长江三峡库区物种多样性的垂直分布格局:气候、几何限制、面积及地形异质性的影响

为了验证生物多样性地理格局的几个重要假说,即种-面积关系、水分-能量动态假说、几何限制(中域效应)假说和生境异质性假说,作者以长江三峡库区维管植物物种丰富度沿海拔梯度的分布格局为例,采用多元回归和方差分解方法,研究了面积、气候、几何限制、地形异质性对多样性垂直格局的独立影响和协同作用,及其对各植物类群(不同分布宽度、不同分布区类型和不同生长型)影响的差异.结果表明,三峡库区各种植物类群的物种丰富度随着海拔上升均呈先升后降的单峰格局.水分-能量动态假说对多样性格局有很强的解释能力,其总的解释力(＞93％)明显高于其他所有解释机制.但对于很多植物类群而言,水分和能量的解释力中有很大一部分属于几何限制、面积及地形异质性等因素的协同作用.几何限制对分布宽度大的物种的多样性格局解释力很强,但对分布宽度小的物种作用很小;面积自身对物种丰富度解释力较强,但在考虑了其他环境因素的影响时,仅对少数植物类群有解释力;地形异质性自身对多样性的解释能力很弱,但在多元回归模型中起着必要的作用.综合来看,水分-能量动态是解释三峡库区植物多样性垂直格局的最重要的机制.几何限制的作用随着物种分布宽度减小而递减;地形异质性虽然对多样性垂直格局的影响较弱,但也是一种必要的补充解释机制;由于面积与气候、几何限制等因素存在强烈的共线性,面积对植物多样性垂直格局的相对作用大小还需要进一步的系统比较研究.     

白水江自然保护区两栖、爬行动物物种丰富度的海拔梯度格局的解释:水分能量动态假设和生境异质性假设

采用线性回归模型和方差分离方法,利用水分能量动态假设和栖息地异质性假设解释了白水江自然保护区两栖、爬行动物物种丰富度的海拔分布格局。水分能量动态假设对白水江自然保护区两栖爬行动物物种丰富度的海拔分布格局的解释力较强,同时,水分能量动态假设和栖息地异质性假设之间存在着较强的共线性。年均降水量(PAN)进入了两栖动物物种丰富度海拔分布格局的最优线性回归模型,未进入爬行动物物种丰富度海拔分布格局的最优线性回归模型,但潜在蒸散量(PET)及其二次方(PET2)全部进入了爬行动物的最优线性回归模型,说明水分对两栖动物的重要性和温度对爬行动物的重要性。方差分离结果表明,栖息地异质性假设对两栖、爬行动物物种丰富度海拔分布格局的独立解释力较低,而水分能量动态假设的独立解释力较高。对于广域种,可能受到边界限制的影响,水分能量动态假设和栖息地异质性的解释力并不高。     

秦岭两栖、爬行动物物种多样性海拔分布格局及其解释

物种多样性和种域宽度沿环境梯度的分布格局及其成因机制一直是生物地理学和生态学讨论的重要议题。本研究采用多元回归模型和方差分离的方法判断面积、水分和能量、边界限制对秦岭两栖、爬行动物及其不同区系成分的物种丰富度海拔梯度分布格局的影响。结果表明, 秦岭两栖爬行动物及其不同区系成分的物种丰富度均呈单峰分布格局, 但峰值分布的海拔段有所差异。形成这种格局是各种因素相互作用的结果, 3种假设的独立解释力较低。水分能量动态假设对两栖、爬行动物物种的丰富度格局有很强的解释能力, 但水分和能量的解释力中有很大一部分属于边界限制、面积的协同作用, 在解释两栖动物的海拔分布格局时, 边界限制与水分和能量之间存在较强的共线性, 而在解释爬行动物的海拔分布格局时, 面积与水分和能量之间存在较强的共线性。同时, 本研究采用Stevens法和逐种法对Rapoport法则进行了验证。结果表明, 爬行动物物种种域的海拔梯度格局基本上支持Rapoport法则, 两栖动物很难判断是否支持Rapoport法则。     

