干不死的卷柏

蕨类植物虽然不像生长在沙漠中的其它植物那样抗旱,但也有一些很耐旱的种类,卷柏就是其中的一种。 卷柏(Selaginella tamarisci-na),为卷柏科,卷柏属的一种矮小的草本植物。高5—20厘米,直立茎,顶端丛生小枝,小枝扇形或2—3回羽生,密生许多小鳞片,很像裸子植物柏科植物的叶。卷柏靠孢子繁殖,孢子叶卵状三角形,有龙骨状突起,孢     

棕色田鼠与沼泽田鼠犁鼻器和副嗅球的组织结构

用组织学方法研究了棕色田鼠(Microtus mandarinus)、沼泽田鼠(M．fastis)副嗅球和犁鼻器的结构及其在两种鼠间的差异，以此探讨两种田鼠的进化机制与适应功能。两种田鼠的犁鼻器位于鼻腔前端鼻中隔基部的两侧，呈管状结构；沿着犁鼻器的长轴犁鼻管呈现不同的形态学特征，犁鼻管直接开口于鼻腔，从前向后沿着长轴旋转，中间管壁(犁鼻粘膜)变成底部，侧面管壁(假覆层上皮)变成犁鼻管顶壁，最终犁鼻管变小成为一个腺体的分支，不同部位具有不同的组织学特征。通过选取中间相似部位对两种田鼠进行比较研究，发现棕色田鼠犁鼻粘膜比沼泽田鼠厚，而其长度却短于沼泽田鼠。棕色田鼠副嗅球颗粒细胞带宽和僧帽细胞带宽均大于沼泽田鼠，而带长却小于沼泽田鼠。相关分析发现，犁鼻器和副嗅球形态有一定的对应关系，这可能和两个结构之间存在着神经投射有关。棕色田鼠幼体的犁鼻粘膜、神经细胞核、假覆层上皮、血管面积均小于成体[动物学报49(2)：248—255，2003]。     

鱼鳞坑与覆盖组合措施对陕北旱作枣园土壤水分的影响

土壤水分是制约陕北红枣林健康生长的关键因子.通过土壤水分定位观测,研究不同鱼鳞坑与覆盖措施组合对陕北黄土丘陵区旱作枣园土壤水分的影响.结果表明: 鱼鳞坑+树枝覆盖、鱼鳞坑+秸秆覆盖、鱼鳞坑无覆盖处理下0～180 cm平均土壤含水量较裸地分别提高14.2%、9.4%、4.8%.不同处理在红枣生育期均能显著增加土壤表层(0～20 cm)和主要根系层(20～100 cm)土壤水分含量,其中,以鱼鳞坑+树枝覆盖处理效果最为显著.不同组合措施条件下,次降雨量对土壤水分的影响深度主要集中在100 cm以内,对深层土壤水分影响不显著.无覆盖鱼鳞坑措施在高、中、低水分状况下,各土层土壤水分与裸地无显著差异.在陕北旱作枣园,利用修剪枣枝进行覆盖在节省材料减少成本的同时,实现了保墒蓄水目标.     

鱼鳞坑与覆盖组合措施对陕北旱作枣园土壤水分的影响

土壤水分是制约陕北红枣林健康生长的关键因子.通过土壤水分定位观测,研究不同鱼鳞坑与覆盖措施组合对陕北黄土丘陵区旱作枣园土壤水分的影响.结果表明:鱼鳞坑+树枝覆盖、鱼鳞坑+秸秆覆盖、鱼鳞坑无覆盖处理下0~180 cm平均土壤含水量较裸地分别提高14.2%、9.4%、4.8%.不同处理在红枣生育期均能显著增加土壤表层(0~20 cm)和主要根系层(20~100 cm)土壤水分含量,其中,以鱼鳞坑+树枝覆盖处理效果最为显著.不同组合措施条件下,次降雨量对土壤水分的影响深度主要集中在100 cm以内,对深层土壤水分影响不显著.无覆盖鱼鳞坑措施在高、中、低水分状况下,各土层土壤水分与裸地无显著差异.在陕北旱作枣园,利用修剪枣枝进行覆盖在节省材料减少成本的同时,实现了保墒蓄水目标.     

