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野猪(Sus scrofa)不属于中国国家重点保护野生动物名录物种[1],但该物种已被列入中国国家林业局2000年8月1日发布的《国家保护的有益的或者有重要经济、科学研究价值的陆生野生动物名录》,在世界自然保护联盟红色名录中被列为:无危(LC)。野猪栖息于山地、丘陵、荒漠、森林、草地和林丛间,环境适应性极强。野猪栖息环境跨越温带与热带,从半干旱气候至热带雨林、温带林地、草原等都有其踪迹,但是没有在极干旱、海拔极高与极寒冷的地区出没。野猪繁殖能力较强,雌性野猪年产2胎,一般每胎6~8只,最多能达到14只[2]。近年来,由于野生动物保护得以加强,以及退耕还林、天保工程、林缘弃耕地复垦等其他因素造成的野猪适宜栖息地的增加,使得野猪渐渐增多。但虎、狼、豹等野生大型食肉动物数量增加相对缓慢,不能有效控制野猪种群数量。且由于食物和水源充足,加上几乎无人狩猎,野猪数量增长颇快,逐渐将活动范围扩展到了人类生活的环境,不少村庄每年都发生野猪毁田伤人事件[3-4]。
近期,非洲猪瘟(ASF)肆虐我国,其为一种急性、出血性、烈性传染病,可感染家猪和各种野猪,发病过程短,感染死亡率高达100%[5][6],目前已发现了两起野猪感染非洲猪瘟的情况[7],我省尚未发现有野猪感染的情况,但相关防控压力巨大。摸清该区域野猪分布、活动情况,为野猪管理和疫情防控提供技术支撑。
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野外调查共发现483处野生动物痕迹(实体),共计20种野生动物(见表1)。
动物种类
Species痕迹(实体)数量
Trail (Individual)
Amount所占比例/%
Percentage野猪Sus scrofa 155(2) 32.09 斑羚Naemorhedus goral 110(5) 22.77 大熊猫 Ailuropoda melanoleuca 40(0) 8.28 黑熊 Ursus thibetanus 40(0) 8.28 豹猫 Prionailurus bengalensis 31(0) 6.42 扭角羚 Budorcas tibetanus 23(0) 4.76 豪猪 Hystrix hodgsoni 19(0) 3.94 川金丝猴 Rhinopithecus roxellana 12(2) 2.49 猪獾 Arctonyx collaris 11(1) 2.28 苏门羚 Capricornis sumatraensis 10(0) 2.07 红腹角雉 Tragopan temminckii 9(8) 1.86 小麂 Muntiacus reevesi 7(1) 1.45 林麝 Moschus berezovskii 5(0) 1.04 雉鸡 Phasianus colchicus 3(3) 0.62 绿尾虹雉 Lophophorus lhuysii 3(1) 0.62 果子狸 Paguma larvata 2(0) 0.41 红腹锦鸡 Chrysolophus pictus 2(1) 0.41 毛冠鹿 Elaphodus cephalophus 1(0) 0.21 合计 Total 483(24) 100.00 Table 1. Statistical results of species and quantity of wild animal traces (individual)tity of wild animal traces (individual)
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模型运行结果显示,平均AUC值为0.918,说明模型运行结果优秀,可以用于栖息地评价(见图1)。
参与模型构建的10个环境变量中,贡献率最高的4个变量为土壤类型(37.8%)、最干月降水(17.0%)、海拔(12.0%)、优势树种(9.1%),累计贡献率达75.9%;重要值最高的4个变量为海拔(30.8%)、年平均气温(26.0%)、年降水量(14.7%)、土壤类型(13.2%),累计贡献率达84.7%(见表2)。在两种评价标准下,海拔和土壤类型都是重要的环境变量,小寨子沟保护区野猪活动痕迹在暗棕壤区域活动占比最高,主要活动海拔段集中在1500~2500 m之间,占活动痕迹总数的74.20%。
变量
Variables贡献率
Contribution
rate重要值
Permutation
importance土壤类型Soil Type 37.8 13.2 最干月降水 Driest Month Precipitation 17 0.6 海拔 Elevation 12 30.8 优势树种 Dominant Plants 9.1 3.1 最湿月降水 Wettest Month Precipitation 5.8 3 年平均气温Annual Average Temperature 5.4 26 坡度 Slope 4.9 1.4 地貌类型 Geomorphic Type 3.9 3.7 年降水量 Annual Precipitation 3.7 14.7 日温差 Daily Temperature Difference 0.4 3.6 Table 2. Variable contribution rate of wild boar suitable habitat modelble habitat model
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根据Maxent最大熵模型结果,较适宜和适宜栖息地面积为81.76km2,占保护区面积的18.42%,不适宜和次适宜的栖息地面积分别占57.57%和24.00%(见图2a)。
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保护区野猪有80.64%的活动痕迹点在年平均气温6~11℃的区域(见图2b),有85.16%的活动痕迹点在日温差9.0~10.0℃的区域(见图2c),有72.26%的活动痕迹点在年降水量790~820 mm之间的区域(见图2d),有94.84%的活动痕迹点在最湿月降水量130~160 mm的区域(见图2e),有94.19%的活动痕迹点在最干月降水6~9 mm的区域(见图2f)。
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野猪最常活动在栎类、冷杉、高山柳、灌木树种、云杉、桦木下,占到总痕迹点的76.12%(见图3a),在温带湿润季风气候和针阔混交林下发育形成的暗棕壤区域野猪活动痕迹分布占74.20%(见图3b)。在针叶阔叶混交林、落叶阔叶林和常绿落叶阔叶混交林中的活动密度最高,超过其活动痕迹总数的93%,在常绿阔叶林、灌丛、草地和落叶针叶林中的活动密度最低,其活动痕迹总数仅为7%(见图3f)。
