鼠荒地植被恢复技术试验研究

通过采用灭鼠、灭鼠+围栏封育、灭鼠+围栏封育+补播等培育技术措施对天然草原高原鼢鼠危害形成的鼠荒地进行了植被恢复试验研究。结果表明,对鼠荒地土丘采取灭鼠、灭鼠+围栏封育、灭鼠+围栏封育+补播等培育技术措施,均可明显提高植被盖度、高度和产草量,其中以灭鼠+围栏封育+补播效果最好。在补播牧草品种中以补播无芒雀麦效果最好,其次是补播垂穗披碱草。     

Vegetation Responses to Pinyon–Juniper Treatments in Eastern Nevada

Comparisons of tree-removal treatments to reduce the cover of single-leaf pinyon (Pinus monophylla Torr. and Frém.) and Utah juniper (Juniperus osteosperma [Torr.] Little), and subsequently increase native herbaceous cover in black sagebrush (Artemisia nova A. Nelson), are needed to identify most cost-effective methods. Two adjacent vegetation management experiments were initiated in 2006 and monitored until 2010 in eastern Nevada to compare the costs and efficacy of various tree reduction methods. One Department of Energy (DOE) experiment compared a control to five treatments: bulldozing imitating chaining ($205 · ha^-1), lop-pile-burn ($2 309 · ha^-1), lop-and-scatter ($1 297 · ha^-1), feller-buncher and chipper ($4 940 · ha^-1), and mastication ($1 136 · ha^-1), whereas a second Bureau of Land Management (BLM) experiment compared one-way chaining ($205 · ha^-1) to a control treatment. Chaining and bulldozing resulted in the least reduction of tree cover among the treatments. In the DOE experiment, forb cover only decreased in the mastication treatment. Litter increased in all methods. Slash cover was lowest in the control and lop-pile-burn treatments, intermediate in the feller-buncher and mastication treatments, and highest in the bulldozing and lop-and-scatter treatments. By 2010, forb cover and the combined cover of dead shrubs and trees were increased and decreased, respectively, by chaining in the BLM experiment. Nonnative annual grass and biotic crust were absent or uncommon before and after treatment implementation. In both experiments, tree removal resulted in a nonsignificant increase in perennial grass cover even 4 yr post-treatment. An ecological return-on-investment (EROI) metric was developed to compare perennial grass cover and tree cover per unit area cost of each active treatment. By 2010, chaining or bulldozing, followed by mastication, showed the highest EROI for improving perennial grass and decreasing tree cover. Mastication is recommended for restoration of smaller tree-encroached areas, whereas land managers should reconsider smooth chaining, despite its negative perceptions, for rapid and cost-efficient restoration of large landscapes obligates.     

Vegetation Production Responses to October Grazing in the Nebraska Sandhills

Understanding the long-term effect of summer grazing date and fall stocking rate on herbage production is critical to extending the grazing season in the Nebraska Sandhills. A study was conducted from 1997 to 2002 at the Gudmundsen Sandhills Laboratory located near Whitman, Nebraska, to determine the herbage production response to summer grazing date and October stocking rate on two different sites. Site 1 was dominated by warm-season grasses and site 2 was dominated by cool-season graminoids. At each site, three 0.37-ha pastures were constructed in each of four blocks before application of summer grazing treatments. Pastures in each block were grazed at 0.5 animal-unit months (AUM) · ha^?1 in June or July, or were deferred from summer grazing. Following summer grazing treatments, October stocking rate treatments (no grazing or 1.0, 2.0, or 3.0 AUM · ha^?1) were applied to subunits of each summer grazing date pasture during mid-October. Vegetation was sampled in each pasture in mid-June and mid-August and sorted by functional group to determine the effect of 5 yr of grazing treatments on herbage production and residual herbage. Herbage production was not affected by summer or October grazing treatments on the warm-season grass–dominated site. Increasing October stocking rate, however, reduced cool-season graminoid production and subsequent herbage production 25% by year 5 of the study. Residual herbage at both sites at the end of the October grazing periods explained as much as 16% to 34% of subsequent year’s herbage production. Grazing managers in the Nebraska Sandhills can extend the grazing season by lightly stocking pastures in the summer to facilitate additional fall grazing. Heavy stocking in October over several years on cool-season–, but not warm-season–, dominated sites will reduce production of cool-season graminoids on these sites.     

