Relict Populations Research Articles

Corrigendum

Corrigendum

Answers Blowing in the Wind: A Quarter Century of Genetic Studies of Pollination in Oaks

For the past 25 years, the twin tools of highly variable genetic markers (microsatellites) and paternity assignment have provided a powerful approach for investigating pollination patterns in trees, including many Quercus species. Early studies consistently demonstrated surprisingly abundant and extensive long-distance pollen movement in oaks. Indeed, numerous studies showed high levels of pollen immigration (50% or more), even for relatively isolated stands of oaks. Research also characterized fertilization patterns within stands and between hybridizing species in mixed stands. More recent studies have expanded our knowledge of genetic exchange effected by successful pollen movement, identified even more remarkable examples of the distances Quercus pollen can travel, and examined pollination patterns in relictual populations as well as those at the leading edges of range expansion. While the paradigm of long distance pollination continues to hold, a few recent studies that have also revealed the limits of pollen movement, identifying cases of reproductive isolation in extreme situations, where populations are at risk. This review will highlight what has been learned about Quercus pollination, what questions remain, and propose implications for forest management in the face of changing landscapes and climates.

Population genomics and conservation of Gila Trout (Oncorhynchus gilae)

Many salmonid species exist in highly structured and isolated populations, and are susceptible to habitat fragmentation and disturbances. Gila Trout (Oncorhynchus gilae) is a threatened species found in the Southwestern United States, and is managed to preserve relict populations (i.e., lineages) distributed across a fragmented landscape. We evaluated genomic variation within and among remaining lineages of Gila Trout using RADseq to assess how drift and selection have structured populations using neutral and outlier loci. We also examined whether a signature of hybridization was evident in relict populations. Gila Trout lineages were significantly differentiated from one another and were characterized by low effective population sizes. However, most lineages maintained genomic diversity and are potentially adapted to local conditions. Hybridization with non-native Rainbow Trout (O. mykiss) was not detected in any lineage. All lineages have experienced population bottlenecks associated with mortality from drought and severe wildfires. Current management strategies should be reevaluated and adapted to better account for long-term effects of climate change. Specifically, we suggest reconnecting some populations via dendritic stream networks to facilitate natural dispersal in a metapopulation context. This would allow natural genetic mixing on the landscape and potentially increase adaptive potential. Furthermore, genetic rescue should be implemented to preserve integrity of the unique Spruce Creek lineage that is currently compromised by extremely low diversity.

Female-Biased Adult Sex Ratio in Relation to Sex-Specific Adult and First-Year Survival, Fledgling Sex Ratio and Dispersal in a Migratory Passerine

The relative number of adult males to females in a population, the adult sex ratio (ASR), is an important demographic variable in populations, which plays a role in, for instance, mating systems and viability of populations. The origins of variation in ASR between populations are often unclear. A skewed ASR in a local population may result from a skewed sex ratio among fledglings, sex differences in survival or dispersal or a combination of these. Meta-analyses show that ASRs across bird species are mostly male-biased and that male-biased survival is the main contributor to this bias. Here, we examine the origins of a female-biased ASR in a small population (3–24 breeding females in 2007–2017) of a passerine, the Northern Wheatear Oenanthe oenanthe. Because 95% of all fledglings were sexed, 88% of the individuals were colour-banded and because this species is highly philopatric, we could accurately examine: (1) fledgling sex ratio, (2) sex-specific first year and adult apparent survival and (3) sex-specific dispersal. It appeared that survival was not sex-biased for either age cohort but that fledgling sex ratio was male-biased, especially so among late broods. In addition, natal dispersal out of the breeding population was likely male-biased, in contrast to the general pattern of female-bias in avian dispersal. So, perhaps females are more common in our relict population solely because more males disperse from the population than females, without being compensated by male-biased fledgling sex ratio or survival and without compensation from immigrating males. Likely, the population sex ratio (including both adults and young) at the end of the breeding season is male-biased, because of a pronounced male-biased sex ratio among fledglings from late nests. Perhaps this male-bias induces prospecting young males to settle elsewhere to avoid competition next year, but at the same time convinces prospecting females to settle particularly in this area.

