植被、海拔、人为干扰对大中型野生动物分布的影响——以九寨沟自然保护区为例

利用九寨沟自然保护区内8条动物监测样线在2003—2010年的生态监测数据,分析了植被、海拔、人为干扰对大中型野生动物分布的影响,结果显示:1)本监测共记录到保护区内大中型野生动物26种,其中兽类18种,鸟类8种,属于我国Ⅰ级、Ⅱ级保护动物的分别有5种和11种。2)针阔混交林和针叶林是大中型野生动物种类最丰富的两种植被类型(分别有26种和17种),阔叶林和灌丛次之(分别为10种和12种),草地最少(2种)。3)海拔2400 m以下的地方,大中型野生动物种类稀少,为10种,2400—2599 m海拔段物种数增加至20种,之后随海拔上升物种丰富度下降。4)人为干扰显著影响大中型野生动物的空间分布:历史上的人类活动将原生森林植被转化为次生的落叶阔叶林、灌丛和草地,使树正、亚纳和尖盘等地下坡位(相对海拔0—199 m)的大中型野生动物的物种丰富度降低(分别为4、2、2种)。包括旅游活动和交通在内的人为干扰,可能导致附近50m海拔范围内保护动物的缺失,并使下坡位的某些物种向高海拔处移动。生境破碎化则使野生动物的种类组成发生改变,使原有森林内部优势种,如羚牛(Budorcas taxicolor),逐渐被适应能力强的物种,如豹猫(Prionailurus bengalensis)、雉鸡(Phasianuscolchicus)和野猪(Sus scrofa)等所取代,并将长期影响野生动物种群的存活。当前九寨沟自然保护区大中型野生动物的分布是植被、海拔与人为干扰综合作用的结果。

Effects of vegetation, elevation and human disturbance on the distribution of large- and medium-sized wildlife: a case study in Jiuzhaigou Nature Reserve

Animals are integral components of ecosystems,and play important roles in maintaining their function.However,animals are affected by various factors in their habitats.For example,vegetation is an important component of habitat,providing refuge and food.A single mountain may provide a series of climatically different ecological zones over a short elevation change and thus provide diverse habitats for wildlife.Both vegetation and elevation affect wildlife distribution.Protected areas are attracting an increasing number of people and are vulnerable to urban development,which inevitably influences the activity and survival of wildlife.Jiuzhaigou National Nature reserve,which is located in the north of Sichuan Province,in southwest China,has a population of more than 1000 indigenous people,along with a high diversity of wildlife,and in recent years has received nearly 2 million visitors each year.To identify the effects of the environment and human activities on wildlife,and to develop biodiversity protection measures,long-term population monitoring is necessary.Data were analyzed from 8 wildlife monitoring transects in Jiuzhaigou Nature Reserve from 2003 to 2010 to investigate the effects of vegetation,elevation and human disturbance on the distribution of large-and medium-sized wildlife.Twenty-six species of large-and medium-sized wildlife were observed,consisting of 18 species of animals and 8 species of birds,5 and 11 species of which belonged to the first and second class of protected animals in China.Large-and medium-sized wildlife were most abundant in mixed and coniferous forest(26 and 17 species);less in deciduous broadleaved forest and shrub(10 and 12 species);and least in grassland(2 species).Only 10 species were found below 2400 m;the number increased to 20 between 2400 and 2599 m;after which the number declined with increasing elevation.Human disturbance has had significant effects on large-and medium-sized wildlife distribution.Because of human activities,the original primary forests changed into secondary deciduous broadleaved forest,shrub and grassland,which led to a lower abundance of large-and medium-sized wildlife on the lower slopes(elevation of 0–199 m relative to the starting point of the monitoring transect) in Shuzheng,Yanan and Jianpan(4,2 and 2 species respectively).Human disturbances,including tourism and traffic,probably led to loss of protected animals in the adjacent 50 m elevation range by causing some species to move from the lower slopes to higher elevations.Habitat fragmentation has changed wildlife species community composition,and led to the original forest-interior dominant species(such as Budorcas taxicolor) being gradually replaced by species with strong adaptability(such as Prionailurus bengalensis,Phasianus colchicus and Sus scrofa),and is likely to continue to affect population survival over the long term.In summary,vegetation was the primary factor affecting large-and medium-sized wildlife distributions;vegetation distribution determined wildlife distribution in this reserve.Human disturbance directly and indirectly decreased species richness at lower elevations by leading to disturbance avoidance and vegetation change,respectively.Elevation had an indirect effect on wildlife distribution by creating a gradient in the natural environment and affecting the extent of human activities.Currently,the distribution of large-and medium-sized wildlife in Jiuzhaigou nature reserve is jointly affected by vegetation,elevation and human disturbances.