Abstract
Eurasian Nuthatches have experienced a northward range expansion in Britain. Younger, more isolated, populations have smaller song meme-pool size, diversity and individual repertoires.
MULTILOCUS COALESCENCE ANALYSES SUPPORT A mtDNA-BASED PHYLOGEOGRAPHIC HISTORY FOR A WIDESPREAD PALEARCTIC PASSERINE BIRD, SITTA EUROPAEA
Abstract
Our understanding of species phylogeography in much of the Palearctic is incomplete. In addition, many existing studies based solely on mitochondrial DNA (mtDNA) can provide a biased view of phylogeographic history because of the effects of lineage sorting, natural selection, or hybridization. We analyzed 13 introns to assess a mtDNA study of the Eurasian nuthatch (Sitta europaea) that suggested a seemingly contemporaneous origin of distinct taxa in the Caucasus, Europe, and Asia. Neutrality tests showed no evidence of selection on either the mtDNA or nuclear sequences. Most nuclear gene trees, except for Z-linked ones, did not recover the three lineages, which we attribute to recent splitting. Analyses of the 13 introns combined revealed the same three groups as did the mtDNA and suggested that nuthatches experienced a trichotomous (or two indistinguishable) split(s) 1–2 million years ago (Mya) and have remained isolated with trifling if not zero gene flow since then, and the Asian group increased in population size. This result demonstrates the usefulness of mtDNA in discovering phylogeographic patterns. The use of multiple nuclear loci facilitated detection of an introgressed individual and improved estimates of process parameters such as divergence time and population expansion. We recommend that phylogeographic studies should be based on both mtDNA and nuclear genes.
Keywords
Coalescence;divergence time;intron;mtDNA;phylogeography;selection
Year-round territorial aggression is independent of plasma DHEA in the European nuthatch Sittaeuropaea
Abstract
Plasma testosterone can play an important role in promoting aggressive behaviors relating to territory defense in breeding male birds. Some birds defend territories also during the non-breeding phase, when testosterone circulates at basal levels. In such species, plasma levels of the pro-hormone dehydroepiandrosterone (DHEA) may support non-breeding territoriality by acting as a local substrate for sex steroids. To test this possible role of plasma DHEA, we examined the seasonal DHEA profile of male (and female) European nuthatches Sitta europaea: a male and female nuthatch pair will defend an all-purpose territory throughout the year. We hypothesized that plasma DHEA would be detectable in wintering nuthatches with a territory. However, only ca. half of the territorial wintering males (and females) displayed detectable DHEA levels, suggesting that plasma DHEA is not a major sex steroid precursor during non-breeding. Further, among hatching-year birds, plasma DHEA was significantly lower in territorial birds than in “floaters”, i.e., subordinate birds without a territory. To experimentally examine the role of DHEA in non-breeding territoriality, we treated adult wintering males with DHEA and measured effects on aggressive responses to conspecific challenge. DHEA treatment elevated plasma levels of DHEA (and testosterone), but did not enhance territorial behaviors or their persistence. Taken together, our data suggest that DHEA (and, indeed, sex steroids per se) do not regulate non-breeding territoriality in the nuthatch. Given that territorial aggression in nuthatches is expressed year-round, a hormone for its activation may be redundant.
Highlights
► We examine the seasonal DHEA profile in a year-round territorial songbird. ► We test effects of DHEA treatment on non-breeding territoriality in autumn. ► Plasma DHEA shows no seasonal variation and is often undetectable. ► DHEA treatment does not enhance non-breeding aggression or its persistence. ► We report that DHEA does not relate to non-breeding territoriality in this species.
Keywords
Nuthatch; Seasonal DHEA profile; Implant; Territorial aggression; Testosterone; Non-breeding; Wintering
Phylogeography and population structure of Krüper’s Nuthatch Sitta krueperi from Turkey based on microsatellites and mitochondrial DNA
Albayrak T, Gonzalez J., Drovetski S. V., Wink M. 2012. Phylogeography and population structure of Krüper’s Nuthatch Sitta krueperi from Turkey based on microsatellites and mitochondrial DNA. Journal of Ornithology, Vol. 153, Issue 2, pp 405-411.
