Looking into the past – the reaction of three grouse species to climate change over the last million years using whole genome sequences

Tracking past population fluctuations can give insight into current levels of genetic variation present within species. Analysing population dynamics over larger timescales can be aligned to known climatic changes to determine the response of species to varying environments. Here, we applied the Pairwise Sequentially Markovian Coalescent (psmc ) model to infer past population dynamics of three widespread grouse species; black grouse, willow grouse and rock ptarmigan. This allowed the tracking of the effective population size (N_e) of all three species beyond 1 Mya, revealing that (i) early Pleistocene cooling (~2.5 Mya) caused an increase in the willow grouse and rock ptarmigan populations, (ii) the mid‐Brunhes event (~430 kya) and following climatic oscillations decreased the N_e of willow grouse and rock ptarmigan, but increased the N_e of black grouse and (iii) all three species reacted differently to the last glacial maximum (LGM) – black grouse increased prior to it, rock ptarmigan experienced a severe bottleneck and willow grouse was maintained at large population size. We postulate that the varying psmc signal throughout the LGM depicts only the local history of the species. Nevertheless, the large population fluctuations in willow grouse and rock ptarmigan indicate that both species are opportunistic breeders while black grouse tracks the climatic changes more slowly and is maintained at lower N_e. Our results highlight the usefulness of the psmc approach in investigating species’ reaction to climate change in the deep past, but also that caution should be taken in drawing general conclusions about the recent past.     

Spring density and summer habitat use of alpine rock ptarmigan Lagopus muta helvetica in the southeastern Alps

In the Alps tourism, land-use practices and climate change may cause a loss of suitable habitat of rock ptarmigan (Lagopus muta helvetica). Hence, there is a need for basic research on population densities and habitat requirements of this species as a basis for long-term monitoring studies. So far, in the Austrian Alps, no accurate data on densities and trends of rock ptarmigan populations are available. We carried out counts of calling cocks in the southeastern part of the Austrian Alps (Nockberge National Park, Carinthia, Austria) between 31 May and 1 July 2003 and evaluated the distribution of male rock ptarmigan territories. The spring density of 5.4 territorial cocks per square kilometre was similar to densities in the Swiss Alps but higher than spring population densities in the Italian Alps and the Pyrenees. To investigate summer habitat use, we established a grid mapping of habitat parameters and rock ptarmigan signs. In total, 38 squares with signs of rock ptarmigan presence were recorded (i.e. 32% of all recorded squares). The presence of rock ptarmigan was significantly correlated with cover of rock and rock ptarmigan preferred habitat patchiness. Our study provides a useful reference for future monitoring of this species in the alpine distribution range considering the potential decrease and fragmentation of alpine habitats resulting from climate change and human impacts.     

Restoring Sage‐grouse nesting habitat through removal of early successional conifer

Conifer woodlands have expanded into sagebrush (Artemisia spp.) ecosystems and degrade habitat for sagebrush obligate species such as the Greater Sage‐grouse (Centrocercus urophasianus). Conifer management is increasing despite a lack of empirical evidence assessing outcomes to grouse and their habitat. Although assessments of vegetation recovery after conifer removal are common, comparisons of successional trends with habitat guidelines or actual data on habitat used by sage‐grouse is lacking. We assessed impacts of conifer encroachment on vegetation characteristics known to be important for sage‐grouse nesting. Using a controlled repeated measures design, we then evaluated vegetation changes for 3 years after conifer removal. We compared these results to data from 356 local sage‐grouse nests, rangewide nesting habitat estimates, and published habitat guidelines. We measured negative effects of conifer cover on many characteristics important for sage‐grouse nesting habitat including percent cover of forbs, grasses, and shrubs, and species richness of forbs and shrubs. In untreated habitat, herbaceous vegetation cover was slightly below the cover at local nest sites, while shrub cover and sagebrush cover were well below cover at the nest sites. Following conifer removal, we measured increases in herbaceous vegetation, primarily grasses, and sagebrush height. Our results indicate that conifer abundance can decrease habitat suitability for nesting sage‐grouse. Additionally, conifer removal can improve habitat suitability for nesting sage‐grouse within 3 years, and trajectories indicate that the habitat may continue to improve in the near future.     

