Integrative taxonomy reveals Europe's rarest songbird species,the Gran Canaria blue chaffinch Fringilla polatzeki

The conservation of endangered taxa often critically depends on accurate taxonomic designations. The status of the Gran Canaria population of the blue chaffinch Fringilla teydea polatzeki has not been reevaluated since the early 1900s when this taxon was described as a subspecies and combined with the much more common Tenerife blue chaffinch F. t. teydea in a single species. We show that multiple diagnostic differences in plumage, songs, calls and morphometrics distinguish F. t. polatzeki from F. t. teydea. Preliminary playback experiments suggest that F. t. polatzeki is able to discriminate between songs of both taxa. Along with previously reported differences in mitochondrial DNA, these findings show that the blue chaffinches on Gran Canaria and Tenerife represent two distinctive species: F. polatzeki and F. teydea. Gran Canaria blue chaffinch is Europe's rarest passerine species and should be classified as critically endangered. Its long‐term survival in the wild currently depends on a very small (< 20 km²) area in southwest Gran Canaria. Reclassification of Gran Canaria blue chaffinch as a species increases the urgency of ongoing conservation efforts. Our study underscores the critical importance of taxonomic clarification of threatened taxa that are currently classified as ‘subspecies’.     

Mitochondrial DNA control region diversity in the endangered blue chaffinch, Fringilla teydea

The blue chaffinch (Fringilla teydea) is found only on the two central Canary Islands of Gran Canaria and Tenerife, where it is restricted to pine forest habitat. It is reasonably abundant on the latter island but endangered on the former. Here, sequence variation was studied in a fragment spanning domains I and II of the mitochondrial DNA (mtDNA) control region. Phylogenetic analysis of all haplotypes with a F. coelebs outgroup indicated the two island populations were reciprocally monophyletic, supporting their individual conservation. Unlike in other species, most within-island haplotype diversity was due to mutations in the domain II region. Surprisingly, genetic diversity was greater in the smaller Gran Canarian population. We suggest that this is unlikely to be maintained under current population sizes although it may be mitigated by incorporating genetic information into the captive breeding programme.     

Microsatellite loci isolation in the endangered Gran Canarian blue chaffinch (Fringilla teydea polatzeki) and their utility in closely related taxa

The blue chaffinch, Fringilla teydea, is an endemic species of the Canary Islands. This species is formed by two subspecies: The Teneriffean blue chaffinch (F. t. teydea), and the endangered Gran Canarian blue chaffinch, (F. t. polatzeki). Here we report the isolation and characterization of nine tetranucleotide microsatellites (AAAG and AAAT) from the Gran Canarian subspecies, using an enrichment protocol. An average of 7.8 alleles per locus and an average observed heterozygosity of 0.773 were found (n = 28). The loci were tested for their ability to cross amplify in the Teneriffean subspecies and in the common chaffinch (Fringilla coelebs). These microsatellites will be used to manage a captive breeding programme for the endangered Gran Canarian subspecies.     

Spatiotemporal variation of a <Emphasis Type="Italic">Pinus</Emphasis> seed rain available for an endemic finch in an insular environment

A major goal of avian ecological research is to determine how distribution and abundance of preferred resources available influence population dynamics and contribute to understand life-history characteristics. Food is widely considered the ultimate factor influencing these traits. We studied, with seed traps, the spatiotemporal variability of Pinus canariensis seed rain during 2007–2008, as a means to explain why a post-dispersal seed predator of conservation concern, the endemic blue chaffinch Fringilla teydea, can adjust its annual life cycle with this variation in an insular environment. Generalized linear mixed models and geostatistical tools were used. Results highlight that temperature and relative humidity are important predictors of seed release rates. Additionally, a high temporal variation was detected in seed abundance (i.e., peaks of massive seed release during the summer months, intermediate values in the autumn, and minimum release rates in winter and spring). Finally, within-stand spatial variation in seed flux was surprisingly large with the most productive microsites receiving three to four times more seeds than the least productive ones. Pine seeds showed a high protein value and a low germination rate. Based on these findings, we suggest that the fortunes of the blue chaffinch should be intimately related to spatiotemporal annual P. canariensis seed crops, temperature acting as a proximate cue, and food availability as the ultimate factor. For the endangered blue chaffinch population on Gran Canaria, we recommend, until more data are available, improving the seed supply during the winter season, either artificially (feeders) or naturally (planting Myrica faya shrubs).     

