Tim Pastore is stepping down as President of Original Programming and Production, National Geographic Channel, after four years. His last day will be Friday, June 1. National Geographic Global Networks CEO Courteney Monroe just announced Pastore’s pending departure in an internal memo.

Nat Geo veteran Geoff Daniels, EVP and general manager of Nat Geo WILD, will step into Pastore’s role, overseeing unscripted content for both National Geographic Channel and Nat Geo Wild, until a permanent replacement is named.

Veteran producer Pastore moved to National Geographic Channel in summer 2014, less than a year after joining National Geographic Studios, the production arm of the National Geographic Society. He was the first top programming executive hire for then-newly promoted to CEO Monroe. it was followed by the 2015 appointment of Carolyn Bernstein as head of scripted. She will continue in that capacity, continuing to report to Monroe.

“It goes without saying that Tim was an instrumental part of our transformation, and I will be forever grateful to Tim and his team for dedicating themselves to our new programming vision,” Monroe said, adding a reference to the pending Disney acquisition of key 21st Century Fox assets, including Nat Geo, which may be challenged by a rival bid from Comcast. “I know change is hard, especially at a time when we face uncertainty as a company, but rest assured that Geoff and I both have a clear vision for what we need to do and we are excited, as we enter a new fiscal year, to continue along our transformational path.”

In his own note to staff, Pastore said that he’s decided to exit the company to “pursue new opportunities” and listed some highlights from his Nat Geo tenure, series Life Below Zero, Mars and One Strange Rock, as well as launching a documentary film banner and landing two films on the Oscar shortlist within the first year.

Here are both notes in full:.

A MESSAGE FROM CEO COURTENEY MONROE

All-

I wanted to share within the broader NGP family the following note from Tim Pastore. Tim has let me know that, after four years as our president of programming, he will be leaving the channels.

It goes without saying that Tim was an instrumental part of our transformation, and I will be forever grateful to Tim and his team for dedicating themselves to our new programming vision.

I want to wish Tim all the best in his new pursuits, and I take him at his word that our paths will cross again, hopefully in the very near future!

In the interim, I have asked Geoff Daniels to step into Tim’s role, overseeing unscripted content for both National Geographic Channel and Nat Geo WILD (in addition to overseeing Kids), while I spend the next few months determining who will fill the role permanently. Carolyn Bernstein will continue to report to me, overseeing scripted content.

I know change is hard, especially at a time when we face uncertainty as a company, but rest assured that Geoff and I both have a clear vision for what we need to do and we are excited, as we enter a new fiscal year, to continue along our transformational path.

As always, I am happy to answer any questions.

Best,

Courteney

A MESSAGE FROM TIM PASTORE:

Dear Nat Geo Team,

I wanted to write to you personally to let you know that after four incredible years as president of programming for National Geographic Channels, I have decided that it’s time to pursue new opportunities. My departure brings to a close an incredibly proud chapter in my career — one that began with a bush flight into the Arctic creating a series called Life Below Zero (soon to hit 100 episodes!) and forging my relationship with this magnificent brand and company. I will always cherish working alongside all of you amazingly talented and passionate individuals. I am grateful for having had the opportunity as we moved this brand into the future.

Together we forged new creative partnerships with world-class talent; we broke new genres as we went to Mars and explored one strange rock; we envisioned how to entertain with purpose by tackling climate change, ISIS, race and gender relations; and we launched a documentary film banner landing two films on the Oscar shortlist within our first year. We did this and so much more, and always with grace and style.

Thank you to everyone who showed up each and every day with a daring commitment to pursue excellence. Every foot you put forward was your best, and that I will always remember.

My last day will be this Friday, June 1, and I look forward to spending the rest of this week thanking each of you personally for your support and friendship. I am also confident our paths will cross again very soon.

All my best,

Tim