Population genetics and geometric morphometrics of the <Emphasis Type="Italic">Bombus ephippiatus</Emphasis> species complex with implications for its use as a commercial pollinator

Mexico and Central America are among the most biodiverse regions on Earth, harboring many species with high levels of interpopulation morphological and genetic diversity. The mountainous topography of this region contains isolated sky island habitats that have the potential to promote speciation. This has been studied in vertebrates, yet few studies have examined the phylogeographic and genetic structure of insect species encompassing this region. Here we investigate geographic patterns of genetic and morphological divergence and speciation among widespread populations of the highly polymorphic bumble bee Bombus ephippiatus and its closest relative B. wilmattae. We used DNA sequences from a fragment of cytochrome oxidase I (COI), genotypes for twelve microsatellite markers, and morphometric data from wings to construct a well-supported inference of the divergences among these taxa. We have found complex patterns of genetic isolation and morphological divergence within B. ephippiatus across its geographic range and present evidence that B. ephippiatus comprises multiple independent evolutionary lineages. The pattern of their diversification corresponds to geographic and environmental isolating mechanisms, including the Mexican highlands, the lowlands of the Isthmus of Tehuantepec in southern Mexico, the Nicaraguan Depression, the patchily distributed volcanic ranges in Nuclear Central America and Pleistocene glacial cycles. These results have important implications for the development and distribution of B. ephippiatus as a commercial pollinator in Mexico and Central America.     

Assessment of spatial–temporal variation in natural populations of <Emphasis Type="Italic">Brassica incana</Emphasis> in south Italy: implications for conservation

Brassica incana is a secondary-gene pool wild relative of Brassica oleracea. Twenty-two B. incana populations are recorded in Italy, where the species has recently been pointed out as in priority need of conservation. While data on the spatial and temporal variation of B. incana Italian populations are completely lacking, this information is useful in conservation planning for this species. Three populations from the Sorrento peninsula and from the islands of Ischia and Capri, collected in 1984 and 2012, were characterised for 12 morpho-phenological and 21 genetic traits to assess their spatial–temporal variation. The populations were quite different for morpho-phenological and genetic traits. Spatial differentiation was high and easily explained by the isolation. Temporal differentiation between the Sorrento and Ischia populations was high and explained by a reduction in the population census across time, while it was not significant between the two Capri accessions as such pointing to a major effect of genetic drift. Numerical dimension is extremely relevant in evaluating conservation priorities since it has a major impact on population dynamics over time. The Sorrento and Ischia populations are under threat and urgently need conservation actions, suggesting an alarming scenario for the survival of other crop wild relative populations which are similar in census. Our data also show that, in an allogamous and self-incompatible species like B. incana, populations of 100–200 individuals maintain high allelic diversity. According to obtained results, natural populations of species with similar reproductive system and census can be considered at low risk of genetic erosion.     

Molecular phylogeography and population evolution analysis of <Emphasis Type="Italic">Citrus ichangensis</Emphasis> (Rutaceae)

Ichang papeda (Citrus ichangensis), a wild and endemic perennial plant in Rutaceae, is characterized by the existence of wild and natural populations in southwestern and middle-west China. We analyzed a total of 231 individuals across 16 natural populations using chloroplast SSR markers, nuclear SSR markers, and single-copy nuclear genes. Standard population genetic analyses as well as Bayesian and maximum likelihood models were used to clarify the genetic diversity, population differentiation, barriers to gene flow, bottleneck events, isolation by distance, history migration, demographic history among populations, and phylogeny evolution. The chloroplast and nuclear genome analyses revealed a low level of genetic diversity in C. ichangensis. Clear signals of recent bottlenecks and strong patterns of isolation by distance were detected among different subpopulations, indicating a low extent of historical gene flow for this species and that genetic drift would occur after population differentiation. Bayesian clustering analyses revealed a clear pattern of genetic structure, with one cluster spanning the potential refugia in Wuling Mountains and Ta-pa Mountains, and other two clusters covering a more limited distribution range. The demographic history also supported the scenario that two isolated clusters originated in parallel from the genetic diversity center. Taxonomically, Ichang papeda may be a member of subgenus Citrus. Owing to the complicated topography, the mountainous regions and the Yangtze River have provided long-term stable habitats for C. ichangensis and acted as main barriers for its expansion, which might facilitate the process of speciation. Statistical population models and genetic data indicated strong genetic structure in C. ichangensis, which might result from the restricted gene flow, genetic drift, and population bottlenecks.     

