古尔班通古特沙漠固定沙丘上白梭梭和梭梭的空间分布及种间关联性

为了探讨沙漠中固沙灌木种群共存和演替机制, 本文基于古尔班通古特沙漠东南缘固定沙丘上白梭梭(Haloxylon persicum)和梭梭(H. ammodendron)种群的地理位置和生长发育阶段信息(幼株、营养株、生殖株和死株), 采用点格局分析方法(g(r)函数)及Monte-Carlo随机模拟检验和零模型选取的方法, 分析了固沙灌木白梭梭和梭梭种群不同生长发育阶段在0-20 m尺度内的空间分布格局及种间关联性。结果表明: (1)两个种群在研究尺度范围内呈聚集分布, 随着尺度的增大, 其聚集强度逐渐减弱; (2)两个种群整体上呈负关联关系, 尺度越大负关联关系越显著; (3)白梭梭种群生长发育阶段相差越大, 个体间正关联关系越显著; 梭梭种群生长发育阶段越接近, 个体间正关联关系越显著; (4)两个种群中龄级较大的个体(如营养株、生殖株和死株)会对对方种群中龄级较小的幼株产生一定的抑制作用; 同时, 随着两个种群中个体的成长, 双方受到的抑制作用逐渐减弱, 主要表现为正关联和无关联。总体而言, 古尔班通古特沙漠固定沙丘白梭梭和梭梭种群的分布格局整体上为聚集分布, 随龄级增加聚集性减弱, 受生境异质性和扩散限制的影响明显。种间关系多为负相关, 种内不同生长发育阶段之间均为正关联关系。     

长白山落叶阔叶混交林的物种多样性、种群空间分布格局及种间关联性研究

根据在吉林省蚊河实验管理局1hm^2落叶阔叶混交林样地调查结果,对落叶阔叶混交林的群落结构、物种多样性、主要树种的空间分布格局以及树木种群的种间关联进行了研究．结果表明,树木种群优势程度不明显;乔木、灌木、草本的均匀度指数、生态优势度指数都较低．对5个主要乔木种群的空间格局均呈现聚集分布;15个主要树种之间有14个种对存在着显著的种间关联,一个种独立;树种之间正关联的种对少,关联强度低,而负关联多且较高,群落结构组成不稳定,处于软阔叶林向硬阔叶林直至红松阔叶林过渡的阶段．     

长白山落叶阔叶混交林的物种多样性、种群空间分布格局及种间关联性研究

根据在吉林省蛟河实验管理局1 hm²落叶阔叶混交林样地调查结果,对落叶阔叶混交林的群落结构、物种多样性、主要树种的空间分布格局以及树木种群的种间关联进行了研究.结果表明,树木种群优势程度不明显;乔木、灌木、草本的均匀度指数、生态优势度指数都较低.对5个主要乔木种群的空间格局均呈现聚集分布;15个主要树种之间有14个种对存在着显著的种间关联,一个种独立;树种之间正关联的种对少,关联强度低,而负关联多且较高,群落结构组成不稳定,处于软阔叶林向硬阔叶林直至红松阔叶林过渡的阶段.     