Species identification and genetic structure of threatened seahorses in Gran Canaria Island (Spain) using mitochondrial and microsatellite markers

A non-invasive DNA analysis of seahorse populations was carried out after extensive underwater surveys in Gran Canaria Island (Spain). In this geographical area, the presence of two species, Hippocampus hippocampus and H. guttulatus, has been previously reported. Sequencing of 16S ribosomal DNA (16S rDNA) was used for specific identification of live seahorses sampled in situ, as a previous step to evaluate genetic structure based on ten microsatellite markers. Phylogenetic analyses revealed the presence of a single species, H. hippocampus, in the seahorse communities found at Gran Canaria. No evidences of H. guttulatus or interspecific hybrids were found based on 16S rDNA and microsatellite data. The nuclear markers revealed low genetic diversity and lack of population structure across populations of Gran Canaria Island, with evidence of small population sizes. This study provides critical information to support conservation strategies of Gran Canaria seahorses.     

Conservation implications of high genetic variation in two closely related and highly threatened species of Crambe (Brassicaceae) endemic to the island of Gran Canaria: C. tamadabensis and C. pritzelii

We used data from 12 allozyme loci for two endemic Brassicaceae from Gran Canaria (the endangered narrow endemic Crambe tamadabensis and its more widespread congener C. pritzelii) to assess whether their genetic diversity patterns reflect their phylogenetic closeness and contrasting population sizes and distribution areas, and to derive conservation implications. Genetic diversity values are high for both species and slightly higher in C. tamadabensis, despite its narrow distribution in north‐western Gran Canaria. At odds with the generally high interpopulation diversity levels reported in Canarian endemics, values of G_ST in C. tamadabensis and C. pritzelii are rather low (0.067 and 0.126, respectively). We construe that the higher genetic structure detected in C. pritzelii is mainly a result of unbalanced allele frequencies and low population sizes at the edges of its distribution. The overall high allozyme variation detected in C. tamadabensis and C. pritzelii is nevertheless compatible with an incipient but consistent genetic differentiation between the two species, modulated by recurrent bottlenecks caused by grazing and drift. Our data suggest that conservation efforts aimed at maintaining the existing genetic connectivity in each species and ex situ conservation of seeds are the best strategies to conserve their genetic diversity.     

High genetic diversity despite drastic bottleneck in a critically endangered,long‐lived seabird,the Mascarene Petrel Pseudobulweria aterrima

The Mascarene Petrel Pseudobulweria aterrima is a critically endangered seabird endemic to Reunion Island, with an extremely small population suffering several threats. Fifteen polymorphic microsatellite loci were isolated from this species to analyse genetic diversity, estimate contemporary effective population size, search for evidence of a population bottleneck and see whether results support the hypothesis that life history traits could preserve allelic diversity in small populations. Results from 22 individuals found grounded as a consequence of light pollution highlight a surprisingly high genetic diversity, an absence of inbreeding, a contemporary effective population size estimated at approximately 1211 individuals and a probable bottleneck around 10 000 generations ago. Additional studies on genetic diversity and structure from a larger number of samples are thus required to evaluate the evolutionary potential of this critically endangered species.     

Genetic diversity of North American captive‐born gorillas (Gorilla gorilla gorilla)

Western lowland gorillas (Gorilla gorilla gorilla) are designated as critically endangered and wild populations are dramatically declining as a result of habitat destruction, fragmentation, diseases (e.g., Ebola) and the illegal bushmeat trade. As wild populations continue to decline, the genetic management of the North American captive western lowland gorilla population will be an important component of the long‐term conservation of the species. We genotyped 26 individuals from the North American captive gorilla collection at 11 autosomal microsatellite loci in order to compare levels of genetic diversity to wild populations, investigate genetic signatures of a population bottleneck and identify the genetic structure of the captive‐born population. Captive gorillas had significantly higher levels of allelic diversity (t₇ = 4.49, P = 0.002) and heterozygosity (t₇ = 4.15, P = 0.004) than comparative wild populations, yet the population has lost significant allelic diversity while in captivity when compared to founders (t₇ = 2.44, P = 0.04). Analyses suggested no genetic evidence for a population bottleneck of the captive population. Genetic structure results supported the management of North American captive gorillas as a single population. Our results highlight the utility of genetic management approaches for endangered nonhuman primate species.     