High genetic diversity in an endangered medicinal plant, <Emphasis Type="Italic">Saussurea involucrata</Emphasis> (<Emphasis Type="Italic">Saussurea</Emphasis>, Asteraceae), in western Tianshan Mountains,China

Saussurea involucrata (Asteraceae) is a medicinal and second-degree national priority endangered plant that is mainly distributed in the high latitude region of the western Tianshan Mountains. The population is fragmented and isolated, and extensive human impact merits a suitable and specific conservation strategy, which can be compiled based on the genetic diversity, population structure, and demographic history. Phylogeographic studies were conducted on a total of five natural populations and 150 individuals were sampled. Data from three cpDNA intergenic spacer regions (trnL-F, matK, and ndhF-rpl32) and nrDNA ITS sequences showed that twelve haplotypes in cpDNA and five haplotypes in nrDNA indicated high genetic diversity among populations sampled (H _T?=?0.820 and 0.756) and within populations sampled (H _S?=?0.792 and 0.721). Additionally, the high genetic diversity did not mirror genetic structure in either cpDNA (F _ST?=?0.03153, G _ST?>?N _ST, p?<?0.05) or nrDNA (F _ST?=?0.03666, meaningless G _ST and N _ST). Two groups (north and south) were determined for a SAMOVA analysis. Based on this analysis, the demographic history was conducted with a Bayesian Skyline Plot and Isolation with Migration analysis, which showed sustainable and stable extension without a marked bottleneck. Divergence time was indicated at c. 6.25 Mya (90%HPD: 15.30–0.22 Mya) in the Miocene, which is consistent with the formation of the Kelasu section of Tianshan. The southern populations in the Bayanbulak and Gonglu regions require additional attention and transplanting would be an effective way to restore rare cpDNA haplotypes, increase effective population size, and migration rate. Our results suggested that in situ conservation of S. involucrata in western Tianshan should be the main strategy for protection and recovery of the species.     

Recent low levels of differentiation in the native <Emphasis Type="Italic">Bombus ephippiatus</Emphasis> (Hymenoptera: Apidae) along two Neotropical mountain-ranges in Guatemala

Recent anthropogenic fragmentation has led to population differentiation threatening viability of many species, including species specialized on mountainous ecosystems. Bombus ephippiatus, a widespread species mostly found in mountains in the Neotropics, seems to use the highlands as island, and deforested lowland areas may represent barriers to their dispersal, leading to isolation and potentially loss of genetic diversity. Yet, lack of knowledge of its population structure does not allow adequate management and conservation. To fill this knowledge gap, we assessed the population structure and inferred dispersion of B. ephippiatus in two mountain-ranges in Guatemala (Volcanic Chain and Sierra de las Minas). This region is characterized by high topographic variation and considerable deforestation strain. We analyzed the effects of elevation and land-use on genetic differentiation of B. ephippiatus populations and inferred its demography in the region. Our results suggest that B. ephippiatus is able to disperse long distances across most landscape types, reflected by its high genetic diversity, high effective population size, considerable gene flow, low population differentiation, as well as the lack of isolation by distance. Hence, B. ephippiatus may be a resilient species for the provision of pollination services. However, we detected a subtle divergence of B. ephippiatus into two clusters, of which Sierra de las Minas has been identified as a regional hotspot of genetic and species endemism. Yet, differentiation is very recent and hence likely caused by lowland deforestation. The combined effects of current forest cover and elevation partially explain the observed subtle patterns of differentiation suggesting that the maintenance of suitable habitat is crucial to ensure population connectivity of this keystone pollinator.     