杉木与米老排人工混交林群落木本植物空间格局研究

该研究在全面踏查广西大青山实验场杉木-米老排人工混交林群落的基础上,采用典型样方法选择1块90 m×110 m的永久固定样地,测量每株活立木中心位置坐标,检尺每株活立木胸径(地径)、树高、冠幅等,并采用径级代替龄级和空间点格局分析方法的Ripley's L(r)函数,分析杉木-米老排人工混交林的种群动态以及群落内主要木本植物种群的空间分布格局和主要种群的种间关联,以探讨杉木-米老排人工混交林群落内物种间的相互作用以及保持种群稳定与演替规律,为亚热带人工混交林培育的树种选择、空间结构调整及抚育管理提供理论依据。结果表明:(1)样地内胸径≥1 cm的活立木共计49个树种、 3 361株,其中杉木、米老排、三桠苦、红椎、九节、对叶榕、水锦树7个树种重要值都在4%以上,占有较大优势,是林分的主要树种。(2)杉木-米老排人工混交林群落内所有活立木(DBH≥1 cm)在0～40 m的尺度上表现出聚集分布,其中:幼树(1 cm≤DBH5 cm)在0～40 m的尺度上的聚集程度较群落内所有活立木聚集程度高;小树(5 cm≤DBH10 cm)在0～5 m的尺度上呈现随机分布,在6～40 m尺度上的聚集程度较弱;大树(DBH≥10 cm)在小于5 m的尺度上表现出均匀分布,在5～40 m尺度上服从于随机分布。(3)群落内7个主要种群除米老排和红椎接近随机分布外,其他种群皆服从聚集分布,且随尺度增加聚集程度增强。(4)样地内大树与小树之间相互独立,而小树与幼树、大树与幼树之间在研究尺度范围内存在正关联关系。(5)研究区群落内主要种群(21个种对)之间以无关联和负关联为主,只存在少量种群(5个种对)之间呈正关联,表明广西大青山实验场杉木-米老排人工混交林群落结构的稳定性较弱,尚未达到群落演替的顶级阶段。     

鹞落坪国家级自然保护区吊罐井物种分布格局与种间关联的多尺度分析

为了探讨群落结构形成机制,采用点格局分析方法,对鹞落坪国家级自然保护区吊罐井核心区1hm2样地内36个优势物种在0~50m尺度上的空间分布格局和种间关联性进行了研究。结果显示,36个物种的空间分布格局在小尺度上主要呈聚集分布,在较大尺度上呈随机分布的物种比例最高;对36个物种种间关联性的分析发现,无关联类型是该样地物种间相互作用的主要表现形式,并且在10m尺度上无关联种对的比例最低,正相关和负相关的种对在所有尺度上的比例均未超过20%。群落结构的次生性、生境异质性和扩散限制性是导致该样地物种分布和种间关系格局的主要原因。本研究结果有助于了解物种共存的尺度依赖性特征及其形成机制。     

太白山巴山冷杉林主要树种与开花秦岭箭竹的空间点格局分析

采用单变量和双变量O-ring函数对太白山大熊猫栖息地巴山冷杉林主要树种的空间分布格局、种间关联性及其与林下开花箭竹的空间关联性进行了多尺度分析.结果表明: 巴山冷杉林中,巴山冷杉数量最多,但种群结构衰退,白桦种群相对年轻,种群结构稳定,红桦种群也呈衰退趋势;3个主要树种在小尺度上呈聚集分布,随尺度增加,逐渐表现为随机分布.3个树种的空间关联性主要表现在小尺度范围内,随尺度增加,空间分布格局逐渐表现为不关联;巴山冷杉和白桦与开花秦岭箭竹在大、中尺度内呈现正相关,而红桦与开花秦岭箭竹在大、中尺度上表现出负相关.大熊猫栖息地内乔木和林下秦岭箭竹共同推动森林的动态演替和发展,进而影响秦岭大熊猫栖息地的环境变化.     

荒漠内陆河岸胡杨和多枝柽柳幼苗种群空间分布格局及种间关联性

运用方差均值比率法、负二项参数、丛生指标、平均拥挤度、聚块性指数和扩散系数等7个指标以及双项轨迹方差法,研究了塔里木河中下游荒漠河岸植被建群种胡杨(Populus euphratica)和多枝柽柳(Tamarix ramosissima)幼苗种群的空间分布格局和种间关联性.结果表明,胡杨和多枝柽柳幼苗的空间分布呈显著的聚集分布,聚集规模大小为16 m2.利用2×2列联表χ2统计量、联结系数和共同出现百分率等测度方法,综合分析了2个种对联结性质和程度.结果表明,胡杨和多枝柽柳2个幼苗种群表现出强的正关联,这2种植物种群现处于稳定分布格局,种间共存,占有共同的生态位.     

