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1.
Differences in the ability of salivary proteins from Scandinavian and North American moose (Alces alces) to bind tannins from various preferred food plant sources were studied. Both Scandinavian and North American moose produce a salivary tannin-binding protein which binds only condensed tannins common in their diet. The tannins of winter-browsed stems of Pinus sylvestris and Salix pentandra were more effectively bound by salivary tannin-binding protein from North American moose than by those from Scandinavian moose. Tannins of P. sylvestris and S. pentandra stems were also more effective binding agents than tannins from S. caprea and Betula species. The interactions between salivary tannin-binding protein and plant tannins may be one factor affecting food plant choice of moose. The chemical and biochemical characteristics of plant tannins and the ability of salivary tannin-binding proteins to react with tannins should be taken into account in diet selection.  相似文献   

2.
The exceedingly high mortality rates generally associated with artificially raising neonatal moose frequently can be attributed to improper nutritional management and poor husbandry techniques. Dietary-induced diarrhea caused by inappropriate milk replacers is common in moose calves raised in captivity. To avoid diarrhea, calves are often purposefully underfed, resulting in poor growth rates during the first 4 weeks when maternally raised calves rely on milk as their sole energy source. We developed a milk formula and feeding protocol modeled after milk composition and neonatal intake rates measured in maternally raised moose calves. Growth rates for bottle-raised calves during the first 30 days (752 g/day) were similar to maternally raised calves and at least twice that of most previously published bottle-raising efforts. No diet-induced gastrointestinal disorders were encountered, and all calves were successfully weaned and survived their first year. Zoo Biol 16:495–503, 1997. © 1997 Wiley-Liss, Inc.  相似文献   

3.
A review of the Holocene records of the osprey (Pandion haliaetus) in Central Europe indicates an immigration around 10,000 years BP at the latest. During the middle Holocene—9,000–5,000 years BP—the species seems to have been common in the south-western Baltic region and perhaps also in Switzerland, but scarce in the rest of Central Europe. After a complete lack of osprey remains for nearly 4,000 years up to medieval times, a few records again suggest a sporadic distribution of this species in the south-western Baltic. In early modern times, the osprey recolonised north-eastern Germany and, during the nineteenth and the first decades of the twentieth century, bred in colony-like densities. Because of relentless persecution and, later, contamination with pesticides, osprey populations collapsed. Recently, the Central European populations have been slowly increasing again. The significance of the subfossil findings is discussed and possible reasons for their scarcity are outlined.  相似文献   

4.
1. Mech et al . (1987) documented cumulative, negative effects of previous winters' snow on rates of population increase in moose ( Alces alces ) and white-tailed deer ( Odocoileus virginianus ), but noted no effect of predation by wolves ( Canis lupus ). Those results were contested by Messier (1991), who analysed smoothed versions of the original abundance data and reported no effect of snow accumulation on population dynamics of either species, but strong effects of wolf predation and food competition.
2. McRoberts, Mech & Peterson (1995) contended that the conclusions reached by Messier (1991) were an artefact of the use of smoothed data. In a subsequent re-analysis of the smoothed data, Messier (1995) argued that the lack of an effect of snow after one year precluded the potential for a cumulative effect beyond one year.
3. We re-analysed original and smoothed data on dynamics of moose and white-tailed deer densities using the same methods as Mech et al . (1987) and Messier (1991), but we used a measure of global climatic fluctuation, the North Atlantic Oscillation (NAO) index. The NAO is the atmospheric process determining most interannual variation in snowfall and winter temperatures in northern latitudes, and its phases drive decadal trends in wintertime precipitation.
4. We observed that rates of increase of moose and white-tailed deer in both the original and smoothed data were influenced by global climatic fluctuation at 2- and 3-year lags, as well as by delayed density-dependent feedback and wolf predation.  相似文献   

