栽培药材川续断地上部分体积估算的最优样方选择

以贵州省黔南州龙里县内人工栽培的川续断(Dipsacus asperoides)为研究对象, 就如何选择最优样方的面积和数目来估算川续断地上部分体积进行了研究。首先运用球缺模型计算栽培川续断的地上体积, 然后利用基于套状样方的样带调查法研究估算川续断体积时的最优样方面积, 最后利用方差法计算最优采样数目。结果表明: (1)在只考虑相对平均值和相对消耗时, 25 m × 25 m是最优样方面积; 在此基础上进一步考虑到样方的边界效应和单位面积地上体积相对平均值的变化, 得出25 m × 50 m是最优样方面积。(2)如果预计置信度1-α是0.9, 绝对误差限度d是0.12, 总体方差S²按照常规取0.25, 则25 m × 50 m对应的最佳样方数目是25。(3)该研究实际采集了25个25 m × 50 m的样方, 计算后得到整个栽培园地(面积为72696.24 m ²)川续断的总体积90%的近似置信区间为[1909.798 m³, 2214.762 m³]。     

西藏高原高寒草地群落植物多样性和地上生物量监测方法的比较研究

以西藏高原高寒草地3种植被类型(高寒草甸、高寒草原和高寒荒漠草原)为研究对象,分别采用样线法、样方法和巢式样方法进行实地调查,记录每条样线上或每个样方内出现的所有物种,并分物种刈割样方内地上部分,通过统计分析比较不同高寒草地群落植物多样性和地上生物量监测方法,以阐明西藏高原高寒草地不同植被类型的最小取样面积和最少样方数或样线长度。结果显示:(1)就物种丰富度而言,400m样线法观测到的高寒草甸、高寒草原和高寒荒漠草原的所有物种数分别占3种方法调查到的总物种数的55%、71%和50%;8m2巢式样方法调查到高寒草甸、高寒草原的总物种数占所有3种方法观测的物种总数的57.5%和57%,而8m2的巢式样方对高寒荒漠草原的调查监测到的物种数最多,其中2m2观测到的物种数就达到所有可能出现物种的83%;20个样方法监测到高寒草甸和高寒草原的物种数最多,占3种方法观测到总物种数的78%和86%,所以对物种丰富度的调查高寒草甸和高寒典型草原至少需要20个样方,高寒荒漠草原需要最小面积不少于2m2的2个样方。(2)就地上生物量而言,由地上生物量与物种数之间的变异关系得出最小样方数为7~11个,而由地上生物量的变异系数可知,在变异系数小于等于5%的前提下,高寒草甸的最小取样面积不小于0.25m2,高寒典型草原和高寒荒漠草原的最小取样面积不少于1m2。研究表明,对于生产力的监测方法而言,高寒草甸采用10个0.5m×0.5m的样方,而高寒草原和高寒荒漠草原采用10个1m×1m的样方为宜;而对于物种丰富度的监测方法而言,高寒草甸以20个0.5m×0.5m的样方和高寒草原20个1m×1m的样方为宜,高寒荒漠草原采用2个不小于2m2样方面积为宜。     

地表火对呼伦贝尔沙地樟子松林林下植物多样性的影响

选择无地表火发生、当年发生地表火和地表火发生后12 a的天然樟子松林分,利用多尺度、面积1 000 m2改进的Whittaker样方,研究了地表火对呼伦贝尔沙地天然樟子松(Pinus sylvestris L.var.mongolica Litv.)林林下植被多样性的影响.结果表明,各林分所有林木的平均胸径(DBH)差异极显著(P<0.01).在1 m2样方尺度上,3种林分的林下植被盖度有极显著差异(P<0.000 1),其中地表火发牛后12 a的林分林下植被盖度最低(32.0%).在面积1和10 m2样方尺度上.各林分林下植被的α多样性有显著差异(P<0.05),且以当年发牛地表火的林分林下植被丰富度最高;不同功能群植物(包括木本植物、禾本科植物和非禾本科草本植物)的α多样性也仅在小尺度上有一定的差异.林下植被的β多样性随火后持续时间的延长不断增加,无地表火发生的林分β多样性最高.间接梯度分析(DCA)结果表明,当年发生地表火的林分中植物种类较多,林下植物均表现出从偏旱生到偏湿生、沿水分梯度分布的趋势.因此,樟子松林下植被多样性仅在小尺度上对地表火干扰产生响应,随着时间的推移其多样性趋于一致,表明天然樟子松林的林下植被具有抵御地表火干扰的能力.     

