Translocations are carried out either unintentionally or intentionally for conservation or management reasons. In both cases, translocated populations may genetically impact natural populations via introgression. Understanding how genetic background may affect an establishment in a novel environment and the potential risks for native populations is important for biodiversity conservation. Here, using a panel of 96 SNPs, we monitor the establishment of two genetically and ecologically distinct brown trout populations released into a mountain lake system in central Sweden where trout did not occur prior to the release. The release was carried out in 1979, and we monitor the establishment over the first three decades (5–6 generations) in seven lakes downstream of the release site. We find that extensive hybridization has occurred, and genes from both populations exist in all lakes examined. Genes from the population that was nonmigratory in its native environment have remained to a higher degree in the area close to the release site, while genes from the population that was more migratory in its native habitat have spread further downstream. All established populations exhibit higher levels of genetic diversity than the released populations. Natural, stream-resident brown trout populations occur ~15 km downstream of the release site and below a waterfall that acts as an upstream migration barrier. Released fish have spread genes to these populations but with low introgression rates of 3%–8%. Recently adopted indicators for monitoring genetic diversity were partly able to detect this introgression, emphasizing the usefulness of genetic indicators in management. The SNP panel used in this study provides a similar picture as previously used allozymes, showing that older marker systems with fewer loci may still be useful for describing the population structure.

Mitigating loss of genetic diversity is a major global biodiversity challenge1, 2, 3-4. To meet recent international commitments to maintain genetic diversity within species5,6, we need to understand relationships between threats, conservation management and genetic diversity change. Here we conduct a global analysis of genetic diversity change via meta-analysis of all available temporal measures of genetic diversity from more than three decades of research. We show that within-population genetic diversity is being lost over timescales likely to have been impacted by human activities, and that some conservation actions may mitigate this loss. Our dataset includes 628 species (animals, plants, fungi and chromists) across all terrestrial and most marine realms on Earth. Threats impacted two-thirds of the populations that we analysed, and less than half of the populations analysed received conservation management. Genetic diversity loss occurs globally and is a realistic prediction for many species, especially birds and mammals, in the face of threats such as land use change, disease, abiotic natural phenomena and harvesting or harassment. Conservation strategies designed to improve environmental conditions, increase population growth rates and introduce new individuals (for example, restoring connectivity or performing translocations) may maintain or even increase genetic diversity. Our findings underscore the urgent need for active, genetically informed conservation interventions to halt genetic diversity loss.

Governments and economic blocs are recognising that the world faces a biodiversity crisis. The restoration of biodiversity to the levels prior to widespread human induced damage has been incorporated as a crucial component of conservation in the Global Biodiversity Framework of the Convention of Biological Diversity. The Nature Restoration Law (NRL) forms part of the European Union's response and after its adoption by the European Parliament and the Council of the European Union, it has formally become the Nature Restoration Regulation (NRR). The NRL aims to play a role in restoring ecosystems, habitats and species but does not expressly include genetic diversity, the third biodiversity component. Considering genetic diversity in strategic biodiversity planning is important to help nature adapt to rapid anthropogenic change. We have reviewed the text of the NRL and note opportunities to incorporate genetic diversity in National Restoration Plans to augment its implementation. In particular, genetic diversity assessments are well aligned with the NRL's aspiration to enhance connectivity, and genetic indicators can assess the effectiveness of its implementation. Here we give examples where restoration has incorporated genetic diversity to ensure long term wide-reaching success. This is of relevance beyond the NRL and applies generally to policy for nature restoration efforts globally, especially those related to the Global Biodiversity Framework.

