Genetic signature of immigrants and their effect on genetic diversity in the recently established Scandinavian wolf population

Transboundary connectivity is a key component when conserving and managing animal species that require large areas to maintain viable population sizes. Wolves Canis lupus recolonized the Scandinavian Peninsula in the early 1980s. The population is geographically isolated and relies on immigration to not lose genetic diversity and to maintain long term viability. In this study we address (1) to what extent the genetic diversity among Scandinavian wolves has recovered during 30 years since its foundation in relation to the source populations in Finland and Russia, (2) if immigration has occurred from both Finland and Russia, two countries with very different wolf management and legislative obligations to ensure long term viability of wolves, and (3) if immigrants can be assumed to be unrelated. Using 26 microsatellite loci we found that although the genetic diversity increased among Scandinavian wolves (n = 143), it has not reached the same levels found in Finland (n = 25) or in Russia (n = 19). Low genetic differentiation between Finnish and Russian wolves, complicated our ability to determine the origin of immigrant wolves (n = 20) with respect to nationality. Nevertheless, based on differences in allelic richness and private allelic richness between the two countries, results supported the occurrence of immigration from both countries. A priori assumptions that immigrants are unrelated is non-advisable, since 5.8% of the pair-wise analyzed immigrants were closely related. To maintain long term viability of wolves in Northern Europe, this study highlights the potential and need for management actions that facilitate transboundary dispersal.

Risks and opportunities of assisted colonization: the perspectives of experts

Owing to climate change and other anthropogenic environmental changes, the suitability of locations is changing for many biota that consequently have to adapt in situ or to move to other areas. To mitigate the effects of such pressures, assisted colonization is a conservation tool developed to reduce extinction risks by intentionally moving and releasing an organism outside its native range, and thus, to facilitate tracking changing environmental conditions. This conservation tool has been proposed for threatened animals or plants that presumably cannot adapt in situ or follow environmental changes by dispersal or migration. However, there have been contentious debates about the shortcomings and risks of implementing assisted colonization. For this reason, we evaluated the specific opinions of global experts for assisted colonization on potential risks and opportunities that this approach offers. For this purpose, we used an online survey targeted at authors of scientific publications on assisted colonization. The majority (82%) of the 48 respondents were in favor of applying assisted colonization for species that are at risk of global extinction due to anthropogenic environmental change. Most respondents agreed that assisted colonization should be considered only when other conservation tools are not available and that certain preconditions must be met. Some of these were already highlighted in the IUCN guidelines for assisted colonization and include a completed risk assessment, clearly defined management plans and secured political as well as financial support. The advocacy of assisted colonization in response to anthropogenic global environmental changes was only weakly dependent on the geographic origin of the experts and their working background. Regarding possible risks, most of the respondents were concerned about consequences like failure of the long-term establishment of the translocated species and the transmission of diseases and invasiveness potentially endangering native biota. To keep these risks as low as possible most of the experts agreed that a target area must have a reasonable carrying capacity to sustain a minimum viable population and that adaptive management should be implemented. Careful evaluation of assisted colonization projects is required to generate further evidence that needs to be considered for further developing conservation tools for the Anthropocene.

Assessing the Relative Impacts of Roadkill and Nest Poaching on the Population Viability of the Blue-and-Yellow Macaw, Ara ararauna (Aves: Psittaciformes), in a Brazilian National Park

The blue-and-yellow macaw (Ara ararauna) is suffering from higher roadkill rates (RK) at the Emas National Park (ENP), an important Brazilian National Park in the Cerrado biome. This species is also a victim of nest poaching for illegal trade. We modeled the blue-and-yellow macaw population’s viability in ENP and how this viability is affected by roadkill and nest poaching. We hereby report that the species is critically at risk and could be extinct in about a decade when considering both threats. Without considering any threat, 150 individuals are necessary to maintain a viable population. When individuals are harvested at a roadkill rate of 0.008 individuals/km/year and at twice this level, the viability figures increase to 4500 and 7500 birds, respectively. For nest poaching, we estimated that 2000 individuals are required to maintain a viable population. When both threats are present, 5000 individuals are necessary. The dynamics of the population are highly sensitive to the age at which females reproduce for the first time and the proportion of reproducing adult females, followed by the rate of adult survival. Our model demonstrates how even a non-threatened highly mobile species, such as the blue-and-yellow macaw, may be at risk due to human activities.

