Seasonal Variation in Population Structure of Himalayan Ibex (Capra sibirica) in Central Karakoram National Park, Pakistan

摘要

Lack of information on seasonal population dynamics is a challenge for devising conservation strategies for Capra sibirica in Central Karakoram National Park (CKNP). In 2015–2016 we surveyed the spring and winter populations of C. sibirica in five major catchments of the park, through direct count method, using specific vantage points. Over 2,859 ibex were observed including 830 adult males, 1062 adult females, 384 yearlings, 430 kids and 153 undetermined individuals. The density increased from spring to winter in all valleys, except in Hoper. The occurrence of adult male and adult females did not vary significantly across the seasons, while for kids and yearling it varied significantly (Mann-Whitney; U=2592, α=0.000 for kids and U=3792, α=0.040 for yearlings). Sex ratio between male to female, kids to female and yearling to female varied across the seasons. Male to female sex ratios decreased from spring to winter in all valleys, (P = 0.350), except Hushey while kids to female it increased in Hisper, Hoper and Thaley, but remained unchanged in Basha and decreased in Hushey (P = 0.433). Typical group size increased in winter across all valleys whereas the mean group size also increased in all valleys, except in Basha. Group density also increased in three valleys from spring to winter. The distribution of various sex classes among various group types across the seasons changed significantly (Kruskal-Wallis test, α=0.000 for males, α=0.000 for females, α=0.007 for yearling and α=0.043 for kids). Area based multiple comparisons and linear regression (R 2 ) indicated that group size and density are linear in relation indicating high group size in high-density area than that of in mid and low-density areas. A strong correlation was observed among typical group size and habitat type (r = 0.286, P = 0.000). A positive correlation was observed among habitat type and weather (r = 0.296, P = 0.000). Seasonality as an important determinant of population dynamics should be taken into account while studying abundance and population structure of mountain ungulates.