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1.
Oliver Krüger 《Bird Study》2013,60(2):125-132
Capsule Variation in reproduction between territories was strongly influenced by intra- and interspecific competition, phenotype, levels of rainfall and human disturbance.

Aims To assess the relative importance of competition, food, habitat quality, weather and phenotype as predictors of variation in reproduction in Buzzard.

Methods Annual breeding data were collected from 1989 to 1996 in a 300-km2 study area and related to 35 independent variables through multivariate regression models.

Results Significant predictors of variation in reproduction between territories (78% variance explained) were variables describing intra- and interspecific competition, plumage morph, laying date, precipitation levels and anthropogenic disturbances in the breeding territory. Competition and plumage morph seem to be particularly important, as these variables explained a high level of variation (81%) in the 1996 reproduction of this population.

Conclusion The potential importance of competition, plumage morph and precipitation for reproduction in this Buzzard population is emphasized.  相似文献   

2.
F. Henrioux 《Bird Study》2013,60(3):250-257
Capsules Sites are selected as part of an antipredator strategy.

Aims To assess if site choice depends on habitat variables at nest sites and if habitat quality influences reproduction.

Methods Breeding density was explored in northwestern Switzerland from 1992 to 1996. Habitat variables were examined at 38 breeding sites and were compared with data collected from random sites. Habitat quality was estimated using the discriminant function scores of the nesting sites.

Results Breeding density was found to vary between years; more pairs bred and raised more young in 1993, a year of high vole abundance. Long-eared Owls tended to avoid the vicinity of buildings; they occupied sites with denser forest edges, greater canopy cover, and with more conifers than random sites. I found no statistical evidence that they used less optimal sites when the population was high. The number of fledglings increased with habitat quality, but did not vary with any of the habitat variables taken separately.

Conclusion Long-eared Owl selects nesting habitat as part of an anti-predator strategy, but the measures of territory quality did not seem to be a limiting factor for the population.  相似文献   

3.
Capsule: Black Grouse population increases were greatest where new native woodland (NNW) within 1500?m of leks comprised approximately 30% of land area and averaged 5 years old.

Aims: To examine whether change in a population of Black Grouse Lyrurus tetrix in Scotland was associated with the creation of native woodland.

Methods: We examined whether lek location, size and change in size were associated with habitat and topography surrounding leks. We also examined vegetation differences in NNW and adjacent unplanted moorland.

Results: From 2002 to 2012 the number of lekking male Black Grouse increased by 90%. Lek occurrence was positively associated with the amount of NNW edge habitat. Leks were larger where there was more adjacent NNW. Lek increases were greatest where NNW plots comprised approximately 30% land area, and were 5 years old, within a 1500?m radius. Plots aged more than approximately 20 years old were associated with Black Grouse population declines. NNW supported taller and denser important field-layer vegetation than adjacent moorland, likely due to grazing exclusion.

Conclusions: Subject to longer-term management commitments to stimulate continued regrowth of the important field layer and maintain benefits for Black Grouse, expansion of native woodland could contribute to landscape-scale recovery of Black Grouse after decades of decline.  相似文献   

4.
《Plains anthropologist》2013,58(94):43-48
Abstract

During the 1920's, W.H. Over and M.W. Stirling excavated skeletal material from cemeteries at the Mobridge site. Their records are not clear as to the exact location of burial recovery. Mobridge has at least three distinct burial areas (Features 1, 2, and 3), and there are craniometric and temporal differences among them. A comparison of crania from Features 1, 2, and 3 with the Over and Stirling samples gives some insight as to the location of their burials. Burials excavated by Over classify primarily with Feature 2, indicating this to be their point of origin. A few burials from Feature 1 also appear to be represented. Stirling's sample groups with areas 1 and 3. His sample possibly originated there, although it seems more likely that they came from a location north of the village which dates to the same time period as Features 1 and 3 and represents the same population.  相似文献   

5.
Capsule Careful management is required to maintain or create habitats with the correct proportions of rush with reeds that are preferred by this subspecies.

