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1.
Capsule The winter distribution of Golden Plover and Lapwing has shifted east since the mid-1980s, perhaps in response to climate change.

Aims To combine analyses of winter trends on wetlands and flocks on farmland to assess the current status of Golden Plover and Lapwing in one of their main wintering regions.

Methods Winter trends were derived from monthly counts on estuaries and wetlands for the period 1974–2002 (the Wetland Bird Survey). Winter distribution on farmland was assessed using casual records of large flocks and surveys of a stratified random sample of 1-km squares (the Winter Farmland Bird Survey).

Results Regional trends showed a pronounced increase in numbers of both species since 1974 on the east coast, with a smaller increase on the south coast. Numbers in the west and north tended to decline. Flocks on farmland were concentrated in eastern Britain unlike the situation in the 1980s.

Conclusions The winter distribution of Golden Plover and Lapwing has shifted to the east, resulting in large numbers on the east coast and in the arable east of Britain. The implications of this shift, especially in relation to known habitat associations, are discussed.  相似文献   

2.
Regional trends in the populations of waders wintering largely on estuaries were analysed using data collected by the Wetland Bird Survey between the winters of 1969/70 and 1995/96 to assess whether trends seen at the national level were repeated across regions of Britain. Not all were. Over this period, the numbers of seven of the 12 species studied increased in south and southeast England, but remained static or declined in southwest England and south Wales. Possible explanations for this are proposed. Increases in the number of Curlews Numenius arquata in the north and northeast of Scotland occurred after 1981/82, when the species stopped being a legal quarry species. A rapid decline in Oystercatcher Haematopus ostralegus and Knot Calidris canutus numbers in east England after 1988/89 may be linked to a change in the Wash shell-fisheries. Warmer winters may be making it less essential for birds to winter in the milder west of Britain. In two pairs of regions, northeast and southeast Scotland, and in northwest England/north Wales and northeast England, waders showed similar long-term population changes. The long-term population trends of Oystercatchers in the different regions correlate to those of Ringed Plovers Charadrius hiaticula and Knot, while those of Ringed Plovers are very similar to those of Bar-tailed Godwits Limosa lapponica. In some regions of Britain, the population trends of some species varied a lot between sites, a factor that is an important consideration when determining the size and geographical position of regions for future regional indexing. The present separation of regions based on water catchments and geography has given a useful insight into population changes at a finer spatial scale but it could be improved further with added biological input.  相似文献   

3.
The biogeographic history of three cirrhitoid species pairs with east–west allopatric distributions across southern Australia was examined by determining levels of mitochondrial DNA sequence divergence and applying molecular clock calibrations. Similar levels of genetic divergence were observed for Aplodactylus Valenciennes and Goniistius Gill species pairs, but these were more than twice that observed for a Nemadactylus Richardson pair. Molecular clock calibrations suggested divergences occurred during the late Miocene and mid Pliocene, respectively. Given evidence of high dispersal capabilities, the habitat and climatic barriers of the Australian south coast appear too small to have facilitated speciation of the cirrhitoids examined. A mechanism is proposed by which ancestral cirrhitoids were vicariantly isolated into east and west coast populations during periods of climate change. Although Aplodactylus and Goniistius divergences occurred during the same period, separate vicariant events across the Australian north and south coasts are invoked.  相似文献   

4.
Ron W. Summers 《Ostrich》2013,84(2):167-173
Summers, R. W. 1994. The migration patterns of the Purple Sandpiper Calidris maritima. Ostrich 65: 167–173.

The Purple Sandpiper breeds largely in the Arctic, and winters (boreal season) on the rocky shores of the north Atlantic, further north than any other sandpiper. As the populations from Canada, Greenland, Iceland, Svalbard, Norway and Russia differ in wing and bill lengths it is possible to match measurements taken from breeding birds with samples of birds caught in winter. Ringing recoveries, especially from colour marked birds, have also helped to determine migration routes and wintering areas. Four populations move to the nearest ice-free coast. Two populations move south of the nearest ice-free coast, being replaced by larger birds from a more northerly population (“chain migration”). Only the north Canadian population is believed to migrate a long distance, “leap-frogging” other winter populations. These patterns are discussed in relation to theories for the migration patterns of waders.  相似文献   

