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1.
Impact of grassland contract policy on soil organic carbon losses from alpine grassland on the Qinghai–Tibetan Plateau 
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下载免费PDF全文 J. Cao Y. Gong E. T. Yeh N. M. Holden J. F. Adamowski R. C. Deo M. Liu J. Zhou J. Zhang W. Zhang S. Zhang D. Sheng S. Yang X. Xu M. Li Q. Feng 《Soil Use and Management》2017,33(4):663-671
Carbon storage in the soils on the Qinghai–Tibetan Plateau plays a very important role in the global carbon budget. In the 1990s, a policy of contracting collective grasslands to smaller units was implemented, resulting in a change from the traditional collective grassland management to two new management patterns: a multi‐household management pattern (MMP: grassland shared by several households without enclosures) and a single‐household management pattern (SMP: grassland enclosed and used by only one household). In 2016, 50 MMP and 54 SMP winter pastures on the Qinghai–Tibetan Plateau were sampled to assess the differences in soil organic carbon (SOC) between the two management patterns. Results showed that average SOC was significantly greater under MMP than under SMP, with an estimated 0.41 Mg C/ha/yr lost due to SMP following the new grassland contract. Based on the government's grassland policy, four grassland utilization scenarios were developed for both summer and winter pastures. We found that if the grassland were managed under SMP, likely C losses ranged between 0.31 × 107 and 6.15 × 107 Mg C/yr across the Qinghai–Tibetan Plateau relative to MMP, which more closely resembles pre‐1990s grassland management. Previous estimates of C losses have only considered land use change (with cover change) and ignored the impacts driven by land management pattern changes (without cover change). The new data suggest that C losses from the Qinghai–Tibetan Plateau are greater than previously estimated, and therefore that the grassland contract policy should be reviewed and SMP households should be encouraged to reunite into the MMP. These findings have potential implications for land management strategies not only on the Qinghai–Tibetan Plateau but also other grazing regions globally where such practices may exist. 相似文献
2.
采用野外调查和室内分析的方法,研究了河南鸡公山国家级自然保护区内森林风景区土壤理化特征对不同旅游干扰强度和干扰距离的响应。结果表明,重度干扰的土壤容重(1.23 g·cm-3)显著高于轻度(1.03 g·cm-3)和中度(1.07 g·cm-3)干扰的(P<0.05),而其土壤总孔隙度(57.5%)则显著低于轻度(61.3%)和中度(59.6%)干扰的(P<0.05);中度及重度干扰下的土壤全氮含量(1.9 g·kg-1和1.8 g·kg-1)和有机碳含量(19.3 g·kg-1和21.2g·kg-1)均显著低于轻度干扰的(2.2 g·kg-1和26.8 g·kg-1)。与背景区(距干扰中心区边缘外10 m以上)相比,干扰导致缓冲区(距干扰中心区边缘外3~10 m)的土壤容重和总孔隙度变化随着干扰强度的增加而下降,而核心区(位于干扰中心区0~1 m)的土壤容重和总孔隙度的变化随干扰强度的增加而增加。以上研究结果可为森林风景区的规划和科学管理提供参考。 相似文献
3.
Switches are processes in which there is positive feedback between vegetation and environment. Landscape features can be created and modified by switches. The concept has previously been used with physical factors and non-human animals as the switch mediator, i.e. the factor which the vegetation modifies and which in turn affects the vegetation. Here, the switch concept is extended to include some types of human behaviour as possible switch mediators. With this extension, the switch concept can explain the impact on the landscape of some types of human behaviour. Examples are given of the behaviour of mower drivers, mowing up to a boundary which they create and/or maintain, and of walkers trampling tracks which they create and/or maintain. Other possibilities are discussed briefly. It is concluded that the concept of a human-mediated switch can unify the study of human behaviour, vegetation processes and landscape ecology. 相似文献
4.
