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31.
Many mammals warn conspecifics with alarm calls about detected predators. These alarm calls are either functionally referential,
urgency based, or they can have multiple functions, including predator deterrence. The taxonomic distribution of these alarm
call systems is uneven, with primates providing the best-known examples for a functionally referential system and rodents
most examples of an urgency-based system. Reports of different alarm call systems in lemurid primates prompted us to examine
the anti-predator behavior of two additional lemur species. In an experimental field study we exposed adult redfronted lemurs
(Eulemur fulvus rufus) and white sifakas (Propithecus verreauxi verreauxi) to playbacks of vocalizations of their main aerial and terrestrial predators, as well as to their own alarm calls given
in response to the presentation of these predators. We scored the subjects' immediate behavioral responses, including alarm
calls, from video recordings made during the first minute following a playback. We found that both species gave specific alarm
calls only in response to raptor playbacks and the corresponding alarm calls, whereas calls given in response to carnivores
and the corresponding alarm calls were also observed in other situations characterized by high arousal. Other behavioral responses,
such as gaze and escape directions, corresponded to the hunting strategies of the two predator classes, suggesting that the
corresponding vocalizations were categorized correctly. These two lemur species, which represent different families, have
therefore independently evolved a mixed alarm call system, characterized by functionally referential calls for diurnal raptors,
but not for carnivores. Electronic supplementary material to this paper can be obtained by using the Springer LINK server
located at http://dx.doi.org/10.1007/s00265-001-0436-0
Electronic Publication 相似文献
32.
András Bardossy Arne Färber Steffen Schönau Bernhard Westrich Thomas Jancke Gerhard Schmid Sven Wurms Karl Stahr Thomas Gaiser Harald Frauenknecht Thilo Streck Joachim Ingwersen Claudia Kreschnak Ulrich Kern Hilke Heppelmann Ekkehard Christoffels Ulrich Förstner Patrick Jacobs 《Environmental Sciences Europe》2006,18(1):67-69
33.
Tina?NilssonEmail author Claudia?Fricke G?ran?Arnqvist 《Behavioral ecology and sociobiology》2003,53(4):227-233
The number of eggs fertilized by a male at any given copulation (fertilization success) is affected by a large number of factors. Male insemination and sperm competition success and various female structures and/or processes that bias paternity in favor of some males over others (cryptic female choice) are all likely to affect fertilization success. We suggest that more comprehensive measures of male fertilization success can increase our understanding of postcopulatory sexual selection. To improve our understanding of the importance of various sources of variance in male fertilization success, we conducted a series of experiments using flour beetles. Different wild-type strains were used in reciprocal double mating experiments, against a phenotypic marker strain. We assessed the relative effects of female genotype, male genotype and mating order on independent and inclusive measures of male defense ability ( P 1), male offense ability ( P 2), and female remating behavior. Female genotype influenced both P 1 and P 2, and male genotype interacted strongly with female genotype in its effect on P 2. We also documented an interaction between female and male genotypes in the effects of mating on female remating behavior, such that females tended to remate most rapidly when mated to males of their own genotype. It is clear from our experiments that cryptic female choice influences the pattern of fertilization success in flour beetles, and we suggest that cryptic female choice may often be an important component of postcopulatory sexual selection. Future investigations would benefit from studying the multiple components of variance in male fertilization success. 相似文献
34.
Average longevity in free-living edible dormice (Glis glis) can reach 9 years, which is extremely high for a small rodent. This remarkable life span has been related to a peculiar
life history strategy and the rarity of reproductive bouts in these seed eaters. Most females (96%) reproduce only once or
twice in their lifetime, predominantly during years of mast seeding of, e.g., beech, but entire populations can skip reproduction
in years of low seed availability. Surprisingly, in non-reproductive years, large fractions of populations apparently vanished
and were never captured above ground. Therefore, we determined the duration of above-ground activity, and body temperature
profiles in a subset of animals, of dormice under semi-natural conditions in outdoor enclosures. We found that non-reproductive
dormice returned to dormancy in underground burrows throughout summer after active seasons as short as <2 weeks. Thus, animals
spent up to >10 months per year in dormancy. This exceeds dormancy duration of any other mammal under natural conditions.