Vegetation Responses to Prescribed Burning of Grazed Shortgrass Steppe

Over the past century, fire has been widely suppressed in the western Great Plains, in part because of the potential negative effects on forage production for livestock. More recently, interest in the use of prescribed fire in shortgrass steppe has increased because of the potential applications for wildlife management, control of unpalatable plant species, and restoration of historic disturbance regimes. We studied the effects of prescribed burns conducted during late winter on herbaceous production, forage nitrogen content, and plant species composition of shortgrass steppe on the Pawnee National Grassland in northeastern Colorado. Late-winter burns conducted in moderately grazed sites under a wide range of precipitation conditions during 1997–2001 did not negatively affect herbaceous production in either the first or the second postburn growing season. Burning followed by a severe drought in 2002 reduced production by 19% in the second postburn growing season of 2003. Burns temporarily suppressed the abundance of broom snakeweed (Gutierrezia sarothrae) and prickly pear cactus (Opuntia polyacantha) and enhanced forage nitrogen content during May and June of the first postburn growing season. These findings suggest that, except following severe drought, prescribed burns conducted during late winter in grazed shortgrass steppe for objectives unrelated to livestock production can also have neutral or positive consequences for livestock.     

Applying Public Participation Geographic Information Systems to Wildlife Management

Wildlife management increasingly incorporates public participation to be more inclusive and reduce tensions between management and the general public in the decision-making process. There is also a need, however, to include spatial data since most wildlife biological and biophysical data are stored spatially in geographic information systems (GIS). This article presents a method for integrating this information using public participation geographic information systems (PPGIS). We asked stakeholders to identify specific places on a map that they would like to see maintained for the conservation of particular threatened species. This information is useful for identifying public wildlife management preferences and for allowing comparisons between public and expert opinions. We found high levels of public accuracy in identifying suitable habitat for threatened species conservation. We also identified places of potential conflict due to incompatible stakeholder preferences, but found little conflict between public conservation and development preferences.     

藏北高寒草地土壤真菌群落系统发育多样性对放牧的响应

本研究依托沿海拔梯度布设的三个配对的围栏和自由放牧样地探讨了土壤真菌系统发育多样性对放牧的响应规律.结果表明:暖季放牧和冷季放牧都没有改变高寒草原化草甸土壤真菌系统发育α多样性,暖季放牧也没有改变高寒草甸土壤真菌系统发育α多样性;暖季放牧和冷季放牧都显著改变了高寒草原化草甸土壤真菌群落系统发育结构,且暖季放牧也显著改变...     

野生动物饲养管理体系与认证研究

野生动物饲养管理体系是野生动物生产经营组织围绕野生动物饲养而展开的计划、组织、指挥、协调和控制活动的管理体系,通常包括制定饲养方针和目标,开展饲养策划、饲养控制、饲养保证和饲养改进活动,覆盖范围包括法律法规和相关要求、动物福利、环境和职业健康安全。建立全面、协调、可持续的野生动物饲养管理体系,是制度创新和管理创新,是实现资源可持续利用,组织可持续发展的必然要求,也是野生动物行政管理的根本期望。实施野生动物饲养管理体系能降低经营风险,提高管理水平,保障动物福利,保护员工权益。开展野生动物饲养管理体系认证,借助社会力量监督和管理野生动物饲养业,逐步用认证替代现行的政府行政性监管方式,是转变政府职能,提高行政效率,降低行政成本,减少行政责任和风险的一条重要途径。     

毛乌素荒漠草原植被特征对降水变化的响应

荒漠草原植被特征对降水变化敏感,研究降水变化对荒漠草原植被特征影响具有重要的生态学意义.本研究以宁夏盐池县典型荒漠草原(毛乌素沙区农牧交错带)为研究对象,利用遮雨棚技术模拟正常降水的33％,66％,100％,133％ 和166％,在降水变化处理2年后,探讨荒漠草原植被特征对降水变化的响应规律.结果表明,增加降水使群落中...     

西北地区野生动植物进出口管理初探

西北地区(陕、甘、宁、青四省区)野生动植物资源十分丰富,近年来随着改革开放的深入及西部大开发的实施,野生动植物进出口贸易发展迅速;贸易产品由最初以野禽野味、动物皮毛为主向观赏野生动物、中药材、生物提取物、木材、科研样品等商品种类转变,成为该地区重要的创汇来源。为处理好资源保护、履行国际义务和发展经济之间的矛盾,本文拟就野生动植物进出口贸易管理方面提出建议。     

A Comparison of Satellite-Derived Vegetation Indices for Approximating Gross Primary Productivity of Grasslands