Evaluating tree-to-tree competition during stand development in a relict Scots pine forest: how much does climate matter?

Key messageCompetitive interactions change over time and their influence on tree growth is intensified during drought events in marginal Scots pine populations.Competition is a key factor driving forest dynamics and stand structure during the course of stand development. Although the role of neighbourhood competition on stand dynamics has received increasing attention, the response of competition to environmental fluctuations and stand development remains poorly explored. We evaluated changes in competition during stand development in a dry-edge Scots pine relict population located in Central Spain. Typically, tree-to-tree interactions have been investigated through static competition measurements, which usually lack the temporal variation associated to natural forest development and environmental conditions. Here, we assessed how individual and neighbourhood components of competition evolved along a 35-year period, and we related competition dynamics to population structure and drought levels. On six plots, 508 trees were mapped and diameters at breast height (DBH) were measured. Two increment cores were taken from target trees to derive basal area increment (BAI), and neighbourhood was reconstructed back to 1980. Results provide insights into inter-annual variability in competition effects and their role on tree radial growth depending on climatic conditions. From the year 2005 onwards, both individual and neighbourhood components of competition showed a decoupled pattern over time. This effect was particularly pronounced during the extreme drought in 2012, in which the individual component decreased, whereas the neighbourhood component increased. In addition, climatic variability modulated the competition effects during stand development. This approach of evaluating competition dynamics proves to be promising for studying forest stand development and the influence of climate impacts on tree populations subjected to xeric conditions.

Genomic data from the Brazilian sibilator frog reveal contrasting pleistocene dynamics and regionalism in two South American dry biomes

AbstractAimKnowledge about the Neotropical dry formations, particularly the Caatinga, remains rudimentary compared to other biotas in the region. Here we address several biogeographical hypotheses by combining intense geographical and genomic sampling obtained for the Brazilian sibilator frog. We specifically test predictions related to the putative roles of past climate shifts (Pleistocene and Holocene) and local geographical barriers (past and current courses of the São Francisco River, SFR) in causing population differentiation in this species.LocationCaatinga and eastern Cerrado.TaxonBrazilian sibilator frog Leptodactylus troglodytes.MethodsWe sequenced up to ~15,000 single nucleotide polymorphisms for 159 samples from 61 locations. We inferred genetic structure using spatial clustering and examined population sizes through time. We estimated the relationship among populations using phylogenetic reconstruction, estimated historical distributions with ecological niche modelling and inferred demographic history under isolation‐with‐migration models.ResultsGenetic diversity in L. troglodytes corresponds to biome boundaries, with one population in the Cerrado and two populations in the Caatinga, separated by the SFR. Demographic model selection indicates the Caatinga populations expanded since the end of the Pleistocene while the Cerrado population declined. Within the Caatinga, population expansion began earlier and was more extreme in the north. A continuous stability area maintained the two Caatinga populations, which share a common origin and began diverging in the mid‐Pleistocene, first with symmetric gene flow and later under pronounced migration from the north.Main conclusionsWe could not reject a role of past climate change in causing diversification of relictual populations in the Cerrado, but we found no evidence of multiple refuges or long‐term isolation within the Caatinga. Instead, diversification in this biome appears to be caused by the SFR acting as a ‘soft barrier’ that constrains migration over an extended period of time.

Island colonization by a ‘rheophilic’ fish: the phylogeography ofGarra ceylonensis(Teleostei: Cyprinidae) in Sri Lanka

