Spatial genetic variation and habitat association of <Emphasis Type="Italic">Rhinichthys cataractae</Emphasis>, the longnose dace,in the Driftless Area of the upper Mississippi River basin

The Driftless Area of the upper Mississippi River drainage is a unique geographic region because of its complex geological history and the influence of recent, intensive human activities. The longnose dace, Rhinichthys cataractae, is a relatively common, small freshwater fish that is distributed in swift, cool streams within the region. The aim of this study was to determine the spatial genetic differentiation of the longnose dace and define the broad scale environmental variables that shape the distribution of the species in the southwestern portion of the Driftless Area. Genotypic data from seven microsatellite loci were analyzed for 276 individuals from 15 localities representing major drainages within the region in northeast Iowa. Broad scale environmental variables including hydrologic, soil, and climatic factors were evaluated to construct an ecological niche model (ENM) to predict the suitability of habitat for the species within the region. Results of the genetic analyses revealed two distinct, but somewhat admixed genetic clusters of longnose dace in Iowa. The genetic differentiation between localities and between drainages was low to moderate with some evidence of isolation by distance. Most of the variation was observed by differences between individuals within local populations. The ENM generated largely reflected the known distribution of the species in Iowa with a decreasing probability of suitable habitat from northern to southern drainages. Geologic factors played a key role in the model. The distribution and population structure of the longnose dace in the northeast Iowa revealed that isolation by distance, historical processes and the underlying geology are primarily responsible for the observed spatial distribution of genetic variation.     

Going,going, gone: evidence for loss of an endemic species pair of threespine sticklebacks (<Emphasis Type="Italic">Gasterosteus aculeatus</Emphasis>) with implications for protection under species-at-risk legislation

Genomic extinction occurs when the unique combination of genetic traits that characterize distinct phenotypes are eliminated by introgressive hybridization even if population size is greater than zero. Benthic and limnetic threespine sticklebacks (Gasterosteus aculeatus) constitute reproductively isolated undescribed biological species that have evolved independently in several lakes in southwestern British Columbia, Canada (known as “species pairs” in each lake). Here we investigated whether the two species that comprise the pair from Enos Lake, southeastern Vancouver Island, remain as two distinct gene pools. Multi-season samples (>1200 fish) obtained over two years from throughout the lake and assayed for variation in morphological traits characteristic of the two species (i.e., body depth, dorsal spine count, gill raker counts) and at 12 microsatellite DNA loci consistently indicated the existence of only a single group of sticklebacks. There was no consistent evidence of two groups in any morphological trait, and mean gill raker counts were consistently intermediate (20–21) to those of known benthics (~18) and limnetics (~24) which together comprised strikingly bimodal distributions in historical samples. Genetic analyses employing model-based clustering also consistently indicated the presence of only a single genetic group of sticklebacks. Compared to historical samples and to benthics and limnetics from other lakes, no Enos Lake fish could be identified confidently as a pure benthic or limnetic. Our results provide the strongest evidence yet that the Enos Lake sticklebacks now consist of a single morphological and genetic population of sticklebacks, that the unique combination of genetic and morphological traits that characterized benthic and limnetic sticklebacks no longer exist, and that their current status under Canada’s Species-at Risk Act as Endangered should be re-evaluated.     

Population genetics of a widely distributed small freshwater fish with varying conservation concerns: the southern purple-spotted gudgeon, <Emphasis Type="Italic">Mogurnda adspersa</Emphasis>