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野猪在小寨子沟保护区主要活动范围集中在海拔段1 500~2 500 m之间,占活动痕迹总数的74.20%,3 000 m以上的高海拔段痕迹数量较少(见图3d)。主要在陡坡、斜坡活动,占活动痕迹总数的67.74%;其次为急坡、平缓坡,占活动痕迹总数的30.97%;险坡活动最少,仅占活动痕迹总数的1.29%。在中坡、谷地和平地活动频率最高,占活动痕迹总数的90.32%;上坡位、山脊活动频率最低,仅占活动痕迹总数的9.68%。且最常在半阴坡和阳坡活动,占活动痕迹总数的65.16%;阴坡和半阳坡活动频率相对较少,占活动痕迹总数的34.84%(见图3c)。所有活动痕迹点均分布在中高海拔大起伏山地和高海拔极大起伏山地两种地貌类型区域内(见图3e)。
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从野猪对不同起源林地的选择来看(见表3),在次生林中发现野猪活动的痕迹点最多,超过活动痕迹总数的75%。
林地起源
Forest origin活动痕迹点
Trail amount比例/%
Percentage次生林 Secondary 119 76.77 原始林 Primary 23 14.84 人工林 Planted 8 5.16 无林地Non-Forest 5 3.23 合计 Total 155 100.00 Table 3. Relationship between wild boar activity and forest origin
Habitat Selection Characteristics of Wild Boars in Xiaozhaizigou National Nature Reserve, Sichuan Province
doi: 10.12172/202206140001
- Received Date: 2022-06-14
- Available Online: 2023-02-04
- Publish Date: 2023-04-25
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Key words:
- Wild Boar /
- MaxEnt model model /
- Habitat characteristic
Abstract: The Eurasian wild boar is a well-known scientific name of wild boar, and its environmental adaptability is extremely strong, ranging from temperate zone to tropical zone, from semi-arid climate to tropical rain forest. In recent years, due to the continuous expansion of wild boars in Sichuan province, which has gradually affected the ecological balance and human activities. Coupled with the severe situation of prevention and control of the epidemic of African Swine Fever (ASF), relevant departments and scholars pay more and more attention to the wild boars. In order to find out the distribution and activities of wild boars in Xiaozhaizigou Nature Reserve, and provide support for the prevention of ASF and the regulation of wild boars population, the habitat suitability and selection characteristics of wild boars in Xiaozhaizigou Nature Reserve were analyzed and evaluated by means of Line Transect Method. The results showed that the MaxEnt model performed well (the average AUC = 0.918) and could be used for habitat evaluation. The suitable and sub-suitable habitat area was 81.76 km2, accounting for 18.42% of the whole nature reserve, and the unsuitable and less-suitable habitat area accounted for 57.57% and 24.00% respectively. The elevation and soil type were both important environmental variables. Most of the wild boar trails in Xiaozhaizigou Nature Reserve appeared in the dark-brown earth area, and the main activity zones were concentrated between 1500 m and 2500 m, accounting for 74.20% of the total activity trails. The main reason is that wild boars preferred to active in areas with abundant food sources. In addition, the environmental variables such as climate, geography, biology, human disturbance and other environmental variables in this study were also important factors affecting the food distribution of wild boars.bundant food sources. In addition, the environmental variables such as climate, geography, biology, human disturbance and other environmental variables in this study were also important factors affecting the food distribution of wild boars.