干旱荒漠区人工植物群落演替模式及其生态学机制研究

以我国干旱荒漠区包兰铁路沙坡头地段人工植被防护林体系作为研究对象,研究了区域植被建立与发展过程中,优势植物种的种群动态和人工植物群落的演替模式,探讨了植物群落演替的内在动因和生态学机制．结果表明,该区人工植被经过40余年的演变,其植物种组成发生了很大的变化,已由原来的灌木、半灌木人工植物群落演变为一年生草本植物占优势的人工-天然荒漠植物群落．在此演替过程中,人工栽植的灌木种如柠条、花棒等的重要值不断减少,逐渐从人工植物群落中退出;而天然繁衍的一年生草本植物如小画眉草、雾冰藜、刺蓬、虎尾草等相继侵入,并逐渐成为该区的优势植物种;油蒿由于具有天然下种自行更新能力,在群落中始终占有重要地位．这种物种替代模式与该地区降水资源严重匮乏以及沙地表面结皮的增厚,致使沙子下层含水量降低。深根系的灌木及多年生草本的繁衍受到限制密不可分．     

湖北九宫山珍稀植物鹅掌楸群落结构与物种组成

为了解珍稀植物鹅掌楸(Liriodendron chiniense)种群结构特征,加强其就地保护,基于湖北九宫山国家级自然保护区建立的1 hm2长期监测样地,分析了鹅掌楸所在群落的物种组成、优势种的径级结构和空间分布格局、鹅掌楸的种内关联及其与群落优势种的种间关联.样地共有胸径≥1 cm的木本植物7159株,隶属于40...     

黑河上游高寒退化草地狼毒种群小尺度点格局分析

植被斑块化是自然界的一种普遍现象,斑块的形成和变化对植物种群格局的形成和变化具有重要影响。在黑河上游祁连山北坡高寒退化草地,采用点格局分析方法,研究了小尺度上狼毒(Stellera chamaejasme)种群的种群密度、组成格局以及分布格局。结果表明:随着狼毒种群分盖度的增大,种群密度、领地密度和组成格局呈现规律性的变化,斑块内部狼毒种群的数量出现增减交替变化趋势,组成格局规律明显;狼毒种群的分布格局表现出与尺度关联的变化趋势,在31%–40%分盖度下,狼毒种群在所有尺度上表现为随机分布,在41%–50%、51%–60%、61%–70%、71%–80%分盖度下随着尺度增大,分布格局的基本模式为:随机—聚集—随机或均匀—随机—聚集—随机分布,在聚集状态下,聚集强度不同。以成株为核心的斑块内部种群表现为随机分布或均匀分布,相对于外部表现为聚集分布,随着成株个体数量的逐渐增多,种群竞争关系由种间竞争转化为种内竞争,促进了斑块扩张与合并、斑块增多与吞并,从而实现了种群扩散。     

喀斯特次生林幼树更新空间分布格局及种间关联性

本研究以贵州省喀斯特典型区域紫云苗族布依族自治县撂荒30余年后自然恢复形成的次生林为对象,设置140 m×120 m固定样地,系统调查样地内幼树更新,并采用空间点格局分析方法分析幼树更新优势种群在不同空间尺度下的分布格局和种间关联性。结果表明: 调查样地中幼树共计1291株,包括39个树种,其中光皮桦、化香、马尾松、枫香和山杨5个树种的幼树个体数量总和达83.7%,重要值总和达77.8%,为幼树更新的优势树种。光皮桦、化香和枫香3个幼树优势种群的空间分布格局在0～60 m空间尺度上均呈现较强的聚集分布;马尾松和山杨2个幼树优势种群在小尺度上呈现聚集分布,大尺度上则随机分布。幼树优势种群空间关联性多呈现正关联,仅马尾松与枫香和山杨在小尺度呈现正关联,大尺度呈现不相关。调查样地5个幼树优势种群空间分布格局及种间关联性差别较大,可能与树种的生物学特性、生境及空间资源的利用密切相关。目前,林分多以先锋树种为主,群落结构不稳定;以马尾松和光皮桦为优势种群的松-桦混交林可能成为下一阶段演替方向,建议通过森林经营措施加快植被恢复进程。     

