Gap dynamics of natural Populus euphratica floodplain forests affected by hydrological alteration along the Tarim River: Implications for restoration of the riparian forests
Gap dynamics of natural Populus euphratica floodplain forests affected by hydrological alteration along the Tarim River: Implications for restoration of the riparian forests
复制标题
塔里木河沿岸水文变化影响的天然胡杨漫滩森林林隙动态：对河岸森林恢复的启示
DOI：
10.1016/j.foreco.2019.02.009
复制
发表时间：
2019-04-15
影响因子：
3.7
通讯作者：
Rouzi, Aihemaitijiang
中科院分区：
文献类型：
--
作者：
Keram, Ayjamal;Halik, Umut;Rouzi, Aihemaitijiang
由于气候变化和人类过度活动，西北地区塔里木河径流动态变得更加明显。了解水文变化对胡杨河岸森林的生命策略和动态的影响变得越来越重要。这种干扰导致的林隙改变了沙漠河岸森林生态系统的结构和功能。然而，对于这种特殊林型的林隙形成及其动态的研究却十分缺乏，林隙扰动的主要驱动力一直未知。在本研究中，我们调查了胡杨林间隙的几个参数，如间隙大小、间隙年龄、间隙分数和间隙制造者，以量化中国西北干旱塔里木河沿岸天然洪泛区森林的间隙干扰状况。在塔里木河中游地区，共调查了6个50 m×50 m样地，总面积1.5 hm(2)，共263个开缝者和60个空窗。结果显示，间隙比例< 5%，约28.5%的扩大间隙尺寸为1.0至1.2（间隙直径与树高之比），特别是在1997-2006年左右形成时。沙漠河岸森林扩大林隙的中值尺寸（140.57 m(2)）小于热带森林。胡杨是最丰富的间隙制造者，其在间隙制造者中所占的比例是其他物种的 12-14 倍。此外，间隙制造者对森林间隙的大小也有贡献，间隙制造者的数量与扩大的间隙大小之间存在显着相关性，特别是那些 50-60 年前形成的间隙（R-2 = 0.455，P < 0.01）。活树与死树的胸径分布表明，大多数胡杨死亡发生在小尺寸类别中。然而，在大类中，活着的树木同样常见，这表明在这些受到缺水等不良生境影响的胡杨林中，大树不仅受到伤害或死亡。我们得出的结论是，自20世纪70年代以来，气候变化和人类活动（灌溉用水增加）导致区域范围内水资源逐渐减少，并导致塔里木河沿岸森林的林隙频率增加。本研究结果为胡杨生态恢复、改善荒漠河岸森林的可持续管理提供了有益的启示。
Due to climate change and excessive human activities, runoff dynamics of the Tarim River in northwest China become more pronounced. Understanding the effects of hydrological alteration on the life strategy and dynamics of the Populus euphratica riparian forests is becoming increasingly important. Forest gaps led by such disturbances change the structure and function of the desert riparian forest ecosystems. However, there is a lack of research on the gap formation and dynamics of this special forest type, for which the main driving force of the gap disturbance has always been unknown. In this study, we investigated several parameters of P. euphratica forest gap, such as gap size, gap age, gap fraction, and gap makers to quantify the gap disturbance regimes in the natural floodplain forests along the Tarim River in arid northwest China. In the middle reaches of the Tarim River, a total number of 263 gap makers and 60 gaps in six 50 m x 50 m plots with a total area of 1.5 hm(2) were investigated. The result showed that gap fraction was < 5%, and approximately 28.5% of the expanded gaps were from 1.0 to 1.2 in size (ratio of gap diameter to tree height), especially when formed around 1997-2006. The median size of the expanded gap (140.57 m(2)) in the desert riparian forests was smaller than in tropical forests. P. euphratica was the most abundant gap maker, and its share among gap makers was 12-14 times larger than another species. Furthermore, gap makers contributed to the forest gap size, as shown by a significant correlation between the number of gap makers and the size of expanded gaps, especially those that had been created 50-60 years ago (R-2 = 0.455, P < 0.01). The DBH distribution of living trees versus dead trees showed that most P. euphratica mortality occurred in small size classes. However, living trees were equally frequent in large classes, which suggested that large trees were not exclusively injured or died in these P. euphratica stands that were affected by poor habitats, such as water scarcity. We concluded that climate change and anthropogenic activities (increasing water use for irrigation) since the 1970s led to the progressive decrease in water resources at the regional scale and resulted in a higher frequency of forest gaps in the riparian forests along the Tarim River. The results of this study provide useful implications for ecological restoration of P. euphratica to improve sustainable management of desert riparian forests.