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.
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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