Looking back to go forward: genetics informs future management of captive and reintroduced populations of the black-footed rock-wallaby <Emphasis Type="Italic">Petrogale lateralis</Emphasis>

Active management is essential to the survival of many threatened species globally. Captive breeding programmes can play an important role in facilitating the supplementation, translocation and reintroduction of wild populations. However, understanding the genetic dynamics within and among wild and captive populations is crucial to the planning and implementation of ex situ management, as adaptive potential is, in part, driven by genetic diversity. Here, we use 14 microsatellite loci and mitochondrial Control Region sequence to examine the population genetics of both wild populations and captive colonies of the endangered warru (the MacDonnell Ranges race of the black-footed rock-wallaby Petrogale lateralis) in central Australia, to understand how historical evolutionary processes have shaped current diversity and ensure effective ex situ management. Whilst microsatellite data reveal significant contemporary differentiation amongst remnant warru populations, evidence of contemporary dispersal and relatively weak isolation by distance, as well as a lack of phylogeographic structure suggests historical connectivity. Genetic diversity within current captive populations is lower than in the wild source populations. Based on our genetic data and ecological observations, we predict outbreeding depression is unlikely and hence make the recommendation that captive populations be managed as one genetic group. This will increase genetic diversity within the captive population and as a result increase the adaptive potential of reintroduced populations. We also identify a new site in the Musgrave Ranges which contains unique alleles but also connectivity with a population 6 km away. This novel genetic diversity could be used as a future source for supplementation.     

Exploring the legacy of African and Indigenous Caribbean admixture in Puerto Rico

Objectives

From an anthropological genetic perspective, little is known about the ethnogenesis of African descendants in Puerto Rico. Furthermore, historical interactions between Indigenous Caribbean and African descendant peoples that may be reflected in the ancestry of contemporary populations are understudied. Given this dearth of genetic research and the precedence for Afro-Indigenous interactions documented by historical, archeological, and other lines of evidence, we sought to assess the biogeographic origins of African descendant Puerto Ricans and to query the potential for Indigenous ancestry within this community.

Materials and Methods

Saliva samples were collected from 58 self-identified African descendant Puerto Ricans residing in Puerto Rico. We sequenced whole mitochondrial genomes and genotyped Y chromosome haplogroups for each male individual (n = 25). Summary statistics, comparative analyses, and network analysis were used to assess diversity and variation in haplogroup distribution between the sample and comparative populations.

Results

As indicated by mitochondrial haplogroups, 66% had African, 5% had European, and 29% had Indigenous American matrilines. Along the Y chromosome, 52% had African, 28% had Western European, 16% had Eurasian, and, notably, 4% had Indigenous American patrilines. Both mitochondrial and Y chromosome haplogroup frequencies were significantly different from several comparative populations.

Discussion

Biogeographic origins are consistent with historical accounts of African, Indigenous American, and European ancestry. However, this first report of Indigenous American paternal ancestry in Puerto Rico suggests distinctive features within African descendant communities on the island. Future studies expanding sampling and incorporating higher resolution genetic markers are necessary to more fully understand African descendant history in Puerto Rico.     

Strong founder effects and low genetic diversity in introduced populations of Coqui frogs

The success of non-native species may depend on the genetic resources maintained through the invasion process. The Coqui ( Eleutherodactylus coqui ), a frog endemic to Puerto Rico, was introduced to Hawaii in the late 1980s via the horticulture trade, and has become an aggressive invader. To explore whether genetic diversity and population structure changed with the introduction, we assessed individuals from 15 populations across the Hawaiian Islands and 13 populations across Puerto Rico using six to nine polymorphic microsatellite loci and five dorsolateral colour patterns. Allelic richness ( R _T) and gene diversity were significantly higher in Puerto Rico than in Hawaii populations. Hawaii also had fewer colour patterns (two versus three to five per population) than Puerto Rico. We found no isolation by distance in the introduced range, even though it exists in the native range. Results suggest extensive mixing among frog populations across Hawaii, and that their spread has been facilitated by humans. Like previous research, our results suggest that Hawaiian Coquis were founded by individuals from sites around San Juan, but unlike previous research the colour pattern and molecular genetic data (nuclear and mtDNA) support two separate introductions, one on the island of Hawaii and one on Maui. Coquis are successful invaders in Hawaii despite the loss of genetic variation. Future introductions may increase genetic variation and potentially its range.     