基于功能性状的毛乌素沙地不同演替阶段适生植物筛选

沙地生态系统修复是恢复生态学研究的热点问题,适生植物筛选是修复的关键。植物功能性状反映了植物在不同环境中的生存策略,探究沙地植物功能性状及其与环境之间的关系,有助于筛选用于植被恢复的物种,为保护沙地生态系统提供理论依据。以毛乌素沙地为研究区,分析了1983-2015年间沙地典型飞播样地群落演替特征及其对环境因子的响应,建立基于10个植物功能性状的毛乌素沙地潜在种库,进一步筛选飞播恢复下沙地不同演替阶段的适生植物。研究表明:(1)飞播恢复下的毛乌素沙地植物群落分为三个演替阶段:固沙先锋物种群落、沙生植物为主的杂类草群落、中生植物为主的杂类草群落。(2)土壤因子是群落演替的主要驱动力,其中土壤全氮、土壤总有机碳、土壤硝态氮是影响群落演替的关键因素。(3)基于功能性状筛选出29种适生物种用于植被恢复,演替第一阶段可用雾冰藜、猪毛菜等,演替第二阶段可用拂子茅、无芒隐子草等,演替第三阶段可用草地风毛菊、猪毛蒿等。通过物种功能性状特征可以快速选择适合沙地退化生态系统修复的候选物种,为植被恢复提供了一定的理论支持。     

Local variation in rodent communities of Sitka spruce plantations: the interplay of successional stage and site-specific habitat parameters

Habitat associations of wood mouse Apodemus svlvaticus, bank vole Clethrionomvs glareolus and field vole Microtus agrestis were analysed during a chronosequence study of succession in Sitka spruce Picea stichensis plantations in Hamsterley Forest, northeast England In mature plantations (ca 40 yr after planting), A svlvaticus and C glareolus were both abundant, in clear-felled areas the former was usually dominant, in young plantations (5-8 yr after planting) either of the three species was dominant at different sites Pooling all sites, in young plantations rodent communities were most diverse, because of an inter-site component (β-diversity), although within sites, young plantations and mature plantations had similar diversities Clear-felled areas showed least rodent diversity Detrended Correspondence Analysis was used to describe the taxonomic and structural changes in vegetation during succession Canonical Correspondence Analysis showed that in young plantations C glareolus was associated with dense ground cover, provided mostly by heather Microtus agrestis was most commonly associated with Deschampsia flexuosa, whereas A svlvaticus was not strongly associated with any plant species Spatial heterogeneity in soils explained much of the inter-site variation in vegetation winch in turn explained much of the β-diversity of rodent communities in young plantations     

Succession of bee communities on fallows

Wild bee communities were studied on one- to five-year-old set-aside fields with naturally developed vegetation (n = 20). and old orchard meadows (n = 4) to analyse effects of secondary succession on species diversity, resource use and associated life history traits. General theory predicts a steady increase of species richness with age of succession. In contrast, we found a first maximum in species richness of bees on two-year-old set-aside fields and a second on old meadows. Successional changes of bee communities were related to changes of vegetation. The transition from pioneer successional stages, dominated by annuals, to early successional stages, dominated by perennials, resulted in the highest species richness of flowering plants in the second year within the first five years of succession. Species richness of flowering plants was the best predictor variable for species richness of bees, whereas the cover of flowering plants correlated with the abundance of bees. Annual plants were visited more often and perennials less often than expected from their flower cover. Halictidae tended to prefer flowers of annuals, whereas Megachilidae. Apidae and Anthophoridae significantly preferred perennials. In departure from successional theory, body size, proportion of specialised bees and proportion of parasitic bees did not significantly increase with successional age, but number of generations and the proportion of soil-nesting bees decreased with successional age. Comparison of different management types showed that set-aside fields with naturally developed vegetation supported much more specialised and endangered bee species than set-aside fields sown with Phacelia tanacetifolia.     

