Riparian vegetation survival and establishment in gravel‐bed rivers depends on the balance between vegetation growth and flood disturbance. We present four examples of vegetation and landform development in gaps (linear open spaces) between established islands and/or floodplain within a reach of the middle Tagliamento River, Italy. Gaps offer shelter to vegetation, supporting higher colonization success and different vegetation‐landform evolution pathways. Time sequences of aerial images track vegetation development over 30 years in the four gaps. In combination with the flood disturbance time series, we interpret vegetation dynamics and identify the fate of sexual and asexual reproduction strategies by observing vegetation expansion from lines of young plants and shrubs and from uprooted deposited trees and pioneer islands, respectively. Analysis of image sequences reveals common features across the four gaps that are generalized to extend a conceptual model of island development. Growing conditions, disturbance energy and time (window of opportunity) between major floods are the main controls on vegetation colonization. These vary among rivers, among reaches along the same river and locally, as in the investigated gaps, allowing different tree species with different life history traits (e.g., Populus nigra, Alnus incana) to engineer local river landforms in different and complementary ways. Although the conceptual model is inspired by observations on the Tagliamento River, consideration of species life history traits and the joint influences of growing conditions, disturbance energy and windows of opportunity provide a framework that may be applied to other temperate rivers where trees drive landform development.

中文翻译：

---

扩展河流岛屿开发的概念模型，以纳入不同的树种和环境条件

河床植被在砾石河中的生存和建立取决于植被生长和洪水扰动之间的平衡。我们以意大利塔利亚门托河中游范围内已建立的岛屿和/或漫滩之间的缝隙（线性开放空间）中的植被和地形发育为例，给出四个例子。缺口为植被提供了庇护所，支持更高的定殖成功率和不同的植被地貌演化途径。航空影像的时间序列在四个间隔内跟踪了30年以上的植被发育。结合洪水干扰时间序列，我们分别通过观察年轻植物和灌木的生长以及连根拔起的树木和先锋岛的植被生长来解释植被动态并确定有性和无性繁殖策略的命运。图像序列分析揭示了跨越四个空白的共同特征，这些共同特征被普遍化以扩展岛屿发展的概念模型。大洪水之间的生长条件，干扰能和时间（机会之窗）是植被定殖的主要控制因素。这些差异在河流之间，沿同一河流的河段以及当地，如所调查的差距一样，允许具有不同生活史特征的不同树种（例如，杨（Populus nigra，Alnus incana）以不同的方式和互补的方式设计当地河流的地貌。尽管概念模型的灵感来自塔利亚曼多河的观测，但考虑到物种生活史特征以及生长条件，干扰能量和机会窗口的共同影响，这些框架可以应用于其他温带河流，在这些温带河流中树木驱动地貌发展。