Background: Edge effects cause changes in bird community richness, abundance, and/or distribution within a landscape, but the avian guilds most influenced can vary among regions. Although Southeast Asia has the highes...Background: Edge effects cause changes in bird community richness, abundance, and/or distribution within a landscape, but the avian guilds most influenced can vary among regions. Although Southeast Asia has the highest rates of deforestation and projected species loss, and is currently undergoing an explosive growth in road infrastructure, there have been few studies of the effects of forest edges on avian communities in this region.Methods: We examined avian community structure in a dry evergreen forest in northeastern Thailand adjacent to a five-lane highway. We evaluated the richness and abundance of birds in 11 guilds at 24 survey points on three parallel transects perpendicular to the edge. At each point, 10-min surveys were conducted during February-August 2014 and March-August 2015. Vegetation measurements were conducted at 16 of the bird survey points and ambient noise was measured at all 24 survey points.Results: We found a strongly negative response to the forest edge for bark-gleaning, sallying, terrestrial, and understory insectivores and a weakly negative response for arboreal frugivore-insectivores, foliage gleaning insectivores, and raptors. Densities of trees and the percentage canopy cover were higher in the interior, and the ambient noise was lower. In contrast, arboreal nectarivore-insectivores responded positively to the forest edge, where there was a higher vegetation cover in the ground layer, a lower tree density, and a higher level of ambient noise.Conclusion: Planners should avoid road development in forests of high conservation value to reduce impacts on biodiversity. Where avoidance is impossible, a number of potential mitigation methods are available, but more detailed assessments of these are needed before they are applied in this region.展开更多
Overall abundance and species composition of radiolarian faunas were analyzed in surface sediment samples from representative areas of South China Sea, East China Sea, Sea of Japan, Sea of Okhotsk, Bering Sea, Philipp...Overall abundance and species composition of radiolarian faunas were analyzed in surface sediment samples from representative areas of South China Sea, East China Sea, Sea of Japan, Sea of Okhotsk, Bering Sea, Philippine Sea, and the western boundary current regions of the North Pacific, in order to understand the biogeographic distribution ofradiolarians in the Northwest Pacific and explore its relationship with the main environmental factors and the North Pacific circulation. The results showed that radiolarians in the Northwest Pacific surface sediments can be divided into two large biogeographic provinces---cluster A and cluster B. Cluster A is characterized by the dominance of warm-water species and distributed primarily in tropical and subtropical seas with high radiolarian abundance and diversity; whereas cluster B is predominated by cold water species and distributed mainly in the Arctic and subarctic seas with comparably low abundance and diversity. Cluster A is further divided into five subclusters, AI to A5, which correspond to East China Sea, Philippine Sea, South China Sea, Sea of Japan, and Kuroshio Current, respectively; cluster B is divided into three subclusters, B1 to B3, which correspond to Sea of Okhotsk, Bering Sea, and subarctic gyre area, respectively. Based on the relationships between radiolarian faunas and major environment parameters in different biogeographic provinces, we suggest that the sea surface temperature （SST） and sea surface salinity （SSS） are primary factors that influence productivity, composition, and distribution pattern of the radiolarian fauna in the Northwest Pacific regions, while water depth is likely responsible for regional differences in the radiolarian fauna in each marginal sea. In addition, according to the distribution and abundance patterns of common radiolarian species in different areas, we identified five special radiolarian assemblages, which may be used as indicators for main Kuroshio Current, Kuroshio-East China Sea Branch, Kuroshio-South China Sea Branch, Tsushima Current, and Oyashio Current water masses.展开更多
基金supported by King Mongkut’s University of Technology Thonburi(Thailand)the National Science and Technology Development Agency(CPMO P-14-51347)supported by the Royal Golden Jubilee Ph.D.Program,Thailand(PHD/0036/2556)
文摘Background: Edge effects cause changes in bird community richness, abundance, and/or distribution within a landscape, but the avian guilds most influenced can vary among regions. Although Southeast Asia has the highest rates of deforestation and projected species loss, and is currently undergoing an explosive growth in road infrastructure, there have been few studies of the effects of forest edges on avian communities in this region.Methods: We examined avian community structure in a dry evergreen forest in northeastern Thailand adjacent to a five-lane highway. We evaluated the richness and abundance of birds in 11 guilds at 24 survey points on three parallel transects perpendicular to the edge. At each point, 10-min surveys were conducted during February-August 2014 and March-August 2015. Vegetation measurements were conducted at 16 of the bird survey points and ambient noise was measured at all 24 survey points.Results: We found a strongly negative response to the forest edge for bark-gleaning, sallying, terrestrial, and understory insectivores and a weakly negative response for arboreal frugivore-insectivores, foliage gleaning insectivores, and raptors. Densities of trees and the percentage canopy cover were higher in the interior, and the ambient noise was lower. In contrast, arboreal nectarivore-insectivores responded positively to the forest edge, where there was a higher vegetation cover in the ground layer, a lower tree density, and a higher level of ambient noise.Conclusion: Planners should avoid road development in forests of high conservation value to reduce impacts on biodiversity. Where avoidance is impossible, a number of potential mitigation methods are available, but more detailed assessments of these are needed before they are applied in this region.
基金supported by the National Natural Science Foundation of China(Grant Nos.41476037,41606046&91228207)the Guangdong Natural Science Foundation(Grant No.2016A030310014)+2 种基金the Strategic Special Project of Chinese Academy of Sciences(Grant No.XDA11030104)the National Key Basic Research Program of China(Grant No.2013CB956102)Key Laboratory of Marine Mineral Resources,Ministry of Land and Resources(Grant No.KLMMR-2015-B-08)
文摘Overall abundance and species composition of radiolarian faunas were analyzed in surface sediment samples from representative areas of South China Sea, East China Sea, Sea of Japan, Sea of Okhotsk, Bering Sea, Philippine Sea, and the western boundary current regions of the North Pacific, in order to understand the biogeographic distribution ofradiolarians in the Northwest Pacific and explore its relationship with the main environmental factors and the North Pacific circulation. The results showed that radiolarians in the Northwest Pacific surface sediments can be divided into two large biogeographic provinces---cluster A and cluster B. Cluster A is characterized by the dominance of warm-water species and distributed primarily in tropical and subtropical seas with high radiolarian abundance and diversity; whereas cluster B is predominated by cold water species and distributed mainly in the Arctic and subarctic seas with comparably low abundance and diversity. Cluster A is further divided into five subclusters, AI to A5, which correspond to East China Sea, Philippine Sea, South China Sea, Sea of Japan, and Kuroshio Current, respectively; cluster B is divided into three subclusters, B1 to B3, which correspond to Sea of Okhotsk, Bering Sea, and subarctic gyre area, respectively. Based on the relationships between radiolarian faunas and major environment parameters in different biogeographic provinces, we suggest that the sea surface temperature （SST） and sea surface salinity （SSS） are primary factors that influence productivity, composition, and distribution pattern of the radiolarian fauna in the Northwest Pacific regions, while water depth is likely responsible for regional differences in the radiolarian fauna in each marginal sea. In addition, according to the distribution and abundance patterns of common radiolarian species in different areas, we identified five special radiolarian assemblages, which may be used as indicators for main Kuroshio Current, Kuroshio-East China Sea Branch, Kuroshio-South China Sea Branch, Tsushima Current, and Oyashio Current water masses.
