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1.
Previous studies have shown negative associations between wind energy development and breeding birds, including species of conservation concern. However, the magnitude and causes of such associations remain uncertain, pending detailed ‘before‐after‐control‐intervention’ (BACI) studies. We conducted one of the most detailed such studies to date, assessing the impacts of terrestrial wind energy development on the European Golden Plover Pluvialis apricaria, a species with enhanced protection under European environmental law. Disturbance activity during construction had no significant effect on Golden Plover breeding abundance or distribution. In contrast, once turbines were erected, Golden Plover abundance was significantly reduced within the wind farm (?79%) relative to the baseline, with no comparable changes in buffer or control areas. Golden Plovers were significantly displaced by up to 400 m from turbines during operation. Hatching and fledging success were not affected by proximity to turbine locations either during construction or operation. The marked decline in abundance within the wind farm during operation but not construction, together with the lack of evidence for changes in breeding success or habitat, strongly suggests the displacement of breeding adults through behavioural avoidance of turbines, rather than a response to disturbance alone. It is of critical importance that wind farms are appropriately sited to prevent negative wildlife impacts. We demonstrate the importance of detailed BACI designs for quantifying the impacts on birds, and recommend wider application of such studies to improve the evidence base surrounding wind farm impacts on birds.  相似文献   

2.
Spearpoint, J. A., Every, B. & Underhill, L. G. 1988. Waders (Charadrii) and other shorebirds at Cape Recife, Algoa Bay, South Africa: seasonality, trends, conservation, and reliability of surveys. Ostrich 59: 166–177.

A total of 126 surveys of waders (Charadrii) and other shorebirds were made along 4 km of shore northwest of Cape Recife. The surveys were conducted bv two observers who counted independently of each other. The variability between observers was least for conspicuous species such as Whitefronted Plover, Blacksmith Plover, African Black Oystercatcher, Whimbrel and Grey Plover, but greatest for cryptic species such as Ringed Plover and for species which formed a minority in mixed flocks such as Curlew Sandpiper and Little Stint. Variability of surveys within years and between years is also considered. Turnstones and Sanderlings were the most abundant waders in summer. Of the Palaearctic waders, Turnstones, Grey Plovers, Sanderlings, Greenshanks and Whimbrels overwintered. In contrast, Ringed Plovers, Curlew Sandpipers, and Little Stints rarely overwintered. Little Egrets, Threebanded Plovers and Water Dikkops occurred mainly in winter. It is recommended that surveys to estimate numbers of Palaearctic waders in summer and winter should be conducted in December, January or February and June or July, respectively. Because of three-year cycles in breeding productivity of certain waders, surveys should be extended over at least three years. There was evidence that waders associated with rocky shores increased in numbers during the study period: this coincided with the erosion of sandy beaches near Cape Recife. Density, biomass and daily field metabolic rates, expressed on an area basis, were similar to those in eastern Scotland. Nine species of tern utilized Cape Recife. It is recommended that the bait-collecting regulations be enforced, that vehicles be prohibited on the beach, and that the tern roost and breeding site be fenced off to create a sanctuary.  相似文献   

3.
European Golden Plover Pluvialis apricaria populations have declined across Western Europe. Changes to upland grasslands that are utilized by foraging off-duty birds may have contributed to this decline. The use of enclosed agricultural land by a stable breeding population of Golden Plovers in the South Pennines is described to examine this hypothesis. Fields contained foraging plovers from the end of February to the end of July. Off-duty incubating birds commuted to feed on fields, females during the day and males at night. During the day, adults flew from 6.6 to 7.2 km from the nest to feed, whilst at night birds commuted from 2.4 to 2.7 km. The length of time spent foraging by males was inversely dependent upon daylength. Following hatching, the use of pasture declined, although not as much as in other studies. Arable and improved fields received most use by 15 radiotagged birds, whilst the use of pasture throughout the breeding season was negatively correlated with sward height. Adult diet consisted largely of subsurface prey, particularly larval tipulids, although earthworms were an important component in March and April. The biomass of larval tipulids was strongly correlated with an index of the use of fields. The selection of fields by Golden Plovers is therefore dependent upon prey abundance and availability, and, consequently, is likely to be enhanced by summer grazing and poor drainage. These findings are discussed in the light of recent trends in pastoral management.  相似文献   