Within‐stand spatial structure and relation of boreal canopy and understorey vegetation

Question: How do spatial patterns and associations of canopy and understorey vegetation vary with spatial scale along a gradient of canopy composition in boreal mixed‐wood forests, from younger Aspen stands dominated by Populus tremuloides and P. balsamifera to older Mixed and Conifer stands dominated by Picea glauca? Do canopy evergreen conifers and broad‐leaved deciduous trees differ in their spatial relationships with understorey vegetation? Location: EMEND experimental site, Alberta, Canada. Methods: Canopy and understorey vegetation were sampled in 28 transects of 100 contiguous 0.5 m × 0.5 m quadrats in three forest stand types. Vegetation spatial patterns and relationships were analysed using wavelets. Results: Boreal mixed‐wood canopy and understorey vegetation are patchily distributed at a range of small spatial scales. The scale of canopy and understorey spatial patterns generally increased with increasing conifer presence in the canopy. Associations between canopy and understorey were highly variable among stand types, transects and spatial scales. Understorey vascular plant cover was generally positively associated with canopy deciduous tree cover and negatively associated with canopy conifer tree cover at spatial scales from 5–15 m. Understorey non‐vascular plant cover and community composition were more variable in their relationships with canopy cover, showing both positive and negative associations at a range of spatial scales. Conclusions: The spatial structure and relation of boreal mixed‐wood canopy and understorey vegetation varied with spatial scale. Differences in understorey spatial structure among stand types were consistent with a nucleation model of patch dynamics during succession in boreal mixed‐wood forests.     

Species associations and nurse plant effects in patches of high-Andean vegetation

Abstract. In high-elevation communities of the southern Andes, plant cover is low due to severe environmental conditions and vegetation occurs mostly as isolated small (< 1 m²⁾ patches. Most patches are dominated by flat cushion plants. We evaluated patterns of plant species co-occurrence and species affinity for patches with and without cushion plants and different species richness. We mapped and recorded species composition of patches occurring within two 20 m × 20 m plots at the NE slope of Cerro Chall-Huaco, Nahuel Huapi National Park, Argentina. In these plots, we identified 32 and 24 plant species, and a maximum of 15 and 12 species per patch, respectively. The community was characterized by positive associations between species. Patches in which either of the common cushion plants Mulinum leptacanthum and Oreopolus glacialis occurred sustained richer communities than patches in which they were absent. Patches dominated by different cushion plants did not differ in species composition, but species differed in their affinities for patches with different numbers of species. Because richness increased with patch size and patch size with time, differential affinities of plant species suggest that successional changes take place in the patches. Some small herbaceous species appear to act as late colonizers, mostly restricted to species-rich patches. Flat cushion plants are considered ‘nurse plants’; they strongly modify micro-environmental conditions and allow establishment and survival of associated species.     

