新疆伊犁与哈萨克斯坦新疆野苹果〔Malus sieversii (Ledeb.) Roem.〕种群年龄结构

Age Structure of Malus sieversii Population in Ili of Xinjiang and Kazakhstan

人类活动和自然环境的胁迫加速了中亚地区新疆野苹果〔Malus sieversii (Ledeb.) Roem.〕种群栖息环境的丧失,新疆野苹果种群面积和生存力趋于下降。本文以第三纪孑遗植物新疆野苹果为研究对象,野外系统调查新疆野苹果种群的生存现状,比较新疆伊犁和哈萨克斯坦分布的新疆野苹果种群年龄结构及果实产量,对两地当前新疆野苹果种群变化进行了分析。研究结果显示:当前伊犁地区和20世纪70年代哈萨克斯坦新疆野苹果种群的龄级结构主要以中龄(1550 cm)树为主,而幼龄(015 cm)与老龄(5075 cm)树较少。1969年和1970年哈萨克斯坦的新疆野苹果种群生存力最弱,种群为衰退型(Deevey-Ⅲ),但其产量较高;2016年和2017年伊犁的新疆野苹果种群生存力相对较弱,种群趋于衰退(Deevey-Ⅲ),产量较低;2013年哈萨克斯坦新疆野苹果种群生存力相对最强,种群最稳定(Deevey-Ⅱ);幼龄个体的缺乏是新疆野苹果种群趋于衰退的关键因子。目前,在哈萨克斯坦新疆野苹果保护区内需进行适当放牧干扰,以扩大种子的传播,提高种子的萌发;新疆地区以建立保护区为主,杜绝新疆野苹果的采收和降低野果林内的割草强度,以保护幼苗的生存数量,提高新疆野苹果的种子库,加快新疆野苹果种群更新。

Environmental and human stress accelerate the loss of wild apple habitats in Central Asia,causing the decline of population and viability of wild apples. In this paper,the population of a tertiary relict plant Malus sieversii (Ledeb.) Roem. was studied. The status of wild apple population was systematically surveyed,and the age structure,fruit yield and population dynamic change of wild apple in Xinjiang (Ili River Valley) of China and Kazakhstan were compared. The results showed that the population age structure was currently and even in the 1970 s dominated by the middle-aged (15-50 cm) trees,and the proportion of young (0-15 cm) and old (50-75 cm)trees was low in the Ili River Valley of Xinjiang and Kazakhstan. Compared with the population in Xinjiang,the life vitality of wild apple population was weaker while the fruit yield was relatively high,and the population was in a severe decline (Deevey-Ⅲ) in Kazakhstan from 1969 to 1970. In 2013,the population of wild apple trees in Kazakhstan showed a strong life vitality and stable population structure (Deevey-Ⅱ). The key factor that resulted in the decline of wild apple population was the lack of young individual trees. Detailed advices were proposed to the conservation and regeneration of wild apple forest in Xinjiang and Kazakhstan. For Kazakhstan,an appropriate level of grazing was suggested to enhance the seed spreading and germinating. For Ili of Xinjiang,the conservation areas should be established,while the wild apple fruit collection and mowing in wild apple forest should be prohibited or under well control so as to protect the seedlings as well as the natural seed bank.