Genetic variation plays a pivotal role in species viability and the maintenance of population genetic variation is a main focus of conservation biology. Threatened species often show reduced genetic variation compared to non-threatened species, and this is considered indicative of lowered evolutionary potential, compromised reproductive fitness, and elevated extinction risk. The southern purple-spotted gudgeon, Mogurnda adspersa, is a small freshwater fish with poor dispersal potential that was once common throughout the Murray–Darling Basin (MDB) and along the central east coast of Australia. Its numbers and distribution have shrunk dramatically in the MDB due to flow alteration, degradation of habitat, decreasing water quality, and introduction of alien species. We used microsatellite DNA markers to assess population structure and genetic variation at both large (i.e. across basin) and fine (i.e. within river catchments) spatial scales using a substantial sampling effort across the species range (n = 579 individuals; 35 localities). The results consistently indicated very low levels of genetic variation throughout, including along the east coast where the species is relatively common. At the broader scale, three highly differentiated groups of populations were found, concordant with previously reported genealogical distinctiveness. Hence we propose each group as a distinct Evolutionarily Significant Unit. We also inferred a minimum of 12 management units in M. adspersa, with no appreciable gene flow between them. Our study discloses findings relevant for both long- and short-term management, as it informs on the geographic context in which conservation priorities should be defined and specifies biological units for population monitoring and translocations.     

Population genetic patterns in an irruptive species,the long-nosed bandicoot (<Emphasis Type="Italic">Perameles nasuta</Emphasis>)

Understanding the genetic diversity of a population is important for understanding population persistence and extinction risk. The long-nosed bandicoot (Perameles nasuta) was once regarded as common throughout its range, but it is unknown whether it is at risk of decline and the genetic diversity in this species has not been assessed. We evaluated the genetic structure and diversity of a P. nasuta population from samples collected during a 6 year demographic study that encompassed a cyclical fluctuation in abundance. Genetic diversity was higher compared to other studies on bandicoot species suggesting the population is not genetically impoverished. We detected significant temporal genetic differentiation suggesting turnover of genotypes. There was no strong evidence for population structuring, indicating a panmictic population. Individual-based spatial autocorrelation analysis generated a similar pattern of relatedness across geographical distances for both sexes suggesting no or limited sex-biased dispersal. This study provides useful baseline genetic data for a large P. nasuta population that is not significantly impacted by introduced predators or habitat destruction.     

Population genetic diversity of the rare hardwood butternut (<Emphasis Type="Italic">Juglans cinerea</Emphasis>) in the northeastern USA

Populations of butternut tree (Juglans cinerea) have undergone range-wide extirpation. A fungal pathogen, Ophiognomonia clavigignenti-juglandacearum, of unknown origin has been recognized as the causal factor. This population collapse has allowed for observations of a broadleaf hardwood in rapid decline. This study made use of six neutral microsatellite markers to describe the present genetic diversity of butternut in the northeastern USA. Our results indicated weak population differentiation (F _ST?=?0.084), further supported by an absence of regional genetic structure. Despite reports of high mortality rates, genetic analysis revealed no sign of a recent bottleneck. Population statistics and Bayesian analysis indicated significant historical gene flow among butternut populations of the northeast. Attention should be given to genetic differences between upland and riparian habitat as riparian populations appear to contain greater allele diversity.     

Spatial genetic structure of an endangered orchid <Emphasis Type="Italic">Cypripedium calceolus</Emphasis> (Orchidaceae) at a regional scale: limited gene flow in a fragmented landscape

Plant species that are capable of propagating clonally are expected to be less vulnerable to habitat fragmentation due to their long life span. Cypripedium calceolus L. is a rare, clonal, long-lived orchid species. It has suffered marked decline because of habitat loss and fragmentation and over-collection, yet an IUCN report on this species does not regard fragmentation as a major threat to the species. We applied 13 nuclear microsatellites and cpDNA sequences to identify the patterns of population structure, genetic diversity and connectivity of six remnant local populations of C. calceolus in highly fragmented Gdańsk Pomerania region (N Poland). Despite severe (80%) loss of localities in the studied area we found that the local populations retain high levels of clonal (R 0.86–1) and genetic diversity (H_e = 0.572). However, their differentiation is relatively high (F_ST = 0.132 for nuclear SSR and F_ST = 0.363 for cpDNA) despite close geographic proximity (0.6–57 km). Bayesian clustering classified populations according to their geographic origin with little admixture. Low genetic connectivity between the remnant populations shows that the current gene flow is too low to serve as a cohesive force in a fragmented habitat, which may impede a quick response to environmental change. The species’ ability to retain ancestral variation may help withstand fragmentation, but in the light of observed extirpation rate it should be rather considered as a factor that only delays local populations’ extinction. This leads to the conclusion that habitat loss and fragmentation should be regarded as a real threat to stability of C. calcelolus populations.     