AbstractDespite exhibiting multiple morphological adaptations to living in swiftly flowing water (rheophily), Garra ceylonensis is one of the most widely distributed freshwater fish in Sri Lanka. It is thus an ideal organism to reconstruct the evolutionary history of a widespread, yet morphologically specialized, freshwater fish in a tropical-island setting. We analysed the phylogenetic and phylogeographic relationships of G. ceylonensis based on two mitochondrial and one nuclear genes. G. ceylonensis is shown to be monophyletic, with a sister-group relationship to the Indian species Garra mullya. Our results suggest a single colonization of Sri Lanka by ancestral Garra, in the late Pliocene. This suggests that the Palk Isthmus, which was exposed for most of the Pleistocene, had a hydroclimate unsuited to the dispersal of fishes such as Garra. G. ceylonensis exhibits strong phylogeographic structure: six subclades are distributed as genetically distinct populations in clusters of contiguous river basins, albeit with two exceptions. Our data reveal one or more Pleistocene extirpation events, evidently driven by aridification, with relict populations subsequently re-colonizing the island. The phylogeographic structure of G. ceylonensis suggests inter-basin dispersal largely through headwater capture, likely facilitated by free-swimming post-larvae. The Peninsular-Indian species G. mullya comprises two genetically distinct parapatric clades, which may represent distinct species.

Milium effusum (Poaceae: Poeae: Miliinae): species of systematic and cytological interest with notes on polymorphic nature and cytogeography

Present communication records polymorphic and polyploid nature of the forest grass species M. effusum having wide distribution over different continents and countries. Globally the 4 x plants are widely distributed. The West Himalayan plants, collected at 3000 m alt. and more, are also sporting chromosome number of 2n = 28 based on basic number of x = 7. Further meiotic course analysis of Western Himalayan plants follows diploid like behaviour possibly directed by diploidization. This communication also calls the attention to cytogeography of intraspecific cytotypes of M. effusum, where diploid plants (2n = 14) have also been reported, but only 2 times – from the Kola Peninsula, Russia and from the Switzerland mountains. Perhaps these are relict populations, which deserve to be proved, studied and protected.

Population Structure and Migration Patterns of the Tsetse Fly Glossina fuscipes in Congo-Brazzaville.

Tsetse flies of the palpalis group, particularly Glossina fuscipes, are the main vectors of human African trypanosomiasis or sleeping sickness in Congo-Brazzaville. They transmit the deadly human parasite, Trypanosoma brucei gambiense and other trypanosomes that cause animal trypanosomiasis. Knowledge on diversity, population structure, population size, and gene flow is a prerequisite for designing effective tsetse control strategies. There is limited published information on these parameters including migration patterns of G. fuscipes in Congo-Brazzaville. We genotyped 288 samples of G. fuscipes from Bomassa (BMSA), Bouemba (BEMB), and Talangai (TLG) locations at 10 microsatellite loci and determined levels of genetic diversity, differentiation, structuring, and gene flow among populations. We observed high genetic diversity in all three localities. Mean expected heterozygosity was 0.77 ± 0.04, and mean allelic richness was 11.2 ± 1.35. Deficiency of heterozygosity was observed in all populations with positive and significant F IS values (0.077-0.149). Structure analysis revealed three clusters with genetic admixtures, evidence of closely related but potentially different taxa within G. fuscipes. Genetic differentiation indices were low but significant (F ST = 0.049, P < 0.05), indicating ongoing gene flow countered with a stronger force of drift. We recorded significant migration from all the three populations, suggesting exchange of genetic information between and among locations. Ne estimates revealed high and infinite population sizes in BEMB and TLG. These critical factors should be considered when planning area-wide tsetse control interventions in the country to prevent resurgence of tsetse from relict populations and/or reinvasion of cleared habitats.

The Multiple Origins of Roe Deer Populations in Western Iberia and Their Relevance for Conservation.

