Rapid extinction of the moas (Aves: Dinornithiformes): model, test, and implications

A Leslie matrix population model supported by carbon-14 dating of early occupation layers lacking moa remains suggests that human hunting and habitat destruction drove the 11 species of moa to extinction less than 100 years after Polynesian settlement of New Zealand. The rapid extinction contrasts with models that envisage several centuries of exploitation.     

Amazonia 1492: pristine forest or cultural parkland?

Archaeology and indigenous history of Native Amazonian peoples in the Upper Xingu region of Brazil reveal unexpectedly complex regional settlement patterns and large-scale transformations of local landscapes over the past millennium. Mapping and excavation of archaeological structures document pronounced human-induced alteration of the forest cover, particularly in relation to large, dense late-prehistoric settlements (circa 1200 to 1600 A.D.). The findings contribute to debates on human carrying capacity, population size and settlement patterns, anthropogenic impacts on the environment, and the importance of indigenous knowledge, as well as contributing to the pride of place of the native peoples in this part of the Amazon.     

赫哲族渔猎文化与自然资源保护的相关性

从文化与资源互动的视角探讨自然资源保护与渔猎文化的相关性,将赫哲族渔猎文化解析为宗教、图腾、聚落、村规民约、经济类型等特定的因子结构,运用AMOS7.0的研究方法,建立了结构方程模型。研究结果表明赫哲族渔猎文化与自然资源保护的拟合程度较高,二者是协同演化的共生关系。对推动赫哲族的传统文化的保护以及进一步推动野生动物的保护,即对生物多样性的保护有重要的作用。     

鳄蜥的现状与保护

鳄蜥是我国特有珍濒危物种。近１０多年来,鳄蜥栖息生境遭到严重破坏;同时由于乱捕滥猎,致使其分布面积由原来的３００ｋｍ＾２缩小到现在的２００ｋｍ＾２,种群数量由原来的３０００只下降到现在的不足１０００只,减少了７０％。为此,提出几点加强保护管理的对策。     

A multispecies overkill simulation of the end-Pleistocene megafaunal mass extinction

A computer simulation of North American end-Pleistocene human and large herbivore population dynamics correctly predicts the extinction or survival of 32 out of 41 prey species. Slow human population growth rates, random hunting, and low maximum hunting effort are assumed; additional parameters are based on published values. Predictions are close to observed values for overall extinction rates, human population densities, game consumption rates, and the temporal overlap of humans and extinct species. Results are robust to variation in unconstrained parameters. This fully mechanistic model accounts for megafaunal extinction without invoking climate change and secondary ecological effects.     

小河西文化生业模式初探

小河西文化是西辽河流域新石器时代较早阶段的文化遗存。通过对小河西文化的气候与环境、聚落、生产生活工具、动植物遗存和原始农业的分析来看,小河西文化的生业模式以渔猎采集为主,辅之以简单的农业为补充,其原始农业已经处于萌芽阶段。     

天津高校毕业生“就业成本”分析及对策研究

随着高校扩招,大学毕业生的就业形势变得越来越严峻。在就业过程中,毕业生为了提高就业的成功率,越来越重视自身包装、公关等方面的花费,就业成本引起了社会的关注。通过对天津10所高校2008届毕业生的调查与研究发现,学生的求职消费大干预估消费,大学期间的经济主要来源于家庭,求职信息主要来源于网络信息,不同的家庭条件决定了他们的求职理念。因此,学校应该改革现有教学和实习模式,加强毕业生诚信教育,加大学校就业指导和就业服务的力度,鼓励毕业生到西部和基层就业等,以降低大学生的就业成本。     

Amazonia through time: Andean uplift, climate change, landscape evolution, and biodiversity

The Amazonian rainforest is arguably the most species-rich terrestrial ecosystem in the world, yet the timing of the origin and evolutionary causes of this diversity are a matter of debate. We review the geologic and phylogenetic evidence from Amazonia and compare it with uplift records from the Andes. This uplift and its effect on regional climate fundamentally changed the Amazonian landscape by reconfiguring drainage patterns and creating a vast influx of sediments into the basin. On this "Andean" substrate, a region-wide edaphic mosaic developed that became extremely rich in species, particularly in Western Amazonia. We show that Andean uplift was crucial for the evolution of Amazonian landscapes and ecosystems, and that current biodiversity patterns are rooted deep in the pre-Quaternary.     