5.
Moose, Alces alces, occur naturally throughout most of Canada but successful introductions of known numbers of animals have been made to the islands of Newfoundland and Cape Breton. Five microsatellite loci were used to investigate the population genetic structure and any change in genetic variability due to founder events of moose in Canada. Comparisons of allele frequencies for moose from 11 regions of the country suggested that there are at least seven genetically distinct populations (P < 0.05) in North America, namely Alberta, eastern Ontario, New Brunswick, Cape Breton, Labrador, western Newfoundland, and the Avalon Peninsula of Newfoundland. The average population heterozygosity was approximately 33% (range from 22 to 41%). UPGMA analysis of Nei's genetic distances produced phenograms similar to what would be expected when geographical location and population history are considered. The loss of heterozygosity due to a single founder event (n = 3; two introductions and a natural colonization) ranged from 14 to 30%, and the cumulative loss of heterozygosity due to two successive founder events (an introduction followed by a natural colonization) was 46%. In these examples loss of genetic variability has not been associated with any known phenotypic deviances, suggesting that populations may be established from a small number of founders. However, the viability of these founded populations over evolutionary timescales cannot be determined and is highly dependent upon chance.  相似文献   

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On the basis of distribution maps showing the first pollen occurrences in the Holocene of the well-known climate indicators Hedera, Ilex and Viscum as well as data for Corylus, a series of maps have been prepared that show summer and winter isotherms at various time intervals during the Holocene. From these maps climate curves for Amsterdam, the Netherlands have been set out. These were compared with curves for the Eemian at the same site. In both of these warm periods there is evidence for increased seasonality in the early phases which were relatively continental. Changes in insolation could account for such differences. Summer optima occurred earlier than winter optima. Changes in land-sea distribution are important, especially with regard to the patterns in winter climate. During the latter half of the Eemian, the climate was distinctly more oceanic than in the Holocene. Early in the Holocene, an influx of warm ocean water resulted in higher winter temperatures in the Gulf of Biscay, the Irish Sea, and areas east of Skagerrak-Kattegat. Temperature decline after the climatic optimum was greatest in the north, i.e. at 60°N, where a depression in the order of 2°C in summer and 2–3°C in winter occurred. Temperature decline was less farther south, i.e. at ca. 50°N, where a distinct west-east gradient in temperature change can be observed.  相似文献   

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Schmitt M  Rönn T 《ZooKeys》2011,(157):131-158
A comparison of the geographical distribution patterns of 647 species of Chrysomelidae in Central Europe revealed 13 types of distribution: (1) widely distributed, (2) southern, (3) southeastern, (4) southwestern, (5) northern, (6) eastern, (7) south east quarter, (8) south west quarter, (9) fragmented, (10) montane, (11) subalpine & alpine, (12) scattered, (13) unusual, and irregular patterns produced by insufficient data. Some of these distributions are trivial (e. g. northern, eastern, etc., alpine) but others are surprising. Some cannot be explained, e. g. the remarkable gaps in the distribution of Chrysolina limbata (Fabricius, 1775) and in Aphthona nonstriata (Goeze, 1777). Although our 63.000 records are necessarily tentative, we found that the distribution maps from these data reflect in many cases the common knowledge on the occurrence of leaf beetles in specific areas.  相似文献   

12.
The aim of this research was to estimate the former below- and aboveground biomass during the Last Pleniglacial (22,000 cal yr BP) and during the Holocene climatic optimum, the Atlantic Period (7,000 cal yr BP). Vegetation distributions and soil conditions during these periods were reconstructed according to published literature. Using the present-day bio-masses of similar (but not identical) vegetation and soil types as analogues, estimates of the terrestrial biomass were made for 22,000 and 7,000 cal yr BP. Biomass was low during the Pleniglacial, representing only 5.0 to 12.5 Gt. This reflects weak soil development under cold climatic conditions, combined with soil erosion due to severe frost and strong wind. The results are compared with other biomass reconstructions for the Pleniglacial. The values for terrestrial biomass of the Pleniglacial presented in this paper are much lower than the results of the various studies for this time slice. These differences are likely to be related to the method applied. Biomass was high during the Holocene climatic optimum around 7,000 cal yr BP, representing 261 to 325 Gt compared to 232 to 273 Gt in the present potential situation and 165 to 197 Gt in the present-day real situation. This reflects intensive soil development under warm and moist conditions during the climatic optimum of the Holocene. These results demonstrate the fluctuation of C-content in terrestrial ecosystems since the Last Glacial Maximum on the European continent.  相似文献   

