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1.
Birds use change in daylength during the year to time events during their annual cycles. Individual Eurasian siskins Carduelis spinus can breed and winter in widely separated areas in different years. Birds at different latitudes will experience different changes in photoperiod. So how does latitude affect photoperiodic control? Our aim in this study was to find whether Siskins caught from the wild in Britain and exposed to different photoperiodic regimes, typical of widely separated latitudes, would differ in the subsequent timing and duration of their moults and associated processes. Siskins were caught in late February and early March, and initially kept outside on natural photoperiods. From the spring equinox (21 March), they were divided into three groups kept under photoperiodic regimes that simulated latitudes 40°, 55° and 70°N respectively. All three groups showed highly significant subsequent changes in body mass, fat scores and cloacal protuberance size. Moult of the primary feathers started during June – August (mean 9 July), and lasted 61–99 days (mean 75 days). Birds that started to moult late in the season had shorter moult durations. All individuals showed lower mass and fat levels during moult than before or after moult. Crucially, there were no significant differences in the timing of these events between the three photoperiodic groups. Apparently these birds did not use prevailing absolute photoperiod or the prevailing rate of change in photoperiod to time moult‐related seasonal events, but used instead some other feature of the annual photoperiod cycle or some form of interval timer linked to photoperiod.  相似文献   

2.
We studied the nonbreeding ecology of Bristle-thighed Curlews Numenius tahitiensis from 1988 to 1991 on Laysan Island in the Northwestern Hawaiian Islands. Using capture-recapture analysis, we estimated that 300–350 curlews wintered on the island. Annual survival was >85% for adults and 92% for first-year birds. Young birds remained on the island until at least their third calendar year, when some individuals made "exploratory" visits to other islands in the Northwestern chain. Most of the birds marked in their first year migrated north to the breeding grounds when they were 3 years old; several birds remained on the island until they were at least 4 years old. Adults returned to the same discrete home ranges year after year, whereas subadults (which do not migrate) tended to use a greater portion of the island. At least 60% of the subadults marked from 1988 to 1990 returned to the island to winter as adults. Because young curlews arrived after adults and experienced high survivorship while on the island, there did not appear to be intense competition for space at Laysan even though the island is at the northern end of the species' winter range.  相似文献   

3.
2009年4月至2010年1月,对西藏南部羊卓雍错的水鸟资源状况进行了调查。采用定点观察的方法,沿湖选择了24个观察点,分别在繁殖前期、中期和后期,以及秋季和冬季进行了6次调查。采用核密度分析(Kernel analysis)的方法,对两只卫星跟踪斑头雁(Anser indicus)的活动区进行了分析。调查期间,记录到水鸟32种31044只,隶属于6目10科。雁鸭类和鸥类分别占水鸟总数73.9%和19.1%,主要是斑头雁、赤嘴潜鸭(Rhodonessa rufina)、赤麻鸭(Tadorna ferruginea)、棕头鸥(Larus brunnicephalus)等。水鸟多样性较高的季节是春秋迁徙季节。羊卓雍错夏季主要的繁殖种群是斑头雁和棕头鸥,也有少量黑颈鹤(Grus nigricollis)的繁殖个体;冬季主要物种是赤嘴潜鸭,经常聚集在融化的冰面上。春季斑头雁的数量增加趋势较为明显;进入繁殖期后,斑头雁处于孵卵阶段,繁殖种群的数量达到2000余只;繁殖后期,斑头雁换羽结束,成鸟带领幼鸟在鸟岛附近的湖边取食,此时观察到斑头雁的数量又有明显的增加;秋季斑头雁的南迁致使种群数量呈下降趋势;冬季许多斑头雁从北方如青海湖等地迁来越冬使得种群数量有所增加,多分布于湖西浪卡子县城附近的沼泽湿地和湖南部的绒波臧布河流的入口处。卫星跟踪结果表明,羊卓雍错是青海湖繁殖的斑头雁重要的越冬地之一,湖西部沼泽湿地和湖南部的河流入口处是其主要活动区域,而且该湖与雅鲁藏布江河谷之间通过斑头雁的往来移动存在着联系,因而是西藏南部禽流感监测的重要地点。  相似文献   