荒漠绿洲过渡带植被空间异质性的可塑性面积单元问题

 以荒漠绿洲过渡带植被为研究对象,采用地统计理论与方法,以优势植物泡泡刺(Nitraria sphaerocarpa)和红砂(Reaumuria soongorica)种群为例,采用一个样地内2 500个10 m×10 m小样方中获取的植物盖度数据来研究采样尺度和划区方式对荒漠植被空间异质性的影响。其中尺度效应研究的思路是：一是保持粒度（样方）不变,增加幅度（样地）分析其对空间异质性的影响;二是保持幅度不变,改变粒度进行分析。划区效应是在样地尺度（500 m×500 m）上,把整块样地数据聚合成10 m×200 m、20 m×100 m、40 m×50 m、50 m×40 m、100 m×20 m和200 m×10 m等不同形状和不同方向的网格进行地统计分析。结果表明：荒漠绿洲过渡带植被空间异质性受采样尺度和划区方式影响显著。当样地面积小于200 m×200 m 时,所获取的数据不能真实反映泡泡刺种群的空间异质性;当样地面积小于100 m×100 m 时,所获取的数据不能真实反映红砂种群的空间异质性。调查泡泡刺和红砂种群的空间格局时,样方面积在20 m×20 m到30 m×30 m较为合适。植被空间异质性参数对划区方式的敏感性较强,其中泡泡刺种群的敏感性高于红砂种群。     

样方面积和数量对测定次生林凋落物精度的影响

经研究林地凋落物的重量分布特征,发现其总体分布具有偏态分布的特点。在中间区段(约为湿重 1.5S),凋落物重量在林地具有均匀分布的若干性质。测定林地凋落物累积量时,在27°山坡上,当样方面积超过0.5m~2后,所需样方数目渐趋稳定。因此建议设置样方时面积以为0.5—1.0m~2为佳。本文还计算出样方面积不同时,为保证一定精度所需的最少样方数。只要能够达到这一数目,任何大小的样方都能满足精度的需要。最后,通过研究坡度对凋落物收集的影响,可以看出,随坡度增大,林地凋落物重量的变异程度增加,同一取样面积上需设置的最小样方数目也随之增加。     

小兴安岭红松针阔叶混交林取样技术的研究

本文研究了小兴安岭红松针阔叶混交林的取样技术。通过对三个群落类型的取样研究,认为所应用的无样地方法适用于该植被类型。研究结果指出,应用无样地方法中的中点象限法,其最小点数是16—18个点,点间距为15m,样线间距为20m。16—18个样点的数据,相当于 600m2的样地资料。林下植被的最小面积是28—32m2,为7—8个2×2(m)随机或均匀分布的样方。     

种群分布格局测定的样方尺度效应

以粤西黑石顶自然保护区西部船底窝的永久样地为研究对象,在一个面积为1600m2的人工次生裸地样地上,借助地理信息系统(GIS)技术,对各个种群分别用3种不同的样方面积(10m×10m,8m×8m,5m×5m)和不同的测定方法来研究演替初期优势种群的分布格局,从而研究不同的样方面积对测定南亚热带森林群落内种群分布格局的影响。结果表明,在南亚热带森林群落演替初期以8m×8m的样方面积来测定种群分布格局较为有效。同时运用GIS技术作数据处理及图形输出,大大简化了分析过程,提高了分析水平。     