Aims To determine the habitat requirements of Eastern Iberian (Western Iberian Reed Buntings were not included in the study) Reed Buntings Emberiza schoeniclus witherbyi, a subspecies endemic to a few marshes in France, Spain and Morocco, with a population of 254–360 breeding pairs.

Methods Twenty-five wetlands in Spain were surveyed and presence/absence of Iberian Reed Buntings was deteremined together with data on 41 environmental variables. The relationships between the birds and habitat data were investigated using glm.

Results Proportion of rush with reeds, proportion of reed–bulrush patches and perimeter length of rush–reed patches, were the variables that primarily explained the present distribution of Eastern Iberian Reed Buntings. Other vegetation classes traditionally associated with the presence of the Eastern Iberian Reed Buntings, such as sedges, were not found to be important in the selected models.

Conclusion Conservation planning and management guidelines for this subspecies should focus on encouraging these specific-vegetation parameters. Flood control and grazing are proposed as the best practices that will favour these vegetation variables and avoid simplification of the plant community.  相似文献   

6.
Capsule Although subject to human disturbance Turtle Doves do nest successfully in these olive and orange orchards.

Aim To investigate the breeding ecology of Turtle Doves in a man‐made agricultural habitat in central Morocco.

Methods Turtle Dove nests were monitored in orange and olive orchards over three years (2006, 2007 and 2008). Nest abundance, nest location, egg‐laying chronology, clutch size, nest survival rates and breeding success were determined and compared between orchard types.

Results The Moroccan population of Turtle Doves start breeding earlier than European populations. Clutch size, nest survival rates and breeding success were similar in orange and olive orchards. Nest location differed between orange and olive trees. Nest densities were 16 nests/ha in olive orchards and 45 nests/ha in orange orchards. Nest success rate averaged 48%. Daily nest survival rates did not vary according to orchard types, year and date. In the two orchards, no nest position variables were significant predictors of nesting success.

Conclusion Although highly frequented by people, fruit orchards seem to be suitable breeding habitats for Turtle Doves in this region.  相似文献   

7.
M. J. Goodacre 《Bird Study》2013,60(2):111-113
Capsule Large‐scale intensification of agricultural management during the past 50 years has resulted in a reduction of invertebrate abundance and higher and denser ground vegetation. Food availability for insectivorous birds foraging on the ground has been negatively affected, but the interactions between birds and their food availability are complex and often species‐specific. Populations of Wrynecks Jynx torquilla are declining all over Europe, possibly because of reduced accessibility to their main prey, ground‐dwelling ants, due to higher and denser ground vegetation. However, it is not clear which ground vegetation structures are tolerated by foraging Wrynecks and which habitats are preferred.

Aims To identify the optimal ground vegetation structure and the main habitat types in which Wrynecks search for food.

Method We radiotracked seven Wrynecks in high‐intensity farmland in Switzerland to study foraging habitat use during the reproduction season. Several habitat variables were mapped at each foraging location and compared with locations selected randomly within individual home ranges.

Results Wrynecks preferentially foraged at places with ≥50% bare ground. Vegetation height was not important. Older fruit tree plantations and fallow land were the preferred foraging habitats.

Conclusion Conservation measures should concentrate on preserving semi‐open agricultural landscape matrices with loose ground vegetation cover to provide suitable foraging conditions. This can be achieved even in intensively managed farmland as illustrated in this study.  相似文献   

8.
ABSTRACT

Capsule: Duration and peak frequency of Wren Troglodytes troglodytes songs differ between Welsh islands (Skokholm, Flat Holm, and Sully Island) and a mainland site, suggesting random or cultural divergence.

Aims: The study tests for differences in bioacoustic traits in Wren song between four breeding sites.

Methods: Songs from breeding male Wrens were recorded from three Welsh islands and a representative location on the local mainland. Each sonogram was measured for six variables from the whole song and two distinct phrases from the beginning and middle. The variables were measured manually using an open source acoustic tool and compared between sites using generalized linear mixed-effects models.