Past and potential future population dynamics of three grouse species using ecological and whole genome coalescent modeling

Studying demographic history of species provides insight into how the past has shaped the current levels of overall biodiversity and genetic composition of species, but also how these species may react to future perturbations. Here we investigated the demographic history of the willow grouse (Lagopus lagopus), rock ptarmigan (Lagopus muta), and black grouse (Tetrao tetrix) through the Late Pleistocene using two complementary methods and whole genome data. Species distribution modeling (SDM) allowed us to estimate the total range size during the Last Interglacial (LIG) and Last Glacial Maximum (LGM) as well as to indicate potential population subdivisions. Pairwise Sequentially Markovian Coalescent (PSMC) allowed us to assess fluctuations in effective population size across the same period. Additionally, we used SDM to forecast the effect of future climate change on the three species over the next 50 years. We found that SDM predicts the largest range size for the cold‐adapted willow grouse and rock ptarmigan during the LGM. PSMC captured intraspecific population dynamics within the last glacial period, such that the willow grouse and rock ptarmigan showed multiple bottlenecks signifying recolonization events following the termination of the LGM. We also see signals of population subdivision during the last glacial period in the black grouse, but more data are needed to strengthen this hypothesis. All three species are likely to experience range contractions under future warming, with the strongest effect on willow grouse and rock ptarmigan due to their limited potential for northward expansion. Overall, by combining these two modeling approaches, we have provided a multifaceted examination of the biogeography of these species and how they have responded to climate change in the past. These results help us understand how cold‐adapted species may respond to future climate changes.     

张广才岭藏獾洞穴生境选择

2008年9月至2009年8月,在黑龙江省方正林业局新风林场,用不定宽样线法对藏獾洞穴生境选择进行研究,共记录了55组藏獾洞穴,藏獾洞口平均直径为(27.40±7.15)cm,洞深平均为(84.18±22.04)cm,倾角平均为(26.36±9.10)°,洞口总数=3.02个常用洞数+0.80个不常用洞数+0.56个废弃洞数。相对于对照样方而言,藏獾洞穴更偏爱选择位于郁闭度和植被盖度小,灌木密度大、距离近,乔木距离远,距水源和农田近、人为干扰距离远,坡度较缓的向阳中坡位的生境。资源选择函数模型为:logit(p)=246.980-1.059×植被盖度-0.703×距水源距离-1.403×坡度-45.005×坡向,模型的正确预测率为93.9%。     

Spacing behaviour and habitat use of rock ptarmigan (Lagopus mutus) at low density in the Italian Alps

Studies of rock ptarmigan Lagopus mutus in northern latitudes have shown that, in the breeding season, the majority of cocks pair monogamously and defend small territories, whilst in most populations, a small proportion of cocks are polygynous or remain unmated. Little is known, however, on spacing behaviour and habitat use of alpine rock ptarmigan populations occurring at low densities at the southern edge of the species’ range. From 1995 to 1997, we trapped, radio-tracked and observed birds in the Central Italian Alps (elevation 2,000–3,000 m) in order to investigate spacing behaviour and habitat use in alpine landscapes where habitats offering rich food and cover are patchy. Both sexes were selective in their habitat use, and cocks did not establish territories on bare ground, artificial or nutrient rich grasslands or bogs. In the breeding season, cocks had larger home ranges than hens (cocks 99 ± 57 ha, hens 50 ± 25 ha) that overlapped with the ranges of neighbouring cocks and hens. Cocks were monogamous and defended relatively large territories (core areas of home ranges: cocks 37 ± 26 ha, hens 24 ± 12 ha), which corresponded with low spring densities (0.47–2.29 cocks km⁻² and 0.35–1.60 pairs km⁻²). Territory size of individual cocks was negatively correlated with the amount of high quality habitat in the core-area. Our results suggest increased home ranges and large breeding territories in low density alpine rock ptarmigan populations, compared to populations occurring at higher densities in the central and northern alps, and on subarctic and arctic grounds at northern latitudes, confirming the predictions of models on food-based territoriality.     