GENETIC STRUCTURE OF NATURAL POPULATIONS IN THE RED ALGAE GELIDIUM CANARIENSE (GELIDIALES,RHODOPHYTA) INVESTIGATED BY RANDOM AMPLIFIED POLYMORPHIC DNA (RAPD) MARKERS1

Random amplified polymorphic DNA (RAPD) marker variation was analyzed in female gametophytes in natural populations of Gelidium canariense (Grunow) Seoane‐Camba ex Haroun, Gil‐Rodríguez, Diaz de Castro et Prud'Homme van Reine from the Canary Islands to estimate the degree and distribution of genetic variability and differentiation. A total of 190 haploid individuals were analyzed with 60 polymorphic RAPDs bands which produced 190 distinct multilocus genotypes. A high level of polymorphism was detected in all populations analyzed. Within‐population gene diversity ranged from 0.156 to 0.264. The populations on the island of Gran Canaria showed higher genetic variation than the other populations analyzed. The partitioning of molecular variance by analysis of molecular variance showed that most genetic variation resides within populations (68.85%). These results suggest that sexual reproduction is the predominant mode of reproduction for G. canariense gametophytic populations, and the main determinant in reaching high levels of genetic diversity. The Neighbor‐Joining tree and FCA analysis displayed two subclusters that correspond to the populations from the western islands (Tenerife, La Palma, Gomera) and the eastern island (Gran Canaria). In addition, we have detected a significant relationship between F_ST/(1?F_ST) and geographical distance consistent with data on water circulation and age of islands. The results obtained agree with an isolation by distance model, with gene flow from eastern to the western islands, and a high level of genetic differentiation between populations (F_ST=0.311, P<0.001).     

High biogeographical and evolutionary value of Canary Island pine populations out of the elevational pine belt: the case of a relict coastal population

Aim Marginal populations are frequently neglected in static views of vegetation types, particularly when defining conservation reserves. The biogeographical and evolutionary importance of a marginal and endangered population of Pinus canariensis is addressed in this study to ascertain the need for conservation action. Diversity loss between adults and offspring and patterns of seed dispersal and recruitment were examined to provide evidence of recent degradation of marginal P. canariensis pinewoods. The scientific basis for the provision of sound conservation policies was investigated by elucidating the factors responsible for significant population structure. Location An isolated low‐density pinewood community confined to the Arguineguin ravine, in south Gran Canaria, Canary Islands. Methods Two cohorts, of centenary trees (those older than 100 years) and young recruits, respectively, were found in a detailed inventory of the pine population in the Arguienguin ravine. Chloroplast and nuclear microsatellites were compared to assess the levels of genetic diversity between adults and recruits. Spatial genetic structure and parentage analysis based on highly polymorphic nuclear and chloroplast microsatellites were examined to test limitations in seed dispersal. The underlying environmental factors that led to a clustering effect in the population were tested using point pattern methodologies. Results Centenary trees retain high levels of genetic diversity and effective population size, suggesting a wider extension of the pinewood forests in the past. A significant loss of genetic diversity was detected between adults and recruits. Pinus canariensis dispersal distances were among the longest ever reported for anemochorous species, suggesting that environmental factors account for recruit clustering. Cluster models showed that recruits tend to aggregate in dry streambeds, where soil and water accumulation favours establishment. Main conclusions Boundary populations of P. canariensis are subjected to fragmentation and reduction in effective population size as a result of human impact. Marginal populations were denser in the past and currently require specific conservation efforts. A severe reduction in genetic diversity compromises the future of present populations. Streambeds appear to play a major role in recruit establishment, but data suggest the absence of limitations to seed dispersal.     