Abstract
Krüper’s Nuthatch Sitta krueperi is endemic to Anatolia, Lesvos Island and the western Caucasus region where it inhabits coniferous forests. To infer the phylogeographic structure of Krüper’s Nuthatch, we analyzed partial sequences of the mitochondrial cytochrome oxidase subunit I gene (COI; 605 bp) and allele variation at eight microsatellite loci from birds sampled across five localities in Turkey. A total of ten COI haplotypes were found among 68 individuals revealing three distinct haplotype groups; one each in northwestern, northeastern, and southern Turkey. However, there was evidence for secondary gene flow between the northwestern and the other two regions. Significant microsatellite differentiation was also found between northern and southern localities, but not between the two northern ones. This genetic structure is consistent with the isolation of these populations in different glacial refugia followed by establishing secondary contact after glacial retreat. The identified populations of this ‘near threatened’ species should be treated as separate conservation units.
Abstract
Krüper’s Nuthatch Sitta krueperi is endemic to Anatolia, Lesvos Island and the western Caucasus region where it inhabits coniferous forests. To infer the phylogeographic structure of Krüper’s Nuthatch, we analyzed partial sequences of the mitochondrial cytochrome oxidase subunit I gene (COI; 605 bp) and allele variation at eight microsatellite loci from birds sampled across five localities in Turkey. A total of ten COI haplotypes were found among 68 individuals revealing three distinct haplotype groups; one each in northwestern, northeastern, and southern Turkey. However, there was evidence for secondary gene flow between the northwestern and the other two regions. Significant microsatellite differentiation was also found between northern and southern localities, but not between the two northern ones. This genetic structure is consistent with the isolation of these populations in different glacial refugia followed by establishing secondary contact after glacial retreat. The identified populations of this ‘near threatened’ species should be treated as separate conservation units.
Comparison of postfire mortality in endemic Corsican black pine (Pinus nigra ssp. laricio) and its direct competitor (Pinus pinaster)
Pimont F., Prodon R., Rigolot E. 2011. Comparison of postfire mortality in endemic Corsican black pine (Pinus nigra ssp. laricio) and its direct competitor (Pinus pinaster). Annals of Forest Science, Vol. 68, Issue 2, pp 425-432.
Abstract
Introduction
Laricio pine (Pinus nigra J.F. Arn. ssp. laricio (Poiret) Maire var Corsicana Hyl.) is a form of black pine endemic to Corsica, that may now be under threat due to current fire regimes and competition with maritime pine (Pinus pinaster Aiton).
Material and methods
This study aimed to compare postfire mortality in laricio and maritime pine in a mixed stand in northwest Corsica. Diameter at breast height, bark char, bole length charred, and tree mortality were measured in 661 trees 9 months after a severe fire. Logistic regressions were used to determine mortality probabilities which, to compare the two species, were expressed in relation to species, age, and species-independent severity indicators.
Results
For all ages considered, laricio pine mortality was up to threefold that of maritime pine. The differences between the species were most significant in pines less than 60 years old and exposed to severe conditions. This was mainly due to differences in growth rate between the two species.
Conclusion
Considering life history traits, maritime pine appears to be better adapted than laricio pine to the risk of fire. As the frequency of major fires in Corsica is on the increase, constituting a real threat for endemic species, we provide a few management guidelines for conservation of the laricio pine.
Abstract
Introduction
Laricio pine (Pinus nigra J.F. Arn. ssp. laricio (Poiret) Maire var Corsicana Hyl.) is a form of black pine endemic to Corsica, that may now be under threat due to current fire regimes and competition with maritime pine (Pinus pinaster Aiton).
Material and methods
This study aimed to compare postfire mortality in laricio and maritime pine in a mixed stand in northwest Corsica. Diameter at breast height, bark char, bole length charred, and tree mortality were measured in 661 trees 9 months after a severe fire. Logistic regressions were used to determine mortality probabilities which, to compare the two species, were expressed in relation to species, age, and species-independent severity indicators.
Results
For all ages considered, laricio pine mortality was up to threefold that of maritime pine. The differences between the species were most significant in pines less than 60 years old and exposed to severe conditions. This was mainly due to differences in growth rate between the two species.
Conclusion
Considering life history traits, maritime pine appears to be better adapted than laricio pine to the risk of fire. As the frequency of major fires in Corsica is on the increase, constituting a real threat for endemic species, we provide a few management guidelines for conservation of the laricio pine.
Conservation of the corsican nuthatch Sitta whiteheadi Sharpe, 1844: importance of forest management
BECK N. 1992. Conservation de la Sitelle Corse Sitta whiteheadi Sharpe, 1844: sa place dans les aménagements forestiers = Conservation of the corsican nuthatch Sitta whiteheadi Sharpe, 1844: importance of forest management. Travaux scientifiques du Parc naturel régional et des réserves naturelles de Corse, n°40, pp. 1-32.
