Using population viability analysis, genomics, and habitat suitability to forecast future population patterns of Little Owl Athene noctua across Europe

A probabilistic epidemiological model for infectious diseases: The case of COVID-19 at global-level

This study has developed a probabilistic epidemiological model a few weeks after the World Health Organization declared COVID-19 a pandemic (based on the little data available at that time). The aim was to assess relative risks for future scenarios and evaluate the effectiveness of different management actions for 1 year ahead. We quantified, categorized, and ranked the risks for scenarios such as business as usual, and moderate and strong mitigation. We estimated that, in the absence of interventions, COVID-19 would have a 100% risk of explosion (i.e., more than 25% infections in the world population) and 34% (2.6 billion) of the world population would have been infected until the end of simulation. We analyzed the suitability of model scenarios by comparing actual values against estimated values for the first 6 weeks of the simulation period. The results proved to be more suitable with a business-as-usual scenario in Asia and moderate mitigation in the other continents. If everything went on like this, we would have 55% risk of explosion and 22% (1.7 billion) of the world population would have been infected. Strong mitigation actions in all continents could reduce these numbers to, 7% and 3% (223 million), respectively. Although the results were based on the data available in March 2020, both the model and probabilistic approach proved to be practicable and could be a basis for risk assessment in future pandemic episodes with unknown virus, especially in the early stages, when data and literature are scarce.

Multiple stressors and data deficient populations; a comparative life-history approach sheds new light on the extinction risk of the highly vulnerable Baltic harbour porpoises (Phocoena phocoena)

Many endangered marine mammal populations are difficult to study, spread out over large areas, and capturing them for branding and research purposes would be unethical. Yet, they are in urgent need for assessment and conservation actions. We suggest collecting data from other more abundant populations of the same species, with careful consideration of body size, age at sexual maturity, and ecological conditions to produce scientifically sound best approximations of vital rates of data deficient endangered populations. The genetically distinct Baltic Sea harbour porpoise population amounts to about 500 animals and is classified as 'Critically Endangered' according to the IUCN red list. Data deficiency on nearly all demographic parameters have precluded systematic investigations of the relative importance of stressors affecting population viability. We took a comparative life history approach and investigated the phenotypic plasticity in somatic and demographic vital rates of seven larger, well studied North Atlantic harbour porpoise populations, enabling us to approximate the missing pieces of the life history of the Baltic population. We parameterized a stochastic, individual-based population model, and performed a population viability analysis for a range of biologically realistic parameter values and scenarios of environmental stressors. The baseline scenario was based on the most representative samples of healthy harbour porpoise populations and challenged with three different levels of bycatches. Due to high levels of endocrine disruptive contaminants observed in Baltic harbour porpoises, we also investigated the effect of a possible reduction in fecundity. Subsequently, the combined effects of bycatches and reduced fecundity were investigated in terms of population growth rate and quasi-extinction risk. The Baltic harbour porpoise population is viable in the baseline scenario without anthropogenic stressors. However, even the lowest estimated bycatch level of 7 individuals per year will lead to a population collapse to ≤50 animals with high probability (0.4-1.0) over the next century, assuming an intermediate or low (<73%) fecundity. Adult survival is of critical importance and mitigation of fishery impacts and reduction of anthropogenic disturbances in the identified main breeding areas are recommended.

Population viability analysis of common marsupials, Didelphis marsupialis and Didelphis virginiana, in a scenario of constant loss of native vegetation

We studied the population viability of two common marsupials, Didelphis marsupialis and Didelphis virginiana, based on field data and published ecological and genetic information. Using the VORTEX v. 10. 2.6 program, a 100-year simulation was performed with 1000 iterations for five populations of D. marsupialis and six of D. virginiana. A low probability of extinction was observed in both species, particularly for D. virginiana (0.000–0.007). Population size is higher considering a metapopulation dynamics approach versus individual populations for the two marsupials: 498.25 individuals for D. marsupialis and 367.41 individuals for D. virginiana. The estimated mean genetic diversity was high for both D. marsupialis (H e  = 0.77–0.78) and D. virginiana (H e  = 0.79–0.82). The survival of both species over time could be expected to increase if a metapopulation dynamics is favored over the coming decades, despite a 1.3% loss rate of forest cover. The monitoring of population size and genetic diversity is highly recommended to validate the trends suggested by the model; this is especially true for D. marsupialis, a species associated with conserved areas that are becoming progressively less abundant. This research provides information on the responses of common mammalian species to environmental changes such as deforestation.

Using population viability analysis, genomics, and habitat suitability to forecast future population patterns of Little Owl Athene noctua across Europe

The agricultural scene has changed over the past decades, resulting in a declining population trend in many species. It is therefore important to determine the factors that the individual species depend on in order to understand their decline. The landscape changes have also resulted in habitat fragmentation, turning once continuous populations into metapopulations. It is thus increasingly important to estimate both the number of individuals it takes to create a genetically viable population and the population trend. Here, population viability analysis and habitat suitability modeling were used to estimate population viability and future prospects across Europe of the Little Owl Athene noctua, a widespread species associated with agricultural landscapes. The results show a high risk of population declines over the coming 100 years, especially toward the north of Europe, whereas populations toward the southeastern part of Europe have a greater probability of persistence. In order to be considered genetically viable, individual populations must count 1,000–30,000 individuals. As Little Owl populations of several countries count <30,000, and many isolated populations in northern Europe count <1,000 individuals, management actions resulting in exchange of individuals between populations or even countries are probably necessary to prevent losing <1% genetic diversity over a 100‐year period. At a continental scale, a habitat suitability analysis suggested Little Owl to be affected positively by increasing temperatures and urban areas, whereas an increased tree cover, an increasing annual rainfall, grassland, and sparsely vegetated areas affect the presence of the owl negatively. However, the low predictive power of the habitat suitability model suggests that habitat suitability might be better explained at a smaller scale.