13.
In the geological research of the Holocene coastal deposits of The Netherlands, diatoms are used to reconstruct the sedimentary facies, palaeo-tide levels and salinity gradients during the deposition of the sediments. In this paper, the results of diatom research from 4 borings, taken from the early and middle Holocene deposits of central North Holland are presented. The oldest marine influenced sediments in the area are the deposits of the ‘Velsen layer’, a clay layer rich in organic matter and deposited about 8000–700014C years before present (BP) at a depth of 20–12 m below present mean sea-level. This clay layer was formed in a shallow, permanently submerged environment with a limited tidal influence (lagoonal or pond-like conditions). The salinity changed from brackish/freshwater to marine/brackish. The younger sandy and clayey sediments, formed about 7000–4500 BP at a depth of 16–3 m below present mean sea-level, are classified as ‘tidal channel’ and ‘interchannel’ deposits. It is argued, on the base of both diatom and non-diatom criteria, that the lower and middle parts of the interchannel deposits in the central area of the palaeo-tidal basin of North Holland were formed in a subtidal environment. The upper part of the interchannel deposits and the deposits at the fringe of the North Holland tidal basin were formed in the intertidal zone or, at the fringe of the basin, even in the supratidal zone. The salinity in the North Holland tidal basin during the sedimentation of the tidal channel and interchannel deposits was marine/brackish to marine. This study indicates that diatoms, besides their palaeoecological applications, have chronostratigraphical significance (on a regional scale). The diatomsCymatosira belgica andActinoptychus splendens appear to be a useful (eco)stratigraphical marker in the Holocene coastal deposits of The Netherlands and Belgium.  相似文献   

14.
Igor Hudec 《Hydrobiologia》1990,190(1):33-42
Moina weismanni Ishikawa is reported from Czechoslovakia, Hungary, and Yugoslavia. The species was formerly synonymized with Moina micrura Kurz, based on parthenogenotic females. In both species, parthenogenetic females have a characteristic postabdomen, antennules (characters formerly regarded as typical for a variety of M. micrura), and ephippium. Wales are quite different. Examined populations of both species are similar in length-to-width ratio. M. weismanni is typical for small, eutrophic but permanent, and for large temporary water bodies. M. micrura is restricted to the plankton.  相似文献   

15.
Recent, high-resolution palaeoecological records are changing the traditional picture of post-glacial vegetation succession in the Iberian Peninsula. In addition to the influence of Lateglacial and Early Holocene climatic changes, other factors are critical in the course of vegetation development and we observe strong regional differences. The floristic composition, location and structure of glacial tree populations and communities may have been primary causes of vegetation development. Refugial populations in the Baetic cordilleras would have been a source, but not the only one, for the early Lateglacial oak expansions. From Mid to Late Holocene, inertial, resilient, and rapid responses of vegetation to climatic change are described, and regional differences in the response are stressed. The role of fire, pastoralism, agriculture, and other anthropogenic disturbances (such as mining), during the Copper, Bronze, Iberian, and Roman times, is analysed. The implications of ecological transitions in cultural changes, especially when they occur as societal collapses, are discussed.  相似文献   

