初情懵懂示爱时

刺鱼:虽为花心丈夫,但是称职父亲 在我们这个蓝色星球的众多水域里,共生活着12种刺鱼.之所以被称为"刺鱼",是因为它们的脊背上或胸鳍间肯定都长有3到15根锋利的尖刺或硬骨刺.长3根刺的叫三刺鱼,长9根刺的叫九刺鱼,身上长刺最多的刺鱼可达15根硬刺.每年到了繁殖季节,刺鱼便从海洋中游到江河里去产卵.     

龙虾繁殖生物学及幼体培育研究进展

龙虾隶属于节肢动物门，甲壳纲，十足目，龙虾科，龙虾属。已知全球共有19个种类，我国沿海有中国龙虾（P．stimpsoni）、锦绣龙虾（P．ornatus）、波纹龙虾（P．homarus）、密毛龙虾（P．peni—cillatus）、日本龙虾（P．japonicus）、     

新疆生地所首次报道中国新疆普氏野马(Equus ferus przewalskii)重引入工作

正普氏野马曾广泛分布于中国新疆准噶尔盆地和蒙古国干旱荒漠草原地带,故又被称为准噶尔野马或蒙古野马。随着畜牧业快速发展、草原的过度开垦、矿业开采侵占和破坏野马的栖息地等多方面因素,普氏野马种群数量不断降低。最后一次野外观察到普氏野马是1969年在蒙古国Dzungarian戈壁。自此,普氏野马仅圈养于欧美等西方国家的动物园内。自1985-2005年,中国从西方动物园共引入24匹普氏野马,放入位于准噶尔盆地南缘的新疆吉木萨尔野马繁育中心。中国科学院新疆生态与地理研究所杨维康研究员课题组首次发表文章详细报     

Livestock-carrying capacity and overgrazing status of alpine grassland in the Three-RiverHeadwaters region,China简

The Three-River Headwaters region in China is an ecological barrier providing en- vironmental protection and regional sustainable development for the mid-stream and down- stream areas, which also plays an important role in animal husbandry in China. This study estimated the grassland yield in the Three-River Headwaters region based on MODIS NPP data, and calculated the proper livestock-carrying capacity of the grassland. We analyzed the overgrazing number and its spatial distribution characteristics through data comparison be- tween actual and proper livestock-carrying capacity. The results showed the following： （1） total grassland yield （hay） in the Three-River Headwaters region was 10.96 million tons in 2010 with an average grassland yield of 465.70 kg/hm2 （the spatial distribution presents a decreasing trend from the east and southeast to the west and northwest in turn）; （2） the proper livestock-carrying capacity in the Three-River Headwaters region is 12.19 million sheep units （hereafter described as ＂SU＂）, and the average stocking capacity is 51.27 SU [the proper carrying capacity is above 100 SU/km2 in the eastern counties, 60 SU/km2 in the cen- tral counties （except Madoi County）, and 30 SU/km2 in the western counties]; and （3） total overgrazing number was 6.52 million SU in the Three-River Headwaters region in 2010, with an average overgrazing ratio of 67.88% and an average overgrazing number of 27.43 SU/km2 A higher overgrazing ratio occurred in Tongde, Xinghai, Yushu, Henan and Z~kog. There was no overgrazing in Zhiduo, Tanggula Township and Darlag, Qumerleb and Madoi. The re- mainder of the counties had varying degrees of overgrazing.     

妨碍矿产资源国家所有权到位的两个问题值得关注

我国在《物权法》中把由矿产资源国家所有权派生的探矿权和采矿权列为依法保护的用益物权,为探矿权和采矿权的有偿出让或取得提供了法律依据。然而,近年来在矿政管理中出现了过度物权化和过度行政干扰的倾向性问题。本文在分析矿政管理中过度物权化和过度行政干扰的表现和后果以及过度物权化的认识根源和过度行政干扰的体制性根源的基础上提出了相关对策建议。     

全球变暖对海洋食物网的影响

想搞清全球变暖对海洋生命的影响是不容易的,因为情况很复杂。新的试验证明:在比较温暖、富含营养成分的水域中,位于海洋食物链最底层的浮游植物繁殖得较少;浮游动物则会加速繁殖,这可能对某些鱼类有利。食物网理论基于这样的一个设想:温度会影响以其     

气象因素对种猪繁殖性能的影响

1气温的影响1．1气温对公猪的影响成年公猪适宜的环境温度是18—20℃．若温度稍低,对公猪的繁殖性能影响不大,而高温对公猪影响较大。