4.
Human disturbance and its potential impacts upon bird populations are currently topical and contentious issues for conservationists. Although many studies have revealed a behavioural impact, or even direct effect on breeding success or survival, these cannot usually be extended to predict the impact on population size. Here we present a population model that allows predictions of the effect that changes in human numbers, visiting a 9-km-long section of the coastline, may have upon the size of a Ringed Plover Charadrius hiaticula population. Human disturbance affects Ringed Plovers in our study area through birds avoiding areas of high disturbance and, in addition, through the accidental trampling of a small number of nests by people walking on the beach. Using the level of human disturbance and habitat variables (which define territory quality) it is possible to predict which areas of beach are occupied and therefore the sites available to the population. Breeding success, for a given area of beach, can be predicted from habitat data. Incorporating known, density-independent, adult mortality allows the equilibrium population size to be predicted. This provides a model that predicts population size. This model is then used to predict the population that the site would support with different, hypothetical, levels of disturbance. If nest loss from human activity was prevented, for example by fencing nests, we predict the Plover population size would increase by 8%. A complete absence of human disturbance would cause a population increase of 85%. If the numbers of people were to double, we predict the population would decrease by 23%.  相似文献   

5.
Fennoscandian alpine tundra habitats support large numbers of breeding waders, but relatively little is known about their breeding ecology despite the fact that this habitat is threatened by climate change. We studied habitat selection, diet and prey availability of European (Eurasian) Golden Plover Pluvialis apricaria chicks at the Vindelfjällen Nature Reserve, Ammarnäs, Sweden. Information from 22 chicks tracked using radio‐transmitters was analysed. By analysing 149 faecal samples, four main prey taxa were identified, Coleoptera (40%), Bibionidae (31%), Hymenoptera (13%) and Tipulidae (10%). We found that chicks switched from feeding on Tipulidae to feeding on Bibionidae as they grew, and that this switch coincided with a shift from the use of the habitat where Tipulidae were abundant (alpine meadow/heathland) to the use of the habitat were Bibionidae were abundant (Willow shrub). Although chicks track food availability to some extent, the link between prey availability and habitat use was not perfect, indicating that additional factors other than food abundance, such as shelter from predators, determine habitat selection. Bibionidae are an important prey for Golden Plover chicks as it is the only prey group that has a late summer flush in abundance, in contrast to the general decline of total arthropod biomass during the chick‐rearing period. However, Bibionidae imagoes only occurred in 2011 and were virtually absent in 2013, which relates to the species’ ecology with 2‐ to 5‐year cycles in mass occurrence. Extreme annual variation in an essential food source such as Bibionidae imagoes might have an important effect on the condition and survival of Golden Plover chicks, an important subject for future studies. The foraging conditions for Golden Plover chicks in Fennoscandia appear to be different to those in the UK, where the chicks rely mainly on a Tipulidae flush only.  相似文献   

6.
The Crab Plover Dromas ardeola is the only waterbird species known to provision offspring well after the post-reproductive migration and through overwintering. A few previous quantitative studies have reported inconclusively that juveniles begged rarely, and also indiscriminately at other juveniles. Here, we describe the feeding behaviour of adult and juvenile Crab Plovers during the first part of the wintering period. Juveniles begged frequently for food, always toward adults, and obtained 0.1 prey items/min from them. Begging birds obtained the largest prey items of those captured by the adults. When foraging alone, juveniles captured prey at the same rate as adults, but captured smaller crabs. The feeding success of adults was not altered by the presence of the begging juvenile. Juveniles depended partly on adults during the first part of the overwintering period, but were almost independent towards the end. Crab Plovers may adopt such unusually prolonged care because they need to abandon their breeding areas quickly, when environmental conditions are extreme. Large numbers of Crab Plovers overwinter in a few areas, now subject to human alteration. Isolated adults may forage on other areas such as narrow and disturbed shores, but juveniles may require wide beaches, suitable for group foraging, that should be considered as key areas for the recruitment of juveniles into the population.  相似文献   