Biodiversity, including genetic diversity, is the foundation of ecosystems and supports the well-being of all organisms, including humans. Determining how the marine environment shapes genetic diversity and developing best practices to conserve it requires a multi-disciplinary approach that incorporates genomic and environmental information. Seascape genetics and genomics combine spatially resolved ecological, genomic, and environmental data, coupled with modeling to explore past, present, and future patterns of diversity and connectivity. Seascape genetics and genomics provide scientists and managers with a multi-faceted tool that can be applied across a wide range of species and incorporated into marine spatial management. Despite the proven importance of genetic diversity for species resilience, the incorporation of genetic and genomic data is grossly underrepresented in policy, decision-making, and conservation measures. Here, we aim to support the understanding and access to information on seascape genetics and genomics for conservation and environmental management practitioners. We explain how integrating environment, space, traits, and genetics or genomics can advance marine spatial management. We use two advanced case studies to outline methodology and concepts of seascape genomics and the respective policy context, although management uptake is still pending. Lastly, we review the present status of seascape genomics research and discuss challenges, strengths, and future opportunities by providing a road map. We present a successful management uptake case study that could aid the integration of seascape genomics into biodiversity management.

Salmonids have a remarkable ability to form sympatric morphs after postglacial colonisation of freshwater lakes. These morphs often differ in morphology, feeding and spawning behaviour. Here, we explored the genetic basis of morph differentiation in Arctic charr (n = 283) by first establishing a high-quality reference genome and then using this in whole genome sequencing of distinct morphs present in two Norwegian and two Icelandic lakes. The four lakes represent the spectrum of genetic differentiation between morphs from one lake with no genetic differentiation between morphs, implying phenotypic plasticity, to two lakes with locus-specific genetic differentiation, implying incomplete reproductive isolation, and one lake with strong genome-wide divergence consistent with complete reproductive isolation. As many as 12 putative inversions ranging from 0.45 to 3.25 Mbp in size segregated among the four morphs present in one lake, Thingvallavatn, and these contributed significantly to the genetic differentiation among morphs. None of the putative inversions were found in any of the other lakes, but there were cases of partial haplotype sharing in similar morph contrasts in other lakes. Our findings are consistent with a highly polygenic basis of morph differentiation with population-specific selection on alleles linked to the development of similar morph phenotypes. The results support a model where morph differentiation is first established through phenotypic plasticity, leading to niche expansion and separation. This may be followed by gradual development of reproductive isolation, locus-specific differentiation and eventually complete reproductive isolation and genome-wide divergence.

Molecular tools are increasingly applied for assessing and monitoring biodiversity and informing conservation action. While recent developments in genetic and genomic methods provide greater sensitivity in analysis and the capacity to address new questions, they are not equally available to all practitioners: There is considerable bias across institutions and countries in access to technologies, funding, and training. Consequently, in many cases, more accessible traditional genetic data (e.g., microsatellites) are still utilized for making conservation decisions. Conservation approaches need to be pragmatic by tackling clearly defined management questions and using the most appropriate methods available, while maximizing the use of limited resources. Here we present some key questions to consider when applying the molecular toolbox for accessible and actionable conservation management. Finally, we highlight a number of important steps to be addressed in a collaborative way, which can facilitate the broad integration of molecular data into conservation. Molecular tools are increasingly applied in conservation management; however, they are not equally available to all practitioners. We here provide key questions when establishing a conservation genetic study and highlight important steps which need to be addressed when these tools are globally applied.image

Effective population size (Ne) is one of the most important parameters in evolutionary biology, as it is linked to the long-term survival capability of species. Therefore, Ne greatly interests conservation geneticists, but it is also very relevant to policymakers, managers, and conservation practitioners. Molecular methods to estimate Ne rely on various assumptions, including no immigration, panmixia, random sampling, absence of spatial genetic structure, and/or mutation-drift equilibrium. Species are, however, often characterized by fragmented populations under changing environmental conditions and anthropogenic pressure. Therefore, the estimation methods' assumptions are seldom addressed and rarely met, possibly leading to biased and inaccurate Ne estimates. To address the challenges associated with estimating Ne for conservation purposes, the COST Action 18134, Genomic Biodiversity Knowledge for Resilient Ecosystems (G-BiKE), organized an international workshop that met in August 2022 in Brașov, Romania. The overarching goal was to operationalize the current knowledge of Ne estimation methods for conservation practitioners and decision-makers. We set out to identify datasets to evaluate the sensitivity of Ne estimation methods to violations of underlying assumptions and to develop data analysis strategies that addressed pressing issues in biodiversity monitoring and conservation. Referring to a comprehensive body of scientific work on Ne, this meeting report is not intended to be exhaustive but rather to present approaches, workshop findings, and a collection of papers that serve as fruits of those efforts. We aimed to provide insights and opportunities to help bridge the gap between scientific research and conservation practice.