Simple SummaryThe Iberian Peninsula is considered a reservoir of genetic diversity and the source for the recolonization of continental Europe by several mammal species, after the last glaciation period. Here, we intended to characterize the genetic patterns and origins of one of those species, the roe deer, through the analysis of different genetic markers, as there is a major knowledge gap about the species’ populations at the western edge of roe deer distribution in the Iberian Peninsula. We found that western Iberia is a diversity hotspot for roe deer, with shared gene pools with other European and Iberian regions, but also with unique genetic elements, particularly the case of the relict population of Peneda Gerês National Park. Due to the distinct genetic diversity that was observed in western Iberian populations, we highlight the importance of these populations as sources of resilience against global changes. Our results provide useful information for the management and conservation of this species in the Iberian Peninsula. We advise transboundary management between Portugal and Spain as a rule, as well as careful evaluation of reintroduction actions, that should take in account the genetic data, in order to maintain the genetic heritage of roe deer in Europe.The roe deer (Capreolus capreolus) is native and widespread in Europe and its phylogeography has been clarified in the last decades. Southern peninsulas are considered as reservoirs of genetic diversity and the source for the recolonization of Europe after the last glacial maximum. Even though roe deer populations have been genetically characterized, there is a major knowledge gap about the populations at the western edge of its distribution. To fill this caveat, and based on mitochondrial and nuclear DNA data, we aim to: (i) characterize the genetic diversity and structure of roe deer in western Iberia; (ii) clarify the origins and phylogeographical affinities of these populations, namely the relict population from Peneda Gerês National Park (PNPG, Portugal) and the likely allochthonous populations from central and south (CS) Portugal; (iii) discuss the implications of our findings for the management and conservation of the roe deer. Three major genetic clusters were inferred based on nuclear genotypes and were structured in a similar way as the three major mtDNA clades present in Iberia. Patterns inferred with nuclear markers confirmed PNPG as a relict population. Roe deer from CS Portugal share haplotypes with Central Europe rather than with other western Iberian populations, confirming its mainly allochthonous origin. Our results highlight western Iberia as a diversity hotspot for roe deer. We highlight the role of intraspecific genetic diversity as a source of resilience against ongoing global changes; the need for transboundary management and the importance of genetic data to inform management and conservation. When considered, repopulation or translocation measures should follow the IUCN Law of Reintroductions and meticulously conducted in order to preserve the genetic heritage of the species.

Heterozygosity-Fitness Correlations in a Continental Island Population of Thorn-Tailed Rayadito.

Heterozygosity-fitness correlations (HFCs) have been used to monitor the effects of inbreeding in threatened populations. HFCs can also be useful to investigate the potential effects of inbreeding in isolated relict populations of long-term persistence and to better understand the role of inbreeding and outbreeding as drivers of changes in genetic diversity. We studied a continental island population of thorn-tailed rayadito (Aphrastura spinicauda) inhabiting the relict forest of Fray Jorge National Park, north-central Chile. This population has experienced a long-term, gradual process of isolation since the end of the Tertiary. Using 10 years of field data in combination with molecular techniques, we tested for HFCs to assess the importance of inbreeding depression. If inbreeding depression is important, we predict a positive relationship between individual heterozygosity and fitness-related traits. We genotyped 183 individuals at 12 polymorphic microsatellite loci and used 7 measures of reproductive success and estimates of apparent survival to calculate HFCs. We found weak to moderate statistical support (P-values between 0.05 and 0.01) for a linear effect of female multi-locus heterozygosity (MLH) on clutch size and nonlinear effects on laying date and fledging success. While more heterozygous females laid smaller clutches, nonlinear effects indicated that females with intermediate values of MLH started laying earlier and had higher fledging success. We found no evidence for effects of MLH on annual fecundity or on apparent survival. Our results along with the long-term demographic stability of the study population contradict the hypothesis that inbreeding depression occurs in this population.

Nowe stanowiska i historia odkrycia Saxifraga paniculata (Saxifragaceae) na Wyżynie Krakowsko-Częstochowskiej

In May 2018, three new populations of Saxifraga paniculata Mill. were found in the Skały Kroczyckie hills in the Wyżyna Krakowsko-Częstochowska Upland (Fig. 1). In Poland, S. paniculata is frequent only in the Tatra Mts and Pieniny Mts in the Western Carpathians; its occurrence in the Wyżyna Krakowsko-Częstochowska Upland consists of relict populations from the Pleistocene glacial (Vistulian). In the Wyżyna Krakowsko-Częstochowska Upland, Saxifraga paniculata occurs in four regions: the Dolina Będkowska valley, Olsztyn village, Podzamcze village and Skały Kroczyckie hills. The oldest locality was found in Olsztyn village by Professor Wojciech Jastrzębowski in 1847. The locality in Ojców village has not been confirmed for more than 150 years. All populations of S. paniculata in the Wyżyna Krakowsko-Częstochowska Upland are strongly endangered due to intensive tourism and rock climbing.