7.
Golden plovers and Grey Plovers Pluvialis spp. all have very distinct breeding plumage rich in contrast, with a conspicuous black belly and breast bordered by a bright white fringe. Eurasian Golden Plovers are known partly to replace their breeding plumage with striped yellow feathers during incubation, different from both breeding and non-breeding plumages. In this study a similar partial breeding moult was observed in Pacific Golden Plovers and American Golden Plovers caught on the nest or collected during incubation, although the feathers did not differ clearly from those of non-breeders. This moult starts during incubation and precedes the post-breeding moult into non-breeding plumage. Because the lighter feathers reduce the contrast between the black belly and the white flanks, we suggest that during incubation the plumage characteristic that plays an important role in mate choice is no longer important; at this stage it is better for the bird to be inconspicuous. Additional information on museum skins of golden plovers and of Grey Plovers indicated that only the three golden plovers undergo this partial moult, but that Grey Plovers in general retain full breeding plumage throughout incubation. The three golden plovers also resemble each other in their generally very passive nest defence strategies. In contrast, the larger Grey Plovers actively chase and attack aerial and ground predators. Thus, a reduced conspicuousness of the body plumage during incubation is likely to benefit the golden plovers more than the Grey Plover. We suggest that nest defence behaviour, plumage characteristics and perhaps size have co-evolved as a response to different selection pressures in golden plovers and Grey Plover, but alternative hypotheses are also discussed.  相似文献   

8.
The growth of Golden Plover Pluvialis apricaria chicks is modelled in detail for the first time. The pattern of growth is typical of postnatal development in waders, although the mean fledging time of 37 days is slower than would be expected from adult body weight. Bill length and weight at hatching had significant effects on the rate of weight gain shown by 2-day-old chicks, although this effect was not noticeable at 4 days of age. Chick survival was significantly affected by bill length, as a result of the variation in weight gain. The growth of older chicks was positively correlated with mean minimum temperature. The slow rate of growth exhibited by Golden Plover chicks is discussed in relation to breeding habitat and the effects of weather and hatchling biometrics.  相似文献   

9.
The breeding habitat preferences of Kentish Plover and Little Ringed Plover were studied on a shingle bed. The location of each nest was measured as the distance to the sea wall, nearest pond and nearest path. The habitat surrounding nests was measured at radii of 0.15 m and 15 m as the proportional cover of shingle, gravel, sand, live and dead vegetation. When all variables were considered simultaneously, the differences between the habitats used by the species were related to the cover of shingle within 15 m of the nest and the distance to the sea wall. Nest sites located close to the sea wall and with high shingle cover almost always belonged to Kentish Plover, while those more distant and with low shingle cover almost always belonged to Little Ringed Plover. Kentish Plover nested in areas of newly exposed shingle, while Little Ringed Plovers used areas which had been stable for longer and hence were colonized by vegetation. This study suggests that management which maintains a high proportion of exposed substrate on shingle beds will increase their suitability for Kentish Plover.  相似文献   

10.
Capsule: The 2007 national survey of the UK breeding population of Little Ringed Plovers shows a further spread into Scotland and Wales since the previous survey in 1984. In contrast, there has been a significant decrease in the Ringed Plover breeding population.

Aims: To provide new breeding population estimates in the UK and Great Britain for Little Ringed Plover Charadrius dubius and Ringed Plover Charadrius hiaticula in 2007 and investigate changes in breeding distribution and habitat use since 1984.

Methods: Breeding population estimates were made by combining counts of pairs from ‘key sites’ (2?×?2?km tetrads known to be occupied in/since 1984) and estimates of the numbers of pairs away from these sites based on stratified sampling. Survey periods for Little Ringed Plover: 15 April to 15 July, three visits; Ringed Plover: 15 April to 30 June, two visits.

Results: Population estimates, for 2007, of 1239 (95% confidence intervals: 1175–1311) pairs of Little Ringed Plover and 5291 (5106–5478) pairs of Ringed Plovers were calculated for Great Britain, with 5438 (5257–5622) pairs of Ringed Plover estimated in the UK. Counts of Ringed Plover at inland and coastal sites, covered in both 1984 and 2007, decreased by 83% and 53%, respectively. The Little Ringed Plover population has expanded in range northward and westward since 1984. Main habitats used in 2007 by Little Ringed Plover were inland gravel and sand (25.9%) and river shingle (17.8%); and, for Ringed Plover, coastal shingle and sand (38.5% and 13.7%, respectively) and machair plus associated habitats (23.8%) in the Outer Hebrides.