4.
For many migratory bird species, the latitudinal range of the winter distribution spans thousands of kilometres, thus encompassing considerable variation in individual migration distances. Pressure to winter near breeding areas is thought to be a strong driver of the evolution of migration patterns, as individuals undertaking a shorter migration are generally considered to benefit from earlier arrival on the breeding grounds. However, the influence of migration distance on timing of arrival is difficult to quantify because of the large scales over which individuals must be tracked. Using a unique dataset of individually‐marked Icelandic black‐tailed godwits Limosa limosa islandica tracked throughout the migratory range by a network of hundreds of volunteer observers, we quantify the consequences of migrating different distances for the use of stop‐over sites and timing of arrival in Iceland. Modelling of potential flight distances and tracking of individuals from across the winter range shows that individuals wintering further from the breeding grounds must undertake a stop‐over during spring migration. However, despite travelling twice the distance and undertaking a stop‐over, individuals wintering furthest from the breeding grounds are able to overtake their conspecifics on spring migration and arrive earlier in Iceland. Wintering further from the breeding grounds can therefore be advantageous in migratory species, even when this requires the use of stop‐over sites which lengthen the migratory journey. As early arrival on breeding sites confers advantages for breeding success, the capacity of longer distance migrants to overtake conspecifics is likely to influence the fitness consequences of individual migration strategies. Variation in the quality of wintering and stopover sites throughout the range can therefore outweigh the benefits of wintering close to the breeding grounds, and may be a primary driver of the evolution of specific migration routes and patterns.  相似文献   

5.
The habitats and foods used by a sample of marked individuals and by the whole population of Oystercatchers Haematopus ostralegus wintering on the Exe estuary, South Devon, are described. In the spring and early summer, only a few hundred immatures were present. Two thousand adults and several hundred juveniles arrived in late summer from the breeding grounds and remained until the following spring. The majority of the birds were then adults. At low water, most adults fed on the mussel Mytilus edulis beds and ate mussels. Most individuals specialised on this prey and ate little else. Some adults fed on mud-flats and sandflats within the estuary and along the coast, and specialised on a mixture of Nereis diversicolor and Scrobicularia plana or on Cerastoderma edule or Littorina spp. Though some juveniles ate mussels from the time they arrived, most did not. In winter, they took Scrobicularia on mudflats, earthworms Lumbricidae and leatherjackets Tipulidae larvae in fields and Spisula and mussels along the coast. At other times of year they mainly ate Nereis. However, as they grew older, more birds began to specialise on mussels, especially in their second, third and fourth summers when the adults were away. At high water, most birds roosted at the mouth of the estuary or along the coast. However, several hundred fed in the fields in winter with more doing so late in the winter on warm days on Neap tides when less time was available for feeding on the estuary in daylight. Birds feeding on Nereis and Scrobicularia at low water were most often seen in the fields, irrespective of age. Birds feeding on Mytilus and Littorina occurred there rarely, but no bird eating Cerastoderma was seen there. The findings are discussed in relation to age differences in feeding skills and ability to compete successfully with other birds.  相似文献   

6.
Whereas matrix management has recently been suggested as a useful tool in biodiversity conservation, patterns and processes within matrices remain unknown. We examined the effects of the loss and fragmentation (configuration) of original deciduous habitats on birds in larch plantation matrix in the winter and during the breeding season in a montane region in Nagano Prefecture, central Japan. Birds were counted using a plot-count method from 32 (winter) and 46 (breeding) matrix (plantation) sites with a range of surrounding habitat loss and fragmentation at a 1600-m scale. Birds were assigned to species groups based on ecological traits, and three groups for which larch plantation would function as low-quality matrix were analyzed. Bird occurrences were explained primarily by habitat structure. Although the effects of landscape structure were less than those of habitat structure, three of five groups across the two seasons experienced significant landscape effects. All effects were of habitat fragmentation (scatteredness of deciduous habitats), i.e. two groups (flycatchers in the breeding season and tree nesters in both seasons) frequently occurred in matrix surrounded by highly scattered deciduous habitats. However, most of these effects were confounded by local habitat structure. That is, the variation in bird occurrences explained purely by fragmentation variables was <6%. Nonetheless, because these effects were marginally significant at p<0.10, there was some support for fragmentation effects after covariation with habitat structure was considered. Based on these results and associated theoretical studies, we hypothesized that habitat fragmentation leads to loss of individuals and is more important than habitat loss in landscapes with a structurally similar matrix. We also hypothesized that matrix within landscapes with highly scattered habitats should be managed with high priority.  相似文献   

