(Grand Haven Tribune) - An invisible line, called a tension zone, stretches across the continental United States. It represents a unique overlay of northern and southern species of plants and animals, and it cuts right through Ottawa County.
The natural diversity this brings to the Ottawa County Parks system is treasured — but also fragile.
The county is aiming to adapt parklands to the effects of climate change, which is already exacerbating shoreline erosion, stressing trees during hot summers and spreading invasive species.
About a quarter-mile of Grand River shoreline at Eastmanville Farms, south of Coopersville, has been ravaged by an invasive pest, the emerald ash borer. Other trees are unable to produce fruit in the unprecedented summer heat.
The county has applied for grant funding from the Wildlife Conservation Society Climate Adaptation Fund, in partnership with the Southwest Michigan Land Conservancy. The grant would bring trees native to southern Michigan, Indiana and Ohio that would be more resilient in the tension zone climate, according to Ottawa County Natural Resources Manager Melanie Manion.
“These trees are going to live hundreds of years,” she said. “We need to be thinking not just what is going to happen in the next 10 years, but what the changes might be 100-200 years or so.”
Several tree species within Ottawa County are at the fringe of their range. If you approach Kalamazoo to the south or Oceana County to the north, you will notice tree species native to Ottawa County disappear, Manion said.
Red pines are a northern species that is becoming vulnerable to disease amid increased temperatures, Manion explained. The species was cleared at Riley Trails, leading loggers to find the specimens light and undersized. The unhealthy trees are a direct result of warmer temperatures, Manion said.
“Like humans, when you’re stressed out you get more vulnerable to disease,” she said.
Pawpaw and hemlock, on the other hand, are at their northern range in the county. These species and others will be brought to Eastmanville Farms as seeds from their southern range. A greater diversity of genomes is expected to keep the trees reproductively healthy.
An upland portion of Eastmanville Farms will be converted to a bur oak plain, which is a southern ecosystem not previously seen in West Michigan.
Ottawa County uses the U.S. Department of Agriculture’s projection models to anticipate which species of plants and animals will survive in the future. Climate models show greater extremes of both high and low water levels, earlier springs, and rising average temperatures in the Midwest.
Adaptation strategies are being implemented now as changes are already becoming apparent, Manion explained.
“We really are the cutting edge of this climate change,” she said. “We’re already seeing some of those species are propagating a lot more in parks, whereas the others we’re not seeing as much. We’re losing some of them.”
Native plants are also part of the picture of mitigating climate change.
At Riverside Park in Robinson Township, shoreline erosion has eaten away at a historically popular site for boat launching. Restoration of the site has been halted, as the county received no bids for the work amid the historic high water levels that have drowned the potential worksite.
Projects at other Grand River Greenway sites in Jenison and at Grand Ravines Park are also on standby amid high water. It does not appear late summer will bring its typical dry conditions, according to county officials.
A team of goats tasked with grazing on invasive species at Riverside Park has multiple times become stranded amid the high waters, Manion said.
The shoreline at the park is comprised of turf grass, which has shallow roots incapable of holding on during wave action, leading to soil erosion. The turf will be replaced with native grasses with roots that run several feet deep — rather than inches.
The county originally applied for grant funding for the project during low water levels, when fish were unable to navigate a culvert from tributaries to the Grand River. Now, with the funding in hand, the culvert and parking lots are submerged.
The project entails adjusting the culvert to a height that will most of the time provide a connector for traveling fish, but will also keep the roadway dry. This arrangement will ideally serve as a happy medium, but no perfect solution can account for either climate extreme.
“We are always having to deal with these extreme weather events,” Manion said. “It’s tragic how much shoreline we lost because of these high waters and the fact we weren’t able to do the restoration in the time we had hoped to do it.”
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