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Pathogens can cause host extinction, affect population dynamics and influence natural selection. Host susceptibility to pathogens can vary by species, demographics and genetics which affect epizootic and population dynamics, ultimately determining population trends and evolution.Chronic wasting disease (CWD), a fatal neuro‐degenerative prion disease of cervids, has varying host susceptibility conferred by polymorphisms of the prion protein gene (PRNP) at codon 96 for white‐tailed deer Odocoileus virginianus.Deer with the homozygous Glycine allele (96GG) are most susceptible and a single Serine allele (96GS/96SS) reduces the risk of infection and mortality.We developed epizootiological models that demonstrate CWD infection and disease‐associated mortality were higher for the more susceptible (96GG) genotype; and, infection was higher for males than females. We used population models to evaluate future shifts in genotype frequencies under alternative harvest and infection rate scenarios.Genetic shifts towards less susceptible genotypes were predicted as CWD prevalence increased during the course of an outbreak. This further increased CWD prevalence, and likely environmental contamination from prion shedding, due to longer incubation periods. Alternative harvest management strategies directly influenced CWD prevalence and spread, the rate of genetic selection and deer population growth.Synthesis and applications. We show that chronic wasting disease (CWD) transmission varied by sex, age class and PRNP genotype, and that CWD disease‐associated mortality varied by genotype. Together, these forces lead to CWD‐mediated genetic selection for a white‐tailed deer population. We predict that genetic selection pressure increases when hunter harvest pressure is lowered, and conversely, increasing hunter harvest can reduce genetic selection rates of antlered deer. Our results support the control of CWD prevalence by aggressive harvest of adult males, because they have the highest infection rates. Our results have strong implications for evolution, disease ecology, geographical spread, disease mitigation and cervid population management. [ABSTRACT FROM AUTHOR]

When prevention of invasive species' introductions fails, society faces the challenge to manage invasive species in an effective and efficient way. The success of this depends on biological aspects and on cooperation between decision makers and scientists. Using the case of the round goby Neogobius melanostomus, one of Europe's 'worst invasive species', we propose an approach guiding scientists to co-produce effective and efficient population control measures in collaboration with decision makers., We surveyed the effectiveness, urgency and simplicity perceived by decision makers as well as the support of two population control options: removal of eggs and/or adults. Using a field study and a dynamical population model, we investigated the effectiveness and efficiency for both options in different population contexts., Decision makers initially seemed to lack a clear preference for either control option. After being presented with preliminary field and modelling results, decision makers mostly approved measures being developed to implement the two control options., Starting population control early after detecting the species requires in total fewer years for eradication than controlling an established population: to reach an eradication success rate of 95%, 13 years for early start vs. 18 years for late start are needed when removing eggs and adults; when removing adults only, 20 vs. 29 years are needed. Removing eggs and adults combined results in a yearly effort of 5.01 h/m2, while removing adults only results in a yearly effort of 1.76 h/m2. Thus, removing adults only proves to be the most efficient option to eradicate the population. Nonetheless, considerable effort is needed: when removing less than 57% of the adult population, eradication is not feasible, even assuming low survival and fecundity rates for the population. Furthermore, inflow of new propagules renders eradication efforts ineffective., Synthesis and applications. Scientists who aim to support decision makers in finding an optimal control strategy for invasive species need to be able to provide scientific knowledge on effectiveness and efficiency of different options. For round goby and most non-native species, eradication is only feasible if started early in recently arrived populations and if inflow of new propagules can be prevented. [ABSTRACT FROM AUTHOR]