Results: There was significant variation in song variables between island sites and the mainland. Skokholm Wren songs were significantly longer in duration than all other sites by up to 66%. Peak frequency was significantly different across all sites with Sully Island having the highest peak frequency and Skokholm the lowest.

Conclusion: The differences in song duration and frequency do not directly suggest a trend associated with selective pressures such as habitat or noise, but instead may be explained by non-selective drivers such as cultural drift or local dialect formation.  相似文献   

9.
Abstract

Basic demographic data of landless and landed peasants from the highlands and valley of Northern Potosi, Bolivia, are compared. Household size and crude birth rates are larger in the highlands than in the valley. Within the highland population, no statistically significant difference was observed between the age‐specific fertility of landless and landed women, nor in the survivorship ratio of their offspring. The prevalence of exchange and reciprocity at the village level may be responsible for the absence of important differences in the fertility and mortality patterns of the landed and landless.  相似文献   

10.
《Plains anthropologist》2013,58(59):227-232
Abstract

The 18th century German agrarian village system has persisted on the plains of western Kansas as a consequence of a Roman Catholic centered social system. The acculturation process has been retarded by the centripetal forces of church, village, and kinship identities.  相似文献   

11.
《Plains anthropologist》2013,58(82):289-300
Abstract

The controlled analysis of the effects of natural resource management techniques on cultural resources has rarely been undertaken. Scarification is used by timber managers to mix soil and seed to insure proper regeneration in harvested areas. The effects of one scarification project on an artificial “site” are described and the resultant disturbance evaluated in light of its potential to affect cultural resources. Suggestions for meeting timber management goals while minimizing impacts on cultural resources are offered.  相似文献   

12.
Abstract

Old-growth forests in south eastern Australia are important for biodiversity conservation, recreation, carbon storage, social values and, to a declining extent, for timber production. Developing a comprehensive definition of old-growth forest that can apply across all Australian vegetation types has been challenging. Old growth can be viewed from ecological and social perspectives. For policy and management purposes old growth has been defined as a growth stage in forest development, incorporating ecological maturity and lack of evidence of past disturbance. Classification and assessment of old growth has largely been restricted to those areas covered by regional forest agreements (RFAs) between different states and the Federal Government. Old growth can be impacted by wildfire, timber harvesting, insect pests, diseases and other disturbances. Climate change will also present challenges for the future management of old-growth forests. There is increasing scientific understanding of the relationships between species, forest growth stage and old-growth forest attributes. To meet biodiversity conservation objectives, the management focus is shifting from assessing and protecting old-growth forests, to providing for forests across the landscape with old-growth attributes. This approach may be at odds with other conceptions of old growth based on notions of undisturbed systems free of human influence.  相似文献   

13.
Capsule: Habitat structure and composition explained spatial variation in breeding distribution and nesting success in a declining upland Eurasian Curlew Numenius arquata population in North Wales.

Aims: To identify environmental correlates of Curlew breeding distribution, nesting success and change in distribution.

Methods: Thirty random 1?km squares stratified by historical population trend were surveyed for Curlew density and nesting success, and habitat- and predation-related variables in a landscape containing agriculturally improved farmland, and moorland that was partly protected and subject to grazing reductions for nature conservation. Analyses tested for associations between Curlew measures and environmental variables.

Results: Curlew breeding density declined by 29% between 1994 and 2008, and was highest in squares comprising a mixture of moorland and agriculturally improved farmland, and in squares with lower vegetation density and higher cover of Nardus stricta (characteristic of rough grazing). Nesting success was positively associated with cover of Trichophorum germanicum (characteristic of mire). Vegetation density was lower than average in squares with the highest Curlew densities, while in the protected area vegetation density was higher than average.

Conclusion: Habitat and vegetation variables influenced Curlew distribution and nesting success in North Wales, largely in line with previous results but with no evidence for predator-related influences. Habitat condition for Curlew in the protected area could probably be increased through targeted increases in grazing alongside the protection of priority habitats.  相似文献   

14.
Capsule Set-aside schemes have allowed breeding Woodlarks to colonize farmland, but heathland and forestry habitats remain the stronghold.

