螺髻山自然保护区非飞行小型哺乳动物垂直多样性调查

2009 年4 ～8 月利用铗日法对螺髻山自然保护区非飞行小型哺乳动物的多样性进行了调查。调查于海拔1 800 ～4 150 m间按梯度设置7 个采集样地,每个采集样地内设3 个样带并置铗,有效布铗10 500铗次,捕获非飞行小型哺乳动物5 科8 属15 种,共491 个个体。调查结果表明,调查区域内非飞行小型哺乳动物群落的相对丰富度、丰富度和多样性指数均与海拔存在显著的相关性。统计分析显示:位于阴坡且与水源地相距较近的样地的物种相对丰富度明显高于位于阳坡、距离水源地远的样地;植被类型丰富、降水量充分的中海拔地区(2 200 ～ 2 600 m) 相对丰富度、丰富度和多样性达到最高;而在高海拔(> 3 800 m) 和低海拔区域(< 2 000 m)则较低。非飞行小型哺乳动物的多样性以中低山阔叶灌丛林与亚热带针阔混交林中最高,而在高山流石滩、高山草甸与河谷灌草丛中较低。在本研究的调查区域内,中海拔地区多样性和丰富度最大可能是非飞行小型哺乳动物垂直多样性分布的一个重要特点。     

不同地区春播小麦生育天数的对比试验

1983至1985年,在石家庄、榆林、银川、张掖进行了小麦生态研究的春播试验。这4个试点的纬度基本相同,但经度和海拔差别较大。绵阳11号属于春型小麦品种。在春播试验中,参试品种在不同地点的播种至成熟天数有明显差异。试验表明,在我国北纬38—39度之间的不同地点,海拔每升高100米,小麦生育期间的平均日均温约降低0.3℃,生育天数约增加2—3天,经度每增加1度,小麦的生育天数约减少2天。     

Increasing temperature sensitivity caused by climate warming,evidence from Northeastern China

The “Divergence Problem” in northern forests has been confirmed in a large number of empirical studies, especially in North America and Europe, climate warming having been identified as a cause for reduced sensitivity of recent tree-growth and increased tree mortality. However, according to other studies, tree growth patterns are keeping pace with climate warming. Covariation between rising temperatures and tree growth varies regionally. Therefore, extensive evidence is still needed across more geographic areas around the world. In the present study, we examined the sensitivity of Manchurian ash forest growth, which is one of the dominant species in the mixed coniferous and broad-leaved forests in the area around Changbai Mountain in Northeastern China. Five Manchurian ash tree-ring width chronologies were constructed from sites ranging along the elevational gradients of 750 m, 800 m, 900 m, 1000 m and 1100 m. We analyzed climate-growth relationships using Pearson correlation coefficients between ring-width indices and climate variables in two separate periods (before 1984 and after 1984), because instrumental temperature data have increased sharply after 1984. Along all of the elevational gradients, the sampled Manchurian ash forests show a higher growth rate and more sensitivity to climatic factors due to climate warming since the beginning of the 1984s. Comparatively, the forest growth at low elevation sites has increased faster than that at high elevation sites. If climate warming continues in northeastern China, further continuous and substantial increase in tree growth would substantially raise forest productivity in mixed coniferous and broad-leaved forests.     

高寒草甸群落植物多样性和初级生产力沿海拔梯度变化的研究

 对不同海拔梯度高寒草甸群落植物多样性和初级生产力关系的研究结果表明：1）不同海拔梯度上,中间海拔梯度群落植物多样性最高,即物种丰富度、均匀度和多样性最大;2）不同海拔梯度上,群落生产力水平和物种丰富度中等时,物种多样性最高;3）随着海拔的逐渐升高,地上生物量逐渐减少;4）地下生物量具有“V”字形季节变化规律,在牧草返青期和枯黄期地下生物量最大,7月最小,且地下生物量主要分布在0～10 cm的土层中。地下生物量垂直分布呈明显的倒金字塔特征。     

种子重量与海拔的相关性分析：

种子重量与海拔的关系是植物生态学中重要而尚存争议的问题。本文对中国123科853种2879份野生植物种子的重量在海拔上的变化特点以及二者之间的相互关系进行了深入研究,结果显示：种子重量总体上与海拔呈负相关,种子重量级别多样性和生活型多样性随海拔上升呈阶梯状下降。但7级种子中,只有10。级种子的重量与海拔呈负相关;7种生活型中,只有灌木和匍匐草本的种子重量与海拔呈负相关;在种水平上,只有8．2％的物种种子重量与海拔存在相关性。本研究揭示了我国种子重量与海拔之间的复杂关系,以及遗传和环境对种子重量的影响,对植物育种、森林管理以及入侵植物的防治具有一定指导意义。     

Use of stereo aerial photography for quantifying changes in the extent and height of mangroves in tropical Australia

The study investigated the use of aerial photographs, acquired in 1950 and1991, for assessing the temporal dynamics of mangroves along the WestAlligator River in Australia's Northern Territory. For both years,mangrove extent was mapped using an unsupervised classification of thedigital orthomosaic and Digital Elevation Models (DEMs), or height maps,of the mangrove canopy were derived from stereo pairs. Helicopter andfield observations in 1998 and 1999 respectively provided ground truthfor interpreting the derived datasets. The comparison of mangrove extentrevealed a substantial movement over the 41-year period, perhaps inresponse to hydrological changes that have resulted in a landward extensionof saline conditions. Changes in the height of mangroves were observedbut were difficult to quantify due to the reduced quality of the 1950 DEM. The study demonstrated the viability of using time-series of aerialphotography for monitoring and understanding the long-term response ofmangroves to environmental change, including hydrological variations andsea level rise.     

