The Barnett Reservoir may be finally clear of the Giant Salvinia after years of battling the invasive plant species.
Giant Salvinia has not been found at the reservoir since last August. In 2020, they hadn’t spotted any for the entirety of the summer until a complete and thorough grid search of the entire area in August. Three small patches of alive and thriving Giant Salvinia were discovered, and the team worked quickly to remove the plant and sprayed the area. This year, about two weeks ago, the team performed a grid search again with none being found since the last one, and it came back clear of the free-floating aquatic fern.
“They found nothing and that’s the key,” Bobby Cleveland, public liaison for the Barnett Reservoir, said. “There was no sign of any living, no sign of any dead, and you would have never known that it had been there.”
It is significant that the plant species wasn’t found in this last search because that week marked the end of summer — nearly ensuring no new growth would happen. Giant Salvinia is a tropical plant native to southeastern Brazil and Argentina. It thrives and grows in hot weather. Therefore, the end of its season in the United States is around this time of year in late September and early October as opposed to year-round in its origin place.
The Giant Salvinia is dangerous to bodies of water because it grows at a tremendously fast rate overtaking native plants and wildlife and sucking the oxygen out of the water. The plant can double in size in just 48 hours. It is most often transferred by boats that are in an infected body of water and then enter a clean body of water bringing the plant with it.
“A spot (of Giant Salvinia) the size of a card table, in a matter of weeks, can become as large as somebody’s yard and, within another few weeks, as large as a football field,” Cleveland said. “When this stuff starts growing and it is warm enough for it to really grow, it takes over everything.”
It was first spotted in the reservoir in 2012 by a biologist who happened to be driving by a boat ramp and saw the odd looking plant. He pulled it out of the water and quickly took action realizing what it was. The issue was cleared up within one day. The same thing happened several years later when somebody from the Department of Wildlife pulled his boat out of the water and noticed the plant hanging off of the back of his boat trailer in 2014. This incident was also resolved in a day.
However, the true battle against the invasive plant species began in the early summer of 2018. A large amount was found growing on the north shore of Pelahatchie Bay. They figured out it had been growing for a while after discovering the lengths the plant had spread. By the middle of the summer, it had spread all over Pelahatchie Bay and surrounding ditches and creeks.
“When we found that explosion, we started blocking it off with booms as barriers to keep it from spreading,” Cleveland said. “In October, it had spread to where they took emergency action and closed the entire Pelahatchie Bay to boating for an indefinite period.”
The Bay stayed closed until that spring in May. The infected area stayed closed for a longer period of time. During that time, the battle against the plant commenced. The reservoir contracted help from the Mississippi Department of Wildlife, Fisheries, and Parks and Wildlife and Forest and Wildlife Research Center at Mississippi State University.
“They began a program of spray with the goal of eradication, which has never been accomplished in the United States to our knowledge,” Cleveland said. “It has been controlled and managed, but it’s never been eradicated.”
However, since the bay is somewhat secluded from the entire reservoir, they had the opportunity to block it off and attack the plant within one area — an opportunity that many other infected lakes do not have. However, there were still challenges for the team working against the plant.
“[The reservoir] is still a water resource and provides drinking water so we had to be very careful to follow the labels for the chemicals that were sprayed,” Cleveland said. “That’s where the Department of Wildlife comes in. They had a specialist that does that, and I can’t commend the guy they brought in enough — Ryan Jones. I can’t tell you the hours that he has spent and the work that he has put into this for two years.”
Within a year, the team had the plant under control and thought it may be gone until the grid search at the end of the summer last year. When the three patches of remaining Giant Salvinia were found, they couldn’t claim they had eradicated the plant. However, this year’s grid search coming back clear has provided a hope that the team may have been the first to completely free an infected body of water from the Giant Salvinia.
“We aren’t one hundred percent sure that we have eradicated it, but we are confident that we have,” Cleveland said. “As of right now, with our best resources and our best people doing a thorough search, we can’t find any. Our fingers are still crossed.”
Precautions will continue to be taken for the foreseeable future to ensure the Giant Salvinia is gone and the area of water is safe to reopen, but they are confident they have done everything necessary to protect the reservoir.