期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
1348年宁夏应理州汉语、蒙古语双语碑新诠
1
作者 党宝海 《西部蒙古论坛》 2022年第4期31-37,126,共8页
利用清代拓片,1348年宁夏路应理州汉语、蒙古语双语碑的碑文被重新释读。有别于柯立夫等学者的研究,第二行蒙古文的两个单词分别读作uran和?asaγulu,而非ün和ayaγ。由此,整个蒙古文的文意和排序得到新的解释。
关键词 宁夏应理州 汉语、蒙古语 双语碑 新释读
下载PDF
尘封中卫的九曲古渡
2
作者 张晓磊 《国土资源科普与文化》 2019年第1期50-52,共3页
中卫古为塞上名城,是黄河九渡之一的渡口要衢。古代在中卫一带有许多渡口,像冰沟渡、沙坡渡、泉眼山渡、常乐渡、永康渡、张义渡,黄河九渡当是指这一带渡口。塞上名城军事要津汉武帝元狩二年(公元前121年),西汉收复河西。'初置四郡&... 中卫古为塞上名城,是黄河九渡之一的渡口要衢。古代在中卫一带有许多渡口,像冰沟渡、沙坡渡、泉眼山渡、常乐渡、永康渡、张义渡,黄河九渡当是指这一带渡口。塞上名城军事要津汉武帝元狩二年(公元前121年),西汉收复河西。'初置四郡',由张骞开创的'丝绸之路'完全被打通,汉王朝在河西和河朔地区的大举屯田移民随之展开;与西域各国之间的交流进一步扩大. 展开更多
关键词 黄河两岸 应理州 中卫沙坡头 西夏地形图 泉眼山 河西走廊
原文传递
Managing hybridization of a recovering endangered species: The red wolf Canis rufus as a case study 被引量:1
3
作者 Eric M. GESE Fred F. KNOWLTON +7 位作者 Jennifer R. ADAMS Karen BECK Todd K. FULLER Dennis L. MURRAY Todd D. STEURY Michael K. STOSKOPF Will T. WADDELL Lisette P. WAITS 《Current Zoology》 SCIE CAS CSCD 2015年第1期191-205,共15页
Hybridization presents a unique challenge for conservation biologists and managers. While hybridization is an important evolutionary process, hybridization is also a threat formany native species. The endangered speci... Hybridization presents a unique challenge for conservation biologists and managers. While hybridization is an important evolutionary process, hybridization is also a threat formany native species. The endangered species recovery effort for the red wolf Canis rufus is a classic system for understanding and addressing the challenges of hybridization. From 1987-1993, 63 red wolves were released from captivity in eastern North Carolina, USA, to establish a free-ranging, non-essential experimental population. By 1999, managers recognized hybridization with invasive coyotes Canis latrans was the single greatest threat to successful recovery, and an adaptive management plan was adopted with innovative approaches for managing the threat of hybri- dization. Here we review the application and results of the adaptive management efforts from 1993 to 2013 by comparing: (1) the numbers of wolves, coyotes, and hybrids captured, (2) the numbers of territorial social groups with presumed breeding capabili- ties, (3) the number of red wolf and hybrid litters documented each year and (4) the degree of coyote introgression into the wild red wolf gene pool. We documented substantial increases in the number of known red wolves and red wolf social groups from 1987-2004 followed by a plateau and slight decline by 2013.The number of red wolf litters exceeded hybrid litters each year and the proportion of hybrid litters per year averaged 21%. The genetic composition of the wild red wolf population is estimated to include 〈 4% coyote ancestry from recent introgression since reintroduction. We conclude that the adaptive management plan was effective at reducing the introgression of coyote genes into the red wolf population, but population recovery of red wolves will require continuation of the current management plan, or alternative approaches, for the foreseeable future. More broadly, we discuss the lessons learned from red wolf adaptive management that could assist other endangered species recovery efforts facing the challenge of minimizing hybridization [Current Zoology 61 (1): 191-205, 2015 ]. 展开更多
关键词 CANID CONSERVATION GENETICS Hybrid Management
原文传递
Scale Effects of Geographical Soil Datasets on Soil Carbon Estimation in Louisiana,USA:A Comparison of STATSGO and SSURGO 被引量:4
4
作者 B. ZHONG Y. J. XU 《Pedosphere》 SCIE CAS CSCD 2011年第4期491-501,共11页
Estimation of soil organic carbon (SOC) pools and fluxes bears large uncertainties because SOC stocks vary greatly over geographical space and through time. Although development of the U.S. Soil Survey Geographic Da... Estimation of soil organic carbon (SOC) pools and fluxes bears large uncertainties because SOC stocks vary greatly over geographical space and through time. Although development of the U.S. Soil Survey Geographic Database (SSURGO), currently the most detailed level with a map scale ranging from 1:12 000 to 1:63 360, has involved substantial government funds and coordinated network efforts, very few studies have utilized it for soil carbon assessment at the large landscape scale. The objectives of this study were to 1) compare estimates in soil organic matter among SSURGO, the State Soil Geographic Database (STATSGO), and referenced field measurements at the soil map unit; 2) examine the influence of missing data on SOC estimation by SSURGO and STATSGO; 3) quantify spatial differences in SOC estimation between SSURGO and STATSCO, specifically for the state of Louisiana; and 4) assess scale effects on soil organic carbon density (SOCD) estimates from a soil map unit to a watershed and a river basin scale. SOC was estimated using soil attributes of SSURGO and STATSGO including soil organic matter (SOM) content, soil layer depth, and bulk density. Paired t-test, correlation, and regression analyses were performed to investigate various relations of SOC and SOM among the datasets. There were positive relations of SOC estimates between SSURGO and STATSGO at the soil map unit (R2 = 0.56, n = 86, t = 1.65, P = 0.102; depth: 30 cm). However, the SOC estimated by STATSGO were 9%, 33% and 36~ lower for the upper 30-cm, the upper l-m, and the maximal depth (up to 2.75 m) soils, respectively, than those from SSURGO. The difference tended to increase as the spatial scale changes from the soil map unit to the watershed and river basin scales. Compared with the referenced field measurements, the estimates in SOM by SSURGO showed a closer match than those of STATSCO, indicating that the former was more accurate than the latter in SOC estimation, both in spatial and temporal resolutions. Further applications of SSURGO in SOC estimation for the entire United States could improve the accuracy of soil carbon accounting in regional and national carbon balances. 展开更多
关键词 carbon accounting climate change GIS soil organic carbon soil organic matter
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部