Genetic assessment of <Emphasis Type="Italic">Abies koreana</Emphasis> (Pinaceae), the endangered Korean fir,and conservation implications

To establish a management plan for endangered and rare species, genetic assessment must first be conducted. The genetic characteristics of plant species are affected by demographic history, reproductive strategy, and distributional range as well as anthropological effects. Abies koreana E. H. Wilson (Pinaceae), Korean fir, is endemic to Korea and found only in sub-alpine areas of the southern Korean Peninsula and Jejudo Island. This species has been designated as critically endangered by the International Union for Conservation of Nature due to a continuous decline in its range and population fragmentation. We genotyped 176 individuals from seven natural populations and two afforested populations on the Korean Peninsula using 19 microsatellite loci. STRUCTURE analysis revealed two genetic clusters in natural populations (F _st  = 0.040 and R _st  = 0.040) despite low differentiation. We did not detect a significant reduction in genetic diversity or the signature of a genetic bottleneck despite population fragmentation and small population size. We deduced that this species exhibits a metapopulation structure, with the population on Jirisan Mountain acting as a source of genetic diversity for other local small populations on the Korean Peninsula, through contemporary asymmetric gene flow. However, the majority of afforested individuals on the Korean Peninsula originated from a different gene cluster. Thus, we recommend a conservation strategy that maintains two genetically unique clusters.     

Demographic history and genetic diversity in West Indian Coereba flaveola populations

The bananaquit (Coereba flaveola) has been well studied throughout the Caribbean region from a phylogenetic perspective. However, data concerning the population genetics and long-term demography of this bird species are lacking. In this study, we focused on three populations within the Lesser Antilles and one on Puerto Rico and assessed genetic and demographic processes, using five nuclear and two mitochondrial markers. We found that genetic diversity of bananaquits on Puerto Rico exceeds that on the smaller islands (Dominica, Guadeloupe and Grenada); this might reflect either successive founder events from Puerto Rico to Grenada, or more rapid drift in smaller populations subsequent to colonization. Population growth rate estimates showed no evidence of rapid expansion and migration was indicated only between populations from the closest islands of Dominica and Guadeloupe. Overall, our results suggest that a "demographic fission" model, considering only mutation and drift, but without migration, can be applied to these bananaquit populations in the West Indies.     

Genetic evidence of fragmented populations and inbreeding in the Colombian endemic Dahl’s toad-headed turtle (<Emphasis Type="Italic">Mesoclemmys dahli</Emphasis>)

Population fragmentation is one of the most concerning consequences of habitat fragmentation, as small and isolated populations suffer increased genetic drift and inbreeding. However, the extent to which habitat fragmentation leads to population fragmentation depends not only on the landscape structure, but also on the response of organisms to it. This behavioral component makes it difficult to detect population fragmentation even if the habitat is fragmented, unless appropriate tools are used. In this study, we used a molecular approach to evaluate if Dahl’s toad-headed turtle (Mesoclemmys dahli) population was fragmented, given that it occurs in a very restricted area within the most degraded biome of Colombia, the tropical dry forest. We developed a panel of 15 microsatellite loci in order to perform the first genetic assessment of M. dahli across its complete geographic range. We found that M. dahli has significant genetic structure with at least four subpopulations, with surprisingly moderate to high levels of genetic diversity. Despite high levels of genetic diversity, subpopulations are very small (effective population sizes?<?50) and isolated, with little to no contemporary gene flow among them. As a consequence, mating among related individuals has been occurring, and all four populations are showing high degrees of inbreeding. To counteract this threat, we recommend an urgent genetic rescue strategy accompanied by habitat restoration, and advocate for a new conservation status assessment, not based on geographic range, but on adult population size and level of fragmentation.     

Genetic diversity and population structure of the northern snakehead (<Emphasis Type="Italic">Channa argus</Emphasis> Channidae: Teleostei) in central China: implications for conservation and management

Major threats to freshwater fish diversity now include loss of native genetic diversity as a consequence of translocations of fishes between sites and from hatcheries to sites, and small effective population sizes resulting from overfishing and/or habitat loss. Ten polymorphic microsatellite markers were employed to evaluate genetic diversity, population genetic structure and gene flow amongst nine populations of the ecologically and economically important fish, the northern snakehead (Channa argus), in three river systems in central China. Multiple analyses revealed evidence of high genetic diversity and pronounced subdivision based on both regional separation and on river systems. A lack of evidence of genetic bottleneck over recent generations was consistent with the long-term stability of population size and contemporary distribution. The effective population sizes for most C. argus populations were small, suggesting the need for future conservation efforts focusing on these populations. Different lines of evidence point to the local enhancement of stocks by both aquaculture-reared fish and the transfer of wild fish. This study illustrates how human activities may affect genetic diversity and population genetic structure of C. argus populations, and highlights the need for new management regimes to protect native freshwater fish genetic diversity.     