Summer dormancy was not caused by energy constraints, as it occurred in animals in good condition, fed ad libitum and without
climatic stress. We suggest that almost year-round torpor has evolved as a strategy to escape birds of prey, the major predators
of this arboreal mammal. This unique predator-avoidance strategy clearly helps in explaining the unusually high longevity
of dormice. 相似文献
35.
Annette Piorr Fabrizio Ungaro Arianna Ciancaglini Kathrin Happe Amanda Sahrbacher Claudia Sattler Sandra Uthes Peter Zander 《Environmental Science & Policy》2009,12(8):1122-1136
The recent and upcoming reforms of the Common Agricultural Policies (CAPs) aim at strengthening the multifunctional role of agriculture, acknowledging the differences in economic, environmental and social potentials within European regions. This paper presents results from an integrated assessment of existing and future policies within the framework set up in the FP6 EU project MEA-Scope. Spatial explicit procedures allow for the MEA-Scope modelling tools to provide information related to regional, environmental and socio-economics settings. The impact of different policy scenarios on structural change, land abandonment and cropping pattern of typical farms has been assessed based on linked agent-based (ABM) and Linear Programming (LP) models at regional and farm scale for two study areas. For the German case study area Ostprignitz-Ruppin (OPR), the issue of policy targeting has been addressed by relating non-commodity outputs (NCOs) to soil quality and protection status. For the Italian case study area (Mugello), changes in landscape patterns in terms of increased fragmentation or homogeneity as affected by changes in agricultural intensity have been analysed using semivariance analysis. The spatial explicit approach highlighted the relevance of case study research in order to identifying response structures and explaining policy implementation patterns. 相似文献
36.
Monika Suškevičs Thomas Hahn Romina Rodela Biljana Macura Claudia Pahl-Wostl 《Journal of Environmental Planning and Management》2018,61(7):1085-1112
Learning is considered as a promising mechanism to cope with rapid environmental change. The implications of learning for natural resource management (NRM) have not been explored in-depth and the evidence on the topic is scattered across multiple sources. We provide a qualitative review of types of learning outcomes and consider their manifestations in NRM across selected empirical literature. We conducted a systematic search of the peer-reviewed literature (N = 1,223) and a qualitative meta-synthesis of included articles, with an explicit focus on learning outcomes and NRM changes (N = 53). Besides social learning, we found several learning concepts used, including policy and transformative learning, and multiple links between learning and NRM reported. We observe that the development of skills, together with a system approach involving multi-level capacities, is decisive for implications of learning for NRM. Future reviews could systematically compare how primary research applies different learning concepts and discusses links between learning and NRM changes. 相似文献
37.
To examine the suitability of benthic foraminifera and their test deformations as bioindicators of pollution in coastal marine environments, we studied foraminifera and metal concentrations in 72 marine sediment samples, collected from the inner shelf along the Sicilian coast (Gulfs of Palermo and Termini) and on the south-eastern coast of Lampedusa Island. These areas are characterised by different environmental conditions. On the basis of pollution sources and foraminiferal assemblages, we recognised different zones in the Gulf of Palermo. The most polluted zones showed high metal concentrations, and low diversity of benthic foraminifera with species typical of stressed environments. By contrast, the lowest polluted zones showed a high population density and the highest percentages of epiphytes. Epiphytes were abundant where a Posidonia oceanica meadow was present and decreased in the most polluted zones. Sediments of the Gulf of Termini and Lampedusa exhibited high percentages of benthic foraminifera typical of well-oxygenated waters and low concentrations of metals, with the exception of sites located near sewage outfalls and harbour areas. Furthermore, even though deformed tests are commonly known in natural stressed environmental conditions, this study shows that in the most polluted zones, benthic foraminifera were characterised by the highest percentages of deformed individuals. 相似文献
38.
