不同海拔高度高寒草甸光能利用效率的遥感模拟

利用植被光合模型模拟了藏北高原3个海拔高度(4300,4500 m和4700 m)的高寒草甸生态系统的光能利用效率.海拔4500 m的光能利用效率均值(0.47 g C/MJ)显著高于海拔4300 m(0.38 g C/MJ)和4700 m(0.35 g C/MJ),而海拔4300 m和4700 m两者间差异不显著.相关分析和多重逐步回归分析表明,影响每个海拔光能利用效率季节变化的主要因子为空气温度,相对湿度以及地表水分指数,这3个因子共同解释了99％以上的光能利用效率的季节变化,其中空气温度的贡献最大,相对湿度的贡献次之,地表水分指数的贡献最小,这说明在3个海拔的任何一个海拔高度,温度对光能利用效率季节变化的胁迫作用大于水分对光能利用效率季节变化的胁迫作用.多重逐步线性回归分析表明,生长季节均土壤含水量是决定生长季节均光能利用效率沿海拔高度分布的主导因子.单因子线性回归分析表明,地表水分指数可以定量化高寒嵩草草甸生态系统水分状况,它同时可以反应土壤水分、近地表空气湿度以及生态系统植被含水量状态.因此,在高寒嵩草草甸生态系统,用地表水分指数反应生态系统尺度水分对光能利用效率的胁迫作用是可行的.     

川西高寒生态系统不同海拔土壤动物对冬季凋落叶腐殖化过程的影响

凋落叶在冬季的腐殖化过程是高寒生态系统土壤有机质形成和碳固定的重要阶段,并可能受到严酷冻结环境下仍具有一定活性的土壤动物的影响,但缺乏必要的关注。因此,以川西高山峡谷区海拔3000、3600、4000m的高寒森林和草甸典型凋落叶为研究对象,采用不同孔径大小的凋落物网袋去除土壤动物的方法,根据凋落叶的自然腐解过程,于2013年11月—2014年4月研究了不同冻融时期(冻结前期、深冻期、融化期)土壤动物对凋落叶腐殖化过程的作用。结果表明:通过对色调系数(Δlog K)和光密度值(E_4/E_6)值的分析,在高寒生态系统中,冬季随着温度的降低土壤动物促进了凋落叶的腐殖化,而随着温度的升高土壤动物抑制了凋落叶的腐殖化。深冻期土壤动物对海拔3000m的森林凋落叶腐殖化过程具有显著促进作用;在冻结前期土壤动物对海拔3600m森林凋落叶腐殖化过程具有显著促进作用;而融化期土壤动物对海拔4000m的草甸凋落叶腐殖化过程具有显著的抑制作用;其他海拔和时期没有显著影响。冻结初期土壤动物对凋落叶的腐殖化速率的作用高于深冻期和融化期,腐殖化度在深冻期达到最大值。这些结果表明气候变化情景下冬季变暖可能导致土壤动物抑制凋落物腐殖化,减少凋落物向土壤有机质的转化。     

Contribution of arbuscular mycorrhizal fungi of sedges to soil aggregation along an altitudinal alpine grassland gradient on the Tibetan Plateau

The diversity of arbuscular mycorrhizal fungi (AMF) in sedges on the Tibetan Plateau remains largely unexplored, and their contribution to soil aggregation can be important in understanding the ecological function of AMF in alpine ecosystems. Roots of Kobresia pygmaea C.B. Clarke and Carex pseudofoetida Kük. in alpine Kobresia pastures along an elevational transect (4149–5033 m) on Mount Mila were analysed for AMF diversity. A structural equation model was built to explore the contribution of biotic factors to soil aggregation. Sedges harboured abundant AMF communities covering seven families and some operational taxonomic units are habitat specific. The two plant species hosted similar AMF communities at most altitudes. The relative abundance of the two sedges contributed largely to soil macroaggregates, followed by extraradical mycorrhizal hyphae (EMH) and total glomalin‐related soil protein (T‐GRSP). The influence of plant richness was mainly due to its indirect influence on T‐GRSP and EMH. There was a strong positive correlation between GRSP and soil total carbon and nitrogen. Our results indicate that mycorrhization might not be a major trait leading to niche differentiation of the two co‐occurring sedge species. However, AMF contribute to soil aggregation and thus may have the potential to greatly influence C and N cycling in alpine grasslands.     

