Butterfly Conservation Deputy Chief Executive Julie Williams has been announced as the charity's Acting Chief Executive.
Julie, who has worked at Butterfly Conservation (BC) for more than 16 years in a variety of senior roles, will take over from her predecessor Dr Martin Warren in January 2017.
Butterfly Conservation Chair, Dr Jim Asher said: "We are delighted to announce that Julie Williams has accepted the role of Acting Chief Executive for a period of one year, with a handover from Martin in December and with full effect from January 2017.
"Julie will be asked to build on Martin’s work and to drive forward and deliver BC’s strategy, with a major focus on delivery of our conservation priorities."
Julie said: "I'm thrilled and excited to be carrying on Martin's great work of leading this fantastic organisation. I would also like to wish Martin a long and happy retirement."
Martin steps down after a hugely successful career with the charity spanning more than 23 years.