Spatio-temporal patterns of ptarmigan occupancy relative to shrub cover in the Arctic

Rock and willow ptarmigan are abundant herbivores that require shrub habitats in arctic and alpine areas. Shrub expansion is likely to increase winter habitat availability for ptarmigan, which in turn influence shrub architecture and growth through browsing. Despite their ecological role in the Arctic, the distribution and movement patterns of ptarmigan are not well known, particularly in northern Alaska where shrub expansion is occurring. We used multi-season occupancy models to test whether ptarmigan occupancy varied within and among years, and the degree to which colonization and extinction probabilities were related to shrub cover and latitude. Aerial surveys were conducted from March to May in 2011 and April to May 2012 in a 21,230 km² area in northeastern Alaska. In areas with at least 30 % shrub cover, the probability of colonization by ptarmigan was >0.90, indicating that moderate to extensive patches of shrubs (typically associated with riparian areas) had a high probability of becoming occupied by ptarmigan. Occupancy increased throughout the spring in both years, providing evidence that ptarmigan migrated from southern wintering areas to breeding areas north of the Brooks Range. Occupancy was higher in the moderate snow year than the high snow year, and this was likely due to higher shrub cover in the moderate snow year. Ptarmigan distribution and migration in the Arctic are linked to expanding shrub communities on a wide geographic scale, and these relationships may be shaping ptarmigan population dynamics, as well as rates and patterns of shrub expansion.     

Capturing cross-scalar variation of habitat selection with grid sampling: an example with hazel grouse (Tetrastes bonasia L.)

The objective of this study was to investigate a grid-based sampling design to determine the cross-scalar selection of habitat by a territorial animal species: the hazel grouse (Tetrastes bonasia L.). In each of three sites with increasing hazel grouse nest site density, three lattice grids were used to measure both the habitat variables and the species occurrence in 100 30?×?30 m cells. We calculated the average values for habitat variables, as well as use versus non-use by the species, at three spatial scales: small (1?×?1 cell), intermediate (2?×?2 cells) and large (3?×?3 cells). Generalised linear mixed models were integrated into a method of variation and hierarchical partitioning and used to assess the relationship between the habitat variables and the species preferences at each scale. In all scales, species selection was associated with ground layer composition. Selection was also associated with the composition of the woody layer and negatively associated with dominance of tor grass (Brachypodium rupestre (Host) Roem. & Schult.) at the two larger scales. Both litter cover and thinning contributed positively to the habitat selection at the two smaller scales. The other variables were significant only at one scale or explained a relatively low proportion of the variation at multiple scales. Neither the management nor the stand structure variables played a significant independent role across scales when compared with ground layer variables. The total variation explained was highest (ca. 90 %) at the large scale. This finding indicates the possibility of obtaining cross-scalar hazel grouse preferences from grid-based sampling, provided that spatial autocorrelation in the data is handled appropriately.     

Temporal dynamics of grouse populations at the southern edge of their distribution

Studies of grouse conducted at northern latitudes have shown that tetraonids frequently exhibit cyclic fluctuations in abundance but little is known about the dynamics of grouse species at the southerly edge of their range. Hunting statistics from four species of grouse based on 30 yr of data collected from 210 hunting areas were examined from the Dolomitic Alps in the province of Trentino. These data were summed to represent 18 time series from discrete mountain groups. Analyses identified cycles of ca 5 yr in the minority of rock ptarmigan Lagopus mutus and hazel grouse Bonasa bonasia populations. These cycles only showed significant negative autocorrelation at half the cycle period and were classified as phase-forgetting quasi-cycles. Cycles were not found in time series of black grouse Tetrao terix or capereaillie Tetrao urogallus. Correcting time series for hunting effort or hunting restrictions tended to increase the proportion of populations that exhibited cycles but no difference in the strength of second order density dependence, A linear first order density-dependent autoregressive model described the dynamics of most of the populations with the exception of a proportion of rock ptarmigan and black grouse populations where a non linear first order model provided the best tit. We compare the findings with studies conducted in Finland and suggest possible reasons for the reduced tendency to cycle in the populations of southern Europe.     

