The trust headed the campaign to buy Skokholm Island
The chief executive of Wales' largest wildlife trust has resigned saying it is facing tough times financially.
Dr Madeleine Havard is leaving her post with the Wildlife Trust of South and West Wales after almost five years.
In a joint statement issued with the trust she said it was facing "very difficult times" and she was leaving for new managers to "take it forward."
Its accounts for the last financial year show an operating loss of £107,000 but net assets of almost £2m.
The trust, which manages over 90 nature reserves in an area from Cardiff and Caerphilly in the east to Ceredigion and Pembrokeshire in the west, embarked on a number of major projects during her time at the helm.
These included spearheading the purchase of Skokholm Island off the Pembrokeshire coast and overseeing the construction of a £3.2m visitor centre on nearby Skomer Island.
The trust also advises on policy and planning and campaigns on wildlife issues.
According to its last set of accounts submitted to the Charity Commission for the financial year ending March 2008 it employs 46 people.
Dr Havard said: "We have been working flat out to try to turn the situation around, but in these very tough times have not yet been able to do so.
"I think it is now time for me to let a fresh pair of eyes look at the trust and guide it forward.
"I am very proud of everything that the trust has achieved for wildlife over the last few years, all due to the efforts of our fantastic staff, volunteers, and members.
"The trust team continues to work very hard but, in these difficult times, it needs more funds and I would ask all trust supporters, and anyone who thinks that Welsh wildlife is important, to help by joining the trust, giving a donation, or helping with fundraising.
"I know that the trust will continue to deliver at the highest level for the wildlife of south and west Wales, and wish it all the success it deserves in the future."
The trust has announced Colin Preston from the Shropshire Wildlife Trust will take over as the interim CEO from the middle of the month.
Dr Havard added: "I am delighted that Colin Preston, the highly experienced chief executive of Shropshire Wildlife Trust, has agreed to come in to help over the next few months."