Preliminary assessment of the release of captive-bred Gran Canaria Blue Chaffinches Fringilla teydea polatzeki as a reinforcement population

Capsule: The endangered Gran Canaria Blue Chaffinch Fringilla teydea polatzeki has been bred in captivity with the aim of reinforcing wild populations. We released and monitored 26 males and 15 females between 2010 and 2012. Survival and reproductive success were similar between the reinforced population and a stable reference population, suggesting that the process could be useful for the conservation of the species.     

Bottlenecks and rescue effects in a fluctuating population of golden-mantled ground squirrels (Spermophilus lateralis)

Mammal species characterized by highly fluctuating populations often maintain genetic diversity in response to frequent demographic bottlenecks, suggesting the ameliorating influence of life history and behavioral factors. Immigration in particular is expected to promote genetic recovery and is hypothesized to be the most likely process maintaining genetic diversity in fluctuating mammal populations. Most demographic bottlenecks have been inferred retrospectively, and direct analysis of a natural population before, during, and after a bottleneck is rare. Using a continuous 10-year dataset detailing the complete demographic and genetic history of a fluctuating population of golden-mantled ground squirrels (Spermophilus lateralis), we analyzed the genetic consequences of a 4-year demographic bottleneck that reduced the population to seven adult squirrels, and we evaluated the potential “rescue effect” of immigration. Analysis of six microsatellite loci revealed that, while a decline in allelic richness was observed during the bottleneck, there was no observed excess of heterozygosity, a characteristic bottleneck signature, and no evidence for heterozygote deficiency during the recovery phase. In addition, we found no evidence for inbreeding depression during or after the bottleneck. By identifying immigrants and analyzing their demographic and genetic contributions, we found that immigration promoted demographic recovery and countered the genetic effects of the bottleneck, especially the loss of allelic richness. Within 3 years both population size and genetic variation had recovered to pre-bottleneck levels, supporting the role of immigration in maintaining genetic variation during bottleneck events in fluctuating populations. Our analyses revealed considerable variation among analytical techniques in their ability to detect genetic bottlenecks, suggesting that caution is warranted when evaluating bottleneck events based on one technique.     

Phylogeography and genetic structure of the Canarian common chaffinch (Fringilla coelebs) inferred with mtDNA and microsatellite loci

The widespread common chaffinch (Fringilla coelebs) inhabits five of the seven Canary Islands. Sequences of the mitochondrial cytochrome b gene (1002 bp) revealed new insights into the systematics and phylogeography of this taxon. Additionally, a set of microsatellite loci were analyzed to examine the structure of these populations. Our results suggest that a new species of the genus Fringilla is present in the Canary Islands, which comprises at least three subspecies, but with a different distribution to that which has been morphologically accepted. The specimens from Gran Canaria are genetically distinct from those of La Gomera and Tenerife (F. c. canariensis), which suggests the existence of an undescribed taxon. Furthermore, nuclear microsatellite data suggest an ongoing incipient speciation process in this population. This study provides both important conservationist implications and a basis for re-evaluating the taxonomic status of the Canarian Fringilla coelebs populations.     

Genetic signatures of population change in the British golden eagle (<Emphasis Type="Italic">Aquila chrysaetos</Emphasis>)

The golden eagle (Aquila chrysaetos) was once widely distributed in the uplands of the British Isles, but is now extinct in Ireland, and largely confined to the highlands and islands of Scotland. As the precise extent and severity of the reduction in population size are unclear, it is important to understand how the population was affected by the decline. We therefore genotyped 13 polymorphic microsatellite loci in 172 individuals from the contemporary British population and compared their genetic diversity to 70 British and 9 Irish museum specimens. Despite the recent population decline, there is only slight evidence for a concomitant loss of genetic variation. Instead, two likelihood-based Bayesian methods provided evidence for a severe ancient genetic bottleneck, possibly caused by the fragmentation of a large mainland European population and/or the founding effects of colonising the British Isles. As the population persisted despite this ancient bottleneck, our conclusion is that there is limited need for intervention to augment the present-day genetic diversity. The main short-term objective of conservation measures should be to increase population sizes by continuous safeguarding of individuals and habitat management. Finally, we also confirmed that, for management purposes, the species should be considered a single population unit and that the extinct Irish population was not differentiated from the British one.     