5.
The relationship between weather and wader distributions on non-estuarine coasts is described and used to predict how future wader distributions may respond to climate change. The distributions of eight out of nine species of wader commonly wintering on the non-estuarine coasts of Britain altered between two similar surveys, in 1984/85 and 1997/98, that covered 78% and 38% of Britain's 12 594 km of non-estuarine coastline, respectively. These eight species moved at least in part either eastwards along the winter isotherms or northwards. These changes in distribution broadly coincide with a distributional shift towards the species' respective breeding grounds and are correlated with the local winter weather over the period: increasingly mild extreme temperatures and changes in mean rainfall, mean wind speed and wind-chill. Based on the scenarios for Britain's climate in 2020 and 2080, it is predicted that the distributions of the waders will move away from the west. The non-estuarine coasts of Britain hold particularly high proportions of the international flyway populations of Ringed Plover Charadrius hiaticula , Sanderling Calidris alba , Purple Sandpiper Calidris maritima and Ruddy Turnstone Arenaria interpres that are all expected to show continuing decline to 2080. Overwintering waders appear to be good indicators of the effects of climate change.  相似文献   

6.
Drosophila melanogaster is postulated to have colonized North America in the past several 100 years in two waves. Flies from Europe colonized the east coast United States while flies from Africa inhabited the Caribbean, which if true, make the south‐east US and Caribbean Islands a secondary contact zone for African and European D. melanogaster. This scenario has been proposed based on phenotypes and limited genetic data. In our study, we have sequenced individual whole genomes of flies from populations in the south‐east US and Caribbean Islands and examined these populations in conjunction with population sequences from the west coast US, Africa, and Europe. We find that west coast US populations are closely related to the European population, likely reflecting a rapid westward expansion upon first settlements into North America. We also find genomic evidence of African and European admixture in south‐east US and Caribbean populations, with a clinal pattern of decreasing proportions of African ancestry with higher latitude. Our genomic analysis of D. melanogaster populations from the south‐east US and Caribbean Islands provides more evidence for the Caribbean Islands as the source of previously reported novel African alleles found in other east coast US populations. We also find the border between the south‐east US and the Caribbean island to be the admixture hot zone where distinctly African‐like Caribbean flies become genomically more similar to European‐like south‐east US flies. Our findings have important implications for previous studies examining the generation of east coast US clines via selection.  相似文献   

7.
Global climate changes during the Cenozoic (65.5–0 Ma) caused major biological range shifts and extinctions. In northern Europe, for example, a pattern of few endemics and the dominance of wide‐ranging species is thought to have been determined by the Pleistocene (2.59–0.01 Ma) glaciations. This study, in contrast, reveals an ancient subsurface fauna endemic to Britain and Ireland. Using a Bayesian phylogenetic approach, we found that two species of stygobitic invertebrates (genus Niphargus) have not only survived the entire Pleistocene in refugia but have persisted for at least 19.5 million years. Other Niphargus species form distinct cryptic taxa that diverged from their nearest continental relative between 5.6 and 1.0 Ma. The study also reveals an unusual biogeographical pattern in the Niphargus genus. It originated in north‐west Europe approximately 87 Ma and underwent a gradual range expansion. Phylogenetic diversity and species age are highest in north‐west Europe, suggesting resilience to extreme climate change and strongly contrasting the patterns seen in surface fauna. However, species diversity is highest in south‐east Europe, indicating that once the genus spread to these areas (approximately 25 Ma), geomorphological and climatic conditions enabled much higher diversification. Our study highlights that groundwater ecosystems provide an important contribution to biodiversity and offers insight into the interactions between biological and climatic processes.  相似文献   

8.
R. W. Rand 《Ostrich》2013,84(2):72-76
Summers, R.W. &; Kaletja-Summers, B. 1996. Seasonal use of sandflats and saltmarshes by waders at low and high tide at Langebaan Lagoon, South Africa. Ostrich 67:72-79.

