Employees absconding from the organisation after a merger

Hello Senior HR's!
I am Aisha, working as a HR intern in a theatre industry.
Recently many employees have been absconding from our organisation after declaring a merger. This is especially common among the ground level staffs. Could you please suggest me ways to figure out WHY they are leaving and what are the possible factors leading to this.

Dear Friend,
This situation is commonly facing by many organisation while merging, this situation creates one kind of negative impression in employees, lot of thoughts comes in their mind.
1. How new company treats us ?
2. Change of Management Plan ?
3. Compensation wise being safe by long prospective ?
4. Concern about the company's performance ?
As a HR keep communication and transparency with employees.