Climate change and sandy land development in Qinghai Lake Watershed, China

The Qinghai Lake Watershed, containing the largest saline lake in northwest of China, has suffered from severe sandy land development in recent years. This paper analyzes its daily precipitation, temperature, and wind from 1958 to 2001, and the spatial and temporal distributions of sandy land through the interpretation of remote sensing images covering four years (1977, 1987, 2000, and 2004). Results showed that since the middle of the 1960s, the daily precipitation (P) of 0<P⩽5 mm decreased, while the P>20 mm increased significantly (S<0.05) in their annual total amounts and days. The maximum daily precipitation also increased significantly. Both the maximum dry spell and the total dry spell of more than ten days had a significant upward trend. Since the beginning of the 1960s, all the extremely high, extremely low and mean temperatures increased significantly (S<0.01), at a rate of 0.1°C/10a, 0.2°C/10a, and 0.2°C/10a, respectively. The days with extremely high temperature had a significant upward trend, while the days with extremely low temperature had a significant downward trend. The Qinghai Lake was significantly shrinking (S<0.01) and provided abundant sediments for Aeolian erosion. The NNW wind prevailed in the watershed, and the largest scale wind was from the west and concentrated on the dry months. As a result, the sandy land was mainly born on the east bank of Qinghai Lake. The total sandy land area in the watershed had grown from 587.4 km², 660.7 km², 697.6 km² to 805.8 km², accordingly, its area percentage growing from 2.0%, 2.2%, 2.4% to 2.7%, respectively.     

宁夏盐池封育区植物特征值及多样性影响

封育措施是一种主要的草场恢复和重建的措施。通过对半干旱沙地老封育、新封育和对照区的比较分析,量化了不同封育措施下植被变化。对3种封育措施群落组成和生物多样性的分析结果表明,封育改变了群落的组成成分并增加了生物多样性,同时对群落植物的生活型、饲用价值分析计算结果则显示,老封育的群落植物逐渐向多年生发展,放牧价值开始降低,而对照区则明显处于一种非平衡的稳定状态。从3种措施植被的盖度、高度、生物量和饲用价值来看,老封育区均低于新封育区和对照区,表明长期封育不利于促进并提高草场的放牧利用价值。     

Predicting the Impact of Sea-Level Rise on Caribbean Sea Turtle Nesting Habitat

Abstract:  The projected rise in sea level is likely to increase the vulnerability of coastal zones in the Caribbean, which are already under pressure from a combination of anthropogenic activities and natural processes. One of the major effects will be a loss of beach habitat, which provides nesting sites for endangered sea turtles. To assess the potential impacts of sea-level rise on sea turtle nesting habitat, we used beach profile measurements of turtle nesting beaches on Bonaire, Netherlands Antilles, to develop elevation models of individual beaches in a geographic information system. These models were then used to quantify areas of beach vulnerable to three different scenarios of a rise in sea level. Physical characteristics of the beaches were also recorded and related to beach vulnerability, flooding, and nesting frequency. Beaches varied in physical characteristics and therefore in their vulnerability to flooding. Up to 32% of the total current beach area could be lost with a 0.5-m rise in sea level, with lower, narrower beaches being the most vulnerable. Vulnerability varied with land use adjacent to the beach. These predictions about loss of nesting habitat have important implications for turtle populations in the region.     

高寒沙区两种典型固沙植物改良土壤的策略

植被恢复与重建是退化土地生态修复的重要途径,植物与土壤环境的关系一直是热点科学问题,但对高寒沙区尚缺乏系统性的研究。为探明不同沙生植物对高寒沙地土壤的改良策略,以青海共和盆地中间锦鸡儿(Caragana intermedia)和乌柳(Salix cheilophila)两种典型固沙植物为研究对象,通过对比细根分布规律分析其环境适应性,结合林地土壤物理性质、有机碳含量和土壤含水量等要素,分析两种植物对土壤的改良作用。结果表明,(1)两种植物的细根主要集中在0-60 cm土层,中间锦鸡儿水平方向分布更多,且细根平均生物量密度和有机碳含量都高于乌柳。(2)乌柳人工林各深度土壤有机碳密度均高于中间锦鸡儿,其累计百分比在0-40 cm土层较高,中间锦鸡儿在40-120 cm较高。(3)两种人工林的土壤容重、最大持水量和毛管持水量均值差异不显著。中间锦鸡儿林地土壤容重在0-40 cm土层大于乌柳,在40-120 cm小于乌柳;其最大持水量和毛管持水量在0-60 cm小于乌柳,在60-120 cm大于乌柳。(4)两种人工林土壤含水量和土壤温度都呈表层高,随土壤深度递减趋势。乌柳林地各深度土壤含水量均高于中间锦鸡儿,土壤温度均低于中间锦鸡儿。研究表明,中间锦鸡儿的环境适应性和固沙能力较强,倾向于深层土壤改良和固碳策略;乌柳人工林的固碳作用和涵养水源能力较强,倾向于表层土壤改良和固碳策略;同时,两种人工林都倾向于表层保水的策略。该文通过对比分析不同沙生植物改良土壤的策略,为长期研究高寒沙区生态修复与优良固沙植物筛选等工作提供理论依据。     

