Ecological niche modeling has emerged as an useful tool in the investigation of the phylogeographic histories of species or communities in a region. The high biodiversity （oftentimes cryptic）, and complex geography ...Ecological niche modeling has emerged as an useful tool in the investigation of the phylogeographic histories of species or communities in a region. The high biodiversity （oftentimes cryptic）, and complex geography and geological history of Southeast Asia particularly call for multipronged approaches in phylogeographic investigations. Past studies have focused on taxa that are associated with lowland rainforests, which is the dominant natural vegetation type. Here, we combine published phylogenetic data, ecological niche modeling and paleo-climate models to reveal potential drivers of divergence in two open-forest bird species, the oriental magpie-robin Copsychus saularis and Coppersmith barbet Megalaima haemacephala. In spite of broad overlap in current distributions, there are subtle differences in their climatic niches, which result in different responses to past climatic changes. For C saularis, both Last Glacial Maximum climate models indicated that the entire Sundaland was climati- cally suitable, while phylogenetic analyses found divergent eastern and western Sundaland lineages. We thus postulate that this genetic divergence was a result of past separations of coastal habitats into eastern and western portions due to the emergence of Sunda shelf as sea-level fell. The current separation of morphological subspecies in Borneo is maintained by low climatic suitability （high annual rainfall） in certain regions. The extirpation of M. haemacephala from Borneo and southern Malay Peninsula might have been driven by unsuitable conditions （high temperature seasonality） in central Sundaland and/or the lack of open woodlands. Our study shows that ecological niche modeling adds a powerful dimension to our attempt to understand lineage evolution in space [Current Zoology 61 （5）： 922-934, 2015].展开更多
Song plays a fundamental role in intraspecific communication in songbirds.The temporal and structural components of songs can vary in different habitats.These include urban habitats where anthropogenic sounds and alte...Song plays a fundamental role in intraspecific communication in songbirds.The temporal and structural components of songs can vary in different habitats.These include urban habitats where anthropogenic sounds and alteration of habitat structure can significantly affect songbird vocal behavior.Urban-rural variations in song complexity,song length and syllable rate are not fully understood.In this study,using the oriental magpie-robin(Copsychus saularis)as a model,we investigated urban-rural variation in song complexity,song length,syllable rate,syllable length and inter-syllable interval.Comparing urban and rural songs from 7 countries across its natural Asiatic range(Bangladesh,India,Malaysia,Nepal,Singapore,Sri Lanka and Thailand),we found no significant differences in oriental magpie-robin song complexity.However,we found significant differences in temporal song variables between urban and rural sites.Longer songs and inter-syllable intervals in addition to slower syllable rates within urban sites contributed the most to this variance.This indicates that the urban environment may have driven production of longer and slower songs to maximize efficient transmission of important song information in urban habitats.展开更多
文摘Ecological niche modeling has emerged as an useful tool in the investigation of the phylogeographic histories of species or communities in a region. The high biodiversity （oftentimes cryptic）, and complex geography and geological history of Southeast Asia particularly call for multipronged approaches in phylogeographic investigations. Past studies have focused on taxa that are associated with lowland rainforests, which is the dominant natural vegetation type. Here, we combine published phylogenetic data, ecological niche modeling and paleo-climate models to reveal potential drivers of divergence in two open-forest bird species, the oriental magpie-robin Copsychus saularis and Coppersmith barbet Megalaima haemacephala. In spite of broad overlap in current distributions, there are subtle differences in their climatic niches, which result in different responses to past climatic changes. For C saularis, both Last Glacial Maximum climate models indicated that the entire Sundaland was climati- cally suitable, while phylogenetic analyses found divergent eastern and western Sundaland lineages. We thus postulate that this genetic divergence was a result of past separations of coastal habitats into eastern and western portions due to the emergence of Sunda shelf as sea-level fell. The current separation of morphological subspecies in Borneo is maintained by low climatic suitability （high annual rainfall） in certain regions. The extirpation of M. haemacephala from Borneo and southern Malay Peninsula might have been driven by unsuitable conditions （high temperature seasonality） in central Sundaland and/or the lack of open woodlands. Our study shows that ecological niche modeling adds a powerful dimension to our attempt to understand lineage evolution in space [Current Zoology 61 （5）： 922-934, 2015].
文摘Song plays a fundamental role in intraspecific communication in songbirds.The temporal and structural components of songs can vary in different habitats.These include urban habitats where anthropogenic sounds and alteration of habitat structure can significantly affect songbird vocal behavior.Urban-rural variations in song complexity,song length and syllable rate are not fully understood.In this study,using the oriental magpie-robin(Copsychus saularis)as a model,we investigated urban-rural variation in song complexity,song length,syllable rate,syllable length and inter-syllable interval.Comparing urban and rural songs from 7 countries across its natural Asiatic range(Bangladesh,India,Malaysia,Nepal,Singapore,Sri Lanka and Thailand),we found no significant differences in oriental magpie-robin song complexity.However,we found significant differences in temporal song variables between urban and rural sites.Longer songs and inter-syllable intervals in addition to slower syllable rates within urban sites contributed the most to this variance.This indicates that the urban environment may have driven production of longer and slower songs to maximize efficient transmission of important song information in urban habitats.
