European wildcats (Felis silvestris) are the recent focus of conservation breeding for reintroduction in the UK. Wildlife translocations pose potential disease risks to translocated individuals, sympatric wildlife, livestock and humans.
We conducted disease risk assessment to inform risk mitigation for the proposed Saving Wildcats reintroduction to the Cairngorms National Park area, Scotland, UK.
A four-step process was followed: 1) translocation pathway definition; 2) hazard identification; 3) risk assessment, and 4) risk management and re-evaluation.
The highest risk hazards identified were five infectious diseases; Feline calicivirus, feline immunodeficiency virus, feline parvovirus, feline leukaemia virus and Salmonella species, and three anthropogenic threats; hybridisation with domestic cats, persecution and road traffic accidents.
Implementation of mitigation reduced the assessment of these high risk hazards to either medium or low, with the anthropogenic threats, FIV and starvation remaining the highest risks.
The risk of introducing significant disease to humans, domestic animals, or wildlife by releasing captive-bred wildcats was assessed as low.
Camera trapping associated with capture–recapture models is commonly used to estimate wild felid population density, relying on three main frameworks: spatially explicit capture–recapture (SECR) and two non-spatial approaches (CR-MMDM and CR-hMMDM). Methodological differences, inappropriate sampling designs, and/or insufficient data explain some estimate variability, but the biological factors underpinning this remain undetermined. Prey availability, habitat suitability, and body size may all interact and influence carnivoran population size and density.
We aimed to (1) survey ocelot population density data and summarise information on study designs, methodological approaches, and results, (2) evaluate the relationships between them, (3) disentangle methodological and ecological effects on population density estimates, and (4) provide guidance to improve study design and reporting.
Our systematic review discovered 51 studies reporting 228 ocelot population density estimates from 65 sites across 13 countries. We collated ocelot body mass data (BM) and used forest canopy height (GFCH) as a surrogate for habitat suitability, as well as gross primary productivity seasonality (GPP variation) as a proxy for prey availability. Using a meta-analytical framework, we created models to (1) determine mean ocelot population density in the Neotropics and to assess the effects of (2) methodological and (3) ecological variables on population density estimates.
Mean population density was 20.3/100 km2, with significant differences among methods. SECR and CR-MMDM yielded comparable estimates (16.6/100 km2 and 18.9/100 km2, respectively), while CR-hMMDM produced higher estimates (27.3/100 km2). We found significant positive and negative effects of GFCH and BM, respectively, and a marginally significant negative effect of GPP variation on estimates.
Ocelots thrive in forests with higher canopies, but their population density is limited by local habitat seasonality. Morphological differences further influence variation, with small-bodied populations attaining higher population densities under similar ecological conditions.
Based on our findings, we provide guideline
Sperm whale population units, resident off inhabited islands, are an important source of ecosystem services for local communities and may be subject to greater anthropogenic pressures than their oceanic conspecifics.
The objectives of this review were to identify sperm whale-island specialists' habitats around the world and to assess the level of anthropogenic pressure on such nearshore populations. The hypothesis was that sperm whales with this ecological specialisation are rare and that the negative impacts they experience living close to inhabited shores may be also exacerbated by Anthropogenic Allee effect.
This study was conducted using a systematic literature review, following the principles recommended by the PRISMA guidelines, with a scoping of records of the presence of sperm whale social units in the territorial waters of countries around the world published between 2003 and 2023.
A review of 422 relevant research papers revealed only two places in the world where sperm whales with an island ecological specialisation exist, and there are negative trends in both. Such population units experience cumulative anthropogenic pressures 1.7–1.8 times higher than oceanic ones. The charisma and media popularity of sperm whales, combined with the rarity of observation sites for this species, may increase pressure, potentially accelerating their extinction (Anthropogenic Allee Effect). The results of the study are presented in the form of a narrative synthesis, tables and a map.
Determining the ecological specialisation of sperm whale population units should be a key component of management at both the local and species level. Exploitation of ecosystem services provided by island specialists should be strictly regulated in favour of sustainability, in order to preserve this rare ecological type.
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