Migrant and resident waders were counted on sandflats and saltmarshes at low and high tide during two summers (197576 and 1976–77) and two winters (1975 and 1976) at Langebaan Lagoon. Intertidal sandflats supported higher densities of waders than saltmarshes at low tide in summer (18.7 and 17.2 waders ha' on sandflats compared with 0.4 and 2.9 waders ha' on saltmarshes) and winter (0.9 and 3.1 compared with 0.6 and 1.9 waders ha I for the two years). At high tide, most waders moved onto saltmarshes, attaining densities of 70.4 and 53.6 waders ha' in the two summers, and 5.7 and 15.6 birds ha' in the two winters. Resident waders comprised 0.3 and 0.8% of the wader community in the two summers and 41 and 5% in the two winters. They were also at higher densities in winter than in summer. The composition of wader communities on the different sandflats varied little in summer and Curlew Sandpipers were the most abundant species on all sandflats. Minor variations in species composition included proportionately more Turnstones at the mouth of the lagoon, more Sanderlings and Whimbrels in the mid sections and more Terek Sandpipers, Greenshanks and Curlews in the upper part. Larger percentages of waders were foraging on the sandflats at low tide in both summer (96 and 92% for the two summers) and winter (85 and 94% for the two winters) compared with the saltmarshes (73 and 79% in the two summers and 60 and 81% in the two winters). A larger proportion of small waders were foraging on sandflats at low tide compared with large waders. At high tide on the saltmarshes, the percent of foraging birds was lower in summer (29% for both summers) than in winter (36 and 78% for the two winters), perhaps reflecting seasonal changes in energy requirements.  相似文献   

9.
There is increasing evidence that climate change shifts species distributions towards poles and mountain tops. However, most studies are based on presence–absence data, and either abundance or the observation effort has rarely been measured. In addition, hardly any studies have investigated the direction of shifts and factors affecting them. Here, we show using count data on a 1000 km south–north gradient in Finland, that between 1970–1989 and 2000–2012, 128 bird species shifted their densities, on average, 37 km towards the north north‐east. The species‐specific directions of the shifts in density were significantly explained by migration behaviour and habitat type. Although the temperatures have also moved on average towards the north north‐east (186 km), the species‐specific directions of the shifts in density and temperature did not correlate due to high variation in density shifts. Findings highlight that climate change is unlikely the only driver of the direction of species density shifts, but species‐specific characteristics and human land‐use practices are also influencing the direction. Furthermore, the alarming results show that former climatic conditions in the north‐west corner of Finland have already moved out of the country. This highlights the need for an international approach in research and conservation actions to mitigate the impacts of climate change.  相似文献   

10.
Mammals of south-east Asian islands and their Late Pleistocene environments   总被引:3,自引:1,他引:2  
Aim The environments that existed in south‐east Asian islands during the last glacial are poorly known, limiting our understanding of mammalian biogeography in the region. The objective of this research is to investigate the ecological characteristics of mammal faunas on small islands, and to see whether the habitat requirements of the species in those faunas can be used to deduct the vegetation types that existed on islands before becoming isolated by rising sea levels. Location The maps presented here cover the small islands of tropical south‐east Asia, including the Burmese, Thai and Cambodian islands in the north, the islands off the coast of west Sumatra in the west, the islands around Java in the south, and the islands off the east coast of Borneo in the east, including the Philippine islands of Palawan and those in the Sulu Archipelago. Methods The presence records of mammal species on 215 small islands in the region were compiled, and the habitat requirements for each of these species was assessed (species that had probably been introduced by humans were excluded from the analysis). For each island location (longitude and latitude), maximum altitude of the island, total area, depth to nearest land, distance to nearest island, and distance to nearest mainland were assessed. Geographical and statistical analyses were used to investigate patterns of mammalian habitat requirements. Results The geographical analysis showed that forest‐dependent species, i.e. species that are only found in primary forest (lowland and mountainous), appear to be concentrated on islands off west Sumatra, in the Lingga and Riau Archipelagos, around Palawan, and around Bunguran Island; they are absent mostly from the islands of the Java Sea, those off the east coast of eastern Borneo, from most islands in the Sunda Strait, several islands in the northern South China Sea, and from all islands off the west coast of the Malay/Thai Peninsula and in the Gulf of Thailand. Species that generally occur outside primary forest, that is those in secondary forest, gardens, plantations and open areas mostly occurred on islands where the forest‐dependent species were absent. The statistical analysis showed that latitude and size of islands were important factors that determined the absence and presence of forest‐dependent species on small islands. Main conclusions The data suggest that during the last glacial there were several areas in the Sundaic region that remained forest covered: west of Sumatra, north‐west of Borneo, the Malacca Straits and around Palawan. Other areas may have been covered by more open vegetation types like tree savanna, or open deciduous forest: on and to the east of the Malay/Thai Peninsula, the Java Sea area, including the Sunda Strait, and eastern Borneo.  相似文献   