藏东南森林土壤微生物群落结构与土壤酶活性随海拔梯度的变化

【目的】针对青藏高原藏东南地区色季拉山不同海拔森林土壤,探讨微生物群落与土壤酶活性之间的联系以及受控因子。【方法】利用微生物细胞膜磷脂(PLFA)方法研究土壤微生物群落结构随海拔变化情况,分析土壤葡萄糖苷酶、酚氧化酶、蛋白酶、L-天冬酰胺酶、脲酶和酸性磷酸酶活性以及土壤理化性质随海拔的变化趋势。【结果】土壤理化性质和生化指标随海拔增高没有显著变化,如水分含量、有机碳、全氮、碳氮比、pH、无机氮和硝态氮,土壤葡萄糖苷酶、酚氧化酶、蛋白酶、L-天冬酰胺酶和酸性磷酸酶活性等;然而,微生物丰度呈现中峰优势分布规律,细菌、真菌、革兰氏阳性菌、革兰氏阴性菌和放线菌含量在海拔3 900 m和4 000 m处生物量显著高于低海拔和更高海拔。皮尔森相关性分析表明土壤pH是影响微生物群落结构的主要因子,但海拔梯度上的温度变化与微生物群落结构和酶活性不存在显著相关性;同时,有机碳、全氮、水溶性有机碳和水溶性有机氮和pH等理化指标与土壤酶活性显著相关。【结论】在藏东南色季拉山森林生态系统,海拔梯度对土壤微生物群落结构影响较大,土壤理化指标与生物特征对海拔梯度的响应较弱。     

Patterns and origin of intraspecific functional variability in a tropical alpine species along an altitudinal gradient

Background : Intraspecific functional variability (IFV) along altitudinal gradients is a powerful proxy to infer the responses of plants to abrupt environmental changes. We envisage that IFV shows distinctive patterns in tropical and extratropical alpine regions.

Aims : To characterise the patterns and explore the origin of IFV in a tropical alpine species in a context of upward range extension.

Methods : We examined variations in a series of plant functional traits in Lasiocephalus ovatus, inside and outside a nurse plant along a 600 m altitudinal gradient in the Ecuadorian Andes, and we studied its genetic variability.

Results : More conservative traits were developed at higher elevation, in contrast to extratropical alpine plants, which commonly develop opportunistic traits in response to late snowmelt close to their upper altitudinal limit. The presence of nurse cushions did not alter this trend. Increasing genetic distance along the gradient suggested that IFV might be partly genetically induced.

Conclusions : Our data combined with existing literature in tropical alpine environments lead the way to a stimulating scientific challenge: determining if patterns of plant altitudinal distribution in tropical alpine areas in response to climate change are predictable from patterns described in extratropical alpine areas.     

Impact of rainfall manipulations and biotic controls on soil respiration in Mediterranean and desert ecosystems along an aridity gradient

Spatially heterogeneous ecosystems form a majority of land types in the vast drylands of the globe. To evaluate climate‐change effects on CO₂ fluxes in such ecosystems, it is critical to understand the relative responses of each ecosystem component (microsite). We investigated soil respiration (R_s) at four sites along an aridity gradient (90–780 mm mean annual precipitation, MAP) during almost 2 years. In addition, R_s was measured in rainfall manipulations plots at the two central sites where ～30% droughting and ～30% water supplementation treatments were used over 5 years. Annual R_s was higher by 23% under shrub canopies compared with herbaceous gaps between shrubs, but R_s at both microsites responded similarly to rainfall reduction. Decreasing precipitation and soil water content along the aridity gradient and across rainfall manipulations resulted in a progressive decline in R_s at both microsites, i.e. the drier the conditions, the larger was the effect of reduction in water availability on R_s. Annual R_s on the ecosystem scale decreased at a slope of 256/MAP g C m^?2 yr^?1 mm^?1 (r²=0.97). The reduction in R_s amounted to 77% along the aridity gradient and to 16% across rainfall manipulations. Soil organic carbon (SOC) decreased with declining precipitation, and variation in SOC stocks explained 77% of the variation in annual R_s across sites, rainfall manipulations and microsites. This study shows that rainfall manipulations over several years are a useful tool for experimentally predicting climate‐change effects on CO₂ fluxes for time scales (such as approximated by aridity gradients) that are beyond common research periods. Rainfall reduction decreases rates of R_s not only by lowering biological activity, but also by drastically reducing shrub cover. We postulate that future climate change in heterogeneous ecosystems, such as Mediterranean and deserts shrublands will have a major impact on R_s by feedbacks through changes in vegetation structure.     