Hierarchical metapopulation structure in a highly mobile marine predator: the southern Australian coastal bottlenose dolphin (<Emphasis Type="Italic">Tursiops</Emphasis> cf. <Emphasis Type="Italic">australis</Emphasis>)

Little is known about the population ecology of the recently described bottlenose dolphin species Tursiops australis. The classification of this species is still under debate, but this putative species is thought to be comprised of small and genetically distinct populations (including sub-populations under increasing anthropogenic threats) and is likely endemic to coastal southern Australia. Mitochondrial DNA (mtDNA) control region sequences and microsatellite loci were used to assess genetic variation and hierarchical population structure of coastal T. cf. australis across a range of spatial scales and environmental discontinuities between southern Western Australia (WA) and central South Australia (SA). Overall, genetic diversity was similar to that typically found for bottlenose dolphins, although very low mtDNA diversity was found in Gulf St. Vincent (GSV) dolphins. We found historical genetic subdivision and likely differences in colonisation between GSV and Spencer Gulf, outer- and inner-gulf locations, and SA/WA and previously identified Victorian/Tasmanian populations. A hierarchical metapopulation structure was revealed along southern Australia, with at least six genetic populations occurring between Esperance, WA and southern Tasmania. In addition, fine-scale genetic subdivision was observed within each SA/WA population. In general, contemporary migration was limited throughout southern Australia, but an important gene flow pathway was identified eastward along the Great Australian Bight. Management strategies that promote gene flow among populations should be implemented to assist with the maintenance of the inferred metapopulation structure. Further research into the population ecology of this species is needed to facilitate well-informed management decisions.     

Conservation genetics of redside dace (<Emphasis Type="Italic">Clinostomus elongatus</Emphasis>): phylogeography and contemporary spatial structure

Redside dace Clinostomus elongatus (Teleostei: Cyprinidae) is a species of conservation concern that is declining throughout its range as a result of habitat fragmentation, degradation and loss. We characterized the genetic structure and diversity of redside dace populations across the species range using mitochondrial and microsatellite data to inform conservation efforts and assess how historical and recent events have shaped genetic structure and diversity within and among populations. Phylogeographic structure among 28 redside dace populations throughout southern Ontario (Canada) and the United States was assessed by sequence analysis of the mitochondrial cytochrome b and ATPase 6 and 8 genes. Populations were also genotyped using ten microsatellite loci to examine genetic diversity within and among populations as well as contemporary spatial structuring. Mitochondrial DNA sequence data revealed three geographically distinct lineages, which were highly concordant with groupings identified by microsatellite analysis. The combined genetic data refute published glacial refugia hypotheses of a single Mississippian refugium or of two lineages associated with Mississippian and Atlantic refugia. Secondary contact between the two eastern groups was documented in the Allegheny River drainage and tributaries to Lake Ontario. With the exception of several allopatric populations within the Allegheny watershed, high genetic structuring among populations suggests their isolation, indicating that recovery efforts should be population-based.     

Genetic evidence of range-wide population declines in an Australian marsupial prior to European settlement

Reconstruction of a species demographic history can be used to investigate impacts of environmental change through time. Australia’s mesic biome experienced massive changes during the Holocene, including climate fluctuations, increased human populations, and European settlement. Using microsatellite data from 202 brush-tailed rock-wallabies (Petrogale penicillata) sampled across the species current geographic range, we investigated gene flow and inferred the demographic history of the species to explore the historical impacts of environmental change on this once wide-ranging marsupial mammal. We found high levels of genetic diversity in all colonies, despite very restricted contemporary gene flow and no sign of historical gene flow. Demographic analyses showed that individual populations have low effective population sizes (N _e?<?200). We identified a major historical decline throughout the species range occurring 10,000–1000 years before present, spanning a period with increased El Niño Southern Oscillation activity, increased human population size and establishment of the dingo population. This major decline pre-dates the European settlement of Australia and so places the species most recent dramatic decline into context, suggesting that brushed-tailed rock-wallabies were inherently vulnerable to major changes to their environment.     

