Ectoparasites and other invertebrates are known to play a role in bird behavior and in evolutionary adaptations such as preening and foraging strategies. We conducted an exploratory study by macro- and microscopically...Ectoparasites and other invertebrates are known to play a role in bird behavior and in evolutionary adaptations such as preening and foraging strategies. We conducted an exploratory study by macro- and microscopically evaluating the nests of Hair-crested Drongos(Dicrurus hottentottus) at Dongzhai National Nature Reserve, Henan Province, China in 2011 to determine if there was a presence of invertebrates. We developed a modified funneling technique to collect invertebrate samples and reduce contamination from outside sources in a field setting. We found several species of ectoparasites(lice and ticks) and other invertebrates(springtails and rove beetles) within the nests. Our findings warrant further investigation as to whether or not the presence of invertebrates in the nests of Hair-crested Drongos plays a role in the adaptation of the unique nest dismantling behavior exhibited by this species.展开更多
Jiuzhaigou, characterized by its magnificent waterscapes and subalpine karstic features, is both a World Heritage Site and a World Biosphere Reserve in southwestern China. In recent years, this unique ecosystem has sh...Jiuzhaigou, characterized by its magnificent waterscapes and subalpine karstic features, is both a World Heritage Site and a World Biosphere Reserve in southwestern China. In recent years, this unique ecosystem has shown signs of stress due to increasing tourism activities within the reserve. The various routine methods, which monitor physical and chemical properties, do not fully reflect water quality in the subalpine and alpine lakes, while the indicators using aquatic organisms to evaluate the water quality or status of the subalpine lakes are poorly reported. Thus, in this study, benthic diatoms from multiple habitats in Jiuzhaigou were sampled and assessed for water quality monitoring. Canonical Correspondence Analysis （CCA） showed that the canonical coefficients for elevation, water temperature and total nitrogen on the first Canonical Corresnondence Analysis axis were -0.84. 0.78 and -0.53, respectively, environmental variables associated with the distribution patterns of benthic diatoms. The dominance of diatom taxa indicative of nutrient enrichment indicates a clear trend toward eutrophication in the Pearl Shoal and Colorful Lake, two of the sites mostly visited by tourists. It was observed that the effect of the type of substratum on diatom community composition is not significant in subalpine lakes. The most dominant species in Jiuzhaigou lakes are the genera Achnanthes, Fragilaria, CymbeUa, Cocconeis, Diatoma and Denticula. In combination with dominant and sensitive species in the benthic diatom communities, CCA and CA methods can be used to evaluate the impact of human activities on subalpine karstic lakes. The dominance of diatom taxa is indicative of nutrient enrichment and the results of CCA and CA indicate a clear trend toward eutrophication in the Pearl Shoal and Colorful Lake, two of the sites mostly visited by tourists.展开更多
Radionuclide dating techniques characterized by137Cs and210Pbex have recently been applied in the study of lake sediments around the world.In this study,a chronological series of sediment cores was established based o...Radionuclide dating techniques characterized by137Cs and210Pbex have recently been applied in the study of lake sediments around the world.In this study,a chronological series of sediment cores was established based on137Cs and210Pbex analyses along with the evaluation of sediment properties,such as particle size distribution,total organic carbon(TOC),carbonate content,and acid-insoluble residue,to study sediment accumulation rates,sediment sources,and responses to human activities in the Jiuzhaigou National Nature Reserve in southwestern China.In terms of the particle size distribution of sediments,silt content was the highest,and clay and sand contents were relatively low.The sediments displayed high TOC contents because of the significant amounts of vegetation grown in the lakes.The carbonate content was also high due to the overall geological background of carbonates in Jiuzhaigou.Carbonate content tended to decline from top to bottom in the sediment cores,whereas the acid-insoluble residue tended to increase.These results suggested that the depth variation of the environmental parameters of the sediments in two lakes in Jiuzhaigou would correspond to each other.The results indicated that the sediment rate of Jiuzhaigou was generally high with strong siltation,indicating that serious soil loss was induced by intensive human activities in the basin over the past decades.The increases in the mass accumulation rate,contents of acid-insoluble residue,and mean particle size during the periods of 1840–1900s,late 1930s–early 1950s,1966–1978,and2003–2006 revealed the occurrence of severe soil and water loss as a result of extensive agricultural expansion,large-scale deforestation,and road construction in Jiuzhaigou.The deposition rate and the properties of lacustrine sediments could reflect the significant impact of human activities on lake sedimentation during Jiuzhaigou′s history.展开更多
基金support by Dongzhai National Nature Reserve for conducting this studyprovided by National Science Foundation East Asia Pacific Summer Institute(EAPSI)+1 种基金Chinese Ministry of Science and Technology,and China Science and Technology Exchange Centerprovided by Alabama A&M University and Beijing Normal University
文摘Ectoparasites and other invertebrates are known to play a role in bird behavior and in evolutionary adaptations such as preening and foraging strategies. We conducted an exploratory study by macro- and microscopically evaluating the nests of Hair-crested Drongos(Dicrurus hottentottus) at Dongzhai National Nature Reserve, Henan Province, China in 2011 to determine if there was a presence of invertebrates. We developed a modified funneling technique to collect invertebrate samples and reduce contamination from outside sources in a field setting. We found several species of ectoparasites(lice and ticks) and other invertebrates(springtails and rove beetles) within the nests. Our findings warrant further investigation as to whether or not the presence of invertebrates in the nests of Hair-crested Drongos plays a role in the adaptation of the unique nest dismantling behavior exhibited by this species.
