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51.
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53.
Pair-wise preference experiments were used to reveal predator discrimination by four tit species wintering in the Czech Republic.
The reactions of the tits to a more dangerous predator (sparrowhawk) and a less dangerous (kestrel) one were compared. The
number of visits to a feeder with a predator present expressed the perceived dangerousness of the predator. The tits' behaviour
towards the feeders was in agreement with predictions, according to dynamic risk assessment theory. The presence of any predator
at the feeder lowered the number of visits to the feeder. Similarly, the tits were judged to have evaluated the sparrowhawk
as being more dangerous than the kestrel, as its presence lowered the number of arrivals more than did the kestrel. The duration
of stay and number of pecks of individual birds were also used as measures of predator dangerousness. The results not only
confirm that tits behave according to dynamic risk assessment theory, but also show the exceptional suitability of preference
experiments for the research of predator differentiation and evaluation. 相似文献
54.
Luděk Bartoš Jitka Bartošová Jan Pluháček Jana Šindelářová 《Behavioral ecology and sociobiology》2011,65(8):1567-1572
Based on questionnaires from horse breeders, we found that bringing a pregnant mare which had been mated away from home into
a vicinity of a familiar male who was not the father of her foetus increased probability of pregnancy disruption. These mares
aborted in 31% of cases, while none of those mated within the home stable aborted. Repeated sexual activity either by a stallion
or dominant gelding from the normal home group was observed shortly after the mare came from away-mating. Pregnant mares isolated
from home males by a fence were even seen soliciting them over the fence. We speculate that, once returned to the home “herd”,
and introduced to familiar males, mares were more likely to terminate their pregnancy to save energy and avoid likely future
infanticidal loss of their progeny by dominant male(s) of the home social group. This is a newly discovered phenomenon where
a mare manipulates the male’s paternity assessment by promiscuous mating. It may explain a common increased incidence of foetal
loss in domestic horses occurring in nearly 40% of pregnancies. We conclude that the common practice of transporting the mare
for mating and then bringing her back to an environment with males, stallions or geldings, which did not sire the foetus,
is the main cause of high percentages of pregnancy disruption in domestic horses. 相似文献
55.
Klára Řehounková Lukáš Čížek Jiří Řehounek Lenka Šebelíková Robert Tropek Kamila Lencová Petr Bogusch Pavel Marhoul Jan Máca 《Environmental science and pollution research international》2016,23(14):13745-13753
Open interior sands represent a highly threatened habitat in Europe. In recent times, their associated organisms have often found secondary refuges outside their natural habitats, mainly in sand pits. We investigated the effects of different restoration approaches, i.e. spontaneous succession without additional disturbances, spontaneous succession with additional disturbances caused by recreational activities, and forestry reclamation, on the diversity and conservation values of spiders, beetles, flies, bees and wasps, orthopterans and vascular plants in a large sand pit in the Czech Republic, Central Europe. Out of 406 species recorded in total, 112 were classified as open sand specialists and 71 as threatened. The sites restored through spontaneous succession with additional disturbances hosted the largest proportion of open sand specialists and threatened species. The forestry reclamations, in contrast, hosted few such species. The sites with spontaneous succession without disturbances represent a transition between these two approaches. While restoration through spontaneous succession favours biodiversity in contrast to forestry reclamation, additional disturbances are necessary to maintain early successional habitats essential for threatened species and open sand specialists. Therefore, recreational activities seem to be an economically efficient restoration tool that will also benefit biodiversity in sand pits. 相似文献
56.
Soudek P Petrová S Benešová D Dvořáková M Vaněk T 《Journal of environmental radioactivity》2011,102(6):598-604
Hydroponicaly cultivated plants were grown on medium containing uranium. The appropriate concentrations of uranium for the experiments were selected on the basis of a standard ecotoxicity test. The most sensitive plant species was determined to be Lactuca sativa with an EC50 value about 0.1 mM. Cucumis sativa represented the most resistant plant to uranium (EC50 = 0.71 mM). Therefore, we used the uranium in a concentration range from 0.1 to 1 mM.Twenty different plant species were tested in hydroponic solution supplemented by 0.1 mM or 0.5 mM uranium concentration. The uranium accumulation of these plants varied from 0.16 mg/g DW to 0.011 mg/g DW. The highest uranium uptake was determined for Zea mays and the lowest for Arabidopsis thaliana. The amount of accumulated uranium was strongly influenced by uranium concentration in the cultivation medium. Autoradiography showed that uranium is mainly localized in the root system of the plants tested. Additional experiments demonstrated the possibility of influencing the uranium uptake from the cultivation medium by amendments. Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba up to 2.8 times or 1.9 times, respectively. Phosphate deficiency increased uranium uptake up to 4.5 times or 3.9 times, respectively, by Brassica oleracea and S. alba. In the case of deficiency of iron or presence of cadmium ions we did not find any increase in uranium accumulation. 相似文献
57.
