共查询到20条相似文献,搜索用时 15 毫秒
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河南省天然草地野生牧草资源的研究 总被引:5,自引:1,他引:4
河南省天然草地有野生牧草1405种,其中主要饲用牧草有340种,它们生产性能,经济性状良好,并构成复杂多样的草地植被,具有较高的开发和利用价值。 相似文献
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天然草地改良效果的研究 总被引:3,自引:0,他引:3
羊草草原是北方的典型草原,为呼伦贝尔牧业提供优良饲草,但由于各种经济利益的驱使和自然条件的恶化,海拉尔草地的情况不断恶化,退化现象严重。退化草地靠自然恢复往往是缓慢的,甚至会加剧逆向演替,因此,对退化草地加以改良是十分必要的。 相似文献
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Samuel D. Fuhlendorf David M. Engle R. Dwayne Elmore Ryan F. Limb Terrence G. Bidwell 《Strength and Conditioning Journal》2012,65(6):579-589
This article examines the question of how well the rangeland management profession has served conservation of patterns and processes that support multiple ecosystem services. We examine the paradigms under which rangeland management operates and argue that our profession developed under the utilitarian paradigm with the primary goals of sustainable forage for livestock production. While optimization of multiple rangeland products and services has always been a consideration, a comprehensive set of principles have not be been developed to advance this concept. We argue that fire and grazing, often viewed as mere tools used for production goals, should rather be viewed as essential ecosystem processes. Rangeland management continues to operate under the utilitarian paradigm appropriate to societal values of the 20th century and by and large has failed to provide management guidance to reverse degradation of several highly valued ecosystem services. We support this argument with evidence that biodiversity has declined on rangelands in the past half century and that much of this decline is due to management goals that favor a narrow suite of species. The full suite of ecosystem services valued by society will only benefit by management for heterogeneity, which implies that there is no one goal for management and that landscape-level planning is crucial. Explicitly incorporating heterogeneity into state-and-transition models is an important advancement not yet achieved by our profession. We present new principles for rangeland management formed on the basis of conservation of pattern and process. While recognizing that many rangelands have significant deviations from historic plant communities and disturbance regimes, we suggest that management for conservation of pattern and process should focus on fire and grazing to the extent possible to promote a shifting mosaic across large landscapes that include patches that are highly variable in the amount of disturbance rather than the current goal of uniform moderate disturbance. 相似文献
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从天然牧地看 ,青藏大区具有高蛋白、高脂肪、高无氮浸出物、高灰分、高代谢能及低纤维 (即 5高 1低 )的特征 ;南方大区恰好相反 ,呈现为 5低 1高的特征 ;北方大区的各项营养成分含量居中。就人工牧地而言 ,粗蛋白含量亦为青藏大区较高 ,粗脂肪和粗灰分则以南方大区较高 ,而粗纤维、无氮浸出物和代谢能 3个大区相近。人工牧地与天然牧地比较 ,前者的粗蛋白、可消化蛋白、Ca和P的含量显著地高 ,营养比和粗脂肪明显地低 ,而 2类牧地的代谢能、粗纤维、无氮浸出物和粗灰分相近或略有差异。由此表明 ,人工牧地在营养价值方面优于天然牧地 ,原因主要在于其蛋白质含量较高、营养比较低。 相似文献
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David C. Goodrich D. Phillip Guertin I. Shea Burns Mark A. Nearing Jeffry J. Stone Haiyan Wei Philip Heilman Mariano Hernandez Ken Spaeth Fred Pierson Ginger B. Paige Scott N. Miller William G. Kepner George Ruyle Mitchel P. McClaran Mark Weltz Leonard Jolley 《Herpetological Monographs》2011,33(4):41-47
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Jason W. Karl Michael C. Duniway Sarah M. Nusser Jean D. Opsomer Robert S. Unnasch 《Strength and Conditioning Journal》2012,65(4):330-339
The availability of very-large-scale aerial (VLSA) imagery (typically less than 1 cm ground-sampling-distance spatial resolution) and techniques for processing those data into ecosystem indicators has opened the door for routinely using VLSA imagery in rangeland monitoring and assessment. However, for VLSA imagery to provide defensible information for managers, it is crucial to understand the statistical implications of designing and implementing VLSA image studies, including consideration of image scale, sample design limitations, and the need for validation of estimates. A significant advantage of VLSA imaging is that the researcher can specify the scale (i.e., spatial resolution and extent) of the images. VLSA image programs should plan for scales that match monitoring questions, size of landscape elements to be measured, and spatial heterogeneity of the environment. Failure to plan for scale may result in images that are not optimal for answering management questions. Probability-based sampling guards against bias and ensures that inferences can be made to the desired study area. Often collected along flight transects, VLSA imagery lends itself well to certain probability-based sample designs, such as systematic sampling, not often used in field studies. With VLSA image programs, the sample unit can be an entire image or a portion of an image. It is critical to define the sampling unit and understand the relationship between measurements and estimates made from the imagery. Finally, it is important to statistically validate estimates produced from VLSA images at selected locations using quantitative data of the same scale and more precise and accurate than the VLSA image techniques. The extent to which VLSA imagery will be useful as a tool for understanding the status and trend of rangelands depends as much on the ability to build the imagery into robust programs as it does on the ability to quickly and relatively easily collect VLSA images over large landscapes. 相似文献
