鄂西南五种野生荚蒾属植物种群结构与动态特征研究

Population structure and dynamic characteristics of five wild Viburnum plants in Southwest Hubei,China

为探明鄂西南地区野生荚蒾属(Viburnum)植物的种群数量特征及区域分布状况,并揭示宜昌荚蒾(V.erosum)、桦叶荚蒾(V.betulifolium)、合轴荚蒾(V.sympodiale)、茶荚蒾(V.setigerum)、荚蒾(V.dilatatum)5种荚蒾属植物种群的生存现状及发展趋势,在鄂西南金子山国有林场、木林子国家级自然保护区及七姊妹山国家级自然保护区,共布设27 hm~2固定动态监测样地对荚蒾属植物进行调查,通过对5种荚蒾属植物种群进行年龄结构、动态量化分析和静态生命表以及相关曲线等研究,探讨荚蒾属植物种群结构与动态特征及未来发展潜力。结果表明:(1)鄂西南荚蒾属植物在分布区域及种群数量大小上均存在明显差异。(2)种群结构与动态分析显示,5种荚蒾属植物种群年龄结构呈现为金字塔型,幼龄阶段种群个体数量较多,具有较强的增长潜力,但对外界干扰均具有较强的敏感性。(3)静态生命表显示,5种荚蒾属植物存活量均随着龄级的增加而单调递减;消失率与死亡率曲线变化趋势相似,但不同植物消失率与死亡率曲线波动具有差异性;种群存活曲线均趋近于Deevey-Ⅱ型。(4)4个生存函数曲线表明,5种荚蒾属植物种群均表现出前期大量减少、中期趋于稳定、后期衰退的特点。综上认为,鄂西南荚蒾属植物资源丰富,对其属植物的合理开发具有一定的科学性和可行性,幼龄阶段时可适当进行人工疏伐,提高保存率;中龄稳定阶段时可筛选观赏性状优势种进行适当开发利用;部分物种则需要加强保护,以维持该地区生物多样性。

To explore the population quantitative characteristics and regional distribution of wild Viburnum plants in Southwest Hubei,and reveal the survival status and development trend of the following five Viburnum species:V.erosum,V.betulifolium,V.sympodiale,V.setigerum and V.dilatatum.A total of 27 hm 2 dynamic monitoring stands were set up in Jinzi Mountains National Forest Farm,Mulinzi National Nature Reserve and Qizimei Mountains National Nature Reserve in Southwest Hubei.The age structure,dynamic quantitative analysis and static life table of five Viburnum species were used to explore the population structure,dynamic characteristics and future development potential of Viburnum plants.The results were as follows:(1)The distribution area and population size of Viburnum plants in Southwest Hubei were significantly different.(2)The age structure of the five Viburnum species displayed as the pyramidal type summarized from population structure and dynamic analysis.The number of individuals of each population was large at the young stage(89.48%of V.erosum in Jinzi Mountains,76.38%of V.betulifolium,67.24%of V.erosum in Mulinzi,62.11%of V.dilatatum,56.53%of V.sympodiale,58.44%of V.setigerum),and only a small proportion of individuals(0.18%of V.erosum in Jinzi Mountains,0.85%of V.betulifolium,3.29%of V.erosum in Mulinzi,3.97%of V.dilatatum,8.37%of V.sympodiale,2.79%of V.setigerum)at the old stage.The young stage plants of five Viburnum species all had strong growth potentials but were sensitive to external disturbances.(3)The survival quantity of the five Viburnum species was decreasing monotonically with increasing age class presented by static life tables.Except for V.setigerum,the life expectancy reached peak at the young age,all the other Viburnum species populations reached the peak at the middle age.The change trend of mortality rate and vanish rate were similar,but the fluctuation of vanish rate and mortality rate curves were different among different species.The survival curves were tended to be Deevey-Ⅱtype.(4)The four survival function curves showed that all five Viburnum species populations exhibited a substantial decrease at the early stage,stabilization at the middle stage,and decline at the late stage.To sum up,plant resources of Viburnum species are abundant in Southwest Hubei.Therefore,it is scientific and feasible to exploit Viburnum plants rationally.At the young stage,artificial thinning can be carried out appropriately to improve the preserving rate.During the stable middle stage,the dominant species which have good ornamental characters can be selected for appropriate development and utilization.However,some species need to be protected to maintain biodiversity in this area.