Broad-scale habitat use by red-legged partridge <Emphasis Type="Italic">(Alectoris rufa</Emphasis>) in a low-density area in northwestern Spain

We developed broad-scale habitat selection models for the distribution of red-legged partridge Alectoris rufa in a low-density area in northwestern Spain, the Baixa-Limia site of community importance (SCI). The fieldwork consisted of ground surveys in 1 × 1 km squares. For habitat selection analysis, we used a 2 × 2 km grid integrating the information obtained in the 1 × 1 km squares. As predictors we used environmental variables measured on digital 1:50,000 scale cartography using a geographical information system (GIS). The red-legged partridge was scarce in the study area. The logistic regression analysis carried out on data from the squares with probable and confirmed breeding included the area of scrubland and pastureland with a positive sign. Using the breeding index category (BIC) three variables produced a slightly positive response: area of scrubland and pastureland, length of border between scrublands and forests, and length of border between forests and dams. The difficulty for modelling the habitat selection of this species could be due to human activities (hunting, habitat loss, restocking of hunt species), and may have modified their habitat preferences. Furthermore, the occupation of suboptimal habitats would distort the real habitat preferences.     

Fine-Scale Habitat Selection by Breeding White-Tailed Ptarmigan in Colorado

Species distributions are influenced by climate and topography in alpine ecosystems, yet resource selection studies of alpine species are uncommon. Basic characteristics of habitats used by alpine-endemic white-tailed ptarmigan (Lagopus leucura) have been described to explain foraging behavior, morphology, and survival in many alpine regions; however, there is a lack of information about fine-scale habitat selection for nesting and brood-rearing, particularly in the southern extent of the species’ range. Few studies have tested whether nest and brood-site selection by white-tailed ptarmigan are influenced by fine-scale components such as vegetation and arthropod communities. We assessed these fine-scale habitat characteristics analyzing paired use-available resource selection for nest (n = 61) and brood (n = 54) sites. We used conditional logistic regression for data collected in 2 alpine areas along the Front Range of Colorado, USA, during 2014 and 2015. We evaluated resource selection at larger (patch) and finer (nest site) scales. Nest-site selection at the patch scale was best predicted by cover (%) of forage forbs, rock and gravel, and shrubs. Forage forb cover explained more variation in our top nest model at the patch scale when compared to models with specific vegetation species. Females placed their nests along elevational gradients but more so at lower elevations and selected for less graminoid cover at the nest-site scale. Brood habitat selection at the patch level was influenced by cover (%) of rock and gravel and proximity to shrubs (m). Analysis of a subset of our brood data (n = 34) revealed females selected brood habitat that contained high arthropod abundance (e.g., Cicadellidae) over high vegetation cover, likely as a response to meet dietary requirements of chicks. Our results demonstrate how and where white-tailed ptarmigan are currently selecting these different breeding sites in Colorado's alpine, giving us insight into consequences this alpine-endemic bird may face if their breeding habitat is altered. © 2019 The Wildlife Society.     

Feeding habitats of blue sheep (Pseudois nayaur) during winter and spring in Helan Mountains, China

The feeding habitat selection of blue sheep (Pseudois nayaur) was studied by direct observation method in the Helan Mountains, China during winter (from November to December) and spring (from April to June) from 2003 to 2004. We established 25 line transects to collect information on feeding habitats used by blue sheep. Blue sheep in the study area preferred mountain savanna forests, a habitat dominated by Ulmus glaucescens, with medium tree density (<4 individuals / 400 m²), moderate tree height (4–6 m), higher shrub density (> 5 individuals / 100 m²), higher shrub (> 1.3 m), higher food abundance (> 50 g), moderate distance to human disturbance (< 500 m), and mild distance to bare rock (< 2 m). Such habitats characterized by 12 ecological factors were preferred as feeding areas by blue sheep during winter. Similar to habitat selection by the species during winter, blue sheep also showed a preference for mountain savanna with tree dominated by Ulmus glaucescens and medium tree density (< 4 individuals / 400 m²) during spring. Nevertheless, blue sheep preferred medium tree height (< 6 m), moderate tree density (5–10 individuals / 100 m²), medium shrub height (1.3–1.7 m), higher food abundance (> 100 g), moderate altitude (< 2 000 m), moderate distance to water resource (< 500 m), and medium hiding cover (50%–75%) during spring. Selection of the feeding habitats by sheep showed a significant difference in vegetation type, landform feature, dominant tree, tree height, shrub density, distance to the nearest shrub, food abundance, slope direction, slope degree, distance to water resource, and hiding cover between winter and spring. Results of principal components analysis indicated that the first principal component accounted for 24.493% of the total variance among feeding habitat variance during winter, with higher loadings for vegetation type, dominant tree, tree height, distance to the nearest tree, shrub density, shrub height, altitude, distance to water resource, and distance to human disturbance. In spring, the first principal components explained 28.777% of the variance, with higher loadings for vegetation type, distance to the nearest tree, shrub height, distance to the nearest shrub, food abundance, altitude, and distance to human disturbance. Translated from Zoological Research, 2005, 26(6): 580–589 [译自: 动物学研究]     