The allelopathic potential of fescue (Festuca arundinacea Shreb.) was investigated under field and laboratory conditions. In the field, incorporation of fescue aboveground biomass
into the soil provided an effective weed control as it significantly reduced both the number and the dry weight of all weed
species. The effect on weeds was species specific. The reduction of the most abundant species, Picris echioides, with respect to the number of individuals and their dry weight was 67 and 45%. Fescue aboveground biomass, harvested immediately
before soil incorporation, was utilized in a bioassay-oriented fractionation, aimed at identifying the compounds in the toxic
extracts of the plant. While phytotoxic activity was detected for the n-butanol fraction, no activity was found for the aqueous one. Germination of an indicator species, lettuce (Lactuca sativa L.), was reduced by 33% at the higher extract concentration of 20 mg/mL, owing to the increase of the number of abnormal
seedlings. The LC/MS profile of the extract revealed the presence of two alkaloids, seven flavonol glycosides, and two flavonol
aglyca. Quercetin 3-O-rutinoside, isorhamnetin 3-O-rutinoside, and kaempferol 3-O-rutinoside were reported in fescue for the first time. 相似文献
39.
Bruno G. Lages Beatriz G. Fleury Ana M. C. Hovell Claudia M. Rezende Angelo C. Pinto Joel C. Creed 《Marine Biology》2012,159(7):1551-1559
Competition for space changes species’ distributions and community organization on tropical rocky shores, and the presence of secondary metabolites in the tissues of non-indigenous species may aid them in establishing and expanding their range through negative competitive interactions. The aim of this study was to describe the range of chemical substances produced by the non-indigenous cup corals Tubastraea coccinea and T. tagusensis and to test whether they varied in the field when the corals were placed in proximity to two local competitors. Cholest-5-en-3β-ol and 9-octadecanoic acid were two common secondary metabolites found in the tissues of Tubastraea. In the competition interaction experiment, necrosis was detected on the tissues of the coral Mussismilia hispida, and this species induced variation in sterol, alkaloid, and fatty acid production in Tubastraea tissues. In contrast, a sponge overgrew Tubastraea colonies. These results indicate that chemical defense may contribute to the ability of these non-indigenous corals to invade native communities. 相似文献
40.
Giuseppe Esposito Riccardo Salvini Fabio Matano Marco Sacchi Claudia Troise 《Journal of Coastal Conservation》2018,22(5):957-972
Geomorphic evolution of sea cliffs has significant impact on coastal settlements worldwide, so that evaluation of cliff instability processes, failure factors, and retreat rates involves a growing number of scientists for coastal risk and management purposes. Aerial photogrammetry and lidar are among the most used techniques for topographic characterization and geomorphic monitoring of coastal environments. A crucial role in the combined use of such techniques is the evaluation of different spatial accuracy and co-registration between derived terrain models, so that a robust error analysis is required. In this study, we present a change detection analysis of the Torrefumo coastal cliff, in the Campi Flegrei volcanic area (Southern Italy). Aerial images taken in 1956 and 1974, processed through digital photogrammetry, and an airborne lidar point cloud acquired in 2008 were used to produce Digital Elevation Models of the cliff. The analysis was based on the multi-temporal comparison of these models and included the calculation of volumetric changes and average retreat rates of the cliff face with reference to the 1956–1974 and 1974–2008 time intervals. The spatially variable elevation uncertainty of each Digital Elevation Model was evaluated with a probabilistic approach based on the fuzzy set theory. The results of this study showed significant eroded volumes during the period 1956–1974 and relatively smaller volumes in the 1974–2008 time span, with mean annual retreat rates of 1.2 m/year and 0.17 m/year, respectively. We infer that the significant decrease of erosion characterizing the second period was induced by the sheltering effect at the base of the cliff produced by the construction of a seawall in the early 80’s. 相似文献