Sustainability of sand dune restoration along the coast of the Tyrrhenian sea

This study reports the results of restoration management on sand dune environments along the coastal belt of the Castelporziano nature reserve (Rome, Italy) and the subsequent monitoring phases to test the sustainability of the ‘soft techniques’ applied. In the area concerned, over a length of ca. 3 km, 40 dunes were built up along with three belts located at <40 m, 40–70 m, and >70 m, respectively, from the shoreline. On each of 38 dunes 20 individuals ofAmmophila littoralis were planted; this species is one of the local autochthonous species considered particularly suitable for stabilizing sand dunes. After one year, two years and five years, respectively the changes in height and surface of each dune, the survival rates ofA. littoralis, and its changes in cover, the appearance of new shoots and the establishment of new species were observed. A progressive increase in species number, which five years after the restoration amounted to about 60% of those characterizing the natural dunes, was reported indicating a progressive trend towards populations similar to natural ones. In the colonization of new species there is a prevalence of theSporobolus-Elymetum farcti and theSalsolo Kali-Cakiletum maritimae association, while the species established successively refer to theEchinophoro spinosae-Ammophiletum arundinaceae association and theCrucianellion maritimae alliance as occurring in natural successions. This succession runs parallel to the natural dune colonization processes. In particular, the data regarding survival, cover and number of vegetative shoots indicate that the dune belt between 40 and 70 m from the sea is the one most suitable for restoration. Some changes in dune morphology was observed: the height of the artificial dunes tended to decrease considerably in the five years of observation, whereas a progressive increase in their surface area was observed. During the study period.A littoralis favoured the establishment of new species, but as yet exercises no action on increasing dune height.     

内蒙古西乌珠穆沁旗伏沙地土壤环境粒度特征分析

通过对西乌珠穆沁旗境内不同类型伏沙地的土壤剖面特征和土壤粒径的分析认为:伏沙地土壤具有两层结构,其平均粒径大于地带性土壤.腐殖质层从上至下的粒径变化是先减小后增大.由松散的沙物质组成的母质层能够提供充足的水分,促进了矿物质的循环,使伏沙地的养分输出加快,不利于积累.良好的通气状况便有机物质矿化速度加快,不利于腐殖质的积累.     

江苏省沿江高沙土地区种植业可持续发展的技术途径研究

根据多年的生产实践经验和定位试验结果，提出了江苏省沿江高沙土地区多熟种植制、合理轮耕制、用养结合的培肥制和高产高效的栽培制相结合的种植业可持续发展的一体化技术体系，研究结果对我国中低产土壤地区种植业的持续发展具有重要意义。     

Nitrate leaching in agriculture to upper groundwater in the sandy regions of the Netherlands during the 1992–1995 period

The Dutch National Monitoring Programme for Effectiveness of the Minerals Policy (LMM) was initiated to allow detection of a statutory reduction in nitrate leaching caused by a decreasing N load. The starting point, or baseline, was taken as the nitrate concentration of the upper metre of groundwater sampled on 99 farms in the 1992–1995 period in the sandy areas of the Netherlands, where predominantly grass and maize grow. We found here that a reduction in nitrate leaching of more than 20% in future would almost certainly be detected with the LMM. Detecting downward trends due to decreasing N load will require nitrate concentrations to also be related to soil drainage, precipitation excess leading to groundwater recharge and to location. Furthermore, we found that about 16% of the N load in the Dutch sandy regions was being leached to the upper metre of groundwater in the 1992–1995 period. The critical N load in approximately 1990 for exceeding the EC limit value for nitrate, NO₃, (50 mg L^–1) in the upper metre of groundwater for the mean situation for grassland, maize and arable land in the sandy area was found to be 210 kg ha^–1 a^–1. Because manure management has been altered, the critical load found will be lower than the current critical load .     

榕江入海口自然沙滩微型塑料污染调查研究

1920s至今,塑料产业发展迅猛,海洋塑料污染问题日益严重.关于微型塑料(尺寸小于5 mm)对海洋生态系统的危害近年来受到国际社会的广泛关注.目前,我国关于河口和海岸带微型塑料的污染调查研究相对较少,开展相关研究将有利于海洋生态系统的管理、保护与健康.因此,本文以粤东第二大河流(榕江,汕头)入海口附近的自然沙滩为研究区域,选择榕江主干入海口、支流入海口和偏远海岸3个不同的区域,布设6个采样站位,调查和研究高潮线上部中小型塑料垃圾的组成、分布和来源.结果表明:榕江入海口自然沙滩废塑料的主要成分为塑料碎片(60%)、泡沫聚苯乙烯(27%)和前体颗粒(13%);各沙滩废塑料的平均密度为1067.67个·m-2,与世界其它地区同类的研究相比处于中等偏上的水平;废塑料的尺寸以直径小于5 mm的微型塑料为主,数量占总数的72%;微型塑料密度和塑料总密度在不同采样区域都呈现相同的趋势,即支流入海口附近海滩主干入海口附近海滩偏远海滩.对微型塑料的来源也作了初步探讨,河流上游塑料污染、河口附近城市的生活塑料垃圾排放及海上渔业活动是海滩微型塑料的主要潜在来源.     

Evaluation of beach quality as perceived by users

Recreational beaches are strategic ecosystems for tourism and should be used in a sustainable manner. We studied three beaches in the municipality of Guaymas (NW Mexico), in order to assess their beach quality and identify key management issues. The evaluation was based on the perceptions of users concerning: (1) the user profile; (2) the recreational habits of users; and (3) the biophysical characteristics, infrastructure, services, and cleanliness of each beach. The results showed that the beaches were of different quality. The key management issues identified were the need to design and apply specific management programs for each beach, specifically in regards to improving infrastructure and services, and obtaining certification as a sustainable beach. The evaluation of the beaches as perceived by users suggests that it would be useful to assess beach quality in order to support management goals and be applicable to other beaches, both nationally and internationally.