Pleurospermum austriacum (Apiaceae) – nowy górski gatunek we florze Wyżyny Częstochowskiej

In May 2018, Pleurospermum austriacum (L.) Hoffm. was found in the Skały Kroczyckie hills (Wyżyna Częstochowska Upland, S Poland; Fig. 1). The population consisted of 47 plants, including 11 flowering ones, growing in Dentario enneaphyllidis-Fagetum forest. In 2019 only 55 vegetative plants were observed at this locality, probably due to a prolonged spring drought. In Poland, P. austriacum occurs mainly in the Carpathians and Sudetes in tall-herb communities of the class Betulo-Adenostyletea; its occurrence outside mountainous areas consists of relict populations from the Pleistocene glacial (Vistulian). In the last fifty years, more than half of the previously known localities of P. austriacum in the Małopolska Upland and Wyżyna Krakowsko-Częstochowska Upland have disappeared. Climatic changes are considered the main threat to relict lowland populations of P. austriacum in Poland.

Dispersal ability predicts spatial genetic structure in native mammals persisting across an urbanization gradient.

As the rate of urbanization continues to increase globally, a growing body of research is emerging that investigates how urbanization shapes the movement—and consequent gene flow—of species in cities. Of particular interest are native species that persist in cities, either as small relict populations or as larger populations of synanthropic species that thrive alongside humans in new urban environments. In this study, we used genomic sequence data (SNPs) and spatially explicit individual‐based analyses to directly compare the genetic structure and patterns of gene flow in two small mammals with different dispersal abilities that occupy the same urbanized landscape to evaluate how mobility impacts genetic connectivity. We collected 215 white‐footed mice (Peromyscus leucopus) and 380 big brown bats (Eptesicus fuscus) across an urban‐to‐rural gradient within the Providence, Rhode Island (U.S.A.) metropolitan area (population =1,600,000 people). We found that mice and bats exhibit clear differences in their spatial genetic structure that are consistent with their dispersal abilities, with urbanization having a stronger effect on Peromyscus mice. There were sharp breaks in the genetic structure of mice within the Providence urban core, as well as reduced rates of migration and an increase in inbreeding with more urbanization. In contrast, bats showed very weak genetic structuring across the entire study area, suggesting a near‐panmictic gene pool likely due to the ability to disperse by flight. Genetic diversity remained stable for both species across the study region. Mice also exhibited a stronger reduction in gene flow between island and mainland populations than bats. This study represents one of the first to directly compare multiple species within the same urban‐to‐rural landscape gradient, an important gap to fill for urban ecology and evolution. Moreover, here we document the impacts of dispersal capacity on connectivity for native species that have persisted as the urban landscape matrix expands.

Modeling Louisiana Pinesnake Habitat to Guide the Search for Population Relicts

Pituophis ruthveni (Louisiana Pinesnake) is one of the rarest snakes in the United States. Efforts to refine existing habitat models that help locate relictual populations and identify potential reintroduction sites are needed. To validate these models, more efficient methods of detection for this rare species must also be developed. Here we expand recent habitat suitability models based on edaphic factors to include mature Pinus (pine) stands that have not been cut for at least 30 years and likely have vegetation structure with the potential to support the species. Our model identified a total of 1652 patches comprising 180,050 ha of potentially suitable habitat, but only 16 (1%) of these patches were more than 1000 ha and considered worthy of conservation attention as potential reintroduction sites. We also visited potentially suitable habitat, as determined by our model, and used camera traps to survey for relictual populations at 7 areas in Texas. We observed 518 snakes of 18 species in 8,388,078 images taken from April to October 2016, but no Louisiana Pinesnakes were detected. The patchiness of the habitat model and failure to detect Louisiana Pinesnakes corroborate independent conclusions that most populations of the species are small, isolated, probably in decline, and possibly extirpated. In the context of this extreme rarity, we believe this study will help manage limited conservation resources by narrowing the search areas for relictual populations, providing a more cost-effective method of surveying those areas, and identifying the best sites for future reintroduction efforts.