中国薄叶卷柏复合群的物种划分

卷柏属(Selaginella)是石松类植物中最大的属, 也是分类难度较大的类群之一。该属的物种划分主要基于形态特征, 但许多近缘种在形态上很难区分。近年来, 已有大量分子证据被用于各植物类群的分类学研究, 但目前未发现一套适合卷柏属物种鉴定的分子标记。薄叶卷柏复合群(S. delicatula group)是卷柏属下鉴定较为困难的类群, 包括了薄叶卷柏(S. delicatula)、黑顶卷柏(S. picta)和瓦氏卷柏(S. wallichii) 3个物种, 主要分布于亚洲的热带和亚热带地区。为了探讨薄叶卷柏复合群内物种的亲缘关系和评估不同分子标记在卷柏属分类学研究中的应用价值, 本研究对该复合群物种进行广泛取样, 共收集到73个个体, 并选取3个叶绿体基因(rbcL, psbA和atpI)和2个核基因(26S nrDNA和pgiC)片段进行系统树的构建及叶绿体单倍型分析。研究发现, 基于叶绿体和核基因构建的系统发生关系存在冲突: 叶绿体基因树上薄叶卷柏个体分为两个分支(A和B), 薄叶卷柏B分支与薄叶卷柏A-S. picta分支呈姐妹关系, 并且rbcL单倍型分析结果也表明薄叶卷柏A和B两个分支存在明显分化; 而核基因结果则支持该复合群3个物种各自的单系性, 其中, S. delicatula分支与S. picta分支为姐妹群, S. wallichii与S. delicatula-S. picta分支为姐妹关系。在对复合群分布区大量标本的观察以及野外群体调查的基础上, 评估了植株茎和枝的分枝方式、孢子叶、营养叶(侧叶、中叶和腋叶)和孢子表面纹饰等形态性状的分类学价值。结果表明, 薄叶卷柏A和B分支的样本仅在植株分枝方式和大孢子表面纹饰上存在差异, 但无法依靠小孢子表面纹饰、孢子叶穗和营养叶形态等特征进行区分。基于现有证据, 薄叶卷柏复合群至少可划分为薄叶卷柏、黑顶卷柏和瓦氏卷柏3种, 但彻底澄清该复合群的物种划分还需要获取模式标本产地的材料和细胞学证据。最后, 建议在未来卷柏属的分类学研究集中于该属分类复杂的复合群, 结合使用形态学、细胞学、分子生物学(同时使用核基因和叶绿体分子标记)及地理分布等整合证据来进行物种划分。     

棕色田鼠和沼泽田鼠雄性社会行为与嗅觉相关脑区性激素受体表达之间的关系

应用行为聚焦取样观察和免疫组织化学相结合的方法 ,比较研究了棕色田鼠 (Microtusmandarinus)(n =15 )和沼泽田鼠 (M .fostis) (n =15 )在同种雄雄交往中的行为差异 ,及在雄雄交往前后雌激素 β受体(ERβ)和雄激素受体 (AR)表达的差异。在 2h的雄雄交往中 ,前 1h棕色田鼠对同性入侵者有较多的攻击和防御行为 ,后 1h攻击行为较少 ,沼泽田鼠前后 1h差异不大 ,整个 2h期间 ,棕色田鼠较沼泽田鼠对同性入侵者有较多的攻击、防御行为 ,较少的非社会行为。经过免疫组织化学检测 ,没有社会交往时棕色田鼠主嗅球系统投射区和犁鼻系统投射区ERβ免疫阳性细胞 (ERβ IRs)明显少于沼泽田鼠 ,且显色淡 ,AR免疫阳性细胞(AR IRs)在两种鼠间差异不大 ,且都明显少于各自的ERβ IRs。 2h交往后 ,棕色田鼠主嗅球投射区和犁鼻系统投射区的ERβ IRs细胞数明显少于交往前 ,AR IRs细胞数明显多于交往前 ;沼泽田鼠交往前与交往后ERβ IRs和AR IRs细胞数均无显著差异 ,且显著多于交往后棕色田鼠ERβ IRs细胞数 ,显著少于交往后棕色田鼠AR IRs细胞数。以上结果表明 :两种田鼠在社会交往中社会行为不同 ;ERβ的减少和AR的增多可能在社会识别及攻击行为中均起一定的作用 ,可能也是引起两种田鼠社会行为发生差异的原因之一     