Gross primary productivity (GPP) is a key component of ecosystem carbon fluxes and the carbon balance between the biosphere and the atmosphere. Accurate estimation of GPP is essential for quantifying plant production and carbon balance for grasslands. Satellite-derived vegetation indices (VIs) are often used to approximate GPP. The widely used VIs include atmospherically resistant vegetation index, enhanced vegetation index (EVI), normalized difference greenness index, normalized difference vegetation index, reduced simple ratio, ratio vegetation index, and soil-adjusted vegetation index (SAVI). The evaluation of the performance of these VIs for approximating GPP, however, has been limited to one or two VIs and/or using GPP observations from one or two sites. In this study, we examined the relationships between the nine VIs derived from the moderate resolution imaging spectroradiometer (MODIS) and tower-based GPP at five eddy covariance flux sites over the grasslands of northern China. Our results showed that the nine VIs were generally good predictors of GPP for grasslands of northern China. Overall, EVI was the best predictor. The correlation between EVI and GPP also declined from the south to the north, indicating that EVI and GPP exhibited closer relationships in more southerly sites with higher vegetation cover. We also examined the seasonal influence on the correlation between VIs and GPP. SAVI exhibited the best correlation with GPP in spring when the grassland canopy was sparse, while EVI exhibited the best correlation with GPP in summer when the grassland cover was dense. Our results also showed that VIs could capture variations in observed GPP better in drought period than in nondrought period for an alpine meadow site because of the suppression of vegetation growth by drought.     

Woody Vegetation Persistence and Disturbance in Central Texas Grasslands Inferred From Multidecadal Historical Aerial Photographs

Woody vegetation encroachment has been assumed to occur uniformly over the past century across the southern Great Plains of the United States. To assess this assumption, we evaluated changes in pixels classified as woody vegetation from aerial photographs from 1937 to 2004 that were acquired approximately every 13 yr for a 7 109-ha wildlife refuge located in the eastern Edwards Plateau region of central Texas. We found that the percentage of total area classified as woody vegetation changed minimally (62.0–64.2%) from 1937 to 2004. However, on average, 32% of the study area changed classification between woody vegetation and nonwoody vegetation pixels between each photograph date. To assess potential causes of woody vegetation change, we analyzed contiguous pixels with area ≤ 1 ha and area > 1 ha representing small- and large-scale disturbances, respectively. Small-scale woody vegetation pixel loss was found to be moderately low, ranging between 11.1% and 12.6% of the study area for the period of analysis, indicating relatively constant levels of canopy-level disturbance. Large-scale woody vegetation pixel loss peaked in the 1951–1964 time interval, where we identified 98 patches averaging 8.1 ha and covering 7.6% of the study area. The timing and area of these potential disturbances were correlated with drought and increased fire frequency within our study area. This methodology, which includes careful georectification and radiometric standardization of the historical photographs, can be used to detect interdecadal variability related to changes in types of disturbance over longer periods of time. This study also shows that repeated observations, such as those from aerial photographs, may be required to adequately characterize woody plant encroachment, particularly in subhumid grasslands, where disturbance and regrowth of woody plants may occur at decade time scales.     

内蒙古典型草地不同时期土壤及植被养分评价

[目的]研究内蒙古典型草地不同时期土壤及植被营养状况的差异及变化特点,为内蒙古典型草地的合理利用、退化草地的恢复治理以及畜牧业的可持续发展提供参考。[方法]从内蒙古不同地区典型草原选取8个监测点,包括G1（鄂温克草原,温性草甸草原,呼伦贝尔市）、G2（乌拉特草原,荒漠草原,巴彦淖尔市）、G3（天然草滩,乌兰察布市）、G4（辉腾锡勒草原,五花草甸草原,乌兰察布市）、G5（科尔沁草原,温性草甸草原,通辽市）、G6（人工牧草种植地,赤峰市）、G7（乌拉特草原,荒漠草原,包头市）、G8（格根塔拉草原,荒漠草原,乌兰察布市）;于2020年牧草返青期、旺盛期、枯萎期分别从不同监测点样方中取0~20 cm土层土样及植物样品地上部分,测定土壤和植物中的常规养分含量;利用主成分分析法计算不同监测点不同时期土壤及植被营养水平的综合得分并排序。[结果]返青期、旺盛期、枯萎期土壤全氮含量均为G4监测点（辉腾锡勒草原）最高,极显著（P<0.01）高于其他监测点;旺盛期、枯萎期G7监测点（包头市境内乌拉特草原）最低。3个时期土壤有效磷含量均为G6监测点（人工牧草种植地）最高,显著（P<0.05）或极显著（P<0.01）高于其他监测点。3个时期土壤有机质含量均为G4监测点（辉腾锡勒草原）最高,极显著（P<0.01）高于其他监测点,G7监测点（包头市境内乌拉特草原）最低。返青期G6监测点（人工牧草种植地）的植被氮、磷、钾含量均为最高,极显著（P<0.01）高于其他监测点。旺盛期G8监测点（格根塔拉草原）的植被氮、钾含量最高,G6监测点（人工牧草种植地）的植被磷含量最高。枯萎期G3监测点（乌兰察布市境内天然草滩）的植被氮、磷含量最高,G4监测点（辉腾锡勒草原）的植被钾含量最高。3个时期植被粗纤维含量均是G5监测点（科尔沁草原）最高,G4监测点（辉腾锡勒草原）最低。土壤营养状况评分为：G4监测点（辉腾锡勒草原）3个时期评分均较高,G7监测点（包头市境内乌拉特草原）3个时期评分均最低;植被营养状况评分为：G2监测点（巴彦淖尔市境内乌拉特草原）及G6监测点（人工牧草种植地）返青期>旺盛期>枯萎期,其余监测点均是旺盛期>返青期>枯萎期。[结论]内蒙古典型草原的土壤及植被养分含量存在明显的时空差异。总体来看,草甸草原返青期、旺盛期、枯萎期土壤中养分综合评分较高,荒漠草原3个时期评分较低;不同草原类型的植被养分综合评分在旺盛期较高,枯萎期较低。     