Soil properties along altitudinal gradient in Himalayan temperate forest of Garhwal region

The aim of the present study was to analyse the soil properties in different seasons at varying altitudes. The study was carried out in Dhanaulti forest, falls under temperate region of Garhwal Himalaya in Uttarakhand State, India. Physical properties and chemical properties of the soil were estimated using all standard procedures. In the present study, sand particles were reported highest (77.21%) in rainy season followed by in summer (70.17%) and winter (63.15%) seasons. The silt and clay particles also followed similar trend as sand which reduced in order of rainy > summer > winter seasons. The water holding capacity of soil ranged from 62.13 to 67.70%. The majority of soils were dark brown to dark yellowish brown in colour, which is considered having higher potential of water holding capacity. The values of nitrogen ranged between 0.01 to 0.012% (upper altitude), 0.009 to 0.011% (middle altitude) and 0.007 to 0.011% (lower altitude). The effects of altitudes and seasons in nitrogen show significant variation. Potassium ranged between 102.29 and 206.22 kg ha^? 1. The combined effect of season and soil-depth also showed significant variation in level of potassium. The soil organic carbon values were between 0.14 and 0.19% and pH values ranged between 6.33 and 6.75 which was slightly acidic in nature.     

Leaf wettability decreases along an extreme altitudinal gradient

The duration and amount of water captured on leaves and its functional significance is highly varied. Leaf surface wettability influences water absorption, gas exchange, pathogen infection, nutrient leaching, contamination by pollutants, self-cleaning properties and in freezing environments the probability of extrinsic ice nucleation. To test the impact of environment on the development of leaf wettability, this functional trait was measured in 227 dominant plant species along an extreme altitudinal environment gradient (186–5,268 m) on the wet and dry slopes of the Nepalese Himalayas. Plants from the understorey and open places in woodlands were also compared. Leaf wettability was assessed by droplet contact angle (θ), retention and leaf inclination measurement. With increasing altitude leaf wettability decreased significantly parallel to the observed atmospheric temperature decrease (0.5 K/100 m). Leaves from non-freezing tropical and subtropical origins were highly wettable (θ < 90°). Temperate leaves were non-wettable (110° < θ < 130°). Subalpine and alpine leaves were highly non-wettable (130° < θ < 150°) and adaxial pubescence occurred more frequently. Leaves taken from the understorey were more wettable but had a better droplet run off than leaves sampled in open places. In the semi-arid northern slopes (temperate to alpine) of the Himalayas leaf wettability was decreased in comparison to the southern humid side. The majority of the leaves had a low droplet retention <20°; higher values were linked to high non-wettability (θ > 130°) which was more often observed at high altitude. Good droplet run off at ±10° inclination was found in highly wettable leaves (θ < 90°) of tropical and subtropical origin and on leaves from the forest understorey. Structural properties for low wettability are developed in cold and dry environments and open sites with frequent dew formation as it appears to be an important functional trait to prevent a number of the negative effects adhering surface water may have.     

Geomorphological disturbance affects ecological driving forces and plant turnover along an altitudinal stress gradient on alpine slopes

The altitudinal gradient is considered as a stress gradient for plant species because the development and fitness of plant communities tend to decrease as a result of the extreme environmental conditions present at high elevations. Abiotic factors are predicted to be the primary filter for species assemblage in high alpine areas, influencing biotic interactions through both competition for resources and positive interactions among species. We hypothesised that the relative importance of the ecological driving forces that affect the biotic interactions within plant communities changes along an elevation gradient on alpine debris slopes. We used multiple gradient analyses of 180 vegetation plots along an altitudinal range from ~1,600 to 2,600 m and single 100 m-bands in the Adamello-Presanella Group (Central Alps) to investigate our hypothesis; we measured multiple environmental variables related to different ecological driving forces. Our results illustrate that resource limitations at higher elevations affect not only the shift from competition to facilitation among species. A geomorphological disturbance regime along alpine slopes favours the resilience of the high-altitude species within topographic/geomorphological traps. An understanding of the ecological driving forces and positive interactions as a function of altitude may clarify the mechanisms underlying plant responses to present and future environmental changes.     