卷柏科11种雌配子体形态发育的研究

本文用扫描电镜和光镜详细研究了人工培养的中国产卷柏科Selaginellaceae 11种卷柏的雌配子体的发育特点和形态特征,11种卷柏分别是卷柏Selaginella tamariscina(Beauv.)Spring小卷柏,S.helvetica(L.)Link,鹿角卷柏S.rossii(Bak.)Warb.,疏叶卷柏S.remotifolia Sp-ring,西伯利亚卷柏S.sibirica(Milde)Hieron,中华卷柏S.sinensis(Desv.)Spring,薄叶卷柏S.delicatula(Desv.)Alston,异穗卷柏S.heterostachys Bak.,细叶卷柏S.labordei Hieron。,伏地卷柏S.nippon-ica Fr.et Sav.和圆枝卷柏S.sanguinolenta(L.)Spring,在比较了每种雌配子体形态发育特点的基础上,讨论了卷柏科雌配子体在形态演化上的可能趋势,认为有“赤道轴缩减型”和“极轴缩减型”之分,这与根据孢子体将卷柏科分为Homoerphyllum和Heterophyllum两类的观点相吻合,并探讨了用雌配子体形态发育为卷柏类分组所能提供的依据。 其中9种系首次报道。     

魁舟蛾属一新种

棕魁舟蛾 Megashachia brunnea新种 翅展雄蛾69—77、雌蛾77—87毫米。触角干基部和背面灰白色,其余棕色;头和胸背(具冠形毛簇)棕色与灰白色混杂,其上分别有3、4条暗棕色横线;腹部背面和末端匙形毛簇暗褐色,具浅褐灰色中线,1—4节两侧后半部褐灰色,6—9节两侧各有一条黑棕色纵线,其中8—9节另有一条同样的短纵线,腹面灰褐色具黑棕色中线,基部中央两侧有一对褐黄色长刷形毛簇(有些标本藏在表面毛鳞的下方而不外露);前翅棕色,从近基部到近翅尖的后半部较暗,如呈一大三角形暗斑,中室至亚端线间的翅脉黑棕色,亚端线以外的翅脉褐     

单宁酸对棕色田鼠和小鼠食物选择、日食量和蛋白质消化率的影响

目的用不同浓度单宁酸（tannic acid,TA）处理后的花生喂养棕色田鼠（Lasiopodomys mandarinus）和小鼠（Mus musculus）,研究单宁酸对两种鼠食物选择倾向、食物摄入量、蛋白质消化率的影响。方法本研究的设计如下：1）选择一批棕色田鼠和小鼠,单笼饲养,自由饮水。用正常花生饲喂二周实验用棕色田鼠和小鼠,使其适应这种食物;2）随机选出棕色田鼠和小鼠各10只（雌雄各半）,单笼饲养。用经0%、5%、10%TA处理的花生饲喂供试鼠一周,观察和记录两种鼠对TA处理后花生的选择和取食特征;3）随机选出18只棕色田鼠和18只小鼠,单笼饲养,并各分为3组（每组均为6只）,按两种鼠分别命名为对照组、低单宁酸组、高单宁酸组,并分别用经0%、5%和10%TA处理的花生饲喂一周,测定两种鼠的食物摄入量;同时收集粪便,用凯氏定氮仪测定粗蛋白含量,计算蛋白质消化率。结果1）棕色田鼠和小鼠均优先选择无TA食物（P〈0.001）,二者间差异达显著性水平（P〈0.001）;2）食物中的TA降低棕色田鼠和小鼠的相对日食量（P〈0.001）和食物中蛋白质的消化率,随TA含量的升高,棕色田鼠和小鼠的相对日食量和蛋白质消化率均显著下降。结论TA降低棕色田鼠和小鼠的食物摄入量和食物中蛋白质的消化率。TA对鼠类的食物摄入量和蛋白质消化率的影响有种间差异性,小鼠对TA的适应性更强。     