Aims To determine which habitats provide the best conditions for breeding Woodlarks and whether a buffer effect is operating, with density increasing faster in the poorer quality habitat as the population grows.

Methods Habitat colonization was examined and breeding success compared among heathland, clear-felled and young conifer plantations, and farmland set-aside.

Results Woodlarks on heathland and forestry habitats had similar clutch sizes and nesting success, but clutch sizes may be lower on farmland. Heathland was recolonized when population density was low in forest habitats, while farmland was colonized when density was increasing, and areas close to forest were preferentially occupied. Woodlarks breeding on farmland preferred set-aside stubbles to other field types.

Conclusion Forestry and heathland habitats are similar in quality for breeding Woodlarks, with no evidence for a buffer effect. Farmland set-aside may be suboptimal but the area available is much greater than the area of forest or heathland, and could therefore make a significant contribution to the conservation of the Woodlark population. However, set-aside should not be seen as an alternative to the conservation of forest and heathland.  相似文献   

15.
Capsule Daylength, rather than latitude, was found to be an important determinant of variation in clutch size.

Aims To describe the nature of spatial and temporal variation in clutch size, and explore the ecological correlates of these patterns.

Methods We tested the prediction that seasonal declines in clutch size will be greater at higher latitudes. The environmental variables focused on were the influence of daylength, plant productivity, seasonality (i.e. Ashmole's hypothesis) and physiological mechanisms that relate clutch size to ambient temperature. We used data from 1980 to 2003 on spatial variation in clutch size across Britain for single‐brooded species, in which clutch size can be taken as a measure of annual reproductive investment. We included all seven species, from five families, with sufficient data in the British Trust for Ornithology's Nest Record Scheme.

Results There are strong seasonal declines in clutch size but little evidence for latitudinal gradients in clutch size or in latitudinal gradients in the rate of seasonal clutch size decline. Of the environmental variables investigated, daylength had the most marked effect on clutch size; this was positive in diurnal species and negative in the one nocturnal species.

Conclusions Although this study was confined to a relatively small latitudinal range of 8°, we found marked latitudinal gradients in a number of factors thought to drive spatial patterns in clutch size. Moreover, such variation is of sufficient magnitude to generate spatial patterns in other ecological variables in Britain. There is thus no simple explanation for the lack of a latitudinal gradient in clutch size. The results concerning daylength indicate that the time available for foraging is an important determinant of variation in clutch size.  相似文献   

16.
Abstract

Feral goats and hares were commonly infested by immature stages of the New Zealand cattle tick, Haemaphysalis longicornis. No explanation could be found for the low prevalence of adult ticks on these hosts. The ears of both host species were almost the exclusive feeding site of the ticks and this may be a consequence of grooming behaviour. Another potential host, the rabbit, was examined but few were found to be infested.

The less restricted range of non-domesticated hosts, together with feeding habits that differ from domestic stock, make them an important additional source of information on the ecology and seasonal pattern of activity of H. longicornis. Also, they are a source of contamination for tick-free pasture, and could possibly maintain the tick population in the absence of sheep and cattle. It is important that their role as alternative hosts be understood and considered in tick-control programmes.  相似文献   

17.
Summary

The evidence for woodmanship in mediaeval Ireland is discussed. Palynological evidence dispels the continuing myth that there were vast mediaeval woods. Nonetheless, place name and documentary sources indicate discrete areas of woodland. At these places underwood was probably managed, livestock sheltered and fattened, berries and nuts gathered and timber felled. A range of historical texts and archaeological excavations support these claims. Woodland was an important aspect of the agricultural landscape and economy.  相似文献   

18.
Capsule?Accounting for changes in detectability over time which could invalidate population trends for common and widespread breeding birds in the UK, resulted in little change in trends for the majority of species considered.

Aims?To examine whether detectability has a significant influence on population trends for common and widespread breeding birds in the UK.