Molecular and morphological data suggest weak phylogeographic structure in the fairy shrimp <Emphasis Type="Italic">Streptocephalus torvicornis</Emphasis> (Branchiopoda,Anostraca)

Lake Tanganyika has undergone substantial climate-driven lake level fluctuations that have repeatedly changed the distribution and extent of habitat for endemic fishes. Here we consider whether patterns of population genetic structure and phenotypic divergence within the cichlid fish Telmatochromis temporalis have been affected by changing lake levels. The species has a large-bodied rock-living ecomorph and a small-bodied shell-living ecomorph, and both are found in close proximity in littoral habitats. Using mtDNA sequences we found that geographically distant (>50 km) populations within the southern lake region diverged approximately 130,000–230,000 years ago, suggesting that the regional genetic structure persisted through a low stand of over 400 m ~106,000 years ago that ended with a rise to present levels ~100,000 years ago. We also found signatures of large population expansions since this rise across the study region, suggesting that the populations positively responded to new habitat as lake levels rose to present levels. Finally, we found that geographically adjacent (<10 km) ecomorphs exhibit both significant genetic differentiation and signatures of gene flow after the lake level rise. The results suggest that local ecomorph divergence progressed with gene flow after the last major rise in lake level ~100,000, potentially facilitated by new ecological opportunities.     

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.     

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.     

Mediterranean lineage endemism,cold-adapted palaeodemographic dynamics and recent changes in population size in two solitary bees of the genus <Emphasis Type="Italic">Anthophora</Emphasis>

Anthophora plumipes is a solitary bee species common in Europe, Northern Africa, and the Middle East. Its sibling species A. villosula, which inhabits Eastern Asia, was recently introduced to the USA from Japan and has become naturalized there. The phylogeographic pattern in both species is unknown. Therefore, they are appropriate models for a phylogeographic study addressing overall genetic structure and colonization history. Analyses based on 11 microsatellite loci and a 727-bp cytochrome oxidase I (COI) sequence in samples from 41 localities, including the USA and Japan, revealed the presence of divergent clusters with strong geographic patterns. Both nuclear and mitochondrial markers show a significant genetic differentiation of A. villosula from A. plumipes, supporting their status as separate species. Several unique and divergent COI haplotypes in Spain, Greece and Israel indicate a high level of Mediterranean endemism, likely resulting from post-glacial areal contraction and fragmentation. A Bayesian skyline plot analysis suggests palaeodemographic dynamics typical of cold-adapted species — a stable effective population size during the ice age and its accelerated decrease after the glacial maximum. Recently, population sizes have increased and stabilized with land urbanization. A Bayesian clustering analysis of the microsatellite data only partially supported the Mediterranean COI groups, likely suggesting recent admixture of formerly isolated populations. Similarly, the British localities formed a separate cluster based on microsatellite markers, which was not supported by mitochondrial DNA. Analyses based on an isolation with migration model revealed a low effective population size for the British population and suggested asymmetric gene flow, primarily from continental Western Europe to the British Isles.     

Specific biological features and genetic variation of Chinese sleeper <Emphasis Type="Italic">Perccottus glenii</Emphasis> (Odontobutidae) in aquatic bodies of Tyumen oblast

Specific biological features, morphology, and genetic variation of an invasive species, the Chinese sleeper Perccottus glenii, in several lake and river ecosystems of the Tyumen oblast have been studied. This species displays relatively high rate of linear and weight growths. The main feed of the Chinese sleeper in both the river and lake ecosystems is the chironomid larvae. The diet is richer in the river ecosystem; predation plays an important role; and cannibalism is observed. As has been shown, the qualitative and quantitative characteristics of the Chinese sleeper infestations with local helminth species are by one order of magnitude lower as compared with the native fish species. A significant infestation rate is observed only for Nippotaenia mogurndae, a parasite specific for the Chinese sleeper. The population of this introduced species displays a high genetic variation for DNA markers. The rate of polymorphic ISSR bands is 73% and Nei’s genetic diversity is 0.26. The Chinese sleeper populations in the not directly connected river and lake (distance, 90 km) display a genetic identity of 99.5%, suggesting the absence of genetic differentiation of local populations, explainable by their recent origin from a single source of invasion. Morphological differences of the Chinese sleeper in different ecosystems appear on the same genetic basis and suggest a wide reaction norm characteristic of this species, underlying its ecological plasticity.     

