Both Amur tiger and Fareast leopard were largely extinct in the eastern mountainous area of NE China, their historical distribution centers, except few places along the SinoRussia border. A long term study showed: 1) the smaller isolated southwest subpopulation of Amur tiger were ~40, and Fareast leopard population sharing the same area with the tiger subpopulation reached 80 adults in 2014; 2) the felids greatly exceeded the carrying capacity of the occupied area; 3) they aggregated along the border showing a strong disperse tendency into China inland. Recent analyses identified forest cattle grazing in China side had the greatest negative impact on the felids by affecting their preys and habitats. This study is to quantify the impacts of cattle grazing on the prey forage and the habitats. We set 120 random line transects associated with our camera traps to survey site and overstory attributes including topographic features, tree density, canopy closure, basal area, transparency etc., and understory forage including coverage of shrubs and herb layer, biomass of leaves and tender twigs below 2.5m, herbs, grasses, and fern, in fencing grazed, less grazed and ungrazed forests on the way of the felids dispersion to China inlands.
Results/Conclusions
In this report, we focus on the results of 2015 summer survey in the regional dominated secondary oak forest. We found: 1) overstory tree BA and the forage biomass in the enclosed forest ranges was significantly lower (p < 0.05) than unclosed less used area and ungrazed sites by ~7-8 m2/ha and ~100kg/ha., respectively, and the latter two sites differed insignificantly in BA and understory biomass; 2) the composition of understory biomass differed significantly (p < 0.05) among the three sites; 3) the transparency at 1m height in the enclosed forest ranges was also significantly longer (p < 0.05) than the other two sites. These results revealed a significant change of forest understory in the enclosed forest ranges due to tree cutting, shrub clearing, and understory biomass reduction. These changes not only reduce available forage leading to a general abundance reduction of the preys, but greatly altered the critical habitat requirements for the female tigers/leopards, and their main prey, sika deer as well. Banning the large scale forest cattle grazing in the region will greatly improve the habitat quality of felids’ preys and themselves, and increase the site carrying capacity to reduce the pressure on the endangered Amur tiger and critically endangered Fareast leopard.