Effects of roads on alpine and subalpine plant species distribution along an altitudinal gradient on Mount Norikura, central Japan

We investigated the effects of roads on alpine and subalpine plant species distribution along an altitudinal gradient on Mount Norikura (3026 m a.s.l.), Japan. We examined the vegetation of herb and tree species shorter than 1.3 m along roadsides and adjacent natural vegetation at 200 m intervals between 1600 and 3000 m a.s.l. The timberline was at 2500 m a.s.l. Although the canopy opening was greater at the roadsides than in the natural vegetation, it was similar above the timberline. Soil cover and litter depth of the soil surface were less at roadsides than the natural vegetation, and gravel and rock cover were greater at roadsides. Species composition changed in similar directions from natural vegetation to roadsides along the altitudinal gradient. This direction was related to canopy opening and litter depth. Liliaceae, Ericaceae and Pinaceae were dominant families in the natural vegetation, and Asteraceae and Poaceae were greatest at the roadsides. Roadside plants were mostly herb species, while tree species increased in natural vegetation. Five exotic species were also observed at the roadsides. Sunny plant species gradually increased with altitude in the natural vegetation, indicated by the increase in canopy opening. By contrast, roadside plants were mostly sunny plant species irrespective of altitude. The number of lowland and montane species increased at the roadsides in the subalpine zone. Thus, roads strongly altered species composition of the natural vegetation along the altitudinal gradient probably because of changes in light and soil-surface conditions for growth and seedling establishment.     

Leaf size zonation pattern of woody species along an altitudinal gradient on Mt. Pulog,Philippines

Leaf size zonation along an altitudinal gradient from 2000–2700 m a.s.l. on Mt. Pulog, Cordillera mountain range, Luzon Is., Philippines was examined using the Raunkiaer-Webb classification system. The entire altitudinal range studied was dominated by the small leaf size classes which possess thick, lustrous, pubescent leaves adapted to high evapotranspiration, cold temperature and other stressful conditions. Altitudinal leaf size zonation was identified as follows: (1) pure needle leaved zone from 2000–2300 m a.s.l., (2) mixed needle leaved/microphyllous zone from 2300–2400 m a.s.l., (3) microphyllous zone from 2400–2600 m a.s.l. and, (4) microphyllous/nanophyllous zone from 2600–2700 m a.s.l., coinciding with the altitudinal vegetation zonation. This pattern is different from that in other tropical mountains, which usually show a gradual shift from a mesophyllous zone in the lowland to a nanophyllous zone in the upper subalpine. Stressful conditions such as steep topography (1200–2300 m a.s.l.), cloud cover, decrease of temperature, strong winds (2600–2700 m a.s.l.) could have influenced the altitudinal leaf size zonation on Mt. Pulog. The complex phytogeographical position of Mt. Pulog as a transition region between the tropics and subtropics have also influenced leaf size zonation as in eastern Himalaya, southwestern China and Taiwan.     

新疆喀纳斯树种丰富度垂直格局特征

采用样带调查法,通过直接梯度、变异函数和分形函数分析,对新疆喀纳斯旅游区内设置的3条样带的树种比例及树种丰富度沿海拔梯度的变异特征进行了研究。结果表明：直接梯度刻画的不同树种所占比例在海拔梯度上的变化趋势各异;树种丰富度在整个调查尺度范围内随海拔的升高呈现明显的下降态势（P＜0.01）;半方差分析揭示：树种丰富度在中小尺度范围内的空间异质性主要由空间自相关引起的变异组成;分维分析反映出树种丰富度的分形维数偏大,且在中小尺度范围内无拐点,说明树种丰富度受随机生态学过程的影响在相应尺度范围内具有很强的空间异质性。     

The leaf size-twig size spectrum of temperate woody species along an altitudinal gradient: an invariant allometric scaling relationship