Pollen representation of vegetational patterns along an elevational gradient

Abstract. Modern pollen assemblages from 16 small lakes (< 2.5 ha) and 11 moderate-sized lakes (4.5–19.3 ha) arrayed along an elevational gradient (300 to 1320 m) in the east-central Adirondack Mountains were studied to determine how well the pollen assemblages recorded patterns of forest composition along the gradient. Forest composition ranges from Pinus strobus/Tsuga/ hardwoods forests at low elevations through Tsuga/ hardwoods, hardwoods, and Picea/Abies forests to Abies-dominated forests at high elevations. Modern pollen percentages for 10 tree taxa were compared with lake elevation using scatter plots and correlation and regression analysis. Differential smoothing of vegetational patterns along the elevational gradient occurred among the 10 taxa owing to differences in pollen dispersibility, pollen production, and spatial pattern of taxon abundance in forests of the region. No differences were observed in pollen-elevation patterns between small and moderate-sized lakes. Pollen-elevation patterns were obscured for most taxa when the gradient was shortened (e.g. to 600–1320 m) owing to increased spatial smoothing by pollen dispersal. Design and interpretation of paleoecological studies of spatial gradients can be improved by careful attention to site spacing, gradient length, and gradient steepness in the context of pollen dispersal and representation models.     

甘肃马衔山林区植被的数量分类与排序

 本文用目前各国学者广泛使用的一些数量分类和排序方法对黄土高原区的马衔山植物群落进行了分类和排序。所用方法包括多元等级分划分类(TWINSPAN程序)、PCA排序(ORDINA程序)、RA和DCA排序(DECORANA程序)。研究结果表明可以把32个样地分为两大类共7个群落类型：山地森林 (1)山杨+白桦群落,(2)青杆群落,(3)青杆+白桦+山杨群落,(4)山杨+康定柳+糙皮桦群落;山地灌丛 (1)康定柳+糙皮桦群落,(2)糙皮桦+黄毛杜鹃+裂香杜鹃群落,(3)黄毛杜鹃+裂香杜鹃群落。它们的分布格局与海拔梯度密切相关。此外,本文还对所用方法的比较进行了讨论。     

Scale and species-environment relationships in a central Himalayan oak forest,Nepal

A quantitative gradient study in a central Himalayan mixed Quercus forest (Q. semecarpifolia and Q. lamellosa) was made to evaluate the relationships between environmental variables and species composition at different scales.The data (91 taxa × 120 sub-plots) were sampled at three sites, where groups of four sub-plots (2.5 m × 2.5 m) were sampled within 10 m × 10 m. The species data were analysed together with the environmental data (elevation, relative radiation (RI) and soil variables) using Correspondence Analysis (CA) and its constrained version (CCA). The environmental variables used in CCA were chosen by forward selection.Elevation was the over-riding complex gradient (2000–3000 m a.s.l.), with loss-on-ignition, total nitrogen, and RI covarying. The most important factors independent of elevation were available phosphorus and tree canopy cover, whereas pH and nitrogen had minor independent influences.The overall species environment correlation was highest for the largest plot size. The species environment correlation increased with spatial extent for the largest plot size. The field-layer and shrub-tree strata did not consistently differ in their concordance between species and environment. The field-layer species had a stronger relationships with the soil variables, which may relate to rapid changes over a short spatial extent both for the field-layer species and for the soil variables.     

The environmental control of plant species density on a Himalayan elevation gradient

Aim In eastern Nepal, forests occupy an elevation gradient of 4000 m with bioclimatic zones from near tropical to alpine. Understorey plants and trees were censused to measure species density and identify patterns of ecological change. By sampling in a manner robust against spurious mid‐domain effects, I aim to identify biologically valid controls on species density. Location The study area consists of land below 4250 m elevation between 27.1 and 27.8° N latitude, 86.5 and 88.0° E longitude on the southern slopes of the Himalaya Range in eastern Nepal. Sampling sites are limited to intact, natural forest with relatively little human impact. Methods Team members counted species of understorey plants and trees ≥ 10 cm d.b.h. in 0.04 ha plots throughout the study area. In addition, basal area, leafing phenology and species composition were determined for the trees in each plot. Estimates of regional species density were compiled for successive 250 m elevation bands from 250 to 4250 m elevation. Species density trends were identified and compared with the expectations of O'Brien's [Journal of Biogeography 25 (1998) 379–398] climate‐based water–energy dynamics model. Results Stand basal area, tree leafing phenology and taxonomic composition (angiosperm vs. gymnosperm) show non‐random change with elevation. Understorey plant and tree species density both have a humped, unimodal trend with more species near the bottom of the gradient and fewest at the top. These trends are consistent with expected effects of the climatically active water and energy variables. After curve‐fitting, significant spatial structure in the residuals suggests that tree communities within the 1750–2250 m elevation range do not realize their climatic potential species richness. Main conclusions Neither mid‐domain effects nor biologically valid boundary effects like dispersal limitation explain the plant species density trends observed. Trends do fit a model in which species density is controlled by the same ‘active’ climatic variables that predict species richness on continental scales. Patterns of leafing phenology on the elevation gradient provide further support for the hypothesis of environmental control of species density. The productivity–diversity linkage that exists on continental scales may also apply on the smaller scale of a Himalayan elevation gradient. Human activity and possible competitive exclusion by Castanopsis tribuloides are the two best explanations for the observed decline in tree species density at 1750–2250 m elevation. Burning, lopping for fodder and livestock grazing might account for the decline, but this study does not assess the relative importance of these activities. The elevation richest for understorey plant and tree species (500–1500 m) also has the most severe reduction in forest cover. Local farmers deserve credit for sustaining plant biodiversity in forest enclaves, but further loss of forest at these elevations should be discouraged.