地面测量与ASTER影像综合计算植被盖度

选择我国北方温带典型草原作为研究对象,在研究区内分别针对植被盖度是高、中、低的地区随机选取49块样地,在每块样地内采用嵌套的方式作样方,样方尺度有60、30、15m3个尺度,嵌套的方式是60m的样方嵌套30m的样方,30m的样方嵌套15m的样方。15m的样方内作3个1m的样方,30m的样方内作5个1m的样方,60m的样方内作10个1m的样方。对于每个1m的样方,采用将数码相机架设在离草本层2m高的位置,垂直对样方进行拍摄,并记录影像的方式估计植被盖度。基于以上地面实测数据以及ASTER遥感数据,建立植被盖度经验模型。模型建立的步骤主要包括以下内容：（1）利用植被盖度信息提取模型计算野外实测的各张数码相片的植被盖度值,在15、30m以及60m3个样方尺度上计算各样方的植被盖度;（2）计算ASTER数据的各种植被指数（RVI,NDVI,NDGI）;（3）将地面样方与相应的ASTER影像像元在不同的尺度上相匹配。（4）基于某一样方尺度,计算与地面样方相对应区域内的ASTER影像像元植被指数的中值。（5）基于该样方尺度,建立地面实测植被盖度值与ASTER数据植被指数值之间的回归模型;（6）对回归模型进行显著性检验。在建立经验模型的过程中,研究植被指数（NDVI、NDGI以及RVI）与植被盖度的相关性以及地面样方尺度对经验模型的影响。此外,还将经验模型与目前广泛使用的亚像元分解模型作比较,检验亚像元分解模型在中国北方温带典型草原的适用性。结果表明,（1）对于中国北方典型草原区而言,利用植被指数NDVI监测草地的植被盖度是比较适宜的,它优于植被指数RVI,也比植被指数NDGI的效果好。（2）地面样方尺度的选择对于植被盖度经验模型的建立有很大的影响。就中国北方典型草原区来看,在地面作大样方,取其中值的方法在一定程度上可以克服由于地面的测量和遥感测量之间发生空间错配而产生的影响,有利于提高植被指数与植被盖度之间相关系数的显著水平。（3）60m×60m的样方尺度,基于NDVI的植被盖度经验模型相比,利用亚像元分解模型估测中国北方温带典型草原植被盖度的精度低于前者。     

乌兰布和沙漠东北缘荒漠-绿洲过渡带植被地上生物量估算

干旱区荒漠植被地上生物量是植被生长状况评价与荒漠化监测的重要指标。在乌兰布和沙漠东北缘的荒漠-绿洲过渡带选取典型区,基于地面调查数据构建主要植物种的异速生长方程,对样方内的植被地上生物量进行估算;基于样方调查数据和Quick Bird影像数据,分别建立植被指数与人工固沙林和荒漠植被地上生物量的回归模型,并对研究区植被地上生物量进行估算。结果表明:植冠体积V是较好的预测变量,所得荒漠植物异速生长方程精度较高,能够满足样方内荒漠植被地上生物量估算需要;采用RVI对数模型估算人工固沙林地上生物量的效果最好(R~2=0.72,RMSEP=56.15),采用RVI线性模型估算荒漠植被地上生物量的效果最好(R~2=0.82,RMSEP=15.07);研究区内荒漠植被和人工固沙林的单位面积地上生物量分别为90.73g/m~2和105.28g/m~2。该研究可以为荒漠化监测和荒漠植被遥感信息提取提供参考。     

马尾松人工林林分密度对林下植被及土壤性质的影响

采用样方调查及取样分析方法,研究广西大青山南亚热带不同密度马尾松人工林林下植被及土壤特征.结果表明:马尾松人工林自然发育14 a后,林分密度从1050 株·hm^-2增加到1800株·hm^-2,林下灌木层物种多样性指数增高.密度为1800 株·hm^-2时,多样性指数最高.当林分密度继续增大到2250 株·hm^-2,灌木层物种多样性指数却呈降低趋势.林下草本物种多样性指数对林分密度变化的响应不敏感;在林分密度影响下,林下灌木生物量与灌木层物种多样性指数变化规律一致.随着林分密度的增大,林下草本生物量呈降低趋势;不同密度马尾松人工林土壤理化特性差异显著(P<0.05).除全K、速效K和速效P外,土壤表层(0～20 cm)养分含量与林下灌木层物种多样性指数变化趋势一致.不同密度林地速效K和速效P含量变化波动较大.密度为2100 株·hm^-2的林分土壤 全P含量较高.中密度(1800 株·hm^-2)林地的土壤持水量和孔隙度均较高,土壤容重较低.     

Interpretation of scale in paired quadrat variance methods

Question: Previous interpretations of the variance plot of paired quadrat variance method (PQV) have been incomplete. The objective of this study was to clarify the interpretation of PQV, and to shed additional light on how different quadrat variance methods can be used, in concert, to measure scale in transect data. Methods: We used artificial and real data to examine how the PQVmethod elucidates spatial pattern. Two‐term local quadrat variance (TTLQV) and new local variance (NLV) methods, together with their three‐term counterparts, were also applied to the same data sets, and the results from all methods were compared. Results: When the mean gap size equalled the mean patch size along a transect, the first peak of the variance of PQV, NLV and TTLQV corresponded with the gap size (or patch size). However, if the mean gap size and patch size were unequal, the variance plot of PQV displayed a flat‐topped plateau, in which the first inflection represented the mean size of the smaller phase and the second inflection represented the mean size of the larger phase; TTLQV showed a clear peak and NLV displayed a distinct first peak while the second inflection was dampened. The results also indicated than the three‐term versions of quadrat variance methods did not consistently outperform their two‐term counterparts, and often confused the interpretation of scale. Conclusions: The quadrat variance methods associated with the patch‐gap measurements were able to efficiently detect not only the size of patches, but also the size of gaps.     

