Officials at Ukraine's Pripyat-Stokhid National Nature Park (above) had expressed concern over the buildup of Russian and Belarusian troops nearby/Мокрицький Павло via Wikipedia.

Staff in some national parks in Ukraine anticipated Russia's invasion and discussed the need to join "Territorial Defense Forces," while others marked the country's Day of Unity.

Across the country, there are 49 national parks that are under the Nature-Preservation Fund of Ukraine that arose after the fall of the Soviet Union in 1991. They protect a wide variety of natural resources, from heavy spruce forests in the Carpathian Mountains to a sand-dune landscape not far from the Crimean Peninsula that Russia annexed in 2014.

Whether the invasion Thursday had any immediate impact on the country's parks was not immediately known. However, the pending invasion had led to calls for unity and preparedness across Ukraine's park system.

Officials from Cheremosky National Park, located in the Putilsky district of Chernivtsi region of the country, met on February 18 with the head of the district state administration along with the commander of the 93rd Territorial Defense Battalion in Chernivtsi region to discuss the importance of joining Ukraine's Territorial Defense Forces.

"In the event of a threat to the territorial integrity of Ukraine, their professional skills and knowledge of the area are extremely important and necessary," a release on the park's website read. "The State Protection Service of the park was invited to sign a reservist contract and join the territorial defense of Vyzhnytskyi district. Employees of Cheremosky National Park understand the need to join the Territorial Defense Forces and are ready to join them."

The park, covering nearly 18,000 acres, is located in southwestern Ukraine. It protects some of the region's unique geology, while 80 percent of the landscape is covered by spruce forest.

At Oleshkiv Sands National Nature Park, located roughly 43 miles northwest of the Crimean Peninsula, officials warned the public that there is a military training ground next to the park and that training had begun, though there was no specific date attached to the news.

At Hetman National Nature Park, while no specific mention was made of the presence of the Russian military, officials reported on Wednesday that student government representatives held an online session called the first United Ukraine TV bridge "to build a dialogue between young people from different regions of Ukraine, to show that despite the distance of thousands of kilometers, every corner of Ukraine is one state."

"Hours of air time passed quickly and productively. After the meeting, it was agreed to organize and hold further such patriotic events that unite Ukrainians and unite the Center, East and West, as well as the North and South of our state," the park reported. "After all, only in unity is our strength and the key to our future victory."

The park, popular with hikers and kayakers, lies in the valley of the Vorskla River in northeastern Ukraine near the Russian border. 

The Hutsul National Nature Park, located in a forested part of the Carpathian Mountains near the country's western border with Romania, had a link on its website readers could follow for information on joining the Territorial Defense Forces. 

Some national parks in the country celebrated February 16, which President Volodymyr Zelenskyy had declared to be a national Day of Unity.

At Ichnia National Nature Park some 74 miles northeast of Kyiv, park staff marked that day, noted Zelenskyy's declaration, and said that "[I]n order to strengthen the consolidation of Ukrainian society, strengthen its resilience in the face of growing hybrid threats. ... In fulfillment of the instructions of the Ministry of Environment, Ichnia National Nature Park joined the all-Ukrainian events: the state flag was raised in the institution, and a staff meeting was held."

A similar meeting was held at Mezyn National Nature Park located along the Desna River in the northern part of the country.

On that Day of Unity, the acting director of the Pripyat-Stokhid National Nature Park, Oleksandr Sashchuk, noted that the "Republic of Belarus, whose armed forces, together with the Russian armed forces, are brandishing weapons, conducting the exercise 'Union Determination-2022' near the lands of the Pripyat-Stokhid National Nature Park, whose territory directly borders the country."

"The most important thing today is not to panic," said Sashchuk. "We don't know the aggressor's plans. It is necessary to remain calm, work as usual and conscientiously perform the tasks assigned to employees of the institution, many of whom were directly involved in defending the sovereignty and territorial integrity of our state in the Armed Forces of Ukraine."