Speciation in the White-breasted Nuthatch (Sitta carolinensis): a multilocus perspective
WALSTROM, V. W., KLICKA, J. and SPELLMAN, G. M. (2012), Speciation in the White-breasted Nuthatch (Sitta carolinensis): a multilocus perspective. Molecular Ecology, 21: 907–920.
Abstract
Inferring the evolutionary and ecological processes that have shaped contemporary species distributions using the geographic distribution of gene lineages is the principal goal of phylogeographic research. Researchers in the field have recognized that inferences made from a single gene, often mitochondrial, can be informative regarding the pattern of diversification but lack conclusive information regarding the evolutionary mechanisms that led to the observed patterns. Here, we use a multilocus (20 loci) data set to explore the evolutionary history of the White-breasted Nuthatch (Sitta carolinensis). A previous single-locus study found S. carolinensis is comprised of four reciprocally monophyletic clades geographically restricted to the pine and oak forests of: (i) eastern North America, (ii) southern Rocky Mountain and Mexican Mountain ranges, (iii) Eastern Sierra Nevada and Northern Rocky Mountains and (iv) Pacific slope of North America. The diversification of the clades was attributed to the fragmentation of North American pine and oak woodlands in the Pliocene with subsequent divergences owing to the Pleistocene glacial cycles. Principal component, clustering and species tree analyses of the multilocus data resolved the same four groups or lineages found in the single-locus study. Coalescent analyses and hypothesis testing of nested isolation and migration models indicate that isolation and not gene flow has been the major evolutionary mechanism responsible for shaping genetic variation, and all the divergence events within S. carolinensis have occurred in response to the Pleistocene glacial cycles.
Abstract
Inferring the evolutionary and ecological processes that have shaped contemporary species distributions using the geographic distribution of gene lineages is the principal goal of phylogeographic research. Researchers in the field have recognized that inferences made from a single gene, often mitochondrial, can be informative regarding the pattern of diversification but lack conclusive information regarding the evolutionary mechanisms that led to the observed patterns. Here, we use a multilocus (20 loci) data set to explore the evolutionary history of the White-breasted Nuthatch (Sitta carolinensis). A previous single-locus study found S. carolinensis is comprised of four reciprocally monophyletic clades geographically restricted to the pine and oak forests of: (i) eastern North America, (ii) southern Rocky Mountain and Mexican Mountain ranges, (iii) Eastern Sierra Nevada and Northern Rocky Mountains and (iv) Pacific slope of North America. The diversification of the clades was attributed to the fragmentation of North American pine and oak woodlands in the Pliocene with subsequent divergences owing to the Pleistocene glacial cycles. Principal component, clustering and species tree analyses of the multilocus data resolved the same four groups or lineages found in the single-locus study. Coalescent analyses and hypothesis testing of nested isolation and migration models indicate that isolation and not gene flow has been the major evolutionary mechanism responsible for shaping genetic variation, and all the divergence events within S. carolinensis have occurred in response to the Pleistocene glacial cycles.
Morphometric Variation and Population Relationships of Krüper's Nuthatch (Sitta krueperi) in Turkey
Albayrak Y., Besnard A., and Erdoǧan A. (2011). Morphometric Variation and Population Relationships of Krüper's Nuthatch (Sitta krueperi) in Turkey. The Wilson Journal of Ornithology 123(4):734-740.
Abstract
We studied the population relationships of Krüper's Nuthatch (Sitta krueperi) by capturing 82 individuals using mist nets in six different areas in Turkey during the breeding season, from March to June 2005–2008. Forty-one different morphometric characters were measured. Morphometric characters measured (x ¯ ± SD) were: body mass = 13.11 ± 0.88 g, wing length = 74.79 ± 2.35 mm, bill length = 17.65 ± 0.76 mm, and tarsus length = 19.10 ± 0.93 mm, respectively. A stepwise discriminant analysis of four populations retained seven statistically significant measurements: body mass, wing length, length of P 8, alula, bill height, back nail, and left nail. These analyses allowed discrimination among populations. The population in the Aladağlar Mountains differed from others even though it overlapped with the population in the Lütfi Büyük Yıldırım Research Forest, and marginally with the population at Kartalkaya Mountain. Cross validation for the other three populations confirmed large overlap in morphometric characteristics although the population at the Lütfi Büyük Yıldırım Research Forest seemed to be intermediate between populations at Aladağlar Mountains and in the Kazdağları Mountain-Kartalkaya Mountain complex.
