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Selvino R. de Kort Paula M. den Hartog Carel ten Cate 《Behavioral ecology and sociobiology》2002,51(4):378-385
Two closely related dove species, Streptopelia vinacea and S. capicola, show clear interspecific divergence in one acoustic signal (perch-coo), but much less so in another (bow-coo). Both signals
play a role in territorial defense and mate attraction and may thus convey information used for species recognition. In Uganda,
there is a small zone of overlap where the two species most probably hybridize. With playback experiments in allopatric populations
of each species we tested the potential of the two signal types for species isolation. Allopatric populations showed a stronger
response to conspecific than to heterospecific perch-coos, but an equal response to bow-coos of either species. However, S. vinacea responded relatively stronger to S. capicola perch-coos than vice versa. The hybrid population showed an equal response to bow-coos of either species, but a marginally
stronger response to perch-coos of S. capicola compared to perch-coos of S. vinacea. Hybrids have a variable and intermediate vocal structure compared to both parental species, which allowed for testing of
behavioral coupling between production and perception of these signals. Hybrids showed no relationship between their coo structure
and that of the species to which they respond most strongly, indicating a lack of behavioral coupling. Although perch-coos
may differ sufficiently to allow species isolation, the similarity in bow-coos may allow interspecific interactions. We suggest
that the similarity in bow-coos and the higher salience of S. capicola perch-coos may have allowed S. capicola to extend its range into that of S. vinacea, resulting in hybridization.
Electronic Publication 相似文献
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Environmental Flows (EFlows) are defined as the quantity, timing and quality of the flow of water, sediment and biota necessary to sustain freshwater and estuarine ecosystems, and the human livelihoods and well-being that depend on these ecosystems. As such they are a vital component of Integrated Water Resource Management (IWRM). A recent survey found that, in general, Africa lags behind schedule with respect to the global SDG Target 6.5 to implement IWRM at all levels, including through transboundary cooperation as appropriate. This web-based review explores progress made in EFlows Assessments and implementing their outcomes in southern Africa. It outlines the apparent impetus to the uptake of EFlows provided by legislation, common funding mechanisms for EFlows assessment and evolving trends in EFlows assessment. It also highlights instances of implementation of EFlows in both in-country and transboundary settings. 相似文献
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Mark Person Amlan Banerjee John Rupp Cristian Medina Peter Lichtner Carl Gable Rajesh Pawar Michael Celia Jennifer McIntosh Victor Bense 《International Journal of Greenhouse Gas Control》2010,4(5):840-854
Idealized, basin-scale sharp-interface models of CO2 injection were constructed for the Illinois basin. Porosity and permeability were decreased with depth within the Mount Simon Formation. Eau Claire confining unit porosity and permeability were kept fixed. We used 726 injection wells located near 42 power plants to deliver 80 million metric tons of CO2/year. After 100 years of continuous injection, deviatoric fluid pressures varied between 5.6 and 18 MPa across central and southern part of the Illinois basin. Maximum deviatoric pressure reached about 50% of lithostatic levels to the south. The pressure disturbance (>0.03 MPa) propagated 10–25 km away from the injection wells resulting in significant well–well pressure interference. These findings are consistent with single-phase analytical solutions of injection. The radial footprint of the CO2 plume at each well was only 0.5–2 km after 100 years of injection. Net lateral brine displacement was insignificant due to increasing radial distance from injection well and leakage across the Eau Claire confining unit. On geologic time scales CO2 would migrate northward at a rate of about 6 m/1000 years. Because of paleo-seismic events in this region (M5.5–M7.5), care should be taken to avoid high pore pressures in the southern Illinois basin. 相似文献
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The PC revolution continues to produce faster and smarter machines at a stunning pace. Almost forgotten in the rush are the millions of nearly new, but suddenly outdated, computers that are abandoned every year. Can product stewardship offer life‐after‐end‐of‐life for this growing mountain of “attic‐ware,” while averting a costly—and potentially toxic—waste disposal crisis? © 2001 by Cate Gable, Axioun Books. Used with permission. 相似文献
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Nicole Geberzahn Wolfgang Goymann Christina Muck Carel ten Cate 《Behavioral ecology and sociobiology》2009,64(2):193-204
Birdsong serves to attract mates and to deter territorial rivals. Even though song is not restricted to males, this dual function
has almost exclusively been demonstrated for male song. To test the generality of hypotheses on birdsong, we investigated
female song in the sex-role reversed, classically polyandrous African black coucal (Centropus grillii) in the context of female–female competition. We compared spontaneously vocalizing females with females vocally responding
to a playback simulating a conspecific intruder. Females changed vocal parameters in response to playbacks: They lowered the
pitch of their vocalizations and enhanced the duration of song elements when being challenged. Also, the composition of the
vocalizations was altered. There was no significant correlation between pitch and body size parameters in spontaneous song,
but there was for response songs, with larger females having a lower pitch. These changes in vocal properties suggest that
the vocalizations are important for mutual assessment of competitive abilities in females. Our findings confirm the general
role of intrasexual competition in vocal communication of birds. 相似文献