黑龙江凤凰山国家级自然保护区野猪冬季容纳量及最适种群密度

Winter carrying capacity and the optimum population density of wild boar in fenghuang Mountains National Nature Reserve of Heilongjiang Province

近年黑龙江省凤凰山国家级自然保护区野猪数量不断增长,人猪冲突加剧,保护区资源保护管理工作面临较大管理压力。为确定野猪种群的实际数量,同时评估该保护区的野猪的容纳量水平,以便为保护区管理局针对野猪的管理提供相关指导意见。2009-2010年冬季,在保护区采用样带调查、雪地足迹链跟踪和观察食痕的方法,并结合已有野猪生态研究确定野猪食性。野猪主要食物种类包括:木贼(Equisetum hiemale)、红松(Pinus koraiensis)果实松籽、胡桃楸(Juglans mandshurica)果实核桃、蒙古栎(Quecusmongolica)果实橡子、稠李(Padus racemosa)、榛子(Corylus heterophlla)、苔草(Carex spp.)、辽东楤木(Araliaelata)。研究期间共布设长3—5km、单侧宽度50m、总长134 km的样带30条。调查中,每隔200 m布设10 m×10 m的大样方,并在每个大样方中央及四角布设1 m×1 m的小样方,共布设大样方350个,小样方1 750个。通过样方调查,统计野猪栖息生境当年可食植物枝条及其食物种类,然后计算其食物的总供给量,再结合食物营养成分,通过粗蛋白、粗纤维、粗脂肪的能量转换,按照每克粗蛋白和粗纤维的能量转换系数为16.74kJ、每克粗脂肪的能量转换系数为37.66 kJ,确定野外生境食物总能量供给。结合野猪冬季日营养需求,以能量为基础估算保护区野猪的营养容纳量。在种群密度调查过程中,通过足迹链判断个体方法为:单一清晰足迹链确定为一个体所留,30m内多条足迹穿越同一样带被认为是一个野猪群所留,调查中根据个体分开时的足迹链数确定野猪个体数,同时将粪便、卧迹、啃食痕迹作为个体判断的辅助信息。研究结果表明:凤凰山保护区内能够提供的总能量为7.375×107MJ,冬季平均每头野猪生存所需能量为(14 677.698±409.92)MJ,野猪营养容纳量为(1 006±28)头,种群密度为(3.79±0.11)头/km2。此外,调查中发现30余个野猪套及2头野猪被猎杀现场,反应出当地的人猪冲突较为严重。结合调查中发现的野猪套数量及野猪被猎杀概率,对野猪种群数量引入20%的死亡风险系数。最终确定凤凰山野猪种群的最适数量在(603±17)头左右,最适密度为(2.27±0.06)头/km2。通过样带法调查得出凤凰山自然保护区实际野猪种群数量为(596±155)头,密度(2.24±0.58)头/km2,已趋近营养容纳量。因此,野猪并未过量,不能采取狩猎等降低种群数量的措施,同时保护区也应对野猪种群进行持续监控,防止野猪种群过度繁殖以至成灾。

Growing density of wild boar （Sus scrofa） led to human-wild boar conflict in Fenghuang Mountains National Nature Reserve. Aiming at determining density of wild boar and estimating the nutritional carrying capacity, on one hand weperformed a study to analyze forage components of wild boar by line transect backward snow track and observe method to identified food habit in field survey during late winter to early spring of survey, former records 2009 and 2010 in the reserve; and on the other hand, available plants biomass was analyzed. We located 30 line transects, （total length 134km） each width for 100 meters, length for 3--5km. On each line transect, we designed large sample plots （10m ＊ 10m） at 200m intervals, and each large sample plot was partitioned into five small sample plots （ 1 m× 1 m）. When tracing backward the snow tracks, we identified as one individual, while, what if we met several tracks left on the same transect between 30m, we followed until they parted away and the number was clear enough for counting. Nutritional carrying capacity of wild boar was determined and calculated by total energy from integrating data of crude protein, fiber and crude fat. Per gram crude protein and fiber euqals to 16.74kJ and crude fat 37. 66kJ respectively. The daily energy requirement of each wild boar was based on the research of the domestic pig. Also the data of fecals, beding sites, feeding sites of wild boar were collected as ancillary factors to get more precise results Results showed that wild boars fed mainly on Equisetum hiemale, Pinus koraiensis, Juglans mandshurica, Quecusmongolica, Padus racemosa, Corylus heterophlla, Carex spp. and Aralia elata. The nature reserve could provide 7. 375 xl07Mj energy for wild boar population and the energy requirement of every wild boar was （ 14 677. 698±409.92） MJ in winter. According to energy from habitat and that required by wild boar, we figured out that the winter nutritional carrying capacity and optimum population density of wild boar should be 1 006＋28 individuals and （3.79±0.11 ） ind/km2 respectively. However, we found more than 30 iron knots made for trapping wild boar and 2 individuals were poached by local people during the field survey. Therefore, we added 20% risk coefficient to got a more precision result, considering the death of wild boar from human disturbance （ such as poaching and trapping）. In this condition, the optimum population of wild boar should be at about （603 ±17 ） individuals and the optimum population density was （2.27 ±0.06） individuals/ km2. Finally we found out the actual population size of wild boar was 596±155 （（2.24±0.58） ind/km2）, and habitat carrying capacity was around actual population size of wild boar. We suggested that the wild boar couldn＇t be hunted and managers should take actions to prevent habitat degeneration by wild boar overabundance.