Status of a second viable population of the Critically Endangered Delacour's langur in Viet Nam

One of the three Critically Endangered and endemic primate species in Viet Nam, Delacour's langur Trachypithecus delacouri, is restricted to the north of the country. The largest remaining population is in Van Long Nature Reserve, Ninh Binh Province, and the second largest is in nearby Kim Bang Protection Forest, Ha Nam Province, with other populations believed to be too small for recovery. The population in Van Long has been well studied but the status of that of Kim Bang has not previously been adequately evaluated. To address this, a survey was conducted during 10 August–7 October 2018. In total, we recorded 13 groups comprising a total of at least 73 individuals, almost doubling the highest number reported in previous studies. We documented six new groups in Lien Son and Ba Sao communes in Kim Bang. Our findings indicate there is a high likelihood that Delacour's langur population in Kim Bang will recover and could be important for the long-term conservation of this Critically Endangered species. However, immediate and appropriate conservation measures need to be implemented to protect the population from major anthropogenic threats, namely poaching and habitat destruction, detected during our survey.

Behavior of Native Food Isolates of Listeria monocytogenes and Listeria innocua under the Influence of Selected Cultural Attributes and Heat and Cold Treatments

The present investigation assesses the influence of cultural attributes and heat and cold treatments on the behaviour of native toxigenic L. monocytogenes CFR 1302 and non-toxigenic L. innocua CFR 1304 in selected medium. The growth responses of L. monocytogenes and L. innocua under the influencing factors of storage temperature (10-40°C), pH level (5.5-7.5), and storage period (6-48 h) in brain heart infusion and nutrient broths revealed closeness between observed and predicted populations. Response surface plots were generated for the growth behavior of the two test cultures as a function of pH level. The toxigenic L. monocytogenes CFR 1302 could reach a higher viable population. The effect of heat treatment on Listeria spp. in selected five heating menstra showed the lowest D-value of 3.7 min at 60°C for L. innocua CFR 1304 in Milli-Q water to the highest of 8.4 min at 56°C for L. monocytogenes CFR 1302 in skim milk. The average z-value across the heating menstra for L. monocytogenes was 27.3°C as against that of 22°C for L. innocua. In the case of cold treatment, storage of 4 and 8°C resulted in appreciable increase in counts of L. monocytogenes CFR 1302 from the initial inoculum introduced in selected media. At -20°C, there was a slight decrease in the viable population. The research data helps to predict the viable populations of L. monocytogenes as a part of risk assessment in the food chain. This is of significance in providing safe and healthy food to human population.

Can DNA help trace the local trade of pangolins? A genetic assessment of white-bellied pangolins from the Dahomey Gap (West Africa)

We conducted in the Dahomey Gap (DG) a pioneer study on the genetic tracing of the African pangolin trade. We sequenced and genotyped 189 white-bellied pangolins from 18 forests and 12 wildlife markets using one mitochondrial fragment and 20 microsatellites loci. Tree-based assignment procedure showed the 'endemicity' of the pangolin trade, as strictly fed by the lineage endemic to the DG (DGL). DGL populations were characterized by low levels of genetic diversity, an overall absence of equilibrium, inbreeding depression and lack of geographic structure. We identified a 92-98% decline in DGL effective population size 200-500 ya –concomitant with major political transformations along the 'Slave Coast' – leading to contemporaneous estimates inferior to minimum viable population size. Genetic tracing suggested that wildlife markets from the DG sourced through the entire DGL range. Our loci provided the necessary power to distinguish among all the genotyped pangolins, tracing the dispatch of same individuals on the markets and within local communities. We developed an approach combining rarefaction analysis of private allele frequencies and cross-validation with observed data that could trace five traded pangolins to their forest origin, c. 200-300 km away from the markets. Although the genetic toolkit that we designed from traditional markers can prove helpful to trace the pangolin trade, our tracing ability was limited by the lack of population structure within DGL. Given the deleterious combination of genetic, demographic and trade-related factors affecting DGL populations, the conservation status of white-bellied pangolins in the DG should be urgently re-evaluated.