基金funded by the Programme of Introducing Talents of Discipline to Universities(the 111 Project)(grant no.B08037)National Key Technology R&D Program of China(grant no.2012BAC06B02)
文摘Jiuzhaigou, characterized by its magnificent waterscapes and subalpine karstic features, is both a World Heritage Site and a World Biosphere Reserve in southwestern China. In recent years, this unique ecosystem has shown signs of stress due to increasing tourism activities within the reserve. The various routine methods, which monitor physical and chemical properties, do not fully reflect water quality in the subalpine and alpine lakes, while the indicators using aquatic organisms to evaluate the water quality or status of the subalpine lakes are poorly reported. Thus, in this study, benthic diatoms from multiple habitats in Jiuzhaigou were sampled and assessed for water quality monitoring. Canonical Correspondence Analysis （CCA） showed that the canonical coefficients for elevation, water temperature and total nitrogen on the first Canonical Corresnondence Analysis axis were -0.84. 0.78 and -0.53, respectively, environmental variables associated with the distribution patterns of benthic diatoms. The dominance of diatom taxa indicative of nutrient enrichment indicates a clear trend toward eutrophication in the Pearl Shoal and Colorful Lake, two of the sites mostly visited by tourists. It was observed that the effect of the type of substratum on diatom community composition is not significant in subalpine lakes. The most dominant species in Jiuzhaigou lakes are the genera Achnanthes, Fragilaria, CymbeUa, Cocconeis, Diatoma and Denticula. In combination with dominant and sensitive species in the benthic diatom communities, CCA and CA methods can be used to evaluate the impact of human activities on subalpine karstic lakes. The dominance of diatom taxa is indicative of nutrient enrichment and the results of CCA and CA indicate a clear trend toward eutrophication in the Pearl Shoal and Colorful Lake, two of the sites mostly visited by tourists.
基金Under the auspices of Programme of Introducing Talents of Discipline to Universities(the 111 Project)(No.B08037)National Key Technology R&D Program of China(No.2012BAC06B02)
文摘Radionuclide dating techniques characterized by137Cs and210Pbex have recently been applied in the study of lake sediments around the world.In this study,a chronological series of sediment cores was established based on137Cs and210Pbex analyses along with the evaluation of sediment properties,such as particle size distribution,total organic carbon(TOC),carbonate content,and acid-insoluble residue,to study sediment accumulation rates,sediment sources,and responses to human activities in the Jiuzhaigou National Nature Reserve in southwestern China.In terms of the particle size distribution of sediments,silt content was the highest,and clay and sand contents were relatively low.The sediments displayed high TOC contents because of the significant amounts of vegetation grown in the lakes.The carbonate content was also high due to the overall geological background of carbonates in Jiuzhaigou.Carbonate content tended to decline from top to bottom in the sediment cores,whereas the acid-insoluble residue tended to increase.These results suggested that the depth variation of the environmental parameters of the sediments in two lakes in Jiuzhaigou would correspond to each other.The results indicated that the sediment rate of Jiuzhaigou was generally high with strong siltation,indicating that serious soil loss was induced by intensive human activities in the basin over the past decades.The increases in the mass accumulation rate,contents of acid-insoluble residue,and mean particle size during the periods of 1840–1900s,late 1930s–early 1950s,1966–1978,and2003–2006 revealed the occurrence of severe soil and water loss as a result of extensive agricultural expansion,large-scale deforestation,and road construction in Jiuzhaigou.The deposition rate and the properties of lacustrine sediments could reflect the significant impact of human activities on lake sedimentation during Jiuzhaigou′s history.