Genetic characterization of <Emphasis Type="Italic">Brycon hilarii</Emphasis> (Characiformes) populations within the Pantanal: Aspects of their conservation within a globally important neotropical wetland

Brycon hilarii, a characid species endemic to the Upper Paraguay hydrographic basin, is important to regional artisanal and sports fisheries. To develop effective strategies for conservation of this species in the face of potential environmental changes in the Pantanal region, we characterized genetic structuring within and among six B. hilarii collections based on variation at five microsatellite DNA markers. Within-population genetic variability was high, with 75 different alleles; mean average allelic richness per locus per sample location ranged from 6.06 to 7.99. Nei’s gene diversity (hs) varied among drainages from 0.66 (±0.2) to 0.69 (±0.2), with an average across the four genetically identified populations of 0.68 (±0.02). Analyses of Jost’s D _EST and F _ST-like indices, AMOVA, and Structure-based clustering analyses indicated that B. hilarii populations exhibit a low level of genetic structure, with some indications that the Taquari River population is somewhat distinct from others. Results of K-means analysis suggested little or no structuring, with weakly differentiated populations above and below the confluence of the Paraguay and Taquari rivers. Because B. hilarii populations in the Pantanal are linked by high levels of gene flow, habitat alterations that would interfere with gene flow may jeopardize the long-term persistance of the species.     

Modern State of Populations of Endemic <Emphasis Type="Italic">Oxytropis</Emphasis> Species from Baikal Siberia and Their Phylogenetic Relationships Based on Chloroplast DNA Markers

The genetic diversity and population structure of the endemic species of Baikal Siberia Oxytropis triphylla, O. bargusinensis, and O. interposita were studied for the first time on the basis of the nucleotide polymorphism of intergenic spacers psbA–trnH, trnL–trnF, and trnS–trnG of chloroplast DNA. All populations of these species were characterized by a high haplotype (0.762–0.924) and relatively low nucleotide (0.0011–0.0022) diversity. Analysis of the distribution of variability in O. triphylla and O. bargusinensis showed that there was no significant genetic differentiation between populations of each species; the gene flow was 4.43 and 8.91, respectively. The high level of genetic diversity in the studied populations indicates a relatively stable state of these populations. A study of the phylogenetic relationships of closely related species confirms the concept of the origin of O. bargusinensis and O. tompudae as a result of intersectional hybridization of the species of the sections Orobia and Verticillares.     

Phylogeographical structure inferred from cpDNA sequence variation of <Emphasis Type="Italic">Zygophyllum xanthoxylon</Emphasis> across north-west China

Zygophyllum xanthoxylon, a desert species, displaying a broad east–west continuous distribution pattern in arid Northwestern China, can be considered as a model species to investigate the biogeographical history of this region. We sequenced two chloroplast DNA spacers (psbK-psbI and rpl32-trnL) in 226 individuals from 31 populations to explore the phylogeographical structure. Median-joining network was constructed and analysis of AMOVA, SMOVA, neutrality tests and distribution analysis were used to examine genetic structure and potential range expansion. Using species distribution modeling, the geographical distribution of Z. xanthoxylon was modeled during the present and at the Last Glacial Maximum (LGM). Among 26 haplotypes, one was widely distributed, but most was restricted to either the eastern or western region. The populations with the highest levels of haplotype diversity were found in the Tianshan Mountains and its surroundings in the west, and the Helan Mountains and Alxa Plateau in the east. AMOVA and SAMOVA showed that over all populations, the species lacks phylogeographical structure, which is speculated to be the result of its specific biology. Neutrality tests and mismatch distribution analysis support past range expansions of the species. Comparing the current distribution to those cold and dry conditions in LGM, Z. xanthoxylon had a shrunken and more fragmented range during LGM. Based on the evidences from phylogeographical patterns, distribution of genetic variability, and paleodistribution modeling, Z. xanthoxylon is speculated most likely to have originated from the east and migrated westward via the Hexi Corridor.     