BACKGROUND AND AIMS: The leaf size-twig size spectrum is one of the leading dimensions of plant ecological variation, and now it is under development. The purpose of this study was to test whether the relationship between leaf size and twig size is isometric or allometric, and to examine the relationship between plant allometric growth and life history strategies in the spectrum. METHODS: Leaf and stem characters-including leaf and stem mass, total leaf area, individual leaf area, stem cross-sectional area, leaf number and stem length-at the twig level for 59 woody species were investigated along an altitudinal gradient on Changbaishan Mountain in the temperate zone of China. The environmental gradient ranges from temperate broad-leaved mixed forest at low altitude, to conifer forest at middle altitude, and to sub-alpine birch forest at high altitude. The scaling relationships between stem cross-sectional area and stem mass, stem mass and leaf mass, and leaf mass and leaf area at the twig level were simultaneously determined. KEY RESULTS: Twig cross-sectional area was found to have invariant allometric scaling relationships with the stem mass, leaf mass, total leaf area and individual leaf area, all with common slopes being significantly larger than 1, for three altitudinal-zoned vegetation types under investigation. However, leaf mass was found to be isometrically related to stem mass and leaf area along the environmental gradient. Based on the predictions of previous models, the exponent value of the relationship between twig cross-sectional area and total leaf area can be inferred to be 1.5, which falls between the confidence intervals of the relationship at each altitude, and between the confidence intervals of the common slope value (1.17-1.56) of this study. This invariant scaling relationship is assumed to result from the fractural network and/or developmental constraints of plants. The allometric constants (y-intercepts) of the relationships between the stem cross-sectional area and leaf area (both total leaf area and individual leaf area) were found to decrease significantly along the altitudinal gradient. This suggests that the species would support less leaf area at a given twig cross-sectional area with increasing environmental stress. CONCLUSIONS: This study demonstrated that plants respond to the environmental gradient by changing the y-intercepts of the relationship between leaf size-twig size, while keeping the exponent value of the allometric relationship as an invariant constant. The allometric growth in the twig size-leaf size spectrum is related to many other components of plant life history strategy, including the well established life history trade-off between efficiency and safety in the hydraulic transport of water.     

Local adaptation and cogradient selection in the alpine plant, Poa hiemata, along a narrow altitudinal gradient

Alpine environments are particularly susceptible to environmental changes associated with global warming but there is potential for alpine plants to adapt to warming if local adaptation occurs and gene flow allows genotypes adapted to low altitudes to colonize higher altitude sites. Here we examine the adaptive potential of a common alpine grass, Poa hiemata, within the restricted alpine habitat of Australian mountains, across a narrow altitudinal gradient replicated in three areas. Grasses at high altitude sites had shorter leaf lengths and larger circumferences than those at lower sites. Transplant experiments with clonal material and plants grown from seed indicated that these differences were partly genetic, with environmental and genetic factors both contributing to the differences between altitudes. Differences in altitudinal forms were also evident in a common garden experiment. Plants showed a home-site advantage in terms of survival. A fitness analysis indicated that at high altitude sites, selection favored plants with short leaves and larger circumferences, whereas these traits were selected in the opposite direction at the low altitude sites. These findings indicate cogradient selection and potential for both plastic and genotypic shifts in response to climate change in P. hiemata.     

Comparison of soil seed banks of habitats distributed along an altitudinal gradient in northern Iran

In this study we investigated the variations in soil seed banks along an altitudinal gradient in the Alborz mountains, Iran, covering three habitats from lower to upper altitudes: forest, forest-subalpine grassland ecotone and subalpine meadow. In each habitat from 1850 to 2400 m, 20 quadrats were established along four transects, and the above-ground vegetation and the germinable seed banks were determined. Results show that the similarity between seed bank and vegetation was lowest in the ecotone located at intermediate altitudes. Together with the contrasting highest density and species diversity of seeds at these altitudes, the ecotonal role of this habitat was confirmed.We found evidence that lower altitudes could act as storage for seeds of some species growing at higher altitudes; the role of the ecotone was more prominent as a reserve for the meadow plant seeds than the role of the forest as a reserve for seeds of the meadow and ecotone habitats. Soil seed banks, particularly from the ecotone, can be used for restoring vegetation in some degraded sites.     

雅鲁藏布江上游高寒草甸地上生物量与多样性沿海拔梯度的变化特征

【目的】雅鲁藏布江是青藏高原最重要的河流,研究雅鲁藏布江的地上生物量和物种多样性对了解该区域的草地资源和生态保护具有重要意义。【方法】文章根据海拔梯度对雅鲁藏布江上游高寒草甸植被特征进行调查,研究不同海拔梯度下地上生物量和物种多样性的分布差异、地上生物量与物种多样性之间的关系,以及相关环境因子对地上生物量和物种多样性的影响。【结果】(1)海拔与地上生物量无显著关系;(2)海拔与多样性指数呈显著负相关关系,随海拔升高Shannon-Weiner指数、Patrick指数表现为下降趋势;(3)地上生物量与多样性之间表现为负相关关系,Shannon-Weiner指数对地上生物量的解释达到70%(P＜0.01);(4)物种多样性与温度和降水呈显著正相关关系(P＜0.05),物种多样性与海拔呈负相关关系(P＜0.05),地上生物量与海拔、温度和降水无显著关系(P＞0.05)。【结论】该研究结果有助于为雅鲁藏布江上游流域草地资源的合理利用和物种多样性保护提供依据。     