Genetic diversity in threatened Posidonia australis seagrass meadows

Recognising patterns of genetic diversity and connectivity is integral to understanding the mechanisms behind population declines and formulating management plans for the conservation of threatened or endangered species. This is particularly important for clonal organisms such as seagrasses, which are experiencing rapid global decline. This study quantifies genetic diversity within 12 naturally fragmented Posidonia australis meadows on the east coast of Australia, using a set of eight microsatellite DNA markers. Genetic diversity increased with latitude, moving away from the range-edge, and was significantly lower in six mid-range endangered meadows and the two northernmost meadows. These meadows also showed evidence of shared multilocus genotypes despite significant geographic separation. The four southernmost meadows were genetically differentiated from all other meadows further north, and all multilocus genotypes identified were unique to their sample locations. We conclude that patterns of low diversity in the endangered and northern meadows are likely due to a population bottleneck caused by a range-edge effect. A common ancestral source meadow existing prior to historical sea level changes may explain the sharing of multilocus genotypes, as contemporary gene flow between these geographically isolated meadows is unlikely. Our findings have important implications for conservation, highlighting the endangered and range-edge populations as those potentially most at risk of extinction should environmental conditions change. These results can be utilised for the location of suitable donor populations for transplanting purposes as a means of mitigating further declines.     

Loss of genetic diversity,recovery and allele surfing in a colonizing parasite,Geomydoecus aurei

Understanding the genetic consequences of changes in species distributions has wide‐ranging implications for predicting future outcomes of climate change, for protecting threatened or endangered populations and for understanding the history that has led to current genetic patterns within species. Herein, we examine the genetic consequences of range expansion over a 25‐year period in a parasite (Geomydoecus aurei) that is in the process of expanding its geographic range via invasion of a novel host. By sampling the genetics of 1,935 G. aurei lice taken from 64 host individuals collected over this time period using 12 microsatellite markers, we test hypotheses concerning linear spatial expansion, genetic recovery time and allele surfing. We find evidence of decreasing allelic richness (AR) with increasing distance from the source population, supporting a linear, stepping stone model of spatial expansion that emphasizes the effects of repeated bottleneck events during colonization. We provide evidence of post‐bottleneck genetic recovery, with average AR of infrapopulations increasing about 30% over the 225‐generation span of time observed directly in this study. Our estimates of recovery rate suggest, however, that recovery has plateaued and that this population may not reach genetic diversity levels of the source population without further immigration from the source population. Finally, we employ a grid‐based sampling scheme in the region of ongoing population expansion and provide empirical evidence for the power of allele surfing to impart genetic structure on a population, even under conditions of selective neutrality and in a place that lacks strong barriers to gene flow.     

Effective population size is strongly correlated with breeding pond size in the endangered California tiger salamander, <Emphasis Type="Italic">Ambystoma californiense</Emphasis>

Maintaining genetic diversity and population viability in endangered and threatened species is a primary concern of conservation biology. Genetic diversity depends on population connectivity and effective population size (N_e), both of which are often compromised in endangered taxa. While the importance of population connectivity and gene flow has been well studied, investigating effective population sizes in natural systems has received far less attention. However, N_e plays a prominent role in the maintenance of genetic diversity, the prevention of inbreeding depression, and in determining the probability of population persistence. In this study, we examined the relationship between breeding pond characteristics and N_e in the endangered California tiger salamander, Ambystoma californiense. We sampled 203 individuals from 10 breeding ponds on a local landscape, and used 11 polymorphic microsatellite loci to quantify genetic structure, gene flow, and effective population sizes. We also measured the areas of each pond using satellite imagery and classified ponds as either hydrologically-modified perennial ponds or naturally occurring vernal pools, the latter of which constitute the natural breeding habitat for A. californiense. We found no correlation between pond area and heterozygosity or allelic diversity, but we identified a strong positive relationship between breeding pond area and N_e, particularly for vernal pools. Our results provide some of the first empirical evidence that variation in breeding habitat can be associated with differences in N_e and suggest that a more complete understanding of the environmental features that influence N_e is an important component of conservation genetics and management.     