通天河流域植被动态监测及其对气候因子的响应

通天河是长江源头重要的干流,探讨其植被生长状况及其与气候因子的响应对三江源区生态系统稳定性研究具有重要意义。本文以通天河流域为研究区,采用了广义回归神经网络(General regression neural network, GRNN)计算模型来反演叶面积指数(Leaf area index, LAI)和植被覆盖度(Fractional vegetation cover, FVC)数据,分析LAI和FVC的变化特征及其对气候因子的响应。分析结果表明：通天河流域植被总体呈显著波动增长趋势,LAI,FVC增长速率分别为(1.2×10^-3)·a^-1和(0.9×10^-3)·a^-1;流域内植被明显改善区分布在海拔较低水热条件较好的沟谷地带,但下游人类活动频繁的曲麻莱县和治多县周边地区植被退化明显;流域内植被主要生长在海拔4 000 m以上地区,超过5 200 m植被生长差,覆盖类型以低覆盖为主,中-高覆盖集中在河流下游地区;相较于气温而言,降水是影响该流域植被的主导因素,与植被LAI和FVC呈显著正相关。     

几种冷季型草坪草苗期对二氯喹啉酸的耐药性试验

就几种冷季型草坪草在不同苗龄对二氯喹啉酸的抗性研究结果表明:二氯喹啉酸在高羊茅和多年生黑麦草两种草坪中的安全用药时期为播种后任何时间,在草地早熟禾中的安全用药时期为播种14d后,即幼苗2～3叶期以后;在安全期初期用药,药量不超过0.60kg/hm2(50%可湿性粉剂),随着施药期的延后,安全剂量有所增加。     

东祁连山高寒草甸植被特征和生物多样性对生境的响应

为了探究海拔和坡向演变过程中高寒草甸植被的变化特征,本试验以东祁连山的高寒草甸为研究对象,采用相关性和聚类分析等方法,研究了不同海拔(2800m,3000m,3200m,3400m,3600m,3800m和4000m)和坡向(阳坡、阴坡)的植被特征、功能群组成和多样性指数的变化规律.结果表明:随着海拔升高,植被盖度、草...     

Vegetation Responses to Fixed Stocking Densities in Highly Variable Montane Pastures in the Chinese Altay

Variability in aboveground herbaceous biomass and its quality were studied in response to three different stocking densities during a 2-yr grazing experiment with sheep on a montane summer pasture in the Chinese Altay. We determined herbaceous cover and aboveground biomass in 16 paddocks of 0.25 ha each. Vegetation cover showed high spatial variation, prompting us to implement a randomized block design. Forage intake of one male sheep per paddock was quantified four times per grazing season by collection of total feces and estimation of diet digestibility. Sheep weight was recorded every 3 wk. Aboveground herbaceous dry mass (DM) was characterized by pronounced annual variation. Biomass quality declined with progressing season and increasing sheep density. Daily organic matter intake per sheep ranged from 0.7 to 1.4 kg, which was paralleled by a biomass removal of 710 ? 1 560 kg DM/ha at densities of 8 ? 24 sheep/ha. At 8 sheep/ha, animals gained weight throughout each grazing period, whereas weight losses of 40 ? 100 g/d occurred at higher densities. These results challenge the presently followed concept of a fixed stocking density for summer pastures in Altay Prefecture, Xinjian, China. Such practice may result in low herbage allowances and thus deficient sheep nutrition in one year, as well as underutilization of forage resources in another. Flexible adjustment of stocking densities is also advisable for montane pastures where spatiotemporal variability, although less pronounced than in desert steppes of the Altay foothills, is nonetheless highly relevant.