Ruffed Grouse Brood Habitat Use in Mixed Softwood-Hardwood Nordic-Temperate Forests,Quebec, Canada

Abstract: Adequate cover is a critical component of ruffed grouse (Bonasa umbellus) habitat during the brood-rearing period when chick mortality is high. We assessed habitat use by ruffed grouse during the brood-rearing period by comparing characteristics of tree, shrub, and ground layers at ruffed grouse brood and random locations. We captured and radiomarked 29 females with broods in 2 forest settings of the Réserve faunique de Portneuf, Quebec, Canada. We described grouse habitat using ground surveys and forest maps, and we identified the used habitat characteristics using analysis of variance and logistic regression. Females with broods used mixed and regenerated clearcut stands that were 1.5–7 m tall and 11–20 years old. Compared with random locations, grouse locations had higher lateral obstruction (76% vs. 68%), higher small-stem density (29,085 stems/ha vs. 19,340 stems/ha), and were closer to roads and trails. Percentage of coverage by ground vegetation was not higher at grouse locations as often reported in previous studies. Results from this study will help orient ruffed grouse habitat management on Quebec public land and elsewhere in nordic—temperate mixed hardwood—softwood forests to maintain suitable brood habitat after logging operations. Forest management should promote growth of young mixed stands with high horizontal and vertical cover provided by high small-stem density, which offers protection against aerial and terrestrial predation. Edges such as roadsides are also important in brood habitat as they provide food and cover.     

Temperature can interact with landscape factors to affect songbird productivity

Increased temperatures and more extreme weather patterns associated with global climate change can interact with other factors that regulate animal populations, but many climate change studies do not incorporate other threats to wildlife in their analyses. We used 20 years of nest‐monitoring data from study sites across a gradient of habitat fragmentation in Missouri, USA, to investigate the relative influence of weather variables (temperature and precipitation) and landscape factors (forest cover and edge density) on the number of young produced per nest attempt (i.e., productivity) for three species of songbirds. We detected a strong forest cover × temperature interaction for the Acadian Flycatcher (Empidonax virescens) on productivity. Greater forest cover resulted in greater productivity because of reduced brood parasitism and increased nest survival, whereas greater temperatures reduced productivity in highly forested landscapes because of increased nest predation but had no effect in less forested landscapes. The Indigo Bunting (Passerina cyanea) exhibited a similar pattern, albeit with a marginal forest cover × temperature interaction. By contrast, productivity of the Northern Cardinal (Cardinalis cardinalis) was not influenced by landscape effects or temperature. Our results highlight a potential difficulty of managing wildlife in response to global change such as habitat fragmentation and climate warming, as the habitat associated with the greatest productivity for flycatchers was also that most negatively influenced by high temperatures. The influence of high temperatures on nest predation (and therefore, nest predators) underscores the need to acknowledge the potential complexity of species' responses to climate change by incorporating a more thorough consideration of community ecology in the development of models of climate impacts on wildlife.     

大兴安岭驯鹿(Rangifer tarandus)的春季生境选择

为确定分布于我国大兴安岭西北麓的濒危驯鹿(Rangifer tarandus)的春季生境选择特征,于2012和2013年的3—4月间,采用样线样方结合的生境调查方法,对内蒙根河驯鹿的春季偏好生境和对照生境进行了取样,并对样方的海拔和乔木郁闭度等23个生境变量进行了计测与分析。结果表明:与非利用样方(n=132)相比,驯鹿春季偏好生境(n=79)的海拔((957.27±1.68)m)、乔木郁闭度((32.84±2.72)%)、乔木密度(21.72±1.52)、地表植被盖度((85.06±1.03)%)、树桩数(6.81±0.45)和倒木数(5.73±0.54)均显著较大(Mann-Whitney U test,P0.05),而灌木盖度((57.95±2.79)%)、枯草盖度((33.11±2.79)%)、乔木高度((9.58±0.27)m)和灌木均高((59.85±2.69)cm)显著较小(Mann-Whitney U test,P0.05),而且驯鹿春季趋向于选择西坡和南坡(77.21%)的坡度较缓(93.67%)、位于坡中下位(67.09%)的生境,并偏好选择针叶林(68.35%)中的隐蔽度好(82.28%)、避风状况良好(64.56%)、湿润(60.76%)、距水源较近(≤1000 m,94.94%)及距人为干扰较远(≥1000m,87.34%)的生境(Chi-Square test,P0.05)。此外,驯鹿偏好生境的变量主成分分析结果表明,坡位、乔木特征(乔木胸径和乔木高度)、食物多度(灌木盖度、倒木数及树桩数)、雪被特征(雪深、雪盖度和郁闭度)、干扰强度(距人为干扰距离)、植被类型(坡向和植被类型)是影响驯鹿春季生境选择的重要因素,综合体现了驯鹿在春季对保温、食物和安全性的需求。     

