The Danube Clouded Yellow (Colias myrmidone) has experienced one of the most dramatic declines among European butterflies. To estimate genetic diversity in the last population in Poland that has survived in the Knyszyn Forest (KF), we analyzed mitochondrial (COI) and nuclear (EF-1α) polymorphisms in individuals sampled in 2014 and 2022. The results were compared with genetic data obtained in 2014 from a recently extirpated nearby population (Czerwony Bór, CB). Because mtDNA polymorphisms in insects can be modulated by endosymbionts, the samples were screened for Wolbachia. The polymorphism of EF-1α indicated that diversity was gradually decreasing. The KF experienced rapid demographic processes, manifested by a significant change in allele frequency. The small differentiation in nuclear markers between the KF and CB in 2014 suggests that the regional population used to be genetically uniform. Four COI haplotypes that were identified in this study probably belong to two different haplogroups. Wolbachia was detected only in individuals with one specific haplotype, and the prevalence was female-biased, suggesting the induction of two reproductive manipulations. The most common COI haplotype found in Poland was the same as that reported from other parts of Europe, not only for C. myrmidone but also C. caucasica. These results allow us to question the distinctiveness of each taxa.

Knowledge about changes occurring in the genetic structure of populations is extremely important in the case of endangered species. Research studies conducted in space and time allow us to identify factors that are influencing gene flow. Especially in the case of species occurring in the form of dispersed, more or less isolated populations, this is crucial for developing effective conservation strategies. The Carpathians are one of the most important capercaillies stronghold in Central Europe. The population here is fragmented, and at least, some groups of birds are small and isolated. This study aimed to determine whether the genetic structure of the capercaillie in the Polish part of the Carpathians has changed over the last decade. The research was conducted in three Polish national parks: Babia Góra National Park (BAB), Gorce (GOR) and Tatra (TAT). A total of over 1,300 non-invasive samples were collected for genetic analyses in two periods: 2010–2013 and 2021–2022. Individuals were identified using microsatellite markers. It was found that during the research period, there were approximately 200 capercaillie individuals in the Parks. The level of genetic variability in individual strongholds has not changed significantly. However, traces of a new gene pool were found in BAB, which could have appeared from other areas of the Carpathians where the species is being reintroduced. GOR shows features of a sink population: low genetic variability, low number of individuals and gradual decline in emigration. During the period covered by the study, the genetic structure has changed little: the studied strongholds are partially genetically isolated, but gene flow between BAB and GOR appears to be increasingly limited. TAT is a hybrid and transition zone for gene flow between smaller strongholds. The results emphasize the importance of areas with stable, numerous populations for the survival of smaller, peripheral groups of the capercaillie in mountain areas.

Background/Objectives: The black grouse (Lyrurus tetrix) is experiencing a rapid decline across much of Europe. In Poland, the Carpathians and Sudetes constitute two of the last important strongholds of this endangered species; however, the genetic relationships between populations inhabiting these mountain systems remain poorly understood. Methods: A total of 579 non-invasive samples were collected in the Jizera Mountains and Giant Mountains (Sudetes), as well as in the Tatra Mountains and the Orava–Nowy Targ Basin (Carpathians). Microsatellite genotyping at nine loci identified 122 individuals. Genetic diversity and population genetic structure were assessed using F-statistics, AMOVA, STRUCTURE, PCoA and DAPC. Results: Significant genetic differentiation was detected among populations, with substantially lower differentiation within the mountain regions than between the Sudetes and Carpathians. Analyses consistently identified two major genetic groups corresponding to the Sudetes and Carpathians. The highest genetic diversity was recorded in the Tatra Mountains. Some individuals from this population displayed genetic signatures consistent with possible connectivity to neighbouring populations outside the study area, although this hypothesis requires testing with additional reference samples from these populations. Conclusions: The results demonstrate strong genetic structuring of black grouse populations in southern Poland and suggest limited contemporary gene flow between the Sudetes and Carpathians mountain ranges. The observed differentiation supports treating the Sudeten and Carpathian populations as separate Management Units. The Tatra Mountains constitute an important reservoir of genetic diversity and may play a key role in maintaining genetic connectivity within the Carpathian population.