Significance: Despite the critical threat of habitat fragmentation, global patterns of fragmentation and its relationship to extinction risk have not been quantified for any major taxon. We developed high-resolution models that provide a global assessment of the degree of habitat fragmentation impacting the world’s terrestrial mammals. Results demonstrate that mammals with more fragmentation are at greater risk of extinction, even after accounting for the effects of key macroecological predictors, such as body size and geographic range size. Species with higher fragmentation had smaller ranges and a lower proportion of high-suitability habitat within their range, and most high-suitability habitat occurred outside of protected areas, further elevating extinction risk. Quantification of habitat fragmentation will help guide strategic priorities for global mammal conservation.

Abundance estimation of carnivore populations is difficult and has prompted the use of non-invasive detection methods, such as remotely-triggered cameras, to collect data. To analyze photo data, studies focusing on carnivores with unique pelage patterns have utilized a mark-recapture framework and studies of carnivores without unique pelage patterns have used a mark-resight framework. We compared mark-resight and mark-recapture estimation methods to estimate bobcat (Lynx rufus) population sizes, which motivated the development of a new "hybrid" mark-resight model as an alternative to traditional methods. We deployed a sampling grid of 30 cameras throughout the urban southern California study area. Additionally, we physically captured and marked a subset of the bobcat population with GPS telemetry collars. Since we could identify individual bobcats with photos of unique pelage patterns and a subset of the population was physically marked, we were able to use traditional mark-recapture and mark-resight methods, as well as the new “hybrid” mark-resight model we developed to estimate bobcat abundance. We recorded 109 bobcat photos during 4,669 camera nights and physically marked 27 bobcats with GPS telemetry collars. Abundance estimates produced by the traditional mark-recapture, traditional mark-resight, and “hybrid” mark-resight methods were similar, however precision differed depending on the models used. Traditional mark-recapture and mark-resight estimates were relatively imprecise with percent confidence interval lengths exceeding 100% of point estimates. Hybrid mark-resight models produced better precision with percent confidence intervals not exceeding 57%. The increased precision of the hybrid mark-resight method stems from utilizing the complete encounter histories of physically marked individuals (including those never detected by a camera trap) and the encounter histories of naturally marked individuals detected at camera traps. This new estimator may be particularly useful for estimating abundance of uniquely identifiable species that are difficult to sample using camera traps alone.

Although lentiviruses similar to feline immunodeficiency virus (FIV) are known to infect numerous felid species, the relative utility of assays used for detecting lentiviral infection has not been compared for many of these hosts. We tested bobcats (Lynx rufus), pumas (Felis concolor), and ocelots (Leopardus pardalis) for exposure to lentivirus using five different assays: puma lentivirus (PLV), African lion lentivirus (LLV), and domestic cat FIV-based immunoblots, a commercially available enzyme-linked immunosorbent assay (ELISA) kit, and nested polymerase chain reaction (PCR). Puma lentivirus immunoblots identified more seropositive individuals than the other antibody-detection assays. The commercial ELISA provided a fair ability to recognize seropositive samples when compared with PLV immunoblot for screening bobcats and ocelots, but not pumas. Polymerase chain reaction identified fewer positive samples than PLV immunoblot for all three species. Immunoblot results were equivalent whether the sample tested was serum, plasma, or whole blood. The results from this study and previous investigations suggest that the PLV immunoblot has the greatest ability to detect reactive samples when screening wild felids of North America and is unlikely to produce false positive results. However, the commercial ELISA kit may provide an adequate alternative for screening of some species and is more easily adapted to field conditions.

The colonization of suitable yet unoccupied habitat due to natural dispersal or human introduction can benefit recovery of threatened species. Predicting habitat suitability and conflict potential of colonization areas can facilitate conservation planning. Planning for reintroduction of gray wolves (Canis lupus) to the US state of Colorado is underway. Assessing which occupancy sites minimize the likelihood of human–wolf conflict during dispersal events and seasonal movements is critical to the success of this initiative. We used a spatial absorbing Markov chain (SAMC) framework, which extends random walk theory and probabilistically accounts for both movement behaviour and mortality risk, to compare the viability of potential occupancy sites (public lands >500 km² to minimally meet wolf pack range area). The SAMC framework produced spatially explicit predictions of wolf dispersal, philopatry and conflict risk ahead of recolonization prior to reintroduction efforts. Our SAMC model included: (1) movement resistance based on terrain, roads and housing density; (2) mortality risk and potential conflict (absorption) based on livestock presence, social tolerance, land ownership and state boundaries; and (3) site fidelity based on habitat quality. Using this model, we compared 21 public land units by deriving predictions of: (A) relative survival time outside each site, (B) intensity of use and retention time within each site and (C) the probability of use on adjacent public lands. We also predicted and mapped potential conflict hotspots associated with each site. Among the units assessed, a complex of USFS Wilderness areas near Aspen, chiefly the Hunter‐Fryingpan and Collegiate Peaks Wilderness areas, had the best overall rankings when comparing predictions of each metric. The area balances high‐quality, well‐connected habitat with relatively low livestock density and high social tolerance. Synthesis and applications. Our findings highlight the utility of the SAMC framework for assessing colonization areas and the capacity to identify locations for effective proactive management, especially of conflict prone species. The flexibility of the SAMC framework enables predicting likely areas of philopatry and human–wildlife conflict using spatially explicit metrics which can improve the success of conservation translocations and management of species with changing geographic extents.