Genetic diversity,population genetic structure and demographic history of Przewalski’s gazelle (<Emphasis Type="Italic">Procapra przewalskii</Emphasis>): implications for conservation

The Przewalski’s gazelle (Procapra przewalskii) is one of the most endangered antelope species in the world. It is endemic to China and is a flagship species in the eastern part of the Qinghai–Tibet plateau. To establish effective conservation measures on this species, genetic information such as genetic structure is needed. However, there has not been a comprehensive genetic assessment on this gazelle using nuclear DNA markers yet. Here, we employed 13 microsatellite loci to investigate genetic diversity, population genetic structure and demographic history of Przewalski’s gazelle using noninvasive samples of 169 wild gazelles collected from nine populations. A total of 76 alleles were detected from the entire samples, mean allele number was 5.85, and overall H _O and H _E were 0.525 and 0.552, respectively. Structure and GENELAND analyses found six genetic groups in the nine populations. Between the inferred genetic groups, significant genetic differentiation and low migration rates were detected. Demographic analyses indicated that Przewalski’s gazelle experienced genetic bottleneck and severe population decline, with the ancestral effective population size reducing to less than one percent. Based on the results of this study, we provide several conservation recommendations for Przewalski’s gazelle, such as six management units, periodic monitoring and special conservation consideration on the Qiejitan population.     

Phylogeography of the blue tit ( Parus teneriffae -group) on the Canary Islands based on mitochondrial DNA sequence data and morphometrics

An analysis of the sequences of the mitochondrial cytochrome b gene (1005 bp) of the Parus teneriffae-group from the Canary Islands and North Africa revealed new insights into the phylogeography of this taxon. The origin of the radiation on the Canarian Archipelago was apparently one of the central islands—Tenerife or Gran Canaria. The populations on El Hierro (P. t. ombriosus) and La Palma (P. t. palmensis) represent distinct monophyletic lineages. Blue tits from Gran Canaria are genetically distinct from those of La Gomera and Tenerife (P. t. teneriffae), which supports the results of other studies and suggests the existence of an—until now—undescribed taxon there. In contrast, the populations on the eastern islands of Fuerteventura and Lanzarote (P. t. degener) could not be distinguished from North African blue tits (P. t. ultramarinus), and these populations should be subsumed under the subspecies ultramarinus. Taxonomic recommendations based on these results include the distinction of the northern European P. caeruleus from P. teneriffae, including blue tits from North Africa and the Canary Islands, the treatment of degener and ultramarinus as synonymous (P. teneriffae ultramarinus) and a new blue tit taxon on the island of Gran Canaria (P. t. hedwigii nov. ssp.), which is formally described. The genetic results are in parts supported by bioacoustic and morphological data.     

Microsatellite genetic variation in the Chinese endemic Eucommia ulmoides (Eucommiaceae): implications for conservation

Eucommia ulmoides, a traditional Chinese medicinal plant, is endangered as a consequence of long‐term and widespread harvest in the late 20th century. It has been widely cultivated as a source of herbal medicine and for use in the organic chemical industry in China. In this study, eight microsatellite markers were applied to investigate genetic diversity in E. ulmoides. Three hundred individuals from one semi‐wild population and nine cultivated populations across its main production area were collected. A high level of genetic diversity at population levels (H_E = 0.716) was observed. The highly outcrossed mating system, high longevity of E. ulmoides and seed admixture may be responsible for high genetic variation within populations. A genetic bottleneck was observed in one population. Populations were only slightly differentiated from one another (F_ST = 0.063); this was also supported by AMOVA, which revealed that 94.05% of the total variation resided within populations. This is probably attributable to long‐distance gene flow mediated by the exchange of seeds by local farmers. Implications of these results for the conservation of genetic resources of E. ulmoides are discussed. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 775–785.