Methods?Using data collected over 16 years of the UK Breeding Bird Survey (1994–2009) and focusing on a random sample of 20 common and widespread bird species, we examine the extent to which controlling for temporal change in detectability would influence national population trends.

Results?Population trends were significantly different for only 2 of the 20 species, Common Blackbird and Winter Wren. This difference corresponds to an apparent fall off in detectability of these species between 2005 and 2009. For the remaining species, controlling for detectability resulted in no significant difference in population trends.

Conclusions?The importance of detectability should be examined as part of any long-term monitoring programme. However, currently we do not find sufficient support for routinely incorporating detectability into population trends for widespread and abundant breeding birds in the UK.  相似文献   

19.
Capsule: The data presented here demonstrate a considerable spatial overlap between wind farms and the breeding distribution of Hen Harriers in Ireland, but evidence for a negative impact of wind farms on their population is weak.

Aims: To assess the extent of the overlap between wind farms and breeding Hen Harriers and to investigate their potential impact on Hen Harrier population trends.

Methods: Data on Hen Harrier breeding distribution in 10?km?×?10?km survey squares from national surveys were used in conjunction with information on the location of wind farms to examine whether, and to what extent, changes in Hen Harrier distribution and abundance between 2000 and 2010 were related to wind energy development.

Results: Of the 69 survey squares holding Hen Harriers during the 2010 breeding season, 28% also overlapped with one or more wind farms. Data from 36 of the squares with breeding Hen Harriers during the 2000 survey revealed a marginally non-significant negative relationship between wind farm presence and change in the number of breeding pairs between 2000 and 2010.

Conclusions: A considerable overlap exists between Hen Harrier breeding distribution and the location of wind farms in Ireland, particularly in areas between 200 and 400?m above sea level. The presence of wind farms is negatively related to Hen Harrier population trends in squares surveyed in 2000 and 2010, but this relationship is not statistically significant, and may not be causal. This is the first study to assess the influence of wind energy development on Hen Harriers at such a large geographic and population scale.  相似文献   

20.
Abstract

Background and aims: Elevated low-density lipoprotein cholesterol (LDL-C) is causal risk for coronary artery disease (CAD) and LDL-associated variables including LDL-C, apolipoprotein B (apoB), non-high-density lipoprotein cholesterol (non-HDL-C), lipoprotein a [Lp(a)], small dense LDL (sd-LDL), and oxidized LDL (ox-LDL) have been widely used for predicting the risk of CAD. This study was aimed to compare the values of six LDL-related variables for predicting the severity of CAD using untreated patients undergoing coronary angiography (CAG).

Methods: A group of 1977 individuals were consecutively enrolled and divided into CAD (n?=?1151) and non-CAD groups (n?=?826) according to the results of CAG. LDL-C, apoB, non-HDL-C, Lp(a), sd-LDL and ox-LDL were measured, respectively. The numbers of stenotic arteries and Gensini Scores (GS) were used to calculate the severity of CAD and the associations of six variables with the severity of CAD and predicting value of these parameters were simultaneously examined.

Results: CAD patients had significantly higher concentrations of LDL-related variables than non-CAD ones (all p?<?0.05). Importantly, all variables rose with the increase in the severity of CAD. The predicting value of CAD manifested as sd-LDL?>?ox-LDL?>?apoB?>?non-HDL-C?>?LDL-C?>?Lp(a) [area under curve (AUC): sd-LDL 0.641; ox-LDL 0.640; apoB 0.611; non-HDL-C 0.587; LDL-C 0.583; Lp(a) 0.554; respectively]. In multivariate logistic analysis, all variables showed as independent risk factors for the severity of CAD [odds ratio (OR): ox-LDL?>?sd-LDL?>?apoB?>?non-HDL-C?>?LDL-C?>?Lp(a)].

Conclusions: All of LDL-related variables could be useful marker for predicting the severity of CAD but sd-LDL and ox-LDL appeared to litter better. Further study may be needed to validate our results.  相似文献   

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