Conclusions: Between 1984 and 2007, the Little Ringed Plover breeding population in the UK increased considerably, expanding northward and westward, with increased use of river shingle habitats. During the same period Ringed Plover breeding numbers in the UK declined considerably in both coast and inland habitats, likely to be due to human disturbance and habitat change, respectively.  相似文献   

11.
12.
Disturbance of wildlife is a potential cause of conservation concern, not least to overwintering waders Charadrii inhabiting estuaries close to conurbations where human recreational and economic activities are often concentrated. Disturbance from people on and alongside intertidal foraging areas could make it more difficult for birds to survive until spring in good condition by reducing the time available for foraging, increasing energy requirements and displacing birds to poorer foraging areas. We adopted a two-part approach to testing whether such significant impacts occurred in a Special Protection Area where disturbance risk was high because of its small size and close proximity to conurbations. In part one, we recorded over the whole estuary during stages of the tidal cycle when part or all of the intertidal zone was exposed and so accessible to waders (i.e. on receding, low and advancing tides): (1) the numbers and activities of people on the intertidal flats and on the adjacent land in those places where people were visible to waders in the intertidal zone and (2) the numbers of waders present and disturbed into flight, the flight distance and flight duration in the ‘overlap’ areas where people did disturb waders. People occurred on < 25% of the 938 ha of intertidal flats, but most waders foraged on mudflats, whereas most people were on sandflats. People on land were visible to foraging waders along < 35% of the 16.5 km of shoreline. Waders and people were therefore substantially separated in space. Within overlap areas, people and waders were often frequently separated in time: for example, people on land mostly disturbed waders when only the upper shore levels were exposed. The average overwintering wader spent < 0.1% of its foraging time during daylight flying away from people and the additional energy expenditure was equivalent to < 0.02% of its daily requirements. The comparison made in part two between our study area and two comparable estuaries showed that the number of visits each day to the overlap areas would need to be 29 or 43 times greater for disturbance to have lowered the birds’ body condition and winter survival. Both parts of the study therefore suggested strongly that the amount of disturbance was too trivial to have a significant impact on waders. It is concluded that: (1) to properly assess disturbance risk to waders, both extensive and intensive observations must be made on the behaviour of people and birds to quantify the extent to which they overlap in space and time, and (2) it should not be assumed that an estuary's close proximity to conurbations, and the presence of large numbers of people in the vicinity of the SPA, necessarily implies a significant disturbance risk to waders.  相似文献   

13.
The results of annual censuses of a Golden Plover population in the Peak District, covering 24 years, are analysed. A strong density-dependent effect of the population in the previous year explained 26.7% of the variation in population growth. An additional 15.3% of the variation was accounted for by the severity of winter weather, as measured by mean monthly air temperature for November to February. There was no significant effect of weather during the breeding season upon Golden Plover population size, implying that any effects which spring and summer temperature or rainfall may have upon fledging success are masked by other factors. The importance of these results is discussed in the light of work on other wader species, and possible declines in Golden Plover numbers.  相似文献   

14.
Raptor predation on wintering waders in southeast Scotland   总被引:4,自引:2,他引:2  
D. PHILIP WHITFIELD 《Ibis》1985,127(4):544-558
Predation on waders was investigated over the winters of 1982-83 and 1983-84 at a rocky shore and a small estuary in southeast Scotland. Probably all the waders which were found after being eaten were killed by raptors; mammalian predation and death due to severe weather were of minimal importance in comparison to the effects of raptor predation. Sparrowhawks were probably the major predators of waders at both sites, but owls also took some. Differences were found between the rocky shore and the estuary in the species of raptors which were seen (more Peregrines and Merlins seen on the estuary) and in the numbers of wader kills which had been plucked and eaten on open ground (more open ground pluckings, indicative of Peregrines and Merlins, found on the estuary). It is suggested that Peregrines and Merlins took more waders at the estuary due to their preference for hunting over large open expanses. Winter mortality rates due to predation varied in different species of waders: at the rocky shore the Redshank suffered the heaviest winter mortality (20% and 16%) whilst on the estuary the Ringed Plover had the highest winter mortality (19%). At both sites no large waders such as Curlews and Oystercatchers died as a result of predators and for these species other factors, such as severe weather or starvation, appeared to be a greater source of mortality. Significantly more juvenile Redshanks, Turnstones and, probably, Dunlin and Ringed Plovers were found eaten than was expected from the age-composition of their respective populations. In the Redshank and Turnstone several differences in the behaviour of juveniles and adults were discovered which may have made juveniles more vulnerable to predation.  相似文献   