本试验采用人工践踏的方式,研究了不同组合配比的基质对无土草坪耐践踏性的影响。结果表明,良好的无土草坪基质配比及适合的厚度是保证无土草坪优良的耐践踏性及观赏性的关键。本试验中,草坪草生长基质层和弹性材料层均为25 mm,结构合理、厚度适中,克服了现有草坪基质薄、持水力差的缺点。在相同践踏强度下,能维持较高水平的草层高度、草坪盖度和草坪草分蘖数,分别达到了5.14 cm、97.60%和123.97 个·dm-2,且停止践踏后草坪质量能快速恢复。均匀混合的草坪草生长基质层和弹性材料层,在厚度一致的前提下并不耐践踏,实际效果不好。土壤坪床的处理效果最差。因此,具有独立的草坪草生长基质层和弹性材料层且厚度适中的基质,适用于生产耐践踏性好的无土草坪。 相似文献
5.
践踏强度对不同坪床结构狗牙根地上部生长的影响 总被引：3，自引：0，他引：3
在6种沙基结构坪床上建植狗牙根草坪,用特制践踏器进行4种强度的践踏处理。结果表明:轻度践踏对草坪草高度、盖度和密度的影响较小;中度和重度践踏对草坪会造成较大损伤,草坪的叶片长度和干重急剧下降,盖度和密度严重减少。不同坪床结构中,表土铺沙厚度为20~25 cm处理的草坪草植株生长较差;全土处理的草坪草,在不践踏时,生长较好,但是在践踏胁迫下,植株的干重、密度和盖度的变化幅度均较大;土表铺沙厚度为5~15 cm处理的草坪草在不践踏时生长较好,在践踏胁迫下,各指标的变化幅度较小。 相似文献
6.
为了揭示喀斯特林下经济活动中人为踩踏对土壤入渗特性的影响规律,以喀斯特山地森林内部(未受干扰区域)、森林小径中央、森林小径边缘和裸地为试验样地,基于盘式入渗试验测定不同负压水头下(-0.5,-3,-6,-9 cm)的非饱和导水率(K_9、K_6、K_3、K_(0.5))、饱和导水率K_S、Gardner α常数和水流贡献率。通过原位染色示踪试验分别估算各样地的剖面染色面积比(DC)、均匀渗透深度(UniFr)和优先流百分比(PF-fr),分析了人为踩踏对喀斯特森林土壤优先流特征的影响。结果表明,森林小径中央的K_S(45.800×10~(-3) cm/min)比森林内部(101.000×10~(-3) cm/min)降低55%,Gardner α常数和土体孔隙数量的剧烈减少阐明森林路径中土壤入渗能力减弱的原因;森林小径中央的优先流百分比(71.955%)显著高于森林内部(36.734%),表示人为踩踏活动增强了土壤优先流强度;4种人为踩踏干扰程度下土壤的大孔隙平均水流贡献率均超过95%,喀斯特山地森林土壤水分入渗以大孔隙为主要入渗通道。森林植被覆盖能够有效提升土壤入渗能力和抑制土壤优先流,研究结果为喀斯特林下经济开发过程中的负面清单建立提供了试验依据。 相似文献
7.
Marion Kissling K. Tessa Hegetschweiler Hans-Peter Rusterholz Bruno Baur 《Applied soil ecology》2009,42(3):303-314
Understanding the effects of disturbance by human trampling on ecosystem processes is essential for the management of recreational areas. Discussions on recreational impacts are based either on data from trampling experiments or on field survey data from sites subjected to long-term recreational use, but rarely on a combination of both. We examined whether results from a short-term trampling experiment reflect the impact of long-term trampling around frequently used fire places. We compared short- and long-term effects of human trampling on above-ground forest vegetation and soil physical, chemical and microbial characteristics. We found both similarities and differences in short- and long-term trampling effects. Both short- and long-term trampling reduced plant cover, plant height and species density, though long-term effects were more pronounced than short-term effects. In both approaches, leaf litter biomass decreased, whereas soil density increased with trampling intensity. Other soil characteristics including soil moisture, total soil organic matter content and total organic nitrogen content were not or only marginally affected by short- and long-term trampling. Furthermore, soil microbial biomass and the activity of dehydrogenase did not change in both approaches. In contrast, the activity of β-glucosidase was only reduced by short-term trampling, whereas activity of phosphomonoesterase was reduced only by long-term trampling. Soil compaction was one factor reducing microbial activities at low and medium trampling intensities in our experiment and in the highly compacted area around the fire rings. We conclude that it could be problematic to use the results of short-term trampling experiments to predict general long-term trampling effects. Our results imply also that the restoration of degraded sites might be hampered by the low nutrient turnover resulting from the reduced litter layer and changes in enzyme activities, mitigating a successful re-establishment and growth of plants. 相似文献
8.
