黑龙江省东完达山地区东北虎猎物种群现状及动态趋势

猎物种群丰度是限制虎分布和数量的关键因子,因此猎物种群密度监测和估算是虎保护的重要内容之一。应用采用大样方法,地理信息系统技术和多元统计分析,研究了黑龙江东完达山东部地区东北虎猎物种群(马鹿、狍子和野猪)现状及动态变化趋势。结果表明:研究地区马鹿的种群平均密度为(0.2010±0.0270)只/km²、狍子的平均种群密度为(0.4980±0.0436)只/km²、野猪的平均种群密度为(0.3423±0.0275)只/km²。单因素方差分析表明,在相同生境下,3种有蹄类密度在在阔叶混交林中和杂木林中差异极为显著;不同的生境,3种猎物的猎物的密度也存在着显著差异。相关分析表明马鹿密度和野猪密度程正相关,而马鹿密度和狍子密度、狍子密度和野猪密度则不相关。 同1989年该地区东北虎猎物种群相比:1989-2002年的13 a时间内马鹿的年平均递减率为13.48%、狍子的年平均递减率为12.69%、野猪的年平均递减率为1.89%。

Population status and dynamic trends of Amur tiger's prey in Eastern Wandashan Mountain, Heilongjiang Province

Ungulate depletion is a major factor driving the current decline of wild Amur tiger Panthera tigris altaica. To conserve this globally threatened species, we should monitor their prey densities timely. It is often desirable to estimate absolute densities of prey population across large areas for effective tiger conservation and management. However, determining absolute density is complex and often controversial. Ungulate are notoriously hard to completely or partially survey using direct counts in Northeast China for rare sightings, poor visibility in dense forests, manpower and budget limit and surveyor must rely on indirect snow signs. For this reason, the line transect methods often are used to census ungulate density in winter. Several indirect sampling methods of them have been proved to be cost-effective, repeatable and objective, but other indirect counting methods are frequently unreliable and usually require independent calibration or confirmation. On the basis of the stratification sampling principle, from January, 2002 to March,2004, the population density status and dynamic trends of three main Amur tiger's prey species (i.e., wild boar (Sus scrofa), red deer(Cervus elaphus)and roe deer (Capreolus pygargus)) were investigated as a prey baseline data for tiger conservation in eastern Wanda Mountains, one of the main Amur tiger population distribution regions in northeastern China, by using Sample Plot Method recommend by experts from America, Russia and China. This survey method was conducted as followings: During a single day, 5 teams of fieldworkers simulataneously walked 5 parallel transects, the length of each transects is at least 5 km and the interval transects is about 500 m, within one plot to provide complete coverage. Together, we surveyed 53 pots with the total sampling areas was 557.7 km² which occupied 10.34% of the total study area (5392.65 km²) and 265 transect with total survey effort about 1325 km. Our results suggested that the highest mean population density of the three preys of Amur tiger is that of roe deer ((0.4980 ± 0.0436) individuals /km²); Second is that of wild boar ((0.3423±0.0275)individuals/km²); The lowest is that of red deer ((0.2010±0.0270) individuals /km²). Using one-way ANOVA, we demonstrated that the density of each ungulate species is significant different in the mixed broadleaf stand, shrubs and shaw stands. There were also significant differences in the density of three ungulate species in different habitats. Spearman Rank correlation showed that the positive correlation between the population density of red deer and wild boar existed. The mean annual decreasing ratio of red deer, rod deer and wild boar was 13.48%, 12.69% and 1.89%, respectively in this region from 1989 to 2002. Prey scarcity affects Amur tiger by decreasing the proportion of productive females, delaying the age of first reproduction, reducing litter size, increasing offspring and adult mortalities, expanding home ranges, intensifying movements and increasing the numbers of transients and dispersing individuals. Thus, recovery and effective management of ungulate populations is a prerequisite to tiger conservation in eastern Wanda Mountains. The larger decline of main prey of Amur tiger can most likely be attributed to intensive poaching that occurred and still occurred throughout the eastern Wanda Mountains. Future conservation measures should stop this.