野生大熊猫与放牧家畜采食对冷箭竹无性系种群特征的影响

Effects of Herbivory by Ailuropoda melanoleuca and Grazing Livestock on Population Characteristics of Bashania faberi Clones

种群特征是植物最为直观、可测度的生物学指标,是植物适应外部干扰和环境波动的功能性反应,通过分析冷箭竹(Bashania faberi)无性系种群在野生大熊猫(Ailuropoda melanoleuca)和放牧家畜采食后的种群特征,以便了解大熊猫与放牧家畜对冷箭竹无性系种群变化的影响强度,以及冷箭竹无性系种群对不同动物采食的响应策略。为此,采用样方法测定了大熊猫国家公园卧龙片区内大熊猫与放牧家畜利用后的冷箭竹无性系种群特征,并与对照样地进行了比较。结果表明,野生大熊猫和放牧家畜都降低了冷箭竹层片的覆盖度,分别为对照的87.85%和52.95%,放牧家畜的影响强度是野生大熊猫的1.66倍。放牧家畜的采食阻碍了1年生竹的萌发更新和生长发育,与对照相比,1年生竹密度减少了97.07%、基径小了27.78%、株高低了87.93%,对其余年龄和种群的基径生长没有显著影响(P>0.05),但显著降低了植株的高度生长(P<0.05)。野生大熊猫的利用主要影响1年生竹的数量增长,密度降低了28.13%,且有利于2年生竹、多年生竹和种群的数量维持,以及各年龄分株的基径与株高生长。因此家畜放牧样地的种群结构中径级分布与对照相似,呈正态分布模式,峰值处于3.1~6.0 mm,数量占比为82.21%;而其高度级的分布截然不同,峰值偏向于低阶植株,株高60 cm以下植株的数量占比达到41.21%。野生大熊猫利用样地的种群结构(径级和高度级)与对照样地具有相似的正态分布格局,基径2.1~6.0 mm和株高61~140 cm的数量占比最大,径级为79.44%、高度级为70.01%。可见放牧家畜对冷箭竹无性系种群的影响远大于野生大熊猫采食,过渡利用将造成冷箭竹资源的衰退,因此加强家畜放牧数量和放养区域的管控是保护野生大熊猫及其栖息地的有效措施。

Population characteristics are the most intuitive and measurable biological indicators of plants and the functional responses of plants to external interferences and environmental fluctuations.By analyzing the population characteristics of Bashania faberi clones after feeding by the wild giant pandas(Ailuropoda melanoleuca)and grazing livestock,we can understand the impact intensity of the giant pandas and grazing livestock on the clonal population dynamics of Bashania faberi,and the response strategy of clonal populations of Bashania faberi to herbivory of different animals.Therefore,the clonal population characteristics of Bashania faberi in Wolong Area of the Giant Panda National Park after feeding by giant pandas and grazing livestock were determined by quadrat method,and compared with those in the control plots.The results showed that wild giant pandas and grazing livestock reduced the coverage of bamboo forest to 87.85%and 52.95%of the control,respectively.The impact intensity of grazing livestock was 1.66 times that of wild giant pandas.Feeding by grazing livestock hindered the germination,regeneration,growth and development of one-year-old bamboo.Compared with the control,the density of one-year-old bamboo decreased by 97.07%,the basal diameter decreased by 27.78%,and the plant height decreased by 87.93%.Grazing livestock had no significant impact on the basal diameters of bamboo culms of other ages or populations(P>0.05),but significantly reduced the heights of other bamboo culms(P<0.05).Feeding by wild giant pandas mainly affected the number of one-year-old bamboo,causing a decrease of density by 28.13%,and was conducive to maintaining the numbers of two-year-old and even older bamboo and the populations,as well as the basal diameters and the plant heights of bamboo ramets of all ages.Therefore,the diameter distribution of the bamboo populations in the plots for livestock grazing was similar to that in the control plots,which followed a normal distribution pattern with the majority being 3.1~6.0 mm and accounting for 82.21%of the total number.However,the height distribution was quite different,and the peak shifted to the lower end.The number of bamboo culms less than 60 cm in height accounted for 41.21%.The population structure(basal diameter and plant height)of bamboo in the plots for wild giant panda herbivory had a similar normal distribution like that in control plots.Most bamboo culms were 2.1~6.0 mm in basal diameter,accounting for 79.44%of the total number,and were 61~140 cm in plant height,accounting for 70.01%.Thus,livestock grazing has a much greater impact on the clonal populations of Bashania faberi than wild giant panda herbivory,and excessive feeding will lead to the degradation of Bashania faberi resource.Therefore,restricting the quantity of grazing livestock and their grazing area is an effective measure to protect the wild giant pandas and their habitats.