The mainland clouded leopard Neofelis nebulosa is categorized as Vulnerable on the IUCN Red List and considered at high risk of extinction in the wild. Despite this, knowledge of its ecology and population status remains limited. We investigated the population density, habitat utilization and spatial and temporal ecology of the clouded leopard in Manas National Park, north-east India. We deployed camera traps across the forested habitats of Manas for 11,388 trap-nights, resulting in images of 12 clouded leopard individuals. The estimated population density was 1.73 individuals per 100 km2 and the relative abundance index was 0.18 per 100 trap-nights. The availability of small prey species and primary forests influenced clouded leopard habitat use significantly, highlighting the potential conservation importance of species such as hares, gallinaceous birds, porcupines and primates. We observed a high degree of temporal overlap (> 0.70), with distinct activity peaks, between clouded leopards and sympatric carnivores. We observed no spatial co-occurrence pattern between clouded leopards and sympatric carnivores. This study contributes to our understanding of the mainland clouded leopard population and its behavioural ecology in Manas National Park.

One of the multiple threats to protected areas worldwide, invasive plant species have the potential to decrease biodiversity and ecosystem function. We studied changes in infestation by two widespread invasive plant species – Chromolaena odorata and Mikania micrantha – in India’s Manas National Park, a critical conservation site for threatened flora and fauna. Based on field surveys in 2011 and 2019, we found that C. odorata and M. micrantha were present in most of the sampled plots and had newly invaded over 20% of the plots. However, the abundance of M. micrantha decreased in 45% of the plots while C. odorata increased in >50% of the plots. We used a decision tree-based regression with environmental variables as predictors to generate the distribution, abundance and invasion risk maps of the two species. Among environmental variables, road proximity and fire frequency had the strongest influences, respectively, on C. odorata and M. micrantha. Invaded quadrats exhibited lower native-plant diversity than non-invaded quadrats, and C. odorata specifically had a strong negative association with native-plant community structure. These invasive species have increased their range and abundance, and our predicted invasion risk maps indicate the areas where management intervention is urgently needed.

Effective conservation of rare carnivores requires reliable estimates of population density for prioritizing investments and assessing the effectiveness of conservation interventions. We used camera traps and capture–recapture analysis to provide the first reliable abundance and density estimates for the common leopard Panthera pardus and clouded leopard Neofelis nebulosa in Manas National Park, India. In 57 days of camera trapping, with a total of 4,275 camera-trap days, we photo-captured 27 individually identified common leopards (11 males, 13 females and three unidentified), and 16 clouded leopards (four males, five females and seven unidentified). The abundance estimates using the M h jackknife and Pledger model M h were 47.0 and 35.6, respectively, for the common leopard, and 21.0 and 25.0, respectively, for the clouded leopard. Density estimates using maximum likelihood spatially-explicit capture–recapture were 3.4 ± SE 0.82 and 4.73 ± SE 1.43 per 100 km2 for the common and clouded leopards, respectively. Spatially-explicit capture–recapture provided more realistic density estimates compared with those obtained from conventional methods. Our data indicates that camera trapping using a capture–recapture framework is an effective tool for assessing population sizes of cryptic and elusive carnivores such as the common and clouded leopards. The study has established a baseline for the long-term monitoring programme for large carnivores in Manas National Park.