Whales before whaling in the North Atlantic

It is well known that hunting dramatically reduced all baleen whale populations, yet reliable estimates of former whale abundances are elusive. Based on coalescent models for mitochondrial DNA sequence variation, the genetic diversity of North Atlantic whales suggests population sizes of approximately 240,000 humpback, 360,000 fin, and 265,000 minke whales. Estimates for fin and humpback whales are far greater than those previously calculated for prewhaling populations and 6 to 20 times higher than present-day population estimates. Such discrepancies suggest the need for a quantitative reevaluation of historical whale populations and a fundamental revision in our conception of the natural state of the oceans.     

稻田福寿螺发生为害的特点及综合防治技术

福寿螺对水稻的为害十分严重。文章介绍福寿螺的特征特性及发生规律,并在调查试验的基础上,总结出一套农业防治和药物防治相结合的综合防治福寿螺的办法。     

农村聚落空心化问题探讨——以太原盆地东南部为例

在实地考察的基础上 ,分析了农村聚落空心化的因素 ,主要归纳为人口和家庭因素、社会经济与收入、交通条件、制度因素和文化因素等 ,指出了农村聚落空心化造成的问题 ,并提出健全用地制度和提高人口素质是遏制农村聚落空心化的有效途径     

非粘性均匀沙群体沉降运动沉速公式的研究

从相对运动的观点出发,将非粘性均匀泥沙群体沉降运动概化为上升水流在悬浮颗粒层内的运动,通过量纲分析和动平衡状态受力分析,建立了泥沙群体沉降运动中阻力系数和雷诺数的表达式,并分别建立了层流区和紊流区均匀沙群体沉速的理论公式,其结构形式与目前常用的经验公式较为一致。应用实测资料对公式进行验证的结果表明,应用该理论公式的计算值与实测值吻合程度较好。同时通过分析讨论,提出了非均匀沙群体沉降速度问题的解决途径。     

青海云杉天然群体叶解剖结构的变异性及其与生态地理因子的相关性

以祁连山天然分布区的青海云杉为研究对象,调查了10个群体200个单株的8个针叶横切面解剖结构长度指标,研究了群体间和群体内的叶解剖结构变异程度,叶解剖结构性状间及其与地理、气候因子间的相关性,并运用聚类分析进行了群体分类.结果表明:祁连山青海云杉天然群体叶解剖结构的所有性状在群体间都存在着极显著差异,而在群体内差异不显著,即青海云杉叶解剖结构性状只在群体间存在广泛变异;各性状与年降水量呈显著或极显著的负相关,呈现出以年降水量变异为主的梯度规律性;通过对解剖指标的聚类分析可以将青海云杉10个群体划分为4个类群.     

A Review of the Ecology and Biology of Chinese Pangolin(Manis pentadactyla)

Chinese pangolin(Manis pentadactyla) has important value in Chinese medicine,economy and ecology.At present,Chinese pangolin is about to go extinct due to over hunting and habitat destruction,which has caused a dramatic decline in the wild population.Breeding Chinese pangolin in captivity is very difficult and has not succeeded yet.This paper is to review the wild population,habitat,foraging,activity rhythm,breeding and physiology of Chinese pangolin.It provides theoretical basis of ecology and biology for the protection and artificial domestication of Chinese pangolin.Meanwhile,given the demands of protection,future research directions are suggested.     

Demographic threats to the sustainability of Brazil nut exploitation

A comparative analysis of 23 populations of the Brazil nut tree (Bertholletia excelsa) across the Brazilian, Peruvian, and Bolivian Amazon shows that the history and intensity of Brazil nut exploitation are major determinants of population size structure. Populations subjected to persistent levels of harvest lack juvenile trees less than 60 centimeters in diameter at breast height; only populations with a history of either light or recent exploitation contain large numbers of juvenile trees. A harvesting model confirms that intensive exploitation levels over the past century are such that juvenile recruitment is insufficient to maintain populations over the long term. Without management, intensively harvested populations will succumb to a process of senescence and demographic collapse, threatening this cornerstone of the Amazonian extractive economy.     