11.
Aim Changing conditions across spatial gradients are primary determinants of biotic regions, local habitats, and distributional edges. We investigate how a climatic gradient and edaphic mosaic interact as multi‐scale drivers of spatial patterns in scarabaeine dung beetles. The patterns are tested for congruency with ecoregion and floral boundaries over the same gradient, as responses to physical factors often differ among higher taxa. Location Southern Africa and the Nama Karoo–Kalahari ecotone, Northern Cape, South Africa. Methods Data consisted of the climatic distributions of 104 species and their abundances at 223 sites in two ecoregions/floral biomes, four bioregions, and 13 vegetation units. Factor analyses determined the biogeographical composition of the species, and regional‐ to local‐scale patterns in species abundance structure. Hierarchical analysis of oblique factors determined the proportional contribution of spatial variance to patterns. One‐way anova was used to test for significant separation of patterns along factor axes. Stepwise multiple regression was used to determine correlations of five physical attributes with species richness, Shannon‐Wiener diversity, and factor loadings for the study sites. Results Four biogeographical influences overlap in the study region, although rank contribution declines from south‐west arid through north‐east savanna to widespread and south‐east highland taxa. Species abundance structure comprises five subregional patterns, two centred to the north‐east (Kalahari, Isolated Kalahari Dune) dominated by Kalahari influence, and three to the south‐west (Nama Karoo subdivisions: Bushmanland, ‘Upper’, ‘Stony Prieska’) dominated by south‐west arid influence. Kalahari deep sands are characterized especially by a warmer, moister climate, whereas the Nama Karoo mosaic of deep or stony soils is characterized especially by north‐west aridity (Bushmanland), south‐east cooler temperatures (‘Upper’), or excessively stony soils (‘Stony Prieska’). Four of the subregional patterns each comprised three localized patterns related primarily to relative stoniness, edge effects from geographical position, or incidence of rainfall. Species richness and diversity declined with decreasing rainfall and increasing stoniness. Main conclusions Climatic and edaphic factors are important multi‐scale determinants of spatial patterns in dung beetle assemblage structure, with edaphic factors becoming more important at local spatial scales. The patterns are roughly congruent with the Kalahari Savanna–Nama Karoo ecotone at the floral biome or ecoregion scale, but show limited coincidence with finer‐scale floral classification.  相似文献   

12.
The winter‐rainfall region of southern Africa, covered largely by the fynbos and succulent karoo biomes, harbours the world's greatest concentration of geophyte species. Species diversity is greatest in the south‐west, where more than 500 species co‐occur in one quarter‐degree square; in the south‐east the values are generally around 100, and in the arid north‐west, always less than 50 (more often less than 10). In at least three species‐rich genera (Moraea, Eriospermum and Oxalis), the size of storage organs (bulbs, corms, tubers) varies inversely, with the largest average values occurring in the species‐poorer areas — both in the north‐western, and in the south‐eastern parts of the region. This negative correlation between average storage organ size and species diversity is, however, only observed at relatively large spatial scales, which suggests that there is no direct relationship between storage organ size and species diversity. More likely, both these measures are driven by winter rainfall amount and reliability, both of which peak in the south‐western Cape. We suggest that reliable winter rainfall makes large storage organs unnecessary and depresses extinction rates, thus leading to the accumulation of species.  相似文献   

13.
Available data on species distributions and endemicity were compiled and examined for 11 groups of South African marine invertebrates (2533 species). For five groups species richness adhered to a well‐documented pattern, increasing from west to east, but for the other groups species richness was highest along the south coast. Endemicity was generally highest along the south coast, and lowest along the east coast. The data base was then analysed using several types of complementarity analyses, each producing a minimum set of potential reserve areas, which cumulatively represent all invertebrate species analysed. Approaches based solely on rarity, species richness and endemicity demonstrated individual biases, suggesting a need to combine all three interests. Combining the three techniques produced similar results to the individual analyses, showing conservation priorities to be highest along the east coast. Specifically, the areas of Port Elizabeth and Durban were ranked high in all analyses. Consistently, a total of 16 sites was necessary to represent all species analysed. Comparisons with similar analyses on fish and seaweeds revealed similar findings. Existing invertebrate records were shown to be biased towards centres of high sampling activity, demonstrating a need of future sampling attention in under‐represented areas.  相似文献   