Genetic structure and diversity in relation to the recently reduced population size of the rare conifer, <Emphasis Type="Italic">Pseudotsuga japonica</Emphasis>, endemic to Japan

Rare species consisting of small populations are subject to random genetic drift, which reduces genetic diversity. Thus, determining the relationship between population size and genetic diversity would provide key information for planning a conservation strategy for rare species. We used six microsatellite markers to investigate seven extant populations of the rare conifer Pseudotsuga japonica, which is endemic to the Kii Peninsula and Shikoku Island regions that are geographically separated by the Kii Channel in southwest Japan. The population differentiation of P. japonica was relatively high (F_ST = 0.101) for a coniferous species, suggesting limited gene flow among populations. As expected, significant regional differentiation (AMOVA; p?<?0.05) indicated genetic divergence across the Kii Channel. A strong positive correlation between census population size and the number of rare alleles (r?=?0.862, p?<?0.05) was found, but correlations with major indices of genetic diversity were not significant (allelic richness: r?=?0.649, p?=?0.104, expected heterozygosity: r?=?0.361, p?=?0.426). The observed order of magnitude of correlation with three genetic diversity indices corresponded with the theoretically expected order of each index’ sensitivity (i.e., the rate of decline per generation) to the bottleneck event. Thus, features that exhibit a faster response, i.e., the number of rare alleles, would have been subject to deleterious effects of the recent decline in population size, which is presumably caused by the development of extensive artificial plantations of other tree species over the last several decades. Finally, we propose a conservation plan for P. japonica based on our findings.     

Genetic Diversity and Phylogenetic Relationships of Two Closely Related Northeast China <Emphasis Type="Italic">Vicia</Emphasis> Species Revealed with RAPD and ISSR Markers

RAPD and ISSR analyses revealed genetic diversity and relationships among 11 populations of two closely related northeast China Vicia species, Vicia ramuliflora and V. unijuga. Both methods yielded similar and complementary results, showing high genetic diversity. Vicia ramuliflora had 100% polymorphic loci in both RAPD and ISSR, and V. unijuga had 100% polymorphic loci for RAPD and 98.96% for ISSR. Genetic differentiation was moderate among populations of each species. Genetic variation was distributed mainly within populations for the two species. The high level of gene flow was important for the allocation of genetic variation. The UPGMA dendrogram and principal coordinates analysis at the level of individuals and populations showed that V. ramuliflora and V. unijuga were more closely related than either of them was to the outgroup species, V. cracca. The small molecular variance of V. ramuliflora and V. unijuga supports the conclusion that these two species had a common ancestor.     

Species delimitation and conservation genetics of the Canarian endemic <Emphasis Type="Italic">Bethencourtia</Emphasis> (Asteraceae)

Bethencourtia Choisy ex Link is an endemic genus of the Canary Islands and comprises three species. Bethencourtia hermosae and Bethencourtia rupicola are restricted to La Gomera, while Bethencourtia palmensis is present in Tenerife and La Palma. Despite the morphological differences previously found between the species, there are still taxonomic incongruities in the group, with evident consequences for its monitoring and conservation. The objectives of this study were to define the species differentiation, perform population genetic analysis and propose conservation strategies for Bethencourtia. To achieve these objectives, we characterized 10 polymorphic SSR markers. Eleven natural populations (276 individuals) were analyzed (three for B. hermosae, five for B. rupicola and three for B. palmensis). The results obtained by AMOVA, PCoA and Bayesian analysis on STRUCTURE confirmed the evidence of well-structured groups corresponding to the three species. At the intra-specific level, B. hermosae and B. rupicola did not show a clear population structure, while B. palmensis was aggregated according to island of origin. This is consistent with self-incompatibility in the group and high gene flow within species. Overall, the genetic diversity of the three species was low, with expected heterozygosity values of 0.302 (B. hermosae), 0.382 (B. rupicola) and 0.454 (B. palmensis). Recent bottleneck events and a low number of individuals per population are probably the causes of the low genetic diversity. We consider that they are naturally rare species associated with specific habitats. The results given in this article will provide useful information to assist in conservation genetics programs for this endemic genus.     