Diversity and succession of pelagic microorganism communities in a newly restored Illinois River floodplain lake

Stenotopic specialization to a fragmented habitat promotes the evolution of genetic structure. It is not yet clear whether small-scale population structure generally translates into large-scale intraspecific divergence. In the present survey of mitochondrial genetic structure in the Lake Tanganyika endemic Altolamprologus (Teleostei, Cichlidae), a rock-dwelling cichlid genus comprising A. compressiceps and A. calvus, habitat-induced population fragmentation contrasts with weak phylogeographic structure and recent divergence among genetic clades. Low rates of dispersal, perhaps along gastropod shell beds that connect patches of rocky habitat, and periodic secondary contact during lake level fluctuations are apparently sufficient to maintain genetic connectivity within each of the two Altolamprologus species. The picture of genetic cohesion was interrupted by a single highly divergent haplotype clade in A. compressiceps restricted to the northern part of the lake. Comparisons between mitochondrial and nuclear phylogenetic reconstructions suggested that the divergent mitochondrial clade originated from ancient interspecific introgression. Finally, ‘isolation-with-migration’ models indicated that divergence between the two Altolamprologus species was recent (67–142 KYA) and proceeded with little if any gene flow. As in other rock-dwelling cichlids, recent population expansions were inferred in both Altolamprologus species, which may be connected with drastic lake level fluctuations.     

Genetic patterns and conservation of the Scarlet Macaw (<Emphasis Type="Italic">Ara macao</Emphasis>) in Costa Rica

Once widely distributed throughout the lowland forests of Costa Rica, scarlet macaws (Ara macao) have been reduced to two major, geographically separated, populations along the Pacific slope. Past demographic declines raise conservation concerns regarding the detrimental effects of population fragmentation. This investigation aimed to evaluate the current status of scarlet macaws along the Pacific slope by examining levels of genetic variation and patterns of genetic structure within and among remnant populations. Statistical analyses using multilocus genotypes revealed strong differentiation between Central and South Pacific populations, suggesting local geographic barriers have historically restricted gene flow between these localities. High genetic diversity suggests neither population suffers from genetic erosion, likely resulting from relatively large population sizes and high dispersal capacity and longevity. However, evidence of disequilibrium within the Central Pacific population infers anthropogenic threats have disrupted natural population dynamics. These results advocate on focusing available resources on habitat restoration and nest protection, as a means to assist in reestablishing demographic stability and maintain the genetic health of wild scarlet macaws in Costa Rica.     

Genetic diversity and structure of <Emphasis Type="BoldItalic">Crotalus triseriatus</Emphasis>, a rattlesnake of central Mexico

The isolated and fragmented populations are highly susceptible to stochastic events, increasing the extinction risk because of the decline in putative adaptive potential and individual fitness. The population has high heterozygosity values and a moderate allelic diversity, the heterozygosity values are higher than in most other Crotalus species and snake studies. Possibly these high levels of genetic diversity can be related to a large founder size, high effective population size, multiple paternity and overlapping generations. We did not find the genetic structuring but the effective number of alleles \((N_{\mathrm{e}})\) was 138.1. We found evidence of bottlenecks and the majority of rattlesnakes were unrelated, despite the small sample size, endemic status, the isolated and fragmented habitat. The genetic information provided in this study can be useful as a first approach to try to make informed conservation efforts for this species and also, important to preserve the habitat of this species; the endangered Abies–Pinus forest of the Nevado the Toluca Volcano.     