14.
Aim Over the past three decades, evidence has been growing that many Afro‐Palaearctic migratory bird populations have suffered sustained and severe declines. As causes of these declines exist across both the breeding and non‐breeding season, identifying potential drivers of population change is complex. In order to explore the roles of changes in regional and local environmental conditions on population change, we examine spatial and temporal variation in population trajectories of one of Europe’s most abundant Afro‐Palaearctic summer migrants, the willow warbler, Phylloscopus trochilus. Location Britain and Ireland. Methods We use national survey data from Britain and Ireland (BBS: BTO/RSPB/JNCC Breeding Bird Survey and CBS: BWI/NPWS/Heritage Council Countryside Breeding Survey) from 1994 to 2006 to model the spatial and temporal variation in willow warbler population trends. Results Across Britain and Ireland, population trends follow a gradient from sharp declines in the south and east of England to shallow declines and/or slight increases in parts of north and west England, across Scotland and Ireland. Decreasing the spatial scale of analysis reveals variation in both the rate and spatial extent of population change within central England and the majority of Scotland. The rates of population change also vary temporally; declines in the south of England are shallower now than at the start of the time series, whereas populations further north in Britain have undergone periods of increase and decline. Main conclusion These patterns suggest that regional‐scale drivers, such as changing climatic conditions, and local‐scale processes, such as habitat change, are interacting to produce spatially variable population trends. We discuss the potential mechanisms underlying these interactions and the challenges in addressing such changes at scales relevant to migratory species.  相似文献   

15.
The diets of slender snipefish Macroramphosus gracilis, longspine snipefish Macroramphosus scolopax and boarfish Capros aper, three very abundant species on the Portuguese coast, were studied from samples collected between July 2002 and April 2003. Variations in the diet with fish size, season and area, as well as diet overlap and diversity, are explored in this study. The diets of slender snipefish and boarfish were mainly composed of copepods, with the main prey being Temora spp. and Calanus spp., respectively. Mysid shrimps were the most important food item in the diet of longspine snipefish. During the summer season, when the availability of different prey items was highest, the two species of snipefish and the boarfish fed on different prey. Temora spp. were the most important prey in the stomachs of slender snipefish in the summer on the south‐west coast, while Calanus spp. started appearing in the stomachs of boarfish in the spring in the north, increasing their abundance in the summer on the south and south‐west coasts. The abundance of mysids appeared to increase in the autumn on the south‐west coast, being at that time an important food item for both longspine snipefish and boarfish. For slender snipefish and boarfish, the differences in stomach species diversity were explained firstly by the season and then by the area and fish size. For longspine snipefish, the area did not explain the species diversity variability, season being the first variable determining the differences. Of all three species, slender snipefish was the one with highest diversity of stomach contents, particularly in spring and summer on the north and south‐west coasts. Diet overlap between species was very low. No predation on eggs and larval stages of fishes was found for any of these fish species. This work is the first to address the diets of snipefish species and boarfish in the south‐east North Atlantic, in a large spatio‐temporal coverage. These species are important prey for many commercial species on the Portuguese coast and, given their abundance, may have a great impact on zooplankton communities, thus assuming a pivotal position in marine food webs.  相似文献   

16.
Climate change is predicted to cause changes in species distributions and several studies report margin range shifts in some species. However, the reported changes rarely concern a species' entire distribution and are not always linked to climate change. Here, we demonstrate strong north‐eastwards shifts in the centres of gravity of the entire wintering range of three common waterbird species along the North‐West Europe flyway during the past three decades. These shifts correlate with an increase of 3.8 °C in early winter temperature in the north‐eastern part of the wintering areas, where bird abundance increased exponentially, corresponding with decreases in abundance at the south‐western margin of the wintering ranges. This confirms the need to re‐evaluate conservation site safeguard networks and associated biodiversity monitoring along the flyway, as new important wintering areas are established further north and east, and highlights the general urgency of conservation planning in a changing world. Range shifts in wintering waterbirds may also affect hunting pressure, which may alter bag sizes and lead to population‐level consequences.  相似文献   

17.
Syroechkovski, E.E. Jr. & Lappo, E.G. 1994. Migration phenology of waders (Charadrii) on the Taimyr Peninsula, northern Russia. Ostrich 65:181–190.