Genetic diversity is essential for maintaining healthy populations and ecosystems. Several approaches have recently been developed to evaluate population genetic trends without necessarily collecting new genetic data. Such “genetic diversity indicators” enable rapid, large-scale evaluation across dozens to thousands of species. Empirical genetic studies, when available, provide detailed information that is important for management, such as estimates of gene flow, inbreeding, genetic erosion and adaptation. In this article, we argue that the development and advancement of genetic diversity indicators is a complementary approach to genetic studies in conservation biology, but not a substitute. Genetic diversity indicators and empirical genetic data can provide different information for conserving genetic diversity. Genetic diversity indicators enable affordable tracking, reporting, prioritization and communication, although, being proxies, do not provide comprehensive evaluation of the genetic status of a species. Conversely, genetic methods offer detailed analysis of the genetic status of a given species or population, although they remain challenging to implement for most species globally, given current capacity and resourcing. We conclude that indicators and genetic studies are both important for genetic conservation actions and recommend they be used in combination for conserving and monitoring genetic diversity.

National, subnational, and supranational entities are creating biodiversity strategy and action plans (BSAPs) to develop concrete commitments and actions to curb biodiversity loss, meet international obligations, and achieve a society in harmony with nature. In light of policymakers' increasing recognition of genetic diversity in species and ecosystem adaptation and resilience, this article provides an overview of how BSAPs can incorporate species' genetic diversity. We focus on three areas: setting targets; committing to actions, policies, and programs; and monitoring and reporting. Drawing from 21 recent BSAPs, we provide examples of policies, knowledge, projects, capacity building, and more. We aim to enable and inspire specific and ambitious BSAPs and have put forward 10 key suggestions mapped to the policy cycle. Together, scientists and policymakers can translate high level commitments, such as the Convention on Biological Diversity's Kunming-Montreal Global Biodiversity Framework, into concrete nationally relevant targets, actions and policies, and monitoring and reporting mechanisms.

Genetic diversity is fundamental to the adaptive potential and survival of species. Although its importance has long been recognized in science, it has a history of neglect within policy, until now. The new Global Biodiversity Framework recently adopted by the Convention on Biological Diversity, states that genetic diversity must be maintained at levels assuring adaptive potential of populations, and includes metrics for systematic monitoring of genetic diversity in so called indicators. Similarly, indicators for genetic diversity are being developed at national levels. Here, we apply new indicators for Swedish national use to one of the northernmost salmonid fishes, the Arctic charr (Salvelinus alpinus). We sequence whole genomes to monitor genetic diversity over four decades in three landlocked populations inhabiting protected alpine lakes in central Sweden. We find levels of genetic diversity, inbreeding and load to differ among lakes but remain stable over time. Effective population sizes are generally small (< 500), suggesting a limited ability to maintain adaptive variability if genetic exchange with nearby populations became eliminated. We identify genomic regions potentially shaped by selection; SNPs exhibiting population divergence exceeding expectations under drift and a putative selective sweep acting within one lake to which the competitive brown trout (Salmo trutta) was introduced during the sampling period. Identified genes appear involved in immunity and salinity tolerance. Present results suggest that genetically vulnerable populations of Arctic charr have maintained neutral and putatively adaptive genetic diversity despite small effective sizes, attesting the importance of continued protection and assurance of gene flow among populations.