为探明高寒草甸土壤对家畜践踏的响应机制,于甘肃天祝进行了牦牛和藏羊的模拟践踏试验,研究了不同强度模拟践踏对土壤物理特性及微生物数量的影响。结果表明,0～10 cm土层的土壤紧实度和容重,随着践踏强度的增加均呈递增趋势;而呼吸速率和饱和导水率呈递减趋势。0～10 cm土层的3大微生物数量随践踏强度的增大而减小。同一践踏强度下,牦牛践踏后0~10 cm土层的土壤紧实度和容重均大于藏羊践踏处理;而饱和导水率、呼吸速率和微生物数量均小于藏羊践踏处理。综合分析认为,家畜的践踏强度越大,土壤的压实效应越显著;一个生长季的模拟践踏主要影响0～10 cm土层土壤的物理性质;且牦牛对土壤的压实效应和对微生物分布的抑制作用均大于藏羊。 相似文献
9.
We evaluated the potential of tree-ring techniques for the reconstruction of recent and past seasonal activity of introduced white-tailed deer in a boreal environment of eastern Canada. Hoof scrape scars on balsam fir stems and trampling scars on roots were used to reconstruct deer activity during the winter and snow-free seasons, respectively. Tree damage showed that there was continuous deer activity in the north-central part of Anticosti Island since the mid-1960s. High scrape scars along tree stems (3–3.5 m from the ground) indicate that 1975, 1976, 1981, 1983 and 1985 were years of intensive food search by deer on high balsam fir foliage. The annual number of hoof scrape scars was low between 1982 and 1985, when severe defoliation by the spruce budworm, combined with deer browsing, led to high fir sapling mortality, food depletion, degradation of the winter shelter forests and a decrease in deer activity. The lowest scrape scars 50 cm above ground correspond to the mean height of the residual snowpack in the shelter forest at springtime, when deer start searching for food in nearby open sites and use logging roads, where dead and bonsai-like fir predominate due to overbrowsing. The trampling scar age frequency distribution from two sites indicated that deer activity during the snow-free season started synchronously in the late 1960s. In response to degradation of winter shelter forests, deer may have moved from the southern part to the north-central part of the island and other sectors to survive. Deer-induced tree damage and tree-ring techniques can thus be used to reconstruct past seasonal activity of white-tailed deer. 相似文献
10.
Csaba Centeri Edina Herczeg Márton Vona Katalin Balázs Károly Penksza 《植物养料与土壤学杂志》2009,172(4):586-592
Vegetation of the Tihany Peninsula in Hungary has undergone serious changes caused by heavy trampling and overgrazing during the last century. In Tihany, the vegetation started to change towards anthropogenic associations. After grazing ceased, vegetation started to rearrange. There were no significant changes in species composition on trampled areas (on the ridge of the hill) between the examinations in 1994 and 2002. As a result of ceased grazing, the proportion of natural species was high in the grasslands of the S Nyereg Hill in 1994, while during the 2002 investigations, forest and scrub expanded at a rate that did not leave space for grassland on shallow soils and slope steppe (closing dry grasslands on hilly areas). The coverage of Elymus repens decreased, while Festuca species increased. The possible effects of plant‐cover change on soil loss were examined with the USLE (Universal Soil Loss Equation) model on the sloping areas. Eliminating harmful effects can decrease soil degradation, but the original state of soils can be restored only after a long period (hundreds of years). Further degradation of soils assists the expansion of drought‐resistant species and weeds in the associations. In 2007, soil‐thickness measurements and on‐site examinations were carried out to check the results of the former surveys and modeling. 相似文献