Limited diversity associated with duplicated class II MHC-<Emphasis Type="Italic">DRB</Emphasis> genes in the red squirrel population in the United Kingdom compared with continental Europe

The red squirrel (Sciurus vulgaris) population in the United Kingdom has declined over the last century and is now on the UK endangered species list. This is the result of competition from the eastern grey squirrel (S. carolinensis) which was introduced in the 19th century. However, recent evidence suggests that the rate of population decline is enhanced by squirrelpox disease, caused by a viral infection carried asymptomatically by grey squirrels but to which red squirrels are highly susceptible. Population genetic diversity provides some resilience to rapidly evolving or exotic pathogens. There is currently no data on genetic diversity of extant UK squirrel populations with respect to genes involved in disease resistance. Diversity is highest at loci involved in the immune response including genes clustered within the major histocompatibility complex (MHC). Using the class II DRB locus as a marker for diversity across the MHC region we genotyped 110 red squirrels from locations in the UK and continental Europe. Twenty-four Scvu-DRB alleles at two functional loci; Scvu-DRB1 and Scvu-DRB2, were identified. High levels of diversity were identified at both loci in the continental populations. In contrast, no diversity was observed at the Scvu-DRB2 locus in the mainland UK population while a high level of homozygosity was observed at the Scvu-DRB1 locus. The red squirrel population in the UK appears to lack the extensive MHC diversity associated with continental populations, a feature which may have contributed to their rapid decline.     

Correlations between the ages of<Emphasis Type="Italic">Alnus</Emphasis> host species and the genetic diversity of associated endosymbiotic<Emphasis Type="Italic">Frankia</Emphasis> strains from nodules

Nodule samples were collected from four alder species:Alnus nepalensis, A. sibirica, A. tinctoria andA. mandshurica growing in different environments on Gaoligong Mountains, Yunnan Province of Southwest China and on Changbai Mountains, Jilin Province of Northeast China. PCR-RFLP analysis of the IGS betweennifD andnifK genes was directly applied to unculturedFrankia strains in the nodules. A total of 21 restriction patterns were obtained. TheFrankia population in the nodules ofA. nepalensis had the highest genetic diversity among all fourFrankia populations; by contrast, the population in the nodules ofA. mandshurica had the lowest degree of divergence; the ones in the nodules ofA. sibirica andA. tinctoria were intermediate. A dendrogram, which was constructed based on the genetic distance between the restriction patterns, indicated thatFrankia strains fromA. sibirica andA. tinctoria had a close genetic relationship.Frankia strains fromA. nepalensis might be the ancestor ofFrankia strains infecting otherAlnus species. From these results and the inference of the ages ofAlnus host species, it is deduced that there was a co-evolution betweenAlnus and its microsymbiontFrankia in China.     

Genetic diversity and population structure of common walnut (<Emphasis Type="Italic">Juglans regia</Emphasis>) in China based on EST-SSRs and the nuclear gene phenylalanine ammonia-lyase (<Emphasis Type="Italic">PAL</Emphasis>)

Common walnut (Juglans regia L.) is an economically important temperate tree species valued for both its nut and wood. We investigated the genetic diversity and population structure of J. regia germplasm from 13 locations in China using 10 markers derived from expressed sequences (EST-SSR) and sequence polymorphisms within the phenylalanine ammonia-lyase (PAL) gene. Analysis of the population genetic structure based on EST-SSRs showed distinct populations in northern versus southern China that were not reflected in the spatial distribution of PAL haplotypes. High levels of population differentiation were probably the result of reproductive isolation and in southern China, hybridization with Juglans sigillata. The results indicate the possible presence of distinct evolutionary lineages of J. regia in the Qinling and Daba Mountains of China and in Yunnan province that may require ecological management if they are to be retained as in situ resources.     