江南卷柏Phi类谷胱甘肽S-转移酶的分子特性

谷胱甘肽S-转移酶(Glutathione S-transferase,GST)在帮助植物抵抗各种胁迫中发挥重要作用。该研究从江南卷柏Selaginella moellendorffii中克隆到两个Phi类GST基因,分别命名为Sm GSTF1和Sm GSTF2,两个基因均编码215个氨基酸残基的蛋白质。表达模式分析发现,这两个基因在江南卷柏根、茎和叶中均有表达。将这两个基因在大肠杆菌中诱导表达重组蛋白并纯化,酶学性质分析表明Sm GSTF1和Sm GSTF2对CDNB、NBD-Cl和NBC等3种底物都有活性。Sm GSTF1对Fluorodifen和Cum-OOH也有活性,而Sm GSTF2对它们没有活性。酶动力学分析表明Sm GSTF1和Sm GSTF2对GSH有较高的亲和力,而对CDNB的亲和力都相对较低。在不同p H及温度条件下对Sm GSTF1和Sm GSTF2重组蛋白进行活性测定,发现这两个蛋白在p H 7-8.5,45-55℃温度范围内有较高的催化活性。研究推测,Sm GSTF1和Sm GSTF2可能在江南卷柏的抗逆生理过程中有重要的作用。     

Diversity of desert rangelands of Tunisia

Plants are important components of any rangeland. However, the importance of desert rangeland plant diversity has often been underestimated. It has been argued that desert rangelands of Tunisia in good ecological condition provide more services than those in poor ecological condition. This is because rangelands in good condition support a more diverse mixture of vegetation with many benefits, such as forage for livestock and medicinal plants. Nearly one-quarter of Tunisia, covering about 5.5 million hectares, are rangelands, of which 87% are located in the arid and desert areas (45% and 42%, respectively). Here, we provide a brief review of the floristic richness of desert rangelands of Tunisia. Approximately 135 species are specific to desert rangelands. The predominant families are Asteraceae, Poaceae, Brassicaceae, Chenopodiaceae, and Fabaceae. These represent approximately 50% of Tunisian desert flora.     

Effects of Climate Change on Range Forage Production in the San Francisco Bay Area

The San Francisco Bay Area in California, USA is a highly heterogeneous region in climate, topography, and habitats, as well as in its political and economic interests. Successful conservation strategies must consider various current and future competing demands for the land, and should pay special attention to livestock grazing, the dominant non-urban land-use. The main objective of this study was to predict changes in rangeland forage production in response to changes in temperature and precipitation projected by downscaled output from global climate models. Daily temperature and precipitation data generated by four climate models were used as input variables for an existing rangeland forage production model (linear regression) for California’s annual rangelands and projected on 244 12 km x 12 km grid cells for eight Bay Area counties. Climate model projections suggest that forage production in Bay Area rangelands may be enhanced by future conditions in most years, at least in terms of peak standing crop. However, the timing of production is as important as its peak, and altered precipitation patterns could mean delayed germination, resulting in shorter growing seasons and longer periods of inadequate forage quality. An increase in the frequency of extremely dry years also increases the uncertainty of forage availability. These shifts in forage production will affect the economic viability and conservation strategies for rangelands in the San Francisco Bay Area.     