西双版纳种子植物物种多样性的垂直格局及机制

物种多样性海拔分布格局及其形成机制的研究是生物地理学和宏观生态学的重要议题之一。本文利用西双版纳植物专著资料, 结合高分辨率的地形和气候等数据, 探讨了面积、边界限制和现代气候对西双版纳野生种子植物物种丰富度及物种密度海拔分布格局的影响。结果表明: (1)物种丰富度呈单峰分布格局, 面积(81.9%)、边界限制(17.5%)和气候(60.0-69.3%)都不同程度地解释了物种丰富度的单峰格局; (2)利用幂函数种-面积关系计算的物种密度沿海拔大致呈减小的分布趋势, 气候的解释率降低为32.6-40.6%, 与边界限制无显著相关关系; (3)利用等面积高度带划分得到的物种密度沿海拔呈单峰变化趋势, 物种密度与边界限制无显著相关性, 但气候对物种密度的解释率为81.6-89.9%。研究结果有助于准确全面地理解物种多样性的海拔分布格局及其成因机制, 为西双版纳生物多样性保护提供理论支撑和实践指导。     

秦岭牛背梁植物物种多样性垂直分布格局

基于秦岭山脉中段牛背梁自然保护区南北坡垂直样带51个样方的调查资料,利用植被数量分析方法(TWINSPAN和DCA)对牛背梁植物群落进行了分类和排序,并分析了植物物种多样性沿海拔梯度的分布格局。结果表明,牛背梁的植被群落具有明显的海拔梯度格局,从低海拔到高海拔依次分布有：锐齿槲栎(Quercus aliena var.acuteserrata)林,桦木(Betula spp.)林．巴山冷杉(Abis Jargesii)林和亚高山灌丛。海拔梯度是牛背梁山区制约植物群落分布的主要因子,而坡向和坡度则起到次要作用。对物种多样性的分析表明,物种总数、木本植物物种多样性和草本植物物种多样性在南北坡具有不同的海拔梯度格局。物种总数在南坡呈现单峰分布格局,而在北坡分布趋势不明显;木本植物物种多样性在南北坡具有相似的分布格局：在低海拔沿海拔梯度变化不明显,而在高海拔则随海拔上升而急剧下降;草本植物物种多样性在南北坡沿海拔梯度变化的规律不明显。β多样性沿海拔梯度先减少后增加,形成两端高中间低的格局,说明中海拔地区生境条件较为均一,低海拔地区的人为活动增加了生境的异质性,而高海拔地区的生态过渡特性增加了物种的更替速率以及群落的相异性。     

面积和中间膨胀效应对丽江地区种子植物物种丰富度垂直分布格局的影响

滇西北地区是我国三大特有物种分化中心之一。作者利用地方植物志资料,结合数值高程模型(DEM)数据,研究了云南丽江地区种子植物物种丰富度的垂直分布格局,并分析了面积和中间膨胀效应(mid-domaineffect)对该格局的影响。研究结果表明:随着海拔的升高,各海拔段面积呈先增加后下降的分布格局;物种丰富度、物种密度和中间膨胀效应的物种丰富度预测值在海拔梯度上均呈单峰型变化格局。面积和中间膨胀效应对丽江地区物种丰富度的垂直分布格局有着显著的影响。其中,面积起主要作用,对物种丰富度的变异解释百分率达80.2%,而中间膨胀效应的影响作用相对较小,仅占11.3%。     

高黎贡山种子植物物种丰富度沿海拔梯度的变化

物种丰富度沿海拔梯度的分布格局成为生物多样性研究的热点。为探讨中尺度区域物种丰富度沿海拔梯度的分布,本文以高黎贡山为研究对象,利用该地区的地方植物志资料,结合通过GIS生成的区域数字高程模型(DEM)数据,分析了该区域全部种子植物和乔木、灌木、草本三种生活型种子植物物种丰富度的垂直分布格局以及物种密度沿海拔梯度的变化特征。结果表明：(1)全部种子植物和不同生活型植物物种丰富度随着海拔的升高呈现先增加后减小的趋势,最大值出现在海拔1500—2000m的范围;(2)物种密度与海拔也呈现单峰曲线关系;(3)物种丰富度和物种密度分布格局的形成主要受海拔所反映的水、热状况组合以及物种分布的边界影响。     