Dissecting amazonian biodiversity

Biogeographical and biodiversity studies in Iowland Amazonian rain forests typically refer to observed or postulated distribution barriers such as past unfavorable climates, mountains, rivers, and river floodplains that divide the uniform tierra firme (noninundated) forest. Present-day ecological heterogeneity within tierra firme has hardly been discussed in this context, although edaphic differences are known to affect species distribution patterns in both inundated areas and tierra firme. Quantification of landscape heterogeneity in Peruvian Iowland Amazonia (500,000 kilometers squared), based on field studies and satellite image analysis, shows that Peruvian Amazonia is considerably more heterogeneous than previously reported. These observations have implications for the research, management, and conservation of Amazonian biodiversity.     

小偃麦渗入系F_2分离群体HMW-GS遗传分析

为了解小偃麦渗入系后代分离群体中高分子量麦谷蛋白的遗传规律,采用SDS-PAGE法分析了小偃麦渗入系CH03W006与普通小麦品种台长29杂交F2分离群体140个单株的高分子量麦谷蛋白亚基(HMW-GS)组成和遗传多样性。结果表明,2个亲本Glu-1位点不同亚基间不存在连锁关系;F2分离群体中HMW-GS遗传变异丰富,共出现19种HMW-GS组合类型,在Glu-A1,Glu-B1,Glu-D1位点上分别检测到3,10,4种不同的亚基类型,3个位点分别含有2*,7+8/13+16/17+18,5+10/5+12等丰富的优质亚基;聚类分析结果表明,F2分离群体与父本CH03W006聚为一类的HMW-GS类型最多,表明通过远缘杂交创造的新材料遗传基础丰富,且其后代群体HMW-GS的遗传存在偏父现象(Patroclinal Inheritance)。     

红皮云杉群体矿质营养特征的多样性

通过对青山林场红皮云杉10个群体苗木针叶矿物质元素的52个样本进行分析，结果表明，群体内存在丰富的变异，红皮去杉苗木针叶矿物质变异中，3.52%存在于群体间，群体内变异占96.48%。镁、铁、锌与苗木生物量相关密切；镁、镜、锰、磷、钾与亲本性状相关密切，其中，钾的质量分数与发芽率存在显著负相关；锌、磷、镁、氮与气候因子相关密切。方差分析结果表明，除磷、钾、锌群体间差异显著外，其余7个性状群体间差异均不显著，说明群体间苗木针叶矿物质质量分数差别很小。利用苗木针叶中矿物质质量分数磷、钾和锌3个元素进行聚类分析，将红皮云杉后代群体分为5类：白音敖包为一类，临江、天桥岭为一类，乌伊岭、大丰、友好为一类，穆棱、海林为一类，塔河、高峰为一类。     

Protein deficiency and tribal warfare in Amazonia: new data

Increasing numbers of anthropological studies about native Amazonian warfare and demographic practices attempt to explain these phenomena as competition over or a response to scarce game animals and other sources of high-quality protein. Recently completed field research among the Yanomam? Indians living at the Venezuela-Brazil border indicates that their protein intake is comparable to that found in highly developed industrialized nations and as much as 200 percent more than many nutritional authorities recommend as daily allowances. Recent data on other Amazonian tribes likewise fails to indicate a correlation between protein intake and intensity of warfare patterns.     

三峡库区农村移民安置带可持续发展研究

人口、资源、环境以及经济的协调发展,是实施国家"移得出、安得稳、逐步能致富"的移民政策的必然要求,也是国家可持续发展的内在需要。三峡库区农村移民安置带作为为三峡工程作出突出贡献的区域,在重庆作为全国城乡统筹试验区的背景下将如何发展,是目前亟待解决的问题。