Palearctic waders from six flyways breed on the Taimyr Peninsula. They can be observed in winter from Europe to South Africa and Australia. The interval between pre- and postbreeding movements of waders in Taimyr is short. Breeding waders, which spend from 50–70 days on the tundra have a arrival tight schedule, dependent mostly on weather conditions. Most species arrive during the first half of June, with the more northern areas occupied several days later than southern areas. However, Turnstone, Dunlin and Curlew Sandpiper arrive in the optimal art of their breeding ground first, and subsequently occupy sup-optimal areas to the north and the south. In autumn waders migrate in small groups across the tundra. The schedule depends greatly on the breeding success of the year. Large numbers of Ruff and Bartailed Godwit concentrate in high arctic areas, 300–500 km north of their breeding grounds, before commencing southwards migration. Autumn concentrations of waders in intertidal areas are rare.  相似文献   

18.
Increasing temperatures are predicted to have profound effects on montane ecosystems. In tropical forests, biotic attrition may reduce lowland diversity if losses of species due to upslope range shifts are not matched by influxes of warmer‐adapted species, either because there are none or their dispersal is impeded. Australian rainforests consist of a north–south chain of patches, broken by dry corridors that are barriers to the dispersal of rainforest species. These rainforests have repeatedly contracted and expanded during Quaternary glacial cycles. Many lowland rainforests are expansions since the Last Glacial Maximum and may, therefore, show a signal of historical biotic attrition. We surveyed ants from replicated sites along three rainforest elevational transects in eastern Australia spanning 200 to 1200 m a.s.l. and nearly 14° of latitude. We examined elevational patterns of ant diversity and if there was possible evidence of lowland biotic attrition. Each transect was in a different biogeographic region; the Australian Wet Tropics (16.3°S), the central Queensland coast (21.1°S) and subtropical south‐eastern Queensland (28.1°S). We calculated ant species density (mean species per site) and species richness (estimated number of species by incorporating site‐to‐site species turnover) within elevational bands. Ant species density showed no signal of lowland attrition and was high at low and mid‐elevations and declined only at high elevations at all transects. Similarly, estimated species richness showed no evidence of lowland attrition in the Wet Tropics and subtropical south‐east Queensland; species richness peaked at low elevations and declined monotonically with increasing elevation. Persistence of lowland rainforest refugia in the Wet Tropics during the Last Glacial Maximum and latitudinal range shifts of ants in subtropical rainforests during the Holocene climatic optimum may have counteracted lowland biotic attrition. In central Queensland, however, estimated richness was similar in the lowlands and mid‐elevations, and few ant species were indicative of lower elevations. This may reflect historical biotic attrition due perhaps to a lack of lowland glacial refugia and the isolation of this region by a dry forest barrier to the north.  相似文献   

19.
Many species of fishes along the east coast of the United States have complex life histories, especially those that move over hundreds of kilometers across ocean and estuarine habitats. To further unravel the life history of one of these, the speckled worm eel, Myrophis punctatus we examined samples from extensive time series and discrete samples collected in the ocean and estuaries between Florida and Massachusetts. We now surmise spawning occurs between fall and early winter in the ocean south of Cape Hatteras, North Carolina and in the vicinity of the Bahamas. The pelagic leptocephalus larvae (10?C80 mm Total Length [TL]) are transported north in the Gulf Stream and across the continental shelf to arrive at estuarine inlets at ages of 53 ?C 110 days. Their estuarine immigration and abundance varies along the east coast, with higher levels occurring at inlets in South Carolina (North Inlet), and North Carolina (Beaufort Inlet), during the winter and early spring. Much lower abundances occur in New Jersey (Little Egg Inlet) in winter and spring and again in the summer. These ingressing individuals were euryodontic leptocephali and metamorphic stages and were shrinking to lengths of 76?C52 mm TL as these stages progressed. Metamorphic individuals and glass eels subsequently settle and burrow in estuarine sediments, as do all subsequent stages, and thereby become relatively unavailable to many sampling gears. In estuaries they attained sizes up to 440 mm TL. Later, they presumably enter the ocean to spawn because that is where the smallest larvae are found.  相似文献   

20.
N. Huin  T.H. Sparks 《Bird Study》2013,60(1):22-31
Data on the arrival dates of Cuckoo, Nightingale and Spotted Flycatcher published in the Royal Meteorological Society phenological reports are presented. From these records, contour maps showing the pattern of progression through Britain were produced for each species. Of the three species, the Cuckoo arrived earliest and progressed the slowest from south to north; it entered Britain by the southeast. The Nightingale arrived later than the Cuckoo and progressed along a southeast to northwest axis. The Spotted Flycatcher was the last to arrive, but progressed with the greatest speed from south to north. Arrival dates of all three species were influenced by the temperature in southern Europe in the month preceding arrival in Britain and by the difference between these temperatures in southern Europe and those a month later in France or Britain. The diminishing population levels of Nightingale may have had a masking effect on its arrival dates. Although mean arrival dates for the three species were strongly influenced by temperature, long-term trend effects should be interpreted with caution as other factors also influence mean arrival dates.  相似文献   

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