长白山森林生态系统凋落物层和土壤层跳虫物种多样性和功能多样性对海拔梯度的响应

山脉是生物多样性研究的热点地区,以往关于山脉的研究多集中于地上植物和脊椎动物,无脊椎动物相关的研究明显滞后。跳虫(Collembola)是土壤无脊椎动物的主要类群之一,在分解有机质、疏松和活化土壤过程中发挥着重要的作用。以跳虫为研究对象,采用梯度格局法,在长白山北坡自海拔800 m至1700 m,每隔150 m进行凋落物层和土壤层样品的采集,对比分析了土壤层和凋落物层的群落组成与群落结构,采用4个物种多样性指数(丰富度指数、Pielou均匀度指数、Shannon-Weiner多样性指数和Simpson多样性指数)和4个功能多样性指数(功能丰富度FRic指数、功能均匀度FEve指数、二次熵Rao''s Q指数和功能离散FEiv指数),探讨了多样性沿海拔梯度的分布格局。共获得跳虫5542头,隶属于12科42属83种,其中等节跳科为绝对优势类群(相对密度>50%)。非度量多维尺度分析结果表明,凋落物层和土壤层的跳虫群落结构差异显著,长角跳科、鳞跳科和疣跳科物种多分布于凋落物层,而棘跳科物种多分布于土壤层。线性或二次回归模型结果表明,在凋落物层跳虫的丰富度指数,Shannon-Weiner多样性指数和Simpson多样性指数沿海拔梯度的变化呈增加格局;但在土壤层跳虫物种多样性指数沿海拔梯度的变化无明显趋势。在凋落物层,跳虫的功能丰富度指数和功能离散度Rao''s Q指数随海拔梯度的变化呈现单峰分布格局;在土壤层,跳虫的功能丰富度指数随海拔梯度的变化也呈现单峰分布格局,但其他功能多样性指数沿海拔梯度的变化无明显趋势。研究表明凋落物层和土壤层跳虫的群落组成,群落结构及多样性存在显著差异,跳虫的物种多样性指数和功能多样性指数对海拔梯度变化的响应不同,未来在探讨土壤动物沿海拔梯度的分布格局及其物种共存机制时,应综合考量垂直分层(凋落物层和土壤层)和多个度量维度(物种多样性和功能多样性)。     

青藏高原高寒草甸不同海拔土壤酶化学计量特征

土壤酶在生态系统物质循环和能量流动中起着关键作用,研究土壤酶活性对于探讨生态系统功能有着重要意义.采用Biolog微平板技术,研究不同海拔(4300～5100 m)土壤酶活性和酶计量比的变化特征及影响机制.结果表明:与C循环密切相关的β-1,4-葡萄糖苷酶(βG)、与N循环密切相关的β-1,4-N-乙酰氨基葡萄糖苷酶(NAG)、L-亮氨酸氨基肽酶(LAP)以及与P循环密切相关的酸性磷酸酶(AP)活性均随海拔升高呈现先上升后下降的单峰变化趋势,整体表现出4800 m>4950 m>4400 m>4650 m>5100 m>4300 m;土壤N∶P酶活性比呈现与土壤酶活性相同的先上升后下降单峰变化趋势,在4950 m处达到最高值;而土壤C∶N和C∶P酶活性比表现出沿海拔升高逐渐增加的趋势.有机碳(SOC)、土壤全氮(TN)、土壤含水量与4种酶活性均呈显著正相关;年均温度与NAG、AP呈显著正相关;年降水量与NAG、AP呈显著负相关;土壤C∶P酶活性比、土壤N∶P酶活性比与年均温度、年降水量、植被Shannon多样性指数、植被丰富度指数、植被盖度和TN呈显著正相关.年均温、年降水量、植被丰富度、植被覆盖度、土壤全氮和溶解性有机碳显著影响土壤C∶N酶活性比.青藏高原草甸不同海拔土壤酶活性和酶计量比呈现显著的海拔差异,且高海拔地区存在一定的N限制.土壤酶活性海拔差异主要受到土壤含水量、TN、SOC、年降水量和年均温度的影响.