15.
There is evidence that zoo visitor presence can influence the behaviour and, in some cases, adrenal response of zoo animals, and can sometimes compromise animal welfare. In some laboratory studies, significantly more primate births have been reported on weekends, when fewer people are working there, compared with weekdays when staffing levels are at their highest. Here, we investigate whether there is evidence of a “weekend effect” on births in zoo animals as a result of visitor numbers. Unlike laboratories, zoos are typically busier with visitors on weekends than on weekdays, although staffing levels remain fairly consistent across days of the week. If zoo animal parturition is sensitive to human presence, then fewer births would be expected on weekends compared with weekdays. We tested this using birth data and visitor numbers on the entrance gate from zoo records across 16 species representing artiodactyls, perissodactyls, carnivores and primates at four British zoos, to see whether there is an association between mean daily birth rates and average visitor numbers. We predict that, if there is a visitor effect, daily births should be lower on weekends than weekdays and should correlate with mean daily visitor numbers. Results showed that births for all 16 species were randomly distributed through the week, and there was no significant decline in births on weekends. We conclude that the “weekend effect”, if such a thing exists, does not appear to be a feature of zoo births, suggesting that elevated weekend visitor numbers are not sufficiently stressful to trigger delayed parturition.  相似文献   

16.
The issue of predator limitation of vertebrate prey populations is contentious, particularly when it involves species of economic or conservation value. In this paper, we examine the case of raptor predation on upland passerines and waders in Scotland. We analysed the abundance of five wader and passerine species on an upland sporting estate in southern Scotland during an eight-year period when hen harrier, peregrine and merlin numbers increased due to strict law enforcement. The abundance of meadow pipit and skylark declined significantly during this time. Golden plover also showed a declining trend, whereas curlew increased significantly and there was a near significant increase in lapwings. Contrasting the local population trends of these species with trends on nearby areas revealed higher rates of decline for meadow pipit and skylark at the site where raptors increased, but no differences in trends for any of the three wader species. There was a negative relationship between the number of breeding harriers and meadow pipit abundance the same year and between total annual raptor numbers and meadow pipit abundance. Predation rates of meadow pipit and skylark determined from observations at harrier nests suggested that predation in June was sufficient to remove up to 40% of the June meadow pipit population and up to 34% of the June skylark population. This 'quasi-natural' experiment suggests that harrier predation limited the abundance of their main prey, meadow pipit, and possibly the abundance of skylark. Thus, high densities of harriers may in theory reduce the abundance of the prey species which determine their breeding densities, potentially leading to lower harrier breeding densities in subsequent years. We found no evidence to suggest that raptor predation limited the populations of any of the three wader species. We infer that concerns over the impact of natural densities of hen harriers on vulnerable upland waders are unjustified.  相似文献   