南岭国家级自然保护区兰科植物物种多样性的海拔梯度格局

兰科是单子叶植物最大的科和被子植物中的第二大科.兰科植物物种多样性的海拔梯度格局因地域或坡向不同而呈不同趋势.南岭国家级自然保护区地处南岭山脉中段南坡,植物资源丰富.作者对南岭国家级自然保护区兰科植物进行了为期4年的调查,记录了其种类、数量、生活型、海拔、生境,分析了其区系成分,并依据IUCN(2001)濒危物种红色名录及保护区的具体情况对其濒危等级进行了评估.从海拔230-1,902m,每200 m分段,共划分为9个海拔段分析其垂直分布格局.结果显示:(1)实地记录兰科植物38属70种,大多数种类数量较少,乳阳管理处的种类最为丰富;(2)随着海拔的上升,总体兰科植物以及不同生活型的兰科植物物种数量均呈现"中间高度膨胀型"而峰值偏向低海拔的特点;(3)濒危物种主要集中在600-1,000 m人为活动稀少、环境好的小生境中;(4)800-1,000 m的区系成分最丰富,热带性质的兰花多数分布在海拔1,600 m以下;(5)相邻海拔段的兰科植物种类的相似性系数较高;海拔段相隔越远,相似性系数越小.小生境和水分条件对于兰科植物的生长非常重要,中海拔具有良好的水热条件,因此物种多样性最高;而低海拔地区的人为破坏使得该海拔段兰科植物物种的多样性显著降低.     

甘肃白水江国家级自然保护区珍稀植物的垂直分布及其保护

白水江自然保护区有各类珍稀濒危植物104种,占该区总种数的5.28%。其中划归《国家重点保护野生植物名录(第一批)》的有20种,划归《中国珍稀濒危保护植物名录》的有37种,划归《国家珍贵树种名录》的有18种。该区在整个海拔梯度上均有珍稀植物分布,但很不均匀。根据珍稀植物物种丰富度的高低,大体可分为“极丰富段”“较丰富段”“丰富段”“稀少段”4段。不同类型的珍稀植物的垂直分布也有差异。根据白水江珍稀濒危植物的垂直分布格局和保护现状提出了几点建议。     

广东象头山国家级自然保护区兰科植物垂直分布格局

于2019～2022年对广东象头山国家级自然保护区内的兰科植物进行专项调查,记录兰科植物种类、数量、生活型、海拔、生境等信息,分析保护区内兰科植物的垂直分布格局,并根据《广东高等植物红色名录》和《国家重点保护野生植物名录》对各海拔高度兰花濒危等级的物种数量进行统计。结果显示：(1) 实地记录兰科植物33属48种,多数种类种群数量较少;(2) 随着海拔上升,各海拔梯度的兰科植物总种数和不同生活型的种数均呈现“中间高度膨胀型”分布特点,峰值在中低海拔区域;(3) 濒危物种主要集中在海拔200～500 m区间;(4) 相邻海拔段的兰科植物种类相似性系数较高,垂直梯度差异越大,相似性系数越小。低海拔地区可能由于人为干扰频繁,兰科植物物种多样性较低;中海拔物种多样性最丰富;高海拔地区生长环境较苛刻,物种数量较少。     

Altitudinal patterns of plant species richness on the Baekdudaegan Mountains, South Korea: mid-domain effect, area, climate, and Rapoport’s rule

We studied the altitudinal patterns of plant species richness and examined the effects of geometric constraints, area, and climatic factors on the observed richness patterns along the ridge of the Baekdudaegan Mountains, South Korea. Rapoport’s altitudinal rule was evaluated by examining the relationship between altitudinal range size and midpoint. We also examined the latitudinal effect on species richness. Plant data were collected from 1,100 plots along a 200–1,900 m altitudinal gradient along the ridge of the Baekdudaegan. A total of 802 plant species from 97 families and 342 genera were found. The altitudinal patterns of plant species richness along the ridge of the Baekdudaegan depicted distinctly hump-shaped patterns, although the absolute altitudes of the richness peaks vary somewhat among plant groups. While the mid-domain effect (MDE) was the most powerful explanatory variable in simple regression models, species richness was also associated with climatic factors, especially mean annual precipitation (MAP) and temperature (MAT) in multiple regression models. The relative importance of the MDE and climatic factors were different among plant groups. The MDE was more important for woody plants and for large-ranged species, whereas climatic factors were better predictors for total and herbaceous plants and for small-ranged species. Rapoport’s altitudinal rule and a latitudinal effect on species richness were not supported. Our study suggests that a combined interaction of the MDE and climatic factors influences species richness patterns along the altitudinal gradient of the Baekdudaegan Mountains, South Korea.     