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开垦草原、过度农垦和撂荒、过度利用水资源、超采地下水,导致干旱区土地沙化、沙尘源面积扩大;草原持续超载过牧,滥采滥挖草原的植物资源,无序开发草原矿产资源,人为破坏草原植被,造成草原沙化;超越水土资源承载力,追求高产出的不当农业经营方式,违反自然规律的生态建设,造就了新的沙尘源,助长了沙尘暴的暴发。通过采用资源可持续利用技术、降低草原和土地利用强度、恢复干旱草原以牧为主的经营方式等措施,可以提高植被覆盖度,减少裸露旱作农田、撂荒地等沙尘源面积,从而减少沙尘暴的暴发次数,减轻其危害程度。 相似文献
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《Strength and Conditioning Journal》2007,60(3):209-217
The growth of landscape-scale land management necessitates the development of methods for large-scale vegetation assessment. Field data collection and analysis methods used to assess ecological condition for the 47 165-h North Spring Valley watershed are presented. Vegetation cover data were collected in a stratified random design within 6 Great Basin vegetation types, and the probability of detecting change in native herbaceous cover was calculated using power analyses. Methods for using these quantitative assessment data are presented to calculate a departure index based on reference condition information from LANDFIRE (an interagency effort to map and model fire regimes and other biophysical characteristics at a mid-scale for the entire United States) Biophysical Setting models for the mountain big sagebrush (Artemisia tridentata Nutt. subsp. vaseyana [Rydb.] Beetle) vegetation type. For mountain big sagebrush in the North Spring Valley landscape, we found that the earliest successional classes were underrepresented and that mountain big sagebrush moderately invaded by conifers was more abundant than predicted by the LANDFIRE reference based on the historic range of variability. Classes that were most similar to the reference were mountain big sagebrush with the highest conifer cover and late development mountain big sagebrush with perennial grasses. Overall, results suggested that restoration or approximation of the historic fire regime is needed. This method provides a cost-effective procedure to assess important indicators, including native herbaceous cover, extent of woody encroachment, and ground cover. However, the method lacks the spatial information that would allow managers to comprehensively assess spatial patterns of vegetation condition across the mosaics that occur within each major vegetation type. The development of a method that integrates field measurements of key indicators with remotely sensed data is the next critical need for landscape-scale assessment. 相似文献
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Michael C. Duniway Jeffrey E. Herrick David A. Pyke Toledo P. David 《Strength and Conditioning Journal》2010,63(5):524-536
Linear disturbances associated with on- and off-road vehicle use on rangelands has increased dramatically throughout the world in recent decades. This increase is due to a variety of factors including increased availability of all-terrain vehicles, infrastructure development (oil, gas, renewable energy, and ex-urban), and recreational activities. In addition to the direct impacts of road development, the presence and use of roads may alter resilience of adjoining areas through indirect effects such as altered site hydrologic and eolian processes, invasive seed dispersal, and sediment transport. There are few standardized methods for assessing impacts of transportation-related land-use activities on soils and vegetation in arid and semi-arid rangelands. Interpreting Indicators of Rangeland Health (IIRH) is an internationally accepted qualitative assessment that is applied widely to rangelands. We tested the sensitivity of IIRH to impacts of roads, trails, and pipelines on adjacent lands by surveying plots at three distances from these linear disturbances. We performed tests at 16 randomly selected sites in each of three ecosystems (Northern High Plains, Colorado Plateau, and Chihuahuan Desert) for a total of 208 evaluation plots. We also evaluated the repeatability of IIRH when applied to road-related disturbance gradients. Finally, we tested extent of correlations between IIRH plot attribute departure classes and trends in a suite of quantitative indicators. Results indicated that the IIRH technique is sensitive to direct and indirect impacts of transportation activities with greater departure from reference condition near disturbances than far from disturbances. Trends in degradation of ecological processes detected with qualitative assessments were highly correlated with quantitative data. Qualitative and quantitative assessments employed in this study can be used to assess impacts of transportation features at the plot scale. Through integration with remote sensing technologies, these methods could also potentially be used to assess cumulative impacts of transportation networks at the landscape scale. 相似文献