基于Biolog-ECO技术不同退耕年限苜蓿地土壤微生物功能多样性分析

运用Biolog-ECO技术,分析半干旱黄土丘陵区不同生长年限紫花苜蓿（Medicago sativa）地和坡耕地土壤微生物功能多样性。结果表明：①在0～15 cm土层,平均吸光值总体变化趋势为生长旺盛苜蓿地显著优于极度退化苜蓿地、退化苜蓿地和坡耕地,坡耕地最差;在15～30 cm土层,平均吸光值总体变化趋势为极度退化...     

锡林郭勒盟不同草原地带湖泊环境变化规律研究

利用锡林郭勒草原2006年TM遥感影像数据,结合野外调查,在ArcGIS软件的支持下,将研究区面积大于5km2的湖泊-湿地复合体划分为湖泊、沼泽水体、裸地、裸滩与盐化地、湖滩湿地、典型湿地、地带性草原7种土地利用/覆盖类型,揭示不同草原地带湖泊-湿地复合体的结构变化规律。结果表明：在整个锡林郭勒草原范围内,湖泊相对集中...     

干旱胁迫下砂生槐、锦鸡儿的生理生化特性与抗旱性

以西藏半干旱区的两种豆科灌木为研究对象,采用盆栽控水干旱胁迫手段,比较和分析了砂生槐、矮锦鸡儿在持续水分胁迫条件下的生理响应。结果表明：随着干旱胁迫时间推移,土壤含水量不断下降,2种灌木体内水分饱和亏缺值均呈上升趋势,从上升速率和变化情况来看,砂生槐的叶片保水能力优于矮锦鸡儿;叶绿素a＋b值和叶绿素a/b值综合比较结果...     

巴丹吉林-腾格里沙漠间沙丘活化带发展过程及其驱动力分析

基于1989,1999年和2007年TM/ETM＋影像,从土地利用变化的视角分析巴丹吉林-腾格里沙漠间沙丘活化带的发展过程,并探讨沙丘活化带发展的驱动因素。分析表明：①1989-2007年,研究区沙地和耕地面积增加,草地、盐碱地和沼泽地面积减少,景观破碎化程度加剧,沙地斑块质心向西北偏移,即腾格里沙漠西北缘向巴丹吉林沙...     

The Vertical Distribution of Soil Seed Bank and Its Restoration Implication in an Active Sand Dune of Northeastern Inner Mongolia,China

Although the functions and characteristics of soil seed banks in topsoil layers have been described for various ecosystems, the spatiotemporal pattern of the seed bank in deep soil and its ecological implications for vegetation restoration of active sand dune have not been fully explored. In 2007 and 2008, seed densities with regard to dune position, soil depth and season were investigated on an active and a stabilized sand dune of northeastern Inner Mongolia, China. Seeds in the 0–10 cm topsoil layer accounted for 60% of total soil seed bank on the stabilized sand dune, while more than 40% of seeds were stored in the 50–100 cm layers on the active sand dune. Seed density declined significantly with soil depth on the stabilized sand dune, but it was relatively constant across the 0–100 cm soil profile on the active sand dune. Seed density fluctuated with soil depth on the active sand dune suggesting that seeds were either relocated upward or downward over time. Seeds of annual non‐psammophytic species accounted for the majority of soil seed bank on the stabilized sand dune, while pioneer psammophytes contributed more to the soil seed bank of the active sand dune. Our data suggest that seeds in the deep soil layers of active sand dunes account for a large proportion of the whole soil seed bank. Because of the effect of wind erosion, seeds in deep soil could be gradually exposed to shallow soil layers and potentially contribute to population recruitment and vegetation restoration on active sand dunes. Copyright © 2015 John Wiley & Sons, Ltd.     

