Alharthi Abdullah S, Abd-ElGawad Ahmed M, Assaeed Abdulaziz M
Plant Production Department, College of Food & Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia.
Department of Botany, Faculty of Science, Mansoura University, Mansoura 35516, Egypt.
Saudi J Biol Sci. 2021 Jan;28(1):360-370. doi: 10.1016/j.sjbs.2020.10.014. Epub 2020 Oct 15.
Invasive species have been considered as one of the most serious threats to the biodiversity of various ecosystems, particularly in arid regions. The present study aimed to assess the influence of the invasive shrub on the biodiversity of different habitats in Taif region, Saudi Arabia as well as to determine the highest habitat with seed bank of Soil samples were collected from three locations (Alwaht, Ash-shafa, and Ar Ruddaf), invaded with , and analyzed for the soil seed bank. A soil seed experiment was designed in a greenhouse, whereby emerged plant seedlings were left to grow for three months and identified as well as the species density and biodiversity were assessed under and outside the canopy of . Also, the floristic composition, life forms, and chorotype spectra of the plant species of the seed bank were analyzed. A total of 42 species, belonging to 23 families, were recorded in the soil seed bank. Asteraceae, Poaceae, and Cyperaceae were the major families (42.9%). The life form spectra of the recorded species were dominated by Therophytes (59.5%). Chorotype spectra analysis revealed that Mediterranean, Saharo-Arabian, and Irano-Turanian were the most represented elements. The species richness and evenness were higher outside the canopy, which indicates a negative effect of the invasive shrub on the plant biodiversity in the study area, particularly in Ar Ruddaf location. This could be attributed to the competition or allelopathic effect of . In contrast, the density of seeds was higher under the canopy compared to outside. The soil nutrients and moisture under the canopy were higher than outside canopy. The present study provides a deeper understanding of the most susceptible habitats or communities to the invasion by and thereby open the challenge toward control of this noxious plant and vegetation restoration.
入侵物种被认为是对各种生态系统生物多样性最严重的威胁之一，尤其是在干旱地区。本研究旨在评估入侵灌木对沙特阿拉伯塔伊夫地区不同栖息地生物多样性的影响，并确定种子库最高的栖息地。从三个被入侵的地点（阿尔瓦赫特、阿什沙法和鲁达夫）采集土壤样本，分析土壤种子库。在温室中设计了一个土壤种子实验，让长出的植物幼苗生长三个月，进行识别，并评估树冠下和树冠外的物种密度和生物多样性。此外，还分析了种子库中植物物种的植物区系组成、生活型和分布型谱。在土壤种子库中总共记录了42种植物，分属23个科。菊科、禾本科和莎草科是主要科（占42.9%）。记录物种的生活型谱以一年生植物为主（占59.5%）。分布型谱分析表明，地中海、撒哈拉 - 阿拉伯和伊朗 - 图兰是最具代表性的成分。树冠外的物种丰富度和均匀度较高，这表明入侵灌木对研究区域的植物生物多样性有负面影响，尤其是在鲁达夫地点。这可能归因于该灌木的竞争或化感作用。相比之下，树冠下该灌木种子的密度高于树冠外。树冠下的土壤养分和湿度高于树冠外。本研究更深入地了解了最易受该灌木入侵的栖息地或群落，从而开启了控制这种有害植物和植被恢复的挑战。
