Among species, coexistence is driven partly by the partitioning of available resources. The mechanisms of coexistence and competition among species have been a central topic within community ecology, with particular focus on mammalian carnivore community research. However, despite growing concern regarding the impact of humans on the behaviour of species, very little is known about the effect of humans on species interactions. The aim of this review is to establish a comprehensive framework for the impacts of human disturbance on three dimensions (spatial, temporal and trophic) of niche partitioning within carnivore communities and subsequent effects on both intraguild competition and community structure. We conducted a systematic review of the literature on carnivore niche partitioning (246 studies) and extracted 46 reported effects of human disturbance. We found evidence that human disturbance impacts resource partitioning, either positively or negatively, in all three niche dimensions. The repercussions of such variations are highly heterogeneous and differ according to both the type of human disturbance and how the landscape and/or availability of resources are affected. We propose a theoretical framework of the three main outcomes for the impacts of human disturbance on intraguild competition and carnivore community structure: (i) human disturbance impedes niche partitioning, increasing intraguild competition and reducing the richness and diversity of the community; (ii) human disturbance unbalances niche partitioning and intraguild competition, affecting community stability; and (iii) human disturbance facilitates niche partitioning, decreasing intraguild competition and enriching the community. We call for better integration of the impact of humans on carnivore communities in future research on interspecific competition.

Abundance and density are vital metrics for assessing a species’ conservation status and for developing effective management strategies. Remote‐sensing cameras are being used increasingly as part of citizen science projects to monitor wildlife, but current methodologies to monitor densities pose challenges when animals are not individually recognizable. We investigated the use of camera traps and the Random Encounter Model (REM) for estimating the density of West European hedgehogs (Erinaceus europaeus) within a citizen science framework. We evaluated the use of a simplified version of theREMin terms of the parameters’ estimation (averaged vs. survey‐specific) and assessed its potential application as part of a large‐scale, long‐term citizen science project. We compared averagedREMestimates to those obtained via spatial capture–recapture (SCR) using data from nocturnal spotlight surveys. There was a high degree of concordance inREM‐derived density estimates from averaged parameters versus those derived from survey‐specific parameters. AveragedREMdensity estimates were also comparable to those produced bySCRat eight out of nine sites; hedgehog density was 7.5 times higher in urban (32.3 km⁻²) versus rural (4.3 km²) sites. Power analyses indicated that the averagedREMapproach would be able to detect a 25% change in hedgehog density in both habitats with >90% power. Furthermore, despite the high start‐up costs associated with theREMmethod, it would be cost‐effective in the long term. The averagedREMapproach is a promising solution to the challenge of large‐scale and long‐term species monitoring. We suggest including theREMas part of a citizen science monitoring project, where participants collect data and researchers verify and implement the required analysis.

Several large carnivore populations are recovering former ranges, and it is important to understand interspecific interactions between overlapping species. In Scandinavia, recent research has reported that brown bear presence influences gray wolf habitat selection and kill rates. Here, we characterized the temporal use of a common prey resource by sympatric wolves and bears and described individual and seasonal variation in their direct and/or indirect interactions. Most bear–wolf interactions were indirect, via bear scavenging of wolf kills. Bears used >50% of wolf kills, whereas we did not record any wolf visit at bear kills. Adult and subadult bears visited wolf kills, but female bears with cubs of the year, the most vulnerable age class to conspecifics and other predators, did not. Wolf and bear kill rates peaked in early summer, when both targeted neonate moose calves, which coincided with a reduction in bear scavenging rate. Some bears were highly predatory and some did not kill any calf. Individual and age-class variation (in bear predation and scavenging patterns) and seasonality (in bear scavenging patterns and main prey availability of both wolves and bears) could mediate coexistence of these apex predators. Similar processes likely occur in other ecosystems with varying carnivore assemblages.

Technologies to monitor species are constantly evolving including the use of acoustic recordings to determine species presence, activity patterns and population dynamics. The Acoustic Complexity Index (ACI) aims to determine ecologically relevant changes in the soundscape by measuring the variability within biotic sounds whilst remaining insensitive to anthrophony. Previous findings relating to this index and its correlations with avian species richness and diversity, environmental and anthropogenic factors were amalgamated in this review to guide the future use of this monitoring technique. A total of 25 papers were returned following a literature search in June 2020 targeting studies in which these relationships were analysed. Current literature shows inconclusive relationships between the ACI and avian species richness and diversity. Also, those studies analysing relationships between the index, environmental and anthropogenic factors provided contrasting results due to the lack of replication between studies. The future implementation of a standardised approach towards data collection should lead to more compelling conclusions. Relationships between the soundscape and the environment should be evaluated on an individual site basis due to the influence species composition has on the acoustic environment. Further study is required to determine the relationship between anthropogenic factors, the ACI and avian assemblages.