Abstract
We studied the population relationships of Krüper's Nuthatch (Sitta krueperi) by capturing 82 individuals using mist nets in six different areas in Turkey during the breeding season, from March to June 2005–2008. Forty-one different morphometric characters were measured. Morphometric characters measured (x ¯ ± SD) were: body mass = 13.11 ± 0.88 g, wing length = 74.79 ± 2.35 mm, bill length = 17.65 ± 0.76 mm, and tarsus length = 19.10 ± 0.93 mm, respectively. A stepwise discriminant analysis of four populations retained seven statistically significant measurements: body mass, wing length, length of P 8, alula, bill height, back nail, and left nail. These analyses allowed discrimination among populations. The population in the Aladağlar Mountains differed from others even though it overlapped with the population in the Lütfi Büyük Yıldırım Research Forest, and marginally with the population at Kartalkaya Mountain. Cross validation for the other three populations confirmed large overlap in morphometric characteristics although the population at the Lütfi Büyük Yıldırım Research Forest seemed to be intermediate between populations at Aladağlar Mountains and in the Kazdağları Mountain-Kartalkaya Mountain complex.
Back from a Predicted Climatic Extinction of an Island Endemic: A Future for the Corsican Nuthatch
Barbet-Massin M, Jiguet F (2011) Back from a Predicted Climatic Extinction of an Island Endemic: A Future for the Corsican Nuthatch. PLoS ONE 6(3): e18228. doi:10.1371/journal.pone.0018228
Abstract
The Corsican Nuthatch (Sitta whiteheadi) is red-listed as vulnerable to extinction by the IUCN because of its endemism, reduced population size, and recent decline. A further cause is the fragmentation and loss of its spatially-restricted favourite habitat, the Corsican pine (Pinus nigra laricio) forest. In this study, we aimed at estimating the potential impact of climate change on the distribution of the Corsican Nuthatch using species distribution models. Because this species has a strong trophic association with the Corsican and Maritime pines (P. nigra laricio and P. pinaster), we first modelled the current and future potential distribution of both pine species in order to use them as habitat variables when modelling the nuthatch distribution. However, the Corsican pine has suffered large distribution losses in the past centuries due to the development of anthropogenic activities, and is now restricted to mountainous woodland. As a consequence, its realized niche is likely significantly smaller than its fundamental niche, so that a projection of the current distribution under future climatic conditions would produce misleading results. To obtain a predicted pine distribution at closest to the geographic projection of the fundamental niche, we used available information on the current pine distribution associated to information on the persistence of isolated natural pine coppices. While common thresholds (maximizing the sum of sensitivity and specificity) predicted a potential large loss of the Corsican Nuthatch distribution by 2100, the use of more appropriate thresholds aiming at getting closer to the fundamental distribution of the Corsican pine predicted that 98% of the current presence points should remain potentially suitable for the nuthatch and its range could be 10% larger in the future. The habitat of the endemic Corsican Nuthatch is therefore more likely threatened by an increasing frequency and intensity of wildfires or anthropogenic activities than by climate change.
Abstract
The Corsican Nuthatch (Sitta whiteheadi) is red-listed as vulnerable to extinction by the IUCN because of its endemism, reduced population size, and recent decline. A further cause is the fragmentation and loss of its spatially-restricted favourite habitat, the Corsican pine (Pinus nigra laricio) forest. In this study, we aimed at estimating the potential impact of climate change on the distribution of the Corsican Nuthatch using species distribution models. Because this species has a strong trophic association with the Corsican and Maritime pines (P. nigra laricio and P. pinaster), we first modelled the current and future potential distribution of both pine species in order to use them as habitat variables when modelling the nuthatch distribution. However, the Corsican pine has suffered large distribution losses in the past centuries due to the development of anthropogenic activities, and is now restricted to mountainous woodland. As a consequence, its realized niche is likely significantly smaller than its fundamental niche, so that a projection of the current distribution under future climatic conditions would produce misleading results. To obtain a predicted pine distribution at closest to the geographic projection of the fundamental niche, we used available information on the current pine distribution associated to information on the persistence of isolated natural pine coppices. While common thresholds (maximizing the sum of sensitivity and specificity) predicted a potential large loss of the Corsican Nuthatch distribution by 2100, the use of more appropriate thresholds aiming at getting closer to the fundamental distribution of the Corsican pine predicted that 98% of the current presence points should remain potentially suitable for the nuthatch and its range could be 10% larger in the future. The habitat of the endemic Corsican Nuthatch is therefore more likely threatened by an increasing frequency and intensity of wildfires or anthropogenic activities than by climate change.
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