A complex history of introgression and vicariance in a threatened montane skink (<Emphasis Type="Italic">Pseudemoia cryodroma</Emphasis>) across an Australian sky island system

Species endemic to sky island systems are isolated to mountain peaks and high elevation plateaux both geographically and ecologically, making them particularly vulnerable to the effects of climate change. Pressures associated with climate change have already been linked to local extinctions of montane species, emphasizing the importance of understanding the genetic diversity and population connectivity within sky islands systems for the conservation management of remaining populations. Our study focuses on the endangered alpine skink Pseudemoia cryodroma, which is endemic to the Victorian Alps in south-eastern Australia, and has a disjunct distribution in montane habitats above 1100 m a.s.l. Using mitochondrial DNA (mtDNA) and microsatellite loci, we investigated species delimitation, genetic connectivity and population genetic structure across the geographic range of this species. We found discordance between genetic markers, indicating historical mtDNA introgression at one of the study sites between P. cryodroma and the closely related, syntopic P. entrecasteauxii. Molecular diversity was positively associated with site elevation and extent of suitable habitat, with inbreeding detected in three of the five populations. These results demonstrate the complex interaction between geography and habitat in shaping the population structure and genetic diversity of P. cryodroma, and highlight the importance of minimising future habitat loss and fragmentation for the long-term persistence of this species.     

Population size and land use affect the genetic variation and performance of the endangered plant species <Emphasis Type="Italic">Dianthus seguieri</Emphasis> ssp. <Emphasis Type="Italic">glaber</Emphasis>

Human activity and land use changes in the past decades have led to landscape homogenization and small-scale fragmentation of grassland habitats in most regions of central Europe. As a result, populations of many grassland species are small and strongly fragmented, facing extinction due to genetic depauperation and local maladaptation in remnant habitats. In this study, remaining populations of the strongly endangered grassland species Dianthus seguieri ssp. glaber (“Ragged Pink”) in Bavaria were investigated in order to evaluate the environmental factors influencing its genetic variation and performance. We first evaluated habitat, vegetation and population structure. Species performance was then studied by assessing the number of generative shoots, flowers and fertile capsules; and evaluating seed weight and seed viability. Finally, genetic variation was analyzed using molecular markers (AFLPs). Our analyses revealed that population size and land use abandonment have the strongest impact on genetic variation and species’ performance. Large and extended populations were most variable. 72 % of overall genetic variability of Dianthus seguieri ssp. glaber was found to be within populations, whereas 28 % remained between populations. Increased vegetation height and coverage, and a high proportion of gramineous species resulting from the lack of land use, reduced genetic variation, effective fruit and seed set. Our study shows that both population size and land use abandonment need to be considered to ensure the long term protection of endangered plant species. Maintaining an open habitat structure and adequate soil nutrient conditions through targeted annual mowing regime, over-storey vegetation trimming and green waste removal and the establishment of vegetation buffer strips will allow this species’ persistence and continuous recruitment.     

Genetic variation and differentiation in striped field mouse <Emphasis Type="Italic">Apodemus agrarius</Emphasis> inferred from RAPD-PCR analysis

Genetic variation and differentiation of the trans-Palearctic species Apodemus agrarius (striped field mouse), whose range consists of two large isolates—European-Siberian and Far Eastern-Chinese, were examined using RAPD-PCR analysis. The material from the both parts of the range was examined (41 individual of A. agrarius from 18 localities of Russia, Ukraine, Moldova, and Kazakhstan); the Far Eastern-Chinese part was represented by samples from the Amur region, Khabarovsk krai, and Primorye (Russia). Differences in frequencies of polymorphic RAPD loci were found between the European-Siberian and the Far Eastern population groups of striped field mouse. No “fixed” differences between them in RAPD spectra were found, and none of the used statistical methods permitted to distinguish with absolute certainty animals from the two range parts. Thus, genetic isolation of the European-Siberian and the Far Eastern population groups of A. agrarius is not strict. These results support the hypothesis on recent dispersal of striped field mouse from East to West Palearctics (during the Holocene climatic optimum, 7000 to 4500 years ago) and subsequent disjunction of the species range (not earlier than 4000–4500 years ago). The Far Eastern population group is more polymorphic than the European-Siberian one, while genetic heterogeneity is more uniformly distributed within it. This is probably explained by both historical events that happened during the species dispersal in the past, and different environmental conditions for the species in different parts of its range. The Far Eastern population group inhabits the area close to the distribution center of A. agrarius. It is likely that this group preserved genetic variation of the formerly integral ancestral form, while some amount of genetic polymorphism could be lost during the species colonization of the Siberian and European areas. To date, the settlement density and population number in general are higher than within the European-Siberian isolate, which seems to account for closer interpopulation associations, intense genetic exchange, and “smoothing” of polymorphism within the Far Eastern population group of A. agrarius.     