秦岭小陇山保护区维管植物丰富度和种域海拔梯度格局及其对Rapoport法则验证

物种丰富度和种域的海拔梯度格局及其形成机制一直是生物地理学和生物多样性研究的重点.海拔Rapoport法则认为,物种丰富度随海拔升高而逐渐降低,种域逐渐变宽.本文分析了秦岭小陇山国家级自然保护区维管植物物种丰富度及其种域宽度的海拔梯度格局;采用4种常用方法,验证不同类群、不同生长型和不同阶元的物种丰富度与其分布中点间的关系,并检验其是否支持海拔Rapoport法则.结果表明: 除窄域种外,秦岭小陇山维管植物物种丰富度随海拔升高呈先升后降的单峰分布格局;狭域种主要分布在低海拔和高海拔段,低海拔段的丰富度高于高海拔段;物种海拔分布宽度与海拔关系因不同类群和验证方法而异,随分类阶元的增大更容易支持Rapoport法则,这可能与不同分类阶元所占据的生态位不同有关;被子植物的平均种域呈单峰分布格局,蕨类植物和裸子植物的种域海拔梯度格局无明显规律;藤本植物平均种域随海拔升高而变宽,灌木能适应不同的环境条件,因此,灌木分布对海拔梯度的变化不敏感.Pagel验证方法最容易支持Rapoport法则,Stevens方法次之,中点法受中域效应的影响物种平均种域分布呈单峰分布格局而不支持Rapoport法则,逐种法受散点图分布格局的影响线性模型拟合结果解释力很低.
     

Altitudinal patterns of seed plant richness in the Gaoligong Mountains, south-east Tibet, China

Elevational patterns of species richness and their underlying mechanisms have long been a controversial issue in biodiversity and biogeographical research, and several hypotheses have been proposed in the past decades. Local and regional studies have suggested that area and geometric constraint are two of major factors affecting the elevational pattern of species richness. In this study, using data of seed plants and their distribution ranges and a Digital Elevation Model data set, we explored altitudinal patterns of seed plant richness and quantified the effects of area and the mid-domain effect (MDE) on the richness patterns in a high mountain area, Gaoligong Mountains (ranging from 215 m to 5791 m a.s.l.) located in south-eastern Tibet, China. The results showed that richness and density (richness/log-transformed area) of seed plants at species, genus, and family levels all showed hump-shaped patterns along the altitudinal gradient. The altitudinal changes in richness of species with three different range sizes (< 500 m, 500–1500 m, and > 1500 m), species of different plant life-forms (trees, shrubs, and herbs), and endemic species further confirmed this finding. Analysis of Generalized Linear Model depicted that although the area of each elevational band was always in high correlation with the species richness, the MDE could explain 84.9%, 33.8%, 83.8%, and 84.5% of the total variation in richness for all species and the three species groups with different range sizes, respectively. This suggests that the MDE significantly influences the patterns of species richness and is likely be stronger for broad-ranged species than for narrow-ranged ones in the Gaoligong Mountains.     

Climate stability is more important than water–energy variables in shaping the elevational variation in species richness

Changes in climate variables have an important impact on the prediction and protection of elevational biodiversity. Gaps exist in our understanding of the elevational distribution patterns in seed plant species richness. Our study examines the importance of climate variables in shaping the elevational variation in species richness. The importance of boundary constraint was also taken into account. Model selection based on Akaike's information criterion was used to select the best explaining climate models. Variation partitioning was used to assess the independent and joint effects of water–energy, physiological tolerance, and environmental stability variables on species richness. Our results revealed that: (a) Both raw (boundary constraint unreduced) and estimated (boundary constraint reduced) species richness showed large elevational variation, with the peak species richness seen at midelevations. The environmental variables were better at explaining the distribution pattern of species richness along the elevation, when the effect of boundary constraint was reduced; (b) the physiological tolerance and environmental stability variables explained more variation in raw and estimated species richness compared with the water–energy variables. Estimated species richness was better explained (98.6%) by the environmental variables than raw species richness (94%); (c) the water‐related variables generally had the highest independent effect on raw and estimated species richness and were dominant in shaping the elevational variation in species richness. Our findings quantify the influence of boundary constraint on the distribution pattern of species along an altitudinal gradient and compare the relative contributions of environmental stability and water–energy in explaining the altitude gradient distribution pattern of plant seed species.     