Carrying capacity in arid rangelands during droughts: the role of temporal and spatial thresholds

Assessing the carrying capacity is of primary importance in arid rangelands. This becomes even more important during droughts, when rangelands exhibit non-equilibrium dynamics, and the dynamics of livestock conditions and forage resource are decoupled. Carrying capacity is usually conceived as an equilibrium concept, that is, the consumer density that can co-exist in long-term equilibrium with the resource. As one of the first, here we address the concept of carrying capacity in systems, where there is no feedback between consumer and resource in a limited period of time. To this end, we developed an individual-based model describing the basic characteristics of a rangeland during a drought. The model represents a rangeland composed by a single water point and forage distributed all around, with livestock units moving from water to forage and vice versa, for eating and drinking. For each livestock unit we implemented an energy balance and we accounted for the gut-filling effect (i.e. only a limited amount of forage can be ingested per unit time). Our results showed that there is a temporal threshold above which livestock begin to experience energy deficit and burn fat reserves. We demonstrated that such a temporal threshold increases with the number of animals and decreases with the rangeland conditions (amount of forage). The temporal threshold corresponded to the time livestock take to consume all the forage within a certain distance from water, so that the livestock can return to water for drinking without spending more energy than they gain within a day. In this study, we highlight the importance of a time threshold in the assessment of carrying capacity in non-equilibrium conditions. Considering this time threshold could explain contrasting observations about the influence of livestock number on livestock conditions. In case of private rangelands, the herd size should be chosen so that the spatial threshold equals (or exceeds) the length of the drought.     

Unmanned aerial systems accurately map rangeland condition indicators in a dryland savannah

Dry savannahs are highly sensitive to climate change and under intense anthropogenic pressure. Therefore, the methods for assessing their status should be easy and repeatable. Monitoring through satellite data and field measurements are limited in accurately assessing the spatiotemporal dynamics of ecosystems. Fortunately, emerging technologies like Unmanned Aerial Systems (UAS) allow to transcend these limitations. But their calibration with field data for application in rangelands is still relatively new and less common than for example in precision agriculture. In this study we developed a drone-based workflow for mapping the condition of rangelands in dryland savannah. We evaluated how accurately and efficiently the two common indicators (i.e., potential forage biomass and rangeland cover type) of rangeland condition can be estimated from drone imagery across a range of conditions (i.e., highly degraded to healthy rangelands). To develop the drone-based potential forage biomass model we tested the accuracy of four vegetation indices to predict field biomass, with the optimized soil adjusted vegetation index (OSAVI) showing the highest prediction accuracy (R² = 0.89 and RMSE = 194.05). The OSAVI-based model yielded a significant strong relationship (R² = 0.80, p < 0.001) between predicted and field observed potential forage biomass across the rangeland system. For land cover, we applied a decision tree classification based on thresholds determined using data mining, with a mean overall accuracy of 95.8%. The drone-based estimates of bare cover, herbaceous cover and woody cover showed strong agreements (R² ranging between 0.86 and 0.97) with the two image-truthing methods (line-point intercept and visual estimations) tested. We show that the drone-based approach is more efficient, unbiased, and repeatable than the field methods. Based on these results, the drone-based workflow presented here offers a reproducible, accurate and efficient approach for near-real time monitoring of rangeland condition at a landscape level. This may assist with climate-adapted management to prevent further land degradation and associated threats to biodiversity and human livelihoods.     