17.
于2006年至2009年间对环青海湖鸻鹬类的群落特征和时空分布进行了资源调查,以期对青海湖保护管理提供科学依据。根据青海湖的地形、植被和水系分布以及水鸟聚集特点,环青海湖选择了15个调查地点,采用直接计数法进行了14次调查,并应用Shannon-wiener指数进行了多样性分析。共记录到鸻鹬类4科28种。数量上红脚鹬(Tringa totanus)、环颈鸻(Charadrius alexandrinus)和黑尾塍鹬(Limosa limosa)是当地的主要物种,分别占鸻鹬类调查总数的33.3%、22.0%和16.2%。分布上环颈鸻最为广泛,在各调查地点均有发现,其次为红脚鹬、黑尾塍鹬和青脚滨鹬(Calidris temminckii),分布地点达10处以上。黑马河和布哈河口多样性较高,这与其适宜的河漫滩和沼泽等栖息环境以及丰富的食物有关。季节上8~10月多样性较高,其次是4~5月。青海湖鸻鹬类的数量高峰依次为10月、8月和5月,物种数高峰为8月和4月,并且秋季物种数高于春季。主要物种红脚鹬和环颈鸻的迁徙动态较为一致,均是8月份达到全年数量最高值,次高峰为5月和10月;黑尾塍鹬的数量在10月份达到全年最高峰。青海湖鸻鹬类迁徙时间与渤海湾较为一致,这可能与历史上长期形成的迁徙模式有关。鄱阳湖和洞庭湖的鸻鹬类主要物种与青海湖比较接近,但数量远远多于青海湖。近年来,游客和游船等人为活动的增加导致青海湖产生局部污染,因此应重视环青海湖生态环境的保护管理,减少对鸻鹬类等水鸟栖息地的人为干扰。  相似文献   

18.
When censusing breeding waders in large upland areas, the time of day has a major influence on the numbers of birds detected.  相似文献   

19.
ABSTRACT.   Snowy Plovers ( Charadrius alexandrinus ) and Wilson's Plovers ( C. wilsonia ) are shorebird species of increasing conservation concern, with populations apparently declining in North America. However, estimates of current populations are needed before initiating long-term monitoring or planning. In 2004, we estimated abundance of breeding Snowy and Wilson's plovers in the lower Laguna Madre region of Texas using occupancy abundance estimation. We made repeated visits to survey plots from April to June, recording the number of adults of both species observed and the amount of suitable breeding habitat within each plot. We considered Bayesian occupancy abundance models with and without habitat covariates to explain the abundance of both species. For both Snowy and Wilson's plovers, the number of birds counted in each plot was influenced by the amount of suitable breeding habitat within the plot (Snowy Plover αhabitat= 0.52, SD = 0.10, 95% CI = 0.33–0.71; Wilson's Plover αhabitat= 0.48, SD = 0.12, 95% CI = 0.24–0.71). Using the habitat covariate models for each species, we estimated that 416 adult Snowy Plovers (95% CI = 394–438) and 279 adult Wilson's Plovers (95% CI = 262–296) were present in our study area. Our results illustrate the use of a relatively new method for abundance estimation, and indicate that the lower Laguna Madre region of Texas is an important breeding area for both Snowy and Wilson's plovers. Given the documented and suspected population declines for Snowy and Wilson's plovers, we recommend protection of their breeding habitats along the coast of Texas from development and degradation resulting from unregulated use.  相似文献   

20.
This paper presents data from a twelve-year (1986–98) monitoring of waterbird populations at Muni Lagoon, and discusses the ornithological importance of the lagoon and trends in the use of the site by waterbirds. The small brackish lagoon forms part of the Muni-Pomadze Ramsar site situated on the Ghana coast. A total of 48 species of waterbirds were recorded at the site comprising of 29 species of waders, eight species of terns, two species of gulls, seven species of herons and egrets, one species each of duck and cormorant. The most abundant waterbirds species recorded on the site were the Curlew Sandpiper, Ringed Plover, Greenshank, Black-winged Stilt, Common Tern, Black Tern, Royal Tern and the Sandwich Tern. Three species of waders, Black-winged Stilt, Pratincole and Little Tern were observed to breed at the site. The highest numbers of waterbirds occurred on the site in the period September to March. The site remains an internationally important wetland site by virtue of supporting internationally important numbers of four species of terns: Royal Tern, Sandwich Tern, Common Tern and Black Tern. The value of Muni lies more in its use as a feeding/staging site for migrating waders that spend the non-breeding season in Ghana or pass through to winter further south, and as a roosting site for terns which feed mainly at sea. The use of the site by waterbirds has increased by some 400% between 1986 and 1998. This is attributed to improved prey availability resulting from the opening of the lagoon into the sea during the 1994 floods, and reduced disturbance of feeding and roosting birds. This would imply that the value of the site as waterbird habitat could improve considerably with appropriate habitat management interventions and continued protection.  相似文献   

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