Modelling habitat use of Tetrao urogallus L. in Austria for conservation issues

Loss and deterioration of habitats are major threats for Tetrao urogallus in central Europe, where forests are highly fragmented and forest practices have distinctly changed during the last decades. Habitat models are important tools for conservation planning, often relying on presence–absence data. We mapped indirect signs of Tetrao urogallus presence as well as habitat variables over a series of seven study areas in the Austrian Alps, situated on limestone and on silicate rock. We modelled habitat use of Tetrao urogallus with one parametric approach (binary logistic regression) and two machine learning classification algorithms (classification trees and random forests) for both geological substrata separately. All three modelling approaches performed equally well in terms of accuracy or predictive power, but differed in model calibration. Three variables significantly contributed to all three habitat models on limestone and on silicate substrate, respectively, i.e. the cover of field-layer, the cover of dwarf shrubs and the proportion of deciduous trees in forest stands on limestone and the cover of field-layer, the canopy cover and the occurrence of Abies alba and/or Pinus sylvestris in forest stands on silicate rock. Some variables like the cover of Rubus sp. appeared in several models, which are not frequently mentioned in other studies. There have been some explanatory variables, which would have been missed, when applying just one single modelling approach, for example the occurrence of forest edges, the availability of canopy gaps and the supply of ant hills. Our results suggest differing habitat management strategies on limestone and on silicate rock. Considering the large spatial requirements of Tetrao urogallus the necessity of active habitat management for Tetrao urogallus becomes obvious.     

贺兰山马鹿冬季取食和卧息生境选择

2007 年12 月至2008 年1 月,在贺兰山地区,利用痕迹检验法和直接观察法对马鹿阿拉善亚种的冬季取食和卧息生境选择进行研究。通过在选定的15 条沟段里进行调查,共测定了72 个取食利用样方,59 个卧息利用样方和131 个对照样方的18 种生态因子。结果表明,马鹿在冬季偏好的取食地为平滑起伏坡,以酸枣、柳为优势乔木、混合型树林或空地,乔木高大稀疏、间距较远,灌木密度大,草本盖度较高,位于< 15°的半阴半阳坡的下坡位,距裸岩远,隐蔽度高;偏好的卧息地在山地疏林草原带的平滑起伏坡上,以酸枣、柳为优势乔木、混合型树林或空地,乔木高大稀疏,灌木矮小、稀疏且距离较远,草本盖度较高,位于< 15°阳坡的下坡位,远离裸岩,隐蔽程度高。马鹿冬季的取食和卧息生境在草本盖度和隐蔽度上差异极显著。相对于卧息生境,马鹿冬季的取食生境对草本盖度和隐蔽度要求更低一些。马鹿冬季取食地的资源选择函数为1.155 - 0.149 × 乔木高度- 0.066 × 草本盖度+ 0.190 × 坡度,模型的正确判别率为86.8% ;马鹿冬季卧息地的资源选择函数为- 30.936
+ 0.494 × 乔木高度+ 0.257 × 坡度-0.002 × 海拔高度+ 0.387 × 隐蔽度,模型的正确判别率为95.8% 。食物、隐蔽条件以及贺兰山的独特地形特征是影响马鹿冬季取食和卧息生境选择的主要因素。     