Comparing socioeconomic vulnerability index and land cover indices: Application of fuzzy TOPSIS model and geographic information system

Vulnerability Assessment (VA) has numerous management implications, particularly for locating the most vulnerable areas affected by land cover degradation. This study aims to assess and compare the relationship between socioeconomic vulnerability (SEV) and land cover indices (LCIs) in summer rangelands (Natanz county) and winter rangelands (Aran-V-Bidgol county) in Isfahan Province, Iran. To assess the socioeconomic vulnerability index (SEVI), a survey was conducted. Based on the SEVI, summer and winter rangelands were classified and mapped using a combination of fuzzy TOPSIS model and geographic information system (GIS) techniques. Field research was conducted to estimate LCIs, including plant cover, plant yield, litter (dead biomass), sand and gravel, bare soil, and forage production. Finally, the correlations between SEVI and LCIs were verified, and the SEV of winter rangelands and summer rangelands was examined. Results showed the rangelands of Chah Robat, Bidhend, and Tar were the most vulnerable summer rangelands, while the rangelands of Chah Zard, Cheshmeh Sefid, and Kandeh Matin were the most vulnerable winter rangelands. Findings further revealed more LCIs, including total ground cover, the yield of shrubs, and total yield had a significant relationship with SEVI in summer rangelands compared to winter rangelands (yield of annual forbs and total yield). Moreover, there was a significant difference between SEVI, determined by the fuzzy TOPSIS model, in summer and winter rangelands. It can be concluded that while the fuzzy TOPSIS model and GIS can be used to gain a better understanding of VA, the type of rangeland has an impact on how well these techniques can assess the SEV of rangelands.     

六盘山林区几种土地利用方式下土壤活性有机碳的比较

 应用KMnO4氧化法测定分析了六盘山林区天然次生林（杂灌林、山杨（Populus davidanda）和辽东栎（Querces liaotungensis）林）、农田、草地和人工林（13、18和25年华北落叶松（Larix principis-rupprechtii））土壤活性有机碳含量及分配比例的差异。结果表明：农田和草地土壤活性有机碳含量比天然次生林分别低60%和36%,差异主要在0～70 cm土层;人工林比农田和草地分别高129%和29%,差异主要在0～50 cm土层。农田和草地土壤活性有机碳分配比例比天然次生林分别低11%和4%以上, 差异主要在0～20 cm与70～110 cm土层;人工林比农田和草地分别高13.3%和5.3%,差异主要在0～110 cm土层。土壤活性有机碳含量和分配比例随土层加深而递减,其中天然次生林和人工林土壤活性有机碳含量随土层加深而递减的幅度比农田和草地中大,农田土壤活性有机碳分配比例随土层加深而递减幅度较大。不同土地利用方式间土壤活性有机碳含量的差异比活性有机碳分配比例的差异大,土壤活性有机碳含量随土层加深而递减的幅度比分配比例随土层加深而递减的幅度大。这可能由土壤有机碳的输入、稳定性、质量和根系分布等差异所致。结果说明土壤活性有机碳含量和分配比例随天然次生林变成农田或草地而降低,随农田或草地中造林而增加,且土壤活性有机碳含量的变化幅度比分配比例大。另外,土壤活性有机碳含量和分配比例在土壤剖面的分布也随土地利用变化而改变,其中活性有机碳含量的变化幅度比分配比例大。     