Climate as a driver of tropical insular diversity: comparative phylogeography of two ecologically distinctive frogs in Puerto Rico

The effects of late Quaternary climate on distributions and evolutionary dynamics of insular species are poorly understood in most tropical archipelagoes. We used ecological niche models under past and current climate to derive hypotheses regarding how stable climatic conditions shaped genetic diversity in two ecologically distinctive frogs in Puerto Rico. Whereas the mountain coquí Eleutherodactylus portoricensis is restricted to montane forest in the Cayey and Luquillo Mountains, the red‐eyed coquí E. antillensis is a habitat generalist distributed across the entire Puerto Rican Bank (Puerto Rico and the Virgin Islands, excluding St Croix). To test our hypotheses, we conducted phylogeographic and population genetic analyses based on mitochondrial and nuclear loci of each species across their range in Puerto Rico. Patterns of population differentiation in E. portoricensis, but not in E. antillensis, supported our hypotheses. For E. portoricensis, these patterns include: individuals isolated by long‐term unsuitable climate in the Río Grande de Loíza Basin in eastern Puerto Rico belong to different genetic clusters; past and current climate strongly predicted genetic differentiation; and Cayey and Luquillo Mountains populations split prior to the last interglacial. For E. antillensis, these patterns include: genetic clusters did not fully correspond to predicted long‐term unsuitable climate; and past and current climate weakly predicted patterns of genetic differentiation. Genetic signatures in E. antillensis are consistent with a recent range expansion into western Puerto Rico, possibly resulting from climate change and anthropogenic influences. As predicted, regions with a large area of long‐term suitable climate were associated with higher genetic diversity in both species, suggesting larger and more stable populations. Finally, we discussed the implications of our findings for developing evidence‐based management decisions for E. portoricensis, a taxon of special concern. Our findings illustrate the role of persistent suitable climatic conditions in promoting the persistence and diversification of tropical island organisms.     

Colonization history and population differentiation of the Honey Bees (Apis mellifera L.) in Puerto Rico

Honey bees (Apis mellifera L.) are the primary commercial pollinators across the world. The subspecies A. m. scutellata originated in Africa and was introduced to the Americas in 1956. For the last 60 years, it hybridized successfully with European subspecies, previous residents in the area. The result of this hybridization was called Africanized honey bee (AHB). AHB has spread since then, arriving to Puerto Rico (PR) in 1994. The honey bee population on the island acquired a mosaic of features from AHB or the European honey bee (EHB). AHB in Puerto Rico shows a major distinctive characteristic, docile behavior, and is called gentle Africanized honey bees (gAHB). We used 917 SNPs to examine the population structure, genetic differentiation, origin, and history of range expansion and colonization of gAHB in PR. We compared gAHB to populations that span the current distribution of A. mellifera worldwide. The gAHB population is shown to be a single population that differs genetically from the examined populations of AHB. Texas and PR groups are the closest genetically. Our results support the hypothesis that the Texas AHB population is the source of gAHB in Puerto Rico.     

Genetic diversity from pre-bottleneck to recovery in two sympatric pinniped species in the Northwest Atlantic

Conservation successes of the past several decades provide natural settings to study post-bottleneck evolutionary processes in species undergoing recovery. Here, we study the impact of demographic change on genetic diversity in parallel natural experiments of historical decline and subsequent recovery in two sympatric pinniped species in the Northwest Atlantic, the gray seal (Halichoerus grypus atlantica) and harbor seal (Phoca vitulina concolor). We compare genetic diversity at the mitochondrial control region today to diversity in archaeological specimens, which represent the populations prior to the regional bounties of the late 1800s to mid-1900s that drastically reduced population sizes and led to local extirpations. We further assess genetic diversity throughout recovery, using biological collections from ongoing long-term studies of both species. Overall, the genetic data are consistent with the historical presence of large, genetically diverse populations of pinnipeds prior to human exploitation, and suggest that gray seals were more dramatically impacted by historical bottlenecks than harbor seals in the Northwest Atlantic. Current mitochondrial diversity in both species is relatively high, and we observe little change over the past several decades during a period of roughly parallel rapid population increases. However, there remain large differences in haplotype composition between pinniped populations of pre-exploitation and today, a lasting genetic signature of historical exploitation that is likely to persist into the future.     

