China has scheduled to establish a National Park for Amur Tiger and Amur Leopard (NPATAL) of 15,000 km2 in NE China bordering Fareast Russia. One of the critical baseline information for scientific management of the park is the fair estimation of the carrying capacity of the felids’ prey, mainly sika deer, wild boar and roe deer. Unlike the habitats of other tiger subspecies, that of Amur tigers have prolonged winter (5-6 months) that is the bottleneck for the prey, and the felids as well. We focused on winter understory forage in the park to quantify the edible biomass and estimate the carrying capacity of the prey. In the summer of 2016, we set 50 pairs of 5x5m enclosure + control, each associated with a setting of camera trap, at selected sites. In the winter, we harvested tender twigs and leaves of woody plants below 2m, and herbaceous plants in two randomly chosen 1x1m plots in each enclosed and control quadrat for 20 pairs. The topographic features, snow depth, feces and other traces of the prey of each site were also surveyed.
We found: 1) the average forage biomass of upper slope (31.2±3.67 kg/ha) was significantly lower than lower slope (58.66±8.85kg/ ha). However, the average forage biomass inside enclosure did not differ significantly than that outside; 2) biomass of edible woody plant tissues, fresh grasses and withered grasses, did not differ among slope positions and between inside and outside of the enclosures, respectively; 3) the mean forage biomass (54.56±11.26 kg/ha), is lower than the summer average (282.3±16.93 kg/ha) by ~80%; 4) the winter carrying capacity of the park was ~15.3 roe deer km-2 , or ~7.7 sika deer km-2, or ~7.0 wild boar km-2; 5) forest cattle grazing significantly affected the sites through forage reduction and habitat disturbances. The results revealed: 1) the forage was in shortage in winter to decrease the carrying capacity of the prey; 2) the estimated numbers were much higher than the density monitored (0.43-0.78 roe deer km-2, 0.91-1.95 sika deer km-2 and 0.32-0.65 wild boar km-2) in the growing season, but comparable to those in the Russian sites. The results indicate that NPATAL sites have a great potential to support much larger prey populations, the NPATAL management should remove the limiting factors to increase the prey bases for the felids.