Patterns of diversity, altitudinal range and body size among freshwater fishes in the Yangtze River basin, China

Aim To document patterns in diversity, altitudinal range and body size of freshwater fishes along an elevational gradient in the Yangtze River basin. Location The Yangtze River basin, China. Methods We used published data to compile the distribution, altitudinal range and body size of freshwater fishes. Correlation, regression, clustering and graphical analyses were used to explore patterns in diversity, altitudinal range and body size of freshwater fishes in 100‐m elevation zones from 0 to 5200 m. Results Species richness patterns across the elevational gradient for total, non‐endemic and endemic fishes were different. The ratio of endemics to total richness peaked at mid elevation. Land area on a 500‐m interval scale explained a significant amount of the variation in species richness. Species density displayed two peaks at mid‐elevation zones. The cluster analysis revealed five distinct assemblages across the elevation gradient. The relationship between elevational range size and the midpoint of the elevational range revealed a triangular distribution. The frequency distribution of log maximum standard length data displayed an atypical right‐skewed pattern. Intermediate body sizes occurred across the greatest range of elevation while small and large body sizes possessed only small elevational amplitudes. The size‐elevation relationship between the two major families revealed a very strong pattern of body size constraint among the Cobitidae with no corresponding elevational constraint and a lot of body size and elevational diversification among the Cyprinidae. Main conclusion The data failed to support either Rapoport's rule or Bergmann's rule.     

内蒙古昆虫物种多样性分布格局及其机制

物种多样性的地理分布格局及其机制是宏生态学和生物地理学的核心问题之一。区域尺度与局域尺度的影响因素, 如温度、降水、海拔变化、生境过滤、捕食、竞争与互惠等, 共同影响昆虫物种多样性的分布格局。然而, 迄今为止少有研究同时讨论不同尺度驱动因子对昆虫多样性地理分布格局的影响。本文基于内蒙古自治区86个旗县的昆虫多样性数据, 结合各地年平均气温、年降水量、古气候变化、海拔变化及植物多样性, 探讨昆虫物种多样性分布格局及其主要驱动因子。结果发现内蒙古昆虫多样性主要受到植物多样性与海拔变化的影响, 而气候因子对昆虫物种多样性的影响并不大。这一结果表明种间关系(食物多样性)与生境异质性可能对内蒙古昆虫多样性的分布格局起着主导作用。     

泰山南北坡植物物种多样性垂直梯度格局的比较

以泰山南北坡14块样方的调查资料为基础,分析了泰山植物物种多样性沿海拔梯度的分布格局。结果表明:在相同海拔范围内,南坡物种丰富度大于北坡,泰山物种丰富度随海拔的升高而减少。整个群落及不同层次的物种多样性沿海拔梯度在泰山南北坡呈现不同的分布格局。在人为干扰程度低的情况下,北坡的群落物种丰富度在各个层次均较高,而多样性指数在各个层次不一样,北坡乔木层的多样性指数较南坡低,但灌木层和草本层则是北坡明显大于南坡。整体上,物种多样性指数与海拔的相关性,北坡要比南坡好。     

Plant species and growth form richness along altitudinal gradients in the southwest Ethiopian highlands

