黑龙江省完达山东部林区东北虎猎物生物量

研究一个地区猎物种群生物量能否满足捕食动物种群数量的需求,这对于了解濒危大型食肉动物是否受到来自于食物缺乏的威胁和制定相应的保护措施极其重要。为了掌握黑龙江省完达山东部林区东北虎食物需求与猎物生物量之间的关系,于2008年冬季至2009早春积雪覆盖期采用随机布设样线,通过收集有蹄类动物在雪地上留下的足迹等活动的方法,在东方红林业局和迎春林业局管辖境内3 692.06 km²的区域布设大样方48个,并在大样方里共布设样线240条开展有蹄类动物种群数量调查,确定东北虎猎物生物量。调查结果表明:研究地区野猪(成体502 606只,亚成体209 210只)、马鹿(成体331 357只,亚成体67 72只)和狍子(成体810 815只,亚成体202 203只)的生物量分别为74 767.50 87 825.00 kg、79 744.50 85 984.50 kg 和 31 337.00 31 525.50 kg,3种有蹄类动物生物量共计1 85 849.00 205 335.00 kg。研究地区猎物总生物量为209 619.89 231 598.24 kg。如果按8%的生物提供给东北虎,3种主要猎物生物量可满足5.22 6.92只东北虎个体的食物需求,研究地区猎物总生物量则可满足5.89 7.81只东北虎个体的食物需求。此外,对足迹遇见率与抽样强度、抽样强度与足迹遇见率的均值标准误差之间关系的分析表明,在完达山东部林区布设120条样线(抽样距离600 km)、150条样线(抽样距离750 km)和115条样线(抽样距离675 km)能满足野猪、马鹿、狍子种群数量调查准确性的最低需求。

Prey biomass of the Amur tiger (Panthera tigris altaica) in the eastern Wanda Mountains of Heilongjiang Province, China

Predicting how many individuals of a predatory species can survive within a given area, based on prey biomass, is important in understanding whether or not significant threats are related to prey availability. The study of ungulate populations and, particularly, reliable estimates of ungulate biomass are necessary for effective conservation and management of the wild Amur tiger. Dense forests, mountainous landscape and low detection probabilities preclude the use of direct count techniques in estimating ungulate populations, while direct methods are expensive and time-consuming. Indirect sampling, by counting footprints or snow tracking, is a widely use, reliable and inexpensive way of estimating ungulate populations and calculating biomass. Amur tiger-prey relationships are so close that data on prey (ungulate) availability may be used to reliably predict the tiger population and determine any threats or risks to the endangered Amur tiger. Little is known about the relationship between the Amur tiger population and ungulate biomass in the easte Wanda Mountains of Heilongjaing Province, China. Therefore, we collected data on the population size of three ungulate species (wild boar Sus scrofa, red deer Cervus elaphus and roe deer Capreolus capreolus) by establishing 240 line transects within 48 random sampling sites during late winter 2008 to early spring 2009. The results show that prey biomass, represented by the three ungulate species, was 1 85 849.00 205 335.00 kg, including 74 767.50 87 825.00 kg from wild boar (502 606 adults and 209 210 sub-adults), 79 744.50 85 984.50 kg from red deer (331 357 adults and 67 72 sub-adults) and 31 337.00 31 525.50 kg from roe deer (810 815 adults and 202 203 sub-adults). In the study area, the estimated total biomass of all prey species was 209 619.89 231 598.24 kg. The prey biomass, represented by three ungulate species, could support 5.22 6.92 Amur tiger individuals and the estimated total biomass of all prey species could support 5.89 7.81 tigers, assuming 8% biomass as the food demand of Amur tigers in the eastern Wanda Mountains. Finally, to evaluate the accuracy and precision of the line transect surveys, we analyzed the relationship between footprint frequency and sampling effort by bootstrap analysis, The differences in the coefficients of variation for footprint frequency were as follows: wild boar: 37.98% for 1 120 line transects and 2.74% for 121 240 line transects; red deer: 17.41% for 1 150 line transects and 2.86% for 151 240 line transects; roe deer: 39.72% for 1 115 line transects and 3.84% for 116 240. Trend analysis indicated that population sizes could reasonably be established from 120 line transects for wild boar (sampling distance: 600 km), 150 line transects for red deer (sampling distance: 750 km) and 115 line transects for roe deer (sampling distance: 675 km). Sampling effort, both in terms of the number of footprints and intensity of sampling, had a marked effect on the accuracy and precision of the survey results. These findings will provide scientific guidelines for the estimation of prey (ungulate) population size and conservation of the Amur tiger.