Spatial Assessment of Land Degradation Risk for the Okavango River Catchment,Southern Africa

The Okavango catchment in southern Africa is subject to environmental as well as socio‐economic transformation processes such as population growth and climate change. The degradation of soil and vegetation by deforestation and overgrazing is one of the downsides of this development, reducing the capacity of the land to provide ecosystem functions and services. In this study, climate simulations are brought together with secondary socioeconomic, pedologic and remote‐sensing data in a GIS‐based assessment of the factors commonly associated with land degradation risk. A high resolution overview is provided for decision‐makers and stakeholders in the region by identifying priority intervention areas where a long‐term decline in ecosystem function and land productivity is most likely to occur. The approach combines 19 risk factors into seven individual ratings for topography, landcover, soil, demography, infrastructure, livestock pressure and climate. These ratings are then weighted and combined into an integrated degradation risk index (DRI). The results show that the land degradation risk is quite heterogeneously distributed in the study area and caused by different factors. Three hot‐spots are identified and compared, one of which is in the far northwestern part of the catchment, one around the local center Rundu and one on the outskirts of the Okavango Delta. We conclude that the approach is suitable to give an overview on degradation risk in the study area, although the classification process is a crucial procedure that should be standardized for further research. Copyright © 2015 John Wiley & Sons, Ltd.     

渭南市渭北黄土高原沟壑区侧柏造林试验

在渭南市渭北黄土高原沟壑区进行了侧柏不同苗木类型、不同苗龄的造林效果对比试验研究,试验结果表明:在黄土高原干旱沟壑区造林宜选用定植培育1a、苗高0.8~1.0m的侧柏容器苗,较裸根苗可提高成活率37.3个百分点;选用定植培育2a、苗高1.8~2.0m的侧柏苗,要带直径和高度不小于20cm的土球,较不带土球苗提高成活率40个百分点;栽后截除苗木顶梢和茎干枝叶的一部分,较不截可提高栽植成活率26.8个百分点。     

中日两国地区旅游形象设计比较研究及其对我国的启示

指出了地区旅游形象设计不仅仅有助于宣传当地旅游形象,而且有助于扩大本地的知名度,增进人们对本地的好感。为此,很多国家和地区都非常重视旅游形象的设计。从中国和日本的情况来看,由于传统文化思想、审美能力、设计人员的阅历和艺术创造观等诸多方面的差异,使得两国在旅游形象主题词、形象Logo和宣传口号的设计方面出现了不同的特色。针对两国已经公布的地区旅游形象设计进行了深入地剖析与阐述。通过比较研究,有助于两方取长补短,提高旅游形象设计水平,从而更好地开展宣传和扩大相关地区的知名度。     

西北地区生态环境与植被恢复重建问题探析

本文通过对西北地区生态环境问题形成的历史原因及现状分析,得出该区域主要的生态环境问题包括森林和草原生态破坏、水资源和水生态破坏、水土流失和土地荒漠化等方面。同时,依据该区域生态环境脆弱特性及植被在生态环境建设中的恢复机理,提出较为具体的植被恢复措施,试图为西北地区生态环境的恢复重建提供参考。     

黄土丘陵区沙棘林几个水分生理生态特征研究

为探讨沙棘对半干旱黄土丘陵区水分条件的适应性,1998年对沙棘的水分生理生态及抗旱性进行了分析研究.试验结果表明(1)沙棘适应半干旱黄土丘陵区生境形成了耐旱、御旱的双重抗旱方式.在旱季,沙棘体内束缚水含量随干旱加剧而上升,束缚水与自由水比值随干旱加剧而增大,叶片维持较高的含水量,蒸腾减弱,叶水势降低,临界饱和亏增大,表现出较强的抗旱性.(2)沙棘光合速率具明显的日变化,1000 1200出现第1次峰值,1400 1500出现第2次峰值.沙棘光合速率与环境因子(气温、相对湿度和光合有效辐射)间有显著的相关关系,相关系数为0.8466 0.9351,其中光合有效辐射对光合速率影响最显著,气温次之,相对湿度最小;沙棘光合速率与气孔导度及细胞间CO2浓度间有十分显著的相关关系,相关系数为0.9852 0.9856.(3)沙棘蒸腾速率与气孔导度具明显的日变化,两者的变化趋势相似,5、7月日变化曲线呈单峰型,6、8、9月日变化曲线呈双峰型.在生长季(5-