Questions: Do growth forms and vascular plant richness follow similar patterns along an altitudinal gradient? What are the driving mechanisms that structure richness patterns at the landscape scale? Location: Southwest Ethiopian highlands. Methods: Floristic and environmental data were collected from 74 plots, each covering 400 m². The plots were distributed along altitudinal gradients. Boosted regression trees were used to derive the patterns of richness distribution along altitudinal gradients. Results: Total vascular plant richness did not show any strong response to altitude. Contrasting patterns of richness were observed for several growth forms. Woody, graminoid and climber species richness showed a unimodal structure. However, each of these morphological groups had a peak of richness at different altitudes: graminoid species attained maximum importance at a lower elevations, followed by climbers and finally woody species at higher elevations. Fern species richness increased monotonically towards higher altitudes, but herbaceous richness had a dented structure at mid‐altitudes. Soil sand fraction, silt, slope and organic matter were found to contribute a considerable amount of the predicted variance of richness for total vascular plants and growth forms. Main Conclusions: Hump‐shaped species richness patterns were observed for several growth forms. A mid‐altitudinal richness peak was the result of a combination of climate‐related water–energy dynamics, species–area relationships and local environmental factors, which have direct effects on plant physiological performance. However, altitude represents the composite gradient of several environmental variables that were interrelated. Thus, considering multiple gradients would provide a better picture of richness and the potential mechanisms responsible for the distribution of biodiversity in high‐mountain regions of the tropics.     

Modelling of plant species richness along altitudinal gradient: Asalem Watershed basin,temperate deciduous forests in northern Iran

Among the various topographical factors, effects of altitudinal factor on species diversity, richness, composition and biological functions patterns are considerable. This study was done to investigate plant species richness along altitudinal gradient in the Asalem watershed basin, northern forests of Iran. For these purpose, 13 altitudinal transects were established from 100 to 2500 m, according to altitude ranges within 200 m intervals. Data collection was done in 216 circular plots of 1000-m² area with a distance of 150 m from each other. In total, 576species of 325 genus and 96 families were recorded. The highest number of species was belonged to Asteracese، Fabaceae and Lamiaceae families. The results indicated that forbs with 414 species belong to54 families and ferns with 31 species belong to10 families were the largest and smallest group of plants in study area respectively. In herbaceous layer, the mean number of species was increased along altitudinal gradients (P ≤ 0.005). The lowest and highest value of species number was belonged to 500 and 2500 m altitudes, respectively. Generally, there was a gradual decline of species number at 100 to 500 m. Fitted models indicated that variation patterns at altitudinal gradients were significant and the proposed polynomial model had a high conformity with changes of species richness. The lowest value of species number in woody layer was belonged to 1900 m altitude and 2100 m had the highest value. Three peak points were recorded at the beginning, middle and the end of gradient, respectively. Sinusoidal models showed a correlation between species richness and altitudinal changes by high coefficient of determination. Results of β –diversity indicated that species change rate was fixed at 700 m altitude, but it was decreased by increasing altitude. Fluctuations of β diversity were followed of the sinusoidal models. In the study area, destructive factors including road construction, tourism and over-exploitation are a serious threat for the ecosystem and this study can be considerable to develop targeted strategies for conservation of plant diversity. In addition, study of habitat conditions in each altitudinal gradients is necessary to reconstruction stands with low species diversity and appropriate species selection to establish stands with high density.     

Phytogeographical evidence for post‐glacial dispersal limitation of European beech forest species

The post‐glacial migration of European beech Fagus sylvatica has been addressed by many studies using either genetic or fossil data or a combination of both. In contrast to this, only little is known about the migration history of beech forest understorey species. In a review of phytosociological literature, we identified 110 plant species which are closely associated with beech forest. We divided the distribution range of European beech forests into 40 geographical regions, and the presence or absence of each species was recorded for each region. We compared overall species numbers per region and numbers of narrow‐range species (species present in <10 regions). A multiple regression model was used to test for the explanatory value of three potential diversity controls: range in elevation, soil type diversity, and distance to the nearest potential refuge area. A hierarchical cluster analysis of the narrow‐range species was performed. The frequency of range sizes shows a U‐shaped distribution, with 42 species occurring in <10 regions. The highest number of beech forest species is found in the southern Alps and adjacent regions, and species numbers decrease with increasing distance from these regions. With only narrow‐range species taken into consideration, secondary maxima are found in Spain, the southern Apennines, the Carpathians, and Greece. Distance to the nearest potential refuge area is the strongest predictor of beech forest species richness, while altitudinal range and soil type diversity had little or no predictive value. The clusters of narrow‐range species are in good concordance with the glacial refuge areas of beech and other temperate tree species as estimated in recent studies. These findings support the hypothesis that the distribution of many beech forest species is limited by post‐glacial dispersal rather than by their environmental requirements.