Genetic Consequences of Hybridization in Relict Isolated Trees Pinus sylvestris and the Pinus mugo Complex

Scots pine (Pinus sylvestris L.) and the taxa from the P. mugo complex can hybridize in the contact zones and produce fertile hybrids. A unique example of an early Holocene relict population of P. sylvestris and P. uliginosa (a taxon from the P. mugo complex) growing on the tops of Jurassic sandstone rocks is located in Błędne Skały (Sudetes). Phenotypically, there are trees resembling P. sylvestris, P. uliginosa and intermediate forms between them. We expected that some of P. sylvestris and/or P. uliginosa-like trees could be in fact cryptic hybrids resembling one of the parental phenotypes. To address this question, we examined randomly sampled individuals, using a set of plastid (cpDNA), nuclear (nDNA) and mitochondrial (mtDNA) markers as well as biometric characteristics of needles and cones. The results were compared to the same measurements of allopatric reference populations of the P. sylvestris and the P. mugo complex (Pinus mugo s.s, P. uncinata and P. uliginosa). We detected cpDNA barcodes of the P. mugo complex in most individuals with the P. sylvestris phenotype, while we did not detect cpDNA diagnostic of P. sylvestris within P. uliginosa-like trees. These results indicate the presence of cryptic hybrids of the P. sylvestris phenotype. We found only three typical P. sylvestris individuals that were clustered with the species reference populations based on needle and cone characteristics. Most trees showed intermediate characteristics between P. sylvestris and P. uliginosa-like trees, indicating intensive and probably long-lasting hybridization of the taxa at this area and subsequent gene erosion of parental species.

Woody plant encroachment drives habitat loss for a relict population of a large mammalian herbivore in South America

Woody plant encroachment (WPE) is reshaping the physiognomy of grasslands and savannahs worldwide. At the same time, this habitat conversion is accelerating the loss of associated biodiversity. In general, studies on WPE have focused on abiotic factors, singly or in combination, that trigger this phenomenon. Despite its ecological relevance, very few studies have tackled the effects of WPE-spurred habitat transformation on animal species dependent on relatively open areas such as grasslands and savannas for survival. We studied a relict and almost extinct population of large, herbivorous guanacos ( Lama guanicoe ) in the Gran Chaco region, Santa Cruz department, Bolivia. We tested whether guanacos were using habitats (at particular and distinct stages of WPE) in relation to their availability. Although this species is considered a generalist herbivore. We tested variation in habitat use focusing on two spatial scales. First, at the landscape level, we performed aerial surveys. Second, at the fine scale, we tracked six groups of guanacos for twenty months and documented the various habitats used within their approximate home ranges. At both scales, we performed a Manly-Chesson’s index referring to the standardised proportional use of each habitat divided by the proportional availability of each, with the values for all habitats summing to 1. An index value 1 suggests, respectively, that a habitat is avoided or selected. We found a disproportionate use of open vegetation (scrubland and grassland) by guanacos in relation to habitat availability at both scales. In addition, the current distribution range of the species is restricted to less than 800 km 2 of the approximately 3,000 km² potentially available in 1998. We confirmed a contraction between 1996 and 2006 in the distribution of the local Chacoan guanaco population from the area where guanacos were first monitored towards the Kaa-Iya National Park border. Our results showed that guanacos are restricted to relatively open areas. Furthermore, the observed reduction in the area previously occupied by the species could be the beginning of a distributional shift and potential loss of the guanaco’s geographic range due to habitat replacement. The latter was also reflected in a previous dietary study of this population we found that guanacos largely consumed the native grass A. mendocina (Poaceae), which has shrunk in distribution by 90 % in this region over a 40 year period and is gradually being replaced by an invasive forb, Lippia sp. Therefore, if the overall purpose on evaluating habitat use is to understand the basic requirements to sustain this population of guanacos, we need to highlight the poor quality and acute regression of the current preferred habitat. In this case, habitat structure can have a profound effect on the success of the guanaco population recovery and its long-term establishment. Therefore, we urge researchers and decision makers to look beyond the more direct human-induced pressures on the species, such as hunting, competition with domestic livestock and agricultural development and consider the importance of WPE as a direct driver for habitat loss.