1. Matrix population models are widely used to describe population dynamics, conduct population viability analyses and derive management recommendations for plant populations. For endangered or invasive species, management decisions are often based on small demographic data sets. Hence, there is a need for population models which accurately assess population performance from such small data sets. 2. We used demographic data on two perennial herbs with different life histories to compare the accuracy and precision of the traditional matrix population model and the recently developed integral projection model (IPM) in relation to the amount of data. 3. For large data sets both matrix models and IPMs produced identical estimates of population growth rate (λ). However, for small data sets containing fewer than 300 individuals, IPMs often produced smaller bias and variance for λ than matrix models despite different matrix structures and sampling techniques used to construct the matrix population models. 4. Synthesis and applications. Our results suggest that the smaller bias and variance of λ estimates make IPMs preferable to matrix population models for small demographic data sets with a few hundred individuals. These results are likely to be applicable to a wide range of herbaceous, perennial plant species where demographic fate can be modeled as a function of a continuous state variable such as size. We recommend the use of IPMs to assess population performance and management strategies particularly for endangered or invasive perennial herbs where little demographic data are available. [ABSTRACT FROM AUTHOR]

1. In a context of increasing human impact on ecosystems and species distributions, population restoration (introductions, reintroductions, reinforcements) is an essential management tool, especially for plant species with limited colonization ability. However, detailed demographic surveys following restoration and comparisons of demographic rates between restored and natural populations, although essential for identifying the key factors of restoration success, are lacking. 2. We compared the demography over 10 years of six natural and two experimentally introduced populations of the narrowly endemic, cliff-dwelling, self-incompatible plant species Centaurea corymbosa. We analysed the fate of two cohorts of individuals that emerged simultaneously from seed introduction and natural germination. We then built a matrix model of population dynamics (using 6 years of data) and compared the demographic rates and asymptotic growth rate between the natural and introduced populations. 3. Overall, survival rates were higher in the introduced than in the natural populations, either due to better habitat conditions at the cliff scale or to better conditions in microsites selected for seed introduction compared to those reached by chance following natural seed dispersal. 4. In contrast, introduced populations exhibited lower fecundity than natural populations, probably due to the introduction protocol which led, in combination with self-incompatibility, to severely reduced mate availability. 5. Despite clear differences in population dynamics between introduced and natural populations, no significant difference in the asymptotic growth rates could be detected, because the higher survival compensated for the lower fecundity in introduced populations. 6. Synthesis and applications. Creating new populations of C. corymbosa in suitable unoccupied sites seems straightforward, provided that the introduction protocol allows sufficiently high fecundity. This key parameter for restoration success can be optimized by sowing seeds from several sources at high density and in several consecutive years, which should increase mate availability for self-incompatible flowering individuals. We suggest that population introduction might be successful for many (endemic) plant species whose geographical range is mainly limited by low colonization ability, especially in Mediterranean landscapes. We show that the simultaneous monitoring of restored and natural populations enables identification of the key parameters to be targeted for management optimization of restored populations. [ABSTRACT FROM AUTHOR]

1. Matrix population models have become important tools in many fields of ecology and conservation biology, and are the most commonly used method in population viability analysis (PVA). There is a large literature concerned with different aspects of matrix model analysis, but relatively little attention has been paid to how data are collected. 2. In most demographic population viability studies, data are sampled in permanent plots, often resulting in poor representation of some stages. It has been suggested that by using previous knowledge of species’ demography it is possible to sample demographic data more efficiently. Here we propose an alternative method that is much simpler and does not rely on any assumptions, namely sampling an equal number of individuals per stage. 3. By using demographic data from 32 species we showed that sampling an equal number of individuals per stage provides more precise estimates of both population growth rate and elasticity than the traditional plot-based method. In some cases it is also better than the estimates gained using the method based on previous knowledge of the species’ demography. The conclusions of the latter method are very sensitive to the quality of the previous knowledge of the species’ demography. In contrast, collecting demographic data from an equal number of individuals per stage is independent of any assumptions. 4. Synthesis and applications. A central aim for management of threatened species is to develop robust and accurate methods for assessing population viability that are also efficient in terms of costs and labour. A key issue is how to collect the data on which viability assessments are based. We show that it is possible to increase considerably the accuracy and robustness of demographic PVA without increasing sampling effort, by using a simple method based on sampling an equal number of individuals per life-cycle stage. Improved PVA model performance will be important to guide conservation efforts and to evaluate different management options. [ABSTRACT FROM AUTHOR]