The sum of the wild Osmia will reduce year by year,which is 10980 ,7636 and 4711 in the continue three years. The ratio of year-reduce is 30%.

• 连年采集使得野生壁蜂的总数每年递减,3年的采集总数分别为10980头、7636头和4711头,年递减率达30%25以上。