, desert environments and human settlements act as a barrier. There are no recent records of black bears in Durango, so the capture of an individual from there presents the opportunity to test whether there is a possible connection between the populations of Sierra Madre Occidental and Sierra Madre Oriental. Our objective was to determine the geographic origin of this individual and validate whether there is a likely connection between populations from both mountain ranges. A black bear specimen was captured in Felipe Carrillo Puerto, municipality of Guadalupe Victoria, Durango. This specimen was sedated. Tissue samples from ear, hair and excrement were collected; samples of mtDNA were extracted and amplified, and two 418-bp sequences were obtained. The haplotype was characterized by a neutrality test of the control region. To determine the origin of the specimen, GenBank was searched for matches with haplotypes previously described and geographically characterized. Six 418-bp sequences were successfully amplified. The neutrality test yielded a single haplotype, with a 99.32 % agreement with haplotype C. Haplotype C has been previously described for the Trans-Pecos region in Texas; accordingly, this haplotype belongs to the eastern subclade. The origin of the black bear specimen captured was Sierra Madre Oriental, based on the presence of haplotype C. This bear traveled at least 250 km to reach the municipality of Guadalupe Victoria. This displacement event indicates that connectivity between black bear populations from both Sierras Madres has been maintained. This distance is similar to displacements previously reported in fragmented environments where a suitable habitat is surrounded by arid zones. However, this displacement took place between two large mountain ranges, rather than within a single mountain range. Genetic diversity, frequency of displacement events between the Sierras, time and distance between displacements, dispersal routes and presence of patches of suitable habitat, are all factors that should be evaluated in order to understand the current dispersal and genetic-flow patterns between the subspecies of bears in Mexico.
Existe poca información acerca de las poblaciones del jaguar en Sinaloa, México, ya que sólo se cuenta con registros anecdóticos y entrevistas acerca de la presencia de este félido. El objetivo de ...este estudio fue generar información acerca de la abundancia y densidad del jaguar en el área natural protegida Meseta de Cacaxtla. Para detectar al jaguar se usaron trampas cámara. La densidad obtenida fue de 1.59 ind./100 km2 y 15 jaguares para el área natural protegida. Consideramos que el área natural protegida es una región importante para las poblaciones del jaguar de la Sierra Madre Occidental, ya que esta área puede representar un eslabón entre Sahuaripa y la costa de Jalisco.
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