The contrasting genetic patterns of two sympatric flying fox species from the Comoros and the implications for conservation

Pteropus livingstonii and Pteropus seychellensis comorensis are endemic fruit bat species that are among the most threatened animals in the Comoros archipelago. Both species are pollinators and seed dispersers of native and cultivated plants and are thus of crucial importance for the regeneration of natural forests as well as for cultivated plantations. However, these species are subject to strong anthropogenic pressures and face one of the highest rates of natural habitat loss reported worldwide. Yet little is known about the population genetic structure of these two species, making it difficult to define relevant conservation strategies. In this study, we investigated for the two flying fox species (1) the level of genetic diversity within islands, as well as across the archipelago and (2) the genetic structure between the two islands (Anjouan and Mohéli) for P. livingstonii and between the four islands of the archipelago (Anjouan, Mohéli, Grande Comore and Mayotte) for P. s. comorensis using mitochondrial and microsatellite markers. The results revealed contrasting patterns of genetic structure, with P. s. comorensis showing low genetic structure between islands, whereas P. livingstonii exhibited high levels of inter-island genetic differentiation. Overall, the genetic analyses showed low genetic diversity for both species. These contrasting genetic patterns may be the result of different dispersal patterns and the populations’ evolutionary histories. Our findings lead us to suggest that in terms of conservation strategy, the two populations of P. livingstonii (on Anjouan and Mohéli islands) should be considered as two separate management units. We recommend focusing conservation efforts on the Anjouan population, which is the largest, exhibits the highest genetic diversity, and suffers the greatest anthropogenic pressure. As for P. s. comorensis, its four populations could be considered as a single unit for conservation management purposes. For this species, we recommend protecting roosting trees to reduce population disturbance.     

Non-native plants affect generalist pollinator diet overlap and foraging behavior indirectly,via impacts on native plant abundance

Flowering invasive plants can have dramatic effects on the resource landscape available to pollinators. Because many pollinators exhibit behavioral plasticity in response to competitor or resource density, this in turn can result in impacts on ecological processes such as pollination and plant reproduction. We examine how interactions between five common generalist eusocial bees change across an invasion gradient by examining how bee abundance and diet overlap changed with variation in both invasive plant abundance and competitor abundance in a temperate oak-savannah ecosystem. Specifically we focus on the bumblebees Bombus bifarius, B. mixtus, B. melanopygus and B. vosnesenskii, as well as the non-native honeybee Apis mellifera, and their interactions with the native flowering plants Camassia quamash, Camassia liechtlinii, and the invasive shrub Cytisus scoparius. We further examine whether changes in pollinator visits to the invasive and two common native plants can explain changes in diet overlap. Abundance of the invasive plant and other common floral resources had strong impacts on focal bee abundance, with certain species more likely to be present at highly invaded sites. This may be because highly invaded sites tended to be embedded in forested landscapes where those bees are common. Diet overlap was most affected by abundance of a common native plant, rather than the invasive plant, with diet overlap increasing non-linearly with abundance of the native plant. Furthermore, Apis mellifera, did not appear to have direct competitive effects on native bumblebees in this habitat. However, visit patterns suggest that bees most abundant at highly invaded sites may compete for access to native resources. Thus the impacts of this invasive plant on our focal bee species may be primarily indirect, via its’ competitive effects on native plants.     

