Anthropogenic activities may affect species diversity and community structure.Butterfly species diversity in relation to human-impact gradient was evaluated in the Baruipur subdivision,outskirts of Kolkata metropolis,...Anthropogenic activities may affect species diversity and community structure.Butterfly species diversity in relation to human-impact gradient was evaluated in the Baruipur subdivision,outskirts of Kolkata metropolis,West Bengal,India as a model geographic area.Four study sites situated in bird sanctuaries,rural,suburban and urban areas with different levels of anthropogenic disturbances were selected to assess the human impact on butterfly diversity.A total of 80 butterfly species were recorded during the entire study period with the sanctuary(with minimal anthropogenic disturbance)showing the highest species richness(73)followed by rural(62),suburban(54)and urban(36)study sites indicating a strong negative impact of anthropogenic disturbance on butterfly species diversity.Butterfly species diversity varied significantly among different habitats(p˂0.001).The relative abundance of butterflies also varied seasonally.It is apparent that the area under the present study is able to sustain diverse butterfly species provided natural habitats are protected from anthropogenic disturbances and steps are taken to increase urban greenery to support butterfly diversity and consequent ecosystem services.展开更多
为清晰阐明钝性弹道冲击下人体头部的受损机理,基于THUMS(Total Human Model for Safety)模型,通过材料参数优化、比例缩放及流固耦合方法,构建符合中国50百分位成年男性头部特征的有限元模型。以LS-DYNA(Livermore Software Technology...为清晰阐明钝性弹道冲击下人体头部的受损机理,基于THUMS(Total Human Model for Safety)模型,通过材料参数优化、比例缩放及流固耦合方法,构建符合中国50百分位成年男性头部特征的有限元模型。以LS-DYNA(Livermore Software Technology Corporation's Dynamic Analyzer)软件为仿真平台,采用任意拉格朗日-欧拉算法定义脑脊液流体特性,优化颅骨与脑组织的弹塑性材料参数,并通过网格变形技术实现头部尺寸与解剖结构的本土化适配。选取前额、顶壁、枕部及后窝等典型易损区,对比Nahum尸体实验及THUMS模型数据,验证模型的生物力学响应。研究结果表明:改进模型在易损区域的颅内压峰值分别为150 kPa、75 kPa、53 kPa及69 kPa,与实验数据误差为4%~10%,且动态响应曲线形态一致;脑组织最大von Mises应力(29.5 kPa)与颅骨主应力(18.7 kPa)均接近Marjoux和Yoganandan仿真实验阈值,证实模型可有效预测颅脑损伤风险。结合北约AEP-103标准评估表明,典型冲击下前额颅内压峰值达511.1 kPa,远超颅骨骨折阈值(150 kPa),凸显现有防护装备的优化需求。该模型应用性强,可为钝性弹道冲击下的头部损伤评估与安全防护提供方法参照和理论支撑。展开更多
Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no study to date has evaluated its impacts on the region’s mammalian fauna. For one year we carried out diurnal and noctu...Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no study to date has evaluated its impacts on the region’s mammalian fauna. For one year we carried out diurnal and nocturnal surveys using the Line Transect method in seven forest fragments varying from 7.32 ha to 469.76 ha, within a 4000 ha forest island archipelago, in Pernambuco State, Atlantic forest of northeastern Brazil. We calculated species density, population size, biomass and synergetic biomass, and recorded direct and indirect human impacts along the study transects. We recorded 44 mammalian species, of which 45.5% (n = 20) went extinct through hunting. The smallest forest fragment had the lowest richness, diversity, population size, and total biomass. It also had no synergetic biomass. The largest fragment had the highest richness, total density, and population size. There was a statistically significant relationship between fragment area and number of gunshots heard and suspended hunting platforms found;between population size and gunshots heard, suspended hunting platforms, free-roaming and feral dogs, and between total density and free-roaming and feral dogs. After more than 500 years of colonization hunting is still devastating, with larger fragments being linked to more hunters. Higher mammal abundances attracted more free-roaming and feral dogs, which have adapted to hunt wildlife on their own. Unless we protect every single forest fragment and create sustainable landscapes, we will not be able to save this hotspot’s hotspot.展开更多
文摘Anthropogenic activities may affect species diversity and community structure.Butterfly species diversity in relation to human-impact gradient was evaluated in the Baruipur subdivision,outskirts of Kolkata metropolis,West Bengal,India as a model geographic area.Four study sites situated in bird sanctuaries,rural,suburban and urban areas with different levels of anthropogenic disturbances were selected to assess the human impact on butterfly diversity.A total of 80 butterfly species were recorded during the entire study period with the sanctuary(with minimal anthropogenic disturbance)showing the highest species richness(73)followed by rural(62),suburban(54)and urban(36)study sites indicating a strong negative impact of anthropogenic disturbance on butterfly species diversity.Butterfly species diversity varied significantly among different habitats(p˂0.001).The relative abundance of butterflies also varied seasonally.It is apparent that the area under the present study is able to sustain diverse butterfly species provided natural habitats are protected from anthropogenic disturbances and steps are taken to increase urban greenery to support butterfly diversity and consequent ecosystem services.
文摘Although hunting in the north-eastern Atlantic forest of Brazil began more than 500 years ago, no study to date has evaluated its impacts on the region’s mammalian fauna. For one year we carried out diurnal and nocturnal surveys using the Line Transect method in seven forest fragments varying from 7.32 ha to 469.76 ha, within a 4000 ha forest island archipelago, in Pernambuco State, Atlantic forest of northeastern Brazil. We calculated species density, population size, biomass and synergetic biomass, and recorded direct and indirect human impacts along the study transects. We recorded 44 mammalian species, of which 45.5% (n = 20) went extinct through hunting. The smallest forest fragment had the lowest richness, diversity, population size, and total biomass. It also had no synergetic biomass. The largest fragment had the highest richness, total density, and population size. There was a statistically significant relationship between fragment area and number of gunshots heard and suspended hunting platforms found;between population size and gunshots heard, suspended hunting platforms, free-roaming and feral dogs, and between total density and free-roaming and feral dogs. After more than 500 years of colonization hunting is still devastating, with larger fragments being linked to more hunters. Higher mammal abundances attracted more free-roaming and feral dogs, which have adapted to hunt wildlife on their own. Unless we protect every single forest fragment and create sustainable landscapes, we will not be able to save this hotspot’s hotspot.