低覆盖度固沙林的乔木分布格局与防风效果

低覆盖度植被是我国干旱、半干旱区经过漫长的自然演替过程逐步发育形成且广泛分布的植被类型。前人研究认为,植被覆盖度达到40%为固定沙地,40%-20%为半固定-半流动沙地。但在实践观察中发现:在低密度(或覆盖度)时,灌丛的水平分布格局对固定流沙和阻止风沙流的作用差异显著。在干旱区、半干旱区,存在着大量天然的乔木疏林,其覆盖度均在低于40%,地表处于半流动状态,而配置成行带式后,即使覆盖度降低到20%时,地面也不会出现风蚀现象。因此,在内蒙古浑善达克沙地,针对覆盖度在20%左右的乔木疏林,同时测定了随机与行带式两种分布格局的防风阻沙效果。结果表明:(1)在不同的对照风速下,行带式配置的林内的相对风速均低于随机分布,其中在200 cm高度处行带式配置的平均相对风速比随机分布的低53.89%,在50 cm高度处低36.82%;(2)行带式林内的水平风速流场变化有一定规律,而随机分布林内风速流场变化主要受树冠在空间的分布影响,变化非常复杂;(3)随机分布的疏林内出现风速超过旷野对照的现象,在50 cm和200 cm的两个观测高度上分别有约27.45%和22.55%的风速测定值超过对照风速,说明出现明显的局部风速"抬升"现象,形成了强的涡流;(4)行带式配置林内的平均地表粗糙度达到1.01 cm,比随机分布的疏林内增大约5倍之多;(5)总体而论,行带式分布格局第1带降低风速的作用最显著,第2带及其以后各带间的风速均比第1带后的风速小,但逐带降低的叠加效益不明显;(6)由于乔木基本(枝下高)没有枝条对风的阻碍,乔木行带式固沙林在迎风面的第1林带的基部有一定的风力"抬升"作用,对林带基部地面产生较强的侵蚀作用,多数第1带树木的根系被侵蚀裸露,过境的风沙流只能在林带后树冠外侧堆积;(7)随机分布林内在许多位置出现了非常低的地表粗糙度,地表粗糙度低的位置基本与风速"抬升"区相吻合,这种"抬升"区形成的强的涡流是疏林内出现风蚀坑的重要因素,这也是浑善达克沙地出现榆树与风蚀坑相间分布的主要原因。     

An Analysis of Vegetation Restoration on Opencast Oil Shale Mines in Estonia

We compared four types of 30‐year‐old forest stands growing on spoil of opencast oil shale mines in Estonia. The stand types were: (1) natural stands formed by spontaneous succession, and plantations of (2) Pinus sylvestris (Scots pine), (3) Betula pendula (silver birch), and (4) Alnus glutinosa (European black alder). In all stands we measured properties of the tree layer (species richness, stand density, and volume of growing stock), understory (density and species richness of shrubs and tree saplings), and ground vegetation (aboveground biomass, species richness, and species diversity). The tree layer was most diverse though sparse in the natural stands. Understory species richness per 100‐m² plot was highest in the natural stand, but total stand richness was equal in the natural and alder stands, which were higher than the birch and pine stands. The understory sapling density was lower than 50 saplings/100 m² in the plantations, while it varied between 50 and 180 saplings/100 m² in the natural stands. Growing stock volume was the least in natural stands and greatest in birch stands. The aboveground biomass of ground vegetation was highest in alder stands and lowest in the pine stands. We can conclude that spontaneous succession promotes establishment of diverse vegetation. In plantations the establishment of diverse ground vegetation depends on planted tree species.     

