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Werner Loher 《Behavioral ecology and sociobiology》1979,5(3):253-262
Summary Locomotor activity of the Teleogryllus commodus is under circadian control, with LL=25.3 h and DD=23.4 h. In LD 12:12 h, running occurs either exclusively during darkness (57%), mainly in the dark phase (35%), or with substantial activity peaks in both phases (8%). For oviposition, LL>24 h and DD<24 h; in LD 12:12 h, 80% of the studied deposited their eggs mainly during the light phase and 20% primarily during darkness. In the discussion, a temporal correlation between stridulation, spermatophore formation, and locomotion, and oviposition is established, which serves to make an encounter and mating between the sexes as likely as possible.Dedicated to Prof. Dr. M. Gersch on the occasion of his 70th birthday 相似文献
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Werner Kuhn 《Die Naturwissenschaften》1963,50(6):171-177
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Werner von Bloh Christine Bounama Klaus EisenackBrigitte Knopf Oliver Walkenhorst 《Ecological modelling》2008
To determine the influence of the biosphere on weathering we use a dynamic model of the global carbon cycle. It takes into account the most important processes for the long-term evolution of the Earth. The model is solved under a slowly changing environment of increasing solar luminosity and volcanic activity and continental area. By comparing the model results for the global average temperature with data derived from δ18O values from cherts it is possible to quantify the biogenic enhancement factor of weathering. For this purpose a newly developed inverse viability method is applied, which allows for calculating the range of possible biogenic enhancement factors consistent with the data. We find that in the Precambrian the weathering was 5.4 times lower than in the Phanerozoic era. This supports the hypothesis that the Cambrian explosion was caused by a positive feedback between the spread of biosphere, increased silicate weathering, and a consequent cooling of the climate. 相似文献
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Null model analysis of species nestedness patterns 总被引:6,自引:0,他引:6
Nestedness is a common biogeographic pattern in which small communities form proper subsets of large communities. However, the detection of nestedness in binary presence-absence matrices will be affected by both the metric used to quantify nestedness and the reference null distribution. In this study, we assessed the statistical performance of eight nestedness metrics and six null model algorithms. The metrics and algorithms were tested against a benchmark set of 200 random matrices and 200 nested matrices that were created by passive sampling. Many algorithms that have been used in nestedness studies are vulnerable to type I errors (falsely rejecting a true null hypothesis). The best-performing algorithm maintains fixed row and fixed column totals, but it is conservative and may not always detect nestedness when it is present. Among the eight indices, the popular matrix temperature metric did not have good statistical properties. Instead, the Brualdi and Sanderson discrepancy index and Cutler's index of unexpected presences performed best. When used with the fixed-fixed algorithm, these indices provide a conservative test for nestedness. Although previous studies have revealed a high frequency of nestedness, a reanalysis of 288 empirical matrices suggests that the true frequency of nested matrices is between 10% and 40%. 相似文献
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Laura Bouriaud Mariella Marzano Manfred Lexer Liviu Nichiforel Christopher Reyer Christian Temperli Heli Peltola Ché Elkin Gabriel Duduman Philip Taylor Stephen Bathgate Jose G. Borges Sandra Clerkx Jordi Garcia-Gonzalo Carlos Gracia Geerten Hengeveld Seppo Kellomäki Georgi Kostov Michael Maroschek Bart Muys Gert-Jan Nabuurs Bruce Nicoll Marc Palahí Werner Rammer Duncan Ray Mart-Jan Schelhaas Louise Sing Margarida Tomé Juergen Zell Marc Hanewinkel 《Regional Environmental Change》2015,15(8):1595-1609