Development of subfossil <Emphasis Type="Italic">Daphnia</Emphasis> and <Emphasis Type="Italic">Chaoborus</Emphasis> assemblages in relation to progressive acidification and fish community alterations in SW Sweden

Dated sediment cores from acidified and fishless Lake Gaffeln and Lake Härsvatten, SW Sweden, were analyzed for Daphnia ephippia and Chaoborus mandibles to test whether acidification history and fish extirpations could be reconstructed in a paleo-study using these easily identifiable animal remains. According to monitoring data fish were lost in both lakes from the 1950s to the 1970s. Progressive acidification prior to monitoring was confirmed by a gradual decrease and eventual loss of Daphnia ephippia in both study lakes during the first half of the twentieth century. In Lake Gaffeln mandibles of C. obscuripes appeared immediately after fish loss in 1973, and the regular presence of this species confirmed the succeeding fishless state of this lake. In Lake Härsvatten sediments C. obscuripes appeared only recently, i.e. three decades after fish extirpation, showing that the absence of C. obscuripes mandibles is not a trustworthy indicator of fish presence. Hence, the appearance of C. obscuripes was not temporally related to fish loss but confirmed the present fishless condition. Known historical presence of cyprinid fish in Lake Gaffeln was confirmed by a significantly higher proportion of fragmented mandibles of C. flavicans compared to the historically cyprinid-free Lake Härsvatten. In addition, both lake profiles displayed zero-proportions of fragmented mandibles during fishless periods. We conclude that acidification history and fish extirpations can be inferred by integrated studies on subfossil Daphnia ephippia and Chaoborus mandibles. However, during extreme ultra-oligotrophic conditions in acidified clear-water lakes subfossil Chaoborus mandibles may be too scarce to infer fish absence/presence.     

Narrow endemics in Mediterranean scrublands: high gene flow buffers genetic impoverishment in the annual monospecific <Emphasis Type="Italic">Castrilanthemum</Emphasis> (Asteraceae)

Castrilanthemum debeauxii is a critically endangered annual plant narrowly distributed in mountains of SE Iberia. It occurs in spiny scrublands on limestone soils dominated by Erinacea anthyllis at medium altitudes. Phylogenetic results indicate that the monotypic Castrilanthemum constitutes a paleoendemic lineage that diverged from its closest extant relatives in the Miocene. To achieve a better understanding of its recent evolution and conservation status, we performed an analysis of genetic variation and structure of four subpopulations using plastid haplotypes and AFLPs. We also investigated additional characteristics (ecological requirements, reproductive biology, pre-dispersal seed predation) that are relevant to evaluate the conservation status of the species. Castrilanthemum was found to be a facultative selfer with no major germination limitations. We detected moderate levels of genetic diversity based on AFLPs and plastid DNA sequences. The low genetic structure found for both nuclear and plastid markers, together with species distribution modeling results, pointed to high gene flow, which might counteract processes of genetic erosion caused by the low number of individuals. We found significant levels of pre-dispersal seed predation by the burrowing larvae of a tephritid fly, which may have contributed to the decline of the populations. Based on our results, we suggest directions for the management of Castrilanthemum. In particular, we recommend seeding and collection of seeds for banks, and discuss the possibilities of population reinforcement and reintroduction in localities where the species is currently extinct.