Radovan Kopp Miroslava Palíková Ondřej Adamovský Andrea Ziková Stanislav Navrátil Jiří Kohoutek Jan Mareš Luděk Bláha 《Environmental monitoring and assessment》2013,185(12):9717-9727
The aim of this study is to summarise the determination of concentrations of microcystins (MCs) in muscle and liver of freshwater fish species caught in stagnant waters of the Czech Republic. Within the years 2007–2009, 351 muscle samples and 291 liver samples of 16 freshwater fish species derived from four fishponds, and four water reservoirs were analysed. MCs were detected in 53 liver samples. The highest concentrations of microcystins were determined in liver samples of carnivorous fish species; 50.3 ng/g of fresh weight (FW) in perch (Perca fluviatilis) and 22.7 ng/g FW in pikeperch (Sander lucioperca). MCs in liver were detected in other five fish species; asp (Aspius aspius), pike (Esox lucius), common carp (Cyprinus carpio), grass carp (Ctenopharyngodon idella) and European eel (Anguilla anguilla). Concentrations of MCs in liver of nine fish species (European bream, whitefish, tench, silver carp, European catfish, roach, chub, crucian carp and rudd) were below the detection limit of 1.2–5.4 ng/g FW for different MC congeners. However, the concentrations of MCs in all muscle samples were below the detection limit. The assessment of MCs concentrations might be influenced by the detection method used. Due to the concentrations of MCs being below the detection limit in muscle samples of all fish species analysed, it seems that there might be a low potential threat for human health in case of fish muscle consumption. 相似文献
58.
António O. Soares Danny Haelewaters Olga M. C. C. Ameixa Isabel Borges Peter M. J. Brown Pedro Cardoso Michiel D. de Groot Edward W. Evans Audrey A. Grez Axel Hochkirch Milada Holecová Alois Honěk Ján Kulfan Ana I. Lillebø Zdenka Martinková J. P. Michaud Oldřich Nedvěd Omkar Helen E. Roy Swati Saxena Apoorva Shandilya Arnaud Sentis Jiri Skuhrovec Sandra Viglášová Peter Zach Tania Zaviezo John E. Losey 《Conservation biology》2023,37(1):e13965
Ladybirds (Coleoptera: Coccinellidae) provide services that are critical to food production, and they fulfill an ecological role as a food source for predators. The richness, abundance, and distribution of ladybirds, however, are compromised by many anthropogenic threats. Meanwhile, a lack of knowledge of the conservation status of most species and the factors driving their population dynamics hinders the development and implementation of conservation strategies for ladybirds. We conducted a review of the literature on the ecology, diversity, and conservation of ladybirds to identify their key ecological threats. Ladybird populations are most affected by climate factors, landscape composition, and biological invasions. We suggest mitigating actions for ladybird conservation and recovery. Short-term actions include citizen science programs and education, protective measures for habitat recovery and threatened species, prevention of the introduction of non-native species, and the maintenance and restoration of natural areas and landscape heterogeneity. Mid-term actions involve the analysis of data from monitoring programs and insect collections to disentangle the effect of different threats to ladybird populations, understand habitat use by taxa on which there is limited knowledge, and quantify temporal trends of abundance, diversity, and biomass along a management-intensity gradient. Long-term actions include the development of a worldwide monitoring program based on standardized sampling to fill data gaps, increase explanatory power, streamline analyses, and facilitate global collaborations. 相似文献
59.
The distribution of air-filled structures in the craniofacial and neurocranial bones of the oviraptorid ZPAL MgD-I/95, discovered
at the Hermiin Tsav locality, Mongolia, is restored. Based on the complete obliteration of most of the cranial sutures, the
specimen is identified as an adult individual of Conchoraptor gracilis Barsbold 1986. Except for the orbitosphenoids and epipterygoids, the preserved bones of the neurocranium are hollow. Three
types of tympanic recess are present in Conchoraptor, a characteristic shared with troodontids, dromaeosaurids, and avian theropods. The contralateral middle ear cavities are
interconnected by the supraencephalic pathway that passes through the dorsal tympanic recesses, the posterodorsal prootic
sinuses and the parietal sinus. The spatial arrangements of the middle ear cavity and a derived neurocranial pneumatic system
in Conchoraptor indicate enhancements of acoustic perception in the lower-frequency registers and of auditory directionality. We further
speculate that this improvement of binaural hearing could be explained as an adaptation required for accurate detection of
prey and/or predators under conditions of low illumination. The other potentially pneumatic structures of the Conchoraptor cranium include (1) recessus-like irregularities on the dorsal surface of the nasal and frontal bones (a putative oviraptorid
synapomorphy; pos); (2) a subotic recess; (3) a sub-condylar recess; and (4) a posterior condylar recess (pos).
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
60.
Dominance relationships among species play a major role in the structure of animal communities. Yet, dominant species with
different trade-offs in resource exploitation and monopolization could affect community structure in variable ways. In ants,
dominant species could be classified into either behavioral dominants that exhibit territorial aggression or numerical dominants
that exhibit high biomass or frequency of occurrence. While each class of dominance has generally been found to negatively
affect the foraging activity of species in ant communities, the concurrent effect of both classes of species has never been
tested. Here, we examined the effects of two behaviorally dominant species, Crematogaster inermis and Monomorium salomonis, and a numerically dominant species, Messor arenarius, on the foraging behavior of seed-eating species in a desert ant assemblage. In a 1-year study, the foraging activity of
the ant species was assessed using seed baits, which were sampled during night and day. While the numerically dominant species
exhibited high foraging efficiency and negatively affected the ability of other seed-eating species to obtain seeds, significantly
more seeds remained at baits that were occupied the previous night by each of the two behaviorally dominant species, possibly
due to aggressive exclusion of M. arenarius foragers from the baits. This exclusion also facilitated greater foraging activity of the seed-eating species. Our results
demonstrate how these two types of dominance could differently affect the foraging activity of ant species in the community. 相似文献