House sparrow (Passer domesticus) habitat use in urbanized landscapes

The house sparrow (Passer domesticus) is showing population declines in many parts of Europe, with recent declines being particularly severe in urban areas. To date, relatively little is known about the species’ habitat associations within urbanized landscapes. We report here an investigation of the habitat associations of house sparrows using a survey of 1223 stratified randomly selected 500 × 500-m squares within urbanized landscapes of the UK, defined as at least 25% ‘human cover’. The densities of chirping male house sparrows and of all house sparrows were analysed separately to obtain insights into breeding habitat requirements and general habitat associations, respectively. Multi-model inference showed that residential areas (houses, flats), allotments (areas used for small-scale horticulture) and farm buildings were key predictors of house sparrow density and chirping male density. Separate analyses on landscapes of differing human cover showed similar results. Within residential areas, the increase of house sparrow density with habitat area (on a log scale) was approximately threefold greater when private gardens were present than when they were absent. The model predicted a rapid decline in house sparrow abundance when only a small area of private gardens is converted to continuous housing. Allotments and residential areas with gardens are likely to be under pressure due to increased demand for housing, specifically from the infilling of green space within urban areas. It would seem to be imperative that any action plan to protect urban house sparrow populations should include specific protection of such key habitats. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Population genetic structure of rock ptarmigan in the 'sky islands' of French Pyrenees: implications for conservation

Expected consequences of global warming include habitat reduction in many cool climate species. Rock ptarmigan is a Holarctic grouse that inhabits arctic and alpine tundra. In Europe, the Pyrenean ptarmigan inhabits the southern edge of the species' range and since the last glacial maximum its habitat has been severely fragmented and is restricted to high-alpine zones or 'sky islands'. A recent study of rock ptarmigan population genetic in Europe found that the Pyrenean ptarmigan had very low genetic diversity compared with that found in the Alps and Scandinavia. Habitat fragmentation and reduced genetic diversity raises concerns about the viability of ptarmigan populations in the Pyrenees. However, information on population structuring and gene flow across the Pyrenees, which is essential for designing a sound management plan, is absent. In this study, we use seven microsatellites and mitochondrial control region sequences to investigate genetic variation and differentiation among five localities across the Pyrenees. Our analyses reveal the presence of genetic differentiation among all five localities and a significant isolation-by-distance effect that is likely the result of short dispersal distances and high natal and breeding philopatry of Pyrenean ptarmigan coupled with severe habitat fragmentation. Furthermore, analysis of molecular variance, principal component analysis and Bayesian analysis of genetic structuring identified the greatest amount of differentiation between the eastern and main parts of the Pyrenean chain separated by the Sègre Valley. Our data also show that the Canigou massif may host an isolated population and requires special conservation attention. We propose a management plan which includes the translocation of birds. If a sky island structure affects genetic divergence in rock ptarmigan, it may also affect the genetic structure of other sky island species having low dispersal abilities.     

Nest-site selection of the White Eared pheasant in southwestern Sichuan Province, China

From April to July 2003 and 2004, we surveyed the nest-site selection of the White Eared pheasant (Crossoptilon crossoptilon) in the Zhujie Monastery and in the mountain facing it in Sichuan Province, China. In this paper, we studied the nest characteristics and the clutch size of the pheasant. Habitat sampling method was used to determine the variables that might affect the nest-site selection of the White Eared pheasant. Chi-square test was used to identify which habitat type was likely to be preferred by the bird. Independent-samples t test and Mann-Whitney U test were used to find which variables were important for the birds’ nest-site selection. A total of 13 nests were found. Oak shrub was greatly preferred as nest sites (84.62%). Nests under a rock wall (7.69%) and a fallen tree (7.69%) were also found. The average clutch size of a White Eared pheasant is 7.33±0.54 (range, 5–11; n=12). Laying period was between April 27 and May 21. In the Zhujie area, 1 nest was in the forest and 11 nests were in oak shrubs. The species preferred oak shrub as its nesting habitat (χ ²=8.333, df=1, P<0.05). The bird was more likely to place its nest in sites with a high coverage, i.e. 0.5, 1, and 2 m above the ground (independent-samples t test, P<0.05), and with a large shrub diameter (Mann-Whitney U test, P<0.05). The species are more likely to prefer sites with plant cover, shrub cover (independent-samples t test, P<0.05), and shrub height (Mann-Whitney U test, P<0.05) in a relatively small range. Translated from Journal of Beijing Normal University (Natural Science), 2005, 41(2) (in Chinese)