海南三亚鹿回头造礁石珊瑚生长变化与人类活动的影响

采用全球珊瑚礁监测网络(GCRMN)推荐的永久样方法首次在国内开展珊瑚礁生长的监测和研究。在海南三亚鹿回头岸礁区建立了10个珊瑚礁永久样方,分别于2003年12月、2004年4月、2004年9月和2005年4月开展了4次造礁石珊瑚生长的现场监测,并对周边人类活动进行了相关调查。研究发现,鹿回头东北部岸礁区4个样方的珊瑚覆盖率稳定增长,珊瑚生长良好,监测期间的珊瑚生长覆盖率平均为3.1%,珊瑚死亡覆盖率平均为1.3%;中部和南部岸礁区5个样方的珊瑚覆盖率明显下降,珊瑚出现衰退,衰退范围有明显扩大,珊瑚生长覆盖率平均为2.2%,珊瑚死亡覆盖率平均达到7.9%。珊瑚新个体的繁殖数量极少,平均新生珊瑚数量近1个/m2,新生珊瑚覆盖率对珊瑚生长覆盖率的贡献较低。人类活动对鹿回头岸礁区珊瑚生长的影响主要有两类:一是捕捞、炸鱼、船只抛锚、潜水等物理破坏;二是沿岸养殖场和旅游餐馆污水排放产生的水质污染,导致珊瑚生长机理的破坏。其中,水质污染是造成中部和南部岸礁区样方珊瑚死亡的主要原因,与沿岸养殖场和餐馆的分布、排污时间以及排污量有密切关系。     

样地尺度现代表土花粉与植物群落的定量关系

建立现代植被与表土花粉的精确关系,是基于孢粉记录定量重建古植被与古气候的基础与关键.截止目前,植物群落样方记录较少参与到现代植被与花粉的统计分析中,限制了其精确关系的定量表达.本文通过中国东北样带的森林、草甸草原、典型草原和荒漠草原33个表土样品分析及植被样方调查,基于Bray-Curtis相异系数,研究了东北样带现代...     

Quartered neighbor method: A new distance method for density estimation

Quantitative data are essential to an appro-priate characterization of vegetation. In the past few years, considerable attention has been paid to vegetation sampling techniques. A number of methods have been developed for plant density estimations that utilize spacing distances instead of fixed-area quadrats. In this paper, we review the main distance methods for estimating density and propose a new distance method denominated the quartered neighbor method. In this method, the sampling point is considered the center, and the area around it is divided into four quadrants. The distance from the closest individual in each quadrant to its closest neighbor in the same quadrant is measured, and the average of them is the distance we need. It is actually an integration of two old distance methods, the nearest neighbor method, and the point-centered quarter method. With our new method and an old distance method (the point-centered quarter method), we calculated the average spacing distances of the Larix principis-rupprechtii population in the larch forests of the Donglingshan Mountain. Comparing the two methods with the quadrat method, we found they were almost the same in accuracy, but the precision of the new one was better. Meanwhile, it is adequate in sampling intensity and adaptable for general use in rapid ecological survey work.     

Nest density and distribution of subterranean ants in an evergreen broadleaf forest in Japan with special reference to Amblyopone silvestrii

The density and distributions of nests of the subterranean ants were studied by excavation of thirty 1‐m² quadrats in an evergreen broadleaf forest in central Japan. A total of 20 ant species were collected and the densities of Amblyopone silvestrii and Paratrechina flavipes were highest (both 0.83 nests/m²). The distribution patterns were analyzed by the Standardized Morisita Index (I_p) for the five species that had mean densities of more than 0.5 nests/m². Of them, A. silvestrii and Hypoponera sauteri showed random distributions, while nests of Paratrechina flavipes were significantly overdispersed and those of Carebara yamatonis and Myrmecina nipponica were weakly clumped. These distributional patterns were discussed in connection with the ecology of the ants. In particular, the social organization of A. silvestrii was investigated based on the distributional pattern and the composition of collected colonies.     