New records of relictual populations of dung beetle species (Coleoptera, Scarabaeidae) in the Atlantic Forest of the&amp;nbsp;Brazilian Northeast

The diversity of dung beetles is still underestimated in northeastern Brazil. Recent collections have revealed new records of the following species: Canthon histrio (Lepeletier de Saint-Fargeau &amp;amp; Audinet-Serville, 1828), Coprophanaeus acrisius (MacLeay, 1819), Coprophanaeus dardanus (MacLeay, 1819), Deltochilum alpercata Silva et al., 2015, Deltochilum brasiliense (Castelnau, 1840), Dichotomius gilletti Valois et al., 2017, Dichotomius iannuzziae Valois et al., 2017, Eurysternus calligrammus Dalman, 1824, Eurysternus parallelus Castelnau, 1840, Oxysternon silenus Castelnau, 1840, and Phanaeus splendidulus (Fabricius, 1781). These records are discussed in light of the known biogeography of each species.

Description of the second instar larva of Thermothrips mohelensis Pelikán (Thysanoptera: Thripidae).

Thermothrips mohelensis Pelikán is an extremely rare thrips found in dry steppe grassland ecosystems (Pelikán 1949, 1995; Ulitzka 2019a). It has been reported from only a few locations and almost always in very low abundance: one female each has been collected in Germany (Ulitzka 2019a), Slovenia (Kucharczyk 2008) and Turkey (Tunç 1992), two females are known from Iran (Mirab-balou Chen 2013), three from Poland (Zawirska 1988; Kucharczyk 2007) and six from Western Russia (Schliephake 1977). Larger series including males and larvae are known only from Czechoslovakia (Pelikán 1949, 1995) and from Yakutia, East Siberia where-besides other specimens-the larvae discussed below have been collected (see Evdokarova Kucharczyk 2020). The fragmented and selective occurrence of this species in steppe habitats has been interpreted to represent scattered relict populations that may have remained from a more extensive distribution far back, possibly in the wide dry grasslands of the Late Pleistocene (Ulitzka 2019a). Similar to other specialist species of those barren habitats T. mohelensis is severely threatened by the general decline of these fragile ecosystems due to natural succession or anthropogenic impact (Kucharczyk 2008; Kucharczyk Kucharcyk 2008; Ulitzka 2019a). T. mohelensis is a thermophilous (zur Strassen 2003) and highly xerophilous species. This thrips was erroneously considered an hydrophilous wetland thrips (Bhatti 1998) due to a mistranslation (see Ulitzka 2019a). T. mohelensis lives and breeds monophagously in flowers of Galium (Rubiaceae), particularly G. verum but also G. mollugo (Pelikán 1949, 1995; Schliephake 1972; Tunç 1992).

Genetic Diversity and Spatial Genetic Structure in Isolated Scots Pine (Pinus sylvestris L.) Populations Native to Eastern and Southern Carpathians

Small, isolated populations are more vulnerable to natural disturbances and loss of genetic diversity. Scots pine, an abundant tree species in the boreal forest of Eurasia, has a scattered natural distribution across Eastern and Southern Carpathian Mountains, where only a few relict populations still exist. We estimated genetic diversity and spatial genetic structure in Scots pine on the basis of microsatellite nuclear markers (nSSR) data. We found a relatively high level of genetic diversity (He = 0.697) within populations and no evidence of recent bottlenecks. Genetic diversity was lower in peat bog populations, as compared to populations that grow on rocky slopes or acidic soils and nutrient-poor sites. Population genetic structure was weak, and genetic discontinuities among populations were detected. Spatial genetic structure (SGS) was observed in nearly all Scots pine populations. The strength of SGS, quantified by Sp statistics, varied greatly among populations, ranging from 0.0011 to 0.0207, with an average of 0.01. Our study highlights that Eastern and Southern Carpathian populations still possess high within-population diversity in spite of the recent fragmentation and reduction of the Scots pine natural distribution range. We discuss the importance of spatial patterns of genetic diversity for developing strategies of conservation and sustainable use of Scots pine genetic resources in the Carpathian region.