Effects of invasive Green Iguanas (<Emphasis Type="Italic">Iguana iguana</Emphasis>) on seed germination and seed dispersal potential in southeastern Puerto Rico

Green Iguanas (Iguana iguana) are invasive in Puerto Rico due to a variety of negative economic effects, yet we know very little about their ecological impacts. Because they are herbivorous, defecate intact seeds, move through the forest, and have long gut-passage times, Green Iguanas may affect seed germination and seed dispersal. In summer 2013, a total of 258 Green Iguana scat samples were collected at the Humacao Natural Reserve in southeastern Puerto Rico. Seeds extracted from scat and collected from fruit were planted under common garden conditions using experimental treatments designed to tease apart the effects of feces, fruit, and ingestion on seed germination. Green Iguanas decreased the time for seeds to germinate in Ficus spp. by removing fruit pulp, but had no effect on germination of native Annona glabra seeds. For non-native P. pterocarpus and Pterocarpus spp., Green Iguanas produced conflicting results, decreasing the percentage of seeds germinating, but at the same time, reducing the time for seeds to germinate. Green Iguanas likely disperse most seeds beyond the canopies of parental tree at our site. Government and economic resources are being used to eradicate Green Iguana populations in Puerto Rico, but the lack of consistent effects of Green Iguanas on seed germination for the plant species consumed at our site complicates generalizing about their ecological effects and developing management plans that minimize negative effects for native plant communities. We recommend additional studies that target both species of particular concern, such as threatened native or invasive species, as well as studies of sensitive habitats in Puerto Rico.     

History shaped the geographic distribution of genomic admixture on the island of Puerto Rico

Contemporary genetic variation among Latin Americans human groups reflects population migrations shaped by complex historical, social and economic factors. Consequently, admixture patterns may vary by geographic regions ranging from countries to neighborhoods. We examined the geographic variation of admixture across the island of Puerto Rico and the degree to which it could be explained by historic and social events. We analyzed a census-based sample of 642 Puerto Rican individuals that were genotyped for 93 ancestry informative markers (AIMs) to estimate African, European and Native American ancestry. Socioeconomic status (SES) data and geographic location were obtained for each individual. There was significant geographic variation of ancestry across the island. In particular, African ancestry demonstrated a decreasing East to West gradient that was partially explained by historical factors linked to the colonial sugar plantation system. SES also demonstrated a parallel decreasing cline from East to West. However, at a local level, SES and African ancestry were negatively correlated. European ancestry was strongly negatively correlated with African ancestry and therefore showed patterns complementary to African ancestry. By contrast, Native American ancestry showed little variation across the island and across individuals and appears to have played little social role historically. The observed geographic distributions of SES and genetic variation relate to historical social events and mating patterns, and have substantial implications for the design of studies in the recently admixed Puerto Rican population. More generally, our results demonstrate the importance of incorporating social and geographic data with genetics when studying contemporary admixed populations.     

Assessing genetic structure in a rare clonal eucalypt as a basis for augmentation and introduction translocations

Genetics can provide information that is critical for planning translocations for conservation, such as levels of diversity and divergence of target and source populations. For clonal plants, assessing population characteristics (size, diversity, mortality, gene flow) that influence conservation values also requires identification of different genetic individuals. We used 12 microsatellite markers to guide germplasm source recommendations for augmentation and introduction translocations to conserve the critically endangered Eucalyptus cuprea that occurs in fragmented populations in the semi-arid shrublands of Western Australia. Ramet clumps with identical multilocus genotypes were identified in all populations but clonal richness (R = 0 ? 0.86) and heterogeneity (D = 0 ? 0.98) varied among populations. Genetic diversity was low to moderate in all populations (mean H _o = 0.61, mean A = 3.78) and did not differ significantly between localities. There was evidence of inbreeding in some populations but outcrossing (t _m = 0.495) in the small number of families available for study (N = 4) and genotypic diversity of the larger extant populations suggest the generation of novel genotypes is a component of the reproductive strategy. Most diversity was within populations and differentiation among populations was moderate (F _ST = 0.100) suggesting mixing of source population for translocation is unlikely to lead to outbreeding depression. Principal Co-ordinate and Bayesian analyses indicated the Northern population is distinct from Central/Southern populations. We recommend use of mixed germplasm to conserve the moderate diversity characterising larger remnant populations and to enable the production of recombinants through sexual reproduction. But given seed availability and the distinction of the Northern population, an initial precautionary approach to a translocation proposed for south of the geographical range may be to source germplasm from the Central/Southern locality.     