Ant Diversity in Dominant Vegetation Types of Southern Cameroon

Ants have been shown as particularly affected by land disturbance through deforestation and conversion of forest to agriculture. The effect of land use change on ant diversity in the Congo Basin is not well known. We conducted intensive sampling along a gradient of increasing vegetation disturbance to test the effect of habitat disturbance on ant diversity and Functional Groups composition. Sampling was conducted in 30 plots (5 study sites × 3 habitat × 2 plots/habitat), replicated six times in 1 year. In each plot, ants were monitored with pitfall traps, quadrats and baits. We recorded 237 ant morphospecies grouped in 10 subfamilies and 43 genera. Myrmicaria opaciventris was the most abundant species followed by Anoplolepis tenella. Forest had greater ant diversity compared with fallows and mixed‐crop fields. Functional groups were dominated by Opportunists, followed by Omnivorous Arboreal Dominants and Generalized Mymicinae. Their composition was not affected by the disturbance, but occurrence of Specialist Predators decreased with increasing disturbance. Occurrence of Generalized Myrmicinae, Opportunists and Subordinate Camponotini increased with disturbance. These results indicate that forest conversion into mixed‐crop fields reduce ant diversity. It can also increase abundance of species with generalized diet that predominates where stress and disturbance limits other ants.     

Sequential sampling for adult coccinellids in wheat

Adult aphidophagous coccinellids are important predators of cereal aphids in wheat in the Great Plains of the United States for which sampling methods are needed to facilitate improved management. An equation relating the mean number of adult coccinellids per m² in a wheat field to its variance was obtained using Taylor's power law. A sequential sampling procedure was developed to estimate the number of adult coccinellids per m² with constant average statistical precision (standard error/mean). The procedure was constructed by an equation relating the number of adult coccinellids per m² to the number of adult coccinellids per minute of counting incorporating into the Taylor's power law relationship. The procedure involves conducting a series of 1-min counts while walking through a field at a constant velocity of 10 m per minute. After each 1-min count sequential sampling stop-lines are consulted to determine if the specified level of precision has been achieved. Two methods, a statistical procedure and comparison with independent data, were used to assess the consistency with which the specified level of precision was achieved by the procedure. Results indicated that observed precision was close to that specified by the user over a wide range of adult coccinellid density.     

A method to optimize precision and scale in grassland monitoring

Abstract. Methods for monitoring and survey of plant species abundance which do not account for variation in scale are often insensitive and imprecise. In monitoring, repeated observations are usually made within a fixed unit. Counts of species' presence must be made in a range of subunit sizes to accommodate the range of scales at which different species occur. A method comprising a rectangular fixed unit containing an 8 × 4 grid of square subunits has been developed and tested. Each subunit comprises a series of nested cells of increasing size, within which species are recorded cumulatively. Using this method, the concept of optimum scale is introduced. The optimum scale for a species is that for which its frequency count is closest to the midpoint. Two characteristics, sensitivity (absolute change detected) and blindness (failure to detect change in a species) were calculated for 24 plots from lowland grazing marsh which had been partially flooded between the time of two surveys. Optimum scale had greater sensitivity and lower blindness than any single scale in the majority of plots. Combining sensitivity and blindness, optimum scale was always superior. For the whole sample, optimum scale was less likely to cause Type I or Type II errors. The method is recommended for monitoring grasslands and allied plant communities in large geographical areas.     

山西省草兔的一些生态资料

山西省草兔的一些生态资料卢欣，申守义，高尚文（山西省生物研究所太原０３０００６）关键词草兔，粪便样方，益害分析，天敌和寄生虫草兔（Ｌｅｐｕｓｃａｐｅｎｓｉｓ）是我国最重要的小型狩猎动物之一，但其生态仅有零星报道［１，２］。１９８７－１９９２年，我们在...     

Branching-diffusion model for the formation of distributional patterns in populations

A continuous time branching-diffusion process model is presented to describe the development of spatial distributional patterns of a biological population. In the model each unit moves independently following diffusion processes on a plane, and multiplies or goes extinct at random times. Standard methods for measuring the degree of aggregation used in field ecology are applied to this model population. Kuno's C _Aindex using quadrat sampling is calculated, and the dependence of the index on time, quadrat size, initial density, and diffusion and branching rules, is discussed. Pielou's index based on distance measurement is evaluated by the solution of a nonlinear partial differential equation. Both methods show that continuous-time branching-diffusion processes produce a contagious spatial pattern; as in a discrete-time model studied by Iwasa and Teramoto (1977).