7.
Dunlin Calidris alpina is one of the most abundant shorebirds using coastal habitats in the East Atlantic migratory flyway, that links arctic breeding locations (Greenland to Siberia) with wintering grounds (West Europe to West Africa). Differential migration and winter segregation between populations have been indicated by morphometrics and ringing recoveries. Here, we analyse the potential of genetic markers (mitochondrial DNA – mtDNA) to validate and enhance such findings. We compared mtDNA haplotypes frequencies at different wintering sites (from north-west Europe to West Africa). All birds from West Africa had western (European) haplotypes, while the eastern (Siberian) haplotypes were only present in European winter samples, reaching higher frequencies further north in Europe. Compilation of published results from migrating birds also confirmed these differences, with the sole presence of European haplotypes in Iberia and West Africa and increasingly higher frequencies of Siberian haplotypes from south-west to north-west Europe. Comparison with published haplotype frequencies of breeding populations shows that birds from Greenland, Iceland, and North Europe were predominant in wintering grounds in West Africa, while populations wintering in West Europe originated from more eastern breeding grounds (e.g. North Russia). These results show that genetic markers can be used to enhance the integrative monitoring of wintering and breeding populations, by providing biogeographical evidence that validate the winter segregation of breeding populations.  相似文献   

8.
The Mediterranean Sea is known as an ecological barrier for numerous migratory birds flying from European breeding grounds to African wintering sites. Birds generally avoid migration over open sea and fly over land. In the Mediterranean Basin, few land bridges or bottlenecks for migratory birds exist. The narrowest are at the western and eastern extremes: the Strait of Gibraltar and Israel. Comparative studies between these locations are extremely rare to date. Therefore, in order to elucidate the differences between the two flyways, we compared data collected simultaneously for two sister leaf warbler species, the Bonelli’s Warbler complex, Phylloscopus bonelli and Phylloscopus orientalis, at ringing stations in the western Mediterranean Basin Gibraltar, and the eastern Eilat, Israel. Data on biometrics and passage dates of individuals trapped at Gibraltar and Eilat were used, and it was found that mean arrival date of Western Bonelli’s Warblers at Gibraltar was 15 days later than Eastern Bonelli’s Warblers at Eilat. Furthermore, Western Bonelli’s Warblers had shorter wings than Eastern Bonelli’s Warblers. On the other hand, birds in Eilat were in poorer body condition than individuals in Gibraltar. The comparison between geographically distant stop-over sites contributes to furthering our understanding of the development of migration strategies across ecological barriers in sibling species. Our study showed that populations that breed in southwestern Europe migrate through Gibraltar and winter in West Africa are able to accomplish migration in comparatively good body condition. This is in contrast to those that winter in East Africa, migrate through Israel and have to endure the combined challenge of crossing the Sahel, Sahara and Sinai deserts before reaching their breeding grounds across southeast Europe and southwest Asia. Hence, the discrepancies described between the western and the eastern flyway suggest that individuals in the west, in general, migrate shorter distances, have a physiologically less demanding crossing of the North African deserts and appear to stage before their crossing the Strait of Gibraltar, a privilege unavailable to the migrants of the eastern flyway.  相似文献   

9.
Recent warming has caused a northern extension in the distribution of many southern fish species in Icelandic waters. Polar cod (Boreogadus saida) around Iceland are near the southern limit of their distribution, but are poorly studied in the area. Therefore, material sampled during demersal fish surveys in March 1985–2013 and in pelagic 0-group surveys in Iceland–East Greenland waters in August–September 1974–2003 was used to investigate their distribution, abundance and biology. Demersal polar cod were most often caught on the outer shelf to the north-west and north of Iceland, but during years of widest distribution and highest abundance, they were caught farther to the east on the northern shelf. Pelagic 0-group polar cod were only caught sporadically and mainly confined to the waters off the north-west shelf of Iceland and the East Greenland shelf (southern Denmark Strait). In demersal hauls, the number of stations with polar cod decreased with increasing bottom temperature and polar cod were most widely distributed in the years 1989, 1994 and 1995. Highest numbers of demersal polar cod per haul were caught at temperatures of ?0.5 to 2.5 °C and at 200–450 m depth. The length of demersal polar cod ranged from 5 to 32 cm, while the fish caught in the pelagic trawl ranged from 2.2 to 19 cm. The polar cod in the subarctic waters north of Iceland most likely originate from the waters off East Greenland and further warming and decline in sea ice may eventually lead to the disappearance of polar cod from Icelandic waters.  相似文献   