Genetic diversity and population structure of the roughskin sculpin (<Emphasis Type="Italic">Trachidermus fasciatus</Emphasis> Heckel) inferred from microsatellite analyses: implications for its conservation and management

Identification of population units is crucial for management and monitoring programs, especially for endangered wild species. The roughskin sculpin (Trachidermus fasciatus Heckel) is a small catadromous fish and has been listed as a second class state protected aquatic animal since 1988 in China. To achieve sustainable conservation of this species, it is necessary to clarify the existing genetic structure both between and within populations. Here, population genetic structure among eight populations of T. fasciatus were analyzed by using 16 highly polymorphic microsatellites. High levels of genetic variation were observed in all populations. All pairwise F _ST estimates were significant after false discovery rate correction (overall average F _ST = 0.054). Furthermore, both STRUCTURE and discriminant analysis of principal components (DAPC) analysis showed that the eight populations were grouped into six clusters. BAYESASS analysis showed generally low recent and asymmetric migration among populations. All these results suggested significant genetic structure across populations. However, there was no isolation by distance relationship among populations, likely resulting from barriers to gene flow created by habitat fragmentation. Our results highlight the need for in situ conservation efforts for T. fasciatus across its entire distribution range, through maximizing habitat size and quality to preserve overall genetic diversity and evolutionary potential.     

Meta-analysis reveals asymmetric reduction in the genetic diversity of introduced populations of exotic insects

Factors promoting the invasion success of introduced populations have been receiving increased attention in studies of biological invasions. Previous reports have indicated that successful invasions may be attributable to reduced genetic diversity in the invasive species. However, there is large variation in the magnitude and direction of the impact of exotic species that have remained unexplained. Here, we present a structured meta-analysis of papers investigating the genetic diversity of native and introduced populations of exotic insects using nuclear microsatellites and mitochondrial DNA sequences. The results indicate that invasion by exotic insects had an overall reducing effect on the genetic diversity of the invading population, with nonzero effect sizes for the number of alleles (NA), observed heterozygosity (Ho), expected heterozygosity (He) and nucleotide diversity (Nd). However, when analyzing different orders (e.g., Lepidoptera, Hemiptera), the effect sizes of NA, Ho and Nd in Lepidoptera were found to bracket zero, as did the effect size of He in Hemiptera. These results suggest an asymmetric reduction in the genetic diversity of introduced populations of exotic insects, indicating diverse mechanisms underlying their successful invasion.     

Co-occurring patterns of endophyte infection and genetic structure in the alpine grass, <Emphasis Type="Italic">Festuca eskia</Emphasis>: implications for seed sourcing in ecological restoration

Choosing the provenance of seed used in ecological restoration could entail its success. An alternative approach to examine local adaptation in seed sourcing is the assessment of genetic structure and diversity based on molecular markers. These types of analyses focus on the genetics of the target plant itself and eliminate the genetic influence of associated organisms, such as Epichloë/Neotyphodium endophytes in grasses. By impacting the fitness of their host, such symbionts may influence population genetic structure and diversity. Therefore, seed sourcing for grasses must consider the influence of their endophytes to increase seed translocation success and minimize the risks associated with this practice. To delineate seed zones for restoration of the alpine fescue Festuca eskia Ramond ex. DC. (Poaceae), we assessed population genetic differentiation and diversity patterns in the species including endophyte occurrence along altitudinal and longitudinal gradients in the Pyrenees Mountains. Twenty-three populations were analysed for endophyte status, and three STS and one SSR marker were used to examine genetic differentiation and diversity patterns. Results showed that F. eskia hosts an asexual form of Epichloë and infection frequency within populations decreased from East to West (100 vs. 8–25%). Molecular markers separated F. eskia into two East and West groups, and endophyte infection and genetic patterns were congruent with molecular data. Little evidence for genetic differentiation or difference in endophyte occurrence associated with altitude was detected. Little variation was found in within population diversity, regardless of provenance altitude and site, and/or endophyte infection frequency. The results of this study suggested the establishment of two distinct management units for F. eskia seed sourcing restoration.