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811.
812.
Harvey D. Blankespoor Stephen C. Cameron John Cairns Jr. 《Environmental management》1985,9(5):455-458
Two species of pulmonate snails,Lymnaea cat-ascopium andPhysa integra, were collected from Douglas and Houghton Lakes. Snail populations from the former lake (pristine) had never been exposed to copper sulfate, whereas those from the latter one (treated) had been subjected to the molluscicide for more than 40 years. Molluscs from the treated lake were more resistant to the copper at concentrations of 0.5 and 1.0 ppm than those from the pristine lake. Furthermore, larger lymnaeids had a higher survival rate than smaller ones. 相似文献
813.
814.
Stephen P. Leatherman 《Environmental management》1989,13(1):109-115
A study of historical storm-induced changes along the south shore barriers of Long Island (Fire Island Inlet to Southampton), New York, USA, was undertaken in an effort to determine the relative roles of different transport processes in barrier migration. Inlets were found to have a profound effect on the barrier system, largely controlling its landward migration, based upon maps, charts, and aerial photographs from the seventeenth century to the present. Salt marshes became established principally on the broad intertidal bay shoals left by a closed or slowly migrating inlet. Inlets along this microtidal coast are now stabilized by jetties, which may have a negative effect on long-term barrier-island migration. 相似文献
815.
816.
Stuart A. Altmann Stephen S. Wagner Sarah Lenington 《Behavioral ecology and sociobiology》1977,2(4):397-410
Summary Two models of conditions for the evolution of polygyny are treated axiomatically. Both models assume a social system based on female mate choice in situations in which a female is better off if she mates polygynously with an already mated male on a superior territory than if she selects a bachelor on an inferior territory. One model, the competitive female choice model, assumes that the females of a harem compete for the limited resources of the harem and thus that their fitness decreases as co-wives are added. The cooperative female choice model assumes that, within limits, a female's fitness is improved by the addition of co-wives to her mate's harem, as a result of cooperative interactions within the group. For each model, a sufficient set of independent assumptions is provided. Implications of the models are indicated and methods for testing them are discussed. 相似文献
817.
Regulations at recreation sites have been described as anathema to recreation itself. Many recent authors have suggested that managers use more light-handed techniques, such as information and education, before attempting regulatory and intrusive actions. This study of visitors to Glacier National Park in Montana, USA, during the fall bald eagle migration season demonstrates that, under certain conditions, recreationists will view regulations as a way to enhance the opportunity rather than detract from it. The results reinforce previous suggestions in the literature that managers carefully examine the objectives and consequences of regulations prior to their use. 相似文献
818.
Nicola Weber Stuart Bearhop Sasha R. X. Dall Richard J. Delahay Robbie A. McDonald Stephen P. Carter 《Behavioral ecology and sociobiology》2013,67(3):471-479
Heterogeneities in behaviours of individuals may underpin important processes in evolutionary biology and ecology, including the spread of disease. Modelling approaches can sometimes fail to predict disease spread, which may partly be due to the number of unknown sources of variation in host behaviour. The European badger is a wildlife reservoir for bovine tuberculosis (bTB) in Britain and Ireland, and individual behaviour has been demonstrated to be an important factor in the spread of bTB among badgers and to cattle. Radio-telemetry devices were deployed on 40 badgers from eight groups to investigate patterns of den (sett) use in a high-density population, where each group had one or two main and three to eight outlier setts in their territory. Badgers were located at their setts for 28 days per season for 1 year to investigate how patterns differed between individuals. Denning behaviour may have a strong influence on contact patterns and the transmission of disease. We found significant heterogeneity, influenced by season, sex and age. Also, when controlling for these, bTB infection status interacting with season was highly correlated with sett use. Test-positive badgers spent more time away from their main sett than those that tested negative. We speculate that wider-ranging behaviour of test-positive animals may result in them contacting sources of infection more frequently and/or that their behaviour may be influenced by their disease status. Measures to control infectious diseases might be improved by targeting functional groups, specific areas or times of year that may contribute disproportionately to disease spread. 相似文献
819.
Scent-marking is a frequent behaviour of highly social ground squirrels and might play an important role in their social dynamics.
Female Columbian ground squirrels exhibit considerable scent-marking during the reproductive period. We examined how gestating
and lactating females responded to jugal gland scent-marks of same-sexed and opposite-sexed conspecifics with attention to
genetic relatedness and the geographical location of the territory of individuals. We tested the dear-enemy, threat-level
and kin-discrimination hypotheses to explain patterns of scent-marking. Females sniffed the scent of non-neighbouring males
significantly longer than other types of scent categories and tended to over mark the scent of females more than the scent
of males. Furthermore, females sniffed significantly longer at scents during gestation than during lactation. We concluded
that scent-marking mainly functioned in the defence of female territories and for protection of pups against infanticidal
females (threat-level hypothesis). Our results were also in accordance with the kin-discrimination hypothesis, because greater
attention was paid to the marks of non-kin females. Kin females might not pose an infanticidal threat, perhaps explaining
greater tolerance among related reproductive females. We concluded that scent-marking may be a relatively low-cost means of
territorial defence, as well as a means of communication of aspects of individual identity. 相似文献
820.
William A. Searcy Susan Peters Silke Kipper Stephen Nowicki 《Behavioral ecology and sociobiology》2010,64(8):1343-1349
One explanation for why female songbirds attend to male song is that the quality of a male's song is associated with the quality
of his developmental history. We tested this hypothesis by playing back to female swamp sparrows (Melospiza georgiana) songs recorded from males of either inferior or superior developmental histories, as assessed by their rates of mass gain
during the first 18 days post-hatching. Females showed significantly higher levels of courtship display in response to songs
of males with superior growth than to songs of males with inferior growth. Out of nine song traits measured, only song duration
correlated with variation in female response; duration was also the only trait that differed significantly in univariate comparisons
between the superior growth songs and the inferior growth songs. In a multivariate analysis, however, inferior growth songs
were best discriminated from superior growth songs by combining three song traits: trill rate, stereotypy, and the number
of notes per syllable. We suggest that early developmental stress degrades song in many small ways, and that it is the cumulative
effect of the resulting deficits that explains lower female response. 相似文献