10.
From 1999 to 2005 at Zvenigorod Biological Station (Moscow oblast, Russia, 55°44′N, 36°51′E) field studies were performed. Birds were trapped using mist-nets. The Russian Ringing Center provided data collected from 1948 on robins captured outside the Moscow oblast. A total of 5751 robins were trapped and banded in the Moscow oblast. Only two birds (0.03%) were retrapped the following years. Three birds banded in the Moscow oblast were found in other regions. In addition, two robins banded in other countries were caught at Zvenigorod Biological Station. The rate of long-distance recoveries was 0.09%. The Russian Ringing Center reports on three robins banded in other countries and found in the Moscow oblast, and one robin banded in the Moscow oblast and then found in a different country. It was shown that robins born or breed in the Moscow oblast exhibited neither nest-site fidelity nor natal homing, which is the case for other areas. Wintering grounds of robins born or breed in the Moscow oblast are located within a single zone (north-east of Spain, south of France and Italy). This area is also wintering ground for robins from other regions. There exists one route connecting the wintering grounds for robins with the Moscow oblast which birds follow during autumn and spring migrations. It is possible that the Moscow oblast is a nesting area for robins born or breed in the north of Russia (including Finland and the Leningrad oblast). Natal sites and nest sites of robins could be separated by a distance of 1000 km or more.  相似文献   

11.
The objectives of this study were to describe and evaluate potential drivers of genetic structure in Canadian breeding populations of the Ovenbird, Seiurus aurocapilla. We performed genetic analyses on feather samples of individuals from six study sites using nuclear microsatellites. We also assessed species identity and population genetic structure of quill mites (Acariformes, Syringophilidae). For male Ovenbirds breeding in three study sites, we collected light‐level geolocator data to document migratory paths and identify the wintering grounds. We also generated paleohindcast projections from bioclimatic models of Ovenbird distribution to identify potential refugia during the last glacial maximum (LGM, 21,000 years before present) as a factor explaining population genetic structure. Birds breeding in the Cypress Hills (Alberta/Saskatchewan) may be considered a distinct genetic unit, but there was no evidence for genetic differentiation among any other populations. We found relatively strong migratory connectivity in both western and eastern populations, but some evidence of mixing among populations on the wintering grounds. There was also little genetic variation among syringophilid mites from the different Ovenbird populations. These results are consistent with paleohindcast distribution predictions derived from two different global climate models indicating a continuous single LGM refugium, with the possibility of two refugia. Our results suggest that Ovenbird populations breeding in boreal and hemiboreal regions are panmictic, whereas the population breeding in Cypress Hills should be considered a distinct management unit.  相似文献   

12.
Previous studies have shown considerable variability in morphological features and the existence of genetically distinct sibling species in the acanthocephalan Echinorhynchus gadi Zoega in Müller, 1776. The aim of the present study was to follow up and extend those earlier studies by using a combination of DNA analysis and morphometrics to investigate differences between samples of E. gadi from Atlantic cod Gadus morhua L. caught at five fishing grounds in the Baltic Sea and three in different parts of the North Atlantic. Twelve morphological features were measured in 431 specimens of E. gadi, 99 individuals were studied by polymerase chain reaction-restriction fragment length polymorphosm (PCR-RFLP), and selected PCR products were sequenced. The molecular analyses showed the nucleotide sequences of E. gadi rDNA from cod caught at all the sampling sites to be identical. The comparative morphological study, in contrast, revealed significant differences between samples of E. gadi from different sampling sites and showed the separation of E. gadi into two groups corresponding approximately to the systematic classification of cod into the two subspecies, Atlantic G. morhua morhua and Baltic G. morhua callarias. The E. gadi infrapopulation size had a significant effect on some of the morphological features. The results are discussed in relation to cod population biology, the hydrography of the study area and the history of the Baltic Sea formation.  相似文献   