Distribution and threats to Smooth-Coated Otters Lutrogale perspicillata (Mammalia: Carnivora: Mustelidae) in Shuklaphanta National Park, Nepal

This article aims to assess the distribution, threats and perceptions regarding otters in Shuklaphanta National Park (SNP). It also provides an overview of the conservation efforts of the Nepal government within and outside the protected areas. The study was carried out through preliminary survey of the wetlands using direct sighting techniques, plus indirect evidence including fur, spraints, dead remains, pugmarks, transect survey, key informant survey (n= 15), and questionnaire survey of households (n= 70) in buffer zone. This study found that otter signs were mostly concentrated in the moist soil near the wetlands area. Otter distribution was mostly recorded in Radhapur river, Kalikhich lake, Chaudhar river, Hattinala near hattisar area of pipraiya, Bahuni river, Shikari lake, and Salgaudi lake of Shuklaphanta National Park. Fire and extraction of construction materials from wetlands were identified as severe threats through social survey and key informant survey. For the maintenance of viable population of otters these threats should be minimized through effective biodiversity conservation techniques such as awareness programs and enforcement of laws inside the park. In recent decades, the populations have declined as a consequence of hunting and the overall loss of natural habitats. Overall, our study shows that information on the status, distribution and population trends of Smooth-coated Otters is limited. Therefore, we recommend that more studies should be carried out in this region to establish status, distribution and ecology to improve our understanding of otters in the face of increasing impacts on their habitats. In addition, it is mandatory for the implementation of conservation activities such as awareness to the locals and policy makers, appropriate habitat management and initiating scientific research to ensure a minimum viable population of the species in the country.

Měkkýši Přírodní rezervace Prokopské údolí v Praze [Molluscs of the Prokopské údolí Nature Reserve in Prague]

Mollusc fauna of the Prokopské údolí Nature Reserve in Prague (Czech Republic) has been revised. The current research follows up on the monitoring that took place there at five-year intervals in the years 1984–2009. In the 1980s, 43 land snail and seven aquatic species were recorded, while in 2020 the list included 56 land snail and three aquatic species. Although the reserve is considered to be one of the best examined areas in the capital city, remarkable findings are presented, such as a viable population of the critically endangered Helicopsis striata, a new locality of the internationally protected Vertigo angustior, and a recent distant spread of the rare snail Zebrina detrita. Notable trends in the development of local malacofauna in the last four decades are discussed.

Modeling minimum viable population size with multiple genetic problems of small populations

An important goal for conservation is to define minimum viable population (MVP) sizes for long-term persistence. Although many MVP size estimates focus on ecological processes, with increasing evidence for the role of genetic problems in population extinction, conservation practitioners have also increasingly started to incorporate inbreeding depression (ID). However, small populations also face other genetic problems such as mutation accumulation (MA) and loss of genetic diversity through genetic drift that are usually factored into population viability assessments only via verbal arguments. Comprehensive quantitative theory on interacting genetic problems is missing. Here we develop eco-evolutionary quantitative models that track both population size and levels of genetic diversity. Our models assume a biallelic multilocus genome whose loci can be under either a single or interacting genetic forces. In addition to mutation-selection-drift balance (for loci facing ID and MA), we include three forms of balancing selection (for loci where variation is lost through genetic drift). We define MVP size as the lowest population size that avoids an eco-evolutionary extinction vortex after a time sufficient for an equilibrium allele frequency distribution to establish. Our results show that MVP size decreases rapidly with increasing mutation rates for populations whose genomes are only under balancing selection, while for genomes under mutation-selection-drift balance, the MVP size increases rapidly. MVP sizes also increase rapidly with increasing number of loci under the same or different selection mechanisms until a point is reached at which even arbitrarily large populations cannot survive anymore. In the case of fixed number of loci under selection, interaction of genetic problems did not necessarily increase MVP sizes. To further enhance our understanding about interaction of genetic problems, there is need for more empirical studies to reveal how different genetic processes interact in the genome.

Preventing Extinction of a Critically Endangered Dactylorhiza incarnata subsp. ochroleua in Britain Using Symbiotic Seedlings for Reintroduction

The yellow early marsh-orchid (Dactylorhiza incarnata subsp. ochroleuca) is critically endangered in the UK. Reintroduction of this threatened orchid to former haunts that have been restored is a long-term objective of this study. Identifying germination-specific mycorrhizal fungus lineages from closely related species is used as a method due to the extremely small number of plants left in the wild. A putative orchid mycorrhizal fungus of the family Tulasnellaceae, isolated from Dactylorhiza praetermissa, supported in vitro seed germination to produce reintroduction-ready seedlings. Reintroduced symbiotic seedlings survived over the winter months in the flooded reintroduction site (RS). The comparative soil analysis for key nutrients before reintroduction showed that phosphorus content in the RS is very low compared to the soil collected from the wild site (WS) where the last viable population exists. On the other hand, C:N ratio in the soil at the WS and RS were not significantly different. To our knowledge, this is the first-ever report on the reintroduction of symbiotic seedlings of a threatened orchid back to the wild in the UK.