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湖北南河国家级自然保护区及周边七子花群落特征与种群结构

Community Characteristics and Population Structure of Heptacodium miconioides within and around the Nanhe National Nature Reserve,Hubei

  • 摘要: 七子花(Heptacodium miconioides Rehder)为我国特有的落叶灌木或小乔木,被列入国家重点保护野生植物名录和世界自然保护联盟(IUCN)受威胁植物名录。2022年8月,被认为在湖北消失115年的七子花,在谷城南河国家级自然保护区及其周边被重新发现。本研究以新发现的3个七子花种群(傅家寨、玉皇阁和李庙镇)为研究对象,分析研究其生境特征、伴生群落物种组成、种群结构和受威胁因素。分布区的植被为典型的落叶阔叶林,以小叶鹅耳枥(Carpinus stipulata H. J. P. Winkl.)、化香树(Platycarya strobilacea Siebold & Zucc.)、七子花和栓皮栎(Quercus variabilis Blume)为优势种。新发现种群共记录到151株七子花,基本都分布于海拔1000-1300米的山脊或崖壁上。七子花的大小级结构图呈纺锤型,表明新发现种群为衰退型,实生苗更新不足。新发现的151株个体中有137株(91%)产生萌蘖,共产生936个萌蘖,平均每株6.83个。大量的萌蘖在很大程度上弥补了幼苗的不足,使该物种能够占领其生态位,利于种群的维持。新发现种群位于偏远山区的山脊和崖壁上,人为干扰较小,因此可以推测内因是其种群衰退的主要驱动力。建议对周边区域开展更大规模的调查,同时采用包括就地保护、人工扩繁、迁地保护和野外回归在内的整合保护计划加强对七子花的保护和可持续利用。

     

    Abstract: Heptacodium miconioides Rehder (Seven-son flower) is a vulnerable plant species on the IUCN Red List of Threatened Species and is also on the List of National Key Protected Wild Plants in China. This shrub or small tree species was first recorded in 1907 by Ernest Wilson in western Hubei, central China, and later found in Zhejiang and Anhui. However, after the first record, it was not found in the next 115 years and was presumed extinct in Hubei. Then, in August 2022, it was rediscovered in the Hubei Nanhe National Nature Reserve, which is ca. 100 km away from its type locality. The vegetation type is typical deciduous broad-leaved forest and dominated by Carpinus stipulata H. J. P. Winkl., Platycarya strobilacea Siebold & Zucc., H. miconioides, and Quercus variabilis Blume. Our surveys located 151 individuals at three localities with elevations of 1, 000-1, 300 m. The size class structure (main stem) of the rediscovered populations is spindle-shaped, indicating that populations are declining due to insufficient seedlings. The 151 individuals produced 936 sprouts, 91% of the individuals produced sprouts, and the number of sprouts per sprouting individual was 6.83. The abundant sprouting can compensate for the scarcity of seedlings, maintain populations, and enable the species to persist in the niche. Because the populations are at remote mountain ridges and cliffs with few human disturbances, the population decline may be mainly caused by internal factors. We recommend additional field surveys for other undiscovered populations and an integrated conservation plan, including in situ conservation, artificial cultivation of seedlings, ex situ conservation, and reintroduction.

     

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