13.
In this paper we apply molecular methods to study the colonization of islands off the west coast of Scotland by the common shrew ( Sorex araneus L.), and current gene flow. We collected 497 individuals from 13 islands of the Inner Hebrides and Clyde Island groups and six mainland regions. Individuals were genotyped at eight microsatellite loci, and the mitochondrial cytochrome b sequence (1140 base pairs) was obtained for five individuals from each island/mainland region. Based on these molecular data, island colonization apparently proceeded directly from the mainland, except for Islay, for which Jura was the most likely source population. Raasay may also have been colonized by island hopping. Most island populations are genetically very distinct from the mainland populations, suggesting long periods of isolation. Two exceptions to this are the islands of Skye and Seil, which are geographically and genetically close to the mainland, suggesting in each case that there has been long-term gene flow between these islands and the mainland. We consider possible methods of island colonization, including human-mediated movement, swimming, and land and ice bridges.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 797–808.  相似文献   

14.
The present study reports the discovery of the hitherto unknown breeding grounds of the large‐billed reed warbler Acrocephalus orinus in the Badakhshan region of Tajikistan. A total of eight adult individuals were caught at three riverine woodland sites and breeding was confirmed at one locality. The identity of the birds was confirmed on the basis of partial sequences of the cytochrome b gene. Even among individuals sampled at the same locality, genetic diversity was surprisingly high. This was interpreted as the result of secondary contact between previously isolated or fragmented populations. The breeding range of the large‐billed reed warbler is likely small and the species’ habitat is under intense pressure from the collection of firewood and fodder. Consequently, the large‐billed reed warbler remains of considerable conservation concern.  相似文献   

15.
雷州半岛红树林湿地鸟类多样性   总被引:1,自引:0,他引:1  
从2000年5月-2003年11月,调查了雷州半岛红树林湿地鸟类.共记录鸟类133种,水鸟和迁徙鸟分别占总记录鸟类数量的81.7%和70.4%.分别有9种、2种、16种和12种鸟被列为中国红皮书保护种、IUCN保护种、CITES保护种和中国国家Ⅱ级保护种;还有63种被列为中日候鸟协定保护种、32种被列为中澳候鸟协定保护种.不同调查地点,鸟类的种类和数量相差较大,高桥鸟类最丰富,记录到83种鸟;五里鸟类种类最少,仅记录到40种鸟,各地鸟类种的相似性很低.环颈鸻(Charadrius alexandrinus)、白腰杓鹬(Numenius arquata)和红嘴鸥(Larus ridibundus)在雷州半岛的种群数量达到国际重要湿地的标准.雷州半岛鸟类种的丰度和多度季节变化明显,冬季种类多、数量丰富,夏季种类少、数量贫乏.冬季和夏季总的鸟类数量(P=0.043)和水鸟数量(P=0.001)差异明显.保护整个沿海红树林湿地是保护雷州半岛红树林湿地鸟类多样性的关键.  相似文献   

16.
Sex biases in distributions of migratory birds during the non‐breeding season are widespread; however, the proximate mechanisms contributing to broad‐scale sex‐ratio variation are not well understood. We analyzed a long‐term winter‐banding dataset in combination with spring migration data from individuals tracked by using geolocators to test three hypotheses for observed variation in sex‐ratios in wintering flocks of snow buntings Plectrophenax nivalis. We quantified relevant weather conditions in winter (temperature, snowfall and snow depth) at each banding site each year and measured body size and condition (fat scores) of individual birds (n > 5500). We also directly measured spring migration distance for 17 individuals by using light‐level geolocators. If the distribution pattern of birds in winter is related to interactions between individual body size and thermoregulation, then larger bodied birds (males) should be found in colder sites (body size hypothesis). Males may also winter closer to breeding grounds to reduce migration distance for early arrival at breeding sites (arrival timing hypothesis). Finally, males may be socially dominant over females, and thus exclude females from high‐quality wintering sites (social dominance hypothesis). We found support for the body size hypothesis, in that colder and snowier weather predicted both larger body size and higher proportions of males banded. Direct tracking revealed that males did not winter significantly closer to their breeding site, despite being slightly further north on average than females from the same breeding population. We found some evidence for social dominance, in that females tended to carry more fat than males, potentially indicating lower habitat quality for females. Global climatic warming may reduce temperature constraints on females and smaller‐bodied males, resulting in broad‐scale changes in distributional patterns. Whether this has repercussions for individual fitness, and therefore population demography, is an important area of future research.  相似文献   