Past and present vegetation ecology of Laetoli, Tanzania

We are attempting to set up a new protocol for palaeoecological reconstruction in relation to the fossil hominin site Laetoli, Tanzania. This is based on the premise that habitat variability in the past was at least as great as at present; that this variability at the landscape level is a function of variations in geology, soils, and topography rather than climate; and that vegetation type at the landscape level can be reconstructed from these environmental variables. Measurable variation in climate in tropical Africa today occurs over distances of at least 100 km, so that ranges of habitat variation within the limited area of Laetoli today can be reconstructed in relation to soils and topography, and the effects of climate changes are then estimated in relation to these other factors. In order to document the modern vegetation, we have made voucher collections of plants in the Laetoli region, recorded distributions of plants by habitat, climate, soil, and topography, and mapped the vegetation distributions. Results show that areas of low relief have soils with impeded drainage and dense Acacia drepanolobium woodland, having low canopies when disturbed by human action, higher when not; shallow brown soils on volcanic lavas have four woodland associations, two dominated by Acacia species, two by Combretum-Albizia species; shallow volcanic soils to the east have a woodland association with Croton-Dombeya-Albizia species; elevated land to the east on volcanic soils has two associations of montane-edge species, one with Croton-Celtis-Lepidotrichilia, and the other with Acacia lahai; the eastern highlands above 2,750 m have montane forest; seasonal water channels flowing from east to west have three Acacia riverine woodland associations; three deep valleys to the north of the area have dense riverine woodland with Celtis, Albizia, Euclea, Combretum, Acacia spp.; emergence of springs at Endulen feed a perennial stream with closed gallery forest with Ficus-Croton-Lepidotrichilia; and, finally, recent ash falls have produced immature alkaline soils with calcrete formation and short grass vegetation. All of these vegetation associations have been modified by human disturbance to greater or lesser degrees, and we have attempted to allow for this both by basing the associations on the least modified areas and by predicting how the associations, or parts of associations, have been altered by human action. Past land forms at Laetoli have been based on the geology and geomorphology of the area. Past vegetation patterns were estimated by superimposing present distributions of plant associations on equivalent landforms in the past, assuming similar climate to the present. This indicates the overall pattern of vegetation at Laetoli to have been a mosaic of low and tall deciduous woodlands and with riverine woodland and forest associations along water courses. Low woodlands would have been dominated by Acacia species, and tall woodlands by Combretum-Albizia species, with increasing increments of montane species, such as Croton species, to the east of the area. Riverine woodlands would have been dominated by Acacia-Euclea species, with wetter associations (downriver or linked with spring activity) supporting gallery forest with Ficus, Celtis, and Croton species. These are all species associations common in the area today, and with landforms little changed in the past, and assuming similar climate, there is every reason to predict that they would have been present in the past. Moreover, Pliocene environments lack the human disturbance that has destroyed much of the present day vegetation. Presence of woodlands is supported by fossil wood attributed to several of the tree species present in the area today and by similarities in the mammalian community structure between past and present. Having established the pattern for Pliocene vegetation based on climatic variables existing today, we then predict the effects of past variations in climate.     

Poplar plantations along regulated rivers may resemble riparian forests after abandonment: a comparison of passive restoration approaches

Abandoning hybrid poplar plantations may be an alternative strategy for enlarging natural riparian corridors along regulated rivers where forest regeneration no longer takes place. Despite the generally high local diversity of plants in poplar plantations, their capacity to converge towards riparian forests following abandonment remains largely untested and uncertain, because maintenance‐related disturbance of plantations favors ruderal, not strictly riparian specialists. We assessed the spontaneous recolonization of vegetation in abandoned hybrid poplar plantations following two management strategies: harvesting or simple abandonment of standing trees. The floristic composition in four chronosequences of 10 active (1–15 years), 17 harvested (1–15 years), and 10 abandoned (8–20 years) hybrid poplar plantations, as well as 10 riparian sites established at gravel bars that appeared following the cessation of in‐channel gravel mining (8–25 years) along the highly regulated Garonne River (SW France) was assessed in the framework of ecological disturbance theory. Both harvested and abandoned sites still resembled active plantations more than riparian forests. When poplar resprouting was low after harvesting, sites were dominated by light‐demanding, nitrophilous herbs, sub‐shrubs, and vines showing both competitive and ruderal traits, and vegetation composition remained stable over time. Abandoned and harvested sites with high poplar resprouting developed forest communities in which competitive species that tolerate and generate shade dominated, and tree species recruitment was higher. Riparian sites hosted the highest number of indicator species, mainly wetland and exotic. Simple passive restoration strategies like abandonment of plantations can help create valuable ecosystems, although ones that diverge from riparian forests colonizing new fluvial landforms.