Potential role of soil properties in the spread of CWD in western Canada

Chronic wasting disease (CWD) is a horizontally transmissible prion disease of free ranging deer, elk and moose. Recent experimental transmission studies indicate caribou are also susceptible to the disease. CWD is present in southeast Alberta and southern Saskatchewan. This CWD-endemic region is expanding, threatening Manitoba and areas of northern Alberta and Saskatchewan, home to caribou. Soil can serve as a stable reservoir for infectious prion proteins; prions bound to soil particles remain infectious in the soils for many years. Soils of western Canada are very diverse and the ability of CWD prions to bind different soils and the impact of this interaction on infectivity is not known. In general, clay-rich soils may bind prions avidly and enhance their infectivity comparable to pure clay mineral montmorillonite. Organic components of soils are also diverse and not well characterized, yet can impact prion-soil interaction. Other important contributing factors include soil pH, composition of soil solution and amount of metals (metal oxides). In this review, properties of soils of the CWD-endemic region in western Canada with its surrounding terrestrial environment are described and used to predict bioavailability and, thus, potential spread of CWD. The major soils in the CWD-endemic region of Alberta and Saskatchewan are Chernozems, present in 60% of the total area; they are generally similar in texture, clay mineralogy and soil organic matter content, and can be characterized as clay loamy, montmorillonite (smectite) soils with 6–10% organic carbon. The greatest risk of CWD spread in western Canada relates to clay loamy, montmorillonite soils with humus horizon. Such soils are predominant in the southern region of Alberta, Saskatchewan and Manitoba, but are less common in northern regions of the provinces where quartz-illite sandy soils with low amount of humus prevail.     

内蒙古草原草场放牧退化模式研究及退化监测专家系统雏议

本文将定位研究与路线考察相结合,将放牧影响下草原的动态演替及其在牧压梯度上的空间变化相对比,研究了内蒙古主要草原草场的放牧退化模式,并在此基础上初步探讨了判别草场退化的数量指标和退化监测专家系统。1)植物种与牧压关系的分析,区别出放牧的定性和定量指示植物及宜中牧植物,并划分植物为不同的放牧生态种组。2)退化草原恢复过程的研究表明,根茎禾草的恢复快于丛生禾草;群落恢复过程是单稳态的,且恢复演替动态与其牧压梯度上的空间变化相对应。3)内蒙古高原主要草原草场在持续放牧影响下均趋同于冷蒿(Artemisia frigida)草原。冷蒿是最可靠的正定量放牧指示植物,但同时又是优良牧草和草原退化的阻击者。4)讨论了草原草场退化的概念,论述了草原逆向演替与草场退化的区别和联系,提出了区分草原的逆向演替为草场熟化和退化两个过程,并依草场群落与牧压的关系建立了判定草场是否退化及退化程度的数量指标。5)初步设计了草原草场退化监测—决策专家系统,包括监测、判别和决策三个步骤。     

基于牧户感知和野外调查相结合的内蒙古东部草甸草原健康评价

治理草原退化是我国草原管理的重点和难点。我国目前关于草原退化判断、退化程度、原因及治理等系列问题的确定几乎皆以科学研究结果为依据,而忽视了牧户作为草原直接使用者和管理者的重要性。牧户对草原有自己的判断和认知,其与科学方法研究之间的矛盾已经影响到草原生态保护政策的有效实施。以内蒙古东部草甸草原牧户尺度草原为研究对象,借助牧户调研和野外调查相结合的方法,将牧户划分为高、中、低3个经济水平,并运用Condition-Vigor-Organization-Resilience (CVOR)指数评价法,分析评价草原生态系统健康状况。研究结果显示,牧户对草原健康状况的感知主要从植被、土壤、牲畜等方面,与科学方法评价指标选取具有相似性;牧户感知和CVOR指数法评价结果具有一致性,均判定草原生态系统呈现不同程度退化;统计检验显示牧户对植被、土壤、牲畜影响等指标变化感知方面均不存在显著差异(P0.05),CVOR指数法下不同经济水平牧户草场健康指数之间亦无显著差异(P0.05),两种方法均显示不同经济水平牧户草场退化程度无显著差异(P0.05)。研究证实了牧户感知在指标选取、评价结果方面具备用于准确评价草原健康状况的可行性和可信度。两种方法相互补充,将有利于更加准确、实时动态监测和评价牧户尺度草原生态健康状况,为调整优化畜牧业生产实践提供指导和草原生态保护和建设政策的有效实施提供保障。     

Microbial oxidation of elemental sulphur in brown soil

Plant and Soil - Brown soil formed from loamy clay was examined for its ability to produce sulphate from added elemental suphur. At higher rates of sulphur applications the pH of a slightly acid...