17.
KJELL SJÖBERG 《Ibis》1988,130(2):164-171
A total of 126 flightless adult male Teal was caught in 1982 and 1983 in a moulting area in northern Sweden (63° 53'N). The birds were weighed and the stage of development of their primaries and secondaries measured. During the flightless period, the weight of the birds decreased by an average of 10% in 1982 and 19% in 1983. This weight decrease allows the birds to fly before their primaries and secondaries are full-grown. The weight loss is considered to be an adaptation making it possible, for example, for lighter birds to escape predators sooner after moulting. Birds varied greatly in the dates at which they initiated their flightless period, that is, from the end of June to the end of July. Thus, it is probable that both local birds and birds from distant breeding grounds were present in the moulting area.  相似文献   

18.
Four adult male Asian Houbara Bustards Chlamydotis macqueenii were caught on their breeding grounds in the Gobi Desert of China and tracked by satellite from July 2000 for from 5 months to > 3.5 years. Wintering areas were identified for two individuals, one on the Turkmenistan/Uzbekistan border in the Amur-Darya valley, the second at the Iran/Turkmenistan border. One individual used the same wintering and breeding areas for three consecutive years. Overall departure dates from breeding grounds ranged from 29 September to 14 October, with arrival on wintering quarters from 23 October to 7 November. Birds left their wintering grounds between 2 and 21 March and reached their breeding areas between 11 and 21 April. The mean overall migration distance was 3935 km (sd = ± 229, n  = 9). Houbara Bustards mainly followed steppe areas to migrate avoiding the highest elevations of the Himalayan massif and travelling 267 km/day on average. Pre-breeding migration lasted longer than post-breeding and included more and longer stopovers. The Taukum Desert and Jungar Basin are critical areas for migration of eastern Houbara populations. Breeding range, used for 5.5 months, was 274 km2 (sd = ± 53, n  = 4), whereas wintering range, used for around 4 months a year, was 76 km2 (sd = ± 22, n  = 3). Range use pattern appeared similar for Asian Houbara released in central Saudi Arabia, but differed from the African Houbara Bustard. More investigations are required to determine the effects of food availability and meteorological conditions on the migration pattern and on the use of stopovers by Asian Houbara Bustards.  相似文献   

19.
For migratory birds, it is necessary to estimate annual and overwinter survival rates, identify factors that influence survival, and assess whether survival varies with age and sex if we are to understand population dynamics and thus inform conservation. This study is one of the first to document overwinter and annual survival from the wintering grounds of a declining Afro‐Palaearctic migrant bird, the Whinchat Saxicola rubetra. We monitored a population of marked individuals for which dispersal was low and detectability was high, allowing accurate estimates of survival. Annual survival was at least 52% and did not differ significantly across demographic groups or with habitat characteristics or residency time in the previous winter. Overwinter survival was very high and monthly survival at least 98% at some sites. Although winter residency varied spatially and with age, lower residency did not correlate with reduced annual survival, suggesting occupancy of multiple wintering sites rather than higher winter mortality of individuals with shorter residency. Our results suggest that mortality occurs primarily outside the wintering period, probably during migration, and that wintering conditions have minimal influence on survival. The similarity between survival rates for all age and sex classes when measured on the wintering grounds implies that any difference in survival with age or sex occurs only during the first migration or during the post‐fledging stage, and that selection of wintering habitat, or territory quality, makes little difference to survival in Whinchats. Our findings suggest that the wintering grounds do not limit populations as much as the migratory and breeding stages, with implications for the conservation of declining Afro‐Palaearctic migrants more widely.  相似文献   

20.
No-take zones may protect populations of targeted marine species and restore the integrity of marine ecosystems, but it is unclear whether they benefit top predators that rely on mobile pelagic fishes. In South Africa, foraging effort of breeding African penguins decreased by 30 per cent within three months of closing a 20 km zone to the competing purse-seine fisheries around their largest colony. After the fishing ban, most of the penguins from this island had shifted their feeding effort inside the closed area. Birds breeding at another colony situated 50 km away, whose fishing grounds remained open to fishing, increased their foraging effort during the same period. This demonstrates the immediate benefit of a relatively small no-take zone for a marine top predator relying on pelagic prey. Selecting such small protected areas may be an important first conservation step, minimizing stakeholder conflicts and easing compliance, while ensuring benefit for the ecosystems within these habitats.  相似文献   

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