Dispersal, recruitment and migratory behaviour in a hawksbill sea turtle aggregation

We investigated the dispersal, recruitment and migratory behaviour of the hawksbill sea turtle ( Eretmochelys imbricata ), among different life-history stages and demographic segments of the large hawksbill turtle aggregation at Mona Island, Puerto Rico. There were significant differences in both mitochondrial DNA (mtDNA) haplotype diversity and haplotype frequencies among the adult males, females and juveniles examined, but little evidence for temporal heterogeneity within these same groups sampled across years. Consistent with previous studies and the hypothesis of strong natal homing, there were striking mtDNA haplotype differences between nesting females on Mona Island and nesting females in other major Caribbean rookeries. Breeding males also showed strong, albeit weaker, genetic evidence of natal homing. Overall, Bayesian mixed-stock analysis suggests that Mona Island was the natal rookery for 79% (65–94%) of males in the aggregation. In contrast, the Mona Island rookery accounted for only a small subset of the new juvenile recruits to the foraging grounds or in the population of older juvenile hawksbills turtles on Mona. Instead, both new recruits and the older juvenile hawksbill turtles on Mona more likely recruited from other Caribbean rookeries, suggesting that a mechanism besides natal homing must be influencing recruitment to feeding habitats. The difference in the apparent degree of natal homing behaviour among the different life-history stages of hawksbill turtles at Mona Island underscores the complexity of the species' life-history dynamics and highlights the need for both local and regional conservation efforts.     

Genetic diversity of a hitchhiker and prized food source in the Anthropocene: the Asian green mussel <Emphasis Type="Italic">Perna viridis</Emphasis> (Mollusca,Mytilidae)

Insight into a species’ native and introduced range is essential in understanding the invasion process. Genetic diversity, propagule pressure and environmental conditions all have been recognised as playing a determinant role in invasion success. Here, we aimed to investigate the genetic diversity and population genetic structure (using the COI mtDNA gene region and 22 nDNA microsatellite markers) of the Asian green mussel Perna viridis within its potential native range in Asia and at introduced locations in the USA and the Caribbean. We also analyse genetic data from vessel intercepts and an incursion. By doing so, we aimed to identify genetic signatures that could allow to track vessel samples to their source and provide further insight into potential high-risk invasive populations or areas. Three top hierarchical clusters were identified using the individual-based Bayesian clustering method in STRUCTURE, corresponding to populations in three world regions: (1) USA and Caribbean, (2) India and (3) Southeast Asia. Within Southeast Asia, additional analysis indicate a shallow genetic differentiation of three subgroups consisting of (3a) Thailand, (3b) Taiwan and Hong-Kong, and (3c) a cluster of Singapore–Indonesia samples. Overall, the population structure found in this study suggests that the markers used could be useful in identifying source populations, particularly between the three mains world regions. Most surprisingly however, this study shows that the genetic diversity of samples collected from vessel intercepts and incursions did not differ significantly from established populations in Southeast Asia. In this region, in addition to the high vessel connectivity and number of P. viridis transported, all sampled populations are likely to pose a comparable risk in terms of genetic diversity. The present work represents the most comprehensive population genetic study of P. viridis, and the first to address the potential genetic introduction risk posed by populations of this species. The information and genetic markers in this study constitute a valuable addition to the tools already used to infer on potential high-risk source populations of P. viridis. They should therefore prove useful for biosecurity surveillance and management actions directed at this species.     

New microsatellite markers for the ectomycorrhizal fungus Pisolithus tinctorius sensu stricto reveal the genetic structure of US and Puerto Rican populations

The ectomycorrhizal fungus Pisolithus tinctorius has been introduced to many areas around the world as a source of inoculum for pine plantations. However, little is known about the genetic structure of fungal populations in their introduced habitats. To study the genetics of exotic P. tinctorius populations, we developed and employed seven new microsatellite markers and compared samples from Puerto Rico (exotic range) and the eastern United States (native range). Bayesian cluster analysis, neighbor joining analysis and F_ST values all strongly separated Puerto Rican populations from North American populations. Consistent with a founder effect, populations from Puerto Rico had reduced allelic richness when compared to samples from the United States. The genetic structure of P. tinctorius populations in Puerto Rico is weak to modest and is not correlated with geographic distance reflecting anthropogenic movement of inoculum with forestry practices.