16.
  • 1 The North African–Asian lion subgroup, which is composed of two subspecies, the Barbary lion, Panthera leo leo, and the Asian lion, P. l. persica, was nearly exterminated during the last centuries. The remaining free‐ranging population of Asian lions consists of c. 350 animals in India. The Barbary lion subsists as captive animals in zoos or circuses, all of which originate from the Moroccan Royal Collection. There have been multiple genetic hybridizations with sub‐Saharan lions.
  • 2 Several incomplete distribution maps of the past occupation of lions were proposed in the literature. I examine the distribution of these lions with the help of a larger database, extracted from zoological, archaeological and historical reports. Some records are however not completely reliable. Data were collected over a long period of time (from the Epipaleolithic to the modern times) in Eurasia, North Africa and the Arabian Peninsula.
  • 3 Dispersal took place in latitudes as far south as 15°N (Yemen) to 18°N (Mali; Chad) and as far north as 45–48°N (Bulgaria); and to longitudes as far west as 5.57°W (Morocco) and as far east as 84°E (India). Expansion was probably constrained by natural ecological factors northwards (higher seasonality, harsher winters) and southwards (extension of aridity after 3000 BP). At latitudes between 40 and 43°N, lions seem to have become a permanent part of the fauna during 6–8 millennia.
  • 4 Lions were brought to extinction by humans through hunting, captures for exhibition in zoos and by the associated natural fragmentation of wild populations. The dates at which extinction took place varied greatly according to the geographical sites: 3000 BC for temperate Europe; 1000 BC in the south of Greece; 12–13th century in the Near East, Arabian Peninsula, Trans‐Caucasia or north of Afghanistan; and 19–20th century for North Africa, the Middle East and India.
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17.
Using ancient DNA sequences of subfossil European pond turtles ( Emys orbicularis ) from Britain, Central and North Europe and accelerator mass spectrometry radiocarbon dating for turtle remains from most Swedish sites, we provide evidence for a Holocene range expansion of the pond turtle from the southeastern Balkans into Britain, Central Europe and Scandinavia, according to the 'grasshopper pattern' of Hewitt. Northeastern Europe and adjacent Asia were colonized from another refuge located further east. With increasing annual mean temperatures, pond turtles reached southern Sweden approximately 9800 years ago. Until approximately 5500 years ago, rising temperatures facilitated a further range expansion up to Östergötland, Sweden (approximately 58°30'N). However, around 5500 years ago pond turtle records suddenly terminate in Sweden, some 1500 years before the Holocene thermal maximum ended in Scandinavia and distinctly earlier than previously thought. This extinction coincides with a temporary cooling oscillation during the Holocene thermal maximum and is likely related to lower summer temperatures deteriorating reproductive success. Although climatic conditions improved later again, recolonization of Sweden from southern source populations was prevented by the Holocene submergence of the previous land connection via the Danish Straits that occurred approximately 8500 years ago.  相似文献   

18.
The introduction and early spread of common ragweed (Ambrosia artemisiifolia L.) in Central and Eastern Europe were reconstructed based on a study of all herbarium specimens of common ragweed deposited at six herbaria in Austria, Hungary and Serbia. More than 450 specimens were examined and the oldest ones, collected from 1907 to 1927, were used to map the historical spread of this highly allergenic invasive weed in this region. The herbarium records back-date the first known introduction of this noxious weed to Central and Eastern Europe as well as its early spread on the Danube-Tisza Plain, and in the North-Eastern part of Hungary. The data also confirm that the introduction of common ragweed to Central and Eastern Europe took place later than its introduction to the Western part of the continent.  相似文献   

19.
Baldellia ranunculoides (L.) Parl. (Alismataceae) is a taxonomically problematic aquatic plant with an historically ill-defined distribution and global conservation status. This paper finds morphological, ecological and molecular evidence for two distinct taxa, probably best described as subspecies: (1) B. ranunculoides subsp. ranunculoides and (2) B. ranunculoides subsp. repens and provides detailed distribution data on their overlapping range, in different habitats, across the cool, high rainfall areas of western Europe and west Mediterranean. The two subspecies are amongst the relatively large number of threatened European and north Africa aquatic plants and this paper provides a systematic review of their relative conservation pressures and management needs, with particular emphasis on the status of both taxa in central Europe. Other observations indicate probable evolutionary relationships within B. ranunculoides s.l. and its associated taxa and the review points out where these and other research topics could potentially be pursued.  相似文献   

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