Nebraskaland

NEBRASKAland July 2016

NEBRASKAland Magazine is dedicated to outstanding photography and informative writing with an engaging mix of articles and photos highlighting Nebraska’s outdoor activities, parklands, wildlife, history and people.

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JULY 2016 • NEBRASKAland 29 beetles – also from Europe – are host specific, meaning they eat only purple loosestrife plants. Each year, Hanzlik's students raise and release 5,000- 7,000 Galerucella beetles in a section of wetlands between the Niobrara golf course and the Missouri River. They carefully monitor and manage this area in hopes of lowering purple loosestrife densities. The students target .2 to .5 purple loosestrife plants per square meter, meaning in sample areas that have been divided into quadrants with PVC squares for study, they hope to find only 1 plant per every 2-5 quadrants, Hanzlik said. Purple loosestrife is not useful as feed, cover or nesting for wildlife, and its invasion also negatively impacts recreational and eco-tourism opportunities. "When we first started [conservation efforts] in 2005, populations of purple loosestrife were intense, ranging from 30 up to 100 plants per square meter. Thick growths like this totally inhibit wildlife passage except for the tiniest of creatures," said Hanzlik. "Large mammals and waterfowl will actively avoid these areas. Considering these areas are some of the few public-hunting areas around Niobrara, the plant has a drastic effect on hunting success rates." Life Cycle During the dig, which fell on May 18 this year, students dug up and collected young purple loosestrife plants near Niobrara State Park and replanted them in pots, or buckets, at the school. The pots are c overed and the plants are maintained as food to raise Galerucella beetles for release in July 2016. The class obtained breeding populations of beetles from Montana, but in the last couple years, they have been able to "round up" enough beetles locally, Hanzlik said. At this point in the spring, hibernating beetles in the bottomlands that were released by last year's class in July 2015 have already emerged from the soil and are actively feeding and breeding. They lay eggs and the adults live out the summer, continuing to feed on purple loosestrife plants until the first frost kills them. Beetles obtained this year are raised at the school. They lay clutches of eggs on the stems of the potted purple loosestrife plants and will hatch into larvae in about two weeks, around the beginning of June. They will eat voraciously for a few weeks then return to the soil to pupate. The beetles emerge in 2-3 weeks and are ravenous. "This puts us at early July 2016 when dispersion takes place. The new beetles will quickly consume all of our captive purple loosestrife plants within days or even hours," Hanzlik said. "In the fall, this generation of beetles will hibernate in the soil and surround the roots of wild plants." The process starts all over again the following spring as this year's beetles become next year's parent stock, bolstering the wild population. Typically, Hanzlik's biology class maintains 300-450 pots per year, but unfortunately due to construction of a new parking lot at Niobrara High School, 2016's project has been scaled down to 100 pots. However, the class is working on designing a greenhouse to give the project more permanency in subsequent years. Hard-earned Rewards Though purple loosestrife is challenging to control, Hanzlik's students are making an impact on populations in their study area. Previous to the Missouri River flood in 2011, introduced Galerucella beetles reduced the population down to almost "native-equivalent levels," the maximum population for an individual species to be considered non- threatening to others. However, the flood presented new complications to the project, after which purple loosestrife populations again exploded. But the students persevered and once again saw decreased levels of purple loosestrife in 2013-2015. "This spring is the first where I feel we have regained control of this area again," Hanzlik said. Niobrara High School's purple loosestrife project is one of its community's pride and joys, evidenced by the numbers of parents, community members, biologists and weed specialists who come out to assist the students each year. The project "gives students the opportunity to do real science work while engaging them in problem-based learning," said the United States Environmental Protection Agency when it awarded Niobrara High School its Region 7 President's Environmental Youth Award in 2011. Proving that high school students can make a difference, their ongoing study at Niobrara will assist biologists in future studies and management of this unwanted weed